sqllogictest

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.50.0.  By combining all the individual C code files into this
** single large file, the entire code can be compiled as a single translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% or more are commonly seen when SQLite is compiled as a single
** translation unit.
**
** This file is all you need to compile SQLite.  To use SQLite in other
** programs, you need this file and the "sqlite3.h" header file that defines
** the programming interface to the SQLite library.  (If you do not have
** the "sqlite3.h" header file at hand, you will find a copy embedded within
** the text of this file.  Search for "Begin file sqlite3.h" to find the start
** of the embedded sqlite3.h header file.) Additional code files may be needed
** if you want a wrapper to interface SQLite with your choice of programming
** language. The code for the "sqlite3" command-line shell is also in a
** separate file. This file contains only code for the core SQLite library.
**
** The content in this amalgamation comes from Fossil check-in
** ba8184d132a935aa1980fbfb61ff308b93d4 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      "2025-05-19 14:50:36 ba8184d132a935aa1980fbfb61ff308b93d433d559db4968f9014f7653ac9c6e"

/*
** 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

** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
** the entire mutexing subsystem is omitted from the build and hence calls to
** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
** return [SQLITE_ERROR].</dd>
**
** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
** the default size of [lookaside memory] on each [database connection].
** The first argument is the
** size of each lookaside buffer slot ("sz") and the second is the number of
** slots allocated to each database connection ("cnt").)^
** ^(SQLITE_CONFIG_LOOKASIDE sets the <i>default</i> lookaside size.
** The [SQLITE_DBCONFIG_LOOKASIDE] option to [sqlite3_db_config()] can
** be used to change the lookaside configuration on individual connections.)^
** The [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to change the
** default lookaside configuration at compile-time.
** </dd>
**
** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
** the interface to a custom page cache implementation.)^
** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
**

#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */

/*
** CAPI3REF: Database Connection Configuration Options
**
** These constants are the available integer configuration options that
** can be passed as the second parameter to the [sqlite3_db_config()] interface.
**
** The [sqlite3_db_config()] interface is a var-args functions.  It takes a
** variable number of parameters, though always at least two.  The number of
** parameters passed into sqlite3_db_config() depends on which of these
** constants is given as the second parameter.  This documentation page
** refers to parameters beyond the second as "arguments".  Thus, when this
** page says "the N-th argument" it means "the N-th parameter past the
** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
**
** New configuration options may be added in future releases of SQLite.
** Existing configuration options might be discontinued.  Applications
** should check the return code from [sqlite3_db_config()] to make sure that
** the call worked.  ^The [sqlite3_db_config()] interface will return a
** non-zero [error code] if a discontinued or unsupported configuration option
** is invoked.
**
** <dl>
** [[SQLITE_DBCONFIG_LOOKASIDE]]
** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
** configuration of the [lookaside memory allocator] within a database
** connection.
** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
** in the [DBCONFIG arguments|usual format].
** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
** should have a total of five parameters.
** <ol>
** <li><p>The first argument ("buf") is a
** pointer to a memory buffer to use for lookaside memory.

** The first argument may be NULL in which case SQLite will allocate the
** lookaside buffer itself using [sqlite3_malloc()].
** <li><P>The second argument ("sz") is the
** size of each lookaside buffer slot.  Lookaside is disabled if "sz"
** is less than 8.  The "sz" argument should be a multiple of 8 less than
** 65536.  If "sz" does not meet this constraint, it is reduced in size until
** it does.
** <li><p>The third argument ("cnt") is the number of slots. Lookaside is disabled
** if "cnt"is less than 1.  The "cnt" value will be reduced, if necessary, so
** that the product of "sz" and "cnt" does not exceed 2,147,418,112.  The "cnt"
** parameter is usually chosen so that the product of "sz" and "cnt" is less
** than 1,000,000.
** </ol>
** <p>If the "buf" argument is not NULL, then it must
** point to a memory buffer with a size that is greater than
** or equal to the product of "sz" and "cnt".
** The buffer must be aligned to an 8-byte boundary.

** The lookaside memory
** configuration for a database connection can only be changed when that
** connection is not currently using lookaside memory, or in other words

** when the value returned by [SQLITE_DBSTATUS_LOOKASIDE_USED] is zero.
** Any attempt to change the lookaside memory configuration when lookaside
** memory is in use leaves the configuration unchanged and returns
** [SQLITE_BUSY].
** If the "buf" argument is NULL and an attempt
** to allocate memory based on "sz" and "cnt" fails, then
** lookaside is silently disabled.
** <p>
** The [SQLITE_CONFIG_LOOKASIDE] configuration option can be used to set the
** default lookaside configuration at initialization.  The
** [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to set the default lookaside
** configuration at compile-time.  Typical values for lookaside are 1200 for
** "sz" and 40 to 100 for "cnt".
** </dd>
**
** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
** <dd> ^This option is used to enable or disable the enforcement of
** [foreign key constraints].  This is the same setting that is
** enabled or disabled by the [PRAGMA foreign_keys] statement.
** The first argument is an integer which is 0 to disable FK enforcement,

** be a NULL pointer, in which case the new setting is not reported back.
** </dd>
**
** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
** <dd> ^This option is used to change the name of the "main" database
** schema.  This option does not follow the
** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
** This option takes exactly one additional argument so that the
** [sqlite3_db_config()] call has a total of three parameters.  The
** extra argument must be a pointer to a constant UTF8 string which
** will become the new schema name in place of "main".  ^SQLite does
** not make a copy of the new main schema name string, so the application
** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
** is unchanged until after the database connection closes.
** </dd>
**
** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
** <dd> Usually, when a database in [WAL mode] is closed or detached from a
** database handle, SQLite checks if if there are other connections to the
** same database, and if there are no other database connection (if the
** connection being closed is the last open connection to the database),
** then SQLite performs a [checkpoint] before closing the connection and
** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
** be used to override that behavior. The first argument passed to this
** operation (the third parameter to [sqlite3_db_config()]) is an integer
** which is positive to disable checkpoints-on-close, or zero (the default)
** to enable them, and negative to leave the setting unchanged.
** The second argument (the fourth parameter) is a pointer to an integer
** into which is written 0 or 1 to indicate whether checkpoints-on-close
** have been disabled - 0 if they are not disabled, 1 if they are.
** </dd>
**
** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
** the [query planner stability guarantee] (QPSG).  When the QPSG is active,

