Wapp

#!/usr/bin/make
#
# Makefile for wapptclsh on unix.  Usage:
#
#    make clean wapptclsh
#
# You need a static build of TCL9 in the directory that TCLDIR specifies.
# To construct such a build:
#
#    (1)  Download and untar the TCL9 sources
#    (2)  CD into the unix subdirectory
#    (3)  ./configure --disable-shared --prefix=$HOME/tcl90

#    (4)  make install
#

CFLAGS = -Os -static
CC = gcc $(CFLAGS)
OPTS = 
TCLDIR ?= $(HOME)/tcl90
TCLLIB = $(TCLDIR)/lib/libtcl9.0.a -lm -lz -lpthread -ldl
TCLINC = $(TCLDIR)/include
TCLSH = $(TCLDIR)/bin/tclsh9.0

all: wapptclsh

wapptclsh: wapptclsh.c
	$(CC) -I. -I$(TCLINC) -o $@ $(OPTS) wapptclsh.c $(TCLLIB)

wapptclsh.c:	wapptclsh.c.in wapp.tcl wapptclsh.tcl tclsqlite3.c mkccode.tcl
	$(TCLSH) mkccode.tcl wapptclsh.c.in >$@

env:
	@ echo CC = $(CC)
	@ echo OPTS = $(OPTS)
	@ echo TCLDIR = $(TCLDIR)

clean:	
	rm -f wapptclsh wapptclsh.c

** 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
** 6eb2939a6093c0796910645172d80c530555 with changes in files:
**
**    
*/
#ifndef SQLITE_AMALGAMATION
#define SQLITE_CORE 1
#define SQLITE_AMALGAMATION 1
#ifndef SQLITE_PRIVATE

** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
** be larger than the release from which it is derived.  Either Y will
** be held constant and Z will be incremented or else Y will be incremented
** and Z will be reset to zero.
**
** Since [version 3.6.18] ([dateof:3.6.18]),
** SQLite source code has been stored in the
** <a href="http://fossil-scm.org/">Fossil configuration management
** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
** a string which identifies a particular check-in of SQLite
** within its configuration management system.  ^The SQLITE_SOURCE_ID
** string contains the date and time of the check-in (UTC) and a SHA1
** or SHA3-256 hash of the entire source tree.  If the source code has
** 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        "3.50.0"
#define SQLITE_VERSION_NUMBER 3050000
#define SQLITE_SOURCE_ID      "2025-05-06 17:56:32 6eb2939a6093c0796910645172d80c53055559dd57c012f1dc815d89fbf84447"

/*
** 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

** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
** to block for up to M milliseconds before failing when attempting to
** obtain a file lock using the xLock or xShmLock methods of the VFS.
** The parameter is a pointer to a 32-bit signed integer that contains
** the value that M is to be set to. Before returning, the 32-bit signed
** integer is overwritten with the previous value of M.
**
** <li>[[SQLITE_FCNTL_BLOCK_ON_CONNECT]]
** The [SQLITE_FCNTL_BLOCK_ON_CONNECT] opcode is used to configure the
** VFS to block when taking a SHARED lock to connect to a wal mode database.
** This is used to implement the functionality associated with
** SQLITE_SETLK_BLOCK_ON_CONNECT.
**
** <li>[[SQLITE_FCNTL_DATA_VERSION]]
** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
** a database file.  The argument is a pointer to a 32-bit unsigned integer.
** The "data version" for the pager is written into the pointer.  The
** "data version" changes whenever any change occurs to the corresponding
** database file, either through SQL statements on the same database

#define SQLITE_FCNTL_CKPT_DONE              37
#define SQLITE_FCNTL_RESERVE_BYTES          38
#define SQLITE_FCNTL_CKPT_START             39
#define SQLITE_FCNTL_EXTERNAL_READER        40
#define SQLITE_FCNTL_CKSM_FILE              41
#define SQLITE_FCNTL_RESET_CACHE            42
#define SQLITE_FCNTL_NULL_IO                43
#define SQLITE_FCNTL_BLOCK_ON_CONNECT       44

/* deprecated names */
#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO

** was defined  (using [sqlite3_busy_handler()]) prior to calling
** this routine, that other busy handler is cleared.)^
**
** See also:  [PRAGMA busy_timeout]
*/
SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);

/*
** CAPI3REF: Set the Setlk Timeout
** METHOD: sqlite3
**
** This routine is only useful in SQLITE_ENABLE_SETLK_TIMEOUT builds. If
** the VFS supports blocking locks, it sets the timeout in ms used by
** eligible locks taken on wal mode databases by the specified database
** handle. In non-SQLITE_ENABLE_SETLK_TIMEOUT builds, or if the VFS does
** not support blocking locks, this function is a no-op.
**
** Passing 0 to this function disables blocking locks altogether. Passing
** -1 to this function requests that the VFS blocks for a long time -
** indefinitely if possible. The results of passing any other negative value
** are undefined.
**
** Internally, each SQLite database handle store two timeout values - the
** busy-timeout (used for rollback mode databases, or if the VFS does not
** support blocking locks) and the setlk-timeout (used for blocking locks
** on wal-mode databases). The sqlite3_busy_timeout() method sets both
** values, this function sets only the setlk-timeout value. Therefore,
** to configure separate busy-timeout and setlk-timeout values for a single
** database handle, call sqlite3_busy_timeout() followed by this function.
**
** Whenever the number of connections to a wal mode database falls from
** 1 to 0, the last connection takes an exclusive lock on the database,
** then checkpoints and deletes the wal file. While it is doing this, any
** new connection that tries to read from the database fails with an
** SQLITE_BUSY error. Or, if the SQLITE_SETLK_BLOCK_ON_CONNECT flag is
** passed to this API, the new connection blocks until the exclusive lock
** has been released.
*/
SQLITE_API int sqlite3_setlk_timeout(sqlite3*, int ms, int flags);

/*
** CAPI3REF: Flags for sqlite3_setlk_timeout()
*/
#define SQLITE_SETLK_BLOCK_ON_CONNECT 0x01

/*
** CAPI3REF: Convenience Routines For Running Queries
** METHOD: sqlite3
**
** This is a legacy interface that is preserved for backwards compatibility.
** Use of this interface is not recommended.
**

** more threads at the same moment in time.
**
** For all versions of SQLite up to and including 3.6.23.1, a call to
** [sqlite3_reset()] was required after sqlite3_step() returned anything
** other than [SQLITE_ROW] before any subsequent invocation of
** sqlite3_step().  Failure to reset the prepared statement using
** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1]),
** sqlite3_step() began
** calling [sqlite3_reset()] automatically in this circumstance rather
** than returning [SQLITE_MISUSE].  This is not considered a compatibility
** break because any application that ever receives an SQLITE_MISUSE error
** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
** can be used to restore the legacy behavior.
**

** to be invoked whenever a row is updated, inserted or deleted in
** a [rowid table].
** ^Any callback set by a previous call to this function
** for the same database connection is overridden.
**
** ^The second argument is a pointer to the function to invoke when a
** row is updated, inserted or deleted in a rowid table.
** ^The update hook is disabled by invoking sqlite3_update_hook()
** with a NULL pointer as the second parameter.
** ^The first argument to the callback is a copy of the third argument
** to sqlite3_update_hook().
** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
** or [SQLITE_UPDATE], depending on the operation that caused the callback
** to be invoked.
** ^The third and fourth arguments to the callback contain pointers to the
** database and table name containing the affected row.

** When a session object is disabled (see the [sqlite3session_enable()] API),
** it does not accumulate records when rows are inserted, updated or deleted.
** This may appear to have some counter-intuitive effects if a single row
** is written to more than once during a session. For example, if a row
** is inserted while a session object is enabled, then later deleted while
** the same session object is disabled, no INSERT record will appear in the
** changeset, even though the delete took place while the session was disabled.
** Or, if one field of a row is updated while a session is enabled, and
** then another field of the same row is updated while the session is disabled,
** the resulting changeset will contain an UPDATE change that updates both
** fields.
*/
SQLITE_API int sqlite3session_changeset(
  sqlite3_session *pSession,      /* Session object */
  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
  void **ppChangeset              /* OUT: Buffer containing changeset */
);

** </ul>
**
** To clarify, if this function is called and then a changeset constructed
** using [sqlite3session_changeset()], then after applying that changeset to
** database zFrom the contents of the two compatible tables would be
** identical.
**
** Unless the call to this function is a no-op as described above, it is an
** error if database zFrom does not exist or does not contain the required
** compatible table.
**
** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
** may be set to point to a buffer containing an English language error
** message. It is the responsibility of the caller to free this buffer using
** sqlite3_free().
*/

**    * Columns in an index
**    * Columns in a view
**    * Terms in the SET clause of an UPDATE statement
**    * Terms in the result set of a SELECT statement
**    * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
**    * Terms in the VALUES clause of an INSERT statement
**
** The hard upper limit here is 32767.  Most database people will
** tell you that in a well-normalized database, you usually should
** not have more than a dozen or so columns in any table.  And if
** that is the case, there is no point in having more than a few
** dozen values in any of the other situations described above.
**
** An index can only have SQLITE_MAX_COLUMN columns from the user
** point of view, but the underlying b-tree that implements the index
** might have up to twice as many columns in a WITHOUT ROWID table,
** since must also store the primary key at the end.  Hence the
** column count for Index is u16 instead of i16.
*/
#if !defined(SQLITE_MAX_COLUMN)
# define SQLITE_MAX_COLUMN 2000
#elif SQLITE_MAX_COLUMN>32767
# error SQLITE_MAX_COLUMN may not exceed 32767
#endif

/*
** The maximum length of a single SQL statement in bytes.
**
** It used to be the case that setting this value to zero would
** turn the limit off.  That is no longer true.  It is not possible

#endif

/*
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((size_t)((char*)&((STRUCTURE*)0)->FIELD))
#endif

/*
** Work around C99 "flex-array" syntax for pre-C99 compilers, so as
** to avoid complaints from -fsanitize=strict-bounds.
*/
#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
# define FLEXARRAY
#else
# define FLEXARRAY 1
#endif

/*
** Macros to compute minimum and maximum of two numbers.
*/
#ifndef MIN
# define MIN(A,B) ((A)<(B)?(A):(B))

SQLITE_PRIVATE void sqlite3MemSetArrayInt64(sqlite3_value *aMem, int iIdx, i64 val);

SQLITE_PRIVATE int sqlite3NotPureFunc(sqlite3_context*);
#ifdef SQLITE_ENABLE_BYTECODE_VTAB
SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3*);
#endif

/* Use SQLITE_ENABLE_EXPLAIN_COMMENTS to enable generation of extra
** comments on each VDBE opcode.
**
** Use the SQLITE_ENABLE_MODULE_COMMENTS macro to see some extra no-op
** comments in VDBE programs that show key decision points in the code
** generator.
*/
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
SQLITE_PRIVATE   void sqlite3VdbeComment(Vdbe*, const char*, ...);

  Hash aFunc;                   /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int nAnalysisLimit;           /* Number of index rows to ANALYZE */
  int busyTimeout;              /* Busy handler timeout, in msec */
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  int setlkTimeout;             /* Blocking lock timeout, in msec. -1 -> inf. */
  int setlkFlags;               /* Flags passed to setlk_timeout() */
#endif
  int nSavepoint;               /* Number of non-transaction savepoints */
  int nStatement;               /* Number of nested statement-transactions  */
  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
  i64 nDeferredImmCons;         /* Net deferred immediate constraints */
  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
  DbClientData *pDbData;        /* sqlite3_set_clientdata() content */
#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY

  /* EV: R-30323-21917 */
  u8 isDeferred;       /* True if constraint checking is deferred till COMMIT */
  u8 aAction[2];        /* ON DELETE and ON UPDATE actions, respectively */
  Trigger *apTrigger[2];/* Triggers for aAction[] actions */
  struct sColMap {      /* Mapping of columns in pFrom to columns in zTo */
    int iFrom;            /* Index of column in pFrom */
    char *zCol;           /* Name of column in zTo.  If NULL use PRIMARY KEY */
  } aCol[FLEXARRAY];      /* One entry for each of nCol columns */
};

/* The size (in bytes) of an FKey object holding N columns.  The answer
** does NOT include space to hold the zTo name. */
#define SZ_FKEY(N)  (offsetof(FKey,aCol)+(N)*sizeof(struct sColMap))

/*
** SQLite supports many different ways to resolve a constraint
** error.  ROLLBACK processing means that a constraint violation
** causes the operation in process to fail and for the current transaction
** to be rolled back.  ABORT processing means the operation in process
** fails and any prior changes from that one operation are backed out,

struct KeyInfo {
  u32 nRef;           /* Number of references to this KeyInfo object */
  u8 enc;             /* Text encoding - one of the SQLITE_UTF* values */
  u16 nKeyField;      /* Number of key columns in the index */
  u16 nAllField;      /* Total columns, including key plus others */
  sqlite3 *db;        /* The database connection */
  u8 *aSortFlags;     /* Sort order for each column. */
  CollSeq *aColl[FLEXARRAY]; /* Collating sequence for each term of the key */
};

/* The size (in bytes) of a KeyInfo object with up to N fields */
#define SZ_KEYINFO(N)  (offsetof(KeyInfo,aColl) + (N)*sizeof(CollSeq*))

/*
** Allowed bit values for entries in the KeyInfo.aSortFlags[] array.
*/
#define KEYINFO_ORDER_DESC    0x01    /* DESC sort order */
#define KEYINFO_ORDER_BIGNULL 0x02    /* NULL is larger than any other value */

/*

  u8 *aSortOrder;          /* for each column: True==DESC, False==ASC */
  const char **azColl;     /* Array of collation sequence names for index */
  Expr *pPartIdxWhere;     /* WHERE clause for partial indices */
  ExprList *aColExpr;      /* Column expressions */
  Pgno tnum;               /* DB Page containing root of this index */
  LogEst szIdxRow;         /* Estimated average row size in bytes */
  u16 nKeyCol;             /* Number of columns forming the key */
  u16 nColumn;             /* Nr columns in btree. Can be 2*Table.nCol */
  u8 onError;              /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  unsigned idxType:2;      /* 0:Normal 1:UNIQUE, 2:PRIMARY KEY, 3:IPK */
  unsigned bUnordered:1;   /* Use this index for == or IN queries only */
  unsigned uniqNotNull:1;  /* True if UNIQUE and NOT NULL for all columns */
  unsigned isResized:1;    /* True if resizeIndexObject() has been called */
  unsigned isCovering:1;   /* True if this is a covering index */
  unsigned noSkipScan:1;   /* Do not try to use skip-scan if true */
  unsigned hasStat1:1;     /* aiRowLogEst values come from sqlite_stat1 */
  unsigned bLowQual:1;     /* sqlite_stat1 says this is a low-quality index */
  unsigned bNoQuery:1;     /* Do not use this index to optimize queries */
  unsigned bAscKeyBug:1;   /* True if the bba7b69f9849b5bf bug applies */
  unsigned bIdxRowid:1;    /* One or more of the index keys is the ROWID */
  unsigned bHasVCol:1;     /* Index references one or more VIRTUAL columns */
  unsigned bHasExpr:1;     /* Index contains an expression, either a literal
                           ** expression, or a reference to a VIRTUAL column */
#ifdef SQLITE_ENABLE_STAT4
  int nSample;             /* Number of elements in aSample[] */
  int mxSample;            /* Number of slots allocated to aSample[] */
  int nSampleCol;          /* Size of IndexSample.anEq[] and so on */

** upwards into parent nodes.
*/
#define EP_Propagate (EP_Collate|EP_Subquery|EP_HasFunc)

/* Macros can be used to test, set, or clear bits in the
** Expr.flags field.
*/
#define ExprHasProperty(E,P)     (((E)->flags&(u32)(P))!=0)
#define ExprHasAllProperty(E,P)  (((E)->flags&(u32)(P))==(u32)(P))
#define ExprSetProperty(E,P)     (E)->flags|=(u32)(P)
#define ExprClearProperty(E,P)   (E)->flags&=~(u32)(P)
#define ExprAlwaysTrue(E)   (((E)->flags&(EP_OuterON|EP_IsTrue))==EP_IsTrue)
#define ExprAlwaysFalse(E)  (((E)->flags&(EP_OuterON|EP_IsFalse))==EP_IsFalse)
#define ExprIsFullSize(E)   (((E)->flags&(EP_Reduced|EP_TokenOnly))==0)

/* Macros used to ensure that the correct members of unions are accessed
** in Expr.
*/

      struct {             /* Used by any ExprList other than Parse.pConsExpr */
        u16 iOrderByCol;      /* For ORDER BY, column number in result set */
        u16 iAlias;           /* Index into Parse.aAlias[] for zName */
      } x;
      int iConstExprReg;   /* Register in which Expr value is cached. Used only
                           ** by Parse.pConstExpr */
    } u;
  } a[FLEXARRAY];          /* One slot for each expression in the list */
};

/* The size (in bytes) of an ExprList object that is big enough to hold
** as many as N expressions. */
#define SZ_EXPRLIST(N)  \
             (offsetof(ExprList,a) + (N)*sizeof(struct ExprList_item))

/*
** Allowed values for Expr.a.eEName
*/
#define ENAME_NAME  0       /* The AS clause of a result set */
#define ENAME_SPAN  1       /* Complete text of the result set expression */
#define ENAME_TAB   2       /* "DB.TABLE.NAME" for the result set */

**
** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
*/
struct IdList {
  int nId;         /* Number of identifiers on the list */
  struct IdList_item {
    char *zName;      /* Name of the identifier */
  } a[FLEXARRAY];
};

/* The size (in bytes) of an IdList object that can hold up to N IDs. */
#define SZ_IDLIST(N)  (offsetof(IdList,a)+(N)*sizeof(struct IdList_item))

/*
** Allowed values for IdList.eType, which determines which value of the a.u4
** is valid.
*/
#define EU4_NONE   0   /* Does not use IdList.a.u4 */
#define EU4_IDX    1   /* Uses IdList.a.u4.idx */
#define EU4_EXPR   2   /* Uses IdList.a.u4.pExpr -- NOT CURRENTLY USED */

** This object represents one or more tables that are the source of
** content for an SQL statement.  For example, a single SrcList object
** is used to hold the FROM clause of a SELECT statement.  SrcList also
** represents the target tables for DELETE, INSERT, and UPDATE statements.
**
*/
struct SrcList {
  int nSrc;             /* Number of tables or subqueries in the FROM clause */
  u32 nAlloc;           /* Number of entries allocated in a[] below */
  SrcItem a[FLEXARRAY]; /* One entry for each identifier on the list */
};

/* Size (in bytes) of a SrcList object that can hold as many as N
** SrcItem objects. */
#define SZ_SRCLIST(N) (offsetof(SrcList,a)+(N)*sizeof(SrcItem))

/* Size (in bytes( of a SrcList object that holds 1 SrcItem.  This is a
** special case of SZ_SRCITEM(1) that comes up often. */
#define SZ_SRCLIST_1  (offsetof(SrcList,a)+sizeof(SrcItem))

/*
** Permitted values of the SrcList.a.jointype field
*/
#define JT_INNER     0x01    /* Any kind of inner or cross join */
#define JT_CROSS     0x02    /* Explicit use of the CROSS keyword */
#define JT_NATURAL   0x04    /* True for a "natural" join */

** An instance of the With object represents a WITH clause containing
** one or more CTEs (common table expressions).
*/
struct With {
  int nCte;               /* Number of CTEs in the WITH clause */
  int bView;              /* Belongs to the outermost Select of a view */
  With *pOuter;           /* Containing WITH clause, or NULL */
  Cte a[FLEXARRAY];       /* For each CTE in the WITH clause.... */
};

/* The size (in bytes) of a With object that can hold as many
** as N different CTEs. */
#define SZ_WITH(N)  (offsetof(With,a) + (N)*sizeof(Cte))

/*
** The Cte object is not guaranteed to persist for the entire duration
** of code generation.  (The query flattener or other parser tree
** edits might delete it.)  The following object records information
** about each Common Table Expression that must be preserved for the
** duration of the parse.

/* Client data associated with sqlite3_set_clientdata() and
** sqlite3_get_clientdata().
*/
struct DbClientData {
  DbClientData *pNext;        /* Next in a linked list */
  void *pData;                /* The data */
  void (*xDestructor)(void*); /* Destructor.  Might be NULL */
  char zName[FLEXARRAY];      /* Name of this client data. MUST BE LAST */
};

/* The size (in bytes) of a DbClientData object that can has a name
** that is N bytes long, including the zero-terminator. */
#define SZ_DBCLIENTDATA(N) (offsetof(DbClientData,zName)+(N))

#ifdef SQLITE_DEBUG
/*
** An instance of the TreeView object is used for printing the content of
** data structures on sqlite3DebugPrintf() using a tree-like view.
*/
struct TreeView {

SQLITE_PRIVATE void sqlite3DeleteColumnNames(sqlite3*,Table*);
SQLITE_PRIVATE void sqlite3GenerateColumnNames(Parse *pParse, Select *pSelect);
SQLITE_PRIVATE int sqlite3ColumnsFromExprList(Parse*,ExprList*,i16*,Column**);
SQLITE_PRIVATE void sqlite3SubqueryColumnTypes(Parse*,Table*,Select*,char);
SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse*,Select*,char);
SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *, int);
SQLITE_PRIVATE Index *sqlite3PrimaryKeyIndex(Table*);
SQLITE_PRIVATE int sqlite3TableColumnToIndex(Index*, int);
#ifdef SQLITE_OMIT_GENERATED_COLUMNS
# define sqlite3TableColumnToStorage(T,X) (X)  /* No-op pass-through */
# define sqlite3StorageColumnToTable(T,X) (X)  /* No-op pass-through */
#else
SQLITE_PRIVATE   i16 sqlite3TableColumnToStorage(Table*, i16);
SQLITE_PRIVATE   i16 sqlite3StorageColumnToTable(Table*, i16);
#endif

SQLITE_PRIVATE void sqlite3SrcListFuncArgs(Parse*, SrcList*, ExprList*);
SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *, SrcItem *);
SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(Parse*,SrcList*);
SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse*, SrcList*);
SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3*, IdList*);
SQLITE_PRIVATE void sqlite3ClearOnOrUsing(sqlite3*, OnOrUsing*);
SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3*, SrcList*);
SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(sqlite3*,int,int,char**);
SQLITE_PRIVATE void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
                          Expr*, int, int, u8);
SQLITE_PRIVATE void sqlite3DropIndex(Parse*, SrcList*, int);
SQLITE_PRIVATE int sqlite3Select(Parse*, Select*, SelectDest*);
SQLITE_PRIVATE Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
                         Expr*,ExprList*,u32,Expr*);
SQLITE_PRIVATE void sqlite3SelectDelete(sqlite3*, Select*);

SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,const ExprList*,int);
SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,const SrcList*,int);
SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3*,const IdList*);
SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,const Select*,int);
SQLITE_PRIVATE FuncDef *sqlite3FunctionSearch(int,const char*);
SQLITE_PRIVATE void sqlite3InsertBuiltinFuncs(FuncDef*,int);
SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,u8,u8);
SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum*,sqlite3_value*,int);
SQLITE_PRIVATE int sqlite3AppendOneUtf8Character(char*, u32);
SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(void);
SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void);
SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void);
SQLITE_PRIVATE void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3*);
#if !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
SQLITE_PRIVATE   int sqlite3JsonTableFunctions(sqlite3*);
#endif

  "ENABLE_RBU",
#endif
#ifdef SQLITE_ENABLE_RTREE
  "ENABLE_RTREE",
#endif
#ifdef SQLITE_ENABLE_SESSION
  "ENABLE_SESSION",
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  "ENABLE_SETLK_TIMEOUT",
#endif
#ifdef SQLITE_ENABLE_SNAPSHOT
  "ENABLE_SNAPSHOT",
#endif
#ifdef SQLITE_ENABLE_SORTER_REFERENCES
  "ENABLE_SORTER_REFERENCES",
#endif

#endif
#ifdef SQLITE_EXTRA_IFNULLROW
  "EXTRA_IFNULLROW",
#endif
#ifdef SQLITE_EXTRA_INIT
  "EXTRA_INIT=" CTIMEOPT_VAL(SQLITE_EXTRA_INIT),
#endif
#ifdef SQLITE_EXTRA_INIT_MUTEXED
  "EXTRA_INIT_MUTEXED=" CTIMEOPT_VAL(SQLITE_EXTRA_INIT_MUTEXED),
#endif
#ifdef SQLITE_EXTRA_SHUTDOWN
  "EXTRA_SHUTDOWN=" CTIMEOPT_VAL(SQLITE_EXTRA_SHUTDOWN),
#endif
#ifdef SQLITE_FTS3_MAX_EXPR_DEPTH
  "FTS3_MAX_EXPR_DEPTH=" CTIMEOPT_VAL(SQLITE_FTS3_MAX_EXPR_DEPTH),
#endif
#ifdef SQLITE_FTS5_ENABLE_TEST_MI

  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 */

  /* Space is allocated for aType to hold at least 2*nField+1 entries:

  ** nField slots for aType[] and nField+1 array slots for aOffset[] */
  u32 aType[FLEXARRAY];    /* Type values record decode.  MUST BE LAST */
};

/*
** The size (in bytes) of a VdbeCursor object that has an nField value of N
** or less.  The value of SZ_VDBECURSOR(n) is guaranteed to be a multiple
** of 8.
*/
#define SZ_VDBECURSOR(N) \
    (ROUND8(offsetof(VdbeCursor,aType)) + ((N)+1)*sizeof(u64))

/* 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.

