Wapp

#ifndef USE_SYSTEM_SQLITE
/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.43.0.  By combining all the individual C code files into this
** single large file, the entire code can be compiled as a single translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% or more are commonly seen when SQLite is compiled as a single
** translation unit.
**
** This file is all you need to compile SQLite.  To use SQLite in other
** programs, you need this file and the "sqlite3.h" header file that defines
** the programming interface to the SQLite library.  (If you do not have
** the "sqlite3.h" header file at hand, you will find a copy embedded within
** the text of this file.  Search for "Begin file sqlite3.h" to find the start
** of the embedded sqlite3.h header file.) Additional code files may be needed
** if you want a wrapper to interface SQLite with your choice of programming
** language. The code for the "sqlite3" command-line shell is also in a
** separate file. This file contains only code for the core SQLite library.
**
** The content in this amalgamation comes from Fossil check-in
** 48f1be8cc505a7e2902c79e26c1d9a121ff.
*/
#define SQLITE_CORE 1
#define SQLITE_AMALGAMATION 1
#ifndef SQLITE_PRIVATE
# define SQLITE_PRIVATE static
#endif
/************** Begin file sqliteInt.h ***************************************/

** coverage:
**
**    NO_TEST                     - The branches on this line are not
**                                  measured by branch coverage.  This is
**                                  used on lines of code that actually
**                                  implement parts of coverage testing.
**
**    OPTIMIZATION-IF-TRUE        - This branch is allowed to always be false
**                                  and the correct answer is still obtained,
**                                  though perhaps more slowly.
**
**    OPTIMIZATION-IF-FALSE       - This branch is allowed to always be true
**                                  and the correct answer is still obtained,
**                                  though perhaps more slowly.
**
**    PREVENTS-HARMLESS-OVERREAD  - This branch prevents a buffer overread
**                                  that would be harmless and undetectable
**                                  if it did occur.
**

** been edited in any way since it was last checked in, then the last
** four hexadecimal digits of the hash may be modified.
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.43.0"
#define SQLITE_VERSION_NUMBER 3043000
#define SQLITE_SOURCE_ID      "2023-08-18 15:39:38 c48f1be8cc505a7e2902c79e26c1d9a121ff5c55785ac812d2e09232b2414695"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))

** mode database and there exists at least one client in another process that
** currently has an SQL transaction open on the database. It is set to 0 if
** the database is not a wal-mode db, or if there is no such connection in any
** other process. This opcode cannot be used to detect transactions opened
** by clients within the current process, only within other processes.
**
** <li>[[SQLITE_FCNTL_CKSM_FILE]]
** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
** [checksum VFS shim] only.
**
** <li>[[SQLITE_FCNTL_RESET_CACHE]]
** If there is currently no transaction open on the database, and the
** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
** purges the contents of the in-memory page cache. If there is an open
** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.

** practical use, but is provided so that SQLite can continue to claim the
** ability to generate new database files that are compatible with  version
** 3.0.0.
** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
** the [VACUUM] command will fail with an obscure error when attempting to
** process a table with generated columns and a descending index.  This is
** not considered a bug since SQLite versions 3.3.0 and earlier do not support
** either generated columns or descending indexes.
** </dd>
**
** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()

** not effected by the sqlite3_interrupt().
** ^A call to sqlite3_interrupt(D) that occurs when there are no running
** SQL statements is a no-op and has no effect on SQL statements
** that are started after the sqlite3_interrupt() call returns.
**
** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
** or not an interrupt is currently in effect for [database connection] D.
** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
*/
SQLITE_API void sqlite3_interrupt(sqlite3*);
SQLITE_API int sqlite3_is_interrupted(sqlite3*);

/*
** CAPI3REF: Determine If An SQL Statement Is Complete
**

** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
** function X against [database connection] D, using property mask M
** and context pointer P.  ^If the X callback is
** NULL or if the M mask is zero, then tracing is disabled.  The
** M argument should be the bitwise OR-ed combination of
** zero or more [SQLITE_TRACE] constants.
**
** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
** database connection may have at most one trace callback.
**
** ^The X callback is invoked whenever any of the events identified by
** mask M occur.  ^The integer return value from the callback is currently
** ignored, though this may change in future releases.  Callback
** implementations should return zero to ensure future compatibility.
**
** ^A trace callback is invoked with four arguments: callback(T,C,P,X).

** that check if a database file was a URI that contained a specific query
** parameter, and if so obtains the value of that query parameter.
**
** The first parameter to these interfaces (hereafter referred to
** as F) must be one of:
** <ul>
** <li> A database filename pointer created by the SQLite core and
** passed into the xOpen() method of a VFS implementation, or
** <li> A filename obtained from [sqlite3_db_filename()], or
** <li> A new filename constructed using [sqlite3_create_filename()].
** </ul>
** If the F parameter is not one of the above, then the behavior is
** undefined and probably undesirable.  Older versions of SQLite were
** more tolerant of invalid F parameters than newer versions.
**

** behavior.
*/
SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);

/*
** CAPI3REF: Create and Destroy VFS Filenames
**
** These interfaces are provided for use by [VFS shim] implementations and
** are not useful outside of that context.
**
** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
** database filename D with corresponding journal file J and WAL file W and
** with N URI parameters key/values pairs in the array P.  The result from
** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
** is safe to pass to routines like:

** prepared statement S is an EXPLAIN statement, or 2 if the
** statement S is an EXPLAIN QUERY PLAN.
** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
** an ordinary statement or a NULL pointer.
*/
SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
** METHOD: sqlite3_stmt
**
** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
** setting for [prepared statement] S.  If E is zero, then S becomes
** a normal prepared statement.  If E is 1, then S behaves as if
** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
** its SQL text began with "[EXPLAIN QUERY PLAN]".
**
** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
** SQLite tries to avoid a reprepare, but a reprepare might be necessary
** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
**
** Because of the potential need to reprepare, a call to
** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
** reprepared because it was created using [sqlite3_prepare()] instead of
** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
** hence has no saved SQL text with which to reprepare.
**
** Changing the explain setting for a prepared statement does not change
** the original SQL text for the statement.  Hence, if the SQL text originally
** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
** is called to convert the statement into an ordinary statement, the EXPLAIN
** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
** output, even though the statement now acts like a normal SQL statement.
**
** This routine returns SQLITE_OK if the explain mode is successfully
** changed, or an error code if the explain mode could not be changed.
** The explain mode cannot be changed while a statement is active.
** Hence, it is good practice to call [sqlite3_reset(S)]
** immediately prior to calling sqlite3_stmt_explain(S,E).
*/
SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);

/*
** CAPI3REF: Determine If A Prepared Statement Has Been Reset
** METHOD: sqlite3_stmt
**
** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
** [prepared statement] S has been stepped at least once using
** [sqlite3_step(S)] but has neither run to completion (returned

** ^The fifth argument to the BLOB and string binding interfaces controls
** or indicates the lifetime of the object referenced by the third parameter.
** These three options exist:
** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
** with it may be passed. ^It is called to dispose of the BLOB or string even
** if the call to the bind API fails, except the destructor is not called if
** the third parameter is a NULL pointer or the fourth parameter is negative.
** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
** the application remains responsible for disposing of the object. ^In this
** case, the object and the provided pointer to it must remain valid until
** either the prepared statement is finalized or the same SQL parameter is
** bound to something else, whichever occurs sooner.
** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
** object is to be copied prior to the return from sqlite3_bind_*(). ^The
** object and pointer to it must remain valid until then. ^SQLite will then

** ^Any SQL statement variables that had values bound to them using
** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
** Use [sqlite3_clear_bindings()] to reset the bindings.
**
** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
** back to the beginning of its program.
**
** ^The return code from [sqlite3_reset(S)] indicates whether or not
** the previous evaluation of prepared statement S completed successfully.
** ^If [sqlite3_step(S)] has never before been called on S or if
** [sqlite3_step(S)] has not been called since the previous call
** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
** [SQLITE_OK].
**
** ^If the most recent call to [sqlite3_step(S)] for the
** [prepared statement] S indicated an error, then
** [sqlite3_reset(S)] returns an appropriate [error code].
** ^The [sqlite3_reset(S)] interface might also return an [error code]
** if there were no prior errors but the process of resetting
** the prepared statement caused a new error. ^For example, if an
** [INSERT] statement with a [RETURNING] clause is only stepped one time,
** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
** the overall statement might still fail and the [sqlite3_reset(S)] call
** might return SQLITE_BUSY if locking constraints prevent the
** database change from committing.  Therefore, it is important that
** applications check the return code from [sqlite3_reset(S)] even if
** no prior call to [sqlite3_step(S)] indicated a problem.
**
** ^The [sqlite3_reset(S)] interface does not change the values
** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
*/
SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);

/*

** schema structures such as [CHECK constraints], [DEFAULT clauses],
** [expression indexes], [partial indexes], or [generated columns].
** <p>
** The SQLITE_DIRECTONLY flag is recommended for any
** [application-defined SQL function]
** that has side-effects or that could potentially leak sensitive information.
** This will prevent attacks in which an application is tricked
** into using a database file that has had its schema surreptitiously
** modified to invoke the application-defined function in ways that are
** harmful.
** <p>
** Some people say it is good practice to set SQLITE_DIRECTONLY on all
** [application-defined SQL functions], regardless of whether or not they
** are security sensitive, as doing so prevents those functions from being used
** inside of the database schema, and thus ensures that the database

** behavior.)^
**
** ^The sqlite3_mutex_leave() routine exits a mutex that was
** previously entered by the same thread.   The behavior
** is undefined if the mutex is not currently entered by the
** calling thread or is not currently allocated.
**
** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
** then any of the four routines behaves as a no-op.
**
** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
*/
SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);

#define SQLITE_TESTCTRL_RESULT_INTREAL          27
#define SQLITE_TESTCTRL_PRNG_SEED               28
#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
#define SQLITE_TESTCTRL_SEEK_COUNT              30
#define SQLITE_TESTCTRL_TRACEFLAGS              31
#define SQLITE_TESTCTRL_TUNE                    32
#define SQLITE_TESTCTRL_LOGEST                  33
#define SQLITE_TESTCTRL_USELONGDOUBLE           34
#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */

/*
** CAPI3REF: SQL Keyword Checking
**
** These routines provide access to the set of SQL language keywords
** recognized by SQLite.  Applications can uses these routines to determine
** whether or not a specific identifier needs to be escaped (for example,

** the other connections to use as the blocking connection.
**
** ^(There may be at most one unlock-notify callback registered by a
** blocked connection. If sqlite3_unlock_notify() is called when the
** blocked connection already has a registered unlock-notify callback,
** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
** called with a NULL pointer as its second argument, then any existing
** unlock-notify callback is cancelled. ^The blocked connections
** unlock-notify callback may also be cancelled by closing the blocked
** connection using [sqlite3_close()].
**
** The unlock-notify callback is not reentrant. If an application invokes
** any sqlite3_xxx API functions from within an unlock-notify callback, a
** crash or deadlock may be the result.
**
** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always

** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
** constraint handling.
** </dd>
**
** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
** <dd>Calls of the form
** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
** the [xConnect] or [xCreate] methods of a [virtual table] implementation
** prohibits that virtual table from being used from within triggers and
** views.
** </dd>
**
** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
** <dd>Calls of the form
** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the

** undefined and probably harmful.
**
** ^(A constraint on a virtual table of the form
** "[IN operator|column IN (...)]" is
** communicated to the xBestIndex method as a
** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
** this constraint, it must set the corresponding
** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
** the usual mode of handling IN operators, SQLite generates [bytecode]
** that invokes the [xFilter|xFilter() method] once for each value
** on the right-hand side of the IN operator.)^  Thus the virtual table
** only sees a single value from the right-hand side of the IN operator
** at a time.
**
** In some cases, however, it would be advantageous for the virtual

** operation; or 1 for inserts, updates, or deletes invoked by top-level
** triggers; or 2 for changes resulting from triggers called by top-level
** triggers; and so forth.
**
** When the [sqlite3_blob_write()] API is used to update a blob column,
** the pre-update hook is invoked with SQLITE_DELETE. This is because the
** in this case the new values are not available. In this case, when a
** callback made with op==SQLITE_DELETE is actually a write using the
** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
** the index of the column being written. In other cases, where the
** pre-update hook is being invoked for some other reason, including a
** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
**
** See also:  [sqlite3_update_hook()]
*/

**   significantly more efficient than those alternatives when used with
**   "detail=column" tables.
**
** xPhraseNextColumn()
**   See xPhraseFirstColumn above.
*/
struct Fts5ExtensionApi {
  int iVersion;                   /* Currently always set to 2 */

  void *(*xUserData)(Fts5Context*);

  int (*xColumnCount)(Fts5Context*);
  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);

**   provide synonyms for prefixes). However, a non-prefix query like '1st'
**   will match against "1st" and "first". This method does not require
**   extra disk space, as no extra entries are added to the FTS index.
**   On the other hand, it may require more CPU cycles to run MATCH queries,
**   as separate queries of the FTS index are required for each synonym.
**
**   When using methods (2) or (3), it is important that the tokenizer only
**   provide synonyms when tokenizing document text (method (3)) or query
**   text (method (2)), not both. Doing so will not cause any errors, but is
**   inefficient.
*/
typedef struct Fts5Tokenizer Fts5Tokenizer;
typedef struct fts5_tokenizer fts5_tokenizer;
struct fts5_tokenizer {
  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
  void (*xDelete)(Fts5Tokenizer*);

struct fts5_api {
  int iVersion;                   /* Currently always set to 2 */

  /* Create a new tokenizer */
  int (*xCreateTokenizer)(
    fts5_api *pApi,
    const char *zName,
    void *pUserData,
    fts5_tokenizer *pTokenizer,
    void (*xDestroy)(void*)
  );

  /* Find an existing tokenizer */
  int (*xFindTokenizer)(
    fts5_api *pApi,
    const char *zName,
    void **ppUserData,
    fts5_tokenizer *pTokenizer
  );

  /* Create a new auxiliary function */
  int (*xCreateFunction)(
    fts5_api *pApi,
    const char *zName,
    void *pUserData,
    fts5_extension_function xFunction,
    void (*xDestroy)(void*)
  );
};

/*
** END OF REGISTRATION API

/*
** The maximum number of terms in a compound SELECT statement.
** The code generator for compound SELECT statements does one
** level of recursion for each term.  A stack overflow can result
** if the number of terms is too large.  In practice, most SQL
** never has more than 3 or 4 terms.  Use a value of 0 to disable
** any limit on the number of terms in a compound SELECT.
*/
#ifndef SQLITE_MAX_COMPOUND_SELECT
# define SQLITE_MAX_COMPOUND_SELECT 500
#endif

/*
** The maximum number of opcodes in a VDBE program.

** The SQLITE_WITHIN(P,S,E) macro checks to see if pointer P points to
** something between S (inclusive) and E (exclusive).
**
** In other words, S is a buffer and E is a pointer to the first byte after
** the end of buffer S.  This macro returns true if P points to something
** contained within the buffer S.
*/
#define SQLITE_WITHIN(P,S,E)   (((uptr)(P)>=(uptr)(S))&&((uptr)(P)<(uptr)(E)))

/*
** P is one byte past the end of a large buffer. Return true if a span of bytes
** between S..E crosses the end of that buffer.  In other words, return true
** if the sub-buffer S..E-1 overflows the buffer whose last byte is P-1.
**
** S is the start of the span.  E is one byte past the end of end of span.
**
**                        P
**     |-----------------|                FALSE
**               |-------|
**               S        E
**
**                        P
**     |-----------------|
**                    |-------|           TRUE
**                    S        E
**
**                        P
**     |-----------------|
**                        |-------|       FALSE
**                        S        E
*/
#define SQLITE_OVERFLOW(P,S,E) (((uptr)(S)<(uptr)(P))&&((uptr)(E)>(uptr)(P)))

/*
** Macros to determine whether the machine is big or little endian,
** and whether or not that determination is run-time or compile-time.
**
** For best performance, an attempt is made to guess at the byte-order
** using C-preprocessor macros.  If that is unsuccessful, or if

  void *pBusyArg;                   /* First arg to busy callback */
  int nBusy;                        /* Incremented with each busy call */
};

/*
** Name of table that holds the database schema.
**
** The PREFERRED names are used wherever possible.  But LEGACY is also
** used for backwards compatibility.
**
**  1.  Queries can use either the PREFERRED or the LEGACY names
**  2.  The sqlite3_set_authorizer() callback uses the LEGACY name
**  3.  The PRAGMA table_list statement uses the PREFERRED name
**
** The LEGACY names are stored in the internal symbol hash table

typedef struct CteUse CteUse;
typedef struct Db Db;
typedef struct DbFixer DbFixer;
typedef struct Schema Schema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FpDecode FpDecode;
typedef struct FuncDestructor FuncDestructor;
typedef struct FuncDef FuncDef;
typedef struct FuncDefHash FuncDefHash;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct IndexedExpr IndexedExpr;
typedef struct IndexSample IndexSample;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct Lookaside Lookaside;
typedef struct LookasideSlot LookasideSlot;
typedef struct Module Module;
typedef struct NameContext NameContext;
typedef struct OnOrUsing OnOrUsing;
typedef struct Parse Parse;
typedef struct ParseCleanup ParseCleanup;
typedef struct PreUpdate PreUpdate;
typedef struct PrintfArguments PrintfArguments;
typedef struct RCStr RCStr;
typedef struct RenameToken RenameToken;
typedef struct Returning Returning;
typedef struct RowSet RowSet;
typedef struct Savepoint Savepoint;
typedef struct Select Select;
typedef struct SQLiteThread SQLiteThread;
typedef struct SelectDest SelectDest;

SQLITE_PRIVATE   void sqlite3PagerRefdump(Pager*);
  void disable_simulated_io_errors(void);
  void enable_simulated_io_errors(void);
#else
# define disable_simulated_io_errors()
# define enable_simulated_io_errors()
#endif

#ifdef SQLITE_USE_SEH
SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager*);
#endif

#endif /* SQLITE_PAGER_H */

/************** End of pager.h ***********************************************/
/************** Continuing where we left off in sqliteInt.h ******************/
/************** Include btree.h in the middle of sqliteInt.h *****************/
/************** Begin file btree.h *******************************************/

SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int flags);
SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int flags);
SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor*);
SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor*);
SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor*);

SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor*);

SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor*);
SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);

SQLITE_PRIVATE int sqlite3BtreeIntegrityCheck(
  sqlite3 *db,  /* Database connection that is running the check */

#define OPFLG_OUT3        0x20  /* out3:  P3 is an output */
#define OPFLG_NCYCLE      0x40  /* ncycle:Cycles count against P1 */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x41, 0x00,\
/*   8 */ 0x01, 0x01, 0x01, 0x01, 0x03, 0x03, 0x01, 0x01,\
/*  16 */ 0x03, 0x03, 0x01, 0x12, 0x01, 0x49, 0x49, 0x49,\
/*  24 */ 0x49, 0x01, 0x49, 0x49, 0x49, 0x49, 0x49, 0x49,\
/*  32 */ 0x41, 0x01, 0x41, 0x41, 0x41, 0x01, 0x41, 0x41,\
/*  40 */ 0x41, 0x41, 0x41, 0x26, 0x26, 0x41, 0x23, 0x0b,\
/*  48 */ 0x01, 0x01, 0x03, 0x03, 0x0b, 0x0b, 0x0b, 0x0b,\
/*  56 */ 0x0b, 0x0b, 0x01, 0x03, 0x03, 0x03, 0x01, 0x41,\
/*  64 */ 0x01, 0x00, 0x00, 0x02, 0x02, 0x08, 0x00, 0x10,\
/*  72 */ 0x10, 0x10, 0x00, 0x10, 0x00, 0x10, 0x10, 0x00,\
/*  80 */ 0x00, 0x10, 0x10, 0x00, 0x00, 0x00, 0x02, 0x02,\
/*  88 */ 0x02, 0x00, 0x00, 0x12, 0x1e, 0x20, 0x40, 0x00,\
/*  96 */ 0x00, 0x00, 0x10, 0x10, 0x00, 0x40, 0x26, 0x26,\
/* 104 */ 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26,\
/* 112 */ 0x40, 0x00, 0x12, 0x40, 0x40, 0x10, 0x40, 0x00,\
/* 120 */ 0x00, 0x00, 0x40, 0x00, 0x40, 0x40, 0x10, 0x10,\
/* 128 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x50,\
/* 136 */ 0x00, 0x40, 0x04, 0x04, 0x00, 0x40, 0x50, 0x40,\
/* 144 */ 0x10, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,\
/* 152 */ 0x00, 0x10, 0x00, 0x00, 0x06, 0x10, 0x00, 0x04,\
/* 160 */ 0x1a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 168 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x50, 0x40,\
/* 176 */ 0x00, 0x10, 0x10, 0x02, 0x00, 0x00, 0x00, 0x00,\
/* 184 */ 0x00, 0x00, 0x00,}

# define VdbeModuleComment(X)
#endif

/*
** The VdbeCoverage macros are used to set a coverage testing point
** for VDBE branch instructions.  The coverage testing points are line
** numbers in the sqlite3.c source file.  VDBE branch coverage testing
** only works with an amalgamation build.  That's ok since a VDBE branch
** coverage build designed for testing the test suite only.  No application
** should ever ship with VDBE branch coverage measuring turned on.
**
**    VdbeCoverage(v)                  // Mark the previously coded instruction
**                                     // as a branch
**
**    VdbeCoverageIf(v, conditional)   // Mark previous if conditional true
**
**    VdbeCoverageAlwaysTaken(v)       // Previous branch is always taken
**
**    VdbeCoverageNeverTaken(v)        // Previous branch is never taken
**
**    VdbeCoverageNeverNull(v)         // Previous three-way branch is only
**                                     // taken on the first two ways.  The
**                                     // NULL option is not possible
**
**    VdbeCoverageEqNe(v)              // Previous OP_Jump is only interested
**                                     // in distinguishing equal and not-equal.
**
** Every VDBE branch operation must be tagged with one of the macros above.
** If not, then when "make test" is run with -DSQLITE_VDBE_COVERAGE and
** -DSQLITE_DEBUG then an ALWAYS() will fail in the vdbeTakeBranch()
** routine in vdbe.c, alerting the developer to the missed tag.
**
** During testing, the test application will invoke
** sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE,...) to set a callback
** routine that is invoked as each bytecode branch is taken.  The callback
** contains the sqlite3.c source line number of the VdbeCoverage macro and
** flags to indicate whether or not the branch was taken.  The test application
** is responsible for keeping track of this and reporting byte-code branches
** that are never taken.
**
** See the VdbeBranchTaken() macro and vdbeTakeBranch() function in the
** vdbe.c source file for additional information.
*/

# warning Use SQLITE_DEFAULT_SYNCHRONOUS=3 instead of SQLITE_EXTRA_DURABLE
# define SQLITE_DEFAULT_SYNCHRONOUS 3
#endif

/*
** Default synchronous levels.
**
** Note that (for historical reasons) the PAGER_SYNCHRONOUS_* macros differ
** from the SQLITE_DEFAULT_SYNCHRONOUS value by 1.
**
**           PAGER_SYNCHRONOUS       DEFAULT_SYNCHRONOUS
**   OFF           1                         0
**   NORMAL        2                         1
**   FULL          3                         2
**   EXTRA         4                         3

  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
};

/*
** An instance of the following structure stores a database schema.
**
** Most Schema objects are associated with a Btree.  The exception is
** the Schema for the TEMP database (sqlite3.aDb[1]) which is free-standing.
** In shared cache mode, a single Schema object can be shared by multiple
** Btrees that refer to the same underlying BtShared object.
**
** Schema objects are automatically deallocated when the last Btree that
** references them is destroyed.   The TEMP Schema is manually freed by
** sqlite3_close().
*

  u16 szTrue;             /* True value of sz, even if disabled */
  u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */
  u32 nSlot;              /* Number of lookaside slots allocated */
  u32 anStat[3];          /* 0: hits.  1: size misses.  2: full misses */
  LookasideSlot *pInit;   /* List of buffers not previously used */
  LookasideSlot *pFree;   /* List of available buffers */
#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
  LookasideSlot *pSmallInit; /* List of small buffers not previously used */
  LookasideSlot *pSmallFree; /* List of available small buffers */
  void *pMiddle;          /* First byte past end of full-size buffers and
                          ** the first byte of LOOKASIDE_SMALL buffers */
#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
  void *pStart;           /* First byte of available memory space */
  void *pEnd;             /* First byte past end of available space */
  void *pTrueEnd;         /* True value of pEnd, when db->pnBytesFreed!=0 */
};
struct LookasideSlot {
  LookasideSlot *pNext;    /* Next buffer in the list of free buffers */
};