** comments are allowed in SQL text after processing the first argument.
** </dd>
**
** </dl>
**
** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
**
** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
** overall call to [sqlite3_db_config()] has a total of four parameters.
** The first argument (the third parameter to sqlite3_db_config()) is a integer.
** The second argument is a pointer to an integer.  If the first argument is 1,
** then the option becomes enabled.  If the first integer argument is 0, then the
** option is disabled.  If the first argument is -1, then the option setting
** is unchanged.  The second argument, the pointer to an integer, may be NULL.
** If the second argument is not NULL, then a value of 0 or 1 is written into
** the integer to which the second argument points, depending on whether the
** setting is disabled or enabled after applying any changes specified by
** the first argument.
**

** 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().
*/

/*
** CAPI3REF: Flags for sqlite3changeset_start_v2
**
** The following flags may passed via the 4th parameter to
** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
**
** <dt>SQLITE_CHANGESETSTART_INVERT <dd>
**   Invert the changeset while iterating through it. This is equivalent to
**   inverting a changeset using sqlite3changeset_invert() before applying it.
**   It is an error to specify this flag with a patchset.
*/
#define SQLITE_CHANGESETSTART_INVERT        0x0002

  int nA,                         /* Number of bytes in buffer pA */
  void *pA,                       /* Pointer to buffer containing changeset A */
  int nB,                         /* Number of bytes in buffer pB */
  void *pB,                       /* Pointer to buffer containing changeset B */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: Buffer containing output changeset */
);














/*
** CAPI3REF: Changegroup Handle
**
** A changegroup is an object used to combine two or more
** [changesets] or [patchsets]
*/

**    * 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

** Again, this structure is intended to be opaque, but it can't really
** be opaque because it is used by macros.
*/
struct HashElem {
  HashElem *next, *prev;       /* Next and previous elements in the table */
  void *data;                  /* Data associated with this element */
  const char *pKey;            /* Key associated with this element */
  unsigned int h;              /* hash for pKey */
};

/*
** Access routines.  To delete, insert a NULL pointer.
*/
SQLITE_PRIVATE void sqlite3HashInit(Hash*);
SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const char *pKey, void *pData);

#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))

typedef sqlite_int64 i64;          /* 8-byte signed integer */
typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */
typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
typedef INT16_TYPE i16;            /* 2-byte signed integer */
typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
typedef INT8_TYPE i8;              /* 1-byte signed integer */

/* A bitfield type for use inside of structures.  Always follow with :N where
** N is the number of bits.
*/
typedef unsigned bft;  /* Bit Field Type */

/*
** SQLITE_MAX_U32 is a u64 constant that is the maximum u64 value
** that can be stored in a u32 without loss of data.  The value
** is 0x00000000ffffffff.  But because of quirks of some compilers, we
** have to specify the value in the less intuitive manner shown:
*/

** These macros are designed to work correctly on both 32-bit and 64-bit
** compilers.
*/
#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
#define LARGEST_UINT64 (0xffffffff|(((u64)0xffffffff)<<32))
#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)

/*
** Macro SMXV(n) return the maximum value that can be held in variable n,
** assuming n is a signed integer type.  UMXV(n) is similar for unsigned
** integer types.
*/
#define SMXV(n) ((((i64)1)<<(sizeof(n)-1))-1)
#define UMXV(n) ((((i64)1)<<(sizeof(n)))-1)

/*
** Round up a number to the next larger multiple of 8.  This is used
** to force 8-byte alignment on 64-bit architectures.
**
** ROUND8() always does the rounding, for any argument.
**
** ROUND8P() assumes that the argument is already an integer number of

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

      int nArg;            /* Number of arguments to the module */
      char **azArg;        /* 0: module 1: schema 2: vtab name 3...: args */
      VTable *p;           /* List of VTable objects. */
    } vtab;
  } u;
  Trigger *pTrigger;   /* List of triggers on this object */
  Schema *pSchema;     /* Schema that contains this table */
  u8 aHx[16];          /* Column aHt[K%sizeof(aHt)] might have hash K */
};

/*
** Allowed values for Table.tabFlags.
**
** TF_OOOHidden applies to tables or view that have hidden columns that are
** followed by non-hidden columns.  Example:  "CREATE VIRTUAL TABLE x USING

  /* 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 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 */

** list.
*/
struct Parse {
  sqlite3 *db;         /* The main database structure */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  int rc;              /* Return code from execution */
  LogEst nQueryLoop;   /* Est number of iterations of a query (10*log2(N)) */

  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */

  u8 disableLookaside; /* Number of times lookaside has been disabled */
  u8 prepFlags;        /* SQLITE_PREPARE_* flags */
  u8 withinRJSubrtn;   /* Nesting level for RIGHT JOIN body subroutines */

  u8 mSubrtnSig;       /* mini Bloom filter on available SubrtnSig.selId */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 bReturning;       /* Coding a RETURNING trigger */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */
#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
  u8 earlyCleanup;     /* OOM inside sqlite3ParserAddCleanup() */
#endif
#ifdef SQLITE_DEBUG
  u8 ifNotExists;      /* Might be true if IF NOT EXISTS.  Assert()s only */
  u8 isCreate;         /* CREATE TABLE, INDEX, or VIEW (but not TRIGGER)
                       ** and ALTER TABLE ADD COLUMN. */
#endif
  bft colNamesSet :1;   /* TRUE after OP_ColumnName has been issued to pVdbe */
  bft bHasWith :1;      /* True if statement contains WITH */
  bft okConstFactor :1; /* OK to factor out constants */
  bft checkSchema :1;   /* Causes schema cookie check after an error */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
  int iSelfTab;        /* Table associated with an index on expr, or negative
                       ** of the base register during check-constraint eval */
  int nLabel;          /* The *negative* of the number of labels used */
  int nLabelAlloc;     /* Number of slots in aLabel */
  int *aLabel;         /* Space to hold the labels */
  ExprList *pConstExpr;/* Constant expressions */
  IndexedExpr *pIdxEpr;/* List of expressions used by active indexes */
  IndexedExpr *pIdxPartExpr; /* Exprs constrained by index WHERE clauses */

  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */


  int nMaxArg;         /* Max args to xUpdate and xFilter vtab methods */
  int nSelect;         /* Number of SELECT stmts. Counter for Select.selId */
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  u32 nProgressSteps;  /* xProgress steps taken during sqlite3_prepare() */
#endif
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */












  /**************************************************************************
  ** Fields above must be initialized to zero.  The fields that follow,
  ** down to the beginning of the recursive section, do not need to be
  ** initialized as they will be set before being used.  The boundary is
  ** determined by offsetof(Parse,aTempReg).
  **************************************************************************/

  int aTempReg[8];        /* Holding area for temporary registers */
  Parse *pOuterParse;     /* Outer Parse object when nested */
  Token sNameToken;       /* Token with unqualified schema object name */
  u32 oldmask;            /* Mask of old.* columns referenced */
  u32 newmask;            /* Mask of new.* columns referenced */
  union {
    struct {  /* These fields available when isCreate is true */
      int addrCrTab;        /* Address of OP_CreateBtree on CREATE TABLE */
      int regRowid;         /* Register holding rowid of CREATE TABLE entry */
      int regRoot;          /* Register holding root page for new objects */
      Token constraintName; /* Name of the constraint currently being parsed */
    } cr;
    struct {  /* These fields available to all other statements */
      Returning *pReturning; /* The RETURNING clause */
    } d;
  } u1;

  /************************************************************************
  ** Above is constant between recursions.  Below is reset before and after
  ** each recursion.  The boundary between these two regions is determined
  ** using offsetof(Parse,sLastToken) so the sLastToken field must be the
  ** first field in the recursive region.
  ************************************************************************/

  Token sLastToken;       /* The last token parsed */
  ynVar nVar;               /* Number of '?' variables seen in the SQL so far */
  u8 iPkSortOrder;          /* ASC or DESC for INTEGER PRIMARY KEY */
  u8 explain;               /* True if the EXPLAIN flag is found on the query */
  u8 eParseMode;            /* PARSE_MODE_XXX constant */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int nVtabLock;            /* Number of virtual tables to lock */
#endif
  int nHeight;              /* Expression tree height of current sub-select */

  int addrExplain;          /* Address of current OP_Explain opcode */

  VList *pVList;            /* Mapping between variable names and numbers */
  Vdbe *pReprepare;         /* VM being reprepared (sqlite3Reprepare()) */
  const char *zTail;        /* All SQL text past the last semicolon parsed */
  Table *pNewTable;         /* A table being constructed by CREATE TABLE */
  Index *pNewIndex;         /* An index being constructed by CREATE INDEX.
                            ** Also used to hold redundant UNIQUE constraints
                            ** during a RENAME COLUMN */

** 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

  "ATOMIC_INTRINSICS=" CTIMEOPT_VAL(SQLITE_ATOMIC_INTRINSICS),
#endif
#ifdef SQLITE_BITMASK_TYPE
  "BITMASK_TYPE=" CTIMEOPT_VAL(SQLITE_BITMASK_TYPE),
#endif
#ifdef SQLITE_BUG_COMPATIBLE_20160819
  "BUG_COMPATIBLE_20160819",
#endif
#ifdef SQLITE_BUG_COMPATIBLE_20250510
  "BUG_COMPATIBLE_20250510",
#endif
#ifdef SQLITE_CASE_SENSITIVE_LIKE
  "CASE_SENSITIVE_LIKE",
#endif
#ifdef SQLITE_CHECK_PAGES
  "CHECK_PAGES",
#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

  i64 nChange;            /* Number of db changes made since last reset */
  int iStatement;         /* Statement number (or 0 if has no opened stmt) */
  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
  Mem *aMem;              /* The memory locations */
  Mem **apArg;            /* Arguments xUpdate and xFilter vtab methods */
  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
  Mem *aVar;              /* Values for the OP_Variable opcode. */

  /* When allocating a new Vdbe object, all of the fields below should be
  ** initialized to zero or NULL */

  Op *aOp;                /* Space to hold the virtual machine's program */
  int nOp;                /* Number of instructions in the program */
  int nOpAlloc;           /* Slots allocated for aOp[] */
  Mem *aColName;          /* Column names to return */
  Mem *pResultRow;        /* Current output row */
  char *zErrMsg;          /* Error message written here */
  VList *pVList;          /* Name of variables */
#ifndef SQLITE_OMIT_TRACE
  i64 startTime;          /* Time when query started - used for profiling */
#endif
#ifdef SQLITE_DEBUG
  int rcApp;              /* errcode set by sqlite3_result_error_code() */
  u32 nWrite;             /* Number of write operations that have occurred */
  int napArg;             /* Size of the apArg[] array */
#endif
  u16 nResColumn;         /* Number of columns in one row of the result set */
  u16 nResAlloc;          /* Column slots allocated to aColName[] */
  u8 errorAction;         /* Recovery action to do in case of an error */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 prepFlags;           /* SQLITE_PREPARE_* flags */
  u8 eVdbeState;          /* On of the VDBE_*_STATE values */

** 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 ){

** Finish off a string by making sure it is zero-terminated.
** Return a pointer to the resulting string.  Return a NULL
** pointer if any kind of error was encountered.
*/
static SQLITE_NOINLINE char *strAccumFinishRealloc(StrAccum *p){
  char *zText;
  assert( p->mxAlloc>0 && !isMalloced(p) );
  zText = sqlite3DbMallocRaw(p->db, 1+(u64)p->nChar );
  if( zText ){
    memcpy(zText, p->zText, p->nChar+1);
    p->printfFlags |= SQLITE_PRINTF_MALLOCED;
  }else{
    sqlite3StrAccumSetError(p, SQLITE_NOMEM);
  }
  p->zText = zText;

  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 four 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);

          j--;
        }
      }
    }
  }
  p->z = &p->zBuf[i+1];
  assert( i+p->n < sizeof(p->zBuf) );
  assert( p->n>0 );
  while( p->z[p->n-1]=='0' ){
    p->n--;
    assert( p->n>0 );
  }
}

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

  }
  *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;
}

}

/*
** The hashing function.
*/
static unsigned int strHash(const char *z){
  unsigned int h = 0;

  while( z[0] ){     /*OPTIMIZATION-IF-TRUE*/
    /* Knuth multiplicative hashing.  (Sorting & Searching, p. 510).
    ** 0x9e3779b1 is 2654435761 which is the closest prime number to
    ** (2**32)*golden_ratio, where golden_ratio = (sqrt(5) - 1)/2.
    **
    ** Only bits 0xdf for ASCII and bits 0xbf for EBCDIC each octet are
    ** hashed since the omitted bits determine the upper/lower case difference.
    */
#ifdef SQLITE_EBCDIC
    h += 0xbf & (unsigned char)*(z++);
#else
    h += 0xdf & (unsigned char)*(z++);
#endif
    h *= 0x9e3779b1;
  }
  return h;
}


/* Link pNew element into the hash table pH.  If pEntry!=0 then also

  if( new_ht==0 ) return 0;
  sqlite3_free(pH->ht);
  pH->ht = new_ht;
  pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
  memset(new_ht, 0, new_size*sizeof(struct _ht));
  for(elem=pH->first, pH->first=0; elem; elem = next_elem){

    next_elem = elem->next;
    insertElement(pH, &new_ht[elem->h % new_size], elem);
  }
  return 1;
}

