sqllogictest

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.7.13.  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

/*
** Exactly one of the following macros must be defined in order to
** specify which memory allocation subsystem to use.
**
**     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
**     SQLITE_WIN32_MALLOC           // Use Win32 native heap API

**     SQLITE_MEMDEBUG               // Debugging version of system malloc()
**
** On Windows, if the SQLITE_WIN32_MALLOC_VALIDATE macro is defined and the
** assert() macro is enabled, each call into the Win32 native heap subsystem
** will cause HeapValidate to be called.  If heap validation should fail, an
** assertion will be triggered.
**
** (Historical note:  There used to be several other options, but we've
** pared it down to just these three.)
**
** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
** the default.
*/
#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_WIN32_MALLOC)+defined(SQLITE_MEMDEBUG)>1



# error "At most one of the following compile-time configuration options\

 is allows: SQLITE_SYSTEM_MALLOC, SQLITE_WIN32_MALLOC, SQLITE_MEMDEBUG"

#endif
#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_WIN32_MALLOC)+defined(SQLITE_MEMDEBUG)==0



# define SQLITE_SYSTEM_MALLOC 1
#endif

/*
** If SQLITE_MALLOC_SOFT_LIMIT is not zero, then try to keep the
** sizes of memory allocations below this value where possible.
*/

** string contains the date and time of the check-in (UTC) and an SHA1
** hash of the entire source tree.
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.13"
#define SQLITE_VERSION_NUMBER 3007013
#define SQLITE_SOURCE_ID      "2012-06-09 18:52:29 0ae0ce630a2e11f81dca50a9cfb04c4a41c03b2d"

/*
** 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

** CAPI3REF: Database Connection Handle
** KEYWORDS: {database connection} {database connections}
**
** Each open SQLite database is represented by a pointer to an instance of
** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]

** is its destructor.  There are many other interfaces (such as
** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
** [sqlite3_busy_timeout()] to name but three) that are methods on an
** sqlite3 object.
*/
typedef struct sqlite3 sqlite3;

/*

#ifdef SQLITE_OMIT_FLOATING_POINT
# define double sqlite3_int64
#endif

/*
** CAPI3REF: Closing A Database Connection
**

** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
** successfully destroyed and all associated resources are deallocated.

**











** Applications must [sqlite3_finalize | finalize] all [prepared statements]
** and [sqlite3_blob_close | close] all [BLOB handles] associated with

** the [sqlite3] object prior to attempting to close the object.  ^If
** sqlite3_close() is called on a [database connection] that still has
** outstanding [prepared statements] or [BLOB handles], then it returns
** SQLITE_BUSY.


**
** ^If [sqlite3_close()] is invoked while a transaction is open,
** the transaction is automatically rolled back.
**
** The C parameter to [sqlite3_close(C)] must be either a NULL

** pointer or an [sqlite3] object pointer obtained
** from [sqlite3_open()], [sqlite3_open16()], or
** [sqlite3_open_v2()], and not previously closed.
** ^Calling sqlite3_close() with a NULL pointer argument is a 
** harmless no-op.
*/
SQLITE_API int sqlite3_close(sqlite3 *);


/*
** The type for a callback function.
** This is legacy and deprecated.  It is included for historical
** compatibility and is not documented.
*/
typedef int (*sqlite3_callback)(void*,int,char**, char**);

/* Reserved:                         0x00F00000 */

/*
** CAPI3REF: Device Characteristics
**
** The xDeviceCharacteristics method of the [sqlite3_io_methods]
** object returns an integer which is a vector of the these
** bit values expressing I/O characteristics of the mass storage
** device that holds the file that the [sqlite3_io_methods]
** refers to.
**
** The SQLITE_IOCAP_ATOMIC property means that all writes of
** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
** mean that writes of blocks that are nnn bytes in size and

** the results are undefined.
**
** <b>Note to Windows users:</b>  The encoding used for the filename argument
** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
** codepage is currently defined.  Filenames containing international
** characters must be converted to UTF-8 prior to passing them into
** sqlite3_open() or sqlite3_open_v2().






*/
SQLITE_API int sqlite3_open(
  const char *filename,   /* Database filename (UTF-8) */
  sqlite3 **ppDb          /* OUT: SQLite db handle */
);
SQLITE_API int sqlite3_open16(
  const void *filename,   /* Database filename (UTF-16) */

** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
**
** ^The third argument is the value to bind to the parameter.
**
** ^(In those routines that have a fourth argument, its value is the
** number of bytes in the parameter.  To be clear: the value is the
** number of <u>bytes</u> in the value, not the number of characters.)^
** ^If the fourth parameter is negative, the length of the string is

** the number of bytes up to the first zero terminator.


** If a non-negative fourth parameter is provided to sqlite3_bind_text()
** or sqlite3_bind_text16() then that parameter must be the byte offset
** where the NUL terminator would occur assuming the string were NUL
** terminated.  If any NUL characters occur at byte offsets less than 
** the value of the fourth parameter then the resulting string value will
** contain embedded NULs.  The result of expressions involving strings
** with embedded NULs is undefined.

** they return.  Hence, the calling function can deallocate or
** modify the text after they return without harm.
** ^The sqlite3_result_error_code() function changes the error code
** returned by SQLite as a result of an error in a function.  ^By default,
** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
**
** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
** indicating that a string or BLOB is too long to represent.
**
** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
** indicating that a memory allocation failed.
**
** ^The sqlite3_result_int() interface sets the return value
** of the application-defined function to be the 32-bit signed integer
** value given in the 2nd argument.
** ^The sqlite3_result_int64() interface sets the return value
** of the application-defined function to be the 64-bit signed integer
** value given in the 2nd argument.

** the [temp_store_directory pragma] always assumes that any string
** that this variable points to is held in memory obtained from 
** [sqlite3_malloc] and the pragma may attempt to free that memory
** using [sqlite3_free].
** Hence, if this variable is modified directly, either it should be
** made NULL or made to point to memory obtained from [sqlite3_malloc]
** or else the use of the [temp_store_directory pragma] should be avoided.















*/
SQLITE_API char *sqlite3_temp_directory;

/*
** CAPI3REF: Name Of The Folder Holding Database Files
**
** ^(If this global variable is made to point to a string which is

**
** The SQLite source code contains multiple implementations
** of these mutex routines.  An appropriate implementation
** is selected automatically at compile-time.  ^(The following
** implementations are available in the SQLite core:
**
** <ul>
** <li>   SQLITE_MUTEX_OS2
** <li>   SQLITE_MUTEX_PTHREADS
** <li>   SQLITE_MUTEX_W32
** <li>   SQLITE_MUTEX_NOOP
** </ul>)^
**
** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
** that does no real locking and is appropriate for use in
** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations
** are appropriate for use on OS/2, Unix, and Windows.
**
** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
** implementation is included with the library. In this case the
** application must supply a custom mutex implementation using the
** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
** before calling sqlite3_initialize() or any other public sqlite3_

#define BTREE_FILE_FORMAT         2
#define BTREE_DEFAULT_CACHE_SIZE  3
#define BTREE_LARGEST_ROOT_PAGE   4
#define BTREE_TEXT_ENCODING       5
#define BTREE_USER_VERSION        6
#define BTREE_INCR_VACUUM         7







SQLITE_PRIVATE int sqlite3BtreeCursor(
  Btree*,                              /* BTree containing table to open */
  int iTable,                          /* Index of root page */
  int wrFlag,                          /* 1 for writing.  0 for read-only */
  struct KeyInfo*,                     /* First argument to compare function */
  BtCursor *pCursor                    /* Space to write cursor structure */
);

SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*);
SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);

SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *);
SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *);

SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);


#ifndef NDEBUG
SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor*);
#endif

#ifndef SQLITE_OMIT_BTREECOUNT
SQLITE_PRIVATE int sqlite3BtreeCount(BtCursor *, i64 *);

*/
#ifndef _SQLITE_OS_H_
#define _SQLITE_OS_H_

/*
** Figure out if we are dealing with Unix, Windows, or some other
** operating system.  After the following block of preprocess macros,
** all of SQLITE_OS_UNIX, SQLITE_OS_WIN, SQLITE_OS_OS2, and SQLITE_OS_OTHER 
** will defined to either 1 or 0.  One of the four will be 1.  The other 
** three will be 0.
*/
#if defined(SQLITE_OS_OTHER)
# if SQLITE_OS_OTHER==1
#   undef SQLITE_OS_UNIX
#   define SQLITE_OS_UNIX 0
#   undef SQLITE_OS_WIN
#   define SQLITE_OS_WIN 0
#   undef SQLITE_OS_OS2
#   define SQLITE_OS_OS2 0
# else
#   undef SQLITE_OS_OTHER
# endif
#endif
#if !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_OTHER)
# define SQLITE_OS_OTHER 0
# ifndef SQLITE_OS_WIN
#   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
#     define SQLITE_OS_WIN 1
#     define SQLITE_OS_UNIX 0
#     define SQLITE_OS_OS2 0
#   elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__)
#     define SQLITE_OS_WIN 0
#     define SQLITE_OS_UNIX 0
#     define SQLITE_OS_OS2 1
#   else
#     define SQLITE_OS_WIN 0
#     define SQLITE_OS_UNIX 1
#     define SQLITE_OS_OS2 0
#  endif
# else
#  define SQLITE_OS_UNIX 0
#  define SQLITE_OS_OS2 0
# endif
#else
# ifndef SQLITE_OS_WIN
#  define SQLITE_OS_WIN 0
# endif
#endif

#if SQLITE_OS_WIN
# include <windows.h>
#endif

#if SQLITE_OS_OS2
# if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_MEMORY)
#  include <os2safe.h> /* has to be included before os2.h for linking to work */
# endif
# define INCL_DOSDATETIME
# define INCL_DOSFILEMGR
# define INCL_DOSERRORS
# define INCL_DOSMISC
# define INCL_DOSPROCESS
# define INCL_DOSMODULEMGR
# define INCL_DOSSEMAPHORES
# include <os2.h>
# include <uconv.h>
#endif

/*
** Determine if we are dealing with Windows NT.
**
** We ought to be able to determine if we are compiling for win98 or winNT
** using the _WIN32_WINNT macro as follows:
**
** #if defined(_WIN32_WINNT)

#if defined(_WIN32_WCE)
# define SQLITE_OS_WINCE 1
#else
# define SQLITE_OS_WINCE 0
#endif

/*
** Determine if we are dealing with WindowsRT (Metro) as this has a different and
** incompatible API from win32.
*/
#if !defined(SQLITE_OS_WINRT)
# define SQLITE_OS_WINRT 0
#endif

/*
** When compiled for WinCE or WinRT, there is no concept of the current

**                             mutual exclusion is provided.  But this
**                             implementation can be overridden at
**                             start-time.
**
**   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
**
**   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
**
**   SQLITE_MUTEX_OS2          For multi-threaded applications on OS/2.
*/
#if !SQLITE_THREADSAFE
# define SQLITE_MUTEX_OMIT
#endif
#if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)
#  if SQLITE_OS_UNIX
#    define SQLITE_MUTEX_PTHREADS
#  elif SQLITE_OS_WIN
#    define SQLITE_MUTEX_W32
#  elif SQLITE_OS_OS2
#    define SQLITE_MUTEX_OS2
#  else
#    define SQLITE_MUTEX_NOOP
#  endif
#endif

#ifdef SQLITE_MUTEX_OMIT
/*

** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
#define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
#define SQLITE_MAGIC_SICK     0x4b771290  /* Error and awaiting close */
#define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
#define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */


/*
** Each SQL function is defined by an instance of the following
** structure.  A pointer to this structure is stored in the sqlite.aFunc
** hash table.  When multiple functions have the same name, the hash table
** points to a linked list of these structures.
*/

                         ** TK_REGISTER: register number
                         ** TK_TRIGGER: 1 -> new, 0 -> old */
  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
                         ** TK_VARIABLE: variable number (always >= 1). */
  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  i16 iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  u8 flags2;             /* Second set of flags.  EP2_... */
  u8 op2;                /* If a TK_REGISTER, the original value of Expr.op */
                         /* If TK_COLUMN, the value of p5 for OP_Column */

  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  Table *pTab;           /* Table for TK_COLUMN expressions. */
#if SQLITE_MAX_EXPR_DEPTH>0
  int nHeight;           /* Height of the tree headed by this node */
#endif
};

    sqlite3_index_info *pVtabIdx;  /* Virtual table index to use */
  } u;
};

/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
**
** The pIdxInfo field is used to help pick the best index on a
** virtual table.  The pIdxInfo pointer contains indexing
** information for the i-th table in the FROM clause before reordering.
** All the pIdxInfo pointers are freed by whereInfoFree() in where.c.
** All other information in the i-th WhereLevel object for the i-th table

    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
      } *aInLoop;           /* Information about each nested IN operator */
    } in;                 /* Used when plan.wsFlags&WHERE_IN_ABLE */

  } u;

  /* The following field is really not part of the current level.  But
  ** we need a place to cache virtual table index information for each
  ** virtual table in the FROM clause and the WhereLevel structure is
  ** a convenient place since there is one WhereLevel for each FROM clause
  ** element.