#define DisableLookaside  db->lookaside.bDisable++;db->lookaside.sz=0
#define EnableLookaside   db->lookaside.bDisable--;\
   db->lookaside.sz=db->lookaside.bDisable?0:db->lookaside.szTrue

/* Size of the smaller allocations in two-size lookaside */
#ifdef SQLITE_OMIT_TWOSIZE_LOOKASIDE
#  define LOOKASIDE_SMALL           0
#else
#  define LOOKASIDE_SMALL         128
#endif

/*

#define SQLITE_BalancedMerge  0x00200000 /* Balance multi-way merges */
#define SQLITE_ReleaseReg     0x00400000 /* Use OP_ReleaseReg for testing */
#define SQLITE_FlttnUnionAll  0x00800000 /* Disable the UNION ALL flattener */
   /* TH3 expects this value  ^^^^^^^^^^ See flatten04.test */
#define SQLITE_IndexedExpr    0x01000000 /* Pull exprs from index when able */
#define SQLITE_Coroutines     0x02000000 /* Co-routines for subqueries */
#define SQLITE_NullUnusedCols 0x04000000 /* NULL unused columns in subqueries */
#define SQLITE_OnePass        0x08000000 /* Single-pass DELETE and UPDATE */
#define SQLITE_AllOpts        0xffffffff /* All optimizations */

/*
** Macros for testing whether or not optimizations are enabled or disabled.
*/
#define OptimizationDisabled(db, mask)  (((db)->dbOptFlags&(mask))!=0)
#define OptimizationEnabled(db, mask)   (((db)->dbOptFlags&(mask))==0)

** are assert() statements in the code to verify this.
**
** Value constraints (enforced via assert()):
**     SQLITE_FUNC_MINMAX      ==  NC_MinMaxAgg      == SF_MinMaxAgg
**     SQLITE_FUNC_ANYORDER    ==  NC_OrderAgg       == SF_OrderByReqd
**     SQLITE_FUNC_LENGTH      ==  OPFLAG_LENGTHARG
**     SQLITE_FUNC_TYPEOF      ==  OPFLAG_TYPEOFARG
**     SQLITE_FUNC_BYTELEN     ==  OPFLAG_BYTELENARG
**     SQLITE_FUNC_CONSTANT    ==  SQLITE_DETERMINISTIC from the API
**     SQLITE_FUNC_DIRECT      ==  SQLITE_DIRECTONLY from the API
**     SQLITE_FUNC_UNSAFE      ==  SQLITE_INNOCUOUS  -- opposite meanings!!!
**     SQLITE_FUNC_ENCMASK   depends on SQLITE_UTF* macros in the API
**
** Note that even though SQLITE_FUNC_UNSAFE and SQLITE_INNOCUOUS have the
** same bit value, their meanings are inverted.  SQLITE_FUNC_UNSAFE is
** used internally and if set means that the function has side effects.
** SQLITE_INNOCUOUS is used by application code and means "not unsafe".
** See multiple instances of tag-20230109-1.
*/
#define SQLITE_FUNC_ENCMASK  0x0003 /* SQLITE_UTF8, SQLITE_UTF16BE or UTF16LE */
#define SQLITE_FUNC_LIKE     0x0004 /* Candidate for the LIKE optimization */
#define SQLITE_FUNC_CASE     0x0008 /* Case-sensitive LIKE-type function */
#define SQLITE_FUNC_EPHEM    0x0010 /* Ephemeral.  Delete with VDBE */
#define SQLITE_FUNC_NEEDCOLL 0x0020 /* sqlite3GetFuncCollSeq() might be called*/
#define SQLITE_FUNC_LENGTH   0x0040 /* Built-in length() function */
#define SQLITE_FUNC_TYPEOF   0x0080 /* Built-in typeof() function */
#define SQLITE_FUNC_BYTELEN  0x00c0 /* Built-in octet_length() function */
#define SQLITE_FUNC_COUNT    0x0100 /* Built-in count(*) aggregate */
/*                           0x0200 -- available for reuse */
#define SQLITE_FUNC_UNLIKELY 0x0400 /* Built-in unlikely() function */
#define SQLITE_FUNC_CONSTANT 0x0800 /* Constant inputs give a constant output */
#define SQLITE_FUNC_MINMAX   0x1000 /* True for min() and max() aggregates */
#define SQLITE_FUNC_SLOCHNG  0x2000 /* "Slow Change". Value constant during a
                                    ** single query - might change over time */

** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
** key is set to NULL.  SETDFLT means that the foreign key is set
** to its default value.  CASCADE means that a DELETE or UPDATE of the
** referenced table row is propagated into the row that holds the
** foreign key.
**
** The OE_Default value is a place holder that means to use whatever
** conflict resolution algorithm is required from context.
**
** The following symbolic values are used to record which type
** of conflict resolution action to take.
*/
#define OE_None     0   /* There is no constraint to check */
#define OE_Rollback 1   /* Fail the operation and rollback the transaction */
#define OE_Abort    2   /* Back out changes but do no rollback transaction */

#if SQLITE_MAX_EXPR_DEPTH>0
  int nHeight;           /* Height of the tree headed by this node */
#endif
  int iTable;            /* TK_COLUMN: cursor number of table holding column
                         ** TK_REGISTER: register number
                         ** TK_TRIGGER: 1 -> new, 0 -> old
                         ** EP_Unlikely:  134217728 times likelihood
                         ** TK_IN: ephemeral table holding RHS
                         ** TK_SELECT_COLUMN: Number of columns on the LHS
                         ** TK_SELECT: 1st register of result vector */
  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
                         ** TK_VARIABLE: variable number (always >= 1).
                         ** TK_SELECT_COLUMN: column of the result vector */
  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  union {

#define ExprAlwaysFalse(E)  (((E)->flags&(EP_OuterON|EP_IsFalse))==EP_IsFalse)

/* Macros used to ensure that the correct members of unions are accessed
** in Expr.
*/
#define ExprUseUToken(E)    (((E)->flags&EP_IntValue)==0)
#define ExprUseUValue(E)    (((E)->flags&EP_IntValue)!=0)
#define ExprUseWOfst(E)     (((E)->flags&(EP_InnerON|EP_OuterON))==0)
#define ExprUseWJoin(E)     (((E)->flags&(EP_InnerON|EP_OuterON))!=0)
#define ExprUseXList(E)     (((E)->flags&EP_xIsSelect)==0)
#define ExprUseXSelect(E)   (((E)->flags&EP_xIsSelect)!=0)
#define ExprUseYTab(E)      (((E)->flags&(EP_WinFunc|EP_Subrtn))==0)
#define ExprUseYWin(E)      (((E)->flags&EP_WinFunc)!=0)
#define ExprUseYSub(E)      (((E)->flags&EP_Subrtn)!=0)

/* Flags for use with Expr.vvaFlags

    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
    unsigned isRecursive :1;   /* True for recursive reference in WITH */
    unsigned fromDDL :1;       /* Comes from sqlite_schema */
    unsigned isCte :1;         /* This is a CTE */
    unsigned notCte :1;        /* This item may not match a CTE */
    unsigned isUsing :1;       /* u3.pUsing is valid */
    unsigned isOn :1;          /* u3.pOn was once valid and non-NULL */
    unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
    unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
  } fg;
  int iCursor;      /* The VDBE cursor number used to access this table */
  union {
    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
  } u3;

  Token constraintName;/* Name of the constraint currently being parsed */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  int nMaxArg;         /* Max args passed to user function by sub-program */
  int nSelect;         /* Number of SELECT stmts. Counter for Select.selId */
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  u32 nProgressSteps;  /* xProgress steps taken during sqlite3_prepare() */
#endif
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */
  union {
    int addrCrTab;         /* Address of OP_CreateBtree on CREATE TABLE */
    Returning *pReturning; /* The RETURNING clause */
  } u1;

  u32 oldmask;         /* Mask of old.* columns referenced */
  u32 newmask;         /* Mask of new.* columns referenced */



  LogEst nQueryLoop;   /* Est number of iterations of a query (10*log2(N)) */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 bReturning;       /* Coding a RETURNING trigger */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */

  /**************************************************************************
  ** Fields above must be initialized to zero.  The fields that follow,

#define OPFLAG_LASTROWID     0x20    /* Set to update db->lastRowid */
#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
#define OPFLAG_ISNOOP        0x40    /* OP_Delete does pre-update-hook only */
#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
#define OPFLAG_BYTELENARG    0xc0    /* OP_Column only for octet_length() */
#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
#define OPFLAG_SEEKEQ        0x02    /* OP_Open** cursor uses EQ seek only */
#define OPFLAG_FORDELETE     0x08    /* OP_Open should use BTREE_FORDELETE */
#define OPFLAG_P2ISREG       0x10    /* P2 to OP_Open** is a register number */
#define OPFLAG_PERMUTE       0x01    /* OP_Compare: use the permutation */
#define OPFLAG_SAVEPOSITION  0x02    /* OP_Delete/Insert: save cursor pos */
#define OPFLAG_AUXDELETE     0x04    /* OP_Delete: index in a DELETE op */

};
#define SQLITE_PRINTF_INTERNAL 0x01  /* Internal-use-only converters allowed */
#define SQLITE_PRINTF_SQLFUNC  0x02  /* SQL function arguments to VXPrintf */
#define SQLITE_PRINTF_MALLOCED 0x04  /* True if xText is allocated space */

#define isMalloced(X)  (((X)->printfFlags & SQLITE_PRINTF_MALLOCED)!=0)

/*
** The following object is the header for an "RCStr" or "reference-counted
** string".  An RCStr is passed around and used like any other char*
** that has been dynamically allocated.  The important interface
** differences:
**
**   1.  RCStr strings are reference counted.  They are deallocated
**       when the reference count reaches zero.
**
**   2.  Use sqlite3RCStrUnref() to free an RCStr string rather than
**       sqlite3_free()
**
**   3.  Make a (read-only) copy of a read-only RCStr string using
**       sqlite3RCStrRef().
*/
struct RCStr {
  u64 nRCRef;            /* Number of references */
  /* Total structure size should be a multiple of 8 bytes for alignment */
};

/*
** A pointer to this structure is used to communicate information
** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */

#define INITFLAG_AlterRename   0x0001  /* Reparse after a RENAME */
#define INITFLAG_AlterDrop     0x0002  /* Reparse after a DROP COLUMN */
#define INITFLAG_AlterAdd      0x0003  /* Reparse after an ADD COLUMN */

/* Tuning parameters are set using SQLITE_TESTCTRL_TUNE and are controlled
** on debug-builds of the CLI using ".testctrl tune ID VALUE".  Tuning
** parameters are for temporary use during development, to help find
** optimal values for parameters in the query planner.  The should not
** be used on trunk check-ins.  They are a temporary mechanism available
** for transient development builds only.
**
** Tuning parameters are numbered starting with 1.
*/
#define SQLITE_NTUNE  6             /* Should be zero for all trunk check-ins */
#ifdef SQLITE_DEBUG

  int bMemstat;                     /* True to enable memory status */
  u8 bCoreMutex;                    /* True to enable core mutexing */
  u8 bFullMutex;                    /* True to enable full mutexing */
  u8 bOpenUri;                      /* True to interpret filenames as URIs */
  u8 bUseCis;                       /* Use covering indices for full-scans */
  u8 bSmallMalloc;                  /* Avoid large memory allocations if true */
  u8 bExtraSchemaChecks;            /* Verify type,name,tbl_name in schema */
  u8 bUseLongDouble;                /* Make use of long double */
  int mxStrlen;                     /* Maximum string length */
  int neverCorrupt;                 /* Database is always well-formed */
  int szLookaside;                  /* Default lookaside buffer size */
  int nLookaside;                   /* Default lookaside buffer count */
  int nStmtSpill;                   /* Stmt-journal spill-to-disk threshold */
  sqlite3_mem_methods m;            /* Low-level memory allocation interface */
  sqlite3_mutex_methods mutex;      /* Low-level mutex interface */

struct Walker {
  Parse *pParse;                            /* Parser context.  */
  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
  int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
  void (*xSelectCallback2)(Walker*,Select*);/* Second callback for SELECTs */
  int walkerDepth;                          /* Number of subqueries */
  u16 eCode;                                /* A small processing code */
  u16 mWFlags;                              /* Use-dependent flags */
  union {                                   /* Extra data for callback */
    NameContext *pNC;                         /* Naming context */
    int n;                                    /* A counter */
    int iCur;                                 /* A cursor number */
    SrcList *pSrcList;                        /* FROM clause */
    struct CCurHint *pCCurHint;               /* Used by codeCursorHint() */
    struct RefSrcList *pRefSrcList;           /* sqlite3ReferencesSrcList() */

  const char *zDb;    /* Make sure all objects are contained in this database */
  const char *zType;  /* Type of the container - used for error messages */
  const Token *pName; /* Name of the container - used for error messages */
};

/* Forward declarations */
SQLITE_PRIVATE int sqlite3WalkExpr(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3WalkExprNN(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3WalkExprList(Walker*, ExprList*);
SQLITE_PRIVATE int sqlite3WalkSelect(Walker*, Select*);
SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker*, Select*);
SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker*, Select*);
SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker*, Select*);
SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker*, Select*);

*/
struct PrintfArguments {
  int nArg;                /* Total number of arguments */
  int nUsed;               /* Number of arguments used so far */
  sqlite3_value **apArg;   /* The argument values */
};

/*
** An instance of this object receives the decoding of a floating point
** value into an approximate decimal representation.
*/
struct FpDecode {
  char sign;           /* '+' or '-' */
  char isSpecial;      /* 1: Infinity  2: NaN */
  int n;               /* Significant digits in the decode */
  int iDP;             /* Location of the decimal point */
  char *z;             /* Start of significant digits */
  char zBuf[24];       /* Storage for significant digits */
};

SQLITE_PRIVATE void sqlite3FpDecode(FpDecode*,double,int,int);
SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
#endif
#if defined(SQLITE_TEST)
SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);

SQLITE_PRIVATE void sqlite3Vacuum(Parse*,Token*,Expr*);
SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*, int, sqlite3_value*);
SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, const Token*);
SQLITE_PRIVATE int sqlite3ExprCompare(const Parse*,const Expr*,const Expr*, int);
SQLITE_PRIVATE int sqlite3ExprCompareSkip(Expr*,Expr*,int);
SQLITE_PRIVATE int sqlite3ExprListCompare(const ExprList*,const ExprList*, int);
SQLITE_PRIVATE int sqlite3ExprImpliesExpr(const Parse*,const Expr*,const Expr*, int);
SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr*,int,int);
SQLITE_PRIVATE void sqlite3AggInfoPersistWalkerInit(Walker*,Parse*);
SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(Expr*, int iCur, Index *pIdx);
SQLITE_PRIVATE int sqlite3ReferencesSrcList(Parse*, Expr*, SrcList*);
SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
#ifndef SQLITE_UNTESTABLE

SQLITE_PRIVATE int sqlite3ExprIdToTrueFalse(Expr*);
SQLITE_PRIVATE int sqlite3ExprTruthValue(const Expr*);
SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr*);
SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr*);
SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*, u8);
SQLITE_PRIVATE int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
SQLITE_PRIVATE int sqlite3ExprIsTableConstant(Expr*,int);
SQLITE_PRIVATE int sqlite3ExprIsSingleTableConstraint(Expr*,const SrcList*,int);
#ifdef SQLITE_ENABLE_CURSOR_HINTS
SQLITE_PRIVATE int sqlite3ExprContainsSubquery(Expr*);
#endif
SQLITE_PRIVATE int sqlite3ExprIsInteger(const Expr*, int*);
SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
SQLITE_PRIVATE int sqlite3IsRowid(const char*);

SQLITE_PRIVATE void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
SQLITE_PRIVATE void sqlite3Detach(Parse*, Expr*);
SQLITE_PRIVATE void sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
SQLITE_PRIVATE int sqlite3FixSrcList(DbFixer*, SrcList*);
SQLITE_PRIVATE int sqlite3FixSelect(DbFixer*, Select*);
SQLITE_PRIVATE int sqlite3FixExpr(DbFixer*, Expr*);
SQLITE_PRIVATE int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);

SQLITE_PRIVATE int sqlite3RealSameAsInt(double,sqlite3_int64);
SQLITE_PRIVATE i64 sqlite3RealToI64(double);
SQLITE_PRIVATE int sqlite3Int64ToText(i64,char*);
SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*, int, u8);
SQLITE_PRIVATE int sqlite3GetInt32(const char *, int*);
SQLITE_PRIVATE int sqlite3GetUInt32(const char*, u32*);
SQLITE_PRIVATE int sqlite3Atoi(const char*);

SQLITE_PRIVATE void sqlite3FileSuffix3(const char*, char*);
#else
# define sqlite3FileSuffix3(X,Y)
#endif
SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z,u8);

SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value*, u8);
SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value*, void(*)(void*));
SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value*, u8);
SQLITE_PRIVATE void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8,
                        void(*)(void*));
SQLITE_PRIVATE void sqlite3ValueSetNull(sqlite3_value*);
SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value*);
#ifndef SQLITE_UNTESTABLE
SQLITE_PRIVATE void sqlite3ResultIntReal(sqlite3_context*);

);
SQLITE_PRIVATE void sqlite3NoopDestructor(void*);
SQLITE_PRIVATE void *sqlite3OomFault(sqlite3*);
SQLITE_PRIVATE void sqlite3OomClear(sqlite3*);
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);

SQLITE_PRIVATE char *sqlite3RCStrRef(char*);
SQLITE_PRIVATE void sqlite3RCStrUnref(char*);
SQLITE_PRIVATE char *sqlite3RCStrNew(u64);
SQLITE_PRIVATE char *sqlite3RCStrResize(char*,u64);

SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, sqlite3*, char*, int, int);
SQLITE_PRIVATE int sqlite3StrAccumEnlarge(StrAccum*, i64);
SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum*, u8);
SQLITE_PRIVATE void sqlite3ResultStrAccum(sqlite3_context*,StrAccum*);
SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);

#if SQLITE_MAX_EXPR_DEPTH>0
SQLITE_PRIVATE   int sqlite3SelectExprHeight(const Select *);
SQLITE_PRIVATE   int sqlite3ExprCheckHeight(Parse*, int);
#else
  #define sqlite3SelectExprHeight(x) 0
  #define sqlite3ExprCheckHeight(x,y)
#endif
SQLITE_PRIVATE void sqlite3ExprSetErrorOffset(Expr*,int);

SQLITE_PRIVATE u32 sqlite3Get4byte(const u8*);
SQLITE_PRIVATE void sqlite3Put4byte(u8*, u32);

#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
SQLITE_PRIVATE   void sqlite3ConnectionBlocked(sqlite3 *, sqlite3 *);
SQLITE_PRIVATE   void sqlite3ConnectionUnlocked(sqlite3 *db);

#ifdef SQLITE_32BIT_ROWID
  "32BIT_ROWID",
#endif
#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
  "4_BYTE_ALIGNED_MALLOC",
#endif



#ifdef SQLITE_ALLOW_COVERING_INDEX_SCAN
# if SQLITE_ALLOW_COVERING_INDEX_SCAN != 1
  "ALLOW_COVERING_INDEX_SCAN=" CTIMEOPT_VAL(SQLITE_ALLOW_COVERING_INDEX_SCAN),
# endif
#endif
#ifdef SQLITE_ALLOW_URI_AUTHORITY
  "ALLOW_URI_AUTHORITY",

  "INLINE_MEMCPY",
#endif
#ifdef SQLITE_INT64_TYPE
  "INT64_TYPE",
#endif
#ifdef SQLITE_INTEGRITY_CHECK_ERROR_MAX
  "INTEGRITY_CHECK_ERROR_MAX=" CTIMEOPT_VAL(SQLITE_INTEGRITY_CHECK_ERROR_MAX),
#endif
#ifdef SQLITE_LEGACY_JSON_VALID
  "LEGACY_JSON_VALID",
#endif
#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
  "LIKE_DOESNT_MATCH_BLOBS",
#endif
#ifdef SQLITE_LOCK_TRACE
  "LOCK_TRACE",
#endif

   SQLITE_DEFAULT_MEMSTATUS,  /* bMemstat */
   1,                         /* bCoreMutex */
   SQLITE_THREADSAFE==1,      /* bFullMutex */
   SQLITE_USE_URI,            /* bOpenUri */
   SQLITE_ALLOW_COVERING_INDEX_SCAN,   /* bUseCis */
   0,                         /* bSmallMalloc */
   1,                         /* bExtraSchemaChecks */
   sizeof(LONGDOUBLE_TYPE)>8, /* bUseLongDouble */
   0x7ffffffe,                /* mxStrlen */
   0,                         /* neverCorrupt */
   SQLITE_DEFAULT_LOOKASIDE,  /* szLookaside, nLookaside */
   SQLITE_STMTJRNL_SPILL,     /* nStmtSpill */
   {0,0,0,0,0,0,0,0},         /* m */
   {0,0,0,0,0,0,0,0,0},       /* mutex */
   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Elements of the linked list at Vdbe.pAuxData */
typedef struct AuxData AuxData;

/* A cache of large TEXT or BLOB values in a VdbeCursor */
typedef struct VdbeTxtBlbCache VdbeTxtBlbCache;

/* Types of VDBE cursors */
#define CURTYPE_BTREE       0
#define CURTYPE_SORTER      1
#define CURTYPE_VTAB        2
#define CURTYPE_PSEUDO      3

/*

  u8 seekOp;              /* Most recent seek operation on this cursor */
  u8 wrFlag;              /* The wrFlag argument to sqlite3BtreeCursor() */
#endif
  Bool isEphemeral:1;     /* True for an ephemeral table */
  Bool useRandomRowid:1;  /* Generate new record numbers semi-randomly */
  Bool isOrdered:1;       /* True if the table is not BTREE_UNORDERED */
  Bool noReuse:1;         /* OpenEphemeral may not reuse this cursor */
  Bool colCache:1;        /* pCache pointer is initialized and non-NULL */
  u16 seekHit;            /* See the OP_SeekHit and OP_IfNoHope opcodes */
  union {                 /* pBtx for isEphermeral.  pAltMap otherwise */
    Btree *pBtx;            /* Separate file holding temporary table */
    u32 *aAltMap;           /* Mapping from table to index column numbers */
  } ub;
  i64 seqCount;           /* Sequence counter */

  u32 *aOffset;           /* Pointer to aType[nField] */
  const u8 *aRow;         /* Data for the current row, if all on one page */
  u32 payloadSize;        /* Total number of bytes in the record */
  u32 szRow;              /* Byte available in aRow */
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
  u64 maskUsed;           /* Mask of columns used by this cursor */
#endif
  VdbeTxtBlbCache *pCache; /* Cache of large TEXT or BLOB values */

  /* 2*nField extra array elements allocated for aType[], beyond the one
  ** static element declared in the structure.  nField total array slots for
  ** aType[] and nField+1 array slots for aOffset[] */
  u32 aType[1];           /* Type values record decode.  MUST BE LAST */
};

/* Return true if P is a null-only cursor
*/
#define IsNullCursor(P) \
  ((P)->eCurType==CURTYPE_PSEUDO && (P)->nullRow && (P)->seekResult==0)


/*
** A value for VdbeCursor.cacheStatus that means the cache is always invalid.
*/
#define CACHE_STALE 0

/*
** Large TEXT or BLOB values can be slow to load, so we want to avoid
** loading them more than once.  For that reason, large TEXT and BLOB values
** can be stored in a cache defined by this object, and attached to the
** VdbeCursor using the pCache field.
*/
struct VdbeTxtBlbCache {
  char *pCValue;        /* A RCStr buffer to hold the value */
  i64 iOffset;          /* File offset of the row being cached */
  int iCol;             /* Column for which the cache is valid */
  u32 cacheStatus;      /* Vdbe.cacheCtr value */
  u32 colCacheCtr;      /* Column cache counter */
};

/*
** When a sub-program is executed (OP_Program), a structure of this type
** is allocated to store the current value of the program counter, as
** well as the current memory cell array and various other frame specific
** values stored in the Vdbe struct. When the sub-program is finished,
** these values are copied back to the Vdbe from the VdbeFrame structure,

  i64 startTime;          /* Time when query started - used for profiling */
#endif
#ifdef SQLITE_DEBUG
  int rcApp;              /* errcode set by sqlite3_result_error_code() */
  u32 nWrite;             /* Number of write operations that have occurred */
#endif
  u16 nResColumn;         /* Number of columns in one row of the result set */
  u16 nResAlloc;          /* Column slots allocated to aColName[] */
  u8 errorAction;         /* Recovery action to do in case of an error */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 prepFlags;           /* SQLITE_PREPARE_* flags */
  u8 eVdbeState;          /* On of the VDBE_*_STATE values */
  bft expired:2;          /* 1: recompile VM immediately  2: when convenient */
  bft explain:2;          /* 0: normal, 1: EXPLAIN, 2: EXPLAIN QUERY PLAN */
  bft changeCntOn:1;      /* True to update the change-counter */
  bft usesStmtJournal:1;  /* True if uses a statement journal */
  bft readOnly:1;         /* True for statements that do not write */
  bft bIsReader:1;        /* True for statements that read */
  bft haveEqpOps:1;       /* Bytecode supports EXPLAIN QUERY PLAN */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
  u32 aCounter[9];        /* Counters used by sqlite3_stmt_status() */
  char *zSql;             /* Text of the SQL statement that generated this */
#ifdef SQLITE_ENABLE_NORMALIZE
  char *zNormSql;         /* Normalization of the associated SQL statement */
  DblquoteStr *pDblStr;   /* List of double-quoted string literals */

  UnpackedRecord *pUnpacked;      /* Unpacked version of aRecord[] */
  UnpackedRecord *pNewUnpacked;   /* Unpacked version of new.* record */
  int iNewReg;                    /* Register for new.* values */
  int iBlobWrite;                 /* Value returned by preupdate_blobwrite() */
  i64 iKey1;                      /* First key value passed to hook */
  i64 iKey2;                      /* Second key value passed to hook */
  Mem *aNew;                      /* Array of new.* values */
  Table *pTab;                    /* Schema object being updated */
  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
};

/*
** An instance of this object is used to pass an vector of values into
** OP_VFilter, the xFilter method of a virtual table.  The vector is the
** set of values on the right-hand side of an IN constraint.