/* This function (for internal use only) locates an element in an
** hash table that matches the given key.  If no element is found,
** a pointer to a static null element with HashElem.data==0 is returned.
** If pH is not NULL, then the hash for this key is written to *pH.
*/
static HashElem *findElementWithHash(
  const Hash *pH,     /* The pH to be searched */
  const char *pKey,   /* The key we are searching for */
  unsigned int *pHash /* Write the hash value here */
){
  HashElem *elem;                /* Used to loop thru the element list */
  unsigned int count;            /* Number of elements left to test */
  unsigned int h;                /* The computed hash */
  static HashElem nullElement = { 0, 0, 0, 0, 0 };

  h = strHash(pKey);
  if( pH->ht ){   /*OPTIMIZATION-IF-TRUE*/
    struct _ht *pEntry;

    pEntry = &pH->ht[h % pH->htsize];
    elem = pEntry->chain;
    count = pEntry->count;
  }else{

    elem = pH->first;
    count = pH->count;
  }
  if( pHash ) *pHash = h;
  while( count ){
    assert( elem!=0 );
    if( h==elem->h && sqlite3StrICmp(elem->pKey,pKey)==0 ){
      return elem;
    }
    elem = elem->next;
    count--;
  }
  return &nullElement;
}

/* Remove a single entry from the hash table given a pointer to that
** element and a hash on the element's key.
*/
static void removeElement(
  Hash *pH,         /* The pH containing "elem" */
  HashElem *elem    /* The element to be removed from the pH */

){
  struct _ht *pEntry;
  if( elem->prev ){
    elem->prev->next = elem->next;
  }else{
    pH->first = elem->next;
  }
  if( elem->next ){
    elem->next->prev = elem->prev;
  }
  if( pH->ht ){
    pEntry = &pH->ht[elem->h % pH->htsize];
    if( pEntry->chain==elem ){
      pEntry->chain = elem->next;
    }
    assert( pEntry->count>0 );
    pEntry->count--;
  }
  sqlite3_free( elem );

  assert( pH!=0 );
  assert( pKey!=0 );
  elem = findElementWithHash(pH,pKey,&h);
  if( elem->data ){
    void *old_data = elem->data;
    if( data==0 ){
      removeElement(pH,elem);
    }else{
      elem->data = data;
      elem->pKey = pKey;
    }
    return old_data;
  }
  if( data==0 ) return 0;
  new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
  if( new_elem==0 ) return data;
  new_elem->pKey = pKey;
  new_elem->h = h;
  new_elem->data = data;
  pH->count++;
  if( pH->count>=5 && pH->count > 2*pH->htsize ){
    rehash(pH, pH->count*3);


  }

  insertElement(pH, pH->ht ? &pH->ht[new_elem->h % pH->htsize] : 0, new_elem);
  return 0;
}

/************** End of hash.c ************************************************/
/************** Begin file opcodes.c *****************************************/
/* Automatically generated.  Do not edit */
/* See the tool/mkopcodec.tcl script for details. */

  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])) ){
      i64 nByte;
      int convertflag = CCP_POSIX_TO_WIN_W;
      if( !strchr(zFilename, '/') ) convertflag |= CCP_RELATIVE;
      nByte = (i64)osCygwin_conv_path(convertflag,
          zFilename, 0, 0);
      if( nByte>0 ){
        zConverted = sqlite3MallocZero(12+(u64)nByte);
        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.
*/










































/*
** 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;
  char *zBuf;

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

  /* Allocate a temporary buffer to store the fully qualified file
  ** name for the temporary file.  If this fails, we cannot continue.
  */
  nMax = pVfs->mxPathname;
  nBuf = 2 + (i64)nMax;
  zBuf = sqlite3MallocZero( nBuf );
  if( !zBuf ){
    OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
    return SQLITE_IOERR_NOMEM_BKPT;
  }

  /* Figure out the effective temporary directory.  First, check if one

      }
      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);






      }








    }











  }



#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 (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);

    char *zTemp;
    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0);
    if( nByte==0 ){
      sqlite3_free(zConverted);
      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
                         "winFullPathname3", zRelative);
    }

    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) + 3*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM_BKPT;
    }
    nByte = osGetFullPathNameA((char*)zConverted, nByte+3, zTemp, 0);
    if( nByte==0 ){
      sqlite3_free(zConverted);
      sqlite3_free(zTemp);
      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
                         "winFullPathname4", zRelative);
    }
    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;
















  void *zConverted = winConvertFromUtf8Filename(zFilename);
  UNUSED_PARAMETER(pVfs);

  if( zConverted==0 ){
    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
    return 0;
  }
  if( osIsNT() ){
#if SQLITE_OS_WINRT
    h = osLoadPackagedLibrary((LPCWSTR)zConverted, 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);

      if( strcmp(memdb_g.apMemStore[i]->zFName,zName)==0 ){
        p = memdb_g.apMemStore[i];
        break;
      }
    }
    if( p==0 ){
      MemStore **apNew;
      p = sqlite3Malloc( sizeof(*p) + (i64)szName + 3 );
      if( p==0 ){
        sqlite3_mutex_leave(pVfsMutex);
        return SQLITE_NOMEM;
      }
      apNew = sqlite3Realloc(memdb_g.apMemStore,
                             sizeof(apNew[0])*(1+(i64)memdb_g.nMemStore) );
      if( apNew==0 ){
        sqlite3_free(p);
        sqlite3_mutex_leave(pVfsMutex);
        return SQLITE_NOMEM;
      }
      apNew[memdb_g.nMemStore++] = p;
      memdb_g.apMemStore = apNew;

#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 rc = -1;
  int i, nx, pc, op;
  void *pTmpSpace;

  /* Allocate the Bitvec to be tested and a linear array of
  ** bits to act as the reference */
  pBitvec = sqlite3BitvecCreate( sz );
  pV = sqlite3MallocZero( (7+(i64)sz)/8 + 1 );
  pTmpSpace = sqlite3_malloc64(BITVEC_SZ);
  if( pBitvec==0 || pV==0 || pTmpSpace==0  ) goto bitvec_end;

  /* NULL pBitvec tests */
  sqlite3BitvecSet(0, 1);
  sqlite3BitvecClear(0, 1, pTmpSpace);

  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 ************************************/