/*
** A structure used to customize the behavior of sqlite3Select(). See
** comments above sqlite3Select() for details.
*/
typedef struct SelectDest SelectDest;
struct SelectDest {
  u8 eDest;         /* How to dispose of the results */
  u8 affinity;      /* Affinity used when eDest==SRT_Set */
  int iParm;        /* A parameter used by the eDest disposal method */
  int iMem;         /* Base register where results are written */
  int nMem;         /* Number of registers allocated */
};

/*
** During code generation of statements that do inserts into AUTOINCREMENT 
** tables, the following information is attached to the Table.u.autoInc.p
** pointer of each autoincrement table to record some side information that
** the code generator needs.  We have to keep per-table autoincrement

#define OPFLAG_LASTROWID     0x02    /* Set to update db->lastRowid */
#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
#define OPFLAG_CLEARCACHE    0x20    /* Clear pseudo-table cache in OP_Column */
#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */



/*
 * Each trigger present in the database schema is stored as an instance of
 * struct Trigger. 
 *
 * Pointers to instances of struct Trigger are stored in two ways.
 * 1. In the "trigHash" hash table (part of the sqlite3* that represents the 

/*
** Context pointer passed down through the tree-walk.
*/
struct Walker {
  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
  int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
  Parse *pParse;                            /* Parser context.  */

  union {                                   /* Extra data for callback */
    NameContext *pNC;                          /* Naming context */
    int i;                                     /* Integer value */
    SrcList *pSrcList;                         /* FROM clause */

  } u;
};

/* Forward declarations */
SQLITE_PRIVATE int sqlite3WalkExpr(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3WalkExprList(Walker*, ExprList*);
SQLITE_PRIVATE int sqlite3WalkSelect(Walker*, Select*);

SQLITE_PRIVATE int sqlite3IsReadOnly(Parse*, Table*, int);
SQLITE_PRIVATE void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
SQLITE_PRIVATE Expr *sqlite3LimitWhere(Parse *, SrcList *, Expr *, ExprList *, Expr *, Expr *, char *);
#endif
SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**,ExprList*,u16);

SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse*, int, int, int);
SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse*, int, int, int);
SQLITE_PRIVATE void sqlite3ExprCacheStore(Parse*, int, int, int);
SQLITE_PRIVATE void sqlite3ExprCachePush(Parse*);

SQLITE_PRIVATE void sqlite3Vacuum(Parse*);
SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*);
SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, Token*);
SQLITE_PRIVATE int sqlite3ExprCompare(Expr*, Expr*);
SQLITE_PRIVATE int sqlite3ExprListCompare(ExprList*, ExprList*);
SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);

SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
SQLITE_PRIVATE void sqlite3PrngSaveState(void);
SQLITE_PRIVATE void sqlite3PrngRestoreState(void);
SQLITE_PRIVATE void sqlite3PrngResetState(void);
SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*,int);
SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse*, int);
SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
SQLITE_PRIVATE void sqlite3BeginTransaction(Parse*, int);
SQLITE_PRIVATE void sqlite3CommitTransaction(Parse*);
SQLITE_PRIVATE void sqlite3RollbackTransaction(Parse*);
SQLITE_PRIVATE void sqlite3Savepoint(Parse*, int, Token*);
SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *);

SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr*);
SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr*);
SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*);
SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr*, int*);
SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
SQLITE_PRIVATE void sqlite3ExprCodeIsNullJump(Vdbe*, const Expr*, int, int);
SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);

# define sqlite3VdbeSorterRowkey(Y,Z)    SQLITE_OK
# define sqlite3VdbeSorterRewind(X,Y,Z)  SQLITE_OK
# define sqlite3VdbeSorterNext(X,Y,Z)    SQLITE_OK
# define sqlite3VdbeSorterCompare(X,Y,Z) SQLITE_OK
#else
SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(VdbeCursor *, Mem *);
SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *, VdbeCursor *, int *);
SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *, VdbeCursor *, int *);
SQLITE_PRIVATE int sqlite3VdbeSorterWrite(sqlite3 *, VdbeCursor *, Mem *);
SQLITE_PRIVATE int sqlite3VdbeSorterCompare(VdbeCursor *, Mem *, int *);
#endif

#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
SQLITE_PRIVATE   void sqlite3VdbeEnter(Vdbe*);
SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
#else
# define sqlite3VdbeEnter(X)

  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
  if( cpuCount>1 ){
    /* defer MT decisions to system malloc */
    _sqliteZone_ = malloc_default_zone();
  }else{
    /* only 1 core, use our own zone to contention over global locks, 
    ** e.g. we have our own dedicated locks */
    bool success;		
    malloc_zone_t* newzone = malloc_create_zone(4096, 0);
    malloc_set_zone_name(newzone, "Sqlite_Heap");
    do{
      success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 
                                 (void * volatile *)&_sqliteZone_);
    }while(!_sqliteZone_);
    if( !success ){	
      /* somebody registered a zone first */
      malloc_destroy_zone(newzone);
    }
  }
#endif
  UNUSED_PARAMETER(NotUsed);
  return SQLITE_OK;

SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
  return sqlite3NoopMutex();
}
#endif /* defined(SQLITE_MUTEX_NOOP) */
#endif /* !defined(SQLITE_MUTEX_OMIT) */

/************** End of mutex_noop.c ******************************************/
/************** Begin file mutex_os2.c ***************************************/
/*
** 2007 August 28
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for OS/2
*/

/*
** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
** See the mutex.h file for details.
*/
#ifdef SQLITE_MUTEX_OS2

/********************** OS/2 Mutex Implementation **********************
**
** This implementation of mutexes is built using the OS/2 API.
*/

/*
** The mutex object
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  HMTX mutex;       /* Mutex controlling the lock */
  int  id;          /* Mutex type */
#ifdef SQLITE_DEBUG
 int   trace;       /* True to trace changes */
#endif
};

#ifdef SQLITE_DEBUG
#define SQLITE3_MUTEX_INITIALIZER { 0, 0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { 0, 0 }
#endif

/*
** Initialize and deinitialize the mutex subsystem.
*/
static int os2MutexInit(void){ return SQLITE_OK; }
static int os2MutexEnd(void){ return SQLITE_OK; }

/*
** The sqlite3_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
** SQLite will unwind its stack and return an error.  The argument
** to sqlite3_mutex_alloc() is one of these integer constants:
**
** <ul>
** <li>  SQLITE_MUTEX_FAST
** <li>  SQLITE_MUTEX_RECURSIVE
** <li>  SQLITE_MUTEX_STATIC_MASTER
** <li>  SQLITE_MUTEX_STATIC_MEM
** <li>  SQLITE_MUTEX_STATIC_MEM2
** <li>  SQLITE_MUTEX_STATIC_PRNG
** <li>  SQLITE_MUTEX_STATIC_LRU
** <li>  SQLITE_MUTEX_STATIC_LRU2
** </ul>
**
** The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
** The mutex implementation does not need to make a distinction
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
** not want to.  But SQLite will only request a recursive mutex in
** cases where it really needs one.  If a faster non-recursive mutex
** implementation is available on the host platform, the mutex subsystem
** might return such a mutex in response to SQLITE_MUTEX_FAST.
**
** The other allowed parameters to sqlite3_mutex_alloc() each return
** a pointer to a static preexisting mutex.  Six static mutexes are
** used by the current version of SQLite.  Future versions of SQLite
** may add additional static mutexes.  Static mutexes are for internal
** use by SQLite only.  Applications that use SQLite mutexes should
** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
** SQLITE_MUTEX_RECURSIVE.
**
** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
** returns a different mutex on every call.  But for the static
** mutex types, the same mutex is returned on every call that has
** the same type number.
*/
static sqlite3_mutex *os2MutexAlloc(int iType){
  sqlite3_mutex *p = NULL;
  switch( iType ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){
        p->id = iType;
        if( DosCreateMutexSem( 0, &p->mutex, 0, FALSE ) != NO_ERROR ){
          sqlite3_free( p );
          p = NULL;
        }
      }
      break;
    }
    default: {
      static volatile int isInit = 0;
      static sqlite3_mutex staticMutexes[6] = {
        SQLITE3_MUTEX_INITIALIZER,
        SQLITE3_MUTEX_INITIALIZER,
        SQLITE3_MUTEX_INITIALIZER,
        SQLITE3_MUTEX_INITIALIZER,
        SQLITE3_MUTEX_INITIALIZER,
        SQLITE3_MUTEX_INITIALIZER,
      };
      if ( !isInit ){
        APIRET rc;
        PTIB ptib;
        PPIB ppib;
        HMTX mutex;
        char name[32];
        DosGetInfoBlocks( &ptib, &ppib );
        sqlite3_snprintf( sizeof(name), name, "\\SEM32\\SQLITE%04x",
                          ppib->pib_ulpid );
        while( !isInit ){
          mutex = 0;
          rc = DosCreateMutexSem( name, &mutex, 0, FALSE);
          if( rc == NO_ERROR ){
            unsigned int i;
            if( !isInit ){
              for( i = 0; i < sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++ ){
                DosCreateMutexSem( 0, &staticMutexes[i].mutex, 0, FALSE );
              }
              isInit = 1;
            }
            DosCloseMutexSem( mutex );
          }else if( rc == ERROR_DUPLICATE_NAME ){
            DosSleep( 1 );
          }else{
            return p;
          }
        }
      }
      assert( iType-2 >= 0 );
      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
      p = &staticMutexes[iType-2];
      p->id = iType;
      break;
    }
  }
  return p;
}


/*
** This routine deallocates a previously allocated mutex.
** SQLite is careful to deallocate every mutex that it allocates.
*/
static void os2MutexFree(sqlite3_mutex *p){
#ifdef SQLITE_DEBUG
  TID tid;
  PID pid;
  ULONG ulCount;
  DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
  assert( ulCount==0 );
  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
#endif
  DosCloseMutexSem( p->mutex );
  sqlite3_free( p );
}

#ifdef SQLITE_DEBUG
/*
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
** intended for use inside assert() statements.
*/
static int os2MutexHeld(sqlite3_mutex *p){
  TID tid;
  PID pid;
  ULONG ulCount;
  PTIB ptib;
  DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
  if( ulCount==0 || ( ulCount>1 && p->id!=SQLITE_MUTEX_RECURSIVE ) )
    return 0;
  DosGetInfoBlocks(&ptib, NULL);
  return tid==ptib->tib_ptib2->tib2_ultid;
}
static int os2MutexNotheld(sqlite3_mutex *p){
  TID tid;
  PID pid;
  ULONG ulCount;
  PTIB ptib;
  DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
  if( ulCount==0 )
    return 1;
  DosGetInfoBlocks(&ptib, NULL);
  return tid!=ptib->tib_ptib2->tib2_ultid;
}
static void os2MutexTrace(sqlite3_mutex *p, char *pAction){
  TID   tid;
  PID   pid;
  ULONG ulCount;
  DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
  printf("%s mutex %p (%d) with nRef=%ld\n", pAction, (void*)p, p->trace, ulCount);
}
#endif

/*
** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
** to enter a mutex.  If another thread is already within the mutex,
** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
** be entered multiple times by the same thread.  In such cases the,
** mutex must be exited an equal number of times before another thread
** can enter.  If the same thread tries to enter any other kind of mutex
** more than once, the behavior is undefined.
*/
static void os2MutexEnter(sqlite3_mutex *p){
  assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) );
  DosRequestMutexSem(p->mutex, SEM_INDEFINITE_WAIT);
#ifdef SQLITE_DEBUG
  if( p->trace ) os2MutexTrace(p, "enter");
#endif
}
static int os2MutexTry(sqlite3_mutex *p){
  int rc = SQLITE_BUSY;
  assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) );
  if( DosRequestMutexSem(p->mutex, SEM_IMMEDIATE_RETURN) == NO_ERROR ) {
    rc = SQLITE_OK;
#ifdef SQLITE_DEBUG
    if( p->trace ) os2MutexTrace(p, "try");
#endif
  }
  return rc;
}

/*
** The sqlite3_mutex_leave() routine exits a mutex that was
** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void os2MutexLeave(sqlite3_mutex *p){
  assert( os2MutexHeld(p) );
  DosReleaseMutexSem(p->mutex);
#ifdef SQLITE_DEBUG
  if( p->trace ) os2MutexTrace(p, "leave");
#endif
}

SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
  static const sqlite3_mutex_methods sMutex = {
    os2MutexInit,
    os2MutexEnd,
    os2MutexAlloc,
    os2MutexFree,
    os2MutexEnter,
    os2MutexTry,
    os2MutexLeave,
#ifdef SQLITE_DEBUG
    os2MutexHeld,
    os2MutexNotheld
#else
    0,
    0
#endif
  };

  return &sMutex;
}
#endif /* SQLITE_MUTEX_OS2 */

/************** End of mutex_os2.c *******************************************/
/************** Begin file mutex_unix.c **************************************/
/*
** 2007 August 28
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**

/* As winMutexInit() and winMutexEnd() are called as part
** of the sqlite3_initialize and sqlite3_shutdown()
** processing, the "interlocked" magic is probably not
** strictly necessary.
*/
static long winMutex_lock = 0;

SQLITE_API extern void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */

static int winMutexInit(void){ 
  /* The first to increment to 1 does actual initialization */
  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){
    int i;
    for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
#if SQLITE_OS_WINRT

** The counter *cnt is incremented each time.  After counter exceeds
** 16 (the number of significant digits in a 64-bit float) '0' is
** always returned.
*/
static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
  int digit;
  LONGDOUBLE_TYPE d;
  if( (*cnt)++ >= 16 ) return '0';

  digit = (int)*val;
  d = digit;
  digit += '0';
  *val = (*val - d)*10.0;
  return (char)digit;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */

        exp = 0;
        if( sqlite3IsNaN((double)realvalue) ){
          bufpt = "NaN";
          length = 3;
          break;
        }
        if( realvalue>0.0 ){

          while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }

          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }

          while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
          while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
          if( exp>350 ){
            if( prefix=='-' ){
              bufpt = "-Inf";
            }else if( prefix=='+' ){
              bufpt = "+Inf";

          if( exp<-4 || exp>precision ){
            xtype = etEXP;
          }else{
            precision = precision - exp;
            xtype = etFLOAT;
          }
        }else{
          flag_rtz = 0;
        }
        if( xtype==etEXP ){
          e2 = 0;
        }else{
          e2 = exp;
        }
        if( e2+precision+width > etBUFSIZE - 15 ){
          bufpt = zExtra = sqlite3Malloc( e2+precision+width+15 );
          if( bufpt==0 ){
            pAccum->mallocFailed = 1;
            return;
          }
        }
        zOut = bufpt;
        nsd = 0;
        flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
        /* The sign in front of the number */
        if( prefix ){
          *(bufpt++) = prefix;
        }
        /* Digits prior to the decimal point */
        if( e2<0 ){

    /* adjust the sign of significand */
    s = sign<0 ? -s : s;

    /* if exponent, scale significand as appropriate
    ** and store in result. */
    if( e ){
      double scale = 1.0;
      /* attempt to handle extremely small/large numbers better */
      if( e>307 && e<342 ){
        while( e%308 ) { scale *= 1.0e+1; e -= 1; }
        if( esign<0 ){
          result = s / scale;
          result /= 1.0e+308;
        }else{

    new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
  }
  if( new_size==pH->htsize ) return 0;
#endif

  /* The inability to allocates space for a larger hash table is
  ** a performance hit but it is not a fatal error.  So mark the
  ** allocation as a benign.