#else
SQLITE_PRIVATE int sqlite3VdbeMemSetZeroBlob(Mem*,int);
#endif
#ifdef SQLITE_DEBUG
SQLITE_PRIVATE int sqlite3VdbeMemIsRowSet(const Mem*);
#endif
SQLITE_PRIVATE int sqlite3VdbeMemSetRowSet(Mem*);
SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, u8, u8);
SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);
SQLITE_PRIVATE i64 sqlite3VdbeIntValue(const Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
SQLITE_PRIVATE int sqlite3VdbeBooleanValue(Mem*, int ifNull);

** The "21a-" indicates the 2-digit month followed by "-".  The "20c" indicates
** the 2-digit day which is the last integer in the set.
**
** The function returns the number of successful conversions.
*/
static int getDigits(const char *zDate, const char *zFormat, ...){
  /* The aMx[] array translates the 3rd character of each format
  ** spec into a max size:    a   b   c   d   e      f */
  static const u16 aMx[] = { 12, 14, 24, 31, 59, 14712 };
  va_list ap;
  int cnt = 0;
  char nextC;
  va_start(ap, zFormat);
  do{
    char N = zFormat[0] - '0';
    char min = zFormat[1] - '0';

  p->validYMD = 1;
}

/*
** Compute the Hour, Minute, and Seconds from the julian day number.
*/
static void computeHMS(DateTime *p){
  int day_ms, day_min; /* milliseconds, minutes into the day */
  if( p->validHMS ) return;
  computeJD(p);
  day_ms = (int)((p->iJD + 43200000) % 86400000);
  p->s = (day_ms % 60000)/1000.0;
  day_min = day_ms/60000;



  p->m = day_min % 60;
  p->h = day_min / 60;
  p->rawS = 0;
  p->validHMS = 1;
}

/*
** Compute both YMD and HMS
*/

  { 6, "second", 4.6427e+14,       1.0  },
  { 6, "minute", 7.7379e+12,      60.0  },
  { 4, "hour",   1.2897e+11,    3600.0  },
  { 3, "day",    5373485.0,    86400.0  },
  { 5, "month",  176546.0,   2592000.0  },
  { 4, "year",   14713.0,   31536000.0  },
};

/*
** If the DateTime p is raw number, try to figure out if it is
** a julian day number of a unix timestamp.  Set the p value
** appropriately.
*/
static void autoAdjustDate(DateTime *p){
  if( !p->rawS || p->validJD ){
    p->rawS = 0;
  }else if( p->s>=-21086676*(i64)10000        /* -4713-11-24 12:00:00 */
         && p->s<=(25340230*(i64)10000)+799   /*  9999-12-31 23:59:59 */
  ){
    double r = p->s*1000.0 + 210866760000000.0;
    clearYMD_HMS_TZ(p);
    p->iJD = (sqlite3_int64)(r + 0.5);
    p->validJD = 1;
    p->rawS = 0;
  }
}

/*
** Process a modifier to a date-time stamp.  The modifiers are
** as follows:
**
**     NNN days
**     NNN hours

      **    auto
      **
      ** If rawS is available, then interpret as a julian day number, or
      ** a unix timestamp, depending on its magnitude.
      */
      if( sqlite3_stricmp(z, "auto")==0 ){
        if( idx>1 ) return 1; /* IMP: R-33611-57934 */







        autoAdjustDate(p);



        rc = 0;

      }
      break;
    }
    case 'j': {
      /*
      **    julianday
      **

    case '5':
    case '6':
    case '7':
    case '8':
    case '9': {
      double rRounder;
      int i;
      int Y,M,D,h,m,x;
      const char *z2 = z;
      char z0 = z[0];
      for(n=1; z[n]; n++){
        if( z[n]==':' ) break;
        if( sqlite3Isspace(z[n]) ) break;
        if( z[n]=='-' ){
          if( n==5 && getDigits(&z[1], "40f", &Y)==1 ) break;
          if( n==6 && getDigits(&z[1], "50f", &Y)==1 ) break;
        }
      }
      if( sqlite3AtoF(z, &r, n, SQLITE_UTF8)<=0 ){
        assert( rc==1 );
        break;
      }
      if( z[n]=='-' ){
        /* A modifier of the form (+|-)YYYY-MM-DD adds or subtracts the
        ** specified number of years, months, and days.  MM is limited to
        ** the range 0-11 and DD is limited to 0-30.
        */
        if( z0!='+' && z0!='-' ) break;  /* Must start with +/- */
        if( n==5 ){
          if( getDigits(&z[1], "40f-20a-20d", &Y, &M, &D)!=3 ) break;
        }else{
          assert( n==6 );
          if( getDigits(&z[1], "50f-20a-20d", &Y, &M, &D)!=3 ) break;
          z++;
        }
        if( M>=12 ) break;                   /* M range 0..11 */
        if( D>=31 ) break;                   /* D range 0..30 */
        computeYMD_HMS(p);
        p->validJD = 0;
        if( z0=='-' ){
          p->Y -= Y;
          p->M -= M;
          D = -D;
        }else{
          p->Y += Y;
          p->M += M;
        }
        x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
        p->Y += x;
        p->M -= x*12;
        computeJD(p);
        p->validHMS = 0;
        p->validYMD = 0;
        p->iJD += (i64)D*86400000;
        if( z[11]==0 ){
          rc = 0;
          break;
        }
        if( sqlite3Isspace(z[11])
         && getDigits(&z[12], "20c:20e", &h, &m)==2
        ){
          z2 = &z[12];
          n = 2;
        }else{
          break;
        }
      }
      if( z2[n]==':' ){
        /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
        ** specified number of hours, minutes, seconds, and fractional seconds
        ** to the time.  The ".FFF" may be omitted.  The ":SS.FFF" may be
        ** omitted.
        */

        DateTime tx;
        sqlite3_int64 day;
        if( !sqlite3Isdigit(*z2) ) z2++;
        memset(&tx, 0, sizeof(tx));
        if( parseHhMmSs(z2, &tx) ) break;
        computeJD(&tx);
        tx.iJD -= 43200000;
        day = tx.iJD/86400000;
        tx.iJD -= day*86400000;
        if( z0=='-' ) tx.iJD = -tx.iJD;
        computeJD(p);
        clearYMD_HMS_TZ(p);
        p->iJD += tx.iJD;
        rc = 0;
        break;
      }

      /* If control reaches this point, it means the transformation is
      ** one of the forms like "+NNN days".  */
      z += n;
      while( sqlite3Isspace(*z) ) z++;
      n = sqlite3Strlen30(z);
      if( n>10 || n<3 ) break;
      if( sqlite3UpperToLower[(u8)z[n-1]]=='s' ) n--;
      computeJD(p);
      assert( rc==1 );
      rRounder = r<0 ? -0.5 : +0.5;
      for(i=0; i<ArraySize(aXformType); i++){
        if( aXformType[i].nName==n
         && sqlite3_strnicmp(aXformType[i].zName, z, n)==0
         && r>-aXformType[i].rLimit && r<aXformType[i].rLimit
        ){
          switch( i ){
            case 4: { /* Special processing to add months */

              assert( strcmp(aXformType[i].zName,"month")==0 );
              computeYMD_HMS(p);
              p->M += (int)r;
              x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
              p->Y += x;
              p->M -= x*12;
              p->validJD = 0;

    zBuf[12] = '0' + (x.h/10)%10;
    zBuf[13] = '0' + (x.h)%10;
    zBuf[14] = ':';
    zBuf[15] = '0' + (x.m/10)%10;
    zBuf[16] = '0' + (x.m)%10;
    zBuf[17] = ':';
    if( x.useSubsec ){
      s = (int)(1000.0*x.s + 0.5);
      zBuf[18] = '0' + (s/10000)%10;
      zBuf[19] = '0' + (s/1000)%10;
      zBuf[20] = '.';
      zBuf[21] = '0' + (s/100)%10;
      zBuf[22] = '0' + (s/10)%10;
      zBuf[23] = '0' + (s)%10;
      zBuf[24] = 0;

    zBuf[0] = '0' + (x.h/10)%10;
    zBuf[1] = '0' + (x.h)%10;
    zBuf[2] = ':';
    zBuf[3] = '0' + (x.m/10)%10;
    zBuf[4] = '0' + (x.m)%10;
    zBuf[5] = ':';
    if( x.useSubsec ){
      s = (int)(1000.0*x.s + 0.5);
      zBuf[6] = '0' + (s/10000)%10;
      zBuf[7] = '0' + (s/1000)%10;
      zBuf[8] = '.';
      zBuf[9] = '0' + (s/100)%10;
      zBuf[10] = '0' + (s/10)%10;
      zBuf[11] = '0' + (s)%10;
      zBuf[12] = 0;

**   %H  hour 00-24
**   %j  day of year 000-366
**   %J  ** julian day number
**   %m  month 01-12
**   %M  minute 00-59
**   %s  seconds since 1970-01-01
**   %S  seconds 00-59
**   %w  day of week 0-6  Sunday==0
**   %W  week of year 00-53
**   %Y  year 0000-9999
**   %%  %
*/
static void strftimeFunc(
  sqlite3_context *context,
  int argc,

  sqlite3_context *context,
  int NotUsed,
  sqlite3_value **NotUsed2
){
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  dateFunc(context, 0, 0);
}

/*
** timediff(DATE1, DATE2)
**
** Return the amount of time that must be added to DATE2 in order to
** convert it into DATE2.  The time difference format is:
**
**     +YYYY-MM-DD HH:MM:SS.SSS
**
** The initial "+" becomes "-" if DATE1 occurs before DATE2.  For
** date/time values A and B, the following invariant should hold:
**
**     datetime(A) == (datetime(B, timediff(A,B))
**
** Both DATE arguments must be either a julian day number, or an
** ISO-8601 string.  The unix timestamps are not supported by this
** routine.
*/
static void timediffFunc(
  sqlite3_context *context,
  int NotUsed1,
  sqlite3_value **argv
){
  char sign;
  int Y, M;
  DateTime d1, d2;
  sqlite3_str sRes;
  UNUSED_PARAMETER(NotUsed1);
  if( isDate(context, 1, &argv[0], &d1) ) return;
  if( isDate(context, 1, &argv[1], &d2) ) return;
  computeYMD_HMS(&d1);
  computeYMD_HMS(&d2);
  if( d1.iJD>=d2.iJD ){
    sign = '+';
    Y = d1.Y - d2.Y;
    if( Y ){
      d2.Y = d1.Y;
      d2.validJD = 0;
      computeJD(&d2);
    }
    M = d1.M - d2.M;
    if( M<0 ){
      Y--;
      M += 12;
    }
    if( M!=0 ){
      d2.M = d1.M;
      d2.validJD = 0;
      computeJD(&d2);
    }
    while( d1.iJD<d2.iJD ){
      M--;
      if( M<0 ){
        M = 11;
        Y--;
      }
      d2.M--;
      if( d2.M<1 ){
        d2.M = 12;
        d2.Y--;
      }
      d2.validJD = 0;
      computeJD(&d2);
    }
    d1.iJD -= d2.iJD;
    d1.iJD += (u64)1486995408 * (u64)100000;
  }else /* d1<d2 */{
    sign = '-';
    Y = d2.Y - d1.Y;
    if( Y ){
      d2.Y = d1.Y;
      d2.validJD = 0;
      computeJD(&d2);
    }
    M = d2.M - d1.M;
    if( M<0 ){
      Y--;
      M += 12;
    }
    if( M!=0 ){
      d2.M = d1.M;
      d2.validJD = 0;
      computeJD(&d2);
    }
    while( d1.iJD>d2.iJD ){
      M--;
      if( M<0 ){
        M = 11;
        Y--;
      }
      d2.M++;
      if( d2.M>12 ){
        d2.M = 1;
        d2.Y++;
      }
      d2.validJD = 0;
      computeJD(&d2);
    }
    d1.iJD = d2.iJD - d1.iJD;
    d1.iJD += (u64)1486995408 * (u64)100000;
  }
  d1.validYMD = 0;
  d1.validHMS = 0;
  d1.validTZ = 0;
  computeYMD_HMS(&d1);
  sqlite3StrAccumInit(&sRes, 0, 0, 0, 100);
  sqlite3_str_appendf(&sRes, "%c%04d-%02d-%02d %02d:%02d:%06.3f",
       sign, Y, M, d1.D-1, d1.h, d1.m, d1.s);
  sqlite3ResultStrAccum(context, &sRes);
}


/*
** current_timestamp()
**
** This function returns the same value as datetime('now').
*/
static void ctimestampFunc(

#ifndef SQLITE_OMIT_DATETIME_FUNCS
    PURE_DATE(julianday,        -1, 0, 0, juliandayFunc ),
    PURE_DATE(unixepoch,        -1, 0, 0, unixepochFunc ),
    PURE_DATE(date,             -1, 0, 0, dateFunc      ),
    PURE_DATE(time,             -1, 0, 0, timeFunc      ),
    PURE_DATE(datetime,         -1, 0, 0, datetimeFunc  ),
    PURE_DATE(strftime,         -1, 0, 0, strftimeFunc  ),
    PURE_DATE(timediff,          2, 0, 0, timediffFunc  ),
    DFUNCTION(current_time,      0, 0, 0, ctimeFunc     ),
    DFUNCTION(current_timestamp, 0, 0, 0, ctimestampFunc),
    DFUNCTION(current_date,      0, 0, 0, cdateFunc     ),
#else
    STR_FUNCTION(current_time,      0, "%H:%M:%S",          0, currentTimeFunc),
    STR_FUNCTION(current_date,      0, "%Y-%m-%d",          0, currentTimeFunc),
    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),

   && op!=SQLITE_FCNTL_LOCK_TIMEOUT
   && op!=SQLITE_FCNTL_CKPT_DONE
   && op!=SQLITE_FCNTL_CKPT_START
  ){
    /* Faults are not injected into COMMIT_PHASETWO because, assuming SQLite
    ** is using a regular VFS, it is called after the corresponding
    ** transaction has been committed. Injecting a fault at this point
    ** confuses the test scripts - the COMMIT command returns SQLITE_NOMEM
    ** but the transaction is committed anyway.
    **
    ** The core must call OsFileControl() though, not OsFileControlHint(),
    ** as if a custom VFS (e.g. zipvfs) returns an error here, it probably
    ** means the commit really has failed and an error should be returned
    ** to the user.
    **

}

/*
** Like free() but works for allocations obtained from sqlite3MemMalloc()
** or sqlite3MemRealloc().
**
** For this low-level routine, we already know that pPrior!=0 since
** cases where pPrior==0 will have been intercepted and dealt with
** by higher-level routines.
*/
static void sqlite3MemFree(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
  SQLITE_FREE(pPrior);
#else
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;

#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
  int cpuCount;
  size_t len;
  if( _sqliteZone_ ){
    return SQLITE_OK;
  }
  len = sizeof(cpuCount);
  /* One usually wants to use hw.activecpu for MT decisions, but not here */
  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
  if( cpuCount>1 ){
    /* defer MT decisions to system malloc */
    _sqliteZone_ = malloc_default_zone();
  }else{
    /* only 1 core, use our own zone to contention over global locks,
    ** e.g. we have our own dedicated locks */

*/
#ifdef SQLITE_MUTEX_PTHREADS

#include <pthread.h>

/*
** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
** are necessary under two conditions:  (1) Debug builds and (2) using
** home-grown mutexes.  Encapsulate these conditions into a single #define.
*/
#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
# define SQLITE_MUTEX_NREF 1
#else
# define SQLITE_MUTEX_NREF 0
#endif

/*
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
  int id;                    /* Mutex type */
#ifdef SQLITE_DEBUG
  volatile int nRef;         /* Number of entrances */
  volatile DWORD owner;      /* Thread holding this mutex */
  volatile LONG trace;       /* True to trace changes */
#endif
};

/*
** These are the initializer values used when declaring a "static" mutex

/* Notes:
**
**    %S    Takes a pointer to SrcItem.  Shows name or database.name
**    %!S   Like %S but prefer the zName over the zAlias
*/




















































/*
** Set the StrAccum object to an error mode.
*/
SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum *p, u8 eError){
  assert( eError==SQLITE_NOMEM || eError==SQLITE_TOOBIG );
  p->accError = eError;
  if( p->mxAlloc ) sqlite3_str_reset(p);

  etByte flag_long;          /* 1 for the "l" flag, 2 for "ll", 0 by default */
  etByte done;               /* Loop termination flag */
  etByte cThousand;          /* Thousands separator for %d and %u */
  etByte xtype = etINVALID;  /* Conversion paradigm */
  u8 bArgList;               /* True for SQLITE_PRINTF_SQLFUNC */
  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
  sqlite_uint64 longvalue;   /* Value for integer types */
  double realvalue;          /* Value for real types */


  const et_info *infop;      /* Pointer to the appropriate info structure */
  char *zOut;                /* Rendering buffer */
  int nOut;                  /* Size of the rendering buffer */
  char *zExtra = 0;          /* Malloced memory used by some conversion */

  int exp, e2;               /* exponent of real numbers */


  etByte flag_dp;            /* True if decimal point should be shown */
  etByte flag_rtz;           /* True if trailing zeros should be removed */

  PrintfArguments *pArgList = 0; /* Arguments for SQLITE_PRINTF_SQLFUNC */
  char buf[etBUFSIZE];       /* Conversion buffer */

  /* pAccum never starts out with an empty buffer that was obtained from
  ** malloc().  This precondition is required by the mprintf("%z...")
  ** optimization. */
  assert( pAccum->nChar>0 || (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );

          pre = &aPrefix[infop->prefix];
          for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
        }
        length = (int)(&zOut[nOut-1]-bufpt);
        break;
      case etFLOAT:
      case etEXP:
      case etGENERIC: {
        FpDecode s;
        int iRound;
        int j;

        if( bArgList ){
          realvalue = getDoubleArg(pArgList);
        }else{
          realvalue = va_arg(ap,double);
        }



        if( precision<0 ) precision = 6;         /* Set default precision */
#ifdef SQLITE_FP_PRECISION_LIMIT
        if( precision>SQLITE_FP_PRECISION_LIMIT ){
          precision = SQLITE_FP_PRECISION_LIMIT;
        }
#endif
        if( xtype==etFLOAT ){
          iRound = -precision;
        }else if( xtype==etGENERIC ){
          iRound = precision;
        }else{
          iRound = precision+1;
        }
        sqlite3FpDecode(&s, realvalue, iRound, flag_altform2 ? 26 : 16);
        if( s.isSpecial ){
          if( s.isSpecial==2 ){
            bufpt = flag_zeropad ? "null" : "NaN";
            length = sqlite3Strlen30(bufpt);
            break;
          }else if( flag_zeropad ){
            s.z[0] = '9';
            s.iDP = 1000;
            s.n = 1;
          }else{
            memcpy(buf, "-Inf", 5);
            bufpt = buf;
            if( s.sign=='-' ){
              /* no-op */
            }else if( flag_prefix ){
              buf[0] = flag_prefix;
            }else{
              bufpt++;
            }
            length = sqlite3Strlen30(bufpt);
            break;
          }
        }
        if( s.sign=='-' ){
          prefix = '-';
        }else{
          prefix = flag_prefix;
        }

        exp = s.iDP-1;
        if( xtype==etGENERIC && precision>0 ) precision--;


































































        /*
        ** If the field type is etGENERIC, then convert to either etEXP
        ** or etFLOAT, as appropriate.
        */
        if( xtype==etGENERIC ){
          flag_rtz = !flag_alternateform;
          if( exp<-4 || exp>precision ){
            xtype = etEXP;
          }else{
            precision = precision - exp;
            xtype = etFLOAT;
          }
        }else{
          flag_rtz = flag_altform2;
        }
        if( xtype==etEXP ){
          e2 = 0;
        }else{
          e2 = s.iDP - 1;
        }

        bufpt = buf;
        {
          i64 szBufNeeded;           /* Size of a temporary buffer needed */
          szBufNeeded = MAX(e2,0)+(i64)precision+(i64)width+15;
          if( cThousand && e2>0 ) szBufNeeded += (e2+2)/3;
          if( szBufNeeded > etBUFSIZE ){
            bufpt = zExtra = printfTempBuf(pAccum, szBufNeeded);
            if( bufpt==0 ) return;
          }
        }
        zOut = bufpt;
        flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
        /* The sign in front of the number */
        if( prefix ){
          *(bufpt++) = prefix;
        }
        /* Digits prior to the decimal point */
        j = 0;
        if( e2<0 ){
          *(bufpt++) = '0';





        }else{
          for(; e2>=0; e2--){
            *(bufpt++) = j<s.n ? s.z[j++] : '0';
            if( cThousand && (e2%3)==0 && e2>1 ) *(bufpt++) = ',';
          }
        }
        /* The decimal point */
        if( flag_dp ){
          *(bufpt++) = '.';
        }
        /* "0" digits after the decimal point but before the first
        ** significant digit of the number */
        for(e2++; e2<0 && precision>0; precision--, e2++){

          *(bufpt++) = '0';
        }
        /* Significant digits after the decimal point */

        while( (precision--)>0 ){




          *(bufpt++) = j<s.n ? s.z[j++] : '0';

        }
        /* Remove trailing zeros and the "." if no digits follow the "." */
        if( flag_rtz && flag_dp ){
          while( bufpt[-1]=='0' ) *(--bufpt) = 0;
          assert( bufpt>zOut );
          if( bufpt[-1]=='.' ){
            if( flag_altform2 ){
              *(bufpt++) = '0';
            }else{
              *(--bufpt) = 0;
            }
          }
        }
        /* Add the "eNNN" suffix */
        if( xtype==etEXP ){
          exp = s.iDP - 1;
          *(bufpt++) = aDigits[infop->charset];
          if( exp<0 ){
            *(bufpt++) = '-'; exp = -exp;
          }else{
            *(bufpt++) = '+';
          }
          if( exp>=100 ){

          for(i=width; i>=nPad; i--){
            bufpt[i] = bufpt[i-nPad];
          }
          i = prefix!=0;
          while( nPad-- ) bufpt[i++] = '0';
          length = width;
        }

        break;
      }
      case etSIZE:
        if( !bArgList ){
          *(va_arg(ap,int*)) = pAccum->nChar;
        }
        length = width = 0;
        break;
      case etPERCENT:

SQLITE_API void sqlite3_str_appendf(StrAccum *p, const char *zFormat, ...){
  va_list ap;
  va_start(ap,zFormat);
  sqlite3_str_vappendf(p, zFormat, ap);
  va_end(ap);
}


/*****************************************************************************
** Reference counted string storage
*****************************************************************************/

/*
** Increase the reference count of the string by one.
**
** The input parameter is returned.
*/
SQLITE_PRIVATE char *sqlite3RCStrRef(char *z){
  RCStr *p = (RCStr*)z;
  assert( p!=0 );
  p--;
  p->nRCRef++;
  return z;
}

/*
** Decrease the reference count by one.  Free the string when the
** reference count reaches zero.
*/
SQLITE_PRIVATE void sqlite3RCStrUnref(char *z){
  RCStr *p = (RCStr*)z;
  assert( p!=0 );
  p--;
  assert( p->nRCRef>0 );
  if( p->nRCRef>=2 ){
    p->nRCRef--;
  }else{
    sqlite3_free(p);
  }
}