/*
** This function is used to resize the hash table used by the cache passed
** as the first argument.
**
** The PCache mutex must be held when this function is called.
*/
static void pcache1ResizeHash(PCache1 *p){
  PgHdr1 **apNew;
  u64 nNew;
  u32 i;

  assert( sqlite3_mutex_held(p->pGroup->mutex) );

  nNew = 2*(u64)p->nHash;
  if( nNew<256 ){
    nNew = 256;
  }

  pcache1LeaveMutex(p->pGroup);
  if( p->nHash ){ sqlite3BeginBenignMalloc(); }
  apNew = (PgHdr1 **)sqlite3MallocZero(sizeof(PgHdr1 *)*nNew);

** Implementation of the sqlite3_pcache.xCreate method.
**
** Allocate a new cache.
*/
static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
  PCache1 *pCache;      /* The newly created page cache */
  PGroup *pGroup;       /* The group the new page cache will belong to */
  i64 sz;               /* Bytes of memory required to allocate the new cache */

  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
  assert( szExtra < 300 );

  sz = sizeof(PCache1) + sizeof(PGroup)*pcache1.separateCache;
  pCache = (PCache1 *)sqlite3MallocZero(sz);
  if( pCache ){

**
** If it is determined that no super-journal file name is present
** zSuper[0] is set to 0 and SQLITE_OK returned.
**
** If an error occurs while reading from the journal file, an SQLite
** error code is returned.
*/
static int readSuperJournal(sqlite3_file *pJrnl, char *zSuper, u64 nSuper){
  int rc;                    /* Return code */
  u32 len;                   /* Length in bytes of super-journal name */
  i64 szJ;                   /* Total size in bytes of journal file pJrnl */
  u32 cksum;                 /* MJ checksum value read from journal */
  u32 u;                     /* Unsigned loop counter */
  unsigned char aMagic[8];   /* A buffer to hold the magic header */
  zSuper[0] = '\0';

  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

  sqlite3_file *pSuper;     /* Malloc'd super-journal file descriptor */
  sqlite3_file *pJournal;   /* Malloc'd child-journal file descriptor */
  char *zSuperJournal = 0;  /* Contents of super-journal file */
  i64 nSuperJournal;        /* Size of super-journal file */
  char *zJournal;           /* Pointer to one journal within MJ file */
  char *zSuperPtr;          /* Space to hold super-journal filename */
  char *zFree = 0;          /* Free this buffer */
  i64 nSuperPtr;            /* Amount of space allocated to zSuperPtr[] */

  /* Allocate space for both the pJournal and pSuper file descriptors.
  ** If successful, open the super-journal file for reading.
  */
  pSuper = (sqlite3_file *)sqlite3MallocZero(2 * (i64)pVfs->szOsFile);
  if( !pSuper ){
    rc = SQLITE_NOMEM_BKPT;
    pJournal = 0;
  }else{
    const int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_SUPER_JOURNAL);
    rc = sqlite3OsOpen(pVfs, zSuper, pSuper, flags, 0);
    pJournal = (sqlite3_file *)(((u8 *)pSuper) + pVfs->szOsFile);
  }
  if( rc!=SQLITE_OK ) goto delsuper_out;

  /* Load the entire super-journal file into space obtained from
  ** sqlite3_malloc() and pointed to by zSuperJournal.   Also obtain
  ** sufficient space (in zSuperPtr) to hold the names of super-journal
  ** files extracted from regular rollback-journals.
  */
  rc = sqlite3OsFileSize(pSuper, &nSuperJournal);
  if( rc!=SQLITE_OK ) goto delsuper_out;
  nSuperPtr = 1 + (i64)pVfs->mxPathname;
  assert( nSuperJournal>=0 && nSuperPtr>0 );
  zFree = sqlite3Malloc(4 + nSuperJournal + nSuperPtr + 2);
  if( !zFree ){
    rc = SQLITE_NOMEM_BKPT;
    goto delsuper_out;
  }else{
    assert( nSuperJournal<=0x7fffffff );
  }
  zFree[0] = zFree[1] = zFree[2] = zFree[3] = 0;
  zSuperJournal = &zFree[4];
  zSuperPtr = &zSuperJournal[nSuperJournal+2];
  rc = sqlite3OsRead(pSuper, zSuperJournal, (int)nSuperJournal, 0);
  if( rc!=SQLITE_OK ) goto delsuper_out;
  zSuperJournal[nSuperJournal] = 0;

  ** TODO: Technically the following is an error because it assumes that
  ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
  ** (pPager->pageSize >= pPager->pVfs->mxPathname+1). Using os_unix.c,
  ** mxPathname is 512, which is the same as the minimum allowable value
  ** for pageSize.
  */
  zSuper = pPager->pTmpSpace;
  rc = readSuperJournal(pPager->jfd, zSuper, 1+(i64)pPager->pVfs->mxPathname);
  if( rc==SQLITE_OK && zSuper[0] ){
    rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
  }
  zSuper = 0;
  if( rc!=SQLITE_OK || !res ){
    goto end_playback;
  }

  if( rc==SQLITE_OK ){
    /* Leave 4 bytes of space before the super-journal filename in memory.
    ** This is because it may end up being passed to sqlite3OsOpen(), in
    ** which case it requires 4 0x00 bytes in memory immediately before
    ** the filename. */
    zSuper = &pPager->pTmpSpace[4];
    rc = readSuperJournal(pPager->jfd, zSuper, 1+(i64)pPager->pVfs->mxPathname);
    testcase( rc!=SQLITE_OK );
  }
  if( rc==SQLITE_OK
   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
  ){
    rc = sqlite3PagerSync(pPager, 0);
  }

  char *zPathname = 0;     /* Full path to database file */
  int nPathname = 0;       /* Number of bytes in zPathname */
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
  int pcacheSize = sqlite3PcacheSize();       /* Bytes to allocate for PCache */
  u32 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;  /* Default page size */
  const char *zUri = 0;    /* URI args to copy */
  int nUriByte = 1;        /* Number of bytes of URI args at *zUri */


  /* Figure out how much space is required for each journal file-handle
  ** (there are two of them, the main journal and the sub-journal).  */
  journalFileSize = ROUND8(sqlite3JournalSize(pVfs));

  /* Set the output variable to NULL in case an error occurs. */
  *ppPager = 0;

  /* Compute and store the full pathname in an allocated buffer pointed
  ** to by zPathname, length nPathname. Or, if this is a temporary file,
  ** leave both nPathname and zPathname set to 0.
  */
  if( zFilename && zFilename[0] ){
    const char *z;
    nPathname = pVfs->mxPathname + 1;
    zPathname = sqlite3DbMallocRaw(0, 2*(i64)nPathname);
    if( zPathname==0 ){
      return SQLITE_NOMEM_BKPT;
    }
    zPathname[0] = 0; /* Make sure initialized even if FullPathname() fails */
    rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_OK_SYMLINK ){