  Mem *pMem;              /* Memory cell used to store aggregate context */
  Vdbe *pVdbe;            /* The VM that owns this context */
  int iOp;                /* Instruction number of OP_Function */
  int isError;            /* Error code returned by the function. */
  u8 enc;                 /* Encoding to use for results */
  u8 skipFlag;            /* Skip accumulator loading if true */
  u16 argc;               /* Number of arguments */
  sqlite3_value *argv[FLEXARRAY]; /* Argument set */
};

/*
** The size (in bytes) of an sqlite3_context object that holds N
** argv[] arguments.
*/
#define SZ_CONTEXT(N)  \
   (offsetof(sqlite3_context,argv)+(N)*sizeof(sqlite3_value*))


/* The ScanStatus object holds a single value for the
** sqlite3_stmt_scanstatus() interface.
**
** aAddrRange[]:
**   This array is used by ScanStatus elements associated with EQP
**   notes that make an SQLITE_SCANSTAT_NCYCLE value available. It is

** sqlite3_preupdate_*() API functions.
*/
struct PreUpdate {
  Vdbe *v;
  VdbeCursor *pCsr;               /* Cursor to read old values from */
  int op;                         /* One of SQLITE_INSERT, UPDATE, DELETE */
  u8 *aRecord;                    /* old.* database record */
  KeyInfo *pKeyinfo;              /* Key information */
  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 oldipk;                     /* Memory cell holding "old" IPK value */
  Mem *aNew;                      /* Array of new.* values */
  Table *pTab;                    /* Schema object being updated */
  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
  sqlite3_value **apDflt;         /* Array of default values, if required */
  u8 keyinfoSpace[SZ_KEYINFO(0)]; /* Space to hold pKeyinfo[0] content */
};

/*
** 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.
**

SQLITE_PRIVATE int sqlite3LookasideUsed(sqlite3 *db, int *pHighwater){
  u32 nInit = countLookasideSlots(db->lookaside.pInit);
  u32 nFree = countLookasideSlots(db->lookaside.pFree);
#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
  nInit += countLookasideSlots(db->lookaside.pSmallInit);
  nFree += countLookasideSlots(db->lookaside.pSmallFree);
#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
  assert( db->lookaside.nSlot >= nInit+nFree );
  if( pHighwater ) *pHighwater = (int)(db->lookaside.nSlot - nInit);
  return (int)(db->lookaside.nSlot - (nInit+nFree));
}

/*
** Query status information for a single database connection
*/
SQLITE_API int sqlite3_db_status(
  sqlite3 *db,          /* The database connection whose status is desired */

    case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
      *pCurrent = 0;
      *pHighwater = (int)db->lookaside.anStat[op-SQLITE_DBSTATUS_LOOKASIDE_HIT];
      if( resetFlag ){
        db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
      }
      break;
    }

    /*

/*
** Return the number of days after the most recent Sunday.
**
** In other words, return the day of the week according
** to this code:
**
**   0=Sunday, 1=Monday, 2=Tuesday, ..., 6=Saturday
*/
static int daysAfterSunday(DateTime *pDate){
  assert( pDate->validJD );
  return (int)((pDate->iJD+129600000)/86400000) % 7;
}

/*

/*
** Include the primary Windows SDK header file.
*/
#include "windows.h"

#ifdef __CYGWIN__
# include <sys/cygwin.h>
# include <sys/stat.h> /* amalgamator: dontcache */
# include <unistd.h> /* amalgamator: dontcache */
# include <errno.h> /* amalgamator: dontcache */
#endif

/*
** Determine if we are dealing with Windows NT.
**
** We ought to be able to determine if we are compiling for Windows 9x or

#define etGENERIC     3 /* Floating or exponential, depending on exponent. %g */
#define etSIZE        4 /* Return number of characters processed so far. %n */
#define etSTRING      5 /* Strings. %s */
#define etDYNSTRING   6 /* Dynamically allocated strings. %z */
#define etPERCENT     7 /* Percent symbol. %% */
#define etCHARX       8 /* Characters. %c */
/* The rest are extensions, not normally found in printf() */
#define etESCAPE_q    9  /* Strings with '\'' doubled.  %q */
#define etESCAPE_Q    10 /* Strings with '\'' doubled and enclosed in '',
                            NULL pointers replaced by SQL NULL.  %Q */
#define etTOKEN       11 /* a pointer to a Token structure */
#define etSRCITEM     12 /* a pointer to a SrcItem */
#define etPOINTER     13 /* The %p conversion */
#define etESCAPE_w    14 /* %w -> Strings with '\"' doubled */
#define etORDINAL     15 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
#define etDECIMAL     16 /* %d or %u, but not %x, %o */

#define etINVALID     17 /* Any unrecognized conversion type */


/*
** An "etByte" is an 8-bit unsigned value.
*/
typedef unsigned char etByte;

static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
static const char aPrefix[] = "-x0\000X0";
static const et_info fmtinfo[] = {
  {  'd', 10, 1, etDECIMAL,    0,  0 },
  {  's',  0, 4, etSTRING,     0,  0 },
  {  'g',  0, 1, etGENERIC,    30, 0 },
  {  'z',  0, 4, etDYNSTRING,  0,  0 },
  {  'q',  0, 4, etESCAPE_q,   0,  0 },
  {  'Q',  0, 4, etESCAPE_Q,   0,  0 },
  {  'w',  0, 4, etESCAPE_w,   0,  0 },
  {  'c',  0, 0, etCHARX,      0,  0 },
  {  'o',  8, 0, etRADIX,      0,  2 },
  {  'u', 10, 0, etDECIMAL,    0,  0 },
  {  'x', 16, 0, etRADIX,      16, 1 },
  {  'X', 16, 0, etRADIX,      0,  4 },
#ifndef SQLITE_OMIT_FLOATING_POINT
  {  'f',  0, 1, etFLOAT,      0,  0 },

              }
            }
          }else{
            buf[0] = 0;
          }
        }else{
          unsigned int ch = va_arg(ap,unsigned int);


          length = sqlite3AppendOneUtf8Character(buf, ch);
















        }
        if( precision>1 ){
          i64 nPrior = 1;
          width -= precision-1;
          if( width>1 && !flag_leftjustify ){
            sqlite3_str_appendchar(pAccum, width-1, ' ');
            width = 0;

      adjust_width_for_utf8:
        if( flag_altform2 && width>0 ){
          /* Adjust width to account for extra bytes in UTF-8 characters */
          int ii = length - 1;
          while( ii>=0 ) if( (bufpt[ii--] & 0xc0)==0x80 ) width++;
        }
        break;
      case etESCAPE_q:          /* %q: Escape ' characters */
      case etESCAPE_Q:          /* %Q: Escape ' and enclose in '...' */
      case etESCAPE_w: {        /* %w: Escape " characters */
        i64 i, j, k, n;
        int needQuote = 0;
        char ch;

        char *escarg;
        char q;

        if( bArgList ){
          escarg = getTextArg(pArgList);
        }else{
          escarg = va_arg(ap,char*);
        }
        if( escarg==0 ){
          escarg = (xtype==etESCAPE_Q ? "NULL" : "(NULL)");
        }else if( xtype==etESCAPE_Q ){
          needQuote = 1;
        }
        if( xtype==etESCAPE_w ){
          q = '"';
          flag_alternateform = 0;
        }else{
          q = '\'';
        }
        /* For %q, %Q, and %w, the precision is the number of bytes (or
        ** characters if the ! flags is present) to use from the input.
        ** Because of the extra quoting characters inserted, the number
        ** of output characters may be larger than the precision.
        */
        k = precision;
        for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
          if( ch==q )  n++;
          if( flag_altform2 && (ch&0xc0)==0xc0 ){
            while( (escarg[i+1]&0xc0)==0x80 ){ i++; }
          }
        }
        if( flag_alternateform ){
          /* For %#q, do unistr()-style backslash escapes for
          ** all control characters, and for backslash itself.
          ** For %#Q, do the same but only if there is at least
          ** one control character. */
          u32 nBack = 0;
          u32 nCtrl = 0;
          for(k=0; k<i; k++){
            if( escarg[k]=='\\' ){
              nBack++;
            }else if( ((u8*)escarg)[k]<=0x1f ){
              nCtrl++;
            }
          }
          if( nCtrl || xtype==etESCAPE_q ){
            n += nBack + 5*nCtrl;
            if( xtype==etESCAPE_Q ){
              n += 10;
              needQuote = 2;
            }
          }else{
            flag_alternateform = 0;
          }
        }
        n += i + 3;
        if( n>etBUFSIZE ){
          bufpt = zExtra = printfTempBuf(pAccum, n);
          if( bufpt==0 ) return;
        }else{
          bufpt = buf;
        }
        j = 0;
        if( needQuote ){
          if( needQuote==2 ){
            memcpy(&bufpt[j], "unistr('", 8);
            j += 8;
          }else{
            bufpt[j++] = '\'';
          }
        }
        k = i;
        if( flag_alternateform ){
          for(i=0; i<k; i++){
            bufpt[j++] = ch = escarg[i];
            if( ch==q ){
              bufpt[j++] = ch;
            }else if( ch=='\\' ){
              bufpt[j++] = '\\';
            }else if( ((unsigned char)ch)<=0x1f ){
              bufpt[j-1] = '\\';
              bufpt[j++] = 'u';
              bufpt[j++] = '0';
              bufpt[j++] = '0';
              bufpt[j++] = ch>=0x10 ? '1' : '0';
              bufpt[j++] = "0123456789abcdef"[ch&0xf];
            }
          }
        }else{
          for(i=0; i<k; i++){
            bufpt[j++] = ch = escarg[i];
            if( ch==q ) bufpt[j++] = ch;
          }
        }
        if( needQuote ){
          bufpt[j++] = '\'';
          if( needQuote==2 ) bufpt[j++] = ')';
        }
        bufpt[j] = 0;
        length = j;
        goto adjust_width_for_utf8;
      }
      case etTOKEN: {
        if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
        if( flag_alternateform ){

  va_start(ap,zFormat);
  sqlite3_str_vappendf(&acc, zFormat, ap);
  va_end(ap);
  zBuf[acc.nChar] = 0;
  return zBuf;
}

/* Maximum size of an sqlite3_log() message. */
#if defined(SQLITE_MAX_LOG_MESSAGE)
  /* Leave the definition as supplied */
#elif SQLITE_PRINT_BUF_SIZE*10>10000
# define SQLITE_MAX_LOG_MESSAGE 10000
#else
# define SQLITE_MAX_LOG_MESSAGE (SQLITE_PRINT_BUF_SIZE*10)
#endif

/*
** This is the routine that actually formats the sqlite3_log() message.
** We house it in a separate routine from sqlite3_log() to avoid using
** stack space on small-stack systems when logging is disabled.
**
** sqlite3_log() must render into a static buffer.  It cannot dynamically
** allocate memory because it might be called while the memory allocator
** mutex is held.
**
** sqlite3_str_vappendf() might ask for *temporary* memory allocations for
** certain format characters (%q) or for very large precisions or widths.
** Care must be taken that any sqlite3_log() calls that occur while the
** memory mutex is held do not use these mechanisms.
*/
static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
  StrAccum acc;                          /* String accumulator */
  char zMsg[SQLITE_MAX_LOG_MESSAGE];     /* Complete log message */

  sqlite3StrAccumInit(&acc, 0, zMsg, sizeof(zMsg), 0);
  sqlite3_str_vappendf(&acc, zFormat, ap);
  sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
                           sqlite3StrAccumFinish(&acc));
}

  }else{                                                            \
    *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03));              \
    *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
    *zOut++ = (u8)(0x00DC + ((c>>8)&0x03));                         \
    *zOut++ = (u8)(c&0x00FF);                                       \
  }                                                                 \
}

/*
** Write a single UTF8 character whose value is v into the
** buffer starting at zOut.  zOut must be sized to hold at
** least for bytes.  Return the number of bytes needed
** to encode the new character.
*/
SQLITE_PRIVATE int sqlite3AppendOneUtf8Character(char *zOut, u32 v){
  if( v<0x00080 ){
    zOut[0] = (u8)(v & 0xff);
    return 1;
  }
  if( v<0x00800 ){
    zOut[0] = 0xc0 + (u8)((v>>6) & 0x1f);
    zOut[1] = 0x80 + (u8)(v & 0x3f);
    return 2;
  }
  if( v<0x10000 ){
    zOut[0] = 0xe0 + (u8)((v>>12) & 0x0f);
    zOut[1] = 0x80 + (u8)((v>>6) & 0x3f);
    zOut[2] = 0x80 + (u8)(v & 0x3f);
    return 3;
  }
  zOut[0] = 0xf0 + (u8)((v>>18) & 0x07);
  zOut[1] = 0x80 + (u8)((v>>12) & 0x3f);
  zOut[2] = 0x80 + (u8)((v>>6) & 0x3f);
  zOut[3] = 0x80 + (u8)(v & 0x3f);
  return 4;
}

/*
** Translate a single UTF-8 character.  Return the unicode value.
**
** During translation, assume that the byte that zTerm points
** is a 0x00.
**

SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *zIn, int nByte, int nChar){
  int c;
  unsigned char const *z = zIn;
  unsigned char const *zEnd = &z[nByte-1];
  int n = 0;

  if( SQLITE_UTF16NATIVE==SQLITE_UTF16LE ) z++;
  while( n<nChar && z<=zEnd ){
    c = z[0];
    z += 2;
    if( c>=0xd8 && c<0xdc && z<=zEnd && z[0]>=0xdc && z[0]<0xe0 ) z += 2;
    n++;
  }
  return (int)(z-(unsigned char const *)zIn)
              - (SQLITE_UTF16NATIVE==SQLITE_UTF16LE);

  }
  *pA = iA*iB;
  return 0;
#endif
}

/*
** Compute the absolute value of a 32-bit signed integer, if possible.  Or
** if the integer has a value of -2147483648, return +2147483647
*/
SQLITE_PRIVATE int sqlite3AbsInt32(int x){
  if( x>=0 ) return x;
  if( x==(int)0x80000000 ) return 0x7fffffff;
  return -x;
}

  int openFlags;                      /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  unsigned iBusyTimeout;              /* Wait this many millisec on locks */
  int bBlockOnConnect;                /* True to block for SHARED locks */
#endif
#if OS_VXWORKS
  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifdef SQLITE_DEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated

      if( rc<0 ) return rc;
      pInode->bProcessLock = 1;
      pInode->nLock++;
    }else{
      rc = 0;
    }
  }else{
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( pFile->bBlockOnConnect && pLock->l_type==F_RDLCK
     && pLock->l_start==SHARED_FIRST && pLock->l_len==SHARED_SIZE
    ){
      rc = osFcntl(pFile->h, F_SETLKW, pLock);
    }else
#endif
    rc = osSetPosixAdvisoryLock(pFile->h, pLock, pFile);
  }
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one

    case SQLITE_FCNTL_HAS_MOVED: {
      *(int*)pArg = fileHasMoved(pFile);
      return SQLITE_OK;
    }
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    case SQLITE_FCNTL_LOCK_TIMEOUT: {
      int iOld = pFile->iBusyTimeout;
      int iNew = *(int*)pArg;
#if SQLITE_ENABLE_SETLK_TIMEOUT==1
      pFile->iBusyTimeout = iNew<0 ? 0x7FFFFFFF : (unsigned)iNew;
#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
      pFile->iBusyTimeout = !!(*(int*)pArg);
#else
# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
#endif
      *(int*)pArg = iOld;
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_BLOCK_ON_CONNECT: {
      int iNew = *(int*)pArg;
      pFile->bBlockOnConnect = iNew;
      return SQLITE_OK;
    }
#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */
#if SQLITE_MAX_MMAP_SIZE>0
    case SQLITE_FCNTL_MMAP_SIZE: {
      i64 newLimit = *(i64*)pArg;
      int rc = SQLITE_OK;
      if( newLimit>sqlite3GlobalConfig.mxMmap ){
        newLimit = sqlite3GlobalConfig.mxMmap;
      }

  **
  ** In other words, if this is a blocking lock, none of the locks that
  ** occur later in the above list than the lock being obtained may be
  ** held.
  **
  ** It is not permitted to block on the RECOVER lock.
  */
#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && defined(SQLITE_DEBUG)
  {
    u16 lockMask = (p->exclMask|p->sharedMask);
    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
          (ofst!=2)                                   /* not RECOVER */
       && (ofst!=1 || lockMask==0 || lockMask==2)
       && (ofst!=0 || lockMask<3)
       && (ofst<3  || lockMask<(1<<ofst))

#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 conjunction 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 SQLITE_MAX_MMAP_SIZE>0
  int nFetchOut;                /* Number of outstanding xFetch references */
  HANDLE hMap;                  /* Handle for accessing memory mapping */
  void *pMapRegion;             /* Area memory mapped */
  sqlite3_int64 mmapSize;       /* Size of mapped region */
  sqlite3_int64 mmapSizeMax;    /* Configured FCNTL_MMAP_SIZE value */
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  DWORD iBusyTimeout;        /* Wait this many millisec on locks */
  int bBlockOnConnect;
#endif
};

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
# define winFileBusyTimeout(pDbFd) pDbFd->iBusyTimeout
#else
# define winFileBusyTimeout(pDbFd) 0
#endif

/*
** The winVfsAppData structure is used for the pAppData member for all of the
** Win32 VFS variants.
*/
typedef struct winVfsAppData winVfsAppData;
struct winVfsAppData {

#if SQLITE_OS_WINCE
  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
#else
  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
#endif

#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(const FILETIME*, \
        LPFILETIME))aSyscall[11].pCurrent)

#if SQLITE_OS_WINCE
  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
#else
  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
#endif

#define osFileTimeToSystemTime ((BOOL(WINAPI*)(const FILETIME*, \
        LPSYSTEMTIME))aSyscall[12].pCurrent)

  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },

#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[13].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)

#else
  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
        LPWSTR*))aSyscall[25].pCurrent)

/*
** For GetLastError(), MSDN says:
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
  { "GetLastError",            (SYSCALL)GetLastError,            0 },

#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)

#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
#if SQLITE_OS_WINCE
  /* The GetProcAddressA() routine is only available on Windows CE. */

#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
  { "LockFile",                (SYSCALL)LockFile,                0 },
#else
  { "LockFile",                (SYSCALL)0,                       0 },
#endif

#if !defined(osLockFile) && defined(SQLITE_WIN32_HAS_ANSI)
#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[47].pCurrent)
#endif

#if !SQLITE_OS_WINCE
  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },
#else

  { "Sleep",                   (SYSCALL)0,                       0 },
#endif

#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[55].pCurrent)

  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },

#define osSystemTimeToFileTime ((BOOL(WINAPI*)(const SYSTEMTIME*, \
        LPFILETIME))aSyscall[56].pCurrent)

#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },
#else
  { "UnlockFile",              (SYSCALL)0,                       0 },
#endif

#if !defined(osUnlockFile) && defined(SQLITE_WIN32_HAS_ANSI)
#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[57].pCurrent)
#endif

#if !SQLITE_OS_WINCE
  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },
#else

#else
  { "CreateEventExW",          (SYSCALL)0,                       0 },
#endif

#define osCreateEventExW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,LPCWSTR, \
        DWORD,DWORD))aSyscall[62].pCurrent)


/*
** For WaitForSingleObject(), MSDN says:

**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
  { "WaitForSingleObject",     (SYSCALL)WaitForSingleObject,     0 },


#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[63].pCurrent)

#if !SQLITE_OS_WINCE
  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
#else

#else
  { "FlushViewOfFile",          (SYSCALL)0,                      0 },
#endif

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

/*
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined, we require CreateEvent()
** to implement blocking locks with timeouts. MSDN says:
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  { "CreateEvent",              (SYSCALL)CreateEvent,            0 },
#else
  { "CreateEvent",              (SYSCALL)0,                      0 },
#endif

#define osCreateEvent ( \
    (HANDLE(WINAPI*) (LPSECURITY_ATTRIBUTES,BOOL,BOOL,LPCSTR)) \
    aSyscall[80].pCurrent \
)

/*
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined, we require CancelIo()
** for the case where a timeout expires and a lock request must be
** cancelled.
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  { "CancelIo",                 (SYSCALL)CancelIo,               0 },
#else
  { "CancelIo",                 (SYSCALL)0,                      0 },
#endif

#define osCancelIo ((BOOL(WINAPI*)(HANDLE))aSyscall[81].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE) && defined(_WIN32)
  { "GetModuleHandleW",         (SYSCALL)GetModuleHandleW,       0 },
#else
  { "GetModuleHandleW",         (SYSCALL)0,                      0 },
#endif

#define osGetModuleHandleW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[82].pCurrent)

#ifndef _WIN32
  { "getenv",                   (SYSCALL)getenv,                 0 },
#else
  { "getenv",                   (SYSCALL)0,                      0 },
#endif

#define osGetenv ((const char *(*)(const char *))aSyscall[83].pCurrent)

#ifndef _WIN32
  { "getcwd",                   (SYSCALL)getcwd,                 0 },
#else
  { "getcwd",                   (SYSCALL)0,                      0 },
#endif

#define osGetcwd ((char*(*)(char*,size_t))aSyscall[84].pCurrent)

#ifndef _WIN32
  { "readlink",                 (SYSCALL)readlink,               0 },
#else
  { "readlink",                 (SYSCALL)0,                      0 },
#endif

#define osReadlink ((ssize_t(*)(const char*,char*,size_t))aSyscall[85].pCurrent)

#ifndef _WIN32
  { "lstat",                    (SYSCALL)lstat,                  0 },
#else
  { "lstat",                    (SYSCALL)0,                      0 },
#endif

#define osLstat ((int(*)(const char*,struct stat*))aSyscall[86].pCurrent)

#ifndef _WIN32
  { "__errno",                  (SYSCALL)__errno,                0 },
#else
  { "__errno",                  (SYSCALL)0,                      0 },
#endif

#define osErrno (*((int*(*)(void))aSyscall[87].pCurrent)())

#ifndef _WIN32
  { "cygwin_conv_path",         (SYSCALL)cygwin_conv_path,       0 },
#else
  { "cygwin_conv_path",         (SYSCALL)0,                      0 },
#endif

#define osCygwin_conv_path ((size_t(*)(unsigned int, \
    const void *, void *, size_t))aSyscall[88].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.