/*
** Create a new string that is capable of holding N bytes of text, not counting
** the zero byte at the end.  The string is uninitialized.
**
** The reference count is initially 1.  Call sqlite3RCStrUnref() to free the
** newly allocated string.
**
** This routine returns 0 on an OOM.
*/
SQLITE_PRIVATE char *sqlite3RCStrNew(u64 N){
  RCStr *p = sqlite3_malloc64( N + sizeof(*p) + 1 );
  if( p==0 ) return 0;
  p->nRCRef = 1;
  return (char*)&p[1];
}

/*
** Change the size of the string so that it is able to hold N bytes.
** The string might be reallocated, so return the new allocation.
*/
SQLITE_PRIVATE char *sqlite3RCStrResize(char *z, u64 N){
  RCStr *p = (RCStr*)z;
  RCStr *pNew;
  assert( p!=0 );
  p--;
  assert( p->nRCRef==1 );
  pNew = sqlite3_realloc64(p, N+sizeof(RCStr)+1);
  if( pNew==0 ){
    sqlite3_free(p);
    return 0;
  }else{
    return (char*)&pNew[1];
  }
}

/************** End of printf.c **********************************************/
/************** Begin file treeview.c ****************************************/
/*
** 2015-06-08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:

    case TK_TRUTH: {
      int x;
      const char *azOp[] = {
         "IS-FALSE", "IS-TRUE", "IS-NOT-FALSE", "IS-NOT-TRUE"
      };
      assert( pExpr->op2==TK_IS || pExpr->op2==TK_ISNOT );
      assert( pExpr->pRight );
      assert( sqlite3ExprSkipCollateAndLikely(pExpr->pRight)->op
                  == TK_TRUEFALSE );
      x = (pExpr->op2==TK_ISNOT)*2 + sqlite3ExprTruthValue(pExpr->pRight);
      zUniOp = azOp[x];
      break;
    }

    case TK_SPAN: {
      assert( !ExprHasProperty(pExpr, EP_IntValue) );

#ifndef SQLITE_OMIT_FLOATING_POINT
#include <math.h>
#endif

/*
** Calls to sqlite3FaultSim() are used to simulate a failure during testing,
** or to bypass normal error detection during testing in order to let
** execute proceed further downstream.
**
** In deployment, sqlite3FaultSim() *always* return SQLITE_OK (0).  The
** sqlite3FaultSim() function only returns non-zero during testing.
**
** During testing, if the test harness has set a fault-sim callback using
** a call to sqlite3_test_control(SQLITE_TESTCTRL_FAULT_INSTALL), then
** each call to sqlite3FaultSim() is relayed to that application-supplied

/*
** Load the sqlite3.iSysErrno field if that is an appropriate thing
** to do based on the SQLite error code in rc.
*/
SQLITE_PRIVATE void sqlite3SystemError(sqlite3 *db, int rc){
  if( rc==SQLITE_IOERR_NOMEM ) return;
#ifdef SQLITE_USE_SEH
  if( rc==SQLITE_IOERR_IN_PAGE ){
    int ii;
    int iErr;
    sqlite3BtreeEnterAll(db);
    for(ii=0; ii<db->nDb; ii++){
      if( db->aDb[ii].pBt ){
        iErr = sqlite3PagerWalSystemErrno(sqlite3BtreePager(db->aDb[ii].pBt));
        if( iErr ){
          db->iSysErrno = iErr;
        }
      }
    }
    sqlite3BtreeLeaveAll(db);
    return;
  }
#endif
  rc &= 0xff;
  if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
    db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
  }
}

/*

  while( z[0] ){
    h += UpperToLower[(unsigned char)z[0]];
    z++;
  }
  return h;
}

/* Double-Double multiplication.  (x[0],x[1]) *= (y,yy)


**
** Reference:
**   T. J. Dekker, "A Floating-Point Technique for Extending the
**   Available Precision".  1971-07-26.
*/
static void dekkerMul2(volatile double *x, double y, double yy){

  /*
  ** The "volatile" keywords on parameter x[] and on local variables
  ** below are needed force intermediate results to be truncated to
  ** binary64 rather than be carried around in an extended-precision
  ** format.  The truncation is necessary for the Dekker algorithm to
  ** work.  Intel x86 floating point might omit the truncation without
  ** the use of volatile.

  */
  volatile double tx, ty, p, q, c, cc;
  double hx, hy;
  u64 m;

  memcpy(&m, (void*)&x[0], 8);
  m &= 0xfffffffffc000000LL;
  memcpy(&hx, &m, 8);
  tx = x[0] - hx;
  memcpy(&m, &y, 8);
  m &= 0xfffffffffc000000LL;
  memcpy(&hy, &m, 8);

  ty = y - hy;

  p = hx*hy;
  q = hx*ty + tx*hy;
  c = p+q;

  cc = p - c + q + tx*ty;
  cc = x[0]*yy + x[1]*y + cc;
  x[0] = c + cc;
  x[1] = c - x[0];
  x[1] += cc;



}

/*
** The string z[] is an text representation of a real number.
** Convert this string to a double and write it into *pResult.
**
** The string z[] is length bytes in length (bytes, not characters) and

#endif
SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
#ifndef SQLITE_OMIT_FLOATING_POINT
  int incr;
  const char *zEnd;
  /* sign * significand * (10 ^ (esign * exponent)) */
  int sign = 1;    /* sign of significand */
  u64 s = 0;       /* significand */
  int d = 0;       /* adjust exponent for shifting decimal point */
  int esign = 1;   /* sign of exponent */
  int e = 0;       /* exponent */
  int eValid = 1;  /* True exponent is either not used or is well-formed */

  int nDigit = 0;  /* Number of digits processed */
  int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */

  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
  *pResult = 0.0;   /* Default return value, in case of an error */
  if( length==0 ) return 0;

    z+=incr;
  }

  /* copy max significant digits to significand */
  while( z<zEnd && sqlite3Isdigit(*z) ){
    s = s*10 + (*z - '0');
    z+=incr; nDigit++;
    if( s>=((LARGEST_UINT64-9)/10) ){
      /* skip non-significant significand digits
      ** (increase exponent by d to shift decimal left) */
      while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
    }
  }
  if( z>=zEnd ) goto do_atof_calc;

  /* if decimal point is present */
  if( *z=='.' ){
    z+=incr;
    eType++;
    /* copy digits from after decimal to significand
    ** (decrease exponent by d to shift decimal right) */
    while( z<zEnd && sqlite3Isdigit(*z) ){
      if( s<((LARGEST_UINT64-9)/10) ){
        s = s*10 + (*z - '0');
        d--;
        nDigit++;
      }
      z+=incr;
    }
  }

    }
  }

  /* skip trailing spaces */
  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;

do_atof_calc:
  /* Zero is a special case */
  if( s==0 ){
    *pResult = sign<0 ? -0.0 : +0.0;
    goto atof_return;
  }

  /* adjust exponent by d, and update sign */
  e = (e*esign) + d;






  /* Try to adjust the exponent to make it smaller */










  while( e>0 && s<(LARGEST_UINT64/10) ){


    s *= 10;
    e--;

  }
  while( e<0 && (s%10)==0 ){
    s /= 10;
    e++;
  }







  if( e==0 ){
    *pResult = s;
  }else if( sqlite3Config.bUseLongDouble ){



    LONGDOUBLE_TYPE r = (LONGDOUBLE_TYPE)s;
    if( e>0 ){

      while( e>=100  ){ e-=100; r *= 1.0e+100L; }
      while( e>=10   ){ e-=10;  r *= 1.0e+10L;  }
      while( e>=1    ){ e-=1;   r *= 1.0e+01L;  }
    }else{

      while( e<=-100 ){ e+=100; r *= 1.0e-100L; }
      while( e<=-10  ){ e+=10;  r *= 1.0e-10L;  }
      while( e<=-1   ){ e+=1;   r *= 1.0e-01L;  }
    }
    assert( r>=0.0 );
    if( r>+1.7976931348623157081452742373e+308L ){


#ifdef INFINITY
      *pResult = +INFINITY;
#else
      *pResult = 1.0e308*10.0;
#endif
    }else{
      *pResult = (double)r;
    }
  }else{
    double rr[2];
    u64 s2;
    rr[0] = (double)s;
    s2 = (u64)rr[0];
    rr[1] = s>=s2 ? (double)(s - s2) : -(double)(s2 - s);
    if( e>0 ){
      while( e>=100  ){
        e -= 100;
        dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
      }
      while( e>=10   ){
        e -= 10;
        dekkerMul2(rr, 1.0e+10, 0.0);
      }
      while( e>=1    ){
        e -= 1;
        dekkerMul2(rr, 1.0e+01, 0.0);
      }
    }else{
      while( e<=-100 ){
        e += 100;
        dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
      }
      while( e<=-10  ){
        e += 10;
        dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
      }
      while( e<=-1   ){
        e += 1;
        dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
      }
    }
    *pResult = rr[0]+rr[1];
    if( sqlite3IsNaN(*pResult) ) *pResult = 1e300*1e300;
  }
  if( sign<0 ) *pResult = -*pResult;
  assert( !sqlite3IsNaN(*pResult) );

atof_return:
  /* return true if number and no extra non-whitespace characters after */
  if( z==zEnd && nDigit>0 && eValid && eType>0 ){
    return eType;
  }else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
    return -1;
  }else{
    return 0;
  }

  testcase( i==18*incr );
  testcase( i==19*incr );
  testcase( i==20*incr );
  if( u>LARGEST_INT64 ){
    /* This test and assignment is needed only to suppress UB warnings
    ** from clang and -fsanitize=undefined.  This test and assignment make
    ** the code a little larger and slower, and no harm comes from omitting
    ** them, but we must appease the undefined-behavior pharisees. */
    *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
  }else if( neg ){
    *pNum = -(i64)u;
  }else{
    *pNum = (i64)u;
  }
  rc = 0;

    memcpy(pOut, &u, 8);
    if( k-i>16 ) return 2;
    if( z[k]!=0 ) return 1;
    return 0;
  }else
#endif /* SQLITE_OMIT_HEX_INTEGER */
  {
    int n = (int)(0x3fffffff&strspn(z,"+- \n\t0123456789"));
    if( z[n] ) n++;
    return sqlite3Atoi64(z, pOut, n, SQLITE_UTF8);
  }
}

/*
** If zNum represents an integer that will fit in 32-bits, then set
** *pValue to that integer and return true.  Otherwise return false.
**

** string is not an integer, just return 0.
*/
SQLITE_PRIVATE int sqlite3Atoi(const char *z){
  int x = 0;
  sqlite3GetInt32(z, &x);
  return x;
}

/*
** Decode a floating-point value into an approximate decimal
** representation.
**
** Round the decimal representation to n significant digits if
** n is positive.  Or round to -n signficant digits after the
** decimal point if n is negative.  No rounding is performed if
** n is zero.
**
** The significant digits of the decimal representation are
** stored in p->z[] which is a often (but not always) a pointer
** into the middle of p->zBuf[].  There are p->n significant digits.
** The p->z[] array is *not* zero-terminated.
*/
SQLITE_PRIVATE void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
  int i;
  u64 v;
  int e, exp = 0;
  p->isSpecial = 0;
  p->z = p->zBuf;

  /* Convert negative numbers to positive.  Deal with Infinity, 0.0, and
  ** NaN. */
  if( r<0.0 ){
    p->sign = '-';
    r = -r;
  }else if( r==0.0 ){
    p->sign = '+';
    p->n = 1;
    p->iDP = 1;
    p->z = "0";
    return;
  }else{
    p->sign = '+';
  }
  memcpy(&v,&r,8);
  e = v>>52;
  if( (e&0x7ff)==0x7ff ){
    p->isSpecial = 1 + (v!=0x7ff0000000000000LL);
    p->n = 0;
    p->iDP = 0;
    return;
  }

  /* Multiply r by powers of ten until it lands somewhere in between
  ** 1.0e+19 and 1.0e+17.
  */
  if( sqlite3Config.bUseLongDouble ){
    LONGDOUBLE_TYPE rr = r;
    if( rr>=1.0e+19 ){
      while( rr>=1.0e+119L ){ exp+=100; rr *= 1.0e-100L; }
      while( rr>=1.0e+29L  ){ exp+=10;  rr *= 1.0e-10L;  }
      while( rr>=1.0e+19L  ){ exp++;    rr *= 1.0e-1L;   }
    }else{
      while( rr<1.0e-97L   ){ exp-=100; rr *= 1.0e+100L; }
      while( rr<1.0e+07L   ){ exp-=10;  rr *= 1.0e+10L;  }
      while( rr<1.0e+17L   ){ exp--;    rr *= 1.0e+1L;   }
    }
    v = (u64)rr;
  }else{
    /* If high-precision floating point is not available using "long double",
    ** then use Dekker-style double-double computation to increase the
    ** precision.
    **
    ** The error terms on constants like 1.0e+100 computed using the
    ** decimal extension, for example as follows:
    **
    **   SELECT decimal_exp(decimal_sub('1.0e+100',decimal(1.0e+100)));
    */
    double rr[2];
    rr[0] = r;
    rr[1] = 0.0;
    if( rr[0]>1.84e+19 ){
      while( rr[0]>1.84e+119 ){
        exp += 100;
        dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
      }
      while( rr[0]>1.84e+29 ){
        exp += 10;
        dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
      }
      while( rr[0]>1.84e+19 ){
        exp += 1;
        dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
      }
    }else{
      while( rr[0]<1.84e-82  ){
        exp -= 100;
        dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
      }
      while( rr[0]<1.84e+08  ){
        exp -= 10;
        dekkerMul2(rr, 1.0e+10, 0.0);
      }
      while( rr[0]<1.84e+18  ){
        exp -= 1;
        dekkerMul2(rr, 1.0e+01, 0.0);
      }
    }
    v = rr[1]<0.0 ? (u64)rr[0]-(u64)(-rr[1]) : (u64)rr[0]+(u64)rr[1];
  }


  /* Extract significant digits. */
  i = sizeof(p->zBuf)-1;
  assert( v>0 );
  while( v ){  p->zBuf[i--] = (v%10) + '0'; v /= 10; }
  assert( i>=0 && i<sizeof(p->zBuf)-1 );
  p->n = sizeof(p->zBuf) - 1 - i;
  assert( p->n>0 );
  assert( p->n<sizeof(p->zBuf) );
  p->iDP = p->n + exp;
  if( iRound<0 ){
    iRound = p->iDP - iRound;
    if( iRound==0 && p->zBuf[i+1]>='5' ){
      iRound = 1;
      p->zBuf[i--] = '0';
      p->n++;
      p->iDP++;
    }
  }
  if( iRound>0 && (iRound<p->n || p->n>mxRound) ){
    char *z = &p->zBuf[i+1];
    if( iRound>mxRound ) iRound = mxRound;
    p->n = iRound;
    if( z[iRound]>='5' ){
      int j = iRound-1;
      while( 1 /*exit-by-break*/ ){
        z[j]++;
        if( z[j]<='9' ) break;
        z[j] = '0';
        if( j==0 ){
          p->z[i--] = '1';
          p->n++;
          p->iDP++;
          break;
        }else{
          j--;
        }
      }
    }
  }
  p->z = &p->zBuf[i+1];
  assert( i+p->n < sizeof(p->zBuf) );
  while( ALWAYS(p->n>0) && p->z[p->n-1]=='0' ){ p->n--; }
}

/*
** Try to convert z into an unsigned 32-bit integer.  Return true on
** success and false if there is an error.
**
** Only decimal notation is accepted.
*/

    return 0;
  }else{
    return 1;
  }
}

/*
** Attempt to add, subtract, or multiply the 64-bit signed value iB against
** the other 64-bit signed integer at *pA and store the result in *pA.
** Return 0 on success.  Or if the operation would have resulted in an
** overflow, leave *pA unchanged and return 1.
*/
SQLITE_PRIVATE int sqlite3AddInt64(i64 *pA, i64 iB){
#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
  return __builtin_add_overflow(*pA, iB, pA);

** This file contains inline asm code for retrieving "high-performance"
** counters for x86 and x86_64 class CPUs.
*/
#ifndef SQLITE_HWTIME_H
#define SQLITE_HWTIME_H

/*
** The following routine only works on Pentium-class (or newer) processors.
** It uses the RDTSC opcode to read the cycle count value out of the
** processor and returns that value.  This can be used for high-res
** profiling.
*/
#if !defined(__STRICT_ANSI__) && \
    (defined(__GNUC__) || defined(_MSC_VER)) && \
    (defined(i386) || defined(__i386__) || defined(_M_IX86))

    if( pH->first ){ pH->first->prev = pNew; }
    pNew->prev = 0;
    pH->first = pNew;
  }
}


/* Resize the hash table so that it contains "new_size" buckets.
**
** The hash table might fail to resize if sqlite3_malloc() fails or
** if the new size is the same as the prior size.
** Return TRUE if the resize occurs and false if not.
*/
static int rehash(Hash *pH, unsigned int new_size){
  struct _ht *new_ht;            /* The new hash table */

** implementation uses Posix Advisory Locks.  Alternative implementations
** use flock(), dot-files, various proprietary locking schemas, or simply
** skip locking all together.
**
** This source file is organized into divisions where the logic for various
** subfunctions is contained within the appropriate division.  PLEASE
** KEEP THE STRUCTURE OF THIS FILE INTACT.  New code should be placed
** in the correct division and should be clearly labelled.
**
** The layout of divisions is as follows:
**
**   *  General-purpose declarations and utility functions.
**   *  Unique file ID logic used by VxWorks.
**   *  Various locking primitive implementations (all except proxy locking):
**      + for Posix Advisory Locks

#else
  return 0;
#endif
}

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes.  Return SQLITE_OK upon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
*/
static int unixSetSystemCall(
  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
  const char *zName,            /* Name of system call to override */
  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */

** a locked and an unlocked state.
**
** But wait:  there are yet more problems with POSIX advisory locks.
**
** If you close a file descriptor that points to a file that has locks,
** all locks on that file that are owned by the current process are
** released.  To work around this problem, each unixInodeInfo object
** maintains a count of the number of pending locks on the inode.
** When an attempt is made to close an unixFile, if there are
** other unixFile open on the same inode that are holding locks, the call
** to close() the file descriptor is deferred until all of the locks clear.
** The unixInodeInfo structure keeps a list of file descriptors that need to
** be closed and that list is walked (and cleared) when the last lock
** clears.
**
** Yet another problem:  LinuxThreads do not play well with posix locks.
**
** Many older versions of linux use the LinuxThreads library which is
** not posix compliant.  Under LinuxThreads, a lock created by thread
** A cannot be modified or overridden by a different thread B.
** Only thread A can modify the lock.  Locking behavior is correct
** if the application uses the newer Native Posix Thread Library (NPTL)
** on linux - with NPTL a lock created by thread A can override locks
** in thread B.  But there is no way to know at compile-time which
** threading library is being used.  So there is no way to know at
** compile-time whether or not thread A can override locks on thread B.
** One has to do a run-time check to discover the behavior of the
** current process.
**

** a convenient place to set a breakpoint.
*/
static void storeLastErrno(unixFile *pFile, int error){
  pFile->lastErrno = error;
}

/*
** Close all file descriptors accumulated in the unixInodeInfo->pUnused list.
*/
static void closePendingFds(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;
  assert( unixFileMutexHeld(pFile) );
  for(p=pInode->pUnused; p; p=pNext){

  /* The following describes the implementation of the various locks and
  ** lock transitions in terms of the POSIX advisory shared and exclusive
  ** lock primitives (called read-locks and write-locks below, to avoid
  ** confusion with SQLite lock names). The algorithms are complicated
  ** slightly in order to be compatible with Windows95 systems simultaneously
  ** accessing the same database file, in case that is ever required.
  **
  ** Symbols defined in os.h identify the 'pending byte' and the 'reserved
  ** byte', each single bytes at well known offsets, and the 'shared byte
  ** range', a range of 510 bytes at a well known offset.
  **
  ** To obtain a SHARED lock, a read-lock is obtained on the 'pending
  ** byte'.  If this is successful, 'shared byte range' is read-locked
  ** and the lock on the 'pending byte' released.  (Legacy note:  When
  ** SQLite was first developed, Windows95 systems were still very common,
  ** and Windows95 lacks a shared-lock capability.  So on Windows95, a
  ** single randomly selected by from the 'shared byte range' is locked.
  ** Windows95 is now pretty much extinct, but this work-around for the
  ** lack of shared-locks on Windows95 lives on, for backwards
  ** compatibility.)
  **
  ** A process may only obtain a RESERVED lock after it has a SHARED lock.
  ** A RESERVED lock is implemented by grabbing a write-lock on the
  ** 'reserved byte'.
  **
  ** An EXCLUSIVE lock may only be requested after either a SHARED or
  ** RESERVED lock is held. An EXCLUSIVE lock is implemented by obtaining
  ** a write-lock on the entire 'shared byte range'. Since all other locks
  ** require a read-lock on one of the bytes within this range, this ensures
  ** that no other locks are held on the database.
  **
  ** If a process that holds a RESERVED lock requests an EXCLUSIVE, then
  ** a PENDING lock is obtained first. A PENDING lock is implemented by
  ** obtaining a write-lock on the 'pending byte'. This ensures that no new
  ** SHARED locks can be obtained, but existing SHARED locks are allowed to
  ** persist. If the call to this function fails to obtain the EXCLUSIVE
  ** lock in this case, it holds the PENDING lock instead. The client may
  ** then re-attempt the EXCLUSIVE lock later on, after existing SHARED
  ** locks have cleared.
  */
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  unixInodeInfo *pInode;
  struct flock lock;

    OSTRACE(("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
            azFileLock(eFileLock)));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct.
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pending lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
  assert( eFileLock!=PENDING_LOCK );
  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );

  /* This mutex is needed because pFile->pInode is shared across threads

    OSTRACE(("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
           azFileLock(eFileLock)));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pending lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
  assert( eFileLock!=PENDING_LOCK );
  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );

  /* This mutex is needed because pFile->pInode is shared across threads

      /* Remove the shared lock before trying the range.  we'll need to
      ** reestablish the shared lock if we can't get the  afpUnlock
      */
      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
                         pInode->sharedByte, 1, 0)) ){
        int failed2 = SQLITE_OK;
        /* now attempt to get the exclusive lock range */
        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST,
                               SHARED_SIZE, 1);
        if( failed && (failed2 = afpSetLock(context->dbPath, pFile,
                       SHARED_FIRST + pInode->sharedByte, 1, 1)) ){
          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
          ** a critical I/O error
          */

  assert( pFile->pPreallocatedUnused==0
       || offset>=PENDING_BYTE+512
       || offset+amt<=PENDING_BYTE
  );
#endif

#if SQLITE_MAX_MMAP_SIZE>0
  /* Deal with as much of this read request as possible by transferring
  ** data from the memory mapping using memcpy().  */
  if( offset<pFile->mmapSize ){
    if( offset+amt <= pFile->mmapSize ){
      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
      return SQLITE_OK;
    }else{
      int nCopy = pFile->mmapSize - offset;

        pFile->transCntrChng = 1;  /* The transaction counter has changed */
      }
    }
  }
#endif

#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
  /* Deal with as much of this write request as possible by transferring
  ** data from the memory mapping using memcpy().  */
  if( offset<pFile->mmapSize ){
    if( offset+amt <= pFile->mmapSize ){
      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
      return SQLITE_OK;
    }else{
      int nCopy = pFile->mmapSize - offset;

  if( fullSync ) sqlite3_fullsync_count++;
  sqlite3_sync_count++;
#endif

  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
  ** no-op.  But go ahead and call fstat() to validate the file
  ** descriptor as we need a method to provoke a failure during
  ** coverage testing.
  */
#ifdef SQLITE_NO_SYNC
  {
    struct stat buf;
    rc = osFstat(fd, &buf);
  }
#elif HAVE_FULLFSYNC

** The argument is the number of microseconds we want to sleep.
** The return value is the number of microseconds of sleep actually
** requested from the underlying operating system, a number which
** might be greater than or equal to the argument, but not less
** than the argument.
*/
static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){
#if !defined(HAVE_NANOSLEEP) || HAVE_NANOSLEEP+0
  struct timespec sp;

  sp.tv_sec = microseconds / 1000000;
  sp.tv_nsec = (microseconds % 1000000) * 1000;

  /* Almost all modern unix systems support nanosleep().  But if you are
  ** compiling for one of the rare exceptions, you can use
  ** -DHAVE_NANOSLEEP=0 (perhaps in conjuction with -DHAVE_USLEEP if
  ** usleep() is available) in order to bypass the use of nanosleep() */
  nanosleep(&sp, NULL);