  ** changes here, be sure to change it there as well.
  */
  assert( SQLITE_PTRSIZE==sizeof(Pager*) );
  pPtr = (u8 *)sqlite3MallocZero(
    ROUND8(sizeof(*pPager)) +            /* Pager structure */
    ROUND8(pcacheSize) +                 /* PCache object */
    ROUND8(pVfs->szOsFile) +             /* The main db file */
    (u64)journalFileSize * 2 +           /* The two journal files */
    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
    4 +                                  /* Database prefix */
    (u64)nPathname + 1 +                 /* database filename */
    (u64)nUriByte +                      /* query parameters */
    (u64)nPathname + 8 + 1 +             /* Journal filename */
#ifndef SQLITE_OMIT_WAL
    (u64)nPathname + 4 + 1 +             /* WAL filename */
#endif
    3                                    /* Terminator */
  );
  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
  if( !pPtr ){
    sqlite3DbFree(0, zPathname);
    return SQLITE_NOMEM_BKPT;

#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

  int iPage,               /* The page we seek */
  volatile u32 **ppPage    /* Write the page pointer here */
){
  int rc = SQLITE_OK;

  /* Enlarge the pWal->apWiData[] array if required */
  if( pWal->nWiData<=iPage ){
    sqlite3_int64 nByte = sizeof(u32*)*(1+(i64)iPage);
    volatile u32 **apNew;
    apNew = (volatile u32 **)sqlite3Realloc((void *)pWal->apWiData, nByte);
    if( !apNew ){
      *ppPage = 0;
      return SQLITE_NOMEM_BKPT;
    }
    memset((void*)&apNew[pWal->nWiData], 0,

  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;

    ** that the current key is corrupt. In that case, it is possible that
    ** the sqlite3VdbeRecordUnpack() function may overread the buffer by
    ** up to the size of 1 varint plus 1 8-byte value when the cursor
    ** position is restored. Hence the 17 bytes of padding allocated
    ** below. */
    void *pKey;
    pCur->nKey = sqlite3BtreePayloadSize(pCur);
    pKey = sqlite3Malloc( ((i64)pCur->nKey) + 9 + 8 );
    if( pKey ){
      rc = sqlite3BtreePayload(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        memset(((u8*)pKey)+pCur->nKey, 0, 9+8);
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);

/*
** 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;
}

/*

        testcase( nCell==0 );  /* Invalid key size:  0x80 0x80 0x00 */
        testcase( nCell==1 );  /* Invalid key size:  0x80 0x80 0x01 */
        testcase( nCell==2 );  /* Minimum legal index key size */
        if( nCell<2 || nCell/pCur->pBt->usableSize>pCur->pBt->nPage ){
          rc = SQLITE_CORRUPT_PAGE(pPage);
          goto moveto_index_finish;
        }
        pCellKey = sqlite3Malloc( (u64)nCell+(u64)nOverrun );
        if( pCellKey==0 ){
          rc = SQLITE_NOMEM_BKPT;
          goto moveto_index_finish;
        }
        pCur->ix = (u16)idx;
        rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
        memset(((u8*)pCellKey)+nCell,0,nOverrun); /* Fix uninit warnings */

    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 ){

** Just before the shared-btree is closed, the function passed as the
** xFree argument when the memory allocation was made is invoked on the
** blob of allocated memory. The xFree function should not call sqlite3_free()
** on the memory, the btree layer does that.
*/
SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
  BtShared *pBt = p->pBt;
  assert( nBytes==0 || nBytes==sizeof(Schema) );
  sqlite3BtreeEnter(p);
  if( !pBt->pSchema && nBytes ){
    pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
    pBt->xFreeSchema = xFree;
  }
  sqlite3BtreeLeave(p);
  return pBt->pSchema;

**
** 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.
**

*/
SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
  if( (pMem->flags & (MEM_Str|MEM_Term|MEM_Ephem|MEM_Static))!=MEM_Str ){
    /* pMem must be a string, and it cannot be an ephemeral or static string */
    return;
  }
  if( pMem->enc!=SQLITE_UTF8 ) return;
  assert( pMem->z!=0 );
  if( pMem->flags & MEM_Dyn ){
    if( pMem->xDel==sqlite3_free
     && sqlite3_msize(pMem->z) >= (u64)(pMem->n+1)
    ){
      pMem->z[pMem->n] = 0;
      pMem->flags |= MEM_Term;
      return;

static sqlite3_value *valueNew(sqlite3 *db, struct ValueNewStat4Ctx *p){
#ifdef SQLITE_ENABLE_STAT4
  if( p ){
    UnpackedRecord *pRec = p->ppRec[0];

    if( pRec==0 ){
      Index *pIdx = p->pIdx;      /* Index being probed */
      i64 nByte;                  /* Bytes of space to allocate */
      int i;                      /* Counter variable */
      int nCol = pIdx->nColumn;   /* Number of index columns including rowid */

      nByte = sizeof(Mem) * nCol + ROUND8(sizeof(UnpackedRecord));
      pRec = (UnpackedRecord*)sqlite3DbMallocZero(db, nByte);
      if( pRec ){
        pRec->pKeyInfo = sqlite3KeyInfoOfIndex(p->pParse, pIdx);

  u8 enc,                         /* Encoding to use */
  u8 aff,                         /* Affinity to use */
  sqlite3_value **ppVal,          /* Write the new value here */
  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
){
  sqlite3_context ctx;            /* Context object for function invocation */
  sqlite3_value **apVal = 0;      /* Function arguments */
  int nVal = 0;                   /* Number of function arguments */
  FuncDef *pFunc = 0;             /* Function definition */
  sqlite3_value *pVal = 0;        /* New value */
  int rc = SQLITE_OK;             /* Return code */
  ExprList *pList = 0;            /* Function arguments */
  int i;                          /* Iterator variable */

  assert( pCtx!=0 );

  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;

    p->iAddr++;
    if( p->iAddr==nOp ){
      p->iSub++;
      p->iAddr = 0;
    }

    if( pRet->p4type==P4_SUBPROGRAM ){
      i64 nByte = (1+(u64)p->nSub)*sizeof(SubProgram*);
      int j;
      for(j=0; j<p->nSub; j++){
        if( p->apSub[j]==pRet->p4.pProgram ) break;
      }
      if( j==p->nSub ){
        p->apSub = sqlite3DbReallocOrFree(v->db, p->apSub, nByte);
        if( !p->apSub ){