  */
  sqlite3BeginBenignMalloc();
  new_ht = (struct _ht *)sqlite3Malloc( new_size*sizeof(struct _ht) );
  sqlite3EndBenignMalloc();

  if( new_ht==0 ) return 0;
  sqlite3_free(pH->ht);

     /* 150 */ "Explain",
  };
  return azName[i];
}
#endif

/************** End of opcodes.c *********************************************/
/************** Begin file os_os2.c ******************************************/
/*
** 2006 Feb 14
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to OS/2.
*/


#if SQLITE_OS_OS2

/*
** A Note About Memory Allocation:
**
** This driver uses malloc()/free() directly rather than going through
** the SQLite-wrappers sqlite3_malloc()/sqlite3_free().  Those wrappers
** are designed for use on embedded systems where memory is scarce and
** malloc failures happen frequently.  OS/2 does not typically run on
** embedded systems, and when it does the developers normally have bigger
** problems to worry about than running out of memory.  So there is not
** a compelling need to use the wrappers.
**
** But there is a good reason to not use the wrappers.  If we use the
** wrappers then we will get simulated malloc() failures within this
** driver.  And that causes all kinds of problems for our tests.  We
** could enhance SQLite to deal with simulated malloc failures within
** the OS driver, but the code to deal with those failure would not
** be exercised on Linux (which does not need to malloc() in the driver)
** and so we would have difficulty writing coverage tests for that
** code.  Better to leave the code out, we think.
**
** The point of this discussion is as follows:  When creating a new
** OS layer for an embedded system, if you use this file as an example,
** avoid the use of malloc()/free().  Those routines work ok on OS/2
** desktops but not so well in embedded systems.
*/

/*
** Macros used to determine whether or not to use threads.
*/
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE
# define SQLITE_OS2_THREADS 1
#endif

/*
** Include code that is common to all os_*.c files
*/
/************** Include os_common.h in the middle of os_os2.c ****************/
/************** Begin file os_common.h ***************************************/
/*
** 2004 May 22
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains macros and a little bit of code that is common to
** all of the platform-specific files (os_*.c) and is #included into those
** files.
**
** This file should be #included by the os_*.c files only.  It is not a
** general purpose header file.
*/
#ifndef _OS_COMMON_H_
#define _OS_COMMON_H_

/*
** At least two bugs have slipped in because we changed the MEMORY_DEBUG
** macro to SQLITE_DEBUG and some older makefiles have not yet made the
** switch.  The following code should catch this problem at compile-time.
*/
#ifdef MEMORY_DEBUG
# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
#endif

#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
# ifndef SQLITE_DEBUG_OS_TRACE
#   define SQLITE_DEBUG_OS_TRACE 0
# endif
  int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
# define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
#else
# define OSTRACE(X)
#endif

/*
** Macros for performance tracing.  Normally turned off.  Only works
** on i486 hardware.
*/
#ifdef SQLITE_PERFORMANCE_TRACE

/* 
** hwtime.h contains inline assembler code for implementing 
** high-performance timing routines.
*/
/************** Include hwtime.h in the middle of os_common.h ****************/
/************** Begin file hwtime.h ******************************************/
/*
** 2008 May 27
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains inline asm code for retrieving "high-performance"
** counters for x86 class CPUs.
*/
#ifndef _HWTIME_H_
#define _HWTIME_H_

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

  #if defined(__GNUC__)

  __inline__ sqlite_uint64 sqlite3Hwtime(void){
     unsigned int lo, hi;
     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
     return (sqlite_uint64)hi << 32 | lo;
  }

  #elif defined(_MSC_VER)

  __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){
     __asm {
        rdtsc
        ret       ; return value at EDX:EAX
     }
  }

  #endif

#elif (defined(__GNUC__) && defined(__x86_64__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){
      unsigned long val;
      __asm__ __volatile__ ("rdtsc" : "=A" (val));
      return val;
  }
 
#elif (defined(__GNUC__) && defined(__ppc__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){
      unsigned long long retval;
      unsigned long junk;
      __asm__ __volatile__ ("\n\
          1:      mftbu   %1\n\
                  mftb    %L0\n\
                  mftbu   %0\n\
                  cmpw    %0,%1\n\
                  bne     1b"
                  : "=r" (retval), "=r" (junk));
      return retval;
  }

#else

  #error Need implementation of sqlite3Hwtime() for your platform.

  /*
  ** To compile without implementing sqlite3Hwtime() for your platform,
  ** you can remove the above #error and use the following
  ** stub function.  You will lose timing support for many
  ** of the debugging and testing utilities, but it should at
  ** least compile and run.
  */
SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }

#endif

#endif /* !defined(_HWTIME_H_) */

/************** End of hwtime.h **********************************************/
/************** Continuing where we left off in os_common.h ******************/

static sqlite_uint64 g_start;
static sqlite_uint64 g_elapsed;
#define TIMER_START       g_start=sqlite3Hwtime()
#define TIMER_END         g_elapsed=sqlite3Hwtime()-g_start
#define TIMER_ELAPSED     g_elapsed
#else
#define TIMER_START
#define TIMER_END
#define TIMER_ELAPSED     ((sqlite_uint64)0)
#endif

/*
** If we compile with the SQLITE_TEST macro set, then the following block
** of code will give us the ability to simulate a disk I/O error.  This
** is used for testing the I/O recovery logic.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
SQLITE_API int sqlite3_diskfull_pending = 0;
SQLITE_API int sqlite3_diskfull = 0;
#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
#define SimulateIOError(CODE)  \
  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
       || sqlite3_io_error_pending-- == 1 )  \
              { local_ioerr(); CODE; }
static void local_ioerr(){
  IOTRACE(("IOERR\n"));
  sqlite3_io_error_hit++;
  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
}
#define SimulateDiskfullError(CODE) \
   if( sqlite3_diskfull_pending ){ \
     if( sqlite3_diskfull_pending == 1 ){ \
       local_ioerr(); \
       sqlite3_diskfull = 1; \
       sqlite3_io_error_hit = 1; \
       CODE; \
     }else{ \
       sqlite3_diskfull_pending--; \
     } \
   }
#else
#define SimulateIOErrorBenign(X)
#define SimulateIOError(A)
#define SimulateDiskfullError(A)
#endif

/*
** When testing, keep a count of the number of open files.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_open_file_count = 0;
#define OpenCounter(X)  sqlite3_open_file_count+=(X)
#else
#define OpenCounter(X)
#endif

#endif /* !defined(_OS_COMMON_H_) */

/************** End of os_common.h *******************************************/
/************** Continuing where we left off in os_os2.c *********************/

/* Forward references */
typedef struct os2File os2File;         /* The file structure */
typedef struct os2ShmNode os2ShmNode;   /* A shared descritive memory node */
typedef struct os2ShmLink os2ShmLink;   /* A connection to shared-memory */

/*
** The os2File structure is subclass of sqlite3_file specific for the OS/2
** protability layer.
*/
struct os2File {
  const sqlite3_io_methods *pMethod;  /* Always the first entry */
  HFILE h;                  /* Handle for accessing the file */
  int flags;                /* Flags provided to os2Open() */
  int locktype;             /* Type of lock currently held on this file */
  int szChunk;              /* Chunk size configured by FCNTL_CHUNK_SIZE */
  char *zFullPathCp;        /* Full path name of this file */
  os2ShmLink *pShmLink;     /* Instance of shared memory on this file */
};

#define LOCK_TIMEOUT 10L /* the default locking timeout */

/*
** Missing from some versions of the OS/2 toolkit -
** used to allocate from high memory if possible
*/
#ifndef OBJ_ANY
# define OBJ_ANY 0x00000400
#endif

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

/*
** Close a file.
*/
static int os2Close( sqlite3_file *id ){
  APIRET rc;
  os2File *pFile = (os2File*)id;

  assert( id!=0 );
  OSTRACE(( "CLOSE %d (%s)\n", pFile->h, pFile->zFullPathCp ));

  rc = DosClose( pFile->h );

  if( pFile->flags & SQLITE_OPEN_DELETEONCLOSE )
    DosForceDelete( (PSZ)pFile->zFullPathCp );

  free( pFile->zFullPathCp );
  pFile->zFullPathCp = NULL;
  pFile->locktype = NO_LOCK;
  pFile->h = (HFILE)-1;
  pFile->flags = 0;

  OpenCounter( -1 );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int os2Read(
  sqlite3_file *id,               /* File to read from */
  void *pBuf,                     /* Write content into this buffer */
  int amt,                        /* Number of bytes to read */
  sqlite3_int64 offset            /* Begin reading at this offset */
){
  ULONG fileLocation = 0L;
  ULONG got;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_READ );
  OSTRACE(( "READ %d lock=%d\n", pFile->h, pFile->locktype ));
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  if( DosRead( pFile->h, pBuf, amt, &got ) != NO_ERROR ){
    return SQLITE_IOERR_READ;
  }
  if( got == (ULONG)amt )
    return SQLITE_OK;
  else {
    /* Unread portions of the input buffer must be zero-filled */
    memset(&((char*)pBuf)[got], 0, amt-got);
    return SQLITE_IOERR_SHORT_READ;
  }
}

/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
static int os2Write(
  sqlite3_file *id,               /* File to write into */
  const void *pBuf,               /* The bytes to be written */
  int amt,                        /* Number of bytes to write */
  sqlite3_int64 offset            /* Offset into the file to begin writing at */
){
  ULONG fileLocation = 0L;
  APIRET rc = NO_ERROR;
  ULONG wrote;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_WRITE );
  SimulateDiskfullError( return SQLITE_FULL );
  OSTRACE(( "WRITE %d lock=%d\n", pFile->h, pFile->locktype ));
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  assert( amt>0 );
  while( amt > 0 &&
         ( rc = DosWrite( pFile->h, (PVOID)pBuf, amt, &wrote ) ) == NO_ERROR &&
         wrote > 0
  ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }

  return ( rc != NO_ERROR || amt > (int)wrote ) ? SQLITE_FULL : SQLITE_OK;
}

/*
** Truncate an open file to a specified size
*/
static int os2Truncate( sqlite3_file *id, i64 nByte ){
  APIRET rc;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  OSTRACE(( "TRUNCATE %d %lld\n", pFile->h, nByte ));
  SimulateIOError( return SQLITE_IOERR_TRUNCATE );

  /* If the user has configured a chunk-size for this file, truncate the
  ** file so that it consists of an integer number of chunks (i.e. the
  ** actual file size after the operation may be larger than the requested
  ** size).
  */
  if( pFile->szChunk ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }
  
  rc = DosSetFileSize( pFile->h, nByte );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_TRUNCATE;
}

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

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int os2Sync( sqlite3_file *id, int flags ){
  os2File *pFile = (os2File*)id;
  OSTRACE(( "SYNC %d lock=%d\n", pFile->h, pFile->locktype ));
#ifdef SQLITE_TEST
  if( flags & SQLITE_SYNC_FULL){
    sqlite3_fullsync_count++;
  }
  sqlite3_sync_count++;
#endif
  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
  ** no-op
  */
#ifdef SQLITE_NO_SYNC
  UNUSED_PARAMETER(pFile);
  return SQLITE_OK;
#else
  return DosResetBuffer( pFile->h ) == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
#endif
}

/*
** Determine the current size of a file in bytes
*/
static int os2FileSize( sqlite3_file *id, sqlite3_int64 *pSize ){
  APIRET rc = NO_ERROR;
  FILESTATUS3 fsts3FileInfo;
  memset(&fsts3FileInfo, 0, sizeof(fsts3FileInfo));
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_FSTAT );
  rc = DosQueryFileInfo( ((os2File*)id)->h, FIL_STANDARD, &fsts3FileInfo, sizeof(FILESTATUS3) );
  if( rc == NO_ERROR ){
    *pSize = fsts3FileInfo.cbFile;
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR_FSTAT;
  }
}

/*
** Acquire a reader lock.
*/
static int getReadLock( os2File *pFile ){
  FILELOCK  LockArea,
            UnlockArea;
  APIRET res;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = SHARED_FIRST;
  LockArea.lRange = SHARED_SIZE;
  UnlockArea.lOffset = 0L;
  UnlockArea.lRange = 0L;
  res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE(( "GETREADLOCK %d res=%d\n", pFile->h, res ));
  return res;
}

/*
** Undo a readlock
*/
static int unlockReadLock( os2File *id ){
  FILELOCK  LockArea,
            UnlockArea;
  APIRET res;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = 0L;
  LockArea.lRange = 0L;
  UnlockArea.lOffset = SHARED_FIRST;
  UnlockArea.lRange = SHARED_SIZE;
  res = DosSetFileLocks( id->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE(( "UNLOCK-READLOCK file handle=%d res=%d?\n", id->h, res ));
  return res;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
** Sometimes when requesting one lock state, additional lock states
** are inserted in between.  The locking might fail on one of the later
** transitions leaving the lock state different from what it started but
** still short of its goal.  The following chart shows the allowed
** transitions and the inserted intermediate states:
**
**    UNLOCKED -> SHARED
**    SHARED -> RESERVED
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  The os2Unlock() routine
** erases all locks at once and returns us immediately to locking level 0.
** It is not possible to lower the locking level one step at a time.  You
** must go straight to locking level 0.
*/
static int os2Lock( sqlite3_file *id, int locktype ){
  int rc = SQLITE_OK;       /* Return code from subroutines */
  APIRET res = NO_ERROR;    /* Result of an OS/2 lock call */
  int newLocktype;       /* Set pFile->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  FILELOCK  LockArea,
            UnlockArea;
  os2File *pFile = (os2File*)id;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  OSTRACE(( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype ));

  /* If there is already a lock of this type or more restrictive on the
  ** os2File, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3_mutex_enter() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE(( "LOCK %d %d ok (already held)\n", pFile->h, locktype ));
    return SQLITE_OK;
  }

  /* 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 a PENDING 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( pFile->locktype==NO_LOCK
      || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
  ){
    LockArea.lOffset = PENDING_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;

    /* wait longer than LOCK_TIMEOUT here not to have to try multiple times */
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 100L, 0L );
    if( res == NO_ERROR ){
      gotPendingLock = 1;
      OSTRACE(( "LOCK %d pending lock boolean set.  res=%d\n", pFile->h, res ));
    }
  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==NO_LOCK );
    res = getReadLock(pFile);
    if( res == NO_ERROR ){
      newLocktype = SHARED_LOCK;
    }
    OSTRACE(( "LOCK %d acquire shared lock. res=%d\n", pFile->h, res ));
  }

  /* Acquire a RESERVED lock
  */
  if( locktype==RESERVED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==SHARED_LOCK );
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = RESERVED_LOCK;
    }
    OSTRACE(( "LOCK %d acquire reserved lock. res=%d\n", pFile->h, res ));
  }

  /* Acquire a PENDING lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
    OSTRACE(( "LOCK %d acquire pending lock. pending lock boolean unset.\n",
               pFile->h ));
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE(( "unreadlock = %d\n", res ));
    LockArea.lOffset = SHARED_FIRST;
    LockArea.lRange = SHARED_SIZE;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      OSTRACE(( "OS/2 error-code = %d\n", res ));
      getReadLock(pFile);
    }
    OSTRACE(( "LOCK %d acquire exclusive lock.  res=%d\n", pFile->h, res ));
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    int r;
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    r = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "LOCK %d unlocking pending/is shared. r=%d\n", pFile->h, r ));
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res == NO_ERROR ){
    rc = SQLITE_OK;
  }else{
    OSTRACE(( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
              locktype, newLocktype ));
    rc = SQLITE_BUSY;
  }
  pFile->locktype = newLocktype;
  OSTRACE(( "LOCK %d now %d\n", pFile->h, pFile->locktype ));
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int os2CheckReservedLock( sqlite3_file *id, int *pOut ){
  int r = 0;
  os2File *pFile = (os2File*)id;
  assert( pFile!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    r = 1;
    OSTRACE(( "TEST WR-LOCK %d %d (local)\n", pFile->h, r ));
  }else{
    FILELOCK  LockArea,
              UnlockArea;
    APIRET rc = NO_ERROR;
    memset(&LockArea, 0, sizeof(LockArea));
    memset(&UnlockArea, 0, sizeof(UnlockArea));
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "TEST WR-LOCK %d lock reserved byte rc=%d\n", pFile->h, rc ));
    if( rc == NO_ERROR ){
      APIRET rcu = NO_ERROR; /* return code for unlocking */
      LockArea.lOffset = 0L;
      LockArea.lRange = 0L;
      UnlockArea.lOffset = RESERVED_BYTE;
      UnlockArea.lRange = 1L;
      rcu = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
      OSTRACE(( "TEST WR-LOCK %d unlock reserved byte r=%d\n", pFile->h, rcu ));
    }
    r = !(rc == NO_ERROR);
    OSTRACE(( "TEST WR-LOCK %d %d (remote)\n", pFile->h, r ));
  }
  *pOut = r;
  return SQLITE_OK;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
**
** It is not possible for this routine to fail if the second argument
** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
** might return SQLITE_IOERR;
*/
static int os2Unlock( sqlite3_file *id, int locktype ){
  int type;
  os2File *pFile = (os2File*)id;
  APIRET rc = SQLITE_OK;
  APIRET res = NO_ERROR;
  FILELOCK  LockArea,
            UnlockArea;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype ));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = SHARED_FIRST;
    UnlockArea.lRange = SHARED_SIZE;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d exclusive lock res=%d\n", pFile->h, res ));
    if( locktype==SHARED_LOCK && getReadLock(pFile) != NO_ERROR ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      OSTRACE(( "UNLOCK %d to %d getReadLock() failed\n", pFile->h, locktype ));
      rc = SQLITE_IOERR_UNLOCK;
    }
  }
  if( type>=RESERVED_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = RESERVED_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d reserved res=%d\n", pFile->h, res ));
  }
  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
    res = unlockReadLock(pFile);
    OSTRACE(( "UNLOCK %d is %d want %d res=%d\n",
              pFile->h, type, locktype, res ));
  }
  if( type>=PENDING_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d pending res=%d\n", pFile->h, res ));
  }
  pFile->locktype = locktype;
  OSTRACE(( "UNLOCK %d now %d\n", pFile->h, pFile->locktype ));
  return rc;
}

/*
** Control and query of the open file handle.
*/
static int os2FileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {
      *(int*)pArg = ((os2File*)id)->locktype;
      OSTRACE(( "FCNTL_LOCKSTATE %d lock=%d\n",
                ((os2File*)id)->h, ((os2File*)id)->locktype ));
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_CHUNK_SIZE: {
      ((os2File*)id)->szChunk = *(int*)pArg;
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_SIZE_HINT: {
      sqlite3_int64 sz = *(sqlite3_int64*)pArg;
      SimulateIOErrorBenign(1);
      os2Truncate(id, sz);
      SimulateIOErrorBenign(0);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_SYNC_OMITTED: {
      return SQLITE_OK;
    }
  }
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for
** the specified file. This is almost always 512 bytes, but may be
** larger for some devices.
**
** SQLite code assumes this function cannot fail. It also assumes that
** if two files are created in the same file-system directory (i.e.
** a database and its journal file) that the sector size will be the
** same for both.
*/
static int os2SectorSize(sqlite3_file *id){
  UNUSED_PARAMETER(id);
  return SQLITE_DEFAULT_SECTOR_SIZE;
}

/*
** Return a vector of device characteristics.
*/
static int os2DeviceCharacteristics(sqlite3_file *id){
  UNUSED_PARAMETER(id);
  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN;
}


/*
** Character set conversion objects used by conversion routines.
*/
static UconvObject ucUtf8 = NULL; /* convert between UTF-8 and UCS-2 */
static UconvObject uclCp = NULL;  /* convert between local codepage and UCS-2 */

/*
** Helper function to initialize the conversion objects from and to UTF-8.
*/
static void initUconvObjects( void ){
  if( UniCreateUconvObject( UTF_8, &ucUtf8 ) != ULS_SUCCESS )
    ucUtf8 = NULL;
  if ( UniCreateUconvObject( (UniChar *)L"@path=yes", &uclCp ) != ULS_SUCCESS )
    uclCp = NULL;
}

/*
** Helper function to free the conversion objects from and to UTF-8.
*/
static void freeUconvObjects( void ){
  if ( ucUtf8 )
    UniFreeUconvObject( ucUtf8 );
  if ( uclCp )
    UniFreeUconvObject( uclCp );
  ucUtf8 = NULL;
  uclCp = NULL;
}

/*
** Helper function to convert UTF-8 filenames to local OS/2 codepage.
** The two-step process: first convert the incoming UTF-8 string
** into UCS-2 and then from UCS-2 to the current codepage.
** The returned char pointer has to be freed.
*/
static char *convertUtf8PathToCp( const char *in ){
  UniChar tempPath[CCHMAXPATH];
  char *out = (char *)calloc( CCHMAXPATH, 1 );

  if( !out )
    return NULL;

  if( !ucUtf8 || !uclCp )
    initUconvObjects();

  /* determine string for the conversion of UTF-8 which is CP1208 */
  if( UniStrToUcs( ucUtf8, tempPath, (char *)in, CCHMAXPATH ) != ULS_SUCCESS )
    return out; /* if conversion fails, return the empty string */

  /* conversion for current codepage which can be used for paths */
  UniStrFromUcs( uclCp, out, tempPath, CCHMAXPATH );

  return out;
}

/*
** Helper function to convert filenames from local codepage to UTF-8.
** The two-step process: first convert the incoming codepage-specific
** string into UCS-2 and then from UCS-2 to the codepage of UTF-8.
** The returned char pointer has to be freed.
**
** This function is non-static to be able to use this in shell.c and
** similar applications that take command line arguments.
*/
char *convertCpPathToUtf8( const char *in ){
  UniChar tempPath[CCHMAXPATH];
  char *out = (char *)calloc( CCHMAXPATH, 1 );

  if( !out )
    return NULL;

  if( !ucUtf8 || !uclCp )
    initUconvObjects();

  /* conversion for current codepage which can be used for paths */
  if( UniStrToUcs( uclCp, tempPath, (char *)in, CCHMAXPATH ) != ULS_SUCCESS )
    return out; /* if conversion fails, return the empty string */

  /* determine string for the conversion of UTF-8 which is CP1208 */
  UniStrFromUcs( ucUtf8, out, tempPath, CCHMAXPATH );

  return out;
}


#ifndef SQLITE_OMIT_WAL

/*
** Use main database file for interprocess locking. If un-defined
** a separate file is created for this purpose. The file will be
** used only to set file locks. There will be no data written to it.
*/
#define SQLITE_OS2_NO_WAL_LOCK_FILE     

#if 0
static void _ERR_TRACE( const char *fmt, ... ) {
  va_list  ap;
  va_start(ap, fmt);
  vfprintf(stderr, fmt, ap);
  fflush(stderr);
}
#define ERR_TRACE(rc, msg)        \
        if( (rc) != SQLITE_OK ) _ERR_TRACE msg;
#else
#define ERR_TRACE(rc, msg)
#endif

/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect os2ShmNodeList.
**
** Function os2ShmMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   os2ShmEnterMutex()
**     assert( os2ShmMutexHeld() );
**   os2ShmLeaveMutex()
*/
static void os2ShmEnterMutex(void){
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
static void os2ShmLeaveMutex(void){
  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#ifdef SQLITE_DEBUG
static int os2ShmMutexHeld(void) {
  return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
int GetCurrentProcessId(void) {
  PPIB pib;
  DosGetInfoBlocks(NULL, &pib);
  return (int)pib->pib_ulpid;
}
#endif

/*
** Object used to represent a the shared memory area for a single log file.
** When multiple threads all reference the same log-summary, each thread has
** its own os2File object, but they all point to a single instance of this 
** object.  In other words, each log-summary is opened only once per process.
**
** os2ShmMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
**
**      nRef
**      pNext 
**
** The following fields are read-only after the object is created:
** 
**      szRegion
**      hLockFile
**      shmBaseName
**
** Either os2ShmNode.mutex must be held or os2ShmNode.nRef==0 and
** os2ShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
*/
struct os2ShmNode {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  os2ShmNode *pNext;         /* Next in list of all os2ShmNode objects */

  int szRegion;              /* Size of shared-memory regions */

  int nRegion;               /* Size of array apRegion */
  void **apRegion;           /* Array of pointers to shared-memory regions */

  int nRef;                  /* Number of os2ShmLink objects pointing to this */
  os2ShmLink *pFirst;        /* First os2ShmLink object pointing to this */

  HFILE hLockFile;           /* File used for inter-process memory locking */
  char shmBaseName[1];       /* Name of the memory object !!! must last !!! */
};


/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection.
**
** The following fields are initialized when this object is created and
** are read-only thereafter:
**
**    os2Shm.pShmNode
**    os2Shm.id
**
** All other fields are read/write.  The os2Shm.pShmNode->mutex must be held
** while accessing any read/write fields.
*/
struct os2ShmLink {
  os2ShmNode *pShmNode;      /* The underlying os2ShmNode object */
  os2ShmLink *pNext;         /* Next os2Shm with the same os2ShmNode */
  u32 sharedMask;            /* Mask of shared locks held */
  u32 exclMask;              /* Mask of exclusive locks held */
#ifdef SQLITE_DEBUG
  u8 id;                     /* Id of this connection with its os2ShmNode */
#endif
};


/*
** A global list of all os2ShmNode objects.
**
** The os2ShmMutexHeld() must be true while reading or writing this list.
*/
static os2ShmNode *os2ShmNodeList = NULL;

/*
** Constants used for locking
*/
#ifdef  SQLITE_OS2_NO_WAL_LOCK_FILE
#define OS2_SHM_BASE   (PENDING_BYTE + 0x10000)         /* first lock byte */
#else
#define OS2_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
#endif

#define OS2_SHM_DMS    (OS2_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */

/*
** Apply advisory locks for all n bytes beginning at ofst.
*/
#define _SHM_UNLCK  1   /* no lock */
#define _SHM_RDLCK  2   /* shared lock, no wait */
#define _SHM_WRLCK  3   /* exlusive lock, no wait */
#define _SHM_WRLCK_WAIT 4 /* exclusive lock, wait */
static int os2ShmSystemLock(
  os2ShmNode *pNode,    /* Apply locks to this open shared-memory segment */
  int lockType,         /* _SHM_UNLCK, _SHM_RDLCK, _SHM_WRLCK or _SHM_WRLCK_WAIT */
  int ofst,             /* Offset to first byte to be locked/unlocked */
  int nByte             /* Number of bytes to lock or unlock */
){
  APIRET rc;
  FILELOCK area;
  ULONG mode, timeout;

  /* Access to the os2ShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pNode->mutex) || pNode->nRef==0 );

  mode = 1;     /* shared lock */
  timeout = 0;  /* no wait */
  area.lOffset = ofst;
  area.lRange = nByte;

  switch( lockType ) {
    case _SHM_WRLCK_WAIT:
      timeout = (ULONG)-1;      /* wait forever */
    case _SHM_WRLCK:
      mode = 0;                 /* exclusive lock */
    case _SHM_RDLCK:
      rc = DosSetFileLocks(pNode->hLockFile, 
                           NULL, &area, timeout, mode);
      break;
    /* case _SHM_UNLCK: */
    default:
      rc = DosSetFileLocks(pNode->hLockFile, 
                           &area, NULL, 0, 0);
      break;
  }
                          
  OSTRACE(("SHM-LOCK %d %s %s 0x%08lx\n", 
           pNode->hLockFile,
           rc==SQLITE_OK ? "ok" : "failed",
           lockType==_SHM_UNLCK ? "Unlock" : "Lock",
           rc));

  ERR_TRACE(rc, ("os2ShmSystemLock: %d %s\n", rc, pNode->shmBaseName))

  return ( rc == 0 ) ?  SQLITE_OK : SQLITE_BUSY;
}

/*
** Find an os2ShmNode in global list or allocate a new one, if not found.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static int os2OpenSharedMemory( os2File *fd, int szRegion ) {
  os2ShmLink *pLink;
  os2ShmNode *pNode;
  int cbShmName, rc = SQLITE_OK;
  char shmName[CCHMAXPATH + 30];
#ifndef SQLITE_OS2_NO_WAL_LOCK_FILE
  ULONG action;
#endif
  
  /* We need some additional space at the end to append the region number */
  cbShmName = sprintf(shmName, "\\SHAREMEM\\%s", fd->zFullPathCp );
  if( cbShmName >= CCHMAXPATH-8 )
    return SQLITE_IOERR_SHMOPEN; 

  /* Replace colon in file name to form a valid shared memory name */
  shmName[10+1] = '!';

  /* Allocate link object (we free it later in case of failure) */
  pLink = sqlite3_malloc( sizeof(*pLink) );
  if( !pLink )
    return SQLITE_NOMEM;

  /* Access node list */
  os2ShmEnterMutex();

  /* Find node by it's shared memory base name */
  for( pNode = os2ShmNodeList; 
       pNode && stricmp(shmName, pNode->shmBaseName) != 0; 
       pNode = pNode->pNext )   ;

  /* Not found: allocate a new node */
  if( !pNode ) {
    pNode = sqlite3_malloc( sizeof(*pNode) + cbShmName );
    if( pNode ) {
      memset(pNode, 0, sizeof(*pNode) );
      pNode->szRegion = szRegion;
      pNode->hLockFile = (HFILE)-1;      
      strcpy(pNode->shmBaseName, shmName);

#ifdef SQLITE_OS2_NO_WAL_LOCK_FILE
      if( DosDupHandle(fd->h, &pNode->hLockFile) != 0 ) {
#else
      sprintf(shmName, "%s-lck", fd->zFullPathCp);
      if( DosOpen((PSZ)shmName, &pNode->hLockFile, &action, 0, FILE_NORMAL, 
                  OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_CREATE_IF_NEW,
                  OPEN_ACCESS_READWRITE | OPEN_SHARE_DENYNONE | 
                  OPEN_FLAGS_NOINHERIT | OPEN_FLAGS_FAIL_ON_ERROR,
                  NULL) != 0 ) {
#endif
        sqlite3_free(pNode);  
        rc = SQLITE_IOERR;
      } else {
        pNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
        if( !pNode->mutex ) {
          sqlite3_free(pNode);  
          rc = SQLITE_NOMEM;
        }
      }   
    } else {
      rc = SQLITE_NOMEM;
    }
    
    if( rc == SQLITE_OK ) {
      pNode->pNext = os2ShmNodeList;
      os2ShmNodeList = pNode;
    } else {
      pNode = NULL;
    }
  } else if( pNode->szRegion != szRegion ) {
    rc = SQLITE_IOERR_SHMSIZE;
    pNode = NULL;
  }

  if( pNode ) {
    sqlite3_mutex_enter(pNode->mutex);

    memset(pLink, 0, sizeof(*pLink));

    pLink->pShmNode = pNode;
    pLink->pNext = pNode->pFirst;
    pNode->pFirst = pLink;
    pNode->nRef++;

    fd->pShmLink = pLink;

    sqlite3_mutex_leave(pNode->mutex);
    
  } else {
    /* Error occured. Free our link object. */
    sqlite3_free(pLink);  
  }

  os2ShmLeaveMutex();

  ERR_TRACE(rc, ("os2OpenSharedMemory: %d  %s\n", rc, fd->zFullPathCp))  
  
  return rc;
}

/*
** Purge the os2ShmNodeList list of all entries with nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void os2PurgeShmNodes( int deleteFlag ) {
  os2ShmNode *pNode;
  os2ShmNode **ppNode;

  os2ShmEnterMutex();
  
  ppNode = &os2ShmNodeList;

  while( *ppNode ) {
    pNode = *ppNode;

    if( pNode->nRef == 0 ) {
      *ppNode = pNode->pNext;   
     
      if( pNode->apRegion ) {
        /* Prevent other processes from resizing the shared memory */
        os2ShmSystemLock(pNode, _SHM_WRLCK_WAIT, OS2_SHM_DMS, 1);

        while( pNode->nRegion-- ) {
#ifdef SQLITE_DEBUG
          int rc = 
#endif          
          DosFreeMem(pNode->apRegion[pNode->nRegion]);

          OSTRACE(("SHM-PURGE pid-%d unmap region=%d %s\n",
                  (int)GetCurrentProcessId(), pNode->nRegion,
                  rc == 0 ? "ok" : "failed"));
        }

        /* Allow other processes to resize the shared memory */
        os2ShmSystemLock(pNode, _SHM_UNLCK, OS2_SHM_DMS, 1);

        sqlite3_free(pNode->apRegion);
      }  

      DosClose(pNode->hLockFile);
      
#ifndef SQLITE_OS2_NO_WAL_LOCK_FILE
      if( deleteFlag ) {
         char fileName[CCHMAXPATH];
         /* Skip "\\SHAREMEM\\" */
         sprintf(fileName, "%s-lck", pNode->shmBaseName + 10);
         /* restore colon */
         fileName[1] = ':';
         
         DosForceDelete(fileName); 
      }
#endif

      sqlite3_mutex_free(pNode->mutex);

      sqlite3_free(pNode);
      
    } else {
      ppNode = &pNode->pNext;
    }
  } 

  os2ShmLeaveMutex();
}

/*
** This function is called to obtain a pointer to region iRegion of the
** shared-memory associated with the database file id. Shared-memory regions
** are numbered starting from zero. Each shared-memory region is szRegion
** bytes in size.
**
** If an error occurs, an error code is returned and *pp is set to NULL.
**
** Otherwise, if the bExtend parameter is 0 and the requested shared-memory
** region has not been allocated (by any client, including one running in a
** separate process), then *pp is set to NULL and SQLITE_OK returned. If
** bExtend is non-zero and the requested shared-memory region has not yet
** been allocated, it is allocated by this function.
**
** If the shared-memory region has already been allocated or is allocated by
** this call as described above, then it is mapped into this processes
** address space (if it is not already), *pp is set to point to the mapped
** memory and SQLITE_OK returned.
*/
static int os2ShmMap(
  sqlite3_file *id,               /* Handle open on database file */
  int iRegion,                    /* Region to retrieve */
  int szRegion,                   /* Size of regions */
  int bExtend,                    /* True to extend block if necessary */
  void volatile **pp              /* OUT: Mapped memory */
){
  PVOID pvTemp;
  void **apRegion;
  os2ShmNode *pNode;
  int n, rc = SQLITE_OK;
  char shmName[CCHMAXPATH];
  os2File *pFile = (os2File*)id;
  
  *pp = NULL;

  if( !pFile->pShmLink )
    rc = os2OpenSharedMemory( pFile, szRegion );
  
  if( rc == SQLITE_OK ) {
    pNode = pFile->pShmLink->pShmNode ;
    
    sqlite3_mutex_enter(pNode->mutex);
    
    assert( szRegion==pNode->szRegion );

    /* Unmapped region ? */
    if( iRegion >= pNode->nRegion ) {
      /* Prevent other processes from resizing the shared memory */
      os2ShmSystemLock(pNode, _SHM_WRLCK_WAIT, OS2_SHM_DMS, 1);

      apRegion = sqlite3_realloc(
        pNode->apRegion, (iRegion + 1) * sizeof(apRegion[0]));

      if( apRegion ) {
        pNode->apRegion = apRegion;

        while( pNode->nRegion <= iRegion ) {
          sprintf(shmName, "%s-%u", 
                  pNode->shmBaseName, pNode->nRegion);

          if( DosGetNamedSharedMem(&pvTemp, (PSZ)shmName, 
                PAG_READ | PAG_WRITE) != NO_ERROR ) {
            if( !bExtend )
              break;

            if( DosAllocSharedMem(&pvTemp, (PSZ)shmName, szRegion,
                  PAG_READ | PAG_WRITE | PAG_COMMIT | OBJ_ANY) != NO_ERROR && 
                DosAllocSharedMem(&pvTemp, (PSZ)shmName, szRegion,
                  PAG_READ | PAG_WRITE | PAG_COMMIT) != NO_ERROR ) { 
              rc = SQLITE_NOMEM;
              break;
            }
          }

          apRegion[pNode->nRegion++] = pvTemp;
        }

        /* zero out remaining entries */ 
        for( n = pNode->nRegion; n <= iRegion; n++ )
          pNode->apRegion[n] = NULL;

        /* Return this region (maybe zero) */
        *pp = pNode->apRegion[iRegion];
      } else {
        rc = SQLITE_NOMEM;
      }

      /* Allow other processes to resize the shared memory */
      os2ShmSystemLock(pNode, _SHM_UNLCK, OS2_SHM_DMS, 1);
      
    } else {
      /* Region has been mapped previously */
      *pp = pNode->apRegion[iRegion];
    }

    sqlite3_mutex_leave(pNode->mutex);
  } 

  ERR_TRACE(rc, ("os2ShmMap: %s iRgn = %d, szRgn = %d, bExt = %d : %d\n", 
                 pFile->zFullPathCp, iRegion, szRegion, bExtend, rc))
          
  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying
** storage if deleteFlag is true.
**
** If there is no shared memory associated with the connection then this
** routine is a harmless no-op.
*/
static int os2ShmUnmap(
  sqlite3_file *id,               /* The underlying database file */
  int deleteFlag                  /* Delete shared-memory if true */
){
  os2File *pFile = (os2File*)id;
  os2ShmLink *pLink = pFile->pShmLink;
  
  if( pLink ) {
    int nRef = -1;
    os2ShmLink **ppLink;
    os2ShmNode *pNode = pLink->pShmNode;

    sqlite3_mutex_enter(pNode->mutex);
    
    for( ppLink = &pNode->pFirst;
         *ppLink && *ppLink != pLink;
         ppLink = &(*ppLink)->pNext )   ;
         
    assert(*ppLink);

    if( *ppLink ) {
      *ppLink = pLink->pNext;
      nRef = --pNode->nRef;
    } else {
      ERR_TRACE(1, ("os2ShmUnmap: link not found ! %s\n", 
                    pNode->shmBaseName))
    }
    
    pFile->pShmLink = NULL;
    sqlite3_free(pLink);

    sqlite3_mutex_leave(pNode->mutex);
    
    if( nRef == 0 )
      os2PurgeShmNodes( deleteFlag );
  }

  return SQLITE_OK;
}

/*
** Change the lock state for a shared-memory segment.
**
** Note that the relationship between SHAREd and EXCLUSIVE locks is a little
** different here than in posix.  In xShmLock(), one can go from unlocked
** to shared and back or from unlocked to exclusive and back.  But one may
** not go from shared to exclusive or from exclusive to shared.
*/
static int os2ShmLock(
  sqlite3_file *id,          /* 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 */
){
  u32 mask;                             /* Mask of locks to take or release */
  int rc = SQLITE_OK;                   /* Result code */
  os2File *pFile = (os2File*)id;
  os2ShmLink *p = pFile->pShmLink;      /* The shared memory being locked */
  os2ShmLink *pX;                       /* For looping over all siblings */
  os2ShmNode *pShmNode = p->pShmNode;   /* Our node */
  
  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 );

  mask = (u32)((1U<<(ofst+n)) - (1U<<ofst));
  assert( n>1 || mask==(1<<ofst) );


  sqlite3_mutex_enter(pShmNode->mutex);

  if( flags & SQLITE_SHM_UNLOCK ){
    u32 allMask = 0; /* Mask of locks held by siblings */

    /* See if any siblings hold this same lock */
    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
      if( pX==p ) continue;
      assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
      allMask |= pX->sharedMask;
    }

    /* Unlock the system-level locks */
    if( (mask & allMask)==0 ){
      rc = os2ShmSystemLock(pShmNode, _SHM_UNLCK, ofst+OS2_SHM_BASE, n);
    }else{
      rc = SQLITE_OK;
    }

    /* Undo the local locks */
    if( rc==SQLITE_OK ){
      p->exclMask &= ~mask;
      p->sharedMask &= ~mask;
    } 
  }else if( flags & SQLITE_SHM_SHARED ){
    u32 allShared = 0;  /* Union of locks held by connections other than "p" */

    /* Find out which shared locks are already held by sibling connections.
    ** If any sibling already holds an exclusive lock, go ahead and return
    ** SQLITE_BUSY.
    */
    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
      if( (pX->exclMask & mask)!=0 ){
        rc = SQLITE_BUSY;
        break;
      }
      allShared |= pX->sharedMask;
    }

    /* Get shared locks at the system level, if necessary */
    if( rc==SQLITE_OK ){
      if( (allShared & mask)==0 ){
        rc = os2ShmSystemLock(pShmNode, _SHM_RDLCK, ofst+OS2_SHM_BASE, n);
      }else{
        rc = SQLITE_OK;
      }
    }

    /* Get the local shared locks */
    if( rc==SQLITE_OK ){
      p->sharedMask |= mask;
    }
  }else{
    /* Make sure no sibling connections hold locks that will block this
    ** lock.  If any do, return SQLITE_BUSY right away.
    */
    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
      if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){
        rc = SQLITE_BUSY;
        break;
      }
    }
  
    /* Get the exclusive locks at the system level.  Then if successful
    ** also mark the local connection as being locked.
    */
    if( rc==SQLITE_OK ){
      rc = os2ShmSystemLock(pShmNode, _SHM_WRLCK, ofst+OS2_SHM_BASE, n);
      if( rc==SQLITE_OK ){
        assert( (p->sharedMask & mask)==0 );
        p->exclMask |= mask;
      }
    }
  }

  sqlite3_mutex_leave(pShmNode->mutex);
  
  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x %s\n",
           p->id, (int)GetCurrentProcessId(), p->sharedMask, p->exclMask,
           rc ? "failed" : "ok"));

  ERR_TRACE(rc, ("os2ShmLock: ofst = %d, n = %d, flags = 0x%x -> %d \n", 
                 ofst, n, flags, rc))
                  
  return rc; 
}

/*
** Implement a memory barrier or memory fence on shared memory.
**
** All loads and stores begun before the barrier must complete before
** any load or store begun after the barrier.
*/
static void os2ShmBarrier(
  sqlite3_file *id                /* Database file holding the shared memory */
){
  UNUSED_PARAMETER(id);
  os2ShmEnterMutex();
  os2ShmLeaveMutex();
}

#else
# define os2ShmMap     0
# define os2ShmLock    0
# define os2ShmBarrier 0
# define os2ShmUnmap   0
#endif /* #ifndef SQLITE_OMIT_WAL */


/*
** This vector defines all the methods that can operate on an
** sqlite3_file for os2.
*/
static const sqlite3_io_methods os2IoMethod = {
  2,                              /* iVersion */
  os2Close,                       /* xClose */
  os2Read,                        /* xRead */
  os2Write,                       /* xWrite */
  os2Truncate,                    /* xTruncate */
  os2Sync,                        /* xSync */
  os2FileSize,                    /* xFileSize */
  os2Lock,                        /* xLock */
  os2Unlock,                      /* xUnlock */
  os2CheckReservedLock,           /* xCheckReservedLock */
  os2FileControl,                 /* xFileControl */
  os2SectorSize,                  /* xSectorSize */
  os2DeviceCharacteristics,       /* xDeviceCharacteristics */
  os2ShmMap,                      /* xShmMap */
  os2ShmLock,                     /* xShmLock */
  os2ShmBarrier,                  /* xShmBarrier */
  os2ShmUnmap                     /* xShmUnmap */
};


/***************************************************************************
** Here ends the I/O methods that form the sqlite3_io_methods object.
**
** The next block of code implements the VFS methods.
****************************************************************************/

/*
** Create a temporary file name in zBuf.  zBuf must be big enough to
** hold at pVfs->mxPathname characters.
*/
static int getTempname(int nBuf, char *zBuf ){
  static const char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  int i, j;
  PSZ zTempPathCp;      
  char zTempPath[CCHMAXPATH];
  ULONG ulDriveNum, ulDriveMap;
  
  /* 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 );

  if( sqlite3_temp_directory ) {
    sqlite3_snprintf(CCHMAXPATH-30, zTempPath, "%s", sqlite3_temp_directory);
  } else if( DosScanEnv( (PSZ)"TEMP",   &zTempPathCp ) == NO_ERROR ||
             DosScanEnv( (PSZ)"TMP",    &zTempPathCp ) == NO_ERROR ||
             DosScanEnv( (PSZ)"TMPDIR", &zTempPathCp ) == NO_ERROR ) {
    char *zTempPathUTF = convertCpPathToUtf8( (char *)zTempPathCp );
    sqlite3_snprintf(CCHMAXPATH-30, zTempPath, "%s", zTempPathUTF);
    free( zTempPathUTF );
  } else if( DosQueryCurrentDisk( &ulDriveNum, &ulDriveMap ) == NO_ERROR ) {
    zTempPath[0] = (char)('A' + ulDriveNum - 1);
    zTempPath[1] = ':'; 
    zTempPath[2] = '\0'; 
  } else {
    zTempPath[0] = '\0'; 
  }
  
  /* Strip off a trailing slashes or backslashes, otherwise we would get *
   * multiple (back)slashes which causes DosOpen() to fail.              *
   * Trailing spaces are not allowed, either.                            */
  j = sqlite3Strlen30(zTempPath);
  while( j > 0 && ( zTempPath[j-1] == '\\' || zTempPath[j-1] == '/' || 
                    zTempPath[j-1] == ' ' ) ){
    j--;
  }
  zTempPath[j] = '\0';
  
  /* We use 20 bytes to randomize the name */
  sqlite3_snprintf(nBuf-22, zBuf,
                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness( 20, &zBuf[j] );
  for( i = 0; i < 20; i++, j++ ){
    zBuf[j] = zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;

  OSTRACE(( "TEMP FILENAME: %s\n", zBuf ));
  return SQLITE_OK;
}


/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zFull[].  zFull[] will be at least pVfs->mxPathname
** bytes in size.
*/
static int os2FullPathname(
  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 */
){
  char *zRelativeCp = convertUtf8PathToCp( zRelative );
  char zFullCp[CCHMAXPATH] = "\0";
  char *zFullUTF;
  APIRET rc = DosQueryPathInfo( (PSZ)zRelativeCp, FIL_QUERYFULLNAME, 
                                zFullCp, CCHMAXPATH );
  free( zRelativeCp );
  zFullUTF = convertCpPathToUtf8( zFullCp );
  sqlite3_snprintf( nFull, zFull, zFullUTF );
  free( zFullUTF );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
}


/*
** Open a file.
*/
static int os2Open(
  sqlite3_vfs *pVfs,            /* Not used */
  const char *zName,            /* Name of the file (UTF-8) */
  sqlite3_file *id,             /* Write the SQLite file handle here */
  int flags,                    /* Open mode flags */
  int *pOutFlags                /* Status return flags */
){
  HFILE h;
  ULONG ulOpenFlags = 0;
  ULONG ulOpenMode = 0;
  ULONG ulAction = 0;
  ULONG rc;
  os2File *pFile = (os2File*)id;
  const char *zUtf8Name = zName;
  char *zNameCp;
  char  zTmpname[CCHMAXPATH];

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
  int isCreate     = (flags & SQLITE_OPEN_CREATE);
  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
#ifndef NDEBUG
  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
  int eType        = (flags & 0xFFFFFF00);
  int isOpenJournal = (isCreate && (
        eType==SQLITE_OPEN_MASTER_JOURNAL 
     || eType==SQLITE_OPEN_MAIN_JOURNAL 
     || eType==SQLITE_OPEN_WAL
  ));
#endif

  UNUSED_PARAMETER(pVfs);
  assert( id!=0 );

  /* Check the following statements are true: 
  **
  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
  **   (b) if CREATE is set, then READWRITE must also be set, and
  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
  */
  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
  assert(isCreate==0 || isReadWrite);
  assert(isExclusive==0 || isCreate);
  assert(isDelete==0 || isCreate);

  /* The main DB, main journal, WAL file and master journal are never 
  ** automatically deleted. Nor are they ever temporary files.  */
  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MASTER_JOURNAL );
  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );

  /* Assert that the upper layer has set one of the "file-type" flags. */
  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB 
       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL 
       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_MASTER_JOURNAL 
       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
  );

  memset( pFile, 0, sizeof(*pFile) );
  pFile->h = (HFILE)-1;

  /* If the second argument to this function is NULL, generate a 
  ** temporary file name to use 
  */
  if( !zUtf8Name ){
    assert(isDelete && !isOpenJournal);
    rc = getTempname(CCHMAXPATH, zTmpname);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    zUtf8Name = zTmpname;
  }

  if( isReadWrite ){
    ulOpenMode |= OPEN_ACCESS_READWRITE;
  }else{
    ulOpenMode |= OPEN_ACCESS_READONLY;
  }

  /* Open in random access mode for possibly better speed.  Allow full
  ** sharing because file locks will provide exclusive access when needed.
  ** The handle should not be inherited by child processes and we don't 
  ** want popups from the critical error handler.
  */
  ulOpenMode |= OPEN_FLAGS_RANDOM | OPEN_SHARE_DENYNONE | 
                OPEN_FLAGS_NOINHERIT | OPEN_FLAGS_FAIL_ON_ERROR;

  /* SQLITE_OPEN_EXCLUSIVE is used to make sure that a new file is 
  ** created. SQLite doesn't use it to indicate "exclusive access" 
  ** as it is usually understood.
  */
  if( isExclusive ){
    /* Creates a new file, only if it does not already exist. */
    /* If the file exists, it fails. */
    ulOpenFlags |= OPEN_ACTION_CREATE_IF_NEW | OPEN_ACTION_FAIL_IF_EXISTS;
  }else if( isCreate ){
    /* Open existing file, or create if it doesn't exist */
    ulOpenFlags |= OPEN_ACTION_CREATE_IF_NEW | OPEN_ACTION_OPEN_IF_EXISTS;
  }else{
    /* Opens a file, only if it exists. */
    ulOpenFlags |= OPEN_ACTION_FAIL_IF_NEW | OPEN_ACTION_OPEN_IF_EXISTS;
  }

  zNameCp = convertUtf8PathToCp( zUtf8Name );
  rc = DosOpen( (PSZ)zNameCp,
                &h,
                &ulAction,
                0L,
                FILE_NORMAL,
                ulOpenFlags,
                ulOpenMode,
                (PEAOP2)NULL );
  free( zNameCp );

  if( rc != NO_ERROR ){
    OSTRACE(( "OPEN Invalid handle rc=%d: zName=%s, ulAction=%#lx, ulFlags=%#lx, ulMode=%#lx\n",
              rc, zUtf8Name, ulAction, ulOpenFlags, ulOpenMode ));

    if( isReadWrite ){
      return os2Open( pVfs, zName, id,
                      ((flags|SQLITE_OPEN_READONLY)&~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)),
                      pOutFlags );
    }else{
      return SQLITE_CANTOPEN;
    }
  }

  if( pOutFlags ){
    *pOutFlags = isReadWrite ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY;
  }

  os2FullPathname( pVfs, zUtf8Name, sizeof( zTmpname ), zTmpname );
  pFile->zFullPathCp = convertUtf8PathToCp( zTmpname );
  pFile->pMethod = &os2IoMethod;
  pFile->flags = flags;
  pFile->h = h;

  OpenCounter(+1);
  OSTRACE(( "OPEN %d pOutFlags=%d\n", pFile->h, pOutFlags ));
  return SQLITE_OK;
}

/*
** Delete the named file.
*/
static int os2Delete(
  sqlite3_vfs *pVfs,                     /* Not used on os2 */
  const char *zFilename,                 /* Name of file to delete */
  int syncDir                            /* Not used on os2 */
){
  APIRET rc;
  char *zFilenameCp;
  SimulateIOError( return SQLITE_IOERR_DELETE );
  zFilenameCp = convertUtf8PathToCp( zFilename );
  rc = DosDelete( (PSZ)zFilenameCp );
  free( zFilenameCp );
  OSTRACE(( "DELETE \"%s\"\n", zFilename ));
  return (rc == NO_ERROR ||
          rc == ERROR_FILE_NOT_FOUND ||
          rc == ERROR_PATH_NOT_FOUND ) ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/
static int os2Access(
  sqlite3_vfs *pVfs,        /* Not used on os2 */
  const char *zFilename,    /* Name of file to check */
  int flags,                /* Type of test to make on this file */
  int *pOut                 /* Write results here */
){
  APIRET rc;
  FILESTATUS3 fsts3ConfigInfo;
  char *zFilenameCp;

  UNUSED_PARAMETER(pVfs);
  SimulateIOError( return SQLITE_IOERR_ACCESS; );
  
  zFilenameCp = convertUtf8PathToCp( zFilename );
  rc = DosQueryPathInfo( (PSZ)zFilenameCp, FIL_STANDARD,
                         &fsts3ConfigInfo, sizeof(FILESTATUS3) );
  free( zFilenameCp );
  OSTRACE(( "ACCESS fsts3ConfigInfo.attrFile=%d flags=%d rc=%d\n",
            fsts3ConfigInfo.attrFile, flags, rc ));

  switch( flags ){
    case SQLITE_ACCESS_EXISTS:
      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
      ** as if it does not exist.
      */
      if( fsts3ConfigInfo.cbFile == 0 ) 
        rc = ERROR_FILE_NOT_FOUND;
      break;
    case SQLITE_ACCESS_READ:
      break;
    case SQLITE_ACCESS_READWRITE:
      if( fsts3ConfigInfo.attrFile & FILE_READONLY )
        rc = ERROR_ACCESS_DENIED;
      break;
    default:
      rc = ERROR_FILE_NOT_FOUND;
      assert( !"Invalid flags argument" );
  }

  *pOut = (rc == NO_ERROR);
  OSTRACE(( "ACCESS %s flags %d: rc=%d\n", zFilename, flags, *pOut ));

  return SQLITE_OK;
}


#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
static void *os2DlOpen(sqlite3_vfs *pVfs, const char *zFilename){
  HMODULE hmod;
  APIRET rc;
  char *zFilenameCp = convertUtf8PathToCp(zFilename);
  rc = DosLoadModule(NULL, 0, (PSZ)zFilenameCp, &hmod);
  free(zFilenameCp);
  return rc != NO_ERROR ? 0 : (void*)hmod;
}
/*
** A no-op since the error code is returned on the DosLoadModule call.
** os2Dlopen returns zero if DosLoadModule is not successful.
*/
static void os2DlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
/* no-op */
}
static void (*os2DlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol))(void){
  PFN pfn;
  APIRET rc;
  rc = DosQueryProcAddr((HMODULE)pHandle, 0L, (PSZ)zSymbol, &pfn);
  if( rc != NO_ERROR ){
    /* if the symbol itself was not found, search again for the same
     * symbol with an extra underscore, that might be needed depending
     * on the calling convention */
    char _zSymbol[256] = "_";
    strncat(_zSymbol, zSymbol, 254);
    rc = DosQueryProcAddr((HMODULE)pHandle, 0L, (PSZ)_zSymbol, &pfn);
  }
  return rc != NO_ERROR ? 0 : (void(*)(void))pfn;
}
static void os2DlClose(sqlite3_vfs *pVfs, void *pHandle){
  DosFreeModule((HMODULE)pHandle);
}
#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
  #define os2DlOpen 0
  #define os2DlError 0
  #define os2DlSym 0
  #define os2DlClose 0
#endif


/*
** Write up to nBuf bytes of randomness into zBuf.
*/
static int os2Randomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf ){
  int n = 0;
#if defined(SQLITE_TEST)
  n = nBuf;
  memset(zBuf, 0, nBuf);
#else
  int i;                           
  PPIB ppib;
  PTIB ptib;
  DATETIME dt; 
  static unsigned c = 0;
  /* Ordered by variation probability */
  static ULONG svIdx[6] = { QSV_MS_COUNT, QSV_TIME_LOW,
                            QSV_MAXPRMEM, QSV_MAXSHMEM,
                            QSV_TOTAVAILMEM, QSV_TOTRESMEM };

  /* 8 bytes; timezone and weekday don't increase the randomness much */
  if( (int)sizeof(dt)-3 <= nBuf - n ){
    c += 0x0100;
    DosGetDateTime(&dt);
    dt.year = (USHORT)((dt.year - 1900) | c);
    memcpy(&zBuf[n], &dt, sizeof(dt)-3);
    n += sizeof(dt)-3;
  }

  /* 4 bytes; PIDs and TIDs are 16 bit internally, so combine them */
  if( (int)sizeof(ULONG) <= nBuf - n ){
    DosGetInfoBlocks(&ptib, &ppib);
    *(PULONG)&zBuf[n] = MAKELONG(ppib->pib_ulpid,
                                 ptib->tib_ptib2->tib2_ultid);
    n += sizeof(ULONG);
  }

  /* Up to 6 * 4 bytes; variables depend on the system state */
  for( i = 0; i < 6 && (int)sizeof(ULONG) <= nBuf - n; i++ ){
    DosQuerySysInfo(svIdx[i], svIdx[i], 
                    (PULONG)&zBuf[n], sizeof(ULONG));
    n += sizeof(ULONG);
  } 
#endif

  return n;
}

/*
** Sleep for a little while.  Return the amount of time slept.
** The argument is the number of microseconds we want to sleep.
** The return value is the number of microseconds of sleep actually
** requested from the underlying operating system, a number which
** might be greater than or equal to the argument, but not less
** than the argument.
*/
static int os2Sleep( sqlite3_vfs *pVfs, int microsec ){
  DosSleep( (microsec/1000) );
  return microsec;
}

/*
** The following variable, if set to a non-zero value, becomes the result
** returned from sqlite3OsCurrentTime().  This is used for testing.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_current_time = 0;
#endif

/*
** Find the current time (in Universal Coordinated Time).  Write into *piNow
** the current time and date as a Julian Day number times 86_400_000.  In
** other words, write into *piNow the number of milliseconds since the Julian
** epoch of noon in Greenwich on November 24, 4714 B.C according to the
** proleptic Gregorian calendar.
**
** On success, return 0.  Return 1 if the time and date cannot be found.
*/
static int os2CurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *piNow){
#ifdef SQLITE_TEST
  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
#endif
  int year, month, datepart, timepart;
 
  DATETIME dt;
  DosGetDateTime( &dt );

  year = dt.year;
  month = dt.month;

  /* Calculations from http://www.astro.keele.ac.uk/~rno/Astronomy/hjd.html
  ** http://www.astro.keele.ac.uk/~rno/Astronomy/hjd-0.1.c
  ** Calculate the Julian days
  */
  datepart = (int)dt.day - 32076 +
    1461*(year + 4800 + (month - 14)/12)/4 +
    367*(month - 2 - (month - 14)/12*12)/12 -
    3*((year + 4900 + (month - 14)/12)/100)/4;

  /* Time in milliseconds, hours to noon added */
  timepart = 12*3600*1000 + dt.hundredths*10 + dt.seconds*1000 +
    ((int)dt.minutes + dt.timezone)*60*1000 + dt.hours*3600*1000;

  *piNow = (sqlite3_int64)datepart*86400*1000 + timepart;
   
#ifdef SQLITE_TEST
  if( sqlite3_current_time ){
    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
  }
#endif

  UNUSED_PARAMETER(pVfs);
  return 0;
}

/*
** Find the current time (in Universal Coordinated Time).  Write the
** current time and date as a Julian Day number into *prNow and
** return 0.  Return 1 if the time and date cannot be found.
*/
static int os2CurrentTime( sqlite3_vfs *pVfs, double *prNow ){
  int rc;
  sqlite3_int64 i;
  rc = os2CurrentTimeInt64(pVfs, &i);
  if( !rc ){
    *prNow = i/86400000.0;
  }
  return rc;
}

/*
** The idea is that this function works like a combination of
** GetLastError() and FormatMessage() on windows (or errno and
** strerror_r() on unix). After an error is returned by an OS
** function, SQLite calls this function with zBuf pointing to
** a buffer of nBuf bytes. The OS layer should populate the
** buffer with a nul-terminated UTF-8 encoded error message
** describing the last IO error to have occurred within the calling
** thread.
**
** If the error message is too large for the supplied buffer,
** it should be truncated. The return value of xGetLastError
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated). If non-zero is returned,
** then it is not necessary to include the nul-terminator character
** in the output buffer.
**
** Not supplying an error message will have no adverse effect
** on SQLite. It is fine to have an implementation that never
** returns an error message:
**
**   int xGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
**     assert(zBuf[0]=='\0');
**     return 0;
**   }
**
** However if an error message is supplied, it will be incorporated
** by sqlite into the error message available to the user using
** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int os2GetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  assert(zBuf[0]=='\0');
  return 0;
}

/*
** Initialize and deinitialize the operating system interface.
*/
SQLITE_API int sqlite3_os_init(void){
  static sqlite3_vfs os2Vfs = {
    3,                 /* iVersion */
    sizeof(os2File),   /* szOsFile */
    CCHMAXPATH,        /* mxPathname */
    0,                 /* pNext */
    "os2",             /* zName */
    0,                 /* pAppData */

    os2Open,           /* xOpen */
    os2Delete,         /* xDelete */
    os2Access,         /* xAccess */
    os2FullPathname,   /* xFullPathname */
    os2DlOpen,         /* xDlOpen */
    os2DlError,        /* xDlError */
    os2DlSym,          /* xDlSym */
    os2DlClose,        /* xDlClose */
    os2Randomness,     /* xRandomness */
    os2Sleep,          /* xSleep */
    os2CurrentTime,    /* xCurrentTime */
    os2GetLastError,   /* xGetLastError */
    os2CurrentTimeInt64, /* xCurrentTimeInt64 */
    0,                 /* xSetSystemCall */
    0,                 /* xGetSystemCall */
    0                  /* xNextSystemCall */
  };
  sqlite3_vfs_register(&os2Vfs, 1);
  initUconvObjects();
/*  sqlite3OSTrace = 1; */
  return SQLITE_OK;
}
SQLITE_API int sqlite3_os_end(void){
  freeUconvObjects();
  return SQLITE_OK;
}

#endif /* SQLITE_OS_OS2 */

/************** End of os_os2.c **********************************************/
/************** Begin file os_unix.c *****************************************/
/*
** 2004 May 22
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**

    /* random NFS retry error, unless during file system support 
     * introspection, in which it actually means what it says */
    return SQLITE_BUSY;
    
  case EACCES: 
    /* EACCES is like EAGAIN during locking operations, but not any other time*/
    if( (sqliteIOErr == SQLITE_IOERR_LOCK) || 
	(sqliteIOErr == SQLITE_IOERR_UNLOCK) || 
	(sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
	(sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ){
      return SQLITE_BUSY;
    }
    /* else fall through */
  case EPERM: 
    return SQLITE_PERM;
    
  /* EDEADLK is only possible if a call to fcntl(F_SETLKW) is made. And

** set. It logs a message using sqlite3_log() containing the current value of
** errno and, if possible, the human-readable equivalent from strerror() or
** strerror_r().
**
** The first argument passed to the macro should be the error code that
** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
** The two subsequent arguments should be the name of the OS function that
** failed (e.g. "unlink", "open") and the the associated file-system path,
** if any.
*/
#define unixLogError(a,b,c)     unixLogErrorAtLine(a,b,c,__LINE__)
static int unixLogErrorAtLine(
  int errcode,                    /* SQLite error code */
  const char *zFunc,              /* Name of OS function that failed */
  const char *zPath,              /* File path associated with error */

  */ 
#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R)
  char aErr[80];
  memset(aErr, 0, sizeof(aErr));
  zErr = aErr;

  /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined,
  ** assume that the system provides the the GNU version of strerror_r() that 
  ** returns a pointer to a buffer containing the error message. That pointer 
  ** may point to aErr[], or it may point to some static storage somewhere. 
  ** Otherwise, assume that the system provides the POSIX version of 
  ** strerror_r(), which always writes an error message into aErr[].
  **
  ** If the code incorrectly assumes that it is the POSIX version that is
  ** available, the error message will often be an empty string. Not a

      lock.l_type = F_UNLCK;
      lock.l_whence = SEEK_SET;
      lock.l_start = lock.l_len = 0L;
      if( unixFileLock(pFile, &lock)==0 ){
        pInode->eFileLock = NO_LOCK;
      }else{
        rc = SQLITE_IOERR_UNLOCK;
	pFile->lastErrno = errno;
        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */
    pInode->nLock--;
    assert( pInode->nLock>=0 );
    if( pInode->nLock==0 ){
      closePendingFds(pFile);
    }
  }
	
end_unlock:
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
  return rc;
}

/*

static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  char *zLockFile = (char *)pFile->lockingContext;
  int rc;

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->eFileLock==eFileLock ){
    return SQLITE_OK;
  }

static int semUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  sem_t *pSem = pFile->pInode->pSem;

  assert( pFile );
  assert( pSem );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->eFileLock==eFileLock ){
    return SQLITE_OK;
  }
  

#else
    newOffset = lseek(id->h, offset, SEEK_SET);
    SimulateIOError( newOffset-- );
    if( newOffset!=offset ){
      if( newOffset == -1 ){
        ((unixFile*)id)->lastErrno = errno;
      }else{
        ((unixFile*)id)->lastErrno = 0;			
      }
      return -1;
    }
    got = osRead(id->h, pBuf, cnt);
#endif
    if( got==cnt ) break;
    if( got<0 ){

  do{
    newOffset = lseek(id->h, offset, SEEK_SET);
    SimulateIOError( newOffset-- );
    if( newOffset!=offset ){
      if( newOffset == -1 ){
        ((unixFile*)id)->lastErrno = errno;
      }else{
        ((unixFile*)id)->lastErrno = 0;			
      }
      return -1;
    }
    got = osWrite(id->h, pBuf, cnt);
  }while( got<0 && errno==EINTR );
#endif
  TIMER_END;

** as POSIX read & write locks over fixed set of locations (via fsctl),
** on AFP and SMB only exclusive byte-range locks are available via fsctl
** with _IOWR('z', 23, struct ByteRangeLockPB2) to track the same 5 states.
** To simulate a F_RDLCK on the shared range, on AFP a randomly selected
** address in the shared range is taken for a SHARED lock, the entire
** shared range is taken for an EXCLUSIVE lock):
**
**      PENDING_BYTE        0x40000000		   	
**      RESERVED_BYTE       0x40000001
**      SHARED_RANGE        0x40000002 -> 0x40000200
**
** This works well on the local file system, but shows a nearly 100x
** slowdown in read performance on AFP because the AFP client disables
** the read cache when byte-range locks are present.  Enabling the read
** cache exposes a cache coherency problem that is present on all OS X

# define FILE_FLAG_MASK          (0xFF3C0000)
#endif

#ifndef FILE_ATTRIBUTE_MASK
# define FILE_ATTRIBUTE_MASK     (0x0003FFF7)
#endif


/* Forward references */
typedef struct winShm winShm;           /* A connection to shared-memory */
typedef struct winShmNode winShmNode;   /* A region of shared-memory */


/*
** WinCE lacks native support for file locking so we have to fake it
** with some code of our own.
*/
#if SQLITE_OS_WINCE
typedef struct winceLock {

  const sqlite3_io_methods *pMethod; /*** Must be first ***/
  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
  HANDLE h;               /* Handle for accessing the file */
  u8 locktype;            /* Type of lock currently held on this file */
  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
  DWORD lastErrno;        /* The Windows errno from the last I/O error */

  winShm *pShm;           /* Instance of shared memory on this file */

  const char *zPath;      /* Full pathname of this file */
  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
#if SQLITE_OS_WINCE
  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
  HANDLE hShared;         /* Shared memory segment used for locking */
  winceLock local;        /* Locks obtained by this instance of winFile */

/*
 * The size of the buffer used by sqlite3_win32_write_debug().
 */
#ifndef SQLITE_WIN32_DBG_BUF_SIZE
#  define SQLITE_WIN32_DBG_BUF_SIZE   ((int)(4096-sizeof(DWORD)))
#endif

















/*
 * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
 * various Win32 API heap functions instead of our own.
 */
#ifdef SQLITE_WIN32_MALLOC

/*

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

#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)

#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)

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

#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[6].pCurrent)

#endif

#ifndef osLockFileEx
#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[45].pCurrent)
#endif

#if !SQLITE_OS_WINRT
  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
#else
  { "MapViewOfFile",           (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        SIZE_T))aSyscall[46].pCurrent)

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

#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[55].pCurrent)


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




#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[56].pCurrent)

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

#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
        LPCSTR,LPBOOL))aSyscall[57].pCurrent)

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

#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[60].pCurrent)

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

#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
        BOOL))aSyscall[61].pCurrent)

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

#define osSetFilePointerEx ((BOOL(WINAPI*)(HANDLE,LARGE_INTEGER, \
        PLARGE_INTEGER,DWORD))aSyscall[62].pCurrent)

#if SQLITE_OS_WINRT
  { "GetFileInformationByHandleEx", (SYSCALL)GetFileInformationByHandleEx, 0 },
#else
  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
#endif

#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[63].pCurrent)

#if SQLITE_OS_WINRT
  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
#else
  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
        SIZE_T))aSyscall[64].pCurrent)

#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[70].pCurrent)

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

#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[71].pCurrent)

#if SQLITE_OS_WINRT
  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
#else
  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
#endif

#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[72].pCurrent)

    return 0;
  }
  zFilenameMbcs = unicodeToMbcs(zTmpWide);
  sqlite3_free(zTmpWide);
  return zFilenameMbcs;
}






































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

** It logs a message using sqlite3_log() containing the current value of
** error code and, if possible, the human-readable equivalent from 
** FormatMessage.
**
** The first argument passed to the macro should be the error code that
** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
** The two subsequent arguments should be the name of the OS function that
** failed and the the associated file-system path, if any.
*/
#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
static int winLogErrorAtLine(
  int errcode,                    /* SQLite error code */
  DWORD lastErrno,                /* Win32 last error */
  const char *zFunc,              /* Name of OS function that failed */
  const char *zPath,              /* File path associated with error */

*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(sqlite3_file *id){
  int rc, cnt = 0;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );

  assert( pFile->pShm==0 );

  OSTRACE(("CLOSE %d\n", pFile->h));
  do{
    rc = osCloseHandle(pFile->h);
    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (sqlite3_win32_sleep(100), 1) );
#if SQLITE_OS_WINCE
#define WINCE_DELETION_ATTEMPTS 3

       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL 
       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_MASTER_JOURNAL 
       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
  );

  assert( id!=0 );
  UNUSED_PARAMETER(pVfs);








  pFile->h = INVALID_HANDLE_VALUE;

  /* If the second argument to this function is NULL, generate a 
  ** temporary file name to use 
  */
  if( !zUtf8Name ){

  }

  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
  pFile->lastErrno = NO_ERROR;
  pFile->pVfs = pVfs;

  pFile->pShm = 0;

  pFile->zPath = zName;
  if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pFile->ctrlFlags |= WINFILE_PSOW;
  }

#if SQLITE_OS_WINCE
  if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB

  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 = sqlite3_malloc( (sz+7)/8 + 1 );
  pTmpSpace = sqlite3_malloc(BITVEC_SZ);
  if( pBitvec==0 || pV==0 || pTmpSpace==0  ) goto bitvec_end;
  memset(pV, 0, (sz+7)/8 + 1);

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

  /* Run the program */
  pc = 0;

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

  pcache1LeaveMutex(p->pGroup);
  if( p->nHash ){ sqlite3BeginBenignMalloc(); }
  apNew = (PgHdr1 **)sqlite3_malloc(sizeof(PgHdr1 *)*nNew);
  if( p->nHash ){ sqlite3EndBenignMalloc(); }
  pcache1EnterMutex(p->pGroup);
  if( apNew ){
    memset(apNew, 0, sizeof(PgHdr1 *)*nNew);
    for(i=0; i<p->nHash; i++){
      PgHdr1 *pPage;
      PgHdr1 *pNext = p->apHash[i];
      while( (pPage = pNext)!=0 ){
        unsigned int h = pPage->iKey % nNew;
        pNext = pPage->pNext;
        pPage->pNext = apNew[h];

  int separateCache = sqlite3GlobalConfig.bCoreMutex>0;
#endif

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

  sz = sizeof(PCache1) + sizeof(PGroup)*separateCache;
  pCache = (PCache1 *)sqlite3_malloc(sz);
  if( pCache ){
    memset(pCache, 0, sz);
    if( separateCache ){
      pGroup = (PGroup*)&pCache[1];
      pGroup->mxPinned = 10;
    }else{
      pGroup = &pcache1.grp;
    }
    pCache->pGroup = pGroup;

    return 1;
  }else{
    return 0;
  }
}

/*
** Check to see if element iRowid was inserted into the the rowset as
** part of any insert batch prior to iBatch.  Return 1 or 0.
**
** If this is the first test of a new batch and if there exist entires
** on pRowSet->pEntry, then sort those entires into the forest at
** pRowSet->pForest so that they can be tested.
*/
SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, u8 iBatch, sqlite3_int64 iRowid){

**     being deleted, truncated, or zeroed.
** 
** (6) If a master journal file is used, then all writes to the database file
**     are synced prior to the master journal being deleted.
** 
** Definition: Two databases (or the same database at two points it time)
** are said to be "logically equivalent" if they give the same answer to
** all queries.  Note in particular the the content of freelist leaf
** pages can be changed arbitarily without effecting the logical equivalence
** of the database.
** 
** (7) At any time, if any subset, including the empty set and the total set,
**     of the unsynced changes to a rollback journal are removed and the 
**     journal is rolled back, the resulting database file will be logical
**     equivalent to the database file at the beginning of the transaction.

/*
** Sync the journal. In other words, make sure all the pages that have
** been written to the journal have actually reached the surface of the
** disk and can be restored in the event of a hot-journal rollback.
**
** If the Pager.noSync flag is set, then this function is a no-op.
** Otherwise, the actions required depend on the journal-mode and the 
** device characteristics of the the file-system, as follows:
**
**   * If the journal file is an in-memory journal file, no action need
**     be taken.
**
**   * Otherwise, if the device does not support the SAFE_APPEND property,
**     then the nRec field of the most recently written journal header
**     is updated to contain the number of journal records that have

** connection to it closes.  Because the wal-index is transient, it can
** use an architecture-specific format; it does not have to be cross-platform.
** Hence, unlike the database and WAL file formats which store all values
** as big endian, the wal-index can store multi-byte values in the native
** byte order of the host computer.
**
** The purpose of the wal-index is to answer this question quickly:  Given
** a page number P, return the index of the last frame for page P in the WAL,

** or return NULL if there are no frames for page P in the WAL.
**
** The wal-index consists of a header region, followed by an one or
** more index blocks.  
**
** The wal-index header contains the total number of frames within the WAL
** in the the mxFrame field.  
**
** Each index block except for the first contains information on 
** HASHTABLE_NPAGE frames. The first index block contains information on
** HASHTABLE_NPAGE_ONE frames. The values of HASHTABLE_NPAGE_ONE and 
** HASHTABLE_NPAGE are selected so that together the wal-index header and
** first index block are the same size as all other index blocks in the
** wal-index.

    ** currently holding locks that exclude all other readers, writers and
    ** checkpointers.
    */
    pInfo = walCkptInfo(pWal);
    pInfo->nBackfill = 0;
    pInfo->aReadMark[0] = 0;
    for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;


    /* If more than one frame was recovered from the log file, report an
    ** event via sqlite3_log(). This is to help with identifying performance
    ** problems caused by applications routinely shutting down without
    ** checkpointing the log file.
    */
    if( pWal->hdr.nPage ){

  mxPage = pWal->hdr.nPage;
  for(i=1; i<WAL_NREADER; i++){
    u32 y = pInfo->aReadMark[i];
    if( mxSafeFrame>y ){
      assert( y<=pWal->hdr.mxFrame );
      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
      if( rc==SQLITE_OK ){
        pInfo->aReadMark[i] = READMARK_NOT_USED;
        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
      }else if( rc==SQLITE_BUSY ){
        mxSafeFrame = y;
        xBusy = 0;
      }else{
        goto walcheckpoint_out;
      }

        pWal->nCkpt++;
        pWal->hdr.mxFrame = 0;
        sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
        aSalt[1] = salt1;
        walIndexWriteHdr(pWal);
        pInfo->nBackfill = 0;

        for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
        assert( pInfo->aReadMark[0]==0 );
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }else if( rc!=SQLITE_BUSY ){
        return rc;
      }
    }
    walUnlockShared(pWal, WAL_READ_LOCK(0));

  u8 wrFlag;                /* True if writable */
  u8 atLast;                /* Cursor pointing to the last entry */
  u8 validNKey;             /* True if info.nKey is valid */
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
#ifndef SQLITE_OMIT_INCRBLOB
  u8 isIncrblobHandle;      /* True if this cursor is an incr. io handle */
#endif

  i16 iPage;                            /* Index of current page in apPage */
  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};

/*
** Potential values for BtCursor.eState.

        /* Start of free block is off the page */
        return SQLITE_CORRUPT_BKPT; 
      }
      next = get2byte(&data[pc]);
      size = get2byte(&data[pc+2]);
      if( (next>0 && next<=pc+size+3) || pc+size>usableSize ){
        /* Free blocks must be in ascending order. And the last byte of
	** the free-block must lie on the database page.  */
        return SQLITE_CORRUPT_BKPT; 
      }
      nFree = nFree + size;
      pc = next;
    }

    /* At this point, nFree contains the sum of the offset to the start

          btreeInvokeBusyHandler(pBt) );

  if( rc==SQLITE_OK ){
    if( p->inTrans==TRANS_NONE ){
      pBt->nTransaction++;
#ifndef SQLITE_OMIT_SHARED_CACHE
      if( p->sharable ){
	assert( p->lock.pBtree==p && p->lock.iTable==1 );
        p->lock.eLock = READ_LOCK;
        p->lock.pNext = pBt->pLock;
        pBt->pLock = &p->lock;
      }
#endif
    }
    p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);

** If aOvflSpace is set to a null pointer, this function returns 
** SQLITE_NOMEM.
*/
static int balance_nonroot(
  MemPage *pParent,               /* Parent page of siblings being balanced */
  int iParentIdx,                 /* Index of "the page" in pParent */
  u8 *aOvflSpace,                 /* page-size bytes of space for parent ovfl */
  int isRoot                      /* True if pParent is a root-page */

){
  BtShared *pBt;               /* The whole database */
  int nCell = 0;               /* Number of cells in apCell[] */
  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
  int nNew = 0;                /* Number of pages in apNew[] */
  int nOld;                    /* Number of pages in apOld[] */
  int i, j, k;                 /* Loop counters */

  ** way, the remainder of the function does not have to deal with any
  ** overflow cells in the parent page, since if any existed they will
  ** have already been removed.
  */
  i = pParent->nOverflow + pParent->nCell;
  if( i<2 ){
    nxDiv = 0;
    nOld = i+1;
  }else{
    nOld = 3;

    if( iParentIdx==0 ){                 
      nxDiv = 0;
    }else if( iParentIdx==i ){
      nxDiv = i-2;
    }else{

      nxDiv = iParentIdx-1;
    }
    i = 2;
  }

  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
    pRight = &pParent->aData[pParent->hdrOffset+8];
  }else{
    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
  }
  pgno = get4byte(pRight);
  while( 1 ){

  szCell = (u16*)&apCell[nMaxCells];
  aSpace1 = (u8*)&szCell[nMaxCells];
  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );

  /*
  ** Load pointers to all cells on sibling pages and the divider cells
  ** into the local apCell[] array.  Make copies of the divider cells
  ** into space obtained from aSpace1[] and remove the the divider Cells
  ** from pParent.
  **
  ** If the siblings are on leaf pages, then the child pointers of the
  ** divider cells are stripped from the cells before they are copied
  ** into aSpace1[].  In this way, all cells in apCell[] are without
  ** child pointers.  If siblings are not leaves, then all cell in
  ** apCell[] include child pointers.  Either way, all cells in apCell[]

    int r;              /* Index of right-most cell in left sibling */
    int d;              /* Index of first cell to the left of right sibling */

    r = cntNew[i-1] - 1;
    d = r + 1 - leafData;
    assert( d<nMaxCells );
    assert( r<nMaxCells );

    while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){

      szRight += szCell[d] + 2;
      szLeft -= szCell[r] + 2;
      cntNew[i-1]--;
      r = cntNew[i-1] - 1;
      d = r + 1 - leafData;
    }
    szNew[i] = szRight;

      pNew = apNew[i] = apOld[i];
      apOld[i] = 0;
      rc = sqlite3PagerWrite(pNew->pDbPage);
      nNew++;
      if( rc ) goto balance_cleanup;
    }else{
      assert( i>0 );
      rc = allocateBtreePage(pBt, &pNew, &pgno, pgno, 0);
      if( rc ) goto balance_cleanup;
      apNew[i] = pNew;
      nNew++;

      /* Set the pointer-map entry for the new sibling page. */
      if( ISAUTOVACUUM ){
        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);

    for(i=0; i<nCell; i++){
      int isDivider = 0;
      while( i==iNextOld ){
        /* Cell i is the cell immediately following the last cell on old
        ** sibling page j. If the siblings are not leaf pages of an
        ** intkey b-tree, then cell i was a divider cell. */
        assert( j+1 < ArraySize(apCopy) );

        pOld = apCopy[++j];
        iNextOld = i + !leafData + pOld->nCell + pOld->nOverflow;
        if( pOld->nOverflow ){
          nOverflow = pOld->nOverflow;
          iOverflow = i + !leafData + pOld->aiOvfl[0];
        }
        isDivider = !leafData;  

          ** different page). Once this subsequent call to balance_nonroot() 
          ** has completed, it is safe to release the pSpace buffer used by
          ** the previous call, as the overflow cell data will have been 
          ** copied either into the body of a database page or into the new
          ** pSpace buffer passed to the latter call to balance_nonroot().
          */
          u8 *pSpace = sqlite3PageMalloc(pCur->pBt->pageSize);
          rc = balance_nonroot(pParent, iIdx, pSpace, iPage==1);
          if( pFree ){
            /* If pFree is not NULL, it points to the pSpace buffer used 
            ** by a previous call to balance_nonroot(). Its contents are
            ** now stored either on real database pages or within the 
            ** new pSpace buffer, so it may be safely freed here. */
            sqlite3PageFree(pFree);
          }

      }
    }
  }

  pBt->btsFlags &= ~BTS_NO_WAL;
  return rc;
}










/************** End of btree.c ***********************************************/
/************** Begin file backup.c ******************************************/
/*
** 2009 January 28
**
** The author disclaims copyright to this source code.  In place of

    );
    p = 0;
  }else {
    /* Allocate space for a new sqlite3_backup object...
    ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
    ** call to sqlite3_backup_init() and is destroyed by a call to
    ** sqlite3_backup_finish(). */
    p = (sqlite3_backup *)sqlite3_malloc(sizeof(sqlite3_backup));
    if( !p ){
      sqlite3Error(pDestDb, SQLITE_NOMEM, 0);
    }
  }

  /* If the allocation succeeded, populate the new object. */
  if( p ){
    memset(p, 0, sizeof(sqlite3_backup));
    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
    p->pDestDb = pDestDb;
    p->pSrcDb = pSrcDb;
    p->iNext = 1;
    p->isAttached = 0;

}

/*
** Release all resources associated with an sqlite3_backup* handle.
*/
SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p){
  sqlite3_backup **pp;                 /* Ptr to head of pagers backup list */
  MUTEX_LOGIC( sqlite3_mutex *mutex; ) /* Mutex to protect source database */
  int rc;                              /* Value to return */

  /* Enter the mutexes */
  if( p==0 ) return SQLITE_OK;

  sqlite3_mutex_enter(p->pSrcDb->mutex);
  sqlite3BtreeEnter(p->pSrc);
  MUTEX_LOGIC( mutex = p->pSrcDb->mutex; )
  if( p->pDestDb ){
    sqlite3_mutex_enter(p->pDestDb->mutex);
  }

  /* Detach this backup from the source pager. */
  if( p->pDestDb ){
    p->pSrc->nBackup--;

  /* Set the error code of the destination database handle. */
  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
  sqlite3Error(p->pDestDb, rc, 0);

  /* Exit the mutexes and free the backup context structure. */
  if( p->pDestDb ){
    sqlite3_mutex_leave(p->pDestDb->mutex);
  }
  sqlite3BtreeLeave(p->pSrc);
  if( p->pDestDb ){
    /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
    ** call to sqlite3_backup_init() and is destroyed by a call to
    ** sqlite3_backup_finish(). */
    sqlite3_free(p);
  }
  sqlite3_mutex_leave(mutex);
  return rc;
}

/*
** Return the number of pages still to be backed up as of the most recent
** call to sqlite3_backup_step().
*/

    pOp->p4.z = sqlite3DbStrNDup(p->db, zP4, n);
    pOp->p4type = P4_DYNAMIC;
  }
}

#ifndef NDEBUG
/*
** Change the comment on the the most recently coded instruction.  Or
** insert a No-op and add the comment to that new instruction.  This
** makes the code easier to read during debugging.  None of this happens
** in a production build.
*/
static void vdbeVComment(Vdbe *p, const char *zFormat, va_list ap){
  assert( p->nOp>0 || p->aOp==0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );

** Delete an entire VDBE.
*/
SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
  sqlite3 *db;

  if( NEVER(p==0) ) return;
  db = p->db;

  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( db->pVdbe==p );
    db->pVdbe = p->pNext;
  }
  if( p->pNext ){

  if( pStmt==0 ){
    /* IMPLEMENTATION-OF: R-57228-12904 Invoking sqlite3_finalize() on a NULL
    ** pointer is a harmless no-op. */
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3 *db = v->db;
#if SQLITE_THREADSAFE
    sqlite3_mutex *mutex;
#endif
    if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
#if SQLITE_THREADSAFE
    mutex = v->db->mutex;
#endif
    sqlite3_mutex_enter(mutex);
    rc = sqlite3VdbeFinalize(v);
    rc = sqlite3ApiExit(db, rc);
    sqlite3_mutex_leave(mutex);
  }
  return rc;
}

/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from

/*
** Allocate a new Explain object
*/
SQLITE_PRIVATE void sqlite3ExplainBegin(Vdbe *pVdbe){
  if( pVdbe ){
    Explain *p;
    sqlite3BeginBenignMalloc();
    p = sqlite3_malloc( sizeof(Explain) );
    if( p ){
      memset(p, 0, sizeof(*p));
      p->pVdbe = pVdbe;
      sqlite3_free(pVdbe->pExplain);
      pVdbe->pExplain = p;
      sqlite3StrAccumInit(&p->str, p->zBase, sizeof(p->zBase),
                          SQLITE_MAX_LENGTH);
      p->str.useMalloc = 2;
    }else{

        }
        nProgressOps = 0;
      }
      nProgressOps++;
    }
#endif

    /* On any opcode with the "out2-prerelase" tag, free any
    ** external allocations out of mem[p2] and set mem[p2] to be
    ** an undefined integer.  Opcodes will either fill in the integer
    ** value or convert mem[p2] to a different type.
    */
    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
      assert( pOp->p2>0 );

  int iDb;
  int wrFlag;
  Btree *pX;
  VdbeCursor *pCur;
  Db *pDb;
#endif /* local variables moved into u.ax */




  if( p->expired ){
    rc = SQLITE_ABORT;
    break;
  }

  u.ax.nField = 0;
  u.ax.pKeyInfo = 0;

    assert( sqlite3SchemaMutexHeld(db, u.ax.iDb, 0) );
    if( u.ax.pDb->pSchema->file_format < p->minWriteFileFormat ){
      p->minWriteFileFormat = u.ax.pDb->pSchema->file_format;
    }
  }else{
    u.ax.wrFlag = 0;
  }
  if( pOp->p5 ){
    assert( u.ax.p2>0 );
    assert( u.ax.p2<=p->nMem );
    pIn2 = &aMem[u.ax.p2];
    assert( memIsValid(pIn2) );
    assert( (pIn2->flags & MEM_Int)!=0 );
    sqlite3VdbeMemIntegerify(pIn2);
    u.ax.p2 = (int)pIn2->u.i;

  assert( pOp->p1>=0 );
  u.ax.pCur = allocateCursor(p, pOp->p1, u.ax.nField, u.ax.iDb, 1);
  if( u.ax.pCur==0 ) goto no_mem;
  u.ax.pCur->nullRow = 1;
  u.ax.pCur->isOrdered = 1;
  rc = sqlite3BtreeCursor(u.ax.pX, u.ax.p2, u.ax.wrFlag, u.ax.pKeyInfo, u.ax.pCur->pCursor);
  u.ax.pCur->pKeyInfo = u.ax.pKeyInfo;



  /* Since it performs no memory allocation or IO, the only value that
  ** sqlite3BtreeCursor() may return is SQLITE_OK. */
  assert( rc==SQLITE_OK );

  /* Set the VdbeCursor.isTable and isIndex variables. Previous versions of
  ** SQLite used to check if the root-page flags were sane at this point

*/


#ifndef SQLITE_OMIT_MERGE_SORT

typedef struct VdbeSorterIter VdbeSorterIter;
typedef struct SorterRecord SorterRecord;


/*
** NOTES ON DATA STRUCTURE USED FOR N-WAY MERGES:
**
** As keys are added to the sorter, they are written to disk in a series
** of sorted packed-memory-arrays (PMAs). The size of each PMA is roughly
** the same as the cache-size allowed for temporary databases. In order

  i64 iReadOff;                   /* Current read offset */
  i64 iEof;                       /* 1 byte past EOF for this iterator */
  int nAlloc;                     /* Bytes of space at aAlloc */
  int nKey;                       /* Number of bytes in key */
  sqlite3_file *pFile;            /* File iterator is reading from */
  u8 *aAlloc;                     /* Allocated space */
  u8 *aKey;                       /* Pointer to current key */


















};

/*
** A structure to store a single record. All in-memory records are connected
** together into a linked list headed at VdbeSorter.pRecord using the 
** SorterRecord.pNext pointer.
*/

/*
** Free all memory belonging to the VdbeSorterIter object passed as the second
** argument. All structure fields are set to zero before returning.
*/
static void vdbeSorterIterZero(sqlite3 *db, VdbeSorterIter *pIter){
  sqlite3DbFree(db, pIter->aAlloc);

  memset(pIter, 0, sizeof(VdbeSorterIter));
}


















































































































/*
** Advance iterator pIter to the next key in its PMA. Return SQLITE_OK if
** no error occurs, or an SQLite error code if one does.
*/
static int vdbeSorterIterNext(
  sqlite3 *db,                    /* Database handle (for sqlite3DbMalloc() ) */
  VdbeSorterIter *pIter           /* Iterator to advance */
){
  int rc;                         /* Return Code */
  int nRead;                      /* Number of bytes read */
  int nRec = 0;                   /* Size of record in bytes */
  int iOff = 0;                   /* Size of serialized size varint in bytes */

  assert( pIter->iEof>=pIter->iReadOff );
  if( pIter->iEof-pIter->iReadOff>5 ){
    nRead = 5;
  }else{
    nRead = (int)(pIter->iEof - pIter->iReadOff);
  }
  if( nRead<=0 ){
    /* This is an EOF condition */
    vdbeSorterIterZero(db, pIter);
    return SQLITE_OK;
  }

  rc = sqlite3OsRead(pIter->pFile, pIter->aAlloc, nRead, pIter->iReadOff);
  if( rc==SQLITE_OK ){
    iOff = getVarint32(pIter->aAlloc, nRec);
    if( (iOff+nRec)>nRead ){
      int nRead2;                   /* Number of extra bytes to read */
      if( (iOff+nRec)>pIter->nAlloc ){
        int nNew = pIter->nAlloc*2;
        while( (iOff+nRec)>nNew ) nNew = nNew*2;
        pIter->aAlloc = sqlite3DbReallocOrFree(db, pIter->aAlloc, nNew);
        if( !pIter->aAlloc ) return SQLITE_NOMEM;
        pIter->nAlloc = nNew;
      }
  
      nRead2 = iOff + nRec - nRead;
      rc = sqlite3OsRead(
          pIter->pFile, &pIter->aAlloc[nRead], nRead2, pIter->iReadOff+nRead
      );
    }
  }

  assert( rc!=SQLITE_OK || nRec>0 );
  pIter->iReadOff += iOff+nRec;
  pIter->nKey = nRec;
  pIter->aKey = &pIter->aAlloc[iOff];
  return rc;
}

/*
** Write a single varint, value iVal, to file-descriptor