  UNUSED_PARAMETER(NotUsed);
  return microseconds;
#elif defined(HAVE_USLEEP) && HAVE_USLEEP
  if( microseconds>=1000000 ) sleep(microseconds/1000000);
  if( microseconds%1000000 ) usleep(microseconds%1000000);
  UNUSED_PARAMETER(NotUsed);
  return microseconds;

#define osFlushViewOfFile \
        ((BOOL(WINAPI*)(LPCVOID,SIZE_T))aSyscall[79].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK upon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
*/
static int winSetSystemCall(
  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
  const char *zName,            /* Name of system call to override */
  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */

  assert( offset>=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE(("READ pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
           pFile->h, pBuf, amt, offset, pFile->locktype));

#if SQLITE_MAX_MMAP_SIZE>0
  /* Deal with as much of this read request as possible by transferring
  ** data from the memory mapping using memcpy().  */
  if( offset<pFile->mmapSize ){
    if( offset+amt <= pFile->mmapSize ){
      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
      OSTRACE(("READ-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
               osGetCurrentProcessId(), pFile, pFile->h));
      return SQLITE_OK;

  SimulateDiskfullError(return SQLITE_FULL);

  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
           pFile->h, pBuf, amt, offset, pFile->locktype));

#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
  /* Deal with as much of this write request as possible by transferring
  ** data from the memory mapping using memcpy().  */
  if( offset<pFile->mmapSize ){
    if( offset+amt <= pFile->mmapSize ){
      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
      OSTRACE(("WRITE-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
               osGetCurrentProcessId(), pFile, pFile->h));
      return SQLITE_OK;

    ** though some folks might complain that the file is bigger than it
    ** needs to be.
    **
    ** The only feasible work-around is to defer the truncation until after
    ** all references to memory-mapped content are closed.  That is doable,
    ** but involves adding a few branches in the common write code path which
    ** could slow down normal operations slightly.  Hence, we have decided for
    ** now to simply make transactions a no-op if there are pending reads.  We
    ** can maybe revisit this decision in the future.
    */
    return SQLITE_OK;
  }
#endif

  assert( pFile );

           osGetCurrentProcessId(), pFile, pFile->h, sqlite3ErrName(rc)));
  return rc;
}

#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs.  This is used to test
** that syncs and fullsyncs are occurring at the right times.
*/
SQLITE_API int sqlite3_sync_count = 0;
SQLITE_API int sqlite3_fullsync_count = 0;
#endif

/*
** Make sure all writes to a particular file are committed to disk.

    gotPendingLock = 0;
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    (void)winUnlockReadLock(pFile);
    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, SHARED_FIRST, 0,
                      SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      lastErrno = osGetLastError();
      winGetReadLock(pFile);

*/
static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  size_t i, j;
  DWORD pid;
  int nPre = sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX);
  int nMax, nBuf, nDir, nLen;
  char *zBuf;

  /* It's odd to simulate an io-error here, but really this is just
  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing.

    return winLogError(SQLITE_ERROR, 0, "winGetTempname5", 0);
  }

  sqlite3_snprintf(nBuf-16-nLen, zBuf+nLen, SQLITE_TEMP_FILE_PREFIX);

  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness(15, &zBuf[j]);
  pid = osGetCurrentProcessId();
  for(i=0; i<15; i++, j++){
    zBuf[j] += pid & 0xff;
    pid >>= 8;
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  zBuf[j+1] = 0;
  *pzBuf = zBuf;

  OSTRACE(("TEMP-FILENAME name=%s, rc=SQLITE_OK\n", zBuf));

  if( p->iSize<=BITVEC_NBIT ){
    p->u.aBitmap[i/BITVEC_SZELEM] |= 1 << (i&(BITVEC_SZELEM-1));
    return SQLITE_OK;
  }
  h = BITVEC_HASH(i++);
  /* if there wasn't a hash collision, and this doesn't */
  /* completely fill the hash, then just add it without */
  /* worrying about sub-dividing and re-hashing. */
  if( !p->u.aHash[h] ){
    if (p->nSet<(BITVEC_NINT-1)) {
      goto bitvec_set_end;
    } else {
      goto bitvec_set_rehash;
    }
  }

static int numberOfCachePages(PCache *p){
  if( p->szCache>=0 ){
    /* IMPLEMENTATION-OF: R-42059-47211 If the argument N is positive then the
    ** suggested cache size is set to N. */
    return p->szCache;
  }else{
    i64 n;
    /* IMPLEMENTATION-OF: R-59858-46238 If the argument N is negative, then the
    ** number of cache pages is adjusted to be a number of pages that would
    ** use approximately abs(N*1024) bytes of memory based on the current
    ** page size. */
    n = ((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
    if( n>1000000000 ) n = 1000000000;
    return (int)n;
  }

      }
    }
  }
  return result.pDirty;
}

/*
** Sort the list of pages in ascending order by pgno.  Pages are
** connected by pDirty pointers.  The pDirtyPrev pointers are
** corrupted by this sort.
**
** Since there cannot be more than 2^31 distinct pages in a database,
** there cannot be more than 31 buckets required by the merge sorter.
** One extra bucket is added to catch overflow in case something
** ever changes to make the previous sentence incorrect.

** bulk allocation can be adjusted using
**
**     sqlite3_config(SQLITE_CONFIG_PAGECACHE, (void*)0, 0, N).
**
** If N is positive, then N pages worth of memory are allocated using a single
** sqlite3Malloc() call and that memory is used for the first N pages allocated.
** Or if N is negative, then -1024*N bytes of memory are allocated and used
** for as many pages as can be accommodated.
**
** Only one of (2) or (3) can be used.  Once the memory available to (2) or
** (3) is exhausted, subsequent allocations fail over to the general-purpose
** memory allocator (1).
**
** Earlier versions of SQLite used only methods (1) and (2).  But experiments
** show that method (3) with N==100 provides about a 5% performance boost for

**
** Variables isBulkLocal and isAnchor were once type "u8". That works,
** but causes a 2-byte gap in the structure for most architectures (since
** pointers must be either 4 or 8-byte aligned). As this structure is located
** in memory directly after the associated page data, if the database is
** corrupt, code at the b-tree layer may overread the page buffer and
** read part of this structure before the corruption is detected. This
** can cause a valgrind error if the uninitialized gap is accessed. Using u16
** ensures there is no such gap, and therefore no bytes of uninitialized
** memory in the structure.
**
** The pLruNext and pLruPrev pointers form a double-linked circular list
** of all pages that are unpinned.  The PGroup.lru element (which should be
** the only element on the list with PgHdr1.isAnchor set to 1) forms the
** beginning and the end of the list.

** allocated in chunks so most INSERTs do no allocation.  There is an
** upper bound on the size of allocated memory.  No memory is freed
** until DESTROY.
**
** The TEST primitive includes a "batch" number.  The TEST primitive
** will only see elements that were inserted before the last change
** in the batch number.  In other words, if an INSERT occurs between
** two TESTs where the TESTs have the same batch number, then the
** value added by the INSERT will not be visible to the second TEST.
** The initial batch number is zero, so if the very first TEST contains
** a non-zero batch number, it will see all prior INSERTs.
**
** No INSERTs may occurs after a SMALLEST.  An assertion will fail if
** that is attempted.
**

/* Return the sqlite3_file object for the WAL file */
SQLITE_PRIVATE sqlite3_file *sqlite3WalFile(Wal *pWal);

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
SQLITE_PRIVATE int sqlite3WalWriteLock(Wal *pWal, int bLock);
SQLITE_PRIVATE void sqlite3WalDb(Wal *pWal, sqlite3 *db);
#endif

#ifdef SQLITE_USE_SEH
SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal*);
#endif

#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* SQLITE_WAL_H */

/************** End of wal.h *************************************************/
/************** Continuing where we left off in pager.c **********************/

**    instead of READER following such an error.
**
**    Once it has entered the ERROR state, any attempt to use the pager
**    to read or write data returns an error. Eventually, once all
**    outstanding transactions have been abandoned, the pager is able to
**    transition back to OPEN state, discarding the contents of the
**    page-cache and any other in-memory state at the same time. Everything
**    is reloaded from disk (and, if necessary, hot-journal rollback performed)
**    when a read-transaction is next opened on the pager (transitioning
**    the pager into READER state). At that point the system has recovered
**    from the error.
**
**    Specifically, the pager jumps into the ERROR state if:
**
**      1. An error occurs while attempting a rollback. This happens in

**
**   + 4 bytes: PAGER_SJ_PGNO.
**   + N bytes: super-journal filename in utf-8.
**   + 4 bytes: N (length of super-journal name in bytes, no nul-terminator).
**   + 4 bytes: super-journal name checksum.
**   + 8 bytes: aJournalMagic[].
**
** The super-journal page checksum is the sum of the bytes in the super-journal
** name, where each byte is interpreted as a signed 8-bit integer.
**
** If zSuper is a NULL pointer (occurs for a single database transaction),
** this call is a no-op.
*/
static int writeSuperJournal(Pager *pPager, const char *zSuper){
  int rc;                          /* Return code */

   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8,
                                 iHdrOff+4+nSuper+8)))
  ){
    return rc;
  }
  pPager->journalOff += (nSuper+20);

  /* If the pager is in persistent-journal mode, then the physical
  ** journal-file may extend past the end of the super-journal name
  ** and 8 bytes of magic data just written to the file. This is
  ** dangerous because the code to rollback a hot-journal file
  ** will not be able to find the super-journal name to determine
  ** whether or not the journal is hot.
  **
  ** Easiest thing to do in this scenario is to truncate the journal

  pPager->journalOff = 0;
  pPager->journalHdr = 0;
  pPager->setSuper = 0;
}

/*
** This function is called whenever an IOERR or FULL error that requires
** the pager to transition into the ERROR state may have occurred.
** The first argument is a pointer to the pager structure, the second
** the error-code about to be returned by a pager API function. The
** value returned is a copy of the second argument to this function.
**
** If the second argument is SQLITE_FULL, SQLITE_IOERR or one of the
** IOERR sub-codes, the pager enters the ERROR state and the error code
** is stored in Pager.errCode. While the pager remains in the ERROR state,

    }
  }
  pager_unlock(pPager);
}

/*
** Parameter aData must point to a buffer of pPager->pageSize bytes
** of data. Compute and return a checksum based on the contents of the
** page of data and the current value of pPager->cksumInit.
**
** This is not a real checksum. It is really just the sum of the
** random initial value (pPager->cksumInit) and every 200th byte
** of the page data, starting with byte offset (pPager->pageSize%200).
** Each byte is interpreted as an 8-bit unsigned integer.
**

  int rc;                         /* Return code */
  int nList;                      /* Number of pages in pList */
  PgHdr *p;                       /* For looping over pages */

  assert( pPager->pWal );
  assert( pList );
#ifdef SQLITE_DEBUG
  /* Verify that the page list is in ascending order */
  for(p=pList; p && p->pDirty; p=p->pDirty){
    assert( p->pgno < p->pDirty->pgno );
  }
#endif

  assert( pList->pDirty==0 || isCommit );
  if( isCommit ){

  *pnPage = nPage;
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_WAL
/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists if the database is not empty, or verify that the *-wal file does
** not exist (by deleting it) if the database file is empty.
**
** If the database is not empty and the *-wal file exists, open the pager
** in WAL mode.  If the database is empty or if no *-wal file exists and
** if no error occurs, make sure Pager.journalMode is not set to
** PAGER_JOURNALMODE_WAL.
**

  void (*xReinit)(DbPage*) /* Function to reinitialize pages */
){
  u8 *pPtr;
  Pager *pPager = 0;       /* Pager object to allocate and return */
  int rc = SQLITE_OK;      /* Return code */
  int tempFile = 0;        /* True for temp files (incl. in-memory files) */
  int memDb = 0;           /* True if this is an in-memory file */

  int memJM = 0;           /* Memory journal mode */



  int readOnly = 0;        /* True if this is a read-only file */
  int journalFileSize;     /* Bytes to allocate for each journal fd */
  char *zPathname = 0;     /* Full path to database file */
  int nPathname = 0;       /* Number of bytes in zPathname */
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
  int pcacheSize = sqlite3PcacheSize();       /* Bytes to allocate for PCache */
  u32 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;  /* Default page size */

  **   - \0
  **
  ** The sqlite3_create_filename() interface and the databaseFilename() utility
  ** that is used by sqlite3_filename_database() and kin also depend on the
  ** specific formatting and order of the various filenames, so if the format
  ** changes here, be sure to change it there as well.
  */
  assert( SQLITE_PTRSIZE==sizeof(Pager*) );
  pPtr = (u8 *)sqlite3MallocZero(
    ROUND8(sizeof(*pPager)) +            /* Pager structure */
    ROUND8(pcacheSize) +                 /* PCache object */
    ROUND8(pVfs->szOsFile) +             /* The main db file */
    journalFileSize * 2 +                /* The two journal files */
    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
    4 +                                  /* Database prefix */
    nPathname + 1 +                      /* database filename */
    nUriByte +                           /* query parameters */
    nPathname + 8 + 1 +                  /* Journal filename */
#ifndef SQLITE_OMIT_WAL
    nPathname + 4 + 1 +                  /* WAL filename */
#endif
    3                                    /* Terminator */
  );
  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
  if( !pPtr ){
    sqlite3DbFree(0, zPathname);
    return SQLITE_NOMEM_BKPT;
  }
  pPager = (Pager*)pPtr;                  pPtr += ROUND8(sizeof(*pPager));
  pPager->pPCache = (PCache*)pPtr;        pPtr += ROUND8(pcacheSize);
  pPager->fd = (sqlite3_file*)pPtr;       pPtr += ROUND8(pVfs->szOsFile);
  pPager->sjfd = (sqlite3_file*)pPtr;     pPtr += journalFileSize;
  pPager->jfd =  (sqlite3_file*)pPtr;     pPtr += journalFileSize;
  assert( EIGHT_BYTE_ALIGNMENT(pPager->jfd) );
  memcpy(pPtr, &pPager, SQLITE_PTRSIZE);  pPtr += SQLITE_PTRSIZE;

  /* Fill in the Pager.zFilename and pPager.zQueryParam fields */
                                          pPtr += 4;  /* Skip zero prefix */
  pPager->zFilename = (char*)pPtr;
  if( nPathname>0 ){
    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname + 1;
    if( zUri ){

  /* Open the pager file.
  */
  if( zFilename && zFilename[0] ){
    int fout = 0;                    /* VFS flags returned by xOpen() */
    rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
    assert( !memDb );

    pPager->memVfs = memJM = (fout&SQLITE_OPEN_MEMORY)!=0;

    readOnly = (fout&SQLITE_OPEN_READONLY)!=0;

    /* If the file was successfully opened for read/write access,
    ** choose a default page size in case we have to create the
    ** database file. The default page size is the maximum of:
    **
    **    + SQLITE_DEFAULT_PAGE_SIZE,

  *ppPager = pPager;
  return SQLITE_OK;
}

/*
** Return the sqlite3_file for the main database given the name
** of the corresponding WAL or Journal name as passed into
** xOpen.
*/
SQLITE_API sqlite3_file *sqlite3_database_file_object(const char *zName){
  Pager *pPager;
  while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
    zName--;
  }

  if( eMode!=eOld ){

    /* Change the journal mode. */
    assert( pPager->eState!=PAGER_ERROR );
    pPager->journalMode = (u8)eMode;

    /* When transitioning from TRUNCATE or PERSIST to any other journal
    ** mode except WAL, unless the pager is in locking_mode=exclusive mode,
    ** delete the journal file.
    */
    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );

/*
** Attempt to take an exclusive lock on the database file. If a PENDING lock
** is obtained instead, immediately release it.
*/
static int pagerExclusiveLock(Pager *pPager){
  int rc;                         /* Return code */
  u8 eOrigLock;                   /* Original lock */

  assert( pPager->eLock>=SHARED_LOCK );
  eOrigLock = pPager->eLock;
  rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    /* If the attempt to grab the exclusive lock failed, release the
    ** pending lock that may have been obtained instead.  */
    pagerUnlockDb(pPager, eOrigLock);
  }

  return rc;
}

/*
** Call sqlite3WalOpen() to open the WAL handle. If the pager is in

** is empty, return 0.
*/
SQLITE_PRIVATE int sqlite3PagerWalFramesize(Pager *pPager){
  assert( pPager->eState>=PAGER_READER );
  return sqlite3WalFramesize(pPager->pWal);
}
#endif

#ifdef SQLITE_USE_SEH
SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager *pPager){
  return sqlite3WalSystemErrno(pPager->pWal);
}
#endif

#endif /* SQLITE_OMIT_DISKIO */

/************** End of pager.c ***********************************************/
/************** Begin file wal.c *********************************************/
/*
** 2010 February 1

/*
** Index numbers for various locking bytes.   WAL_NREADER is the number
** of available reader locks and should be at least 3.  The default
** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
**
** Technically, the various VFSes are free to implement these locks however
** they see fit.  However, compatibility is encouraged so that VFSes can
** interoperate.  The standard implementation used on both unix and windows
** is for the index number to indicate a byte offset into the
** WalCkptInfo.aLock[] array in the wal-index header.  In other words, all
** locks are on the shm file.  The WALINDEX_LOCK_OFFSET constant (which
** should be 120) is the location in the shm file for the first locking
** byte.
*/
#define WAL_WRITE_LOCK         0

** never be read or written.
**
** There is one entry in aReadMark[] for each reader lock.  If a reader
** holds read-lock K, then the value in aReadMark[K] is no greater than
** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
** for any aReadMark[] means that entry is unused.  aReadMark[0] is
** a special case; its value is never used and it exists as a place-holder
** to avoid having to offset aReadMark[] indexes by one.  Readers holding
** WAL_READ_LOCK(0) always ignore the entire WAL and read all content
** directly from the database.
**
** The value of aReadMark[K] may only be changed by a thread that
** is holding an exclusive lock on WAL_READ_LOCK(K).  Thus, the value of
** aReadMark[K] cannot changed while there is a reader is using that mark
** since the reader will be holding a shared lock on WAL_READ_LOCK(K).

  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
  u8 bShmUnreliable;         /* SHM content is read-only and unreliable */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  u32 minFrame;              /* Ignore wal frames before this one */
  u32 iReCksum;              /* On commit, recalculate checksums from here */
  const char *zWalName;      /* Name of WAL file */
  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_USE_SEH
  u32 lockMask;              /* Mask of locks held */
  void *pFree;               /* Pointer to sqlite3_free() if exception thrown */
  u32 *pWiValue;             /* Value to write into apWiData[iWiPg] */
  int iWiPg;                 /* Write pWiValue into apWiData[iWiPg] */
  int iSysErrno;             /* System error code following exception */
#endif
#ifdef SQLITE_DEBUG
  int nSehTry;               /* Number of nested SEH_TRY{} blocks */
  u8 lockError;              /* True if a locking error has occurred */
#endif
#ifdef SQLITE_ENABLE_SNAPSHOT
  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  sqlite3 *db;

*/
#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))

/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
#define WALINDEX_PGSZ   (                                         \
    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
)

/*
** Structured Exception Handling (SEH) is a Windows-specific technique
** for catching exceptions raised while accessing memory-mapped files.
**
** The -DSQLITE_USE_SEH compile-time option means to use SEH to catch and
** deal with system-level errors that arise during WAL -shm file processing.
** Without this compile-time option, any system-level faults that appear
** while accessing the memory-mapped -shm file will cause a process-wide
** signal to be deliver, which will more than likely cause the entire
** process to exit.
*/
#ifdef SQLITE_USE_SEH
#include <Windows.h>

/* Beginning of a block of code in which an exception might occur */
# define SEH_TRY    __try { \
   assert( walAssertLockmask(pWal) && pWal->nSehTry==0 ); \
   VVA_ONLY(pWal->nSehTry++);

/* The end of a block of code in which an exception might occur */
# define SEH_EXCEPT(X) \
   VVA_ONLY(pWal->nSehTry--); \
   assert( pWal->nSehTry==0 ); \
   } __except( sehExceptionFilter(pWal, GetExceptionCode(), GetExceptionInformation() ) ){ X }

/* Simulate a memory-mapping fault in the -shm file for testing purposes */
# define SEH_INJECT_FAULT sehInjectFault(pWal)

/*
** The second argument is the return value of GetExceptionCode() for the
** current exception. Return EXCEPTION_EXECUTE_HANDLER if the exception code
** indicates that the exception may have been caused by accessing the *-shm
** file mapping. Or EXCEPTION_CONTINUE_SEARCH otherwise.
*/
static int sehExceptionFilter(Wal *pWal, int eCode, EXCEPTION_POINTERS *p){
  VVA_ONLY(pWal->nSehTry--);
  if( eCode==EXCEPTION_IN_PAGE_ERROR ){
    if( p && p->ExceptionRecord && p->ExceptionRecord->NumberParameters>=3 ){
      /* From MSDN: For this type of exception, the first element of the
      ** ExceptionInformation[] array is a read-write flag - 0 if the exception
      ** was thrown while reading, 1 if while writing. The second element is
      ** the virtual address being accessed. The "third array element specifies
      ** the underlying NTSTATUS code that resulted in the exception". */
      pWal->iSysErrno = (int)p->ExceptionRecord->ExceptionInformation[2];
    }
    return EXCEPTION_EXECUTE_HANDLER;
  }
  return EXCEPTION_CONTINUE_SEARCH;
}

/*
** If one is configured, invoke the xTestCallback callback with 650 as
** the argument. If it returns true, throw the same exception that is
** thrown by the system if the *-shm file mapping is accessed after it
** has been invalidated.
*/
static void sehInjectFault(Wal *pWal){
  int res;
  assert( pWal->nSehTry>0 );

  res = sqlite3FaultSim(650);
  if( res!=0 ){
    ULONG_PTR aArg[3];
    aArg[0] = 0;
    aArg[1] = 0;
    aArg[2] = (ULONG_PTR)res;
    RaiseException(EXCEPTION_IN_PAGE_ERROR, 0, 3, (const ULONG_PTR*)aArg);
  }
}

/*
** There are two ways to use this macro. To set a pointer to be freed
** if an exception is thrown:
**
**   SEH_FREE_ON_ERROR(0, pPtr);
**
** and to cancel the same:
**
**   SEH_FREE_ON_ERROR(pPtr, 0);
**
** In the first case, there must not already be a pointer registered to
** be freed. In the second case, pPtr must be the registered pointer.
*/
#define SEH_FREE_ON_ERROR(X,Y) \
  assert( (X==0 || Y==0) && pWal->pFree==X ); pWal->pFree = Y

/*
** There are two ways to use this macro. To arrange for pWal->apWiData[iPg]
** to be set to pValue if an exception is thrown:
**
**   SEH_SET_ON_ERROR(iPg, pValue);
**
** and to cancel the same:
**
**   SEH_SET_ON_ERROR(0, 0);
*/
#define SEH_SET_ON_ERROR(X,Y)  pWal->iWiPg = X; pWal->pWiValue = Y

#else
# define SEH_TRY          VVA_ONLY(pWal->nSehTry++);
# define SEH_EXCEPT(X)    VVA_ONLY(pWal->nSehTry--); assert( pWal->nSehTry==0 );
# define SEH_INJECT_FAULT assert( pWal->nSehTry>0 );
# define SEH_FREE_ON_ERROR(X,Y)
# define SEH_SET_ON_ERROR(X,Y)
#endif /* ifdef SQLITE_USE_SEH */


/*
** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
** numbered from zero.
**
** If the wal-index is currently smaller the iPage pages then the size

  return rc;
}
static int walIndexPage(
  Wal *pWal,               /* The WAL context */
  int iPage,               /* The page we seek */
  volatile u32 **ppPage    /* Write the page pointer here */
){
  SEH_INJECT_FAULT;
  if( pWal->nWiData<=iPage || (*ppPage = pWal->apWiData[iPage])==0 ){
    return walIndexPageRealloc(pWal, iPage, ppPage);
  }
  return SQLITE_OK;
}

/*
** Return a pointer to the WalCkptInfo structure in the wal-index.
*/
static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );
  SEH_INJECT_FAULT;
  return (volatile WalCkptInfo*)&(pWal->apWiData[0][sizeof(WalIndexHdr)/2]);
}

/*
** Return a pointer to the WalIndexHdr structure in the wal-index.
*/
static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );
  SEH_INJECT_FAULT;
  return (volatile WalIndexHdr*)pWal->apWiData[0];
}

/*
** The argument to this macro must be of type u32. On a little-endian
** architecture, it returns the u32 value that results from interpreting
** the 4 bytes as a big-endian value. On a big-endian architecture, it

  /* A frame is only valid if the salt values in the frame-header
  ** match the salt values in the wal-header.
  */
  if( memcmp(&pWal->hdr.aSalt, &aFrame[8], 8)!=0 ){
    return 0;
  }

  /* A frame is only valid if the page number is greater than zero.
  */
  pgno = sqlite3Get4byte(&aFrame[0]);
  if( pgno==0 ){
    return 0;
  }

  /* A frame is only valid if a checksum of the WAL header,
  ** all prior frames, the first 16 bytes of this frame-header,
  ** and the frame-data matches the checksum in the last 8
  ** bytes of this frame-header.
  */
  nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
  walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
  walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
  if( aCksum[0]!=sqlite3Get4byte(&aFrame[16])

  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
            walLockName(lockIdx), rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
#ifdef SQLITE_USE_SEH
  if( rc==SQLITE_OK ) pWal->lockMask |= (1 << lockIdx);
#endif
  return rc;
}
static void walUnlockShared(Wal *pWal, int lockIdx){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
#ifdef SQLITE_USE_SEH
  pWal->lockMask &= ~(1 << lockIdx);
#endif
  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
}
static int walLockExclusive(Wal *pWal, int lockIdx, int n){
  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
            walLockName(lockIdx), n, rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
#ifdef SQLITE_USE_SEH
  if( rc==SQLITE_OK ){
    pWal->lockMask |= (((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
  }
#endif
  return rc;
}
static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
#ifdef SQLITE_USE_SEH
  pWal->lockMask &= ~(((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
#endif
  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
             walLockName(lockIdx), n));
}

/*
** Compute a hash on a page number.  The resulting hash value must land
** between 0 and (HASHTABLE_NSLOT-1).  The walHashNext() function advances

}

/*
** Return the page number associated with frame iFrame in this WAL.
*/
static u32 walFramePgno(Wal *pWal, u32 iFrame){
  int iHash = walFramePage(iFrame);
  SEH_INJECT_FAULT;
  if( iHash==0 ){
    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
  }
  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
}

/*

      rc = SQLITE_CANTOPEN_BKPT;
      goto finished;
    }

    /* Malloc a buffer to read frames into. */
    szFrame = szPage + WAL_FRAME_HDRSIZE;
    aFrame = (u8 *)sqlite3_malloc64(szFrame + WALINDEX_PGSZ);
    SEH_FREE_ON_ERROR(0, aFrame);
    if( !aFrame ){
      rc = SQLITE_NOMEM_BKPT;
      goto recovery_error;
    }
    aData = &aFrame[WAL_FRAME_HDRSIZE];
    aPrivate = (u32*)&aData[szPage];

    /* Read all frames from the log file. */
    iLastFrame = (nSize - WAL_HDRSIZE) / szFrame;
    for(iPg=0; iPg<=(u32)walFramePage(iLastFrame); iPg++){
      u32 *aShare;
      u32 iFrame;                 /* Index of last frame read */
      u32 iLast = MIN(iLastFrame, HASHTABLE_NPAGE_ONE+iPg*HASHTABLE_NPAGE);
      u32 iFirst = 1 + (iPg==0?0:HASHTABLE_NPAGE_ONE+(iPg-1)*HASHTABLE_NPAGE);
      u32 nHdr, nHdr32;
      rc = walIndexPage(pWal, iPg, (volatile u32**)&aShare);
      assert( aShare!=0 || rc!=SQLITE_OK );
      if( aShare==0 ) break;
      SEH_SET_ON_ERROR(iPg, aShare);
      pWal->apWiData[iPg] = aPrivate;

      for(iFrame=iFirst; iFrame<=iLast; iFrame++){
        i64 iOffset = walFrameOffset(iFrame, szPage);
        u32 pgno;                 /* Database page number for frame */
        u32 nTruncate;            /* dbsize field from frame header */

          testcase( szPage<=32768 );
          testcase( szPage>=65536 );
          aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
          aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
        }
      }
      pWal->apWiData[iPg] = aShare;
      SEH_SET_ON_ERROR(0,0);
      nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
      nHdr32 = nHdr / sizeof(u32);
#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
      /* Memcpy() should work fine here, on all reasonable implementations.
      ** Technically, memcpy() might change the destination to some
      ** intermediate value before setting to the final value, and that might
      ** cause a concurrent reader to malfunction.  Memcpy() is allowed to

            ** the value needs to be changed, that means it is not being
            ** accessed concurrently. */
            aShare[i] = aPrivate[i];
          }
        }
      }
#endif
      SEH_INJECT_FAULT;
      if( iFrame<=iLast ) break;
    }

    SEH_FREE_ON_ERROR(aFrame, 0);
    sqlite3_free(aFrame);
  }

finished:
  if( rc==SQLITE_OK ){
    volatile WalCkptInfo *pInfo;
    int i;

      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
      if( rc==SQLITE_OK ){
        if( i==1 && pWal->hdr.mxFrame ){
          pInfo->aReadMark[i] = pWal->hdr.mxFrame;
        }else{
          pInfo->aReadMark[i] = READMARK_NOT_USED;
        }
        SEH_INJECT_FAULT;
        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
      }else if( rc!=SQLITE_BUSY ){
        goto recovery_error;
      }
    }

    /* If more than one frame was recovered from the log file, report an

    *ppWal = pRet;
    WALTRACE(("WAL%d: opened\n", pRet));
  }
  return rc;
}

/*
** Change the size to which the WAL file is truncated on each reset.
*/
SQLITE_PRIVATE void sqlite3WalLimit(Wal *pWal, i64 iLimit){
  if( pWal ) pWal->mxWalSize = iLimit;
}

/*
** Find the smallest page number out of all pages held in the WAL that

  iLast = pWal->hdr.mxFrame;

  /* Allocate space for the WalIterator object. */
  nSegment = walFramePage(iLast) + 1;
  nByte = sizeof(WalIterator)
        + (nSegment-1)*sizeof(struct WalSegment)
        + iLast*sizeof(ht_slot);
  p = (WalIterator *)sqlite3_malloc64(nByte
      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
  );
  if( !p ){
    return SQLITE_NOMEM_BKPT;
  }
  memset(p, 0, nByte);
  p->nSegment = nSegment;




  aTmp = (ht_slot*)&(((u8*)p)[nByte]);





  SEH_FREE_ON_ERROR(0, p);
  for(i=walFramePage(nBackfill+1); rc==SQLITE_OK && i<nSegment; i++){
    WalHashLoc sLoc;

    rc = walHashGet(pWal, i, &sLoc);
    if( rc==SQLITE_OK ){
      int j;                      /* Counter variable */
      int nEntry;                 /* Number of entries in this segment */

      walMergesort((u32 *)sLoc.aPgno, aTmp, aIndex, &nEntry);
      p->aSegment[i].iZero = sLoc.iZero;
      p->aSegment[i].nEntry = nEntry;
      p->aSegment[i].aIndex = aIndex;
      p->aSegment[i].aPgno = (u32 *)sLoc.aPgno;
    }
  }


  if( rc!=SQLITE_OK ){
    SEH_FREE_ON_ERROR(p, 0);
    walIteratorFree(p);
    p = 0;
  }
  *pp = p;
  return rc;
}

    ** safe to write into the database.  Frames beyond mxSafeFrame might
    ** overwrite database pages that are in use by active readers and thus
    ** cannot be backfilled from the WAL.
    */
    mxSafeFrame = pWal->hdr.mxFrame;
    mxPage = pWal->hdr.nPage;
    for(i=1; i<WAL_NREADER; i++){
      u32 y = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
      if( mxSafeFrame>y ){
        assert( y<=pWal->hdr.mxFrame );
        rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
        if( rc==SQLITE_OK ){
          u32 iMark = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
          AtomicStore(pInfo->aReadMark+i, iMark); SEH_INJECT_FAULT;
          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
        }else if( rc==SQLITE_BUSY ){
          mxSafeFrame = y;
          xBusy = 0;
        }else{
          goto walcheckpoint_out;
        }
      }
    }

    /* Allocate the iterator */
    if( pInfo->nBackfill<mxSafeFrame ){
      rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
      assert( rc==SQLITE_OK || pIter==0 );
    }

    if( pIter
     && (rc = walBusyLock(pWal,xBusy,pBusyArg,WAL_READ_LOCK(0),1))==SQLITE_OK
    ){
      u32 nBackfill = pInfo->nBackfill;

      pInfo->nBackfillAttempted = mxSafeFrame; SEH_INJECT_FAULT;

      /* Sync the WAL to disk */
      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));

      /* If the database may grow as a result of this checkpoint, hint
      ** about the eventual size of the db file to the VFS layer.
      */

      }

      /* Iterate through the contents of the WAL, copying data to the db file */
      while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
        i64 iOffset;
        assert( walFramePgno(pWal, iFrame)==iDbpage );
        SEH_INJECT_FAULT;
        if( AtomicLoad(&db->u1.isInterrupted) ){
          rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
          break;
        }
        if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){
          continue;
        }

          testcase( IS_BIG_INT(szDb) );
          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
          if( rc==SQLITE_OK ){
            rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
          }
        }
        if( rc==SQLITE_OK ){
          AtomicStore(&pInfo->nBackfill, mxSafeFrame); SEH_INJECT_FAULT;
        }
      }

      /* Release the reader lock held while backfilling */
      walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
    }

  /* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
  ** entire wal file has been copied into the database file, then block
  ** until all readers have finished using the wal file. This ensures that
  ** the next process to write to the database restarts the wal file.
  */
  if( rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
    assert( pWal->writeLock );
    SEH_INJECT_FAULT;
    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
      rc = SQLITE_BUSY;
    }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
      u32 salt1;
      sqlite3_randomness(4, &salt1);
      assert( pInfo->nBackfill==pWal->hdr.mxFrame );
      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);

        }
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }
    }
  }

 walcheckpoint_out:
  SEH_FREE_ON_ERROR(pIter, 0);
  walIteratorFree(pIter);
  return rc;
}

/*
** If the WAL file is currently larger than nMax bytes in size, truncate
** it to exactly nMax bytes. If an error occurs while doing so, ignore it.

  }
  sqlite3EndBenignMalloc();
  if( rx ){
    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
  }
}

#ifdef SQLITE_USE_SEH
/*
** This is the "standard" exception handler used in a few places to handle
** an exception thrown by reading from the *-shm mapping after it has become
** invalid in SQLITE_USE_SEH builds. It is used as follows:
**
**   SEH_TRY { ... }
**   SEH_EXCEPT( rc = walHandleException(pWal); )
**
** This function does three things:
**
**   1) Determines the locks that should be held, based on the contents of
**      the Wal.readLock, Wal.writeLock and Wal.ckptLock variables. All other
**      held locks are assumed to be transient locks that would have been
**      released had the exception not been thrown and are dropped.
**
**   2) Frees the pointer at Wal.pFree, if any, using sqlite3_free().
**
**   3) Set pWal->apWiData[pWal->iWiPg] to pWal->pWiValue if not NULL
**
**   4) Returns SQLITE_IOERR.
*/
static int walHandleException(Wal *pWal){
  if( pWal->exclusiveMode==0 ){
    static const int S = 1;
    static const int E = (1<<SQLITE_SHM_NLOCK);
    int ii;
    u32 mUnlock = pWal->lockMask & ~(
        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
        | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
        | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
        );
    for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
      if( (S<<ii) & mUnlock ) walUnlockShared(pWal, ii);
      if( (E<<ii) & mUnlock ) walUnlockExclusive(pWal, ii, 1);
    }
  }
  sqlite3_free(pWal->pFree);
  pWal->pFree = 0;
  if( pWal->pWiValue ){
    pWal->apWiData[pWal->iWiPg] = pWal->pWiValue;
    pWal->pWiValue = 0;
  }
  return SQLITE_IOERR_IN_PAGE;
}

/*
** Assert that the Wal.lockMask mask, which indicates the locks held
** by the connenction, is consistent with the Wal.readLock, Wal.writeLock
** and Wal.ckptLock variables. To be used as:
**
**   assert( walAssertLockmask(pWal) );
*/
static int walAssertLockmask(Wal *pWal){
  if( pWal->exclusiveMode==0 ){
    static const int S = 1;
    static const int E = (1<<SQLITE_SHM_NLOCK);
    u32 mExpect = (
        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
      | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
      | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
#ifdef SQLITE_ENABLE_SNAPSHOT
      | (pWal->pSnapshot ? (pWal->lockMask & (1 << WAL_CKPT_LOCK)) : 0)
#endif
    );
    assert( mExpect==pWal->lockMask );
  }
  return 1;
}

/*
** Return and zero the "system error" field set when an
** EXCEPTION_IN_PAGE_ERROR exception is caught.
*/
SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal *pWal){
  int iRet = 0;
  if( pWal ){
    iRet = pWal->iSysErrno;
    pWal->iSysErrno = 0;
  }
  return iRet;
}

#else
# define walAssertLockmask(x) 1
#endif /* ifdef SQLITE_USE_SEH */

/*
** Close a connection to a log file.
*/
SQLITE_PRIVATE int sqlite3WalClose(
  Wal *pWal,                      /* Wal to close */
  sqlite3 *db,                    /* For interrupt flag */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  int nBuf,
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */

    assert( walAssertLockmask(pWal) );

    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **

      if( rc==SQLITE_OK ){
        int bPersist = -1;
        sqlite3OsFileControlHint(
            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
        );
        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsynced (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate

  ** There are two copies of the header at the beginning of the wal-index.
  ** When reading, read [0] first then [1].  Writes are in the reverse order.
  ** Memory barriers are used to prevent the compiler or the hardware from
  ** reordering the reads and writes.  TSAN and similar tools can sometimes
  ** give false-positive warnings about these accesses because the tools do not
  ** account for the double-read and the memory barrier. The use of mutexes
  ** here would be problematic as the memory being accessed is potentially
  ** shared among multiple processes and not all mutex implementations work
  ** reliably in that environment.
  */
  aHdr = walIndexHdr(pWal);
  memcpy(&h1, (void *)&aHdr[0], sizeof(h1)); /* Possible TSAN false-positive */
  walShmBarrier(pWal);
  memcpy(&h2, (void *)&aHdr[1], sizeof(h2));

      return walBeginShmUnreliable(pWal, pChanged);
    }
  }

  assert( pWal->nWiData>0 );
  assert( pWal->apWiData[0]!=0 );
  pInfo = walCkptInfo(pWal);
  SEH_INJECT_FAULT;
  if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
#ifdef SQLITE_ENABLE_SNAPSHOT
   && (pWal->pSnapshot==0 || pWal->hdr.mxFrame==0)
#endif
  ){
    /* The WAL has been completely backfilled (or it is empty).
    ** and can be safely ignored.

  mxFrame = pWal->hdr.mxFrame;
#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
    mxFrame = pWal->pSnapshot->mxFrame;
  }
#endif
  for(i=1; i<WAL_NREADER; i++){
    u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
    if( mxReadMark<=thisMark && thisMark<=mxFrame ){
      assert( thisMark!=READMARK_NOT_USED );
      mxReadMark = thisMark;
      mxI = i;
    }
  }
  if( (pWal->readOnly & WAL_SHM_RDONLY)==0

  ** A) on the basis that there is a newer version (version B) of the same
  ** page later in the wal file. But if version B happens to like past
  ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
  ** that it can read version A from the database file. However, since
  ** we can guarantee that the checkpointer that set nBackfill could not
  ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
  */
  pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
  walShmBarrier(pWal);
  if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
   || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
  ){
    walUnlockShared(pWal, WAL_READ_LOCK(mxI));
    return WAL_RETRY;
  }else{
    assert( mxReadMark<=pWal->hdr.mxFrame );
    pWal->readLock = (i16)mxI;
  }
  return rc;
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** This function does the work of sqlite3WalSnapshotRecover().
*/
static int walSnapshotRecover(
  Wal *pWal,                      /* WAL handle */
  void *pBuf1,                    /* Temp buffer pWal->szPage bytes in size */
  void *pBuf2                     /* Temp buffer pWal->szPage bytes in size */
){
  int szPage = (int)pWal->szPage;
  int rc;
  i64 szDb;                       /* Size of db file in bytes */

  rc = sqlite3OsFileSize(pWal->pDbFd, &szDb);
  if( rc==SQLITE_OK ){
    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
    u32 i = pInfo->nBackfillAttempted;
    for(i=pInfo->nBackfillAttempted; i>AtomicLoad(&pInfo->nBackfill); i--){
      WalHashLoc sLoc;          /* Hash table location */
      u32 pgno;                 /* Page number in db file */
      i64 iDbOff;               /* Offset of db file entry */
      i64 iWalOff;              /* Offset of wal file entry */

      rc = walHashGet(pWal, walFramePage(i), &sLoc);
      if( rc!=SQLITE_OK ) break;
      assert( i - sLoc.iZero - 1 >=0 );
      pgno = sLoc.aPgno[i-sLoc.iZero-1];
      iDbOff = (i64)(pgno-1) * szPage;

      if( iDbOff+szPage<=szDb ){
        iWalOff = walFrameOffset(i, szPage) + WAL_FRAME_HDRSIZE;
        rc = sqlite3OsRead(pWal->pWalFd, pBuf1, szPage, iWalOff);

        if( rc==SQLITE_OK ){
          rc = sqlite3OsRead(pWal->pDbFd, pBuf2, szPage, iDbOff);
        }

        if( rc!=SQLITE_OK || 0==memcmp(pBuf1, pBuf2, szPage) ){
          break;
        }
      }

      pInfo->nBackfillAttempted = i-1;
    }
  }

  return rc;
}

/*
** Attempt to reduce the value of the WalCkptInfo.nBackfillAttempted
** variable so that older snapshots can be accessed. To do this, loop
** through all wal frames from nBackfillAttempted to (nBackfill+1),
** comparing their content to the corresponding page with the database
** file, if any. Set nBackfillAttempted to the frame number of the
** first frame for which the wal file content matches the db file.

*/
SQLITE_PRIVATE int sqlite3WalSnapshotRecover(Wal *pWal){
  int rc;

  assert( pWal->readLock>=0 );
  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
  if( rc==SQLITE_OK ){






    void *pBuf1 = sqlite3_malloc(pWal->szPage);
    void *pBuf2 = sqlite3_malloc(pWal->szPage);
    if( pBuf1==0 || pBuf2==0 ){
      rc = SQLITE_NOMEM;
    }else{






      pWal->ckptLock = 1;





      SEH_TRY {



        rc = walSnapshotRecover(pWal, pBuf1, pBuf2);


      }
      SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )




      pWal->ckptLock = 0;

    }


    sqlite3_free(pBuf1);
    sqlite3_free(pBuf2);

    walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
  }

  return rc;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

/*
** This function does the work of sqlite3WalBeginReadTransaction() (see
** below). That function simply calls this one inside an SEH_TRY{...} block.










*/
static int walBeginReadTransaction(Wal *pWal, int *pChanged){
  int rc;                         /* Return code */
  int cnt = 0;                    /* Number of TryBeginRead attempts */
#ifdef SQLITE_ENABLE_SNAPSHOT
  int ckptLock = 0;
  int bChanged = 0;
  WalIndexHdr *pSnapshot = pWal->pSnapshot;
#endif

  assert( pWal->ckptLock==0 );
  assert( pWal->nSehTry>0 );

#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pSnapshot ){
    if( memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      bChanged = 1;
    }

    (void)walEnableBlocking(pWal);
    rc = walLockShared(pWal, WAL_CKPT_LOCK);
    walDisableBlocking(pWal);

    if( rc!=SQLITE_OK ){
      return rc;
    }
    ckptLock = 1;
  }
#endif

  do{
    rc = walTryBeginRead(pWal, pChanged, 0, ++cnt);
  }while( rc==WAL_RETRY );
  testcase( (rc&0xff)==SQLITE_BUSY );

      if( rc!=SQLITE_OK ){
        sqlite3WalEndReadTransaction(pWal);
      }
    }
  }

  /* Release the shared CKPT lock obtained above. */
  if( ckptLock ){
    assert( pSnapshot );
    walUnlockShared(pWal, WAL_CKPT_LOCK);

  }
#endif
  return rc;
}

/*
** Begin a read transaction on the database.
**
** This routine used to be called sqlite3OpenSnapshot() and with good reason:
** it takes a snapshot of the state of the WAL and wal-index for the current
** instant in time.  The current thread will continue to use this snapshot.
** Other threads might append new content to the WAL and wal-index but
** that extra content is ignored by the current thread.
**
** If the database contents have changes since the previous read
** transaction, then *pChanged is set to 1 before returning.  The
** Pager layer will use this to know that its cache is stale and
** needs to be flushed.
*/
SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){
  int rc;
  SEH_TRY {
    rc = walBeginReadTransaction(pWal, pChanged);
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}

/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/
SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal){
  sqlite3WalEndWriteTransaction(pWal);

** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
*/
static int walFindFrame(
  Wal *pWal,                      /* WAL handle */
  Pgno pgno,                      /* Database page number to read data for */
  u32 *piRead                     /* OUT: Frame number (or zero) */
){
  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
  u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
  int iHash;                      /* Used to loop through N hash tables */

    rc = walHashGet(pWal, iHash, &sLoc);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    nCollide = HASHTABLE_NSLOT;
    iKey = walHash(pgno);
    SEH_INJECT_FAULT;
    while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
      u32 iFrame = iH + sLoc.iZero;
      if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
        assert( iFrame>iRead || CORRUPT_DB );
        iRead = iFrame;
      }
      if( (nCollide--)==0 ){

    assert( iRead==iRead2 );
  }
#endif

  *piRead = iRead;
  return SQLITE_OK;
}

/*
** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
**
** The difference between this function and walFindFrame() is that this
** function wraps walFindFrame() in an SEH_TRY{...} block.
*/
SQLITE_PRIVATE int sqlite3WalFindFrame(
  Wal *pWal,                      /* WAL handle */
  Pgno pgno,                      /* Database page number to read data for */
  u32 *piRead                     /* OUT: Frame number (or zero) */
){
  int rc;
  SEH_TRY {
    rc = walFindFrame(pWal, pgno, piRead);
  }
  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  return rc;
}

/*
** Read the contents of frame iRead from the wal file into buffer pOut
** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
** error code otherwise.
*/
SQLITE_PRIVATE int sqlite3WalReadFrame(

  }
  pWal->writeLock = 1;

  /* If another connection has written to the database file since the
  ** time the read transaction on this connection was started, then
  ** the write is disallowed.
  */
  SEH_TRY {
    if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){


      rc = SQLITE_BUSY_SNAPSHOT;
    }
  }
  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )

  if( rc!=SQLITE_OK ){
    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
    pWal->writeLock = 0;
  }
  return rc;
}

/*
** End a write transaction.  The commit has already been done.  This
** routine merely releases the lock.
*/

*/
SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  if( ALWAYS(pWal->writeLock) ){
    Pgno iMax = pWal->hdr.mxFrame;
    Pgno iFrame;

    SEH_TRY {
      /* Restore the clients cache of the wal-index header to the state it
      ** was in before the client began writing to the database.
      */
      memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));

      for(iFrame=pWal->hdr.mxFrame+1;
          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax;
          iFrame++
      ){
        /* This call cannot fail. Unless the page for which the page number
        ** is passed as the second argument is (a) in the cache and
        ** (b) has an outstanding reference, then xUndo is either a no-op
        ** (if (a) is false) or simply expels the page from the cache (if (b)
        ** is false).
        **
        ** If the upper layer is doing a rollback, it is guaranteed that there
        ** are no outstanding references to any page other than page 1. And
        ** page 1 is never written to the log until the transaction is
        ** committed. As a result, the call to xUndo may not fail.
        */
        assert( walFramePgno(pWal, iFrame)!=1 );
        rc = xUndo(pUndoCtx, walFramePgno(pWal, iFrame));
      }
      if( iMax!=pWal->hdr.mxFrame ) walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }
  return rc;
}

/*
** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32
** values. This function populates the array with values required to

    aWalData[3] = pWal->nCkpt;
  }

  if( aWalData[0]<pWal->hdr.mxFrame ){
    pWal->hdr.mxFrame = aWalData[0];
    pWal->hdr.aFrameCksum[0] = aWalData[1];
    pWal->hdr.aFrameCksum[1] = aWalData[2];
    SEH_TRY {
      walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }

  return rc;
}

/*
** This function is called just before writing a set of frames to the log

  return rc;
}

/*
** Write a set of frames to the log. The caller must hold the write-lock
** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
*/
static int walFrames(
  Wal *pWal,                      /* Wal handle to write to */
  int szPage,                     /* Database page-size in bytes */
  PgHdr *pList,                   /* List of dirty pages to write */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){

    /* Check if this page has already been written into the wal file by
    ** the current transaction. If so, overwrite the existing frame and
    ** set Wal.writeLock to WAL_WRITELOCK_RECKSUM - indicating that
    ** checksums must be recomputed when the transaction is committed.  */
    if( iFirst && (p->pDirty || isCommit==0) ){
      u32 iWrite = 0;
      VVA_ONLY(rc =) walFindFrame(pWal, p->pgno, &iWrite);
      assert( rc==SQLITE_OK || iWrite==0 );
      if( iWrite>=iFirst ){
        i64 iOff = walFrameOffset(iWrite, szPage) + WAL_FRAME_HDRSIZE;
        void *pData;
        if( pWal->iReCksum==0 || iWrite<pWal->iReCksum ){
          pWal->iReCksum = iWrite;
        }

      pWal->iCallback = iFrame;
    }
  }

  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
  return rc;
}

/*
** Write a set of frames to the log. The caller must hold the write-lock
** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
**
** The difference between this function and walFrames() is that this
** function wraps walFrames() in an SEH_TRY{...} block.
*/
SQLITE_PRIVATE int sqlite3WalFrames(
  Wal *pWal,                      /* Wal handle to write to */
  int szPage,                     /* Database page-size in bytes */
  PgHdr *pList,                   /* List of dirty pages to write */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
  int rc;
  SEH_TRY {
    rc = walFrames(pWal, szPage, pList, nTruncate, isCommit, sync_flags);
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}

/*
** This routine is called to implement sqlite3_wal_checkpoint() and
** related interfaces.
**
** Obtain a CHECKPOINT lock and then backfill as much information as
** we can from WAL into the database.

        rc = SQLITE_OK;
      }
    }
  }


  /* Read the wal-index header. */
  SEH_TRY {
    if( rc==SQLITE_OK ){
      walDisableBlocking(pWal);
      rc = walIndexReadHdr(pWal, &isChanged);
      (void)walEnableBlocking(pWal);
      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
      }
    }

    /* Copy data from the log to the database file. */
    if( rc==SQLITE_OK ){

      if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
      }

      /* If no error occurred, set the output variables. */
      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
        if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;
        SEH_INJECT_FAULT;
        if( pnCkpt ) *pnCkpt = (int)(walCkptInfo(pWal)->nBackfill);
      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )

  if( isChanged ){
    /* If a new wal-index header was loaded before the checkpoint was
    ** performed, then the pager-cache associated with pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.

  /* pWal->readLock is usually set, but might be -1 if there was a
  ** prior error while attempting to acquire are read-lock. This cannot
  ** happen if the connection is actually in exclusive mode (as no xShmLock
  ** locks are taken in this case). Nor should the pager attempt to
  ** upgrade to exclusive-mode following such an error.
  */
#ifndef SQLITE_USE_SEH
  assert( pWal->readLock>=0 || pWal->lockError );
#endif
  assert( pWal->readLock>=0 || (op<=0 && pWal->exclusiveMode==0) );

  if( op==0 ){
    if( pWal->exclusiveMode!=WAL_NORMAL_MODE ){
      pWal->exclusiveMode = WAL_NORMAL_MODE;
      if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;

** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
** lock is released before returning.
*/
SQLITE_PRIVATE int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
  int rc;
  SEH_TRY {
    rc = walLockShared(pWal, WAL_CKPT_LOCK);
    if( rc==SQLITE_OK ){
      WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
      if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
       || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted
      ){
        rc = SQLITE_ERROR_SNAPSHOT;
        walUnlockShared(pWal, WAL_CKPT_LOCK);
      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}

/*
** Release a lock obtained by an earlier successful call to
** sqlite3WalSnapshotCheck().
*/

** allows a 64-bit integer to be encoded in 9 bytes.
**
**    0x00                      becomes  0x00000000
**    0x7f                      becomes  0x0000007f
**    0x81 0x00                 becomes  0x00000080
**    0x82 0x00                 becomes  0x00000100
**    0x80 0x7f                 becomes  0x0000007f
**    0x81 0x91 0xd1 0xac 0x78  becomes  0x12345678
**    0x81 0x81 0x81 0x81 0x01  becomes  0x10204081
**
** Variable length integers are used for rowids and to hold the number of
** bytes of key and data in a btree cell.
**
** The content of a cell looks like this:
**

#define PTF_LEAF      0x08

/*
** An instance of this object stores information about each a single database
** page that has been loaded into memory.  The information in this object
** is derived from the raw on-disk page content.
**
** As each database page is loaded into memory, the pager allocates an
** instance of this object and zeros the first 8 bytes.  (This is the
** "extra" information associated with each page of the pager.)
**
** Access to all fields of this structure is controlled by the mutex
** stored in MemPage.pBt->mutex.
*/
struct MemPage {

/*
** Legal values for BtCursor.curFlags
*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing to the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */
#define BTCF_Pinned       0x40   /* Cursor is busy and cannot be moved */

/*
** Potential values for BtCursor.eState.
**

#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte

/*
** get2byteAligned(), unlike get2byte(), requires that its argument point to a
** two-byte aligned address.  get2byteAligned() is only used for accessing the
** cell addresses in a btree header.
*/
#if SQLITE_BYTEORDER==4321
# define get2byteAligned(x)  (*(u16*)(x))
#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4008000
# define get2byteAligned(x)  __builtin_bswap16(*(u16*)(x))
#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300

** connection.  This is needed (for example) prior to parsing
** a statement since we will be comparing table and column names
** against all schemas and we do not want those schemas being
** reset out from under us.
**
** There is a corresponding leave-all procedures.
**
** Enter the mutexes in ascending order by BtShared pointer address
** to avoid the possibility of deadlock when two threads with
** two or more btrees in common both try to lock all their btrees
** at the same instant.
*/
static void SQLITE_NOINLINE btreeEnterAll(sqlite3 *db){
  int i;
  int skipOk = 1;

# endif
#endif /* ifndef SQLITE_OMIT_INCRBLOB */

#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */

/************** End of btmutex.c *********************************************/
/************** Begin file btree.c *******************************************/

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.

static void ptrmapPutOvflPtr(MemPage *pPage, MemPage *pSrc, u8 *pCell,int *pRC){
  CellInfo info;
  if( *pRC ) return;
  assert( pCell!=0 );
  pPage->xParseCell(pPage, pCell, &info);
  if( info.nLocal<info.nPayload ){
    Pgno ovfl;
    if( SQLITE_OVERFLOW(pSrc->aDataEnd, pCell, pCell+info.nLocal) ){
      testcase( pSrc!=pPage );
      *pRC = SQLITE_CORRUPT_BKPT;
      return;
    }
    ovfl = get4byte(&pCell[info.nSize-4]);
    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
  }

  }

  cbrk = usableSize;
  iCellLast = usableSize - 4;
  iCellStart = get2byte(&data[hdr+5]);
  if( nCell>0 ){
    temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
    memcpy(temp, data, usableSize);
    src = temp;
    for(i=0; i<nCell; i++){
      u8 *pAddr;     /* The i-th cell pointer */
      pAddr = &data[cellOffset + i*2];
      pc = get2byte(pAddr);
      testcase( pc==iCellFirst );
      testcase( pc==iCellLast );

** The first byte of the new free block is pPage->aData[iStart]
** and the size of the block is iSize bytes.
**
** Adjacent freeblocks are coalesced.
**
** Even though the freeblock list was checked by btreeComputeFreeSpace(),
** that routine will not detect overlap between cells or freeblocks.  Nor
** does it detect cells or freeblocks that encroach into the reserved bytes
** at the end of the page.  So do additional corruption checks inside this
** routine and return SQLITE_CORRUPT if any problems are found.
*/
static int freeSpace(MemPage *pPage, u16 iStart, u16 iSize){
  u16 iPtr;                             /* Address of ptr to next freeblock */
  u16 iFreeBlk;                         /* Address of the next freeblock */
  u8 hdr;                               /* Page header size.  0 or 100 */

SQLITE_PRIVATE Pgno sqlite3BtreeLastPage(Btree *p){
  assert( sqlite3BtreeHoldsMutex(p) );
  return btreePagecount(p->pBt);
}

/*
** Get a page from the pager and initialize it.










*/
static int getAndInitPage(
  BtShared *pBt,                  /* The database file */
  Pgno pgno,                      /* Number of the page to get */
  MemPage **ppPage,               /* Write the page pointer here */

  int bReadOnly                   /* True for a read-only page */
){
  int rc;
  DbPage *pDbPage;
  MemPage *pPage;
  assert( sqlite3_mutex_held(pBt->mutex) );




  if( pgno>btreePagecount(pBt) ){
    *ppPage = 0;
    return SQLITE_CORRUPT_BKPT;

  }
  rc = sqlite3PagerGet(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadOnly);
  if( rc ){
    *ppPage = 0;
    return rc;
  }
  pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
  if( pPage->isInit==0 ){
    btreePageFromDbPage(pDbPage, pgno, pBt);
    rc = btreeInitPage(pPage);
    if( rc!=SQLITE_OK ){
      releasePage(pPage);
      *ppPage = 0;
      return rc;
    }
  }
  assert( pPage->pgno==pgno || CORRUPT_DB );
  assert( pPage->aData==sqlite3PagerGetData(pDbPage) );
  *ppPage = pPage;






  return SQLITE_OK;











}

/*
** Release a MemPage.  This should be called once for each prior
** call to btreeGetPage.
**
** Page1 is a special case and must be released using releasePageOne().

    pPage->isInit = 0;
    if( sqlite3PagerPageRefcount(pData)>1 ){
      /* pPage might not be a btree page;  it might be an overflow page
      ** or ptrmap page or a free page.  In those cases, the following
      ** call to btreeInitPage() will likely return SQLITE_CORRUPT.
      ** But no harm is done by this.  And it is very important that
      ** btreeInitPage() be called on every btree page so we make
      ** the call for every page that comes in for re-initializing. */
      btreeInitPage(pPage);
    }
  }
}

/*
** Invoke the busy handler for a btree.

    ** when compiling on a different architecture.
    */
    assert( sizeof(i64)==8 );
    assert( sizeof(u64)==8 );
    assert( sizeof(u32)==4 );
    assert( sizeof(u16)==2 );
    assert( sizeof(Pgno)==4 );

    /* Suppress false-positive compiler warning from PVS-Studio */
    memset(&zDbHeader[16], 0, 8);

    pBt = sqlite3MallocZero( sizeof(*pBt) );
    if( pBt==0 ){
      rc = SQLITE_NOMEM_BKPT;
      goto btree_open_out;
    }
    rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,

  /* One of the uses of pBt->pTmpSpace is to format cells before
  ** inserting them into a leaf page (function fillInCell()). If
  ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
  ** by the various routines that manipulate binary cells. Which
  ** can mean that fillInCell() only initializes the first 2 or 3
  ** bytes of pTmpSpace, but that the first 4 bytes are copied from
  ** it into a database page. This is not actually a problem, but it
  ** does cause a valgrind error when the 1 or 2 bytes of uninitialized
  ** data is passed to system call write(). So to avoid this error,
  ** zero the first 4 bytes of temp space here.
  **
  ** Also:  Provide four bytes of initialized space before the
  ** beginning of pTmpSpace as an area available to prepend the
  ** left-child pointer to the beginning of a cell.
  */

  assert( sqlite3_mutex_held(p->pBt->mutex) );
  n = p->pBt->pageSize - p->pBt->usableSize;
  return n;
}

/*
** Return the number of bytes of space at the end of every page that
** are intentionally left unused.  This is the "reserved" space that is
** sometimes used by extensions.
**
** The value returned is the larger of the current reserve size and
** the latest reserve size requested by SQLITE_FILECTRL_RESERVE_BYTES.
** The amount of reserve can only grow - never shrink.
*/
SQLITE_PRIVATE int sqlite3BtreeGetRequestedReserve(Btree *p){

    ** between 512 and 65536 inclusive. */
    if( ((pageSize-1)&pageSize)!=0
     || pageSize>SQLITE_MAX_PAGE_SIZE
     || pageSize<=256
    ){
      goto page1_init_failed;
    }

    assert( (pageSize & 7)==0 );
    /* EVIDENCE-OF: R-59310-51205 The "reserved space" size in the 1-byte
    ** integer at offset 20 is the number of bytes of space at the end of
    ** each page to reserve for extensions.
    **
    ** EVIDENCE-OF: R-37497-42412 The size of the reserved region is
    ** determined by the one-byte unsigned integer found at an offset of 20
    ** into the database file header. */
    usableSize = pageSize - page1[20];
    if( (u32)pageSize!=pBt->pageSize ){
      /* After reading the first page of the database assuming a page size
      ** of BtShared.pageSize, we have discovered that the page-size is
      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
      ** zero and return SQLITE_OK. The caller will call this function
      ** again with the correct page-size.
      */
      releasePageOne(pPage1);
      pBt->usableSize = usableSize;
      pBt->pageSize = pageSize;
      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
      freeTempSpace(pBt);
      rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
                                   pageSize-usableSize);
      return rc;
    }
    if( nPage>nPageFile ){
      if( sqlite3WritableSchema(pBt->db)==0 ){
        rc = SQLITE_CORRUPT_BKPT;
        goto page1_init_failed;
      }else{
        nPage = nPageFile;
      }
    }
    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
    ** be less than 480. In other words, if the page size is 512, then the
    ** reserved space size cannot exceed 32. */
    if( usableSize<480 ){
      goto page1_init_failed;
    }
    pBt->btsFlags |= BTS_PAGESIZE_FIXED;
    pBt->pageSize = pageSize;
    pBt->usableSize = usableSize;
#ifndef SQLITE_OMIT_AUTOVACUUM
    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
    pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
#endif
  }

** a reserved lock.  B tries to promote to exclusive but is blocked because
** of A's read lock.  A tries to promote to reserved but is blocked by B.
** One or the other of the two processes must give way or there can be
** no progress.  By returning SQLITE_BUSY and not invoking the busy callback
** when A already has a read lock, we encourage A to give up and let B
** proceed.
*/
static SQLITE_NOINLINE int btreeBeginTrans(
  Btree *p,                 /* The btree in which to start the transaction */
  int wrflag,               /* True to start a write transaction */
  int *pSchemaVersion       /* Put schema version number here, if not NULL */
){
  BtShared *pBt = p->pBt;
  Pager *pPager = pBt->pPager;
  int rc = SQLITE_OK;

  sqlite3BtreeEnter(p);
  btreeIntegrity(p);

      rc = sqlite3PagerOpenSavepoint(pPager, p->db->nSavepoint);
    }
  }

  btreeIntegrity(p);
  sqlite3BtreeLeave(p);
  return rc;
}
SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag, int *pSchemaVersion){
  BtShared *pBt;
  if( p->sharable
   || p->inTrans==TRANS_NONE
   || (p->inTrans==TRANS_READ && wrflag!=0)
  ){
    return btreeBeginTrans(p,wrflag,pSchemaVersion);
  }
  pBt = p->pBt;
  if( pSchemaVersion ){
    *pSchemaVersion = get4byte(&pBt->pPage1->aData[40]);
  }
  if( wrflag ){
    /* This call makes sure that the pager has the correct number of
    ** open savepoints. If the second parameter is greater than 0 and
    ** the sub-journal is not already open, then it will be opened here.
    */
    return sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
  }else{
    return SQLITE_OK;
  }
}

#ifndef SQLITE_OMIT_AUTOVACUUM

/*
** Set the pointer-map entries for all children of page pPage. Also, if
** pPage contains cells that point to overflow pages, set the pointer

  pCur->curFlags |= BTCF_Pinned;
}
SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor *pCur){
  assert( (pCur->curFlags & BTCF_Pinned)!=0 );
  pCur->curFlags &= ~BTCF_Pinned;
}


/*
** Return the offset into the database file for the start of the
** payload to which the cursor is pointing.
*/
SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  getCellInfo(pCur);
  return (i64)pCur->pBt->pageSize*((i64)pCur->pPage->pgno - 1) +
         (i64)(pCur->info.pPayload - pCur->pPage->aData);
}


/*
** Return the number of bytes of payload for the entry that pCur is
** currently pointing to.  For table btrees, this will be the amount
** of data.  For index btrees, this will be the size of the key.
**
** The caller must guarantee that the cursor is pointing to a non-NULL

** Return an upper bound on the size of any record for the table
** that the cursor is pointing into.
**
** This is an optimization.  Everything will still work if this
** routine always returns 2147483647 (which is the largest record
** that SQLite can handle) or more.  But returning a smaller value might
** prevent large memory allocations when trying to interpret a
** corrupt database.
**
** The current implementation merely returns the size of the underlying
** database file.
*/
SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );

**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
  int rc;
  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
  assert( pCur->iPage>=0 );
  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
    return SQLITE_CORRUPT_BKPT;
  }
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  pCur->aiIdx[pCur->iPage] = pCur->ix;
  pCur->apPage[pCur->iPage] = pCur->pPage;
  pCur->ix = 0;
  pCur->iPage++;
  rc = getAndInitPage(pCur->pBt, newPgno, &pCur->pPage, pCur->curPagerFlags);
  assert( pCur->pPage!=0 || rc!=SQLITE_OK );
  if( rc==SQLITE_OK
   && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
  ){
    releasePage(pCur->pPage);
    rc = SQLITE_CORRUPT_PGNO(newPgno);
  }
  if( rc ){
    pCur->pPage = pCur->apPage[--pCur->iPage];
  }
  return rc;
}

#ifdef SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of

      if( pCur->eState==CURSOR_FAULT ){
        assert( pCur->skipNext!=SQLITE_OK );
        return pCur->skipNext;
      }
      sqlite3BtreeClearCursor(pCur);
    }
    rc = getAndInitPage(pCur->pBt, pCur->pgnoRoot, &pCur->pPage,
                        pCur->curPagerFlags);
    if( rc!=SQLITE_OK ){
      pCur->eState = CURSOR_INVALID;
      return rc;
    }
    pCur->iPage = 0;
    pCur->curIntKey = pCur->pPage->intKey;
  }

  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  rc = moveToRoot(pCur);
  if( rc==SQLITE_OK ){
    assert( pCur->pPage->nCell>0 );
    *pRes = 0;
    rc = moveToLeftmost(pCur);
  }else if( rc==SQLITE_EMPTY ){
    assert( pCur->pgnoRoot==0 || (pCur->pPage!=0 && pCur->pPage->nCell==0) );
    *pRes = 1;
    rc = SQLITE_OK;
  }
  return rc;
}

/* Move the cursor to the last entry in the table.  Return SQLITE_OK

      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
        *pRes = -1;
        return SQLITE_OK;
      }
      /* If the requested key is one more than the previous key, then
      ** try to get there using sqlite3BtreeNext() rather than a full
      ** binary search.  This is an optimization only.  The correct answer
      ** is still obtained without this case, only a little more slowly. */
      if( pCur->info.nKey+1==intKey ){
        *pRes = 0;
        rc = sqlite3BtreeNext(pCur, 0);
        if( rc==SQLITE_OK ){
          getCellInfo(pCur);
          if( pCur->info.nKey==intKey ){
            return SQLITE_OK;

      goto moveto_index_finish;
    }
    if( lwr>=pPage->nCell ){
      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    }else{
      chldPg = get4byte(findCell(pPage, lwr));
    }

    /* This block is similar to an in-lined version of:
    **
    **    pCur->ix = (u16)lwr;
    **    rc = moveToChild(pCur, chldPg);
    **    if( rc ) break;
    */
    pCur->info.nSize = 0;
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
    if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
      return SQLITE_CORRUPT_BKPT;
    }
    pCur->aiIdx[pCur->iPage] = (u16)lwr;
    pCur->apPage[pCur->iPage] = pCur->pPage;
    pCur->ix = 0;
    pCur->iPage++;
    rc = getAndInitPage(pCur->pBt, chldPg, &pCur->pPage, pCur->curPagerFlags);
    if( rc==SQLITE_OK
     && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
    ){
      releasePage(pCur->pPage);
      rc = SQLITE_CORRUPT_PGNO(chldPg);
    }
    if( rc ){
      pCur->pPage = pCur->apPage[--pCur->iPage];
      break;
    }
    /*
    ***** End of in-lined moveToChild() call */
 }
moveto_index_finish:
  pCur->info.nSize = 0;
  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
  return rc;
}

    ovflPgno = iNext;
  }
  return SQLITE_OK;
}

/* Call xParseCell to compute the size of a cell.  If the cell contains
** overflow, then invoke cellClearOverflow to clear out that overflow.
** Store the result code (SQLITE_OK or some error code) in rc.
**
** Implemented as macro to force inlining for performance.
*/
#define BTREE_CLEAR_CELL(rc, pPage, pCell, sInfo)   \
  pPage->xParseCell(pPage, pCell, &sInfo);          \
  if( sInfo.nLocal!=sInfo.nPayload ){               \
    rc = clearCellOverflow(pPage, pCell, &sInfo);   \

  u8 *pSrcEnd;                    /* Current pCArray->apEnd[k] value */

  assert( i<iEnd );
  j = get2byte(&aData[hdr+5]);
  if( NEVER(j>(u32)usableSize) ){ j = 0; }
  memcpy(&pTmp[j], &aData[j], usableSize - j);

  for(k=0; ALWAYS(k<NB*2) && pCArray->ixNx[k]<=i; k++){}
  pSrcEnd = pCArray->apEnd[k];

  pData = pEnd;
  while( 1/*exit by break*/ ){
    u8 *pCell = pCArray->apCell[i];
    u16 sz = pCArray->szCell[i];
    assert( sz>0 );

** content area on page pPg. If the size of the content area is extended,
** *ppData is updated to point to the new start of the content area
** before returning.
**
** Finally, argument pBegin points to the byte immediately following the
** end of the space required by this page for the cell-pointer area (for
** all cells - not just those inserted by the current call). If the content
** area must be extended to before this point in order to accommodate all
** cells in apCell[], then the cells do not fit and non-zero is returned.
*/
static int pageInsertArray(
  MemPage *pPg,                   /* Page to add cells to */
  u8 *pBegin,                     /* End of cell-pointer array */
  u8 **ppData,                    /* IN/OUT: Page content-area pointer */
  u8 *pCellptr,                   /* Pointer to cell-pointer area */
  int iFirst,                     /* Index of first cell to add */
  int nCell,                      /* Number of cells to add to pPg */
  CellArray *pCArray              /* Array of cells */
){
  int i = iFirst;                 /* Loop counter - cell index to insert */
  u8 *aData = pPg->aData;         /* Complete page */
  u8 *pData = *ppData;            /* Content area.  A subset of aData[] */
  int iEnd = iFirst + nCell;      /* End of loop. One past last cell to ins */
  int k;                          /* Current slot in pCArray->apEnd[] */
  u8 *pEnd;                       /* Maximum extent of cell data */
  assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
  if( iEnd<=iFirst ) return 0;
  for(k=0; ALWAYS(k<NB*2) && pCArray->ixNx[k]<=i ; k++){}
  pEnd = pCArray->apEnd[k];
  while( 1 /*Exit by break*/ ){
    int sz, rc;
    u8 *pSlot;
    assert( pCArray->szCell[i]!=0 );
    sz = pCArray->szCell[i];
    if( (aData[1]==0 && aData[2]==0) || (pSlot = pageFindSlot(pPg,sz,&rc))==0 ){

  }
  if( iNewEnd < iOldEnd ){
    int nTail = pageFreeArray(pPg, iNewEnd, iOldEnd - iNewEnd, pCArray);
    assert( nCell>=nTail );
    nCell -= nTail;
  }

  pData = &aData[get2byte(&aData[hdr+5])];
  if( pData<pBegin ) goto editpage_fail;
  if( NEVER(pData>pPg->aDataEnd) ) goto editpage_fail;

  /* Add cells to the start of the page */
  if( iNew<iOld ){
    int nAdd = MIN(nNew,iOld-iNew);
    assert( (iOld-iNew)<nNew || nCell==0 || CORRUPT_DB );

    }
    pNew->nFree = pBt->usableSize - pNew->cellOffset - 2 - szCell;

    /* If this is an auto-vacuum database, update the pointer map
    ** with entries for the new page, and any pointer from the
    ** cell on the page to an overflow page. If either of these
    ** operations fails, the return code is set, but the contents
    ** of the parent page are still manipulated by the code below.
    ** That is Ok, at this point the parent page is guaranteed to
    ** be marked as dirty. Returning an error code will cause a
    ** rollback, undoing any changes made to the parent page.
    */
    if( ISAUTOVACUUM(pBt) ){
      ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno, &rc);
      if( szCell>pNew->minLocal ){

    pRight = &pParent->aData[pParent->hdrOffset+8];
  }else{
    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
  }
  pgno = get4byte(pRight);
  while( 1 ){
    if( rc==SQLITE_OK ){
      rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
    }
    if( rc ){
      memset(apOld, 0, (i+1)*sizeof(MemPage*));
      goto balance_cleanup;
    }
    if( apOld[i]->nFree<0 ){
      rc = btreeComputeFreeSpace(apOld[i]);

    szNew[i-1] = szLeft;
    if( cntNew[i-1] <= (i>1 ? cntNew[i-2] : 0) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto balance_cleanup;
    }
  }