/*
** This routine is called after all opcodes have been inserted.  It loops
** through all the opcodes and fixes up some details.
**
** (1) For each jump instruction with a negative P2 value (a label)
**     resolve the P2 value to an actual address.
**
** (2) Compute the maximum number of arguments used by the xUpdate/xFilter
**     methods of any virtual table and store that value in *pMaxVtabArgs.
**
** (3) Update the Vdbe.readOnly and Vdbe.bIsReader flags to accurately
**     indicate what the prepared statement actually does.
**
** (4) (discontinued)
**
** (5) Reclaim the memory allocated for storing labels.
**
** This routine will only function correctly if the mkopcodeh.tcl generator
** script numbers the opcodes correctly.  Changes to this routine must be
** coordinated with changes to mkopcodeh.tcl.
*/
static void resolveP2Values(Vdbe *p, int *pMaxVtabArgs){
  int nMaxVtabArgs = *pMaxVtabArgs;
  Op *pOp;
  Parse *pParse = p->pParse;
  int *aLabel = pParse->aLabel;

  assert( pParse->db->mallocFailed==0 ); /* tag-20230419-1 */
  p->readOnly = 1;
  p->bIsReader = 0;

        }
        case OP_Init: {
          assert( pOp->p2>=0 );
          goto resolve_p2_values_loop_exit;
        }
#ifndef SQLITE_OMIT_VIRTUALTABLE
        case OP_VUpdate: {
          if( pOp->p2>nMaxVtabArgs ) nMaxVtabArgs = pOp->p2;
          break;
        }
        case OP_VFilter: {
          int n;
          /* The instruction immediately prior to VFilter will be an
          ** OP_Integer that sets the "argc" value for the VFilter.  See
          ** the code where OP_VFilter is generated at tag-20250207a. */
          assert( (pOp - p->aOp) >= 3 );
          assert( pOp[-1].opcode==OP_Integer );
          assert( pOp[-1].p2==pOp->p3+1 );
          n = pOp[-1].p1;
          if( n>nMaxVtabArgs ) nMaxVtabArgs = n;
          /* Fall through into the default case */
          /* no break */ deliberate_fall_through
        }
#endif
        default: {
          if( pOp->p2<0 ){
            /* The mkopcodeh.tcl script has so arranged things that the only

  }
resolve_p2_values_loop_exit:
  if( aLabel ){
    sqlite3DbNNFreeNN(p->db, pParse->aLabel);
    pParse->aLabel = 0;
  }
  pParse->nLabel = 0;
  *pMaxVtabArgs = nMaxVtabArgs;
  assert( p->bIsReader!=0 || DbMaskAllZero(p->btreeMask) );
}

#ifdef SQLITE_DEBUG
/*
** Check to see if a subroutine contains a jump to a location outside of
** the subroutine.  If a jump outside the subroutine is detected, add code

  int addrExplain,                /* Address of OP_Explain (or 0) */
  int addrLoop,                   /* Address of loop counter */
  int addrVisit,                  /* Address of rows visited counter */
  LogEst nEst,                    /* Estimated number of output rows */
  const char *zName               /* Name of table or index being scanned */
){
  if( IS_STMT_SCANSTATUS(p->db) ){
    i64 nByte = (1+(i64)p->nScan) * sizeof(ScanStatus);
    ScanStatus *aNew;
    aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
    if( aNew ){
      ScanStatus *pNew = &aNew[p->nScan++];
      memset(pNew, 0, sizeof(ScanStatus));
      pNew->addrExplain = addrExplain;
      pNew->addrLoop = addrLoop;

/*
** 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

  Vdbe *p,                       /* The VDBE */
  Parse *pParse                  /* Parsing context */
){
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Max number args to xFilter or xUpdate */
  int n;                         /* Loop counter */
  struct ReusableSpace x;        /* Reusable bulk memory */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->eVdbeState==VDBE_INIT_STATE );

    if( !db->mallocFailed ){
      p->aMem = allocSpace(&x, p->aMem, nMem*sizeof(Mem));
      p->aVar = allocSpace(&x, p->aVar, nVar*sizeof(Mem));
      p->apArg = allocSpace(&x, p->apArg, nArg*sizeof(Mem*));
      p->apCsr = allocSpace(&x, p->apCsr, nCursor*sizeof(VdbeCursor*));
    }
  }
#ifdef SQLITE_DEBUG
  p->napArg = nArg;
#endif

  if( db->mallocFailed ){
    p->nVar = 0;
    p->nCursor = 0;
    p->nMem = 0;
  }else{
    p->nCursor = nCursor;

** If an OOM error occurs, NULL is returned.
*/
SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
  KeyInfo *pKeyInfo               /* Description of the record */
){
  UnpackedRecord *p;              /* Unpacked record to return */
  int nByte;                      /* Number of bytes required for *p */
  assert( sizeof(UnpackedRecord) + sizeof(Mem)*65536 < 0x7fffffff );
  nByte = ROUND8P(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nKeyField+1);
  p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
  if( !p ) return 0;
  p->aMem = (Mem*)&((char*)p)[ROUND8P(sizeof(UnpackedRecord))];
  assert( pKeyInfo->aSortFlags!=0 );
  p->pKeyInfo = pKeyInfo;
  p->nField = pKeyInfo->nKeyField + 1;

       || (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;
    }

    pMem = *ppValue = &p->pUnpacked->aMem[iStore];
    if( iStore>=p->pUnpacked->nField ){
      /* This occurs when the table has been extended using ALTER TABLE
      ** ADD COLUMN. The value to return is the default value of the column. */
      Column *pCol = &p->pTab->aCol[iIdx];
      if( pCol->iDflt>0 ){
        if( p->apDflt==0 ){
          int nByte;
          assert( sizeof(sqlite3_value*)*UMXV(p->pTab->nCol) < 0x7fffffff );
          nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
          p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
          if( p->apDflt==0 ) goto preupdate_old_out;
        }
        if( p->apDflt[iIdx]==0 ){
          sqlite3_value *pVal = 0;
          Expr *pDflt;
          assert( p->pTab!=0 && IsOrdinaryTable(p->pTab) );

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];
    if( iIdx==p->pTab->iPKey ){
      sqlite3VdbeMemSetInt64(pMem, p->iKey2);
    }else if( iStore>=pUnpack->nField ){
      pMem = (sqlite3_value *)columnNullValue();
    }
  }else{
    /* For an UPDATE, memory cell (p->iNewReg+1+iStore) contains the required
    ** value. Make a copy of the cell contents and return a pointer to it.
    ** It is not safe to return a pointer to the memory cell itself as the
    ** caller may modify the value text encoding.
    */
    assert( p->op==SQLITE_UPDATE );
    if( !p->aNew ){
      assert( sizeof(Mem)*UMXV(p->pCsr->nField) < 0x7fffffff );
      p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem)*p->pCsr->nField);
      if( !p->aNew ){
        rc = SQLITE_NOMEM;
        goto preupdate_new_out;
      }
    }
    assert( iStore>=0 && iStore<p->pCsr->nField );
    pMem = &p->aNew[iStore];