  }
  sqlite3_mutex_leave(pMem);
  sqlite3_mutex_leave(pMainMtx);
  return rc;
}
#endif /* SQLITE_WIN32_MALLOC */

#ifdef _WIN32
/*
** This function outputs the specified (ANSI) string to the Win32 debugger
** (if available).
*/

SQLITE_API void sqlite3_win32_write_debug(const char *zBuf, int nBuf){
  char zDbgBuf[SQLITE_WIN32_DBG_BUF_SIZE];

    memcpy(zDbgBuf, zBuf, nMin);
    fprintf(stderr, "%s", zDbgBuf);
  }else{
    fprintf(stderr, "%s", zBuf);
  }
#endif
}
#endif /* _WIN32 */

/*
** The following routine suspends the current thread for at least ms
** milliseconds.  This is equivalent to the Win32 Sleep() interface.
*/
#if SQLITE_OS_WINRT
static HANDLE sleepObj = NULL;

    osGetVersionExW(&sInfo);
    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#endif
  }
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#elif SQLITE_TEST
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2
      || osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0
  ;
#else
  /*
  ** NOTE: All sub-platforms where the GetVersionEx[AW] functions are
  **       deprecated are always assumed to be based on the NT kernel.
  */
  return 1;
#endif

}

SQLITE_PRIVATE void sqlite3MemSetDefault(void){
  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
}
#endif /* SQLITE_WIN32_MALLOC */

#ifdef _WIN32
/*
** Convert a UTF-8 string to Microsoft Unicode.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static LPWSTR winUtf8ToUnicode(const char *zText){
  int nChar;

                                nChar);
  if( nChar==0 ){
    sqlite3_free(zWideText);
    zWideText = 0;
  }
  return zWideText;
}
#endif /* _WIN32 */

/*
** Convert a Microsoft Unicode string to UTF-8.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static char *winUnicodeToUtf8(LPCWSTR zWideText){

/*
** Convert an ANSI string to Microsoft Unicode, using the ANSI or OEM
** code page.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static LPWSTR winMbcsToUnicode(const char *zText, int useAnsi){
  int nWideChar;
  LPWSTR zMbcsText;
  int codepage = useAnsi ? CP_ACP : CP_OEMCP;

  nWideChar = osMultiByteToWideChar(codepage, 0, zText, -1, NULL,
                                0);
  if( nWideChar==0 ){
    return 0;
  }
  zMbcsText = sqlite3MallocZero( nWideChar*sizeof(WCHAR) );
  if( zMbcsText==0 ){
    return 0;
  }
  nWideChar = osMultiByteToWideChar(codepage, 0, zText, -1, zMbcsText,
                                nWideChar);
  if( nWideChar==0 ){
    sqlite3_free(zMbcsText);
    zMbcsText = 0;
  }
  return zMbcsText;
}

#ifdef _WIN32
/*
** Convert a Microsoft Unicode string to a multi-byte character string,
** using the ANSI or OEM code page.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static char *winUnicodeToMbcs(LPCWSTR zWideText, int useAnsi){

                                nByte, 0, 0);
  if( nByte == 0 ){
    sqlite3_free(zText);
    zText = 0;
  }
  return zText;
}
#endif /* _WIN32 */

/*
** Convert a multi-byte character string to UTF-8.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static char *winMbcsToUtf8(const char *zText, int useAnsi){
  char *zTextUtf8;
  LPWSTR zTmpWide;

  zTmpWide = winMbcsToUnicode(zText, useAnsi);
  if( zTmpWide==0 ){
    return 0;
  }
  zTextUtf8 = winUnicodeToUtf8(zTmpWide);
  sqlite3_free(zTmpWide);
  return zTextUtf8;
}

#ifdef _WIN32
/*
** Convert a UTF-8 string to a multi-byte character string.
**
** Space to hold the returned string is obtained from sqlite3_malloc().
*/
static char *winUtf8ToMbcs(const char *zText, int useAnsi){
  char *zTextMbcs;

  }
#endif
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  return winUnicodeToUtf8(zWideText);
}
#endif /* _WIN32 */

/*
** This is a public wrapper for the winMbcsToUtf8() function.
*/
SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zText){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !zText ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  return winMbcsToUtf8(zText, osAreFileApisANSI());
}

#ifdef _WIN32
/*
** This is a public wrapper for the winMbcsToUtf8() function.
*/
SQLITE_API char *sqlite3_win32_mbcs_to_utf8_v2(const char *zText, int useAnsi){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !zText ){
    (void)SQLITE_MISUSE_BKPT;

*/
SQLITE_API int sqlite3_win32_set_directory(
  unsigned long type, /* Identifier for directory being set or reset */
  void *zValue        /* New value for directory being set or reset */
){
  return sqlite3_win32_set_directory16(type, zValue);
}
#endif /* _WIN32 */

/*
** The return value of winGetLastErrorMsg
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated).
*/
static int winGetLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){

#else
  if( osIsNT() ){
    OVERLAPPED ovlp;
    memset(&ovlp, 0, sizeof(OVERLAPPED));
    ovlp.Offset = offsetLow;
    ovlp.OffsetHigh = offsetHigh;
    return osLockFileEx(*phFile, flags, 0, numBytesLow, numBytesHigh, &ovlp);
#ifdef SQLITE_WIN32_HAS_ANSI
  }else{
    return osLockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
                      numBytesHigh);
#endif
  }
#endif
}

/*
** Lock a region of nByte bytes starting at offset offset of file hFile.
** Take an EXCLUSIVE lock if parameter bExclusive is true, or a SHARED lock
** otherwise. If nMs is greater than zero and the lock cannot be obtained
** immediately, block for that many ms before giving up.
**
** This function returns SQLITE_OK if the lock is obtained successfully. If
** some other process holds the lock, SQLITE_BUSY is returned if nMs==0, or
** SQLITE_BUSY_TIMEOUT otherwise. Or, if an error occurs, SQLITE_IOERR.
*/
static int winHandleLockTimeout(
  HANDLE hFile,
  DWORD offset,
  DWORD nByte,
  int bExcl,
  DWORD nMs
){
  DWORD flags = LOCKFILE_FAIL_IMMEDIATELY | (bExcl?LOCKFILE_EXCLUSIVE_LOCK:0);
  int rc = SQLITE_OK;
  BOOL ret;

  if( !osIsNT() ){
    ret = winLockFile(&hFile, flags, offset, 0, nByte, 0);
  }else{
    OVERLAPPED ovlp;
    memset(&ovlp, 0, sizeof(OVERLAPPED));
    ovlp.Offset = offset;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( nMs!=0 ){
      flags &= ~LOCKFILE_FAIL_IMMEDIATELY;
    }
    ovlp.hEvent = osCreateEvent(NULL, TRUE, FALSE, NULL);
    if( ovlp.hEvent==NULL ){
      return SQLITE_IOERR_LOCK;
    }
#endif

    ret = osLockFileEx(hFile, flags, 0, nByte, 0, &ovlp);

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    /* If SQLITE_ENABLE_SETLK_TIMEOUT is defined, then the file-handle was
    ** opened with FILE_FLAG_OVERHEAD specified. In this case, the call to
    ** LockFileEx() may fail because the request is still pending. This can
    ** happen even if LOCKFILE_FAIL_IMMEDIATELY was specified.
    **
    ** If nMs is 0, then LOCKFILE_FAIL_IMMEDIATELY was set in the flags
    ** passed to LockFileEx(). In this case, if the operation is pending,
    ** block indefinitely until it is finished.
    **
    ** Otherwise, wait for up to nMs ms for the operation to finish. nMs
    ** may be set to INFINITE.
    */
    if( !ret && GetLastError()==ERROR_IO_PENDING ){
      DWORD nDelay = (nMs==0 ? INFINITE : nMs);
      DWORD res = osWaitForSingleObject(ovlp.hEvent, nDelay);
      if( res==WAIT_OBJECT_0 ){
        ret = TRUE;
      }else if( res==WAIT_TIMEOUT ){
        rc = SQLITE_BUSY_TIMEOUT;
      }else{
        /* Some other error has occurred */
        rc = SQLITE_IOERR_LOCK;
      }

      /* If it is still pending, cancel the LockFileEx() call. */
      osCancelIo(hFile);
    }

    osCloseHandle(ovlp.hEvent);
#endif
  }

  if( rc==SQLITE_OK && !ret ){
    rc = SQLITE_BUSY;
  }
  return rc;
}

/*
** Unlock a file region.
 */
static BOOL winUnlockFile(
  LPHANDLE phFile,
  DWORD offsetLow,

#else
  if( osIsNT() ){
    OVERLAPPED ovlp;
    memset(&ovlp, 0, sizeof(OVERLAPPED));
    ovlp.Offset = offsetLow;
    ovlp.OffsetHigh = offsetHigh;
    return osUnlockFileEx(*phFile, 0, numBytesLow, numBytesHigh, &ovlp);
#ifdef SQLITE_WIN32_HAS_ANSI
  }else{
    return osUnlockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
                        numBytesHigh);
#endif
  }
#endif
}

/*
** Remove an nByte lock starting at offset iOff from HANDLE h.
*/
static int winHandleUnlock(HANDLE h, int iOff, int nByte){
  BOOL ret = winUnlockFile(&h, iOff, 0, nByte, 0);
  return (ret ? SQLITE_OK : SQLITE_IOERR_UNLOCK);
}

/*****************************************************************************
** The next group of routines implement the I/O methods specified
** by the sqlite3_io_methods object.
******************************************************************************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_SET_FILE_POINTER
# define INVALID_SET_FILE_POINTER ((DWORD)-1)
#endif

/*
** Seek the file handle h to offset nByte of the file.
**
** If successful, return SQLITE_OK. Or, if an error occurs, return an SQLite

** error code.
*/
static int winHandleSeek(HANDLE h, sqlite3_int64 iOffset){
  int rc = SQLITE_OK;             /* Return value */

#if !SQLITE_OS_WINRT
  LONG upperBits;                 /* Most sig. 32 bits of new offset */
  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
  DWORD dwRet;                    /* Value returned by SetFilePointer() */




  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  dwRet = osSetFilePointer(h, lowerBits, &upperBits, FILE_BEGIN);

  /* API oddity: If successful, SetFilePointer() returns a dword
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN,
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine
  ** whether an error has actually occurred, it is also necessary to call
  ** GetLastError().  */



  if( dwRet==INVALID_SET_FILE_POINTER ){
    DWORD lastErrno = osGetLastError();
    if( lastErrno!=NO_ERROR ){
      rc = SQLITE_IOERR_SEEK;



    }
  }


#else

  /* This implementation works for WinRT. */


  LARGE_INTEGER x;                /* The new offset */
  BOOL bRet;                      /* Value returned by SetFilePointerEx() */

  x.QuadPart = iOffset;
  bRet = osSetFilePointerEx(h, x, 0, FILE_BEGIN);

  if(!bRet){

    rc = SQLITE_IOERR_SEEK;
  }
#endif

  OSTRACE(("SEEK file=%p, offset=%lld rc=%s\n", h, iOffset, sqlite3ErrName(rc)));
  return rc;
}

/*
** Move the current position of the file handle passed as the first
** argument to offset iOffset within the file. If successful, return 0.
** Otherwise, set pFile->lastErrno and return non-zero.
*/
static int winSeekFile(winFile *pFile, sqlite3_int64 iOffset){
  int rc;

  rc = winHandleSeek(pFile->h, iOffset);
  if( rc!=SQLITE_OK ){
    pFile->lastErrno = osGetLastError();
    winLogError(rc, pFile->lastErrno, "winSeekFile", pFile->zPath);
  }
  return rc;

}


#if SQLITE_MAX_MMAP_SIZE>0
/* Forward references to VFS helper methods used for memory mapped files */
static int winMapfile(winFile*, sqlite3_int64);
static int winUnmapfile(winFile*);
#endif

  }else{
    winLogIoerr(nRetry, __LINE__);
  }
  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
           osGetCurrentProcessId(), pFile, pFile->h));
  return SQLITE_OK;
}

/*
** Truncate the file opened by handle h to nByte bytes in size.
*/
static int winHandleTruncate(HANDLE h, sqlite3_int64 nByte){
  int rc = SQLITE_OK;             /* Return code */
  rc = winHandleSeek(h, nByte);
  if( rc==SQLITE_OK ){
    if( 0==osSetEndOfFile(h) ){
      rc = SQLITE_IOERR_TRUNCATE;
    }
  }
  return rc;
}

/*
** Determine the size in bytes of the file opened by the handle passed as
** the first argument.
*/
static int winHandleSize(HANDLE h, sqlite3_int64 *pnByte){
  int rc = SQLITE_OK;

#if SQLITE_OS_WINRT
  FILE_STANDARD_INFO info;
  BOOL b;
  b = osGetFileInformationByHandleEx(h, FileStandardInfo, &info, sizeof(info));
  if( b ){
    *pnByte = info.EndOfFile.QuadPart;
  }else{
    rc = SQLITE_IOERR_FSTAT;
  }
#else
  DWORD upperBits = 0;
  DWORD lowerBits = 0;

  assert( pnByte );
  lowerBits = osGetFileSize(h, &upperBits);
  *pnByte = (((sqlite3_int64)upperBits)<<32) + lowerBits;
  if( lowerBits==INVALID_FILE_SIZE && osGetLastError()!=NO_ERROR ){
    rc = SQLITE_IOERR_FSTAT;
  }
#endif

  return rc;
}

/*
** Close the handle passed as the only argument.
*/
static void winHandleClose(HANDLE h){
  if( h!=INVALID_HANDLE_VALUE ){
    osCloseHandle(h);
  }
}

/*
** Truncate an open file to a specified size
*/
static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
  winFile *pFile = (winFile*)id;  /* File handle object */
  int rc = SQLITE_OK;             /* Return code for this function */

#endif

/*
** Acquire a reader lock.
** Different API routines are called depending on whether or not this
** is Win9x or WinNT.
*/
static int winGetReadLock(winFile *pFile, int bBlock){
  int res;
  DWORD mask = ~(bBlock ? LOCKFILE_FAIL_IMMEDIATELY : 0);
  OSTRACE(("READ-LOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
  if( osIsNT() ){
#if SQLITE_OS_WINCE
    /*
    ** NOTE: Windows CE is handled differently here due its lack of the Win32
    **       API LockFileEx.
    */
    res = winceLockFile(&pFile->h, SHARED_FIRST, 0, 1, 0);
#else
    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS&mask, SHARED_FIRST, 0,
                      SHARED_SIZE, 0);
#endif
  }
#ifdef SQLITE_WIN32_HAS_ANSI
  else{
    int lk;
    sqlite3_randomness(sizeof(lk), &lk);
    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS&mask,
                      SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
  }
#endif
  if( res == 0 ){
    pFile->lastErrno = osGetLastError();
    /* No need to log a failure to lock */
  }

  /* Make sure the locking sequence is correct
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );

  /* Lock the PENDING_LOCK byte if we need to acquire an EXCLUSIVE lock or
  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
  ** the PENDING_LOCK byte is temporary.
  */
  newLocktype = pFile->locktype;
  if( locktype==SHARED_LOCK
   || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
  ){
    int cnt = 3;

    /* Flags for the LockFileEx() call. This should be an exclusive lock if
    ** this call is to obtain EXCLUSIVE, or a shared lock if this call is to
    ** obtain SHARED.  */
    int flags = LOCKFILE_FAIL_IMMEDIATELY;
    if( locktype==EXCLUSIVE_LOCK ){
      flags |= LOCKFILE_EXCLUSIVE_LOCK;
    }
    while( cnt>0 ){
      /* Try 3 times to get the pending lock.  This is needed to work
      ** around problems caused by indexing and/or anti-virus software on
      ** Windows systems.
      **
      ** If you are using this code as a model for alternative VFSes, do not
      ** copy this retry logic.  It is a hack intended for Windows only.  */
      res = winLockFile(&pFile->h, flags, PENDING_BYTE, 0, 1, 0);
      if( res ) break;

      lastErrno = osGetLastError();
      OSTRACE(("LOCK-PENDING-FAIL file=%p, count=%d, result=%d\n",
            pFile->h, cnt, res
      ));

      if( lastErrno==ERROR_INVALID_HANDLE ){
        pFile->lastErrno = lastErrno;
        rc = SQLITE_IOERR_LOCK;
        OSTRACE(("LOCK-FAIL file=%p, count=%d, rc=%s\n",
              pFile->h, cnt, sqlite3ErrName(rc)
        ));
        return rc;
      }

      cnt--;
      if( cnt>0 ) sqlite3_win32_sleep(1);
    }
    gotPendingLock = res;



  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res ){
    assert( pFile->locktype==NO_LOCK );
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    res = winGetReadLock(pFile, pFile->bBlockOnConnect);
#else
    res = winGetReadLock(pFile, 0);
#endif
    if( res ){
      newLocktype = SHARED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

    (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, 0);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){

  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(("UNLOCK file=%p, oldLock=%d(%d), newLock=%d\n",
           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !winGetReadLock(pFile, 0) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
                       "winUnlock", pFile->zPath);
    }
  }
  if( type>=RESERVED_LOCK ){

          rc = winMapfile(pFile, -1);
        }
      }
      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
      return rc;
    }
#endif

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    case SQLITE_FCNTL_LOCK_TIMEOUT: {
      int iOld = pFile->iBusyTimeout;
      int iNew = *(int*)pArg;
#if SQLITE_ENABLE_SETLK_TIMEOUT==1
      pFile->iBusyTimeout = (iNew < 0) ? INFINITE : (DWORD)iNew;
#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
      pFile->iBusyTimeout = (DWORD)(!!iNew);
#else
# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
#endif
      *(int*)pArg = iOld;
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_BLOCK_ON_CONNECT: {
      int iNew = *(int*)pArg;
      pFile->bBlockOnConnect = iNew;
      return SQLITE_OK;
    }
#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */

  }
  OSTRACE(("FCNTL file=%p, rc=SQLITE_NOTFOUND\n", pFile->h));
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for

** this object or while reading or writing the following fields:
**
**      nRef
**      pNext
**
** The following fields are read-only after the object is created:
**

**      zFilename
**
** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
** winShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
** File-handle hSharedShm is used to (a) take the DMS lock, (b) truncate
** the *-shm file if the DMS-locking protocol demands it, and (c) map
** regions of the *-shm file into memory using MapViewOfFile() or
** similar. Other locks are taken by individual clients using the
** winShm.hShm handles.
*/
struct winShmNode {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  char *zFilename;           /* Name of the file */
  HANDLE hSharedShm;         /* File handle open on zFilename */

  int isUnlocked;            /* DMS lock has not yet been obtained */
  int isReadonly;            /* True if read-only */
  int szRegion;              /* Size of shared-memory regions */
  int nRegion;               /* Size of array apRegion */



  struct ShmRegion {
    HANDLE hMap;             /* File handle from CreateFileMapping */
    void *pMap;
  } *aRegion;
  DWORD lastErrno;           /* The Windows errno from the last I/O error */

  int nRef;                  /* Number of winShm objects pointing to this */

  winShmNode *pNext;         /* Next in list of all winShmNode objects */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 nextShmId;              /* Next available winShm.id value */
#endif
};

/*
** A global array of all winShmNode objects.
**
** The winShmMutexHeld() must be true while reading or writing this list.
*/
static winShmNode *winShmNodeList = 0;

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection. There is one such structure for each





** winFile open on a wal mode database.



*/
struct winShm {
  winShmNode *pShmNode;      /* The underlying winShmNode object */


  u16 sharedMask;            /* Mask of shared locks held */
  u16 exclMask;              /* Mask of exclusive locks held */
  HANDLE hShm;               /* File-handle on *-shm file. For locking. */
  int bReadonly;             /* True if hShm is opened read-only */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 id;                     /* Id of this connection with its winShmNode */
#endif
};

/*
** Constants used for locking
*/
#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */













































/* Forward references to VFS methods */
static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
static int winDelete(sqlite3_vfs *,const char*,int);

/*
** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
**

                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
        UNUSED_VARIABLE_VALUE(bRc);
        bRc = osCloseHandle(p->aRegion[i].hMap);
        OSTRACE(("SHM-PURGE-CLOSE pid=%lu, region=%d, rc=%s\n",
                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
        UNUSED_VARIABLE_VALUE(bRc);
      }


      winHandleClose(p->hSharedShm);


      if( deleteFlag ){
        SimulateIOErrorBenign(1);
        sqlite3BeginBenignMalloc();
        winDelete(pVfs, p->zFilename, 0);
        sqlite3EndBenignMalloc();
        SimulateIOErrorBenign(0);
      }
      *pp = p->pNext;
      sqlite3_free(p->aRegion);
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
    }
  }
}

/*
** The DMS lock has not yet been taken on the shm file associated with
** pShmNode. Take the lock. Truncate the *-shm file if required.
** Return SQLITE_OK if successful, or an SQLite error code otherwise.





*/
static int winLockSharedMemory(winShmNode *pShmNode, DWORD nMs){
  HANDLE h = pShmNode->hSharedShm;
  int rc = SQLITE_OK;

  assert( sqlite3_mutex_held(pShmNode->mutex) );
  rc = winHandleLockTimeout(h, WIN_SHM_DMS, 1, 1, 0);
  if( rc==SQLITE_OK ){
    /* We have an EXCLUSIVE lock on the DMS byte. This means that this
    ** is the first process to open the file. Truncate it to zero bytes
    ** in this case.  */
    if( pShmNode->isReadonly ){
      rc = SQLITE_READONLY_CANTINIT;
    }else{
      rc = winHandleTruncate(h, 0);
    }

    /* Release the EXCLUSIVE lock acquired above. */
    winUnlockFile(&h, WIN_SHM_DMS, 0, 1, 0);
  }else if( (rc & 0xFF)==SQLITE_BUSY ){
    rc = SQLITE_OK;
  }

  if( rc==SQLITE_OK ){
    /* Take a SHARED lock on the DMS byte. */
    rc = winHandleLockTimeout(h, WIN_SHM_DMS, 1, 0, nMs);
    if( rc==SQLITE_OK ){
      pShmNode->isUnlocked = 0;
    }
  }

  return rc;
}


/*
** Convert a UTF-8 filename into whatever form the underlying
** operating system wants filenames in.  Space to hold the result
** is obtained from malloc and must be freed by the calling
** function
**
** On Cygwin, 3 possible input forms are accepted:
** - If the filename starts with "<drive>:/" or "<drive>:\",
**   it is converted to UTF-16 as-is.
** - If the filename contains '/', it is assumed to be a
**   Cygwin absolute path, it is converted to a win32
**   absolute path in UTF-16.
** - Otherwise it must be a filename only, the win32 filename
**   is returned in UTF-16.
** Note: If the function cygwin_conv_path() fails, only
**   UTF-8 -> UTF-16 conversion will be done. This can only
**   happen when the file path >32k, in which case winUtf8ToUnicode()
**   will fail too.
*/
static void *winConvertFromUtf8Filename(const char *zFilename){
  void *zConverted = 0;
  if( osIsNT() ){
#ifdef __CYGWIN__
    int nChar;
    LPWSTR zWideFilename;

    if( osCygwin_conv_path && !(winIsDriveLetterAndColon(zFilename)
        && winIsDirSep(zFilename[2])) ){
      int nByte;
      int convertflag = CCP_POSIX_TO_WIN_W;
      if( !strchr(zFilename, '/') ) convertflag |= CCP_RELATIVE;
      nByte = (int)osCygwin_conv_path(convertflag,
          zFilename, 0, 0);
      if( nByte>0 ){
        zConverted = sqlite3MallocZero(nByte+12);
        if ( zConverted==0 ){
          return zConverted;
        }
        zWideFilename = zConverted;
        /* Filenames should be prefixed, except when converted
         * full path already starts with "\\?\". */
        if( osCygwin_conv_path(convertflag, zFilename,
                             zWideFilename+4, nByte)==0 ){
          if( (convertflag&CCP_RELATIVE) ){
            memmove(zWideFilename, zWideFilename+4, nByte);
          }else if( memcmp(zWideFilename+4, L"\\\\", 4) ){
            memcpy(zWideFilename, L"\\\\?\\", 8);
          }else if( zWideFilename[6]!='?' ){
            memmove(zWideFilename+6, zWideFilename+4, nByte);
            memcpy(zWideFilename, L"\\\\?\\UNC", 14);
          }else{
            memmove(zWideFilename, zWideFilename+4, nByte);
          }
          return zConverted;
        }
        sqlite3_free(zConverted);
      }
    }
    nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
    if( nChar==0 ){
      return 0;
    }
    zWideFilename = sqlite3MallocZero( nChar*sizeof(WCHAR)+12 );
    if( zWideFilename==0 ){
      return 0;
    }
    nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1,
                                  zWideFilename, nChar);
    if( nChar==0 ){
      sqlite3_free(zWideFilename);
      zWideFilename = 0;
    }else if( nChar>MAX_PATH
        && winIsDriveLetterAndColon(zFilename)
        && winIsDirSep(zFilename[2]) ){
      memmove(zWideFilename+4, zWideFilename, nChar*sizeof(WCHAR));
      zWideFilename[2] = '\\';
      memcpy(zWideFilename, L"\\\\?\\", 8);
    }else if( nChar>MAX_PATH
        && winIsDirSep(zFilename[0]) && winIsDirSep(zFilename[1])
        && zFilename[2] != '?' ){
      memmove(zWideFilename+6, zWideFilename, nChar*sizeof(WCHAR));
      memcpy(zWideFilename, L"\\\\?\\UNC", 14);
    }
    zConverted = zWideFilename;
#else
    zConverted = winUtf8ToUnicode(zFilename);
#endif /* __CYGWIN__ */
  }
#if defined(SQLITE_WIN32_HAS_ANSI) && defined(_WIN32)
  else{
    zConverted = winUtf8ToMbcs(zFilename, osAreFileApisANSI());
  }
#endif
  /* caller will handle out of memory */
  return zConverted;
}

/*
** This function is used to open a handle on a *-shm file.
**
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined at build time, then the file
** is opened with FILE_FLAG_OVERLAPPED specified. If not, it is not.
*/
static int winHandleOpen(
  const char *zUtf8,              /* File to open */
  int *pbReadonly,                /* IN/OUT: True for readonly handle */
  HANDLE *ph                      /* OUT: New HANDLE for file */
){
  int rc = SQLITE_OK;
  void *zConverted = 0;
  int bReadonly = *pbReadonly;
  HANDLE h = INVALID_HANDLE_VALUE;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  const DWORD flag_overlapped = FILE_FLAG_OVERLAPPED;
#else
  const DWORD flag_overlapped = 0;
#endif

  /* Convert the filename to the system encoding. */
  zConverted = winConvertFromUtf8Filename(zUtf8);
  if( zConverted==0 ){
    OSTRACE(("OPEN name=%s, rc=SQLITE_IOERR_NOMEM", zUtf8));
    rc = SQLITE_IOERR_NOMEM_BKPT;
    goto winopenfile_out;
  }

  /* Ensure the file we are trying to open is not actually a directory. */
  if( winIsDir(zConverted) ){
    OSTRACE(("OPEN name=%s, rc=SQLITE_CANTOPEN_ISDIR", zUtf8));
    rc = SQLITE_CANTOPEN_ISDIR;
    goto winopenfile_out;
  }

  /* TODO: platforms.
  ** TODO: retry-on-ioerr.
  */
  if( osIsNT() ){
#if SQLITE_OS_WINRT
    CREATEFILE2_EXTENDED_PARAMETERS extendedParameters;
    memset(&extendedParameters, 0, sizeof(extendedParameters));
    extendedParameters.dwSize = sizeof(extendedParameters);
    extendedParameters.dwFileAttributes = FILE_ATTRIBUTE_NORMAL;
    extendedParameters.dwFileFlags = flag_overlapped;
    extendedParameters.dwSecurityQosFlags = SECURITY_ANONYMOUS;
    h = osCreateFile2((LPCWSTR)zConverted,
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),/* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,      /* dwShareMode */
        OPEN_ALWAYS,                             /* dwCreationDisposition */
        &extendedParameters
    );
#else
    h = osCreateFileW((LPCWSTR)zConverted,         /* lpFileName */
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),  /* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,        /* dwShareMode */
        NULL,                                      /* lpSecurityAttributes */
        OPEN_ALWAYS,                               /* dwCreationDisposition */
        FILE_ATTRIBUTE_NORMAL|flag_overlapped,
        NULL
    );
#endif
  }else{
    /* Due to pre-processor directives earlier in this file,
    ** SQLITE_WIN32_HAS_ANSI is always defined if osIsNT() is false. */
#ifdef SQLITE_WIN32_HAS_ANSI
    h = osCreateFileA((LPCSTR)zConverted,
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),  /* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,        /* dwShareMode */
        NULL,                                      /* lpSecurityAttributes */
        OPEN_ALWAYS,                               /* dwCreationDisposition */
        FILE_ATTRIBUTE_NORMAL|flag_overlapped,
        NULL
    );
#endif
  }

  if( h==INVALID_HANDLE_VALUE ){
    if( bReadonly==0 ){
      bReadonly = 1;
      rc = winHandleOpen(zUtf8, &bReadonly, &h);
    }else{
      rc = SQLITE_CANTOPEN_BKPT;
    }
  }

 winopenfile_out:
  sqlite3_free(zConverted);
  *pbReadonly = bReadonly;
  *ph = h;
  return rc;
}


/*
** Open the shared-memory area associated with database file pDbFd.




*/
static int winOpenSharedMemory(winFile *pDbFd){
  struct winShm *p;                  /* The connection to be opened */
  winShmNode *pShmNode = 0;          /* The underlying mmapped file */
  int rc = SQLITE_OK;                /* Result code */
  winShmNode *pNew;                  /* Newly allocated winShmNode */
  int nName;                         /* Size of zName in bytes */

  assert( pDbFd->pShm==0 );    /* Not previously opened */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.  */

  p = sqlite3MallocZero( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM_BKPT;
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3MallocZero( sizeof(*pShmNode) + (i64)nName + 17 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM_BKPT;
  }
  pNew->zFilename = (char*)&pNew[1];
  pNew->hSharedShm = INVALID_HANDLE_VALUE;
  pNew->isUnlocked = 1;
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename);

  /* Open a file-handle on the *-shm file for this connection. This file-handle
  ** is only used for locking. The mapping of the *-shm file is created using
  ** the shared file handle in winShmNode.hSharedShm.  */
  p->bReadonly = sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0);
  rc = winHandleOpen(pNew->zFilename, &p->bReadonly, &p->hShm);

  /* Look to see if there is an existing winShmNode that can be used.
  ** If no matching winShmNode currently exists, then create a new one.  */

  winShmEnterMutex();
  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
    /* TBD need to come up with better match here.  Perhaps
    ** use FILE_ID_BOTH_DIR_INFO Structure.  */

    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
  }
  if( pShmNode==0 ){





    pShmNode = pNew;





    /* Allocate a mutex for this winShmNode object, if one is required. */
    if( sqlite3GlobalConfig.bCoreMutex ){
      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
      if( pShmNode->mutex==0 ) rc = SQLITE_IOERR_NOMEM_BKPT;


    }

    /* Open a file-handle to use for mappings, and for the DMS lock. */
    if( rc==SQLITE_OK ){
      HANDLE h = INVALID_HANDLE_VALUE;
      pShmNode->isReadonly = p->bReadonly;
      rc = winHandleOpen(pNew->zFilename, &pShmNode->isReadonly, &h);
      pShmNode->hSharedShm = h;
    }

    /* If successful, link the new winShmNode into the global list. If an
    ** error occurred, free the object. */
    if( rc==SQLITE_OK ){
      pShmNode->pNext = winShmNodeList;
      winShmNodeList = pShmNode;
      pNew = 0;
    }else{


      sqlite3_mutex_free(pShmNode->mutex);
      if( pShmNode->hSharedShm!=INVALID_HANDLE_VALUE ){



        osCloseHandle(pShmNode->hSharedShm);

      }

    }


  }

  /* If no error has occurred, link the winShm object to the winShmNode and
  ** the winShm to pDbFd.  */
  if( rc==SQLITE_OK ){
    p->pShmNode = pShmNode;
    pShmNode->nRef++;
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
    p->id = pShmNode->nextShmId++;
#endif

    pDbFd->pShm = p;
  }else if( p ){
    winHandleClose(p->hShm);
    sqlite3_free(p);
  }















  assert( rc!=SQLITE_OK || pShmNode->isUnlocked==0 || pShmNode->nRegion==0 );
  winShmLeaveMutex();

  sqlite3_free(pNew);

  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying
** storage if deleteFlag is true.
*/
static int winShmUnmap(
  sqlite3_file *fd,          /* Database holding shared memory */
  int deleteFlag             /* Delete after closing if true */
){
  winFile *pDbFd;       /* Database holding shared-memory */
  winShm *p;            /* The connection to be closed */
  winShmNode *pShmNode; /* The underlying shared-memory file */


  pDbFd = (winFile*)fd;
  p = pDbFd->pShm;
  if( p==0 ) return SQLITE_OK;
  if( p->hShm!=INVALID_HANDLE_VALUE ){
    osCloseHandle(p->hShm);
  }








  pShmNode = p->pShmNode;
  winShmEnterMutex();

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too. */

  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    winShmPurge(pDbFd->pVfs, deleteFlag);
  }
  winShmLeaveMutex();

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  return SQLITE_OK;
}

/*
** Change the lock state for a shared-memory segment.
*/
static int winShmLock(
  sqlite3_file *fd,          /* Database file holding the shared memory */
  int ofst,                  /* First lock to acquire or release */
  int n,                     /* Number of locks to acquire or release */
  int flags                  /* What to do with the lock */
){
  winFile *pDbFd = (winFile*)fd;        /* Connection holding shared memory */
  winShm *p = pDbFd->pShm;              /* The shared memory being locked */

  winShmNode *pShmNode;
  int rc = SQLITE_OK;                   /* Result code */
  u16 mask = (u16)((1U<<(ofst+n)) - (1U<<ofst)); /* Mask of locks to [un]take */

  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
  pShmNode = p->pShmNode;
  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;

  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
  assert( n>=1 );
  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );

  /* Check that, if this to be a blocking lock, no locks that occur later
  ** in the following list than the lock being obtained are already held:
  **
  **   1. Checkpointer lock (ofst==1).
  **   2. Write lock (ofst==0).

  **   3. Read locks (ofst>=3 && ofst<SQLITE_SHM_NLOCK).
  **
  ** In other words, if this is a blocking lock, none of the locks that
  ** occur later in the above list than the lock being obtained may be
  ** held.
  **
  ** It is not permitted to block on the RECOVER lock.
  */
#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && defined(SQLITE_DEBUG)
  {



    u16 lockMask = (p->exclMask|p->sharedMask);


    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
          (ofst!=2)                                   /* not RECOVER */
       && (ofst!=1 || lockMask==0 || lockMask==2)
       && (ofst!=0 || lockMask<3)




       && (ofst<3  || lockMask<(1<<ofst))
    ));
  }

#endif





  /* Check if there is any work to do. There are three cases:
  **
  **    a) An unlock operation where there are locks to unlock,
  **    b) An shared lock where the requested lock is not already held
  **    c) An exclusive lock where the requested lock is not already held

  **
  ** The SQLite core never requests an exclusive lock that it already holds.
  ** This is assert()ed immediately below.  */
  assert( flags!=(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK)
       || 0==(p->exclMask & mask)
  );
  if( ((flags & SQLITE_SHM_UNLOCK) && ((p->exclMask|p->sharedMask) & mask))


   || (flags==(SQLITE_SHM_SHARED|SQLITE_SHM_LOCK) && 0==(p->sharedMask & mask))

   || (flags==(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK))
  ){


    if( flags & SQLITE_SHM_UNLOCK ){


      /* Case (a) - unlock.  */


      assert( (p->exclMask & p->sharedMask)==0 );
      assert( !(flags & SQLITE_SHM_EXCLUSIVE) || (p->exclMask & mask)==mask );
      assert( !(flags & SQLITE_SHM_SHARED) || (p->sharedMask & mask)==mask );

      rc = winHandleUnlock(p->hShm, ofst+WIN_SHM_BASE, n);

      /* If successful, also clear the bits in sharedMask/exclMask */
      if( rc==SQLITE_OK ){
        p->exclMask = (p->exclMask & ~mask);
        p->sharedMask = (p->sharedMask & ~mask);
      }
    }else{

      int bExcl = ((flags & SQLITE_SHM_EXCLUSIVE) ? 1 : 0);

      DWORD nMs = winFileBusyTimeout(pDbFd);
      rc = winHandleLockTimeout(p->hShm, ofst+WIN_SHM_BASE, n, bExcl, nMs);

      if( rc==SQLITE_OK ){
        if( bExcl ){
          p->exclMask = (p->exclMask | mask);
        }else{
          p->sharedMask = (p->sharedMask | mask);
        }
      }








    }
  }


  OSTRACE((
      "SHM-LOCK(%d,%d,%d) pid=%lu, id=%d, sharedMask=%03x, exclMask=%03x,"
      " rc=%s\n",
      ofst, n, flags,
      osGetCurrentProcessId(), p->id, p->sharedMask, p->exclMask,
      sqlite3ErrName(rc))
  );
  return rc;
}

/*
** Implement a memory barrier or memory fence on shared memory.
**
** All loads and stores begun before the barrier must complete before

    pShm = pDbFd->pShm;
    assert( pShm!=0 );
  }
  pShmNode = pShm->pShmNode;

  sqlite3_mutex_enter(pShmNode->mutex);
  if( pShmNode->isUnlocked ){
    /* Take the DMS lock. */
    assert( pShmNode->nRegion==0 );
    rc = winLockSharedMemory(pShmNode, winFileBusyTimeout(pDbFd));
    if( rc!=SQLITE_OK ) goto shmpage_out;

  }


  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
  if( pShmNode->nRegion<=iRegion ){
    HANDLE hShared = pShmNode->hSharedShm;
    struct ShmRegion *apNew;           /* New aRegion[] array */
    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
    sqlite3_int64 sz;                  /* Current size of wal-index file */

    pShmNode->szRegion = szRegion;

    /* The requested region is not mapped into this processes address space.
    ** Check to see if it has been allocated (i.e. if the wal-index file is
    ** large enough to contain the requested region).
    */
    rc = winHandleSize(hShared, &sz);
    if( rc!=SQLITE_OK ){

      rc = winLogError(rc, osGetLastError(), "winShmMap1", pDbFd->zPath);
      goto shmpage_out;
    }

    if( sz<nByte ){
      /* The requested memory region does not exist. If isWrite is set to
      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
      **
      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
      ** the requested memory region.  */

      if( !isWrite ) goto shmpage_out;
      rc = winHandleTruncate(hShared, nByte);
      if( rc!=SQLITE_OK ){

        rc = winLogError(rc, osGetLastError(), "winShmMap2", pDbFd->zPath);
        goto shmpage_out;
      }
    }

    /* Map the requested memory region into this processes address space. */
    apNew = (struct ShmRegion*)sqlite3_realloc64(
        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
    );
    if( !apNew ){
      rc = SQLITE_IOERR_NOMEM_BKPT;
      goto shmpage_out;
    }
    pShmNode->aRegion = apNew;

    if( pShmNode->isReadonly ){
      protect = PAGE_READONLY;
      flags = FILE_MAP_READ;
    }

    while( pShmNode->nRegion<=iRegion ){
      HANDLE hMap = NULL;         /* file-mapping handle */
      void *pMap = 0;             /* Mapped memory region */

#if SQLITE_OS_WINRT
      hMap = osCreateFileMappingFromApp(hShared, NULL, protect, nByte, NULL);


#elif defined(SQLITE_WIN32_HAS_WIDE)
      hMap = osCreateFileMappingW(hShared, NULL, protect, 0, nByte, NULL);


#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
      hMap = osCreateFileMappingA(hShared, NULL, protect, 0, nByte, NULL);


#endif

      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%d, rc=%s\n",
               osGetCurrentProcessId(), pShmNode->nRegion, nByte,
               hMap ? "ok" : "failed"));
      if( hMap ){
        int iOffset = pShmNode->nRegion*szRegion;
        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
#if SQLITE_OS_WINRT

    int iOffset = iRegion*szRegion;
    int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
    char *p = (char *)pShmNode->aRegion[iRegion].pMap;
    *pp = (void *)&p[iOffsetShift];
  }else{
    *pp = 0;
  }
  if( pShmNode->isReadonly && rc==SQLITE_OK ){
    rc = SQLITE_READONLY;
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  return rc;
}

#else
# define winShmMap     0
# define winShmLock    0

/****************************************************************************
**************************** sqlite3_vfs methods ****************************
**
** This division contains the implementation of methods on the
** sqlite3_vfs object.
*/

#if 0 /* No longer necessary */
/*
** Convert a filename from whatever the underlying operating system
** supports for filenames into UTF-8.  Space to hold the result is
** obtained from malloc and must be freed by the calling function.
*/
static char *winConvertToUtf8Filename(const void *zFilename){
  char *zConverted = 0;
  if( osIsNT() ){
    zConverted = winUnicodeToUtf8(zFilename);
  }
#ifdef SQLITE_WIN32_HAS_ANSI
  else{
    zConverted = winMbcsToUtf8(zFilename, osAreFileApisANSI());
  }
#endif
  /* caller will handle out of memory */
  return zConverted;
}
#endif





















/*
** This function returns non-zero if the specified UTF-8 string buffer
** ends with a directory separator character or one was successfully
** added to it.
*/
static int winMakeEndInDirSep(int nBuf, char *zBuf){
  if( zBuf ){
    int nLen = sqlite3Strlen30(zBuf);
    if( nLen>0 ){
      if( winIsDirSep(zBuf[nLen-1]) ){
        return 1;
      }else if( nLen+1<nBuf ){
        if( !osGetenv ){
          zBuf[nLen] = winGetDirSep();
        }else if( winIsDriveLetterAndColon(zBuf) && winIsDirSep(zBuf[2]) ){
          zBuf[nLen] = '\\';
          zBuf[2]='\\';
        }else{
          zBuf[nLen] = '/';
        }
        zBuf[nLen+1] = '\0';
        return 1;
      }
    }
  }
  return 0;
}

}

/*
** Create a temporary file name and store the resulting pointer into pzBuf.
** The pointer returned in pzBuf must be freed via sqlite3_free().
*/
static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
  static const char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  size_t i, j;
  DWORD pid;
  int nPre = sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX);
  i64 nMax, nBuf, nDir, nLen;

      }
      sqlite3_snprintf(nMax, zBuf, "%s", sqlite3_temp_directory);
    }
    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
  }

#if defined(__CYGWIN__)
  else if( osGetenv!=NULL ){
    static const char *azDirs[] = {
       0, /* getenv("SQLITE_TMPDIR") */
       0, /* getenv("TMPDIR") */
       0, /* getenv("TMP") */
       0, /* getenv("TEMP") */
       0, /* getenv("USERPROFILE") */
       "/var/tmp",
       "/usr/tmp",
       "/tmp",
       ".",
       0        /* List terminator */
    };
    unsigned int i;
    const char *zDir = 0;

    if( !azDirs[0] ) azDirs[0] = osGetenv("SQLITE_TMPDIR");
    if( !azDirs[1] ) azDirs[1] = osGetenv("TMPDIR");
    if( !azDirs[2] ) azDirs[2] = osGetenv("TMP");
    if( !azDirs[3] ) azDirs[3] = osGetenv("TEMP");
    if( !azDirs[4] ) azDirs[4] = osGetenv("USERPROFILE");
    for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
      void *zConverted;
      if( zDir==0 ) continue;
      /* If the path starts with a drive letter followed by the colon
      ** character, assume it is already a native Win32 path; otherwise,
      ** it must be converted to a native Win32 path via the Cygwin API
      ** prior to using it.
      */

      {
        zConverted = winConvertFromUtf8Filename(zDir);
        if( !zConverted ){
          sqlite3_free(zBuf);
          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
          return SQLITE_IOERR_NOMEM_BKPT;
        }
        if( winIsDir(zConverted) ){
          sqlite3_snprintf(nMax, zBuf, "%s", zDir);
          sqlite3_free(zConverted);
          break;
        }
        sqlite3_free(zConverted);
#if 0 /* No longer necessary */
      }else{
        zConverted = sqlite3MallocZero( nMax+1 );
        if( !zConverted ){
          sqlite3_free(zBuf);
          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
          return SQLITE_IOERR_NOMEM_BKPT;
        }
        if( osCygwin_conv_path(
                CCP_POSIX_TO_WIN_W, zDir,
                zConverted, nMax+1)<0 ){
          sqlite3_free(zConverted);
          sqlite3_free(zBuf);
          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_CONVPATH\n"));
          return winLogError(SQLITE_IOERR_CONVPATH, (DWORD)errno,
                             "winGetTempname2", zDir);
        }

          }
          sqlite3_snprintf(nMax, zBuf, "%s", zUtf8);
          sqlite3_free(zUtf8);
          sqlite3_free(zConverted);
          break;
        }
        sqlite3_free(zConverted);
#endif /* No longer necessary */
      }
    }
  }
#endif

#if !SQLITE_OS_WINRT && defined(_WIN32)
  else if( osIsNT() ){
    char *zMulti;
    LPWSTR zWidePath = sqlite3MallocZero( nMax*sizeof(WCHAR) );
    if( !zWidePath ){
      sqlite3_free(zBuf);
      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
      return SQLITE_IOERR_NOMEM_BKPT;

    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
                             GetFileExInfoStandard,
                             &sAttrData)) && winRetryIoerr(&cnt, &lastErrno) ){}
    if( !rc ){
      return 0; /* Invalid name? */
    }
    attr = sAttrData.dwFileAttributes;
#if SQLITE_OS_WINCE==0 && defined(SQLITE_WIN32_HAS_ANSI)
  }else{
    attr = osGetFileAttributesA((char*)zConverted);
#endif
  }
  return (attr!=INVALID_FILE_ATTRIBUTES) && (attr&FILE_ATTRIBUTE_DIRECTORY);
}

/* forward reference */
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
);

/*
** The Windows version of xAccess() accepts an extra bit in the flags
** parameter that prevents an anti-virus retry loop.
*/
#define NORETRY 0x4000

/*
** Open a file.
*/
static int winOpen(
  sqlite3_vfs *pVfs,        /* Used to get maximum path length and AppData */
  const char *zName,        /* Name of the file (UTF-8) */
  sqlite3_file *id,         /* Write the SQLite file handle here */

  int isTemp = 0;
#endif
  winVfsAppData *pAppData;
  winFile *pFile = (winFile*)id;
  void *zConverted;              /* Filename in OS encoding */
  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
  int cnt = 0;
  int isRO = 0;              /* file is known to be accessible readonly */

  /* If argument zPath is a NULL pointer, this function is required to open
  ** a temporary file. Use this buffer to store the file name in.
  */
  char *zTmpname = 0; /* For temporary filename, if necessary. */

  int rc = SQLITE_OK;            /* Function Return Code */

      h = osCreateFile2((LPCWSTR)zConverted,
                        dwDesiredAccess,
                        dwShareMode,
                        dwCreationDisposition,
                        &extendedParameters);
      if( h!=INVALID_HANDLE_VALUE ) break;
      if( isReadWrite ){
        int rc2;
        sqlite3BeginBenignMalloc();
        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ|NORETRY, &isRO);
        sqlite3EndBenignMalloc();
        if( rc2==SQLITE_OK && isRO ) break;
      }
    }while( winRetryIoerr(&cnt, &lastErrno) );
#else
    do{
      h = osCreateFileW((LPCWSTR)zConverted,
                        dwDesiredAccess,
                        dwShareMode, NULL,
                        dwCreationDisposition,
                        dwFlagsAndAttributes,
                        NULL);
      if( h!=INVALID_HANDLE_VALUE ) break;
      if( isReadWrite ){
        int rc2;
        sqlite3BeginBenignMalloc();
        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ|NORETRY, &isRO);
        sqlite3EndBenignMalloc();
        if( rc2==SQLITE_OK && isRO ) break;
      }
    }while( winRetryIoerr(&cnt, &lastErrno) );
#endif
  }
#ifdef SQLITE_WIN32_HAS_ANSI
  else{
    do{
      h = osCreateFileA((LPCSTR)zConverted,
                        dwDesiredAccess,
                        dwShareMode, NULL,
                        dwCreationDisposition,
                        dwFlagsAndAttributes,
                        NULL);
      if( h!=INVALID_HANDLE_VALUE ) break;
      if( isReadWrite ){
        int rc2;
        sqlite3BeginBenignMalloc();
        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ|NORETRY, &isRO);
        sqlite3EndBenignMalloc();
        if( rc2==SQLITE_OK && isRO ) break;
      }
    }while( winRetryIoerr(&cnt, &lastErrno) );
  }
#endif
  winLogIoerr(cnt, __LINE__);

  OSTRACE(("OPEN file=%p, name=%s, access=%lx, rc=%s\n", h, zUtf8Name,
           dwDesiredAccess, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));

  if( h==INVALID_HANDLE_VALUE ){
    sqlite3_free(zConverted);
    sqlite3_free(zTmpname);
    if( isReadWrite && isRO && !isExclusive ){
      return winOpen(pVfs, zName, id,
         ((flags|SQLITE_OPEN_READONLY) &
                     ~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)),
         pOutFlags);
    }else{
      pFile->lastErrno = lastErrno;
      winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);

  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){
  DWORD attr;
  int rc = 0;
  DWORD lastErrno = 0;
  void *zConverted;
  int noRetry = 0;           /* Do not use winRetryIoerr() */
  UNUSED_PARAMETER(pVfs);

  if( (flags & NORETRY)!=0 ){
    noRetry = 1;
    flags &= ~NORETRY;
  }

  SimulateIOError( return SQLITE_IOERR_ACCESS; );
  OSTRACE(("ACCESS name=%s, flags=%x, pResOut=%p\n",
           zFilename, flags, pResOut));

  if( zFilename==0 ){
    *pResOut = 0;

  }
  if( osIsNT() ){
    int cnt = 0;
    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
    memset(&sAttrData, 0, sizeof(sAttrData));
    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
                             GetFileExInfoStandard,
                             &sAttrData))
       && !noRetry
       && winRetryIoerr(&cnt, &lastErrno)
    ){ /* Loop until true */}
    if( rc ){
      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
      ** as if it does not exist.
      */
      if(    flags==SQLITE_ACCESS_EXISTS
          && sAttrData.nFileSizeHigh==0
          && sAttrData.nFileSizeLow==0 ){

*/
static BOOL winIsDriveLetterAndColon(
  const char *zPathname
){
  return ( sqlite3Isalpha(zPathname[0]) && zPathname[1]==':' );
}

#ifdef _WIN32
/*
** Returns non-zero if the specified path name should be used verbatim.  If
** non-zero is returned from this function, the calling function must simply
** use the provided path name verbatim -OR- resolve it into a full path name
** using the GetFullPathName Win32 API function (if available).
*/
static BOOL winIsVerbatimPathname(

  /*
  ** If we get to this point, the path name should almost certainly be a purely
  ** relative one (i.e. not a UNC name, not absolute, and not volume relative).
  */
  return FALSE;
}
#endif /* _WIN32 */

#ifdef __CYGWIN__
/*
** Simplify a filename into its canonical form
** by making the following changes:
**
**  * convert any '/' to '\' (win32) or reverse (Cygwin)
**  * removing any trailing and duplicate / (except for UNC paths)
**  * convert /./ into just /
**
** Changes are made in-place.  Return the new name length.
**
** The original filename is in z[0..]. If the path is shortened,
** no-longer used bytes will be written by '\0'.
*/
static void winSimplifyName(char *z){
  int i, j;
  for(i=j=0; z[i]; ++i){
    if( winIsDirSep(z[i]) ){
#if !defined(SQLITE_TEST)
      /* Some test-cases assume that "./foo" and "foo" are different */
      if( z[i+1]=='.' && winIsDirSep(z[i+2]) ){
        ++i;
        continue;
      }
#endif
      if( !z[i+1] || (winIsDirSep(z[i+1]) && (i!=0)) ){
        continue;
      }
      z[j++] = osGetenv?'/':'\\';
    }else{
      z[j++] = z[i];
    }
  }
  while(j<i) z[j++] = '\0';
}

#define SQLITE_MAX_SYMLINKS 100

static int mkFullPathname(
  const char *zPath,              /* Input path */
  char *zOut,                     /* Output buffer */
  int nOut                        /* Allocated size of buffer zOut */
){
  int nPath = sqlite3Strlen30(zPath);
  int iOff = 0;
  if( zPath[0]!='/' ){
    if( osGetcwd(zOut, nOut-2)==0 ){
      return winLogError(SQLITE_CANTOPEN_BKPT, (DWORD)osErrno, "getcwd", zPath);
    }
    iOff = sqlite3Strlen30(zOut);
    zOut[iOff++] = '/';
  }
  if( (iOff+nPath+1)>nOut ){
    /* SQLite assumes that xFullPathname() nul-terminates the output buffer
    ** even if it returns an error.  */
    zOut[iOff] = '\0';
    return SQLITE_CANTOPEN_BKPT;
  }
  sqlite3_snprintf(nOut-iOff, &zOut[iOff], "%s", zPath);
  return SQLITE_OK;
}
#endif /* __CYGWIN__ */

/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
** bytes in size.
*/
static int winFullPathnameNoMutex(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zRelative,        /* Possibly relative input path */
  int nFull,                    /* Size of output buffer in bytes */
  char *zFull                   /* Output buffer */
){
#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
  int nByte;
  void *zConverted;
  char *zOut;
#endif

  /* If this path name begins with "/X:" or "\\?\", where "X" is any
  ** alphabetic character, discard the initial "/" from the pathname.
  */
  if( zRelative[0]=='/' && (winIsDriveLetterAndColon(zRelative+1)
       || winIsLongPathPrefix(zRelative+1)) ){
    zRelative++;
  }

  SimulateIOError( return SQLITE_ERROR );

#ifdef __CYGWIN__
  if( osGetcwd ){
    zFull[nFull-1] = '\0';
    if( !winIsDriveLetterAndColon(zRelative) || !winIsDirSep(zRelative[2]) ){
      int rc = SQLITE_OK;
      int nLink = 1;                /* Number of symbolic links followed so far */
      const char *zIn = zRelative;      /* Input path for each iteration of loop */
      char *zDel = 0;
      struct stat buf;

      UNUSED_PARAMETER(pVfs);

      do {
        /* Call lstat() on path zIn. Set bLink to true if the path is a symbolic
        ** link, or false otherwise.  */
        int bLink = 0;
        if( osLstat && osReadlink ) {
          if( osLstat(zIn, &buf)!=0 ){
            int myErrno = osErrno;
            if( myErrno!=ENOENT ){
              rc = winLogError(SQLITE_CANTOPEN_BKPT, (DWORD)myErrno, "lstat", zIn);
            }
          }else{
            bLink = ((buf.st_mode & 0170000) == 0120000);
          }

          if( bLink ){
            if( zDel==0 ){
              zDel = sqlite3MallocZero(nFull);
              if( zDel==0 ) rc = SQLITE_NOMEM;
            }else if( ++nLink>SQLITE_MAX_SYMLINKS ){
              rc = SQLITE_CANTOPEN_BKPT;
            }

            if( rc==SQLITE_OK ){
              nByte = osReadlink(zIn, zDel, nFull-1);
              if( nByte ==(DWORD)-1 ){
                rc = winLogError(SQLITE_CANTOPEN_BKPT, (DWORD)osErrno, "readlink", zIn);
              }else{
                if( zDel[0]!='/' ){
                  int n;
                  for(n = sqlite3Strlen30(zIn); n>0 && zIn[n-1]!='/'; n--);
                  if( nByte+n+1>nFull ){
                    rc = SQLITE_CANTOPEN_BKPT;
                  }else{
                    memmove(&zDel[n], zDel, nByte+1);
                    memcpy(zDel, zIn, n);
                    nByte += n;
                  }
                }
                zDel[nByte] = '\0';
              }
            }

            zIn = zDel;
          }
        }

        assert( rc!=SQLITE_OK || zIn!=zFull || zIn[0]=='/' );
        if( rc==SQLITE_OK && zIn!=zFull ){
          rc = mkFullPathname(zIn, zFull, nFull);
        }
        if( bLink==0 ) break;
        zIn = zFull;
      }while( rc==SQLITE_OK );

      sqlite3_free(zDel);
      winSimplifyName(zFull);
      return rc;
    }
  }
#endif /* __CYGWIN__ */
#if 0 /* This doesn't work correctly at all! See:
  <https://marc.info/?l=sqlite-users&m=139299149416314&w=2>
*/
  SimulateIOError( return SQLITE_ERROR );
  UNUSED_PARAMETER(nFull);
  assert( nFull>=pVfs->mxPathname );





























  char *zOut = sqlite3MallocZero( pVfs->mxPathname+1 );
  if( !zOut ){
    return SQLITE_IOERR_NOMEM_BKPT;
  }
  if( osCygwin_conv_path(
          CCP_POSIX_TO_WIN_W,
          zRelative, zOut, pVfs->mxPathname+1)<0 ){
    sqlite3_free(zOut);
    return winLogError(SQLITE_CANTOPEN_CONVPATH, (DWORD)errno,
                       "winFullPathname2", zRelative);
  }else{
    char *zUtf8 = winConvertToUtf8Filename(zOut);
    if( !zUtf8 ){
      sqlite3_free(zOut);
      return SQLITE_IOERR_NOMEM_BKPT;
    }
    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zUtf8);
    sqlite3_free(zUtf8);
    sqlite3_free(zOut);
  }

  return SQLITE_OK;
#endif

#if (SQLITE_OS_WINCE || SQLITE_OS_WINRT) && defined(_WIN32)
  SimulateIOError( return SQLITE_ERROR );
  /* WinCE has no concept of a relative pathname, or so I am told. */
  /* WinRT has no way to convert a relative path to an absolute one. */
  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
    /*
    ** NOTE: We are dealing with a relative path name and the data
    **       directory has been set.  Therefore, use it as the basis
    **       for converting the relative path name to an absolute
    **       one by prepending the data directory and a backslash.
    */
    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
                     sqlite3_data_directory, winGetDirSep(), zRelative);
  }else{
    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zRelative);
  }
  return SQLITE_OK;
#endif

#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
#if defined(_WIN32)
  /* 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. This function could fail if, for example, the
  ** current working directory has been unlinked.
  */
  SimulateIOError( return SQLITE_ERROR );
  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
    /*
    ** NOTE: We are dealing with a relative path name and the data
    **       directory has been set.  Therefore, use it as the basis
    **       for converting the relative path name to an absolute
    **       one by prepending the data directory and a backslash.
    */
    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
                     sqlite3_data_directory, winGetDirSep(), zRelative);
    return SQLITE_OK;
  }
#endif
  zConverted = winConvertFromUtf8Filename(zRelative);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM_BKPT;
  }
  if( osIsNT() ){
    LPWSTR zTemp;
    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0);
    if( nByte==0 ){
      sqlite3_free(zConverted);
      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
                         "winFullPathname1", zRelative);
    }
    nByte += 3;
    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM_BKPT;
    }
    nByte = osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
    if( nByte==0 ){
      sqlite3_free(zConverted);
      sqlite3_free(zTemp);
      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
                         "winFullPathname2", zRelative);
    }
    sqlite3_free(zConverted);

    }
    sqlite3_free(zConverted);
    zOut = winMbcsToUtf8(zTemp, osAreFileApisANSI());
    sqlite3_free(zTemp);
  }
#endif
  if( zOut ){
#ifdef __CYGWIN__
    if( memcmp(zOut, "\\\\?\\", 4) ){
      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut);
    }else if( memcmp(zOut+4, "UNC\\", 4) ){
      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut+4);
    }else{
      char *p = zOut+6;
      *p = '\\';
      if( osGetcwd ){
        /* On Cygwin, UNC paths use forward slashes */
        while( *p ){
          if( *p=='\\' ) *p = '/';
          ++p;
        }
      }
      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut+6);
    }
#else
    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut);
#endif /* __CYGWIN__ */
    sqlite3_free(zOut);
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR_NOMEM_BKPT;
  }
#endif
}

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
  HANDLE h;
#if 0 /* This doesn't work correctly at all! See:
  <https://marc.info/?l=sqlite-users&m=139299149416314&w=2>
*/
  int nFull = pVfs->mxPathname+1;
  char *zFull = sqlite3MallocZero( nFull );
  void *zConverted = 0;
  if( zFull==0 ){
    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
    return 0;
  }

    winGetSystemCall,      /* xGetSystemCall */
    winNextSystemCall,     /* xNextSystemCall */
  };
#endif

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==89 );

  /* get memory map allocation granularity */
  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
#if SQLITE_OS_WINRT
  osGetNativeSystemInfo(&winSysInfo);
#else
  osGetSystemInfo(&winSysInfo);

#define BITVEC_MXHASH    (BITVEC_NINT/2)
/* Hashing function for the aHash representation.
** Empirical testing showed that the *37 multiplier
** (an arbitrary prime)in the hash function provided
** no fewer collisions than the no-op *1. */
#define BITVEC_HASH(X)   (((X)*1)%BITVEC_NINT)

#define BITVEC_NPTR      ((u32)(BITVEC_USIZE/sizeof(Bitvec *)))


/*
** A bitmap is an instance of the following structure.
**
** This bitmap records the existence of zero or more bits
** with values between 1 and iSize, inclusive.

    i = i%p->iDivisor;
    p = p->u.apSub[bin];
    if (!p) {
      return;
    }
  }
  if( p->iSize<=BITVEC_NBIT ){
    p->u.aBitmap[i/BITVEC_SZELEM] &= ~(BITVEC_TELEM)(1<<(i&(BITVEC_SZELEM-1)));
  }else{
    unsigned int j;
    u32 *aiValues = pBuf;
    memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
    memset(p->u.aHash, 0, sizeof(p->u.aHash));
    p->nSet = 0;
    for(j=0; j<BITVEC_NINT; j++){

/*
** Let V[] be an array of unsigned characters sufficient to hold
** up to N bits.  Let I be an integer between 0 and N.  0<=I<N.
** Then the following macros can be used to set, clear, or test
** individual bits within V.
*/
#define SETBIT(V,I)      V[I>>3] |= (1<<(I&7))
#define CLEARBIT(V,I)    V[I>>3] &= ~(BITVEC_TELEM)(1<<(I&7))
#define TESTBIT(V,I)     (V[I>>3]&(1<<(I&7)))!=0

/*
** This routine runs an extensive test of the Bitvec code.
**
** The input is an array of integers that acts as a program
** to test the Bitvec.  The integers are opcodes followed

  int nSlot;                     /* The number of pcache slots */
  int nReserve;                  /* Try to keep nFreeSlot above this */
  void *pStart, *pEnd;           /* Bounds of global page cache memory */
  /* Above requires no mutex.  Use mutex below for variable that follow. */
  sqlite3_mutex *mutex;          /* Mutex for accessing the following: */
  PgFreeslot *pFree;             /* Free page blocks */
  int nFreeSlot;                 /* Number of unused pcache slots */




  int bUnderPressure;            /* True if low on PAGECACHE memory */
} pcache1_g;

/*
** All code in this file should access the global structure above via the
** alias "pcache1". This ensures that the WSD emulation is used when
** compiling for systems that do not support real WSD.

    if( n==0 ) sz = 0;
    sz = ROUNDDOWN8(sz);
    pcache1.szSlot = sz;
    pcache1.nSlot = pcache1.nFreeSlot = n;
    pcache1.nReserve = n>90 ? 10 : (n/10 + 1);
    pcache1.pStart = pBuf;
    pcache1.pFree = 0;
    AtomicStore(&pcache1.bUnderPressure,0);
    while( n-- ){
      p = (PgFreeslot*)pBuf;
      p->pNext = pcache1.pFree;
      pcache1.pFree = p;
      pBuf = (void*)&((char*)pBuf)[sz];
    }
    pcache1.pEnd = pBuf;

  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
  if( nByte<=pcache1.szSlot ){
    sqlite3_mutex_enter(pcache1.mutex);
    p = (PgHdr1 *)pcache1.pFree;
    if( p ){
      pcache1.pFree = pcache1.pFree->pNext;
      pcache1.nFreeSlot--;
      AtomicStore(&pcache1.bUnderPressure,pcache1.nFreeSlot<pcache1.nReserve);
      assert( pcache1.nFreeSlot>=0 );
      sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
      sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_USED, 1);
    }
    sqlite3_mutex_leave(pcache1.mutex);
  }
  if( p==0 ){

    PgFreeslot *pSlot;
    sqlite3_mutex_enter(pcache1.mutex);
    sqlite3StatusDown(SQLITE_STATUS_PAGECACHE_USED, 1);
    pSlot = (PgFreeslot*)p;
    pSlot->pNext = pcache1.pFree;
    pcache1.pFree = pSlot;
    pcache1.nFreeSlot++;
    AtomicStore(&pcache1.bUnderPressure,pcache1.nFreeSlot<pcache1.nReserve);
    assert( pcache1.nFreeSlot<=pcache1.nSlot );
    sqlite3_mutex_leave(pcache1.mutex);
  }else{
    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
    {

** Or, the heap is used for all page cache memory but the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
    return AtomicLoad(&pcache1.bUnderPressure);
  }else{
    return sqlite3HeapNearlyFull();
  }
}

/******************************************************************************/
/******** General Implementation Functions ************************************/

  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  releaseAllSavepoints(pPager);

  if( pagerUseWal(pPager) ){
    assert( !isOpen(pPager->jfd) );
    if( pPager->eState==PAGER_ERROR ){
      /* If an IO error occurs in wal.c while attempting to wrap the wal file,
      ** then the Wal object may be holding a write-lock but no read-lock.
      ** This call ensures that the write-lock is dropped as well. We cannot
      ** have sqlite3WalEndReadTransaction() drop the write-lock, as it once
      ** did, because this would break "BEGIN EXCLUSIVE" handling for
      ** SQLITE_ENABLE_SETLK_TIMEOUT builds.  */
      sqlite3WalEndWriteTransaction(pPager->pWal);
    }
    sqlite3WalEndReadTransaction(pPager->pWal);
    pPager->eState = PAGER_OPEN;
  }else if( !pPager->exclusiveMode ){
    int rc;                       /* Error code returned by pagerUnlockDb() */
    int iDc = isOpen(pPager->fd)?sqlite3OsDeviceCharacteristics(pPager->fd):0;

    /* If the operating system support deletion of open files, then

#define walFrameOffset(iFrame, szPage) (                               \
  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
)

/*
** An open write-ahead log file is represented by an instance of the
** following object.
**
** writeLock:
**   This is usually set to 1 whenever the WRITER lock is held. However,
**   if it is set to 2, then the WRITER lock is held but must be released
**   by walHandleException() if a SEH exception is thrown.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */

  int nSegment;                   /* Number of entries in aSegment[] */
  struct WalSegment {
    int iNext;                    /* Next slot in aIndex[] not yet returned */
    ht_slot *aIndex;              /* i0, i1, i2... such that aPgno[iN] ascend */
    u32 *aPgno;                   /* Array of page numbers. */
    int nEntry;                   /* Nr. of entries in aPgno[] and aIndex[] */
    int iZero;                    /* Frame number associated with aPgno[0] */
  } aSegment[FLEXARRAY];          /* One for every 32KB page in the wal-index */
};

/* Size (in bytes) of a WalIterator object suitable for N or fewer segments */
#define SZ_WALITERATOR(N)  \
     (offsetof(WalIterator,aSegment)*(N)*sizeof(struct WalSegment))

/*
** Define the parameters of the hash tables in the wal-index file. There
** is a hash-table following every HASHTABLE_NPAGE page numbers in the
** wal-index.
**
** Changing any of these constants will alter the wal-index format and

  if( aIn ){
    s1 = aIn[0];
    s2 = aIn[1];
  }else{
    s1 = s2 = 0;
  }

  /* nByte is a multiple of 8 between 8 and 65536 */
  assert( nByte>=8 && (nByte&7)==0 && nByte<=65536 );




  if( !nativeCksum ){
    do {
      s1 += BYTESWAP32(aData[0]) + s2;
      s2 += BYTESWAP32(aData[1]) + s1;
      aData += 2;
    }while( aData<aEnd );

  ** it only runs if there is actually content in the log (mxFrame>0).
  */
  assert( pWal->ckptLock && pWal->hdr.mxFrame>0 );
  iLast = pWal->hdr.mxFrame;

  /* Allocate space for the WalIterator object. */
  nSegment = walFramePage(iLast) + 1;
  nByte = SZ_WALITERATOR(nSegment)

        + iLast*sizeof(ht_slot);
  p = (WalIterator *)sqlite3_malloc64(nByte
      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
  );
  if( !p ){
    return SQLITE_NOMEM_BKPT;
  }

** they are supported by the VFS, and (b) the database handle is configured
** with a busy-timeout. Return 1 if blocking locks are successfully enabled,
** or 0 otherwise.
*/
static int walEnableBlocking(Wal *pWal){
  int res = 0;
  if( pWal->db ){
    int tmout = pWal->db->setlkTimeout;
    if( tmout ){
      res = walEnableBlockingMs(pWal, tmout);
    }
  }
  return res;
}

**   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;
    if( pWal->writeLock==2 ) pWal->writeLock = 0;
    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);

        rc = SQLITE_READONLY_RECOVERY;
      }
    }else{
      int bWriteLock = pWal->writeLock;
      if( bWriteLock
       || SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1))
      ){
        /* If the write-lock was just obtained, set writeLock to 2 instead of
        ** the usual 1. This causes walIndexPage() to behave as if the
        ** write-lock were held (so that it allocates new pages as required),
        ** and walHandleException() to unlock the write-lock if a SEH exception
        ** is thrown.  */
        if( !bWriteLock ) pWal->writeLock = 2;
        if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
          badHdr = walIndexTryHdr(pWal, pChanged);
          if( badHdr ){
            /* If the wal-index header is still malformed even while holding
            ** a WRITE lock, it can only mean that the header is corrupted and
            ** needs to be reconstructed.  So run recovery to do exactly that.
            ** Disable blocking locks first.  */

}

/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/
SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal){
#ifndef SQLITE_ENABLE_SETLK_TIMEOUT
  assert( pWal->writeLock==0 || pWal->readLock<0 );
#endif
  if( pWal->readLock>=0 ){
    sqlite3WalEndWriteTransaction(pWal);
    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
    pWal->readLock = -1;
  }
}

/*
** Search the wal file for page pgno. If found, set *piRead to the frame that

  int rc;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  /* If the write-lock is already held, then it was obtained before the
  ** read-transaction was even opened, making this call a no-op.
  ** Return early. */
  if( pWal->writeLock ){
    assert( !memcmp(&pWal->hdr,(void*)pWal->apWiData[0],sizeof(WalIndexHdr)) );
    return SQLITE_OK;
  }
#endif

  /* Cannot start a write transaction without first holding a read
  ** transaction. */
  assert( pWal->readLock>=0 );

** root-node and 3 for all other internal nodes.
**
** If a tree that appears to be taller than this is encountered, it is
** assumed that the database is corrupt.
*/
#define BTCURSOR_MAX_DEPTH 20

/*
** Maximum amount of storage local to a database page, regardless of
** page size.
*/
#define BT_MAX_LOCAL  65501  /* 65536 - 35 */

/*
** A cursor is a pointer to a particular entry within a particular
** b-tree within a database file.
**
** The entry is identified by its MemPage and the index in
** MemPage.aCell[] of the entry.
**

** 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;
  u8 skipOk = 1;
  Btree *p;
  assert( sqlite3_mutex_held(db->mutex) );
  for(i=0; i<db->nDb; i++){
    p = db->aDb[i].pBt;
    if( p && p->sharable ){
      sqlite3BtreeEnter(p);
      skipOk = 0;

/*
** Provide flag hints to the cursor.
*/
SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor *pCur, unsigned x){
  assert( x==BTREE_SEEK_EQ || x==BTREE_BULKLOAD || x==0 );
  pCur->hints = (u8)x;
}


#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page
** number for the pointer-map page that contains the entry for the

/*
** Given a record with nPayload bytes of payload stored within btree
** page pPage, return the number of bytes of payload stored locally.
*/
static int btreePayloadToLocal(MemPage *pPage, i64 nPayload){
  int maxLocal;  /* Maximum amount of payload held locally */
  maxLocal = pPage->maxLocal;
  assert( nPayload>=0 );
  if( nPayload<=maxLocal ){
    return (int)nPayload;
  }else{
    int minLocal;  /* Minimum amount of payload held locally */
    int surplus;   /* Overflow payload available for local storage */
    minLocal = pPage->minLocal;
    surplus = (int)(minLocal +(nPayload - minLocal)%(pPage->pBt->usableSize-4));
    return (surplus <= maxLocal) ? surplus : minLocal;
  }
}

/*
** The following routines are implementations of the MemPage.xParseCell()
** method.
**

  pIter++;

  pInfo->nKey = *(i64*)&iKey;
  pInfo->nPayload = nPayload;
  pInfo->pPayload = pIter;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==(u32)pPage->maxLocal+1 );
  assert( nPayload>=0 );
  assert( pPage->maxLocal <= BT_MAX_LOCAL );
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */
    pInfo->nSize = (u16)nPayload + (u16)(pIter - pCell);
    if( pInfo->nSize<4 ) pInfo->nSize = 4;
    pInfo->nLocal = (u16)nPayload;
  }else{
    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
  }
}
static void btreeParseCellPtrIndex(

  }
  pIter++;
  pInfo->nKey = nPayload;
  pInfo->nPayload = nPayload;
  pInfo->pPayload = pIter;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==(u32)pPage->maxLocal+1 );
  assert( nPayload>=0 );
  assert( pPage->maxLocal <= BT_MAX_LOCAL );
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */
    pInfo->nSize = (u16)nPayload + (u16)(pIter - pCell);
    if( pInfo->nSize<4 ) pInfo->nSize = 4;
    pInfo->nLocal = (u16)nPayload;
  }else{
    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
  }
}
static void btreeParseCell(

**
** 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, int iStart, int iSize){
  int iPtr;                             /* Address of ptr to next freeblock */
  int iFreeBlk;                         /* Address of the next freeblock */
  u8 hdr;                               /* Page header size.  0 or 100 */
  int nFrag = 0;                        /* Reduction in fragmentation */
  int iOrigSize = iSize;                /* Original value of iSize */
  int x;                                /* Offset to cell content area */
  int iEnd = iStart + iSize;            /* First byte past the iStart buffer */
  unsigned char *data = pPage->aData;   /* Page content */
  u8 *pTmp;                             /* Temporary ptr into data[] */

  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( CORRUPT_DB || iStart>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( CORRUPT_DB || iEnd <= pPage->pBt->usableSize );

    while( (iFreeBlk = get2byte(&data[iPtr]))<iStart ){
      if( iFreeBlk<=iPtr ){
        if( iFreeBlk==0 ) break; /* TH3: corrupt082.100 */
        return SQLITE_CORRUPT_PAGE(pPage);
      }
      iPtr = iFreeBlk;
    }
    if( iFreeBlk>(int)pPage->pBt->usableSize-4 ){ /* TH3: corrupt081.100 */
      return SQLITE_CORRUPT_PAGE(pPage);
    }
    assert( iFreeBlk>iPtr || iFreeBlk==0 || CORRUPT_DB );

    /* At this point:
    **    iFreeBlk:   First freeblock after iStart, or zero if none
    **    iPtr:       The address of a pointer to iFreeBlk
    **
    ** Check to see if iFreeBlk should be coalesced onto the end of iStart.
    */
    if( iFreeBlk && iEnd+3>=iFreeBlk ){
      nFrag = iFreeBlk - iEnd;
      if( iEnd>iFreeBlk ) return SQLITE_CORRUPT_PAGE(pPage);
      iEnd = iFreeBlk + get2byte(&data[iFreeBlk+2]);
      if( iEnd > (int)pPage->pBt->usableSize ){
        return SQLITE_CORRUPT_PAGE(pPage);
      }
      iSize = iEnd - iStart;
      iFreeBlk = get2byte(&data[iFreeBlk]);
    }

    /* If iPtr is another freeblock (that is, if iPtr is not the freelist
    ** pointer in the page header) then check to see if iStart should be
    ** coalesced onto the end of iPtr.
    */
    if( iPtr>hdr+1 ){
      int iPtrEnd = iPtr + get2byte(&data[iPtr+2]);
      if( iPtrEnd+3>=iStart ){
        if( iPtrEnd>iStart ) return SQLITE_CORRUPT_PAGE(pPage);
        nFrag += iStart - iPtrEnd;
        iSize = iEnd - iPtr;
        iStart = iPtr;
      }
    }
    if( nFrag>data[hdr+7] ) return SQLITE_CORRUPT_PAGE(pPage);
    data[hdr+7] -= (u8)nFrag;
  }
  pTmp = &data[hdr+5];
  x = get2byte(pTmp);
  if( pPage->pBt->btsFlags & BTS_FAST_SECURE ){
    /* Overwrite deleted information with zeros when the secure_delete
    ** option is enabled */
    memset(&data[iStart], 0, iSize);
  }
  if( iStart<=x ){
    /* The new freeblock is at the beginning of the cell content area,
    ** so just extend the cell content area rather than create another
    ** freelist entry */
    if( iStart<x ) return SQLITE_CORRUPT_PAGE(pPage);
    if( iPtr!=hdr+1 ) return SQLITE_CORRUPT_PAGE(pPage);
    put2byte(&data[hdr+1], iFreeBlk);
    put2byte(&data[hdr+5], iEnd);
  }else{
    /* Insert the new freeblock into the freelist */
    put2byte(&data[iPtr], iStart);
    put2byte(&data[iStart], iFreeBlk);
    assert( iSize>=0 && iSize<=0xffff );
    put2byte(&data[iStart+2], (u16)iSize);
  }
  pPage->nFree += iOrigSize;
  return SQLITE_OK;
}

/*
** Decode the flags byte (the first byte of the header) for a page

  ** the b-tree page type. */
  if( decodeFlags(pPage, data[0]) ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
  pPage->maskPage = (u16)(pBt->pageSize - 1);
  pPage->nOverflow = 0;
  pPage->cellOffset = (u16)(pPage->hdrOffset + 8 + pPage->childPtrSize);
  pPage->aCellIdx = data + pPage->childPtrSize + 8;
  pPage->aDataEnd = pPage->aData + pBt->pageSize;
  pPage->aDataOfst = pPage->aData + pPage->childPtrSize;
  /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
  ** number of cells on the page. */
  pPage->nCell = get2byte(&data[3]);
  if( pPage->nCell>MX_CELL(pBt) ){

/*
** Set up a raw page so that it looks like a database page holding
** no entries.
*/
static void zeroPage(MemPage *pPage, int flags){
  unsigned char *data = pPage->aData;
  BtShared *pBt = pPage->pBt;
  int hdr = pPage->hdrOffset;
  int first;

  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno || CORRUPT_DB );
  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pBt->btsFlags & BTS_FAST_SECURE ){
    memset(&data[hdr], 0, pBt->usableSize - hdr);
  }
  data[hdr] = (char)flags;
  first = hdr + ((flags&PTF_LEAF)==0 ? 12 : 8);
  memset(&data[hdr+1], 0, 4);
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
  pPage->nFree = (u16)(pBt->usableSize - first);
  decodeFlags(pPage, flags);
  pPage->cellOffset = (u16)first;
  pPage->aDataEnd = &data[pBt->pageSize];
  pPage->aCellIdx = &data[first];
  pPage->aDataOfst = &data[pPage->childPtrSize];
  pPage->nOverflow = 0;
  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
  pPage->maskPage = (u16)(pBt->pageSize - 1);
  pPage->nCell = 0;

*/
SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
  int rc = SQLITE_OK;
  int x;
  BtShared *pBt = p->pBt;
  assert( nReserve>=0 && nReserve<=255 );
  sqlite3BtreeEnter(p);
  pBt->nReserveWanted = (u8)nReserve;
  x = pBt->pageSize - pBt->usableSize;
  if( nReserve<x ) nReserve = x;
  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
    sqlite3BtreeLeave(p);
    return SQLITE_READONLY;
  }
  assert( nReserve>=0 && nReserve<=255 );

  int b;
  if( p==0 ) return 0;
  sqlite3BtreeEnter(p);
  assert( BTS_OVERWRITE==BTS_SECURE_DELETE*2 );
  assert( BTS_FAST_SECURE==(BTS_OVERWRITE|BTS_SECURE_DELETE) );
  if( newFlag>=0 ){
    p->pBt->btsFlags &= ~BTS_FAST_SECURE;
    p->pBt->btsFlags |= (u16)(BTS_SECURE_DELETE*newFlag);
  }
  b = (p->pBt->btsFlags & BTS_FAST_SECURE)/BTS_SECURE_DELETE;
  sqlite3BtreeLeave(p);
  return b;
}

/*

    if( pCArray->ixNx[k]<=i ){
      k++;
      pSrcEnd = pCArray->apEnd[k];
    }
  }

  /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
  assert( nCell < 10922 );
  pPg->nCell = (u16)nCell;
  pPg->nOverflow = 0;

  put2byte(&aData[hdr+1], 0);
  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);
  aData[hdr+7] = 0x00;
  return SQLITE_OK;

  /* Append cells to the end of the page */
  assert( nCell>=0 );
  pCellptr = &pPg->aCellIdx[nCell*2];
  if( pageInsertArray(
        pPg, pBegin, &pData, pCellptr,
        iNew+nCell, nNew-nCell, pCArray
      )
  ){
    goto editpage_fail;
  }

  assert( nNew < 10922 );
  pPg->nCell = (u16)nNew;
  pPg->nOverflow = 0;

  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);

#ifdef SQLITE_DEBUG
  for(i=0; i<nNew && !CORRUPT_DB; i++){

  int rc = SQLITE_OK;          /* The return code */
  u16 leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */
  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
  u64 szScratch;               /* Size of scratch memory requested */
  MemPage *apOld[NB];          /* pPage and up to two siblings */
  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  u8 *pRight;                  /* Location in parent of right-sibling pointer */
  u8 *apDiv[NB-1];             /* Divider cells in pParent */
  int cntNew[NB+2];            /* Index in b.paCell[] of cell after i-th page */
  int cntOld[NB+2];            /* Old index in b.apCell[] */
  int szNew[NB+2];             /* Combined size of cells placed on i-th page */

    ** overwrite optimization.
    */
    if( loc==0 ){
      getCellInfo(pCur);
      if( pCur->info.nKey==pX->nKey ){
        BtreePayload x2;
        x2.pData = pX->pKey;
        x2.nData = (int)pX->nKey;  assert( pX->nKey<=0x7fffffff );
        x2.nZero = 0;
        return btreeOverwriteCell(pCur, &x2);
      }
    }
  }
  assert( pCur->eState==CURSOR_VALID
       || (pCur->eState==CURSOR_INVALID && loc) || CORRUPT_DB );

  u8 *aOut = pBt->pTmpSpace;    /* Pointer to next output buffer */
  const u8 *aIn;                /* Pointer to next input buffer */
  u32 nIn;                      /* Size of input buffer aIn[] */
  u32 nRem;                     /* Bytes of data still to copy */

  getCellInfo(pSrc);
  if( pSrc->info.nPayload<0x80 ){
    *(aOut++) = (u8)pSrc->info.nPayload;
  }else{
    aOut += sqlite3PutVarint(aOut, pSrc->info.nPayload);
  }
  if( pDest->pKeyInfo==0 ) aOut += putVarint(aOut, iKey);
  nIn = pSrc->info.nLocal;
  aIn = pSrc->info.pPayload;
  if( aIn+nIn>pSrc->pPage->aDataEnd ){
    return SQLITE_CORRUPT_PAGE(pSrc->pPage);
  }
  nRem = pSrc->info.nPayload;
  if( nIn==nRem && nIn<pDest->pPage->maxLocal ){
    memcpy(aOut, aIn, nIn);
    pBt->nPreformatSize = nIn + (int)(aOut - pBt->pTmpSpace);
    return SQLITE_OK;
  }else{
    int rc = SQLITE_OK;
    Pager *pSrcPager = pSrc->pBt->pPager;
    u8 *pPgnoOut = 0;
    Pgno ovflIn = 0;
    DbPage *pPageIn = 0;
    MemPage *pPageOut = 0;
    u32 nOut;                     /* Size of output buffer aOut[] */

    nOut = btreePayloadToLocal(pDest->pPage, pSrc->info.nPayload);
    pBt->nPreformatSize = (int)nOut + (int)(aOut - pBt->pTmpSpace);
    if( nOut<pSrc->info.nPayload ){
      pPgnoOut = &aOut[nOut];
      pBt->nPreformatSize += 4;
    }

    if( nRem>nIn ){
      if( aIn+nIn+4>pSrc->pPage->aDataEnd ){

**
** A single int or real value always converts to the same strings.  But
** many different strings can be converted into the same int or real.
** If a table contains a numeric value and an index is based on the
** corresponding string value, then it is important that the string be
** derived from the numeric value, not the other way around, to ensure
** that the index and table are consistent.  See ticket
** https://sqlite.org/src/info/343634942dd54ab (2018-01-31) for
** an example.
**
** This routine looks at pMem to verify that if it has both a numeric
** representation and a string representation then the string rep has
** been derived from the numeric and not the other way around.  It returns
** true if everything is ok and false if there is a problem.
**

  int p2,               /* First argument register */
  int p3,               /* Register into which results are written */
  int nArg,             /* Number of argument */
  const FuncDef *pFunc, /* The function to be invoked */
  int eCallCtx          /* Calling context */
){
  Vdbe *v = pParse->pVdbe;

  int addr;
  sqlite3_context *pCtx;
  assert( v );

  pCtx = sqlite3DbMallocRawNN(pParse->db, SZ_CONTEXT(nArg));
  if( pCtx==0 ){
    assert( pParse->db->mallocFailed );
    freeEphemeralFunction(pParse->db, (FuncDef*)pFunc);
    return 0;
  }
  pCtx->pOut = 0;
  pCtx->pFunc = (FuncDef*)pFunc;

/*
** If the previous opcode is an OP_Column that delivers results
** into register iDest, then add the OPFLAG_TYPEOFARG flag to that
** opcode.
*/
SQLITE_PRIVATE void sqlite3VdbeTypeofColumn(Vdbe *p, int iDest){
  VdbeOp *pOp = sqlite3VdbeGetLastOp(p);
#ifdef SQLITE_DEBUG
  while( pOp->opcode==OP_ReleaseReg ) pOp--;
#endif
  if( pOp->p3==iDest && pOp->opcode==OP_Column ){
    pOp->p5 |= OPFLAG_TYPEOFARG;
  }
}

/*
** Change the P2 operand of instruction addr so that it points to

       || (pCsr->nField==nRealCol+1 && op==SQLITE_DELETE && iReg==-1)
  );

  preupdate.v = v;
  preupdate.pCsr = pCsr;
  preupdate.op = op;
  preupdate.iNewReg = iReg;
  preupdate.pKeyinfo = (KeyInfo*)&preupdate.keyinfoSpace;
  preupdate.pKeyinfo->db = db;
  preupdate.pKeyinfo->enc = ENC(db);
  preupdate.pKeyinfo->nKeyField = pTab->nCol;
  preupdate.pKeyinfo->aSortFlags = (u8*)&fakeSortOrder;
  preupdate.iKey1 = iKey1;
  preupdate.iKey2 = iKey2;
  preupdate.pTab = pTab;
  preupdate.iBlobWrite = iBlobWrite;

  db->pPreUpdate = &preupdate;
  db->xPreUpdateCallback(db->pPreUpdateArg, db, op, zDb, zTbl, iKey1, iKey2);
  db->pPreUpdate = 0;
  sqlite3DbFree(db, preupdate.aRecord);
  vdbeFreeUnpacked(db, preupdate.pKeyinfo->nKeyField+1,preupdate.pUnpacked);
  vdbeFreeUnpacked(db, preupdate.pKeyinfo->nKeyField+1,preupdate.pNewUnpacked);
  sqlite3VdbeMemRelease(&preupdate.oldipk);
  if( preupdate.aNew ){
    int i;
    for(i=0; i<pCsr->nField; i++){
      sqlite3VdbeMemRelease(&preupdate.aNew[i]);
    }
    sqlite3DbNNFreeNN(db, preupdate.aNew);

  sqlite3_uint64 nData,
  void (*xDel)(void*),
  unsigned char enc
){
  assert( xDel!=SQLITE_DYNAMIC );
  if( enc!=SQLITE_UTF8 ){
    if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
    nData &= ~(u64)1;
  }
  return bindText(pStmt, i, zData, nData, xDel, enc);
}
#ifndef SQLITE_OMIT_UTF16
SQLITE_API int sqlite3_bind_text16(
  sqlite3_stmt *pStmt,
  int i,

      assert( p->pCsr->eCurType==CURTYPE_BTREE );
      nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
      aRec = sqlite3DbMallocRaw(db, nRec);
      if( !aRec ) goto preupdate_old_out;
      rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
      if( rc==SQLITE_OK ){
        p->pUnpacked = vdbeUnpackRecord(p->pKeyinfo, nRec, aRec);
        if( !p->pUnpacked ) rc = SQLITE_NOMEM;
      }
      if( rc!=SQLITE_OK ){
        sqlite3DbFree(db, aRec);
        goto preupdate_old_out;
      }
      p->aRecord = aRec;

SQLITE_API int sqlite3_preupdate_count(sqlite3 *db){
  PreUpdate *p;
#ifdef SQLITE_ENABLE_API_ARMOR
  p = db!=0 ? db->pPreUpdate : 0;
#else
  p = db->pPreUpdate;
#endif
  return (p ? p->pKeyinfo->nKeyField : 0);
}
#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
/*
** This function is designed to be called from within a pre-update callback
** only. It returns zero if the change that caused the callback was made

    /* For an INSERT, memory cell p->iNewReg contains the serialized record
    ** that is being inserted. Deserialize it. */
    UnpackedRecord *pUnpack = p->pNewUnpacked;
    if( !pUnpack ){
      Mem *pData = &p->v->aMem[p->iNewReg];
      rc = ExpandBlob(pData);
      if( rc!=SQLITE_OK ) goto preupdate_new_out;
      pUnpack = vdbeUnpackRecord(p->pKeyinfo, pData->n, pData->z);
      if( !pUnpack ){
        rc = SQLITE_NOMEM;
        goto preupdate_new_out;
      }
      p->pNewUnpacked = pUnpack;
    }
    pMem = &pUnpack->aMem[iStore];

  ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
  ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
  */
  Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;

  i64 nByte;
  VdbeCursor *pCx = 0;
  nByte = SZ_VDBECURSOR(nField);
  assert( ROUND8(nByte)==nByte );
  if( eCurType==CURTYPE_BTREE ) nByte += sqlite3BtreeCursorSize();

  assert( iCur>=0 && iCur<p->nCursor );
  if( p->apCsr[iCur] ){ /*OPTIMIZATION-IF-FALSE*/
    sqlite3VdbeFreeCursorNN(p, p->apCsr[iCur]);
    p->apCsr[iCur] = 0;
  }

  p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->zMalloc;
  memset(pCx, 0, offsetof(VdbeCursor,pAltCursor));
  pCx->eCurType = eCurType;
  pCx->nField = nField;
  pCx->aOffset = &pCx->aType[nField];
  if( eCurType==CURTYPE_BTREE ){
    assert( ROUND8(SZ_VDBECURSOR(nField))==SZ_VDBECURSOR(nField) );
    pCx->uc.pCursor = (BtCursor*)&pMem->z[SZ_VDBECURSOR(nField)];

    sqlite3BtreeCursorZero(pCx->uc.pCursor);
  }
  return pCx;
}

/*
** The string in pRec is known to look like an integer and to have a

      if( pOp->p4.z ){
        p->zErrMsg = sqlite3MPrintf(db, "%z: %s", p->zErrMsg, pOp->p4.z);
      }
    }else{
      sqlite3VdbeError(p, "%s", pOp->p4.z);
    }
    pcx = (int)(pOp - aOp);
    sqlite3_log(pOp->p1, "abort at %d: %s; [%s]", pcx, p->zErrMsg, p->zSql);
  }
  rc = sqlite3VdbeHalt(p);
  assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
  if( rc==SQLITE_BUSY ){
    p->rc = SQLITE_BUSY;
  }else{
    assert( rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT );

  if( (pIn1->flags & MEM_Null)==0 ){
    pOut->flags = MEM_Int;
    pOut->u.i = ~sqlite3VdbeIntValue(pIn1);
  }
  break;
}

/* Opcode: Once P1 P2 P3 * *
**
** Fall through to the next instruction the first time this opcode is
** encountered on each invocation of the byte-code program.  Jump to P2
** on the second and all subsequent encounters during the same invocation.
**
** Top-level programs determine first invocation by comparing the P1
** operand against the P1 operand on the OP_Init opcode at the beginning
** of the program.  If the P1 values differ, then fall through and make
** the P1 of this opcode equal to the P1 of OP_Init.  If P1 values are
** the same then take the jump.
**
** For subprograms, there is a bitmask in the VdbeFrame that determines
** whether or not the jump should be taken.  The bitmask is necessary
** because the self-altering code trick does not work for recursive
** triggers.
**
** The P3 operand is not used directly by this opcode.  However P3 is
** used by the code generator as follows:  If this opcode is the start
** of a subroutine and that subroutine uses a Bloom filter, then P3 will
** be the register that holds that Bloom filter.  See tag-202407032019
** in the source code for implementation details.
*/
case OP_Once: {             /* jump */
  u32 iAddr;                /* Address of this instruction */
  assert( p->aOp[0].opcode==OP_Init );
  if( p->pFrame ){
    iAddr = (int)(pOp - p->aOp);
    if( (p->pFrame->aOnce[iAddr/8] & (1<<(iAddr & 7)))!=0 ){

        memcpy(zPayload, pRec->z, pRec->n);
        zPayload += pRec->n;
      }
    }else{
      zHdr += sqlite3PutVarint(zHdr, serial_type);
      if( pRec->n ){
        assert( pRec->z!=0 );
        assert( pRec->z!=(const char*)sqlite3CtypeMap );
        memcpy(zPayload, pRec->z, pRec->n);
        zPayload += pRec->n;
      }
    }
    if( pRec==pLast ) break;
    pRec++;
  }

  assert( pC->nullRow==0 );
  assert( pC->uc.pCursor!=0 );
  pCrsr = pC->uc.pCursor;

  /* The OP_RowData opcodes always follow OP_NotExists or
  ** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
  ** that might invalidate the cursor.
  ** If this were not the case, one of the following assert()s
  ** would fail.  Should this ever change (because of changes in the code
  ** generator) then the fix would be to insert a call to
  ** sqlite3VdbeCursorMoveto().
  */
  assert( pC->deferredMoveto==0 );
  assert( sqlite3BtreeCursorIsValid(pCrsr) );

  /* Allocate space for (a) the context object and (n-1) extra pointers
  ** to append to the sqlite3_context.argv[1] array, and (b) a memory
  ** cell in which to store the accumulation. Be careful that the memory
  ** cell is 8-byte aligned, even on platforms where a pointer is 32-bits.
  **
  ** Note: We could avoid this by using a regular memory cell from aMem[] for
  ** the accumulator, instead of allocating one here. */
  nAlloc = ROUND8P( SZ_CONTEXT(n) );
  pCtx = sqlite3DbMallocRawNN(db, nAlloc + sizeof(Mem));
  if( pCtx==0 ) goto no_mem;
  pCtx->pOut = (Mem*)((u8*)pCtx + nAlloc);
  assert( EIGHT_BYTE_ALIGNMENT(pCtx->pOut) );

  sqlite3VdbeMemInit(pCtx->pOut, db, MEM_Null);
  pCtx->pMem = 0;

#endif
  if( p->zErrMsg==0 && rc!=SQLITE_IOERR_NOMEM ){
    sqlite3VdbeError(p, "%s", sqlite3ErrStr(rc));
  }
  p->rc = rc;
  sqlite3SystemError(db, rc);
  testcase( sqlite3GlobalConfig.xLog!=0 );
  sqlite3_log(rc, "statement aborts at %d: %s; [%s]",
                   (int)(pOp - aOp), p->zErrMsg, p->zSql);
  if( p->eVdbeState==VDBE_RUN_STATE ) sqlite3VdbeHalt(p);
  if( rc==SQLITE_IOERR_NOMEM ) sqlite3OomFault(db);
  if( rc==SQLITE_CORRUPT && db->autoCommit==0 ){
    db->flags |= SQLITE_CorruptRdOnly;
  }
  rc = SQLITE_ERROR;
  if( resetSchemaOnFault>0 ){

){
  int nAttempt = 0;
  int iCol;               /* Index of zColumn in row-record */
  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;
  Incrblob *pBlob = 0;
  int iDb;
  Parse sParse;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( ppBlob==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif

    }
#ifndef SQLITE_OMIT_VIEW
    if( pTab && IsView(pTab) ){
      pTab = 0;
      sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
    }
#endif
    if( pTab==0
     || ((iDb = sqlite3SchemaToIndex(db, pTab->pSchema))==1 &&
         sqlite3OpenTempDatabase(&sParse))
    ){
      if( sParse.zErrMsg ){
        sqlite3DbFree(db, zErr);
        zErr = sParse.zErrMsg;
        sParse.zErrMsg = 0;
      }
      rc = SQLITE_ERROR;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }
    pBlob->pTab = pTab;
    pBlob->zDb = db->aDb[iDb].zDbSName;

    /* Now search pTab for the exact column. */
    iCol = sqlite3ColumnIndex(pTab, zColumn);
    if( iCol<0 ){
      sqlite3DbFree(db, zErr);
      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
      rc = SQLITE_ERROR;

        /* blobSeekToRow() will initialize r[1] to the desired rowid */
        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
        {OP_Column,         0, 0, 1},  /* 3  */
        {OP_ResultRow,      1, 0, 0},  /* 4  */
        {OP_Halt,           0, 0, 0},  /* 5  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;

      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, wrFlag,
                           pTab->pSchema->schema_cookie,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);
      assert( sqlite3VdbeCurrentAddr(v)==2 || db->mallocFailed );

  int iMemory;                    /* Offset of free space in list.aMemory */
  int nMemory;                    /* Size of list.aMemory allocation in bytes */
  u8 bUsePMA;                     /* True if one or more PMAs created */
  u8 bUseThreads;                 /* True to use background threads */
  u8 iPrev;                       /* Previous thread used to flush PMA */
  u8 nTask;                       /* Size of aTask[] array */
  u8 typeMask;
  SortSubtask aTask[FLEXARRAY];   /* One or more subtasks */
};

/* Size (in bytes) of a VdbeSorter object that works with N or fewer subtasks */
#define SZ_VDBESORTER(N)  (offsetof(VdbeSorter,aTask)+(N)*sizeof(SortSubtask))

#define SORTER_TYPE_INTEGER 0x01
#define SORTER_TYPE_TEXT    0x02

/*
** An instance of the following object is used to read records out of a
** PMA, in sorted order.  The next key to be read is cached in nKey/aKey.

#endif

  assert( pCsr->pKeyInfo );
  assert( !pCsr->isEphemeral );
  assert( pCsr->eCurType==CURTYPE_SORTER );
  assert( sizeof(KeyInfo) + UMXV(pCsr->pKeyInfo->nKeyField)*sizeof(CollSeq*)
               < 0x7fffffff );
  szKeyInfo = SZ_KEYINFO(pCsr->pKeyInfo->nKeyField+1);
  sz = SZ_VDBESORTER(nWorker+1);

  pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo);
  pCsr->uc.pSorter = pSorter;
  if( pSorter==0 ){
    rc = SQLITE_NOMEM_BKPT;
  }else{
    Btree *pBt = db->aDb[0].pBt;

    }else{
      pNext = p->u.pNext;
    }

    p->u.pNext = 0;
    for(i=0; aSlot[i]; i++){
      p = vdbeSorterMerge(pTask, p, aSlot[i]);
      /* ,--Each aSlot[] holds twice as much as the previous. So we cannot use
      ** |  up all 64 aSlots[] with only a 64-bit address space.
      ** v                                                                */
      assert( i<ArraySize(aSlot) );
      aSlot[i] = 0;
    }
    aSlot[i] = p;
    p = pNext;
  }

  p = 0;

SQLITE_PRIVATE int sqlite3ResolveSelfReference(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* The table being referenced, or NULL */
  int type,        /* NC_IsCheck, NC_PartIdx, NC_IdxExpr, NC_GenCol, or 0 */
  Expr *pExpr,     /* Expression to resolve.  May be NULL. */
  ExprList *pList  /* Expression list to resolve.  May be NULL. */
){
  SrcList *pSrc;                  /* Fake SrcList for pParse->pNewTable */
  NameContext sNC;                /* Name context for pParse->pNewTable */
  int rc;
  u8 srcSpace[SZ_SRCLIST_1];     /* Memory space for the fake SrcList */

  assert( type==0 || pTab!=0 );
  assert( type==NC_IsCheck || type==NC_PartIdx || type==NC_IdxExpr
          || type==NC_GenCol || pTab==0 );
  memset(&sNC, 0, sizeof(sNC));
  pSrc = (SrcList*)srcSpace;
  memset(pSrc, 0, SZ_SRCLIST_1);
  if( pTab ){
    pSrc->nSrc = 1;
    pSrc->a[0].zName = pTab->zName;
    pSrc->a[0].pSTab = pTab;
    pSrc->a[0].iCursor = -1;
    if( pTab->pSchema!=pParse->db->aDb[1].pSchema ){
      /* Cause EP_FromDDL to be set on TK_FUNCTION nodes of non-TEMP
      ** schema elements */
      type |= NC_FromDDL;
    }
  }
  sNC.pParse = pParse;
  sNC.pSrcList = pSrc;
  sNC.ncFlags = type | NC_IsDDL;
  if( (rc = sqlite3ResolveExprNames(&sNC, pExpr))!=SQLITE_OK ) return rc;
  if( pList ) rc = sqlite3ResolveExprListNames(&sNC, pList);
  return rc;
}

/************** End of resolve.c *********************************************/

** argument. If an OOM condition is encountered, NULL is returned
** and the db->mallocFailed flag set.
*/
#ifndef SQLITE_OMIT_CTE
SQLITE_PRIVATE With *sqlite3WithDup(sqlite3 *db, With *p){
  With *pRet = 0;
  if( p ){
    sqlite3_int64 nByte = SZ_WITH(p->nCte);
    pRet = sqlite3DbMallocZero(db, nByte);
    if( pRet ){
      int i;
      pRet->nCte = p->nCte;
      for(i=0; i<p->nCte; i++){
        pRet->a[i].pSelect = sqlite3SelectDup(db, p->a[i].pSelect, 0);
        pRet->a[i].pCols = sqlite3ExprListDup(db, p->a[i].pCols, 0);

** called with a NULL argument.
*/
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
 || !defined(SQLITE_OMIT_SUBQUERY)
SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
  SrcList *pNew;
  int i;

  assert( db!=0 );
  if( p==0 ) return 0;

  pNew = sqlite3DbMallocRawNN(db, SZ_SRCLIST(p->nSrc) );
  if( pNew==0 ) return 0;
  pNew->nSrc = pNew->nAlloc = p->nSrc;
  for(i=0; i<p->nSrc; i++){
    SrcItem *pNewItem = &pNew->a[i];
    const SrcItem *pOldItem = &p->a[i];
    Table *pTab;
    pNewItem->fg = pOldItem->fg;

  return pNew;
}
SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, const IdList *p){
  IdList *pNew;
  int i;
  assert( db!=0 );
  if( p==0 ) return 0;
  pNew = sqlite3DbMallocRawNN(db, SZ_IDLIST(p->nId));
  if( pNew==0 ) return 0;
  pNew->nId = p->nId;
  for(i=0; i<p->nId; i++){
    struct IdList_item *pNewItem = &pNew->a[i];
    const struct IdList_item *pOldItem = &p->a[i];
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
  }

    pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, flags);
    pNew->op = p->op;
    pNew->pNext = pNext;
    pNew->pPrior = 0;
    pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
    pNew->iLimit = 0;
    pNew->iOffset = 0;
    pNew->selFlags = p->selFlags & ~(u32)SF_UsesEphemeral;
    pNew->addrOpenEphm[0] = -1;
    pNew->addrOpenEphm[1] = -1;
    pNew->nSelectRow = p->nSelectRow;
    pNew->pWith = sqlite3WithDup(db, p->pWith);
#ifndef SQLITE_OMIT_WINDOWFUNC
    pNew->pWin = 0;
    pNew->pWinDefn = sqlite3WindowListDup(db, p->pWinDefn);

SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendNew(
  sqlite3 *db,            /* Database handle.  Used for memory allocation */
  Expr *pExpr             /* Expression to be appended. Might be NULL */
){
  struct ExprList_item *pItem;
  ExprList *pList;

  pList = sqlite3DbMallocRawNN(db, SZ_EXPRLIST(4));
  if( pList==0 ){
    sqlite3ExprDelete(db, pExpr);
    return 0;
  }
  pList->nAlloc = 4;
  pList->nExpr = 1;
  pItem = &pList->a[0];
  *pItem = zeroItem;
  pItem->pExpr = pExpr;
  return pList;
}
SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendGrow(
  sqlite3 *db,            /* Database handle.  Used for memory allocation */
  ExprList *pList,        /* List to which to append. Might be NULL */
  Expr *pExpr             /* Expression to be appended. Might be NULL */
){
  struct ExprList_item *pItem;
  ExprList *pNew;
  pList->nAlloc *= 2;
  pNew = sqlite3DbRealloc(db, pList, SZ_EXPRLIST(pList->nAlloc));

  if( pNew==0 ){
    sqlite3ExprListDelete(db, pList);
    sqlite3ExprDelete(db, pExpr);
    return 0;
  }else{
    pList = pNew;
  }

      testcase( pSelect->selFlags & SF_Distinct );
      testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
      pCopy = sqlite3SelectDup(pParse->db, pSelect, 0);
      rc = pParse->db->mallocFailed ? 1 :sqlite3Select(pParse, pCopy, &dest);
      sqlite3SelectDelete(pParse->db, pCopy);
      sqlite3DbFree(pParse->db, dest.zAffSdst);
      if( addrBloom ){
        /* Remember that location of the Bloom filter in the P3 operand
        ** of the OP_Once that began this subroutine. tag-202407032019 */
        sqlite3VdbeGetOp(v, addrOnce)->p3 = dest.iSDParm2;
        if( dest.iSDParm2==0 ){
          /* If the Bloom filter won't actually be used, keep it small */

          sqlite3VdbeGetOp(v, addrBloom)->p1 = 10;
        }
      }
      if( rc ){
        sqlite3KeyInfoUnref(pKeyInfo);
        return;
      }
      assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */

  }else{
    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
    if( destIfFalse==destIfNull ){
      /* Combine Step 3 and Step 5 into a single opcode */
      if( ExprHasProperty(pExpr, EP_Subrtn) ){
        const VdbeOp *pOp = sqlite3VdbeGetOp(v, pExpr->y.sub.iAddr);
        assert( pOp->opcode==OP_Once || pParse->nErr );
        if( pOp->opcode==OP_Once && pOp->p3>0 ){  /* tag-202407032019 */
          assert( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) );
          sqlite3VdbeAddOp4Int(v, OP_Filter, pOp->p3, destIfFalse,
                               rLhs, nVector); VdbeCoverage(v);
        }
      }
      sqlite3VdbeAddOp4Int(v, OP_NotFound, iTab, destIfFalse,
                           rLhs, nVector); VdbeCoverage(v);

    return target;
  }
  return -1;  /* Not found */
}


/*
** Expression pExpr is guaranteed to be a TK_COLUMN or equivalent. This
** function checks the Parse.pIdxPartExpr list to see if this column
** can be replaced with a constant value. If so, it generates code to
** put the constant value in a register (ideally, but not necessarily,
** register iTarget) and returns the register number.
**
** Or, if the TK_COLUMN cannot be replaced by a constant, zero is
** returned.

      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      assert( regFree1==0 || regFree1==r1 );
      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
      sqlite3VdbeAddOp2(v, op, r1, dest);
      VdbeCoverageIf(v, op==TK_ISNULL);
      VdbeCoverageIf(v, op==TK_NOTNULL);

      break;
    }
    case TK_BETWEEN: {
      testcase( jumpIfNull==0 );
      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfTrue, jumpIfNull);
      break;
    }

      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      assert( regFree1==0 || regFree1==r1 );
      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
      sqlite3VdbeAddOp2(v, op, r1, dest);
      testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
      testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);

      break;
    }
    case TK_BETWEEN: {
      testcase( jumpIfNull==0 );
      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfFalse, jumpIfNull);
      break;
    }

  if( !pNew ) goto exit_begin_add_column;
  pParse->pNewTable = pNew;
  pNew->nTabRef = 1;
  pNew->nCol = pTab->nCol;
  assert( pNew->nCol>0 );
  nAlloc = (((pNew->nCol-1)/8)*8)+8;
  assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
  pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*(u32)nAlloc);
  pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
  if( !pNew->aCol || !pNew->zName ){
    assert( db->mallocFailed );
    goto exit_begin_add_column;
  }
  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*(size_t)pNew->nCol);
  for(i=0; i<pNew->nCol; i++){
    Column *pCol = &pNew->aCol[i];
    pCol->zCnName = sqlite3DbStrDup(db, pCol->zCnName);
    pCol->hName = sqlite3StrIHash(pCol->zCnName);
  }
  assert( IsOrdinaryTable(pNew) );
  pNew->u.tab.pDfltList = sqlite3ExprListDup(db, pTab->u.tab.pDfltList, 0);

  Parse *p,                       /* Memory to use for Parse object */
  const char *zDb,                /* Name of schema SQL belongs to */
  sqlite3 *db,                    /* Database handle */
  const char *zSql,               /* SQL to parse */
  int bTemp                       /* True if SQL is from temp schema */
){
  int rc;
  u64 flags;

  sqlite3ParseObjectInit(p, db);
  if( zSql==0 ){
    return SQLITE_NOMEM;
  }
  if( sqlite3StrNICmp(zSql,"CREATE ",7)!=0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  if( bTemp ){
    db->init.iDb = 1;
  }else{
    int iDb = sqlite3FindDbName(db, zDb);
    assert( iDb>=0 && iDb<=0xff );
    db->init.iDb = (u8)iDb;
  }
  p->eParseMode = PARSE_MODE_RENAME;
  p->db = db;
  p->nQueryLoop = 1;
  flags = db->flags;
  testcase( (db->flags & SQLITE_Comments)==0 && strstr(zSql," /* ")!=0 );
  db->flags |= SQLITE_Comments;
  rc = sqlite3RunParser(p, zSql);
  db->flags = flags;
  if( db->mallocFailed ) rc = SQLITE_NOMEM;
  if( rc==SQLITE_OK
   && NEVER(p->pNewTable==0 && p->pNewIndex==0 && p->pNewTrigger==0)
  ){
    rc = SQLITE_CORRUPT_BKPT;
  }

    zQuot = sqlite3MPrintf(db, "\"%w\" ", zNew);
    if( zQuot==0 ){
      return SQLITE_NOMEM;
    }else{
      nQuot = sqlite3Strlen30(zQuot)-1;
    }

    assert( nQuot>=nNew && nSql>=0 && nNew>=0 );
    zOut = sqlite3DbMallocZero(db, (u64)(nSql + pRename->nList*nQuot + 1));
  }else{
    assert( nSql>0 );
    zOut = (char*)sqlite3DbMallocZero(db, (u64)(nSql*2+1) * 3);
    if( zOut ){
      zBuf1 = &zOut[nSql*2+1];
      zBuf2 = &zOut[nSql*4+2];
    }
  }

  /* At this point pRename->pList contains a list of RenameToken objects
  ** corresponding to all tokens in the input SQL that must be replaced
  ** with the new column name, or with single-quoted versions of themselves.
  ** All that remains is to construct and return the edited SQL string. */
  if( zOut ){
    i64 nOut = nSql;
    assert( nSql>0 );
    memcpy(zOut, zSql, (size_t)nSql);
    while( pRename->pList ){
      int iOff;                   /* Offset of token to replace in zOut */
      i64 nReplace;
      const char *zReplace;
      RenameToken *pBest = renameColumnTokenNext(pRename);

      if( zNew ){
        if( bQuote==0 && sqlite3IsIdChar(*(u8*)pBest->t.z) ){
          nReplace = nNew;
          zReplace = zNew;
        }else{
          nReplace = nQuot;
          zReplace = zQuot;
          if( pBest->t.z[pBest->t.n]=='"' ) nReplace++;
        }
      }else{
        /* Dequote the double-quoted token. Then requote it again, this time
        ** using single quotes. If the character immediately following the
        ** original token within the input SQL was a single quote ('), then
        ** add another space after the new, single-quoted version of the
        ** token. This is so that (SELECT "string"'alias') maps to
        ** (SELECT 'string' 'alias'), and not (SELECT 'string''alias').  */
        memcpy(zBuf1, pBest->t.z, pBest->t.n);
        zBuf1[pBest->t.n] = 0;
        sqlite3Dequote(zBuf1);
        assert( nSql < 0x15555554 /* otherwise malloc would have failed */ );
        sqlite3_snprintf((int)(nSql*2), zBuf2, "%Q%s", zBuf1,
            pBest->t.z[pBest->t.n]=='\'' ? " " : ""
        );
        zReplace = zBuf2;
        nReplace = sqlite3Strlen30(zReplace);
      }

      iOff = (int)(pBest->t.z - zSql);
      if( pBest->t.n!=nReplace ){
        memmove(&zOut[iOff + nReplace], &zOut[iOff + pBest->t.n],
            nOut - (iOff + pBest->t.n)
        );
        nOut += nReplace - pBest->t.n;
        zOut[nOut] = '\0';
      }

  return rc;
}

/*
** Set all pEList->a[].fg.eEName fields in the expression-list to val.
*/
static void renameSetENames(ExprList *pEList, int val){
  assert( val==ENAME_NAME || val==ENAME_TAB || val==ENAME_SPAN );
  if( pEList ){
    int i;
    for(i=0; i<pEList->nExpr; i++){
      assert( val==ENAME_NAME || pEList->a[i].fg.eEName==ENAME_NAME );
      pEList->a[i].fg.eEName = val&0x3;
    }
  }
}

/*
** Resolve all symbols in the trigger at pParse->pNewTrigger, assuming
** it was read from the schema of database zDb. Return SQLITE_OK if

  sWalker.u.pRename = &sCtx;

  sCtx.pTab = pTab;
  if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
  if( sParse.pNewTable ){
    if( IsView(sParse.pNewTable) ){
      Select *pSelect = sParse.pNewTable->u.view.pSelect;
      pSelect->selFlags &= ~(u32)SF_View;
      sParse.rc = SQLITE_OK;
      sqlite3SelectPrep(&sParse, pSelect, 0);
      rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
      if( rc==SQLITE_OK ){
        sqlite3WalkSelect(&sWalker, pSelect);
      }
      if( rc!=SQLITE_OK ) goto renameColumnFunc_done;

          if( isLegacy==0 ){
            Select *pSelect = pTab->u.view.pSelect;
            NameContext sNC;
            memset(&sNC, 0, sizeof(sNC));
            sNC.pParse = &sParse;

            assert( pSelect->selFlags & SF_View );
            pSelect->selFlags &= ~(u32)SF_View;
            sqlite3SelectPrep(&sParse, pTab->u.view.pSelect, &sNC);
            if( sParse.nErr ){
              rc = sParse.rc;
            }else{
              sqlite3WalkSelect(&sWalker, pTab->u.view.pSelect);
            }
          }

      sWalker.xExprCallback = renameQuotefixExprCb;
      sWalker.xSelectCallback = renameColumnSelectCb;
      sWalker.u.pRename = &sCtx;

      if( sParse.pNewTable ){
        if( IsView(sParse.pNewTable) ){
          Select *pSelect = sParse.pNewTable->u.view.pSelect;
          pSelect->selFlags &= ~(u32)SF_View;
          sParse.rc = SQLITE_OK;
          sqlite3SelectPrep(&sParse, pSelect, 0);
          rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
          if( rc==SQLITE_OK ){
            sqlite3WalkSelect(&sWalker, pSelect);
          }
        }else{

#endif

  UNUSED_PARAMETER(NotUsed);

  if( zDb && zInput ){
    int rc;
    Parse sParse;
    u64 flags = db->flags;
    if( bNoDQS ) db->flags &= ~(SQLITE_DqsDML|SQLITE_DqsDDL);
    rc = renameParseSql(&sParse, zDb, db, zInput, bTemp);
    db->flags = flags;
    if( rc==SQLITE_OK ){
      if( isLegacy==0 && sParse.pNewTable && IsView(sParse.pNewTable) ){
        NameContext sNC;
        memset(&sNC, 0, sizeof(sNC));
        sNC.pParse = &sParse;
        sqlite3SelectPrep(&sParse, sParse.pNewTable->u.view.pSelect, &sNC);
        if( sParse.nErr ) rc = sParse.rc;

    sqlite3_result_error_nomem(context);
    return;
  }

  p->db = db;
  p->nEst = sqlite3_value_int64(argv[2]);
  p->nRow = 0;
  p->nLimit = sqlite3_value_int(argv[3]);
  p->nCol = nCol;
  p->nKeyCol = nKeyCol;
  p->nSkipAhead = 0;
  p->current.anDLt = (tRowcnt*)&p[1];

#ifdef SQLITE_ENABLE_STAT4
  p->current.anEq = &p->current.anDLt[nColUp];

  ** remove the entry from the db->aDb[] array. i.e. put everything back the
  ** way we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    db->init.iDb = 0;
    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( db->setlkFlags & SQLITE_SETLK_BLOCK_ON_CONNECT ){
      int val = 1;
      sqlite3_file *fd = sqlite3PagerFile(sqlite3BtreePager(pNew->pBt));
      sqlite3OsFileControlHint(fd, SQLITE_FCNTL_BLOCK_ON_CONNECT, &val);
    }
#endif
    if( !REOPEN_AS_MEMDB(db) ){
      rc = sqlite3Init(db, &zErrDyn);
    }
    sqlite3BtreeLeaveAll(db);
    assert( zErrDyn==0 || rc!=SQLITE_OK );
  }
  if( rc ){

/*
** Convert an table column number into a index column number.  That is,
** for the column iCol in the table (as defined by the CREATE TABLE statement)
** find the (first) offset of that column in index pIdx.  Or return -1
** if column iCol is not used in index pIdx.
*/
SQLITE_PRIVATE int sqlite3TableColumnToIndex(Index *pIdx, int iCol){
  int i;
  i16 iCol16;
  assert( iCol>=(-1) && iCol<=SQLITE_MAX_COLUMN );
  assert( pIdx->nColumn<=SQLITE_MAX_COLUMN+1 );
  iCol16 = iCol;
  for(i=0; i<pIdx->nColumn; i++){
    if( iCol16==pIdx->aiColumn[i] ){
      return i;
    }
  }
  return -1;
}

#ifndef SQLITE_OMIT_GENERATED_COLUMNS
/* Convert a storage column number into a table column number.
**

  return zStmt;
}

/*
** Resize an Index object to hold N columns total.  Return SQLITE_OK
** on success and SQLITE_NOMEM on an OOM error.
*/
static int resizeIndexObject(Parse *pParse, Index *pIdx, int N){
  char *zExtra;
  u64 nByte;
  sqlite3 *db;
  if( pIdx->nColumn>=N ) return SQLITE_OK;
  db = pParse->db;
  assert( N>0 );
  assert( N <= SQLITE_MAX_COLUMN*2 /* tag-20250221-1 */ );
  testcase( N==2*pParse->db->aLimit[SQLITE_LIMIT_COLUMN] );
  assert( pIdx->isResized==0 );
  nByte = (sizeof(char*) + sizeof(LogEst) + sizeof(i16) + 1)*(u64)N;
  zExtra = sqlite3DbMallocZero(db, nByte);
  if( zExtra==0 ) return SQLITE_NOMEM_BKPT;
  memcpy(zExtra, pIdx->azColl, sizeof(char*)*pIdx->nColumn);
  pIdx->azColl = (const char**)zExtra;
  zExtra += sizeof(char*)*N;
  memcpy(zExtra, pIdx->aiRowLogEst, sizeof(LogEst)*(pIdx->nKeyCol+1));
  pIdx->aiRowLogEst = (LogEst*)zExtra;
  zExtra += sizeof(LogEst)*N;
  memcpy(zExtra, pIdx->aiColumn, sizeof(i16)*pIdx->nColumn);
  pIdx->aiColumn = (i16*)zExtra;
  zExtra += sizeof(i16)*N;
  memcpy(zExtra, pIdx->aSortOrder, pIdx->nColumn);
  pIdx->aSortOrder = (u8*)zExtra;
  pIdx->nColumn = (u16)N;  /* See tag-20250221-1 above for proof of safety */
  pIdx->isResized = 1;
  return SQLITE_OK;
}

/*
** Estimate the total row width for a table.
*/

      }
    }
    if( n==0 ){
      /* This index is a superset of the primary key */
      pIdx->nColumn = pIdx->nKeyCol;
      continue;
    }
    if( resizeIndexObject(pParse, pIdx, pIdx->nKeyCol+n) ) return;
    for(i=0, j=pIdx->nKeyCol; i<nPk; i++){
      if( !isDupColumn(pIdx, pIdx->nKeyCol, pPk, i) ){
        testcase( hasColumn(pIdx->aiColumn, pIdx->nKeyCol, pPk->aiColumn[i]) );
        pIdx->aiColumn[j] = pPk->aiColumn[i];
        pIdx->azColl[j] = pPk->azColl[i];
        if( pPk->aSortOrder[i] ){
          /* See ticket https://sqlite.org/src/info/bba7b69f9849b5bf */
          pIdx->bAscKeyBug = 1;
        }
        j++;
      }
    }
    assert( pIdx->nColumn>=pIdx->nKeyCol+n );
    assert( pIdx->nColumn>=j );
  }

  /* Add all table columns to the PRIMARY KEY index
  */
  nExtra = 0;
  for(i=0; i<pTab->nCol; i++){
    if( !hasColumn(pPk->aiColumn, nPk, i)
     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ) nExtra++;
  }
  if( resizeIndexObject(pParse, pPk, nPk+nExtra) ) return;
  for(i=0, j=nPk; i<pTab->nCol; i++){
    if( !hasColumn(pPk->aiColumn, j, i)
     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0
    ){
      assert( j<pPk->nColumn );
      pPk->aiColumn[j] = i;
      pPk->azColl[j] = sqlite3StrBINARY;

    sqlite3ErrorMsg(pParse,
        "number of columns in foreign key does not match the number of "
        "columns in the referenced table");
    goto fk_end;
  }else{
    nCol = pFromCol->nExpr;
  }
  nByte = SZ_FKEY(nCol) + pTo->n + 1;
  if( pToCol ){
    for(i=0; i<pToCol->nExpr; i++){
      nByte += sqlite3Strlen30(pToCol->a[i].zEName) + 1;
    }
  }
  pFKey = sqlite3DbMallocZero(db, nByte );
  if( pFKey==0 ){

  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
  if( !pIndex->bAscKeyBug ){
    /* This OP_SeekEnd opcode makes index insert for a REINDEX go much
    ** faster by avoiding unnecessary seeks.  But the optimization does
    ** not work for UNIQUE constraint indexes on WITHOUT ROWID tables
    ** with DESC primary keys, since those indexes have there keys in
    ** a different order from the main table.
    ** See ticket: https://sqlite.org/src/info/bba7b69f9849b5bf
    */
    sqlite3VdbeAddOp1(v, OP_SeekEnd, iIdx);
  }
  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);

**
** Increase the allocation size to provide an extra nExtra bytes
** of 8-byte aligned space after the Index object and return a
** pointer to this extra space in *ppExtra.
*/
SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(
  sqlite3 *db,         /* Database connection */
  int nCol,            /* Total number of columns in the index */
  int nExtra,          /* Number of bytes of extra space to alloc */
  char **ppExtra       /* Pointer to the "extra" space */
){
  Index *p;            /* Allocated index object */
  i64 nByte;           /* Bytes of space for Index object + arrays */

  assert( nCol <= 2*db->aLimit[SQLITE_LIMIT_COLUMN] );
  nByte = ROUND8(sizeof(Index)) +              /* Index structure  */
          ROUND8(sizeof(char*)*nCol) +         /* Index.azColl     */
          ROUND8(sizeof(LogEst)*(nCol+1) +     /* Index.aiRowLogEst   */
                 sizeof(i16)*nCol +            /* Index.aiColumn   */
                 sizeof(u8)*nCol);             /* Index.aSortOrder */
  p = sqlite3DbMallocZero(db, nByte + nExtra);
  if( p ){
    char *pExtra = ((char*)p)+ROUND8(sizeof(Index));
    p->azColl = (const char**)pExtra; pExtra += ROUND8(sizeof(char*)*nCol);
    p->aiRowLogEst = (LogEst*)pExtra; pExtra += sizeof(LogEst)*(nCol+1);
    p->aiColumn = (i16*)pExtra;       pExtra += sizeof(i16)*nCol;
    p->aSortOrder = (u8*)pExtra;
    assert( nCol>0 );
    p->nColumn = (u16)nCol;
    p->nKeyCol = (u16)(nCol - 1);
    *ppExtra = ((char*)p) + nByte;
  }
  return p;
}

/*
** If expression list pList contains an expression that was parsed with

      pIndex->uniqNotNull = 0;
      pIndex->bHasExpr = 1;
    }else{
      j = pCExpr->iColumn;
      assert( j<=0x7fff );
      if( j<0 ){
        j = pTab->iPKey;
        pIndex->bIdxRowid = 1;
      }else{
        if( pTab->aCol[j].notNull==0 ){
          pIndex->uniqNotNull = 0;
        }
        if( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL ){
          pIndex->bHasVCol = 1;
          pIndex->bHasExpr = 1;

**
** A new IdList is returned, or NULL if malloc() fails.
*/
SQLITE_PRIVATE IdList *sqlite3IdListAppend(Parse *pParse, IdList *pList, Token *pToken){
  sqlite3 *db = pParse->db;
  int i;
  if( pList==0 ){
    pList = sqlite3DbMallocZero(db, SZ_IDLIST(1));
    if( pList==0 ) return 0;
  }else{
    IdList *pNew;
    pNew = sqlite3DbRealloc(db, pList, SZ_IDLIST(pList->nId+1));

    if( pNew==0 ){
      sqlite3IdListDelete(db, pList);
      return 0;
    }
    pList = pNew;
  }
  i = pList->nId++;

    if( pSrc->nSrc+nExtra>=SQLITE_MAX_SRCLIST ){
      sqlite3ErrorMsg(pParse, "too many FROM clause terms, max: %d",
                      SQLITE_MAX_SRCLIST);
      return 0;
    }
    if( nAlloc>SQLITE_MAX_SRCLIST ) nAlloc = SQLITE_MAX_SRCLIST;
    pNew = sqlite3DbRealloc(db, pSrc, SZ_SRCLIST(nAlloc));

    if( pNew==0 ){
      assert( db->mallocFailed );
      return 0;
    }
    pSrc = pNew;
    pSrc->nAlloc = nAlloc;
  }

  SrcItem *pItem;
  sqlite3 *db;
  assert( pDatabase==0 || pTable!=0 );  /* Cannot have C without B */
  assert( pParse!=0 );
  assert( pParse->db!=0 );
  db = pParse->db;
  if( pList==0 ){
    pList = sqlite3DbMallocRawNN(pParse->db, SZ_SRCLIST(1));
    if( pList==0 ) return 0;
    pList->nAlloc = 1;
    pList->nSrc = 1;
    memset(&pList->a[0], 0, sizeof(pList->a[0]));
    pList->a[0].iCursor = -1;
  }else{
    SrcList *pNew = sqlite3SrcListEnlarge(pParse, pList, 1, pList->nSrc);

      if( sqlite3StrICmp(zName, pWith->a[i].zName)==0 ){
        sqlite3ErrorMsg(pParse, "duplicate WITH table name: %s", zName);
      }
    }
  }

  if( pWith ){

    pNew = sqlite3DbRealloc(db, pWith, SZ_WITH(pWith->nCte+1));
  }else{
    pNew = sqlite3DbMallocZero(db, SZ_WITH(1));
  }
  assert( (pNew!=0 && zName!=0) || db->mallocFailed );

  if( db->mallocFailed ){
    sqlite3CteDelete(db, pCte);
    pNew = pWith;
  }else{

  '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};

/*
** Append to pStr text that is the SQL literal representation of the
** value contained in pValue.
*/
SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum *pStr, sqlite3_value *pValue, int bEscape){
  /* As currently implemented, the string must be initially empty.
  ** we might relax this requirement in the future, but that will
  ** require enhancements to the implementation. */
  assert( pStr!=0 && pStr->nChar==0 );

  switch( sqlite3_value_type(pValue) ){
    case SQLITE_FLOAT: {

        zText[1] = '\'';
        pStr->nChar = nBlob*2 + 3;
      }
      break;
    }
    case SQLITE_TEXT: {
      const unsigned char *zArg = sqlite3_value_text(pValue);
      sqlite3_str_appendf(pStr, bEscape ? "%#Q" : "%Q", zArg);
      break;
    }
    default: {
      assert( sqlite3_value_type(pValue)==SQLITE_NULL );
      sqlite3_str_append(pStr, "NULL", 4);
      break;
    }
  }
}

/*
** Return true if z[] begins with N hexadecimal digits, and write
** a decoding of those digits into *pVal.  Or return false if any
** one of the first N characters in z[] is not a hexadecimal digit.
*/
static int isNHex(const char *z, int N, u32 *pVal){
  int i;
  int v = 0;
  for(i=0; i<N; i++){
    if( !sqlite3Isxdigit(z[i]) ) return 0;
    v = (v<<4) + sqlite3HexToInt(z[i]);
  }
  *pVal = v;
  return 1;
}

/*
** Implementation of the UNISTR() function.
**
** This is intended to be a work-alike of the UNISTR() function in
** PostgreSQL.  Quoting from the PG documentation (PostgreSQL 17 -
** scraped on 2025-02-22):
**
**    Evaluate escaped Unicode characters in the argument. Unicode
**    characters can be specified as \XXXX (4 hexadecimal digits),
**    \+XXXXXX (6 hexadecimal digits), \uXXXX (4 hexadecimal digits),
**    or \UXXXXXXXX (8 hexadecimal digits). To specify a backslash,
**    write two backslashes. All other characters are taken literally.
*/
static void unistrFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  char *zOut;
  const char *zIn;
  int nIn;
  int i, j, n;
  u32 v;

  assert( argc==1 );
  UNUSED_PARAMETER( argc );
  zIn = (const char*)sqlite3_value_text(argv[0]);
  if( zIn==0 ) return;
  nIn = sqlite3_value_bytes(argv[0]);
  zOut = sqlite3_malloc64(nIn+1);
  if( zOut==0 ){
    sqlite3_result_error_nomem(context);
    return;
  }
  i = j = 0;
  while( i<nIn ){
    char *z = strchr(&zIn[i],'\\');
    if( z==0 ){
      n = nIn - i;
      memmove(&zOut[j], &zIn[i], n);
      j += n;
      break;
    }
    n = z - &zIn[i];
    if( n>0 ){
      memmove(&zOut[j], &zIn[i], n);
      j += n;
      i += n;
    }
    if( zIn[i+1]=='\\' ){
      i += 2;
      zOut[j++] = '\\';
    }else if( sqlite3Isxdigit(zIn[i+1]) ){
      if( !isNHex(&zIn[i+1], 4, &v) ) goto unistr_error;
      i += 5;
      j += sqlite3AppendOneUtf8Character(&zOut[j], v);
    }else if( zIn[i+1]=='+' ){
      if( !isNHex(&zIn[i+2], 6, &v) ) goto unistr_error;
      i += 8;
      j += sqlite3AppendOneUtf8Character(&zOut[j], v);
    }else if( zIn[i+1]=='u' ){
      if( !isNHex(&zIn[i+2], 4, &v) ) goto unistr_error;
      i += 6;
      j += sqlite3AppendOneUtf8Character(&zOut[j], v);
    }else if( zIn[i+1]=='U' ){
      if( !isNHex(&zIn[i+2], 8, &v) ) goto unistr_error;
      i += 10;
      j += sqlite3AppendOneUtf8Character(&zOut[j], v);
    }else{
      goto unistr_error;
    }
  }
  zOut[j] = 0;
  sqlite3_result_text64(context, zOut, j, sqlite3_free, SQLITE_UTF8);
  return;

unistr_error:
  sqlite3_free(zOut);
  sqlite3_result_error(context, "invalid Unicode escape", -1);
  return;
}


/*
** Implementation of the QUOTE() function.
**
** The quote(X) function returns the text of an SQL literal which is the
** value of its argument suitable for inclusion into an SQL statement.
** Strings are surrounded by single-quotes with escapes on interior quotes
** as needed. BLOBs are encoded as hexadecimal literals. Strings with
** embedded NUL characters cannot be represented as string literals in SQL
** and hence the returned string literal is truncated prior to the first NUL.
**
** If sqlite3_user_data() is non-zero, then the UNISTR_QUOTE() function is
** implemented instead.  The difference is that UNISTR_QUOTE() uses the
** UNISTR() function to escape control characters.
*/
static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  sqlite3_str str;
  sqlite3 *db = sqlite3_context_db_handle(context);
  assert( argc==1 );
  UNUSED_PARAMETER(argc);
  sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
  sqlite3QuoteValue(&str,argv[0],SQLITE_PTR_TO_INT(sqlite3_user_data(context)));
  sqlite3_result_text(context, sqlite3StrAccumFinish(&str), str.nChar,
                      SQLITE_DYNAMIC);
  if( str.accError!=SQLITE_OK ){
    sqlite3_result_null(context);
    sqlite3_result_error_code(context, str.accError);
  }
}

/*
** Routines used to compute the sum, average, and total.
**
** The SUM() function follows the (broken) SQL standard which means
** that it returns NULL if it sums over no inputs.  TOTAL returns
** 0.0 in that case.  In addition, TOTAL always returns a float where
** SUM might return an integer if it never encounters a floating point
** value.  TOTAL never fails, but SUM might throw an exception if
** it overflows an integer.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  SumCtx *p;
  int type;
  assert( argc==1 );
  UNUSED_PARAMETER(argc);

    INLINE_FUNC(ifnull,          2, INLINEFUNC_coalesce, 0 ),
    VFUNCTION(random,            0, 0, 0, randomFunc       ),
    VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),
    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
    DFUNCTION(sqlite_version,    0, 0, 0, versionFunc      ),
    DFUNCTION(sqlite_source_id,  0, 0, 0, sourceidFunc     ),
    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
    FUNCTION(unistr,             1, 0, 0, unistrFunc       ),
    FUNCTION(quote,              1, 0, 0, quoteFunc        ),
    FUNCTION(unistr_quote,       1, 1, 0, quoteFunc        ),
    VFUNCTION(last_insert_rowid, 0, 0, 0, last_insert_rowid),
    VFUNCTION(changes,           0, 0, 0, changes          ),
    VFUNCTION(total_changes,     0, 0, 0, total_changes    ),
    FUNCTION(replace,            3, 0, 0, replaceFunc      ),
    FUNCTION(zeroblob,           1, 0, 0, zeroblobFunc     ),
    FUNCTION(substr,             2, 0, 0, substrFunc       ),
    FUNCTION(substr,             3, 0, 0, substrFunc       ),

      sqlite3MultiValuesEnd(pParse, pLeft);
      f = SF_Values;
    }else if( pLeft->pPrior ){
      /* In this case set the SF_MultiValue flag only if it was set on pLeft */
      f = (f & pLeft->selFlags);
    }
    pSelect = sqlite3SelectNew(pParse, pRow, 0, 0, 0, 0, 0, f, 0);
    pLeft->selFlags &= ~(u32)SF_MultiValue;
    if( pSelect ){
      pSelect->op = TK_ALL;
      pSelect->pPrior = pLeft;
      pLeft = pSelect;
    }
  }else{
    SrcItem *p = 0;               /* SrcItem that reads from co-routine */

  **
  ** OE_Fail and OE_Ignore must happen before any changes are made.
  ** OE_Update guarantees that only a single row will change, so it
  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
  ** could happen in any order, but they are grouped up front for
  ** convenience.
  **
  ** 2018-08-14: Ticket https://sqlite.org/src/info/908f001483982c43
  ** The order of constraints used to have OE_Update as (2) and OE_Abort
  ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
  ** constraint before any others, so it had to be moved.
  **
  ** Constraint checking code is generated in this order:
  **   (A)  The rowid constraint
  **   (B)  Unique index constraints that do not have OE_Replace as their

  /*   9 */ "name",
  /*  10 */ "type",
  /*  11 */ "notnull",
  /*  12 */ "dflt_value",
  /*  13 */ "pk",
  /*  14 */ "hidden",
                           /* table_info reuses 8 */
  /*  15 */ "name",        /* Used by: function_list */
  /*  16 */ "builtin",
  /*  17 */ "type",
  /*  18 */ "enc",
  /*  19 */ "narg",
  /*  20 */ "flags",
  /*  21 */ "schema",      /* Used by: table_list */
  /*  22 */ "name",
  /*  23 */ "type",
  /*  24 */ "ncol",
  /*  25 */ "wr",
  /*  26 */ "strict",
  /*  27 */ "seqno",       /* Used by: index_xinfo */
  /*  28 */ "cid",
  /*  29 */ "name",
  /*  30 */ "desc",
  /*  31 */ "coll",
  /*  32 */ "key",
  /*  33 */ "seq",         /* Used by: index_list */
  /*  34 */ "name",
  /*  35 */ "unique",
  /*  36 */ "origin",
  /*  37 */ "partial",
  /*  38 */ "tbl",         /* Used by: stats */
  /*  39 */ "idx",
  /*  40 */ "wdth",
  /*  41 */ "hght",
  /*  42 */ "flgs",
  /*  43 */ "table",       /* Used by: foreign_key_check */
  /*  44 */ "rowid",
  /*  45 */ "parent",
  /*  46 */ "fkid",

  /*  47 */ "busy",        /* Used by: wal_checkpoint */
  /*  48 */ "log",
  /*  49 */ "checkpointed",
  /*  50 */ "seq",         /* Used by: database_list */
  /*  51 */ "name",
  /*  52 */ "file",
                           /* index_info reuses 27 */
  /*  53 */ "database",    /* Used by: lock_status */
  /*  54 */ "status",
                           /* collation_list reuses 33 */
  /*  55 */ "cache_size",  /* Used by: default_cache_size */
                           /* module_list pragma_list reuses 9 */
  /*  56 */ "timeout",     /* Used by: busy_timeout */
};

/* Definitions of all built-in pragmas */
typedef struct PragmaName {

  /* ColNames:  */ 0, 0,
  /* iArg:      */ SQLITE_CkptFullFSync },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
 {/* zName:     */ "collation_list",
  /* ePragTyp:  */ PragTyp_COLLATION_LIST,
  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 33, 2,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)
 {/* zName:     */ "compile_options",
  /* ePragTyp:  */ PragTyp_COMPILE_OPTIONS,
  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 0, 0,

  /* ColNames:  */ 0, 0,
  /* iArg:      */ BTREE_DATA_VERSION },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
 {/* zName:     */ "database_list",
  /* ePragTyp:  */ PragTyp_DATABASE_LIST,
  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 50, 3,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
 {/* zName:     */ "default_cache_size",
  /* ePragTyp:  */ PragTyp_DEFAULT_CACHE_SIZE,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
  /* ColNames:  */ 55, 1,

  /* iArg:      */ SQLITE_FullFSync },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
 {/* zName:     */ "function_list",
  /* ePragTyp:  */ PragTyp_FUNCTION_LIST,
  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 15, 6,
  /* iArg:      */ 0 },
#endif
#endif
 {/* zName:     */ "hard_heap_limit",
  /* ePragTyp:  */ PragTyp_HARD_HEAP_LIMIT,
  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 0, 0,

  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
 {/* zName:     */ "index_info",
  /* ePragTyp:  */ PragTyp_INDEX_INFO,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 27, 3,
  /* iArg:      */ 0 },
 {/* zName:     */ "index_list",
  /* ePragTyp:  */ PragTyp_INDEX_LIST,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 33, 5,
  /* iArg:      */ 0 },
 {/* zName:     */ "index_xinfo",
  /* ePragTyp:  */ PragTyp_INDEX_INFO,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 27, 6,
  /* iArg:      */ 1 },
#endif
#if !defined(SQLITE_OMIT_INTEGRITY_CHECK)
 {/* zName:     */ "integrity_check",
  /* ePragTyp:  */ PragTyp_INTEGRITY_CHECK,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 0, 0,

  /* iArg:      */ SQLITE_SqlTrace },
#endif
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) && defined(SQLITE_DEBUG)
 {/* zName:     */ "stats",
  /* ePragTyp:  */ PragTyp_STATS,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
  /* ColNames:  */ 38, 5,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
 {/* zName:     */ "synchronous",
  /* ePragTyp:  */ PragTyp_SYNCHRONOUS,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
 {/* zName:     */ "table_info",
  /* ePragTyp:  */ PragTyp_TABLE_INFO,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 8, 6,
  /* iArg:      */ 0 },
 {/* zName:     */ "table_list",
  /* ePragTyp:  */ PragTyp_TABLE_LIST,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1,
  /* ColNames:  */ 21, 6,
  /* iArg:      */ 0 },
 {/* zName:     */ "table_xinfo",
  /* ePragTyp:  */ PragTyp_TABLE_INFO,
  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
  /* ColNames:  */ 8, 7,
  /* iArg:      */ 1 },
#endif

  /* ePragTyp:  */ PragTyp_WAL_AUTOCHECKPOINT,
  /* ePragFlg:  */ 0,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 {/* zName:     */ "wal_checkpoint",
  /* ePragTyp:  */ PragTyp_WAL_CHECKPOINT,
  /* ePragFlg:  */ PragFlg_NeedSchema,
  /* ColNames:  */ 47, 3,
  /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
 {/* zName:     */ "writable_schema",
  /* ePragTyp:  */ PragTyp_FLAG,
  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
  /* ColNames:  */ 0, 0,

/*
** When the 0x10 bit of PRAGMA optimize is set, any ANALYZE commands
** will be run with an analysis_limit set to the lessor of the value of
** the following macro or to the actual analysis_limit if it is non-zero,
** in order to prevent PRAGMA optimize from running for too long.
**
** The value of 2000 is chosen empirically so that the worst-case run-time
** for PRAGMA optimize does not exceed 100 milliseconds against a variety
** of test databases on a RaspberryPI-4 compiled using -Os and without
** -DSQLITE_DEBUG.  Of course, your mileage may vary.  For the purpose of
** this paragraph, "worst-case" means that ANALYZE ends up being
** run on every table in the database.  The worst case typically only
** happens if PRAGMA optimize is run on a database file for which ANALYZE
** has not been previously run and the 0x10000 flag is included so that

  pNew->selFlags = selFlags;
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selId = ++pParse->nSelect;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->nSelectRow = 0;
  if( pSrc==0 ) pSrc = sqlite3DbMallocZero(pParse->db, SZ_SRCLIST_1);
  pNew->pSrc = pSrc;
  pNew->pWhere = pWhere;
  pNew->pGroupBy = pGroupBy;
  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->pPrior = 0;
  pNew->pNext = 0;

}

/*
** Allocate a KeyInfo object sufficient for an index of N key columns and
** X extra columns.
*/
SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){
  int nExtra = (N+X)*(sizeof(CollSeq*)+1);
  KeyInfo *p = sqlite3DbMallocRawNN(db, SZ_KEYINFO(0) + nExtra);
  if( p ){
    p->aSortFlags = (u8*)&p->aColl[N+X];
    p->nKeyField = (u16)N;
    p->nAllField = (u16)(N+X);
    p->enc = ENC(db);
    p->db = db;
    p->nRef = 1;
    memset(p->aColl, 0, nExtra);
  }else{
    return (KeyInfo*)sqlite3OomFault(db);
  }
  return p;
}

/*

    }
    sqlite3KeyInfoUnref(pKeyInfo);
  }

multi_select_end:
  pDest->iSdst = dest.iSdst;
  pDest->nSdst = dest.nSdst;
  pDest->iSDParm2 = dest.iSDParm2;
  if( pDelete ){
    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pDelete);
  }
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

    assert( pE2->op==TK_COLUMN );
    if( pE2->iTable==pColumn->iTable
     && pE2->iColumn==pColumn->iColumn
    ){
      return;  /* Already present.  Return without doing anything. */
    }
  }
  assert( SQLITE_AFF_NONE<SQLITE_AFF_BLOB );
  if( sqlite3ExprAffinity(pColumn)<=SQLITE_AFF_BLOB ){
    pConst->bHasAffBlob = 1;
  }

  pConst->nConst++;
  pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr,
                         pConst->nConst*2*sizeof(Expr*));
  if( pConst->apExpr==0 ){

    return WRC_Continue;
  }
  for(i=0; i<pConst->nConst; i++){
    Expr *pColumn = pConst->apExpr[i*2];
    if( pColumn==pExpr ) continue;
    if( pColumn->iTable!=pExpr->iTable ) continue;
    if( pColumn->iColumn!=pExpr->iColumn ) continue;
    assert( SQLITE_AFF_NONE<SQLITE_AFF_BLOB );
    if( bIgnoreAffBlob && sqlite3ExprAffinity(pColumn)<=SQLITE_AFF_BLOB ){
      break;
    }
    /* A match is found.  Add the EP_FixedCol property */
    pConst->nChng++;
    ExprClearProperty(pExpr, EP_Leaf);
    ExprSetProperty(pExpr, EP_FixedCol);
    assert( pExpr->pLeft==0 );

**    SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2)
**     ORDER BY ... COLLATE ...
**
** This transformation is necessary because the multiSelectOrderBy() routine
** above that generates the code for a compound SELECT with an ORDER BY clause
** uses a merge algorithm that requires the same collating sequence on the
** result columns as on the ORDER BY clause.  See ticket
** http://sqlite.org/src/info/6709574d2a
**
** This transformation is only needed for EXCEPT, INTERSECT, and UNION.
** The UNION ALL operator works fine with multiSelectOrderBy() even when
** there are COLLATE terms in the ORDER BY.
*/
static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
  int i;

  pNew->pOrderBy = 0;
  p->pPrior = 0;
  p->pNext = 0;
  p->pWith = 0;
#ifndef SQLITE_OMIT_WINDOWFUNC
  p->pWinDefn = 0;
#endif
  p->selFlags &= ~(u32)SF_Compound;
  assert( (p->selFlags & SF_Converted)==0 );
  p->selFlags |= SF_Converted;
  assert( pNew->pPrior!=0 );
  pNew->pPrior->pNext = pNew;
  pNew->pLimit = 0;
  return WRC_Continue;
}

    /* Renumber selId because it has been copied from a view */
    p->selId = ++pParse->nSelect;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  if( pParse->pWith && (p->selFlags & SF_View) ){
    if( p->pWith==0 ){
      p->pWith = (With*)sqlite3DbMallocZero(db, SZ_WITH(1) );
      if( p->pWith==0 ){
        return WRC_Abort;
      }
    }
    p->pWith->bView = 1;
  }
  sqlite3WithPush(pParse, p->pWith, 0);

** The transformation only works if all of the following are true:
**
**   *  The subquery is a UNION ALL of two or more terms
**   *  The subquery does not have a LIMIT clause
**   *  There is no WHERE or GROUP BY or HAVING clauses on the subqueries
**   *  The outer query is a simple count(*) with no WHERE clause or other
**      extraneous syntax.
**   *  None of the subqueries are DISTINCT (forumpost/a860f5fb2e 2025-03-10)
**
** Return TRUE if the optimization is undertaken.
*/
static int countOfViewOptimization(Parse *pParse, Select *p){
  Select *pSub, *pPrior;
  Expr *pExpr;
  Expr *pCount;

  pSub = pFrom->u4.pSubq->pSelect;
  if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
  if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
  do{
    if( pSub->op!=TK_ALL && pSub->pPrior ) return 0;  /* Must be UNION ALL */
    if( pSub->pWhere ) return 0;                      /* No WHERE clause */
    if( pSub->pLimit ) return 0;                      /* No LIMIT clause */
    if( pSub->selFlags & (SF_Aggregate|SF_Distinct) ){
       testcase( pSub->selFlags & SF_Aggregate );
       testcase( pSub->selFlags & SF_Distinct );
       return 0;     /* Not an aggregate nor DISTINCT */
    }
    assert( pSub->pHaving==0 );  /* Due to the previous */
    pSub = pSub->pPrior;                              /* Repeat over compound */
  }while( pSub );

  /* If we reach this point then it is OK to perform the transformation */

  db = pParse->db;
  pCount = pExpr;
  pExpr = 0;
  pSub = sqlite3SubqueryDetach(db, pFrom);
  sqlite3SrcListDelete(db, p->pSrc);
  p->pSrc = sqlite3DbMallocZero(pParse->db, SZ_SRCLIST_1);
  while( pSub ){
    Expr *pTerm;
    pPrior = pSub->pPrior;
    pSub->pPrior = 0;
    pSub->pNext = 0;
    pSub->selFlags |= SF_Aggregate;
    pSub->selFlags &= ~(u32)SF_Compound;
    pSub->nSelectRow = 0;
    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pSub->pEList);
    pTerm = pPrior ? sqlite3ExprDup(db, pCount, 0) : pCount;
    pSub->pEList = sqlite3ExprListAppend(pParse, 0, pTerm);
    pTerm = sqlite3PExpr(pParse, TK_SELECT, 0, 0);
    sqlite3PExprAddSelect(pParse, pTerm, pSub);
    if( pExpr==0 ){
      pExpr = pTerm;
    }else{
      pExpr = sqlite3PExpr(pParse, TK_PLUS, pTerm, pExpr);
    }
    pSub = pPrior;
  }
  p->pEList->a[0].pExpr = pExpr;
  p->selFlags &= ~(u32)SF_Aggregate;

#if TREETRACE_ENABLED
  if( sqlite3TreeTrace & 0x200 ){
    TREETRACE(0x200,pParse,p,("After count-of-view optimization:\n"));
    sqlite3TreeViewSelect(0, p, 0);
  }
#endif

      }
#endif
      sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric,
                              p->pOrderBy);
      testcase( pParse->earlyCleanup );
      p->pOrderBy = 0;
    }
    p->selFlags &= ~(u32)SF_Distinct;
    p->selFlags |= SF_NoopOrderBy;
  }
  sqlite3SelectPrep(pParse, p, 0);
  if( pParse->nErr ){
    goto select_end;
  }
  assert( db->mallocFailed==0 );

      goto select_end;
    }

    /* Clear the SF_UFSrcCheck flag. The check has already been performed,
    ** and leaving this flag set can cause errors if a compound sub-query
    ** in p->pSrc is flattened into this query and this function called
    ** again as part of compound SELECT processing.  */
    p->selFlags &= ~(u32)SF_UFSrcCheck;
  }

  if( pDest->eDest==SRT_Output ){
    sqlite3GenerateColumnNames(pParse, p);
  }

#ifndef SQLITE_OMIT_WINDOWFUNC

  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct
   && sqlite3ExprListCompare(sSort.pOrderBy, pEList, -1)==0
   && OptimizationEnabled(db, SQLITE_GroupByOrder)
#ifndef SQLITE_OMIT_WINDOWFUNC
   && p->pWin==0
#endif
  ){
    p->selFlags &= ~(u32)SF_Distinct;
    pGroupBy = p->pGroupBy = sqlite3ExprListDup(db, pEList, 0);
    if( pGroupBy ){
      for(i=0; i<pGroupBy->nExpr; i++){
        pGroupBy->a[i].u.x.iOrderByCol = i+1;
      }
    }
    p->selFlags |= SF_Aggregate;