  /* Sanity check:  For a non-corrupt database file one of the following
  ** must be true:
  **    (1) We found one or more cells (cntNew[0])>0), or
  **    (2) pPage is a virtual root page.  A virtual root page is when
  **        the real root page is page 1 and we are the only child of
  **        that page.
  */
  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) || CORRUPT_DB);

        assert(leafCorrection==4);
        sz = pParent->xCellSize(pParent, pCell);
      }
    }
    iOvflSpace += sz;
    assert( sz<=pBt->maxLocal+23 );
    assert( iOvflSpace <= (int)pBt->pageSize );
    for(k=0; ALWAYS(k<NB*2) && b.ixNx[k]<=j; k++){}
    pSrcEnd = b.apEnd[k];
    if( SQLITE_OVERFLOW(pSrcEnd, pCell, pCell+sz) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto balance_cleanup;
    }
    rc = insertCell(pParent, nxDiv+i, pCell, sz, pTemp, pNew->pgno);
    if( rc!=SQLITE_OK ) goto balance_cleanup;
    assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  }

  ** step.  On the upward pass, both conditions are always true, so the
  ** upwards pass simply processes pages that were missed on the downward
  ** pass.
  */
  for(i=1-nNew; i<nNew; i++){
    int iPg = i<0 ? -i : i;
    assert( iPg>=0 && iPg<nNew );
    assert( iPg>=1 || i>=0 );
    assert( iPg<ArraySize(cntOld) );
    if( abDone[iPg] ) continue;         /* Skip pages already processed */
    if( i>=0                            /* On the upwards pass, or... */
     || cntOld[iPg-1]>=cntNew[iPg-1]    /* Condition (1) is true */
    ){
      int iNew;
      int iOld;
      int nNewCell;

  u8 *pDest,                /* Pointer to the place to start writing */
  const BtreePayload *pX,   /* Source of data to write */
  int iOffset,              /* Offset of first byte to write */
  int iAmt                  /* Number of bytes to be written */
){
  int nData = pX->nData - iOffset;
  if( nData<=0 ){
    /* Overwriting with zeros */
    int i;
    for(i=0; i<iAmt && pDest[i]==0; i++){}
    if( i<iAmt ){
      int rc = sqlite3PagerWrite(pPage->pDbPage);
      if( rc ) return rc;
      memset(pDest + i, 0, iAmt - i);
    }

/*
** Overwrite the cell that cursor pCur is pointing to with fresh content
** contained in pX.  In this variant, pCur is pointing to an overflow
** cell.
*/
static SQLITE_NOINLINE int btreeOverwriteOverflowCell(
  BtCursor *pCur,                     /* Cursor pointing to cell to overwrite */
  const BtreePayload *pX              /* Content to write into the cell */
){
  int iOffset;                        /* Next byte of pX->pData to write */
  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
  int rc;                             /* Return code */
  MemPage *pPage = pCur->pPage;       /* Page being written */
  BtShared *pBt;                      /* Btree */

**     BTREE_ZERODATA                  Used for SQL indices
*/
static int btreeCreateTable(Btree *p, Pgno *piTable, int createTabFlags){
  BtShared *pBt = p->pBt;
  MemPage *pRoot;
  Pgno pgnoRoot;
  int rc;
  int ptfFlags;          /* Page-type flags for the root page of new table */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );

#ifdef SQLITE_OMIT_AUTOVACUUM
  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);

  int hdr;
  CellInfo info;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = getAndInitPage(pBt, pgno, &pPage, 0);
  if( rc ) return rc;
  if( (pBt->openFlags & BTREE_SINGLE)==0
   && sqlite3PagerPageRefcount(pPage->pDbPage) != (1 + (pgno==1))
  ){
    rc = SQLITE_CORRUPT_BKPT;
    goto cleardatabasepage_out;
  }

  checkProgress(pCheck);
  if( pCheck->mxErr==0 ) goto end_of_check;
  pBt = pCheck->pBt;
  usableSize = pBt->usableSize;
  if( iPage==0 ) return 0;
  if( checkRef(pCheck, iPage) ) return 0;
  pCheck->zPfx = "Tree %u page %u: ";
  pCheck->v1 = iPage;
  if( (rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0 ){
    checkAppendMsg(pCheck,
       "unable to get the page. error code=%d", rc);
    goto end_of_check;
  }

  /* Clear MemPage.isInit to make sure the corruption detection code in

    i64 notUsed;
    if( aRoot[i]==0 ) continue;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum && aRoot[i]>1 && !bPartial ){
      checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0);
    }
#endif
    sCheck.v0 = aRoot[i];
    checkTreePage(&sCheck, aRoot[i], &notUsed, LARGEST_INT64);
  }
  pBt->db->flags = savedDbFlags;

  /* Make sure every page in the file is referenced
  */
  if( !bPartial ){

    return sqlite3VdbeMemGrow(pMem, szNew, 0);
  }
  assert( (pMem->flags & MEM_Dyn)==0 );
  pMem->z = pMem->zMalloc;
  pMem->flags &= (MEM_Null|MEM_Int|MEM_Real|MEM_IntReal);
  return SQLITE_OK;
}

/*
** If pMem is already a string, detect if it is a zero-terminated
** string, or make it into one if possible, and mark it as such.
**
** This is an optimization.  Correct operation continues even if
** this routine is a no-op.
*/
SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
  if( (pMem->flags & (MEM_Str|MEM_Term|MEM_Ephem|MEM_Static))!=MEM_Str ){
    /* pMem must be a string, and it cannot be an ephemeral or static string */
    return;
  }
  if( pMem->enc!=SQLITE_UTF8 ) return;
  if( NEVER(pMem->z==0) ) return;
  if( pMem->flags & MEM_Dyn ){
    if( pMem->xDel==sqlite3_free
     && sqlite3_msize(pMem->z) >= (u64)(pMem->n+1)
    ){
      pMem->z[pMem->n] = 0;
      pMem->flags |= MEM_Term;
      return;
    }
    if( pMem->xDel==(void(*)(void*))sqlite3RCStrUnref ){
      /* Blindly assume that all RCStr objects are zero-terminated */
      pMem->flags |= MEM_Term;
      return;
    }
  }else if( pMem->szMalloc >= pMem->n+1 ){
    pMem->z[pMem->n] = 0;
    pMem->flags |= MEM_Term;
    return;
  }
}

/*
** It is already known that pMem contains an unterminated string.
** Add the zero terminator.
**
** Three bytes of zero are added.  In this way, there is guaranteed
** to be a double-zero byte at an even byte boundary in order to

** know in advance that the Mem is not MEM_Dyn or MEM_Agg.
*/
SQLITE_PRIVATE void sqlite3VdbeMemReleaseMalloc(Mem *p){
  assert( !VdbeMemDynamic(p) );
  if( p->szMalloc ) vdbeMemClear(p);
}































/*
** Return some kind of integer value which is the best we can do
** at representing the value that *pMem describes as an integer.
** If pMem is an integer, then the value is exact.  If pMem is
** a floating-point then the value returned is the integer part.
** If pMem is a string or blob, then we make an attempt to convert
** it into an integer and return that.  If pMem represents an

  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
  flags = pMem->flags;
  if( flags & (MEM_Int|MEM_IntReal) ){
    testcase( flags & MEM_IntReal );
    return pMem->u.i;
  }else if( flags & MEM_Real ){
    return sqlite3RealToI64(pMem->u.r);
  }else if( (flags & (MEM_Str|MEM_Blob))!=0 && pMem->z!=0 ){
    return memIntValue(pMem);
  }else{
    return 0;
  }
}

  assert( !sqlite3VdbeMemIsRowSet(pMem) );
  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  assert( EIGHT_BYTE_ALIGNMENT(pMem) );

  if( pMem->flags & MEM_IntReal ){
    MemSetTypeFlag(pMem, MEM_Int);
  }else{
    i64 ix = sqlite3RealToI64(pMem->u.r);

    /* Only mark the value as an integer if
    **
    **    (1) the round-trip conversion real->int->real is a no-op, and
    **    (2) The integer is neither the largest nor the smallest
    **        possible integer (ticket #3922)
    **

}

/* Convert a floating point value to its closest integer.  Do so in
** a way that avoids 'outside the range of representable values' warnings
** from UBSAN.
*/
SQLITE_PRIVATE i64 sqlite3RealToI64(double r){
  if( r<-9223372036854774784.0 ) return SMALLEST_INT64;
  if( r>+9223372036854774784.0 ) return LARGEST_INT64;
  return (i64)r;
}

/*
** Convert pMem so that it has type MEM_Real or MEM_Int.
** Invalidate any prior representations.
**

      break;
    }
    case SQLITE_AFF_REAL: {
      sqlite3VdbeMemRealify(pMem);
      break;
    }
    default: {
      int rc;
      assert( aff==SQLITE_AFF_TEXT );
      assert( MEM_Str==(MEM_Blob>>3) );
      pMem->flags |= (pMem->flags&MEM_Blob)>>3;
      sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
      assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
      pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
      if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
      rc = sqlite3VdbeChangeEncoding(pMem, encoding);
      if( rc ) return rc;
      sqlite3VdbeMemZeroTerminateIfAble(pMem);
    }
  }
  return SQLITE_OK;
}

/*
** Initialize bulk memory to be a consistent Mem object.

    return pVal->z;
  }
  if( pVal->flags&MEM_Null ){
    return 0;
  }
  return valueToText(pVal, enc);
}

/* Return true if sqlit3_value object pVal is a string or blob value
** that uses the destructor specified in the second argument.
**
** TODO:  Maybe someday promote this interface into a published API so
** that third-party extensions can get access to it?
*/
SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value *pVal, void(*xFree)(void*)){
  if( ALWAYS(pVal!=0)
   && ALWAYS((pVal->flags & (MEM_Str|MEM_Blob))!=0)
   && (pVal->flags & MEM_Dyn)!=0
   && pVal->xDel==xFree
  ){
    return 1;
  }else{
    return 0;
  }
}

/*
** Create a new sqlite3_value object.
*/
SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *db){
  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
  if( p ){

        }
      }
      if( pRec==0 ) return 0;
      p->ppRec[0] = pRec;
    }

    pRec->nField = p->iVal+1;
    sqlite3VdbeMemSetNull(&pRec->aMem[p->iVal]);
    return &pRec->aMem[p->iVal];
  }
#else
  UNUSED_PARAMETER(p);
#endif /* defined(SQLITE_ENABLE_STAT4) */
  return sqlite3ValueNew(db);
}

static void test_addop_breakpoint(int pc, Op *pOp){
  static int n = 0;
  (void)pc;
  (void)pOp;
  n++;
}
#endif

/*
** Slow paths for sqlite3VdbeAddOp3() and sqlite3VdbeAddOp4Int() for the
** unusual case when we need to increase the size of the Vdbe.aOp[] array
** before adding the new opcode.
*/
static SQLITE_NOINLINE int growOp3(Vdbe *p, int op, int p1, int p2, int p3){
  assert( p->nOpAlloc<=p->nOp );
  if( growOpArray(p, 1) ) return 1;
  assert( p->nOpAlloc>p->nOp );
  return sqlite3VdbeAddOp3(p, op, p1, p2, p3);
}
static SQLITE_NOINLINE int addOp4IntSlow(
  Vdbe *p,            /* Add the opcode to this VM */
  int op,             /* The new opcode */
  int p1,             /* The P1 operand */
  int p2,             /* The P2 operand */
  int p3,             /* The P3 operand */
  int p4              /* The P4 operand as an integer */
){
  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
  if( p->db->mallocFailed==0 ){
    VdbeOp *pOp = &p->aOp[addr];
    pOp->p4type = P4_INT32;
    pOp->p4.i = p4;
  }
  return addr;
}


/*
** Add a new instruction to the list of instructions current in the
** VDBE.  Return the address of the new instruction.
**
** Parameters:
**
**    p               Pointer to the VDBE
**
**    op              The opcode for this instruction
**
**    p1, p2, p3, p4  Operands




*/
SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe *p, int op){
  return sqlite3VdbeAddOp3(p, op, 0, 0, 0);
}
SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){

  return sqlite3VdbeAddOp3(p, op, p1, 0, 0);

}
SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){
  return sqlite3VdbeAddOp3(p, op, p1, p2, 0);
}
SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
  int i;
  VdbeOp *pOp;

  i = p->nOp;
  assert( p->eVdbeState==VDBE_INIT_STATE );

  pOp->opcode = (u8)op;
  pOp->p5 = 0;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = p3;
  pOp->p4.p = 0;
  pOp->p4type = P4_NOTUSED;

  /* Replicate this logic in sqlite3VdbeAddOp4Int()
  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
  pOp->zComment = 0;
#endif
#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
  pOp->nExec = 0;
  pOp->nCycle = 0;
#endif
#ifdef SQLITE_DEBUG
  if( p->db->flags & SQLITE_VdbeAddopTrace ){
    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
    test_addop_breakpoint(i, &p->aOp[i]);
  }
#endif
#ifdef SQLITE_VDBE_COVERAGE
  pOp->iSrcLine = 0;
#endif
  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ** Replicate in sqlite3VdbeAddOp4Int() */

  return i;
}
SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(
  Vdbe *p,            /* Add the opcode to this VM */
  int op,             /* The new opcode */
  int p1,             /* The P1 operand */
  int p2,             /* The P2 operand */
  int p3,             /* The P3 operand */
  int p4              /* The P4 operand as an integer */
){
  int i;
  VdbeOp *pOp;

  i = p->nOp;
  if( p->nOpAlloc<=i ){
    return addOp4IntSlow(p, op, p1, p2, p3, p4);
  }
  p->nOp++;
  pOp = &p->aOp[i];
  assert( pOp!=0 );
  pOp->opcode = (u8)op;
  pOp->p5 = 0;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = p3;
  pOp->p4.i = p4;
  pOp->p4type = P4_INT32;

  /* Replicate this logic in sqlite3VdbeAddOp3()
  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
  pOp->zComment = 0;
#endif
#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
  pOp->nExec = 0;
  pOp->nCycle = 0;
#endif
#ifdef SQLITE_DEBUG
  if( p->db->flags & SQLITE_VdbeAddopTrace ){
    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
    test_addop_breakpoint(i, &p->aOp[i]);
  }
#endif
#ifdef SQLITE_VDBE_COVERAGE
  pOp->iSrcLine = 0;
#endif
  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


  ** Replicate in sqlite3VdbeAddOp3() */


  return i;
}




/* Generate code for an unconditional jump to instruction iDest
*/
SQLITE_PRIVATE int sqlite3VdbeGoto(Vdbe *p, int iDest){
  return sqlite3VdbeAddOp3(p, OP_Goto, 0, iDest, 0);
}

    iThis = v->nOp;
    addr = sqlite3VdbeAddOp4(v, OP_Explain, iThis, pParse->addrExplain, 0,
                      zMsg, P4_DYNAMIC);
    sqlite3ExplainBreakpoint(bPush?"PUSH":"", sqlite3VdbeGetLastOp(v)->p4.z);
    if( bPush){
      pParse->addrExplain = iThis;
    }
    sqlite3VdbeScanStatus(v, iThis, -1, -1, 0, 0);
  }
  return addr;
}

/*
** Pop the EXPLAIN QUERY PLAN stack one level.
*/

  int j;
  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
  sqlite3VdbeChangeP5(p, p5);
  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
  sqlite3MayAbort(p->pParse);
}





















/* Insert the end of a co-routine
*/
SQLITE_PRIVATE void sqlite3VdbeEndCoroutine(Vdbe *v, int regYield){
  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);

  /* Clear the temporary register cache, thereby ensuring that each
  ** co-routine has its own independent set of registers, because co-routines

  int *aLabel = pParse->aLabel;

  assert( pParse->db->mallocFailed==0 ); /* tag-20230419-1 */
  p->readOnly = 1;
  p->bIsReader = 0;
  pOp = &p->aOp[p->nOp-1];
  assert( p->aOp[0].opcode==OP_Init );
  while( 1 /* Loop terminates when it reaches the OP_Init opcode */ ){
    /* Only JUMP opcodes and the short list of special opcodes in the switch
    ** below need to be considered.  The mkopcodeh.tcl generator script groups
    ** all these opcodes together near the front of the opcode list.  Skip
    ** any opcode that does not need processing by virtual of the fact that
    ** it is larger than SQLITE_MX_JUMP_OPCODE, as a performance optimization.
    */
    if( pOp->opcode<=SQLITE_MX_JUMP_OPCODE ){

    int ii;
    for(ii=p->nScan-1; ii>=0; ii--){
      pScan = &p->aScan[ii];
      if( pScan->addrExplain==addrExplain ) break;
      pScan = 0;
    }
    if( pScan ){
      if( addrLoop>0 ) pScan->addrLoop = addrLoop;
      if( addrVisit>0 ) pScan->addrVisit = addrVisit;
    }
  }
}
#endif /* defined(SQLITE_ENABLE_STMT_SCANSTATUS) */


/*

    sqlite3VdbeChangeP2(p, addr, p->nOp);
  }
}


/*
** If the input FuncDef structure is ephemeral, then free it.  If
** the FuncDef is not ephemeral, then do nothing.
*/
static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
  assert( db!=0 );
  if( (pDef->funcFlags & SQLITE_FUNC_EPHEM)!=0 ){
    sqlite3DbNNFreeNN(db, pDef);
  }
}

  }
  if( N>0 ){
    sqlite3VdbeAddOp3(pParse->pVdbe, OP_ReleaseReg, iFirst, N, *(int*)&mask);
    if( bUndefine ) sqlite3VdbeChangeP5(pParse->pVdbe, 1);
  }
}
#endif /* SQLITE_DEBUG */


/*
** Change the value of the P4 operand for a specific instruction.
** This routine is useful when a large program is loaded from a
** static array using sqlite3VdbeAddOpList but we want to make a
** few minor changes to the program.
**

    }else{
      char *zP4 = sqlite3VdbeDisplayP4(db, pOp);
      if( p->explain==2 ){
        sqlite3VdbeMemSetInt64(pMem, pOp->p1);
        sqlite3VdbeMemSetInt64(pMem+1, pOp->p2);
        sqlite3VdbeMemSetInt64(pMem+2, pOp->p3);
        sqlite3VdbeMemSetStr(pMem+3, zP4, -1, SQLITE_UTF8, sqlite3_free);
        assert( p->nResColumn==4 );
      }else{
        sqlite3VdbeMemSetInt64(pMem+0, i);
        sqlite3VdbeMemSetStr(pMem+1, (char*)sqlite3OpcodeName(pOp->opcode),
                             -1, SQLITE_UTF8, SQLITE_STATIC);
        sqlite3VdbeMemSetInt64(pMem+2, pOp->p1);
        sqlite3VdbeMemSetInt64(pMem+3, pOp->p2);
        sqlite3VdbeMemSetInt64(pMem+4, pOp->p3);
        /* pMem+5 for p4 is done last */
        sqlite3VdbeMemSetInt64(pMem+6, pOp->p5);
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
        {
          char *zCom = sqlite3VdbeDisplayComment(db, pOp, zP4);
          sqlite3VdbeMemSetStr(pMem+7, zCom, -1, SQLITE_UTF8, sqlite3_free);
        }
#else
        sqlite3VdbeMemSetNull(pMem+7);
#endif
        sqlite3VdbeMemSetStr(pMem+5, zP4, -1, SQLITE_UTF8, sqlite3_free);
        assert( p->nResColumn==8 );
      }
      p->pResultRow = pMem;
      if( db->mallocFailed ){
        p->rc = SQLITE_NOMEM;
        rc = SQLITE_ERROR;
      }else{
        p->rc = SQLITE_OK;

  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
  assert( x.nFree>=0 );
  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );

  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain ){





    if( nMem<10 ) nMem = 10;
    p->explain = pParse->explain;



    p->nResColumn = 12 - 4*p->explain;









  }
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
  ** passes.  On the first pass, we try to reuse unused memory at the
  ** end of the opcode array.  If we are unable to satisfy all memory
  ** requirements by reusing the opcode array tail, then the second

/*
** Close a VDBE cursor and release all the resources that cursor
** happens to hold.
*/
SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
  if( pCx ) sqlite3VdbeFreeCursorNN(p,pCx);
}
static SQLITE_NOINLINE void freeCursorWithCache(Vdbe *p, VdbeCursor *pCx){
  VdbeTxtBlbCache *pCache = pCx->pCache;
  assert( pCx->colCache );
  pCx->colCache = 0;
  pCx->pCache = 0;
  if( pCache->pCValue ){
    sqlite3RCStrUnref(pCache->pCValue);
    pCache->pCValue = 0;
  }
  sqlite3DbFree(p->db, pCache);
  sqlite3VdbeFreeCursorNN(p, pCx);
}
SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe *p, VdbeCursor *pCx){
  if( pCx->colCache ){
    freeCursorWithCache(p, pCx);
    return;
  }
  switch( pCx->eCurType ){
    case CURTYPE_SORTER: {
      sqlite3VdbeSorterClose(p->db, pCx);
      break;
    }
    case CURTYPE_BTREE: {
      assert( pCx->uc.pCursor!=0 );

** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
  int n;
  sqlite3 *db = p->db;

  if( p->nResAlloc ){
    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
    sqlite3DbFree(db, p->aColName);
  }
  n = nResColumn*COLNAME_N;
  p->nResColumn = p->nResAlloc = (u16)nResColumn;
  p->aColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
  if( p->aColName==0 ) return;
  initMemArray(p->aColName, n, db, MEM_Null);
}

/*
** Set the name of the idx'th column to be returned by the SQL statement.

  int idx,                         /* Index of column zName applies to */
  int var,                         /* One of the COLNAME_* constants */
  const char *zName,               /* Pointer to buffer containing name */
  void (*xDel)(void*)              /* Memory management strategy for zName */
){
  int rc;
  Mem *pColName;
  assert( idx<p->nResAlloc );
  assert( var<COLNAME_N );
  if( p->db->mallocFailed ){
    assert( !zName || xDel!=SQLITE_DYNAMIC );
    return SQLITE_NOMEM_BKPT;
  }
  assert( p->aColName!=0 );
  pColName = &(p->aColName[idx+var*p->nResAlloc]);
  rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, xDel);
  assert( rc!=0 || !zName || (pColName->flags&MEM_Term)!=0 );
  return rc;
}

/*
** A read or write transaction may or may not be active on database handle

          ** is required. */
          rc = vdbeCommit(db, p);
        }
        if( rc==SQLITE_BUSY && p->readOnly ){
          sqlite3VdbeLeave(p);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          sqlite3SystemError(db, rc);
          p->rc = rc;
          sqlite3RollbackAll(db, SQLITE_OK);
          p->nChange = 0;
        }else{
          db->nDeferredCons = 0;
          db->nDeferredImmCons = 0;
          db->flags &= ~(u64)SQLITE_DeferFKs;

** the database connection and frees the object itself.
*/
static void sqlite3VdbeClearObject(sqlite3 *db, Vdbe *p){
  SubProgram *pSub, *pNext;
  assert( db!=0 );
  assert( p->db==0 || p->db==db );
  if( p->aColName ){
    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
    sqlite3DbNNFreeNN(db, p->aColName);
  }
  for(pSub=p->pProgram; pSub; pSub=pNext){
    pNext = pSub->pNext;
    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
    sqlite3DbFree(db, pSub);
  }

    ** always be greater than or equal to the amount of required key space.
    ** Use that approximation to avoid the more expensive call to
    ** sqlite3VdbeSerialTypeLen() in the common case.
    */
    if( d1+(u64)serial_type1+2>(u64)nKey1
     && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)>(u64)nKey1
    ){
      if( serial_type1>=1
       && serial_type1<=7
       && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)<=(u64)nKey1+8
       && CORRUPT_DB
      ){
        return 1;  /* corrupt record not detected by
                   ** sqlite3VdbeRecordCompareWithSkip().  Return true
                   ** to avoid firing the assert() */
      }
      break;
    }

    /* Extract the values to be compared.
    */
    sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
    d1 += sqlite3VdbeSerialTypeLen(serial_type1);

    /* RHS is real */
    else if( pRhs->flags & MEM_Real ){
      serial_type = aKey1[idx1];
      if( serial_type>=10 ){
        /* Serial types 12 or greater are strings and blobs (greater than
        ** numbers). Types 10 and 11 are currently "reserved for future
        ** use", so it doesn't really matter what the results of comparing
        ** them to numeric values are.  */
        rc = serial_type==10 ? -1 : +1;
      }else if( serial_type==0 ){
        rc = -1;
      }else{
        sqlite3VdbeSerialGet(&aKey1[d1], serial_type, &mem1);
        if( serial_type==7 ){
          if( mem1.u.r<pRhs->u.r ){