  **
  ** The memory cell for cursor 0 is aMem[0]. The rest are allocated from
  ** 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;
  }

      sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
    }
    pMem->z = pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, nByte);
    if( pMem->zMalloc==0 ){
      pMem->szMalloc = 0;
      return 0;
    }
    pMem->szMalloc = (int)nByte;
  }

  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) );

**
** P4 is a pointer to the VM containing the trigger program.
**
** If P5 is non-zero, then recursive program invocation is enabled.
*/
case OP_Program: {        /* jump0 */
  int nMem;               /* Number of memory registers for sub-program */
  i64 nByte;              /* Bytes of runtime space required for sub-program */
  Mem *pRt;               /* Register to allocate runtime space */
  Mem *pMem;              /* Used to iterate through memory cells */
  Mem *pEnd;              /* Last memory cell in new array */
  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
  SubProgram *pProgram;   /* Sub-program to execute */
  void *t;                /* Token identifying trigger */

    */
    nMem = pProgram->nMem + pProgram->nCsr;
    assert( nMem>0 );
    if( pProgram->nCsr==0 ) nMem++;
    nByte = ROUND8(sizeof(VdbeFrame))
              + nMem * sizeof(Mem)
              + pProgram->nCsr * sizeof(VdbeCursor*)
              + (7 + (i64)pProgram->nOp)/8;
    pFrame = sqlite3DbMallocZero(db, nByte);
    if( !pFrame ){
      goto no_mem;
    }
    sqlite3VdbeMemRelease(pRt);
    pRt->flags = MEM_Blob|MEM_Dyn;
    pRt->z = (char*)pFrame;
    pRt->n = (int)nByte;
    pRt->xDel = sqlite3VdbeFrameMemDel;

    pFrame->v = p;
    pFrame->nChildMem = nMem;
    pFrame->nChildCsr = pProgram->nCsr;
    pFrame->pc = (int)(pOp - aOp);
    pFrame->aMem = p->aMem;

**
** Increment a "constraint counter" by P2 (P2 may be negative or positive).
** If P1 is non-zero, the database constraint counter is incremented
** (deferred foreign key constraints). Otherwise, if P1 is zero, the
** statement counter is incremented (immediate foreign key constraints).
*/
case OP_FkCounter: {
  if( pOp->p1 ){
    db->nDeferredCons += pOp->p2;
  }else{
    if( db->flags & SQLITE_DeferFKs ){
      db->nDeferredImmCons += pOp->p2;


    }else{
      p->nFkConstraint += pOp->p2;
    }
  }
  break;
}

/* Opcode: FkIfZero P1 P2 * * *
** Synopsis: if fkctr[P1]==0 goto P2
**

  /* 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;

  /* Grab the index number and argc parameters */
  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
  nArg = (int)pArgc->u.i;
  iQuery = (int)pQuery->u.i;

  /* Invoke the xFilter method */
  apArg = p->apArg;
  assert( nArg<=p->napArg );
  for(i = 0; i<nArg; i++){
    apArg[i] = &pArgc[i+1];
  }
  rc = pModule->xFilter(pVCur, iQuery, pOp->p4.z, nArg, apArg);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( rc ) goto abort_due_to_error;
  res = pModule->xEof(pVCur);

  pModule = pVtab->pModule;
  nArg = pOp->p2;
  assert( pOp->p4type==P4_VTAB );
  if( ALWAYS(pModule->xUpdate) ){
    u8 vtabOnConflict = db->vtabOnConflict;
    apArg = p->apArg;
    pX = &aMem[pOp->p3];
    assert( nArg<=p->napArg );
    for(i=0; i<nArg; i++){
      assert( memIsValid(pX) );
      memAboutToChange(p, pX);
      apArg[i] = pX;
      pX++;
    }
    db->vtabOnConflict = pOp->p5;

#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;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

        /* 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.

  VdbeCursor *pCsr                /* Cursor that holds the new sorter */
){
  int pgsz;                       /* Page size of main database */
  int i;                          /* Used to iterate through aTask[] */
  VdbeSorter *pSorter;            /* The new sorter */
  KeyInfo *pKeyInfo;              /* Copy of pCsr->pKeyInfo with db==0 */
  int szKeyInfo;                  /* Size of pCsr->pKeyInfo in bytes */
  i64 sz;                         /* Size of pSorter in bytes */
  int rc = SQLITE_OK;
#if SQLITE_MAX_WORKER_THREADS==0
# define nWorker 0
#else
  int nWorker;
#endif

    nWorker = SORTER_MAX_MERGE_COUNT-1;
  }
#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;

** nReader PmaReader inputs.
**
** nReader is automatically rounded up to the next power of two.
** nReader may not exceed SORTER_MAX_MERGE_COUNT even after rounding up.
*/
static MergeEngine *vdbeMergeEngineNew(int nReader){
  int N = 2;                      /* Smallest power of two >= nReader */
  i64 nByte;                      /* Total bytes of space to allocate */
  MergeEngine *pNew;              /* Pointer to allocated object to return */

  assert( nReader<=SORTER_MAX_MERGE_COUNT );

  while( N<nReader ) N += N;
  nByte = sizeof(MergeEngine) + N * (sizeof(int) + sizeof(PmaReader));

    }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;

  sqlite3 *db = pParse->db;         /* The database connection */
  SrcItem *pItem;                   /* Use for looping over pSrcList items */
  SrcItem *pMatch = 0;              /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */
  Schema *pSchema = 0;              /* Schema of the expression */
  int eNewExprOp = TK_COLUMN;       /* New value for pExpr->op on success */
  Table *pTab = 0;                  /* Table holding the row */

  ExprList *pFJMatch = 0;           /* Matches for FULL JOIN .. USING */
  const char *zCol = pRight->u.zToken;

  assert( pNC );     /* the name context cannot be NULL. */
  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
  assert( zDb==0 || zTab!=0 );
  assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );

  assert( pNC && cnt==0 );
  do{
    ExprList *pEList;
    SrcList *pSrcList = pNC->pSrcList;

    if( pSrcList ){
      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){

        pTab = pItem->pSTab;
        assert( pTab!=0 && pTab->zName!=0 );
        assert( pTab->nCol>0 || pParse->nErr );
        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem));
        if( pItem->fg.isNestedFrom ){
          /* In this case, pItem is a subquery that has been formed from a
          ** parenthesized subset of the FROM clause terms.  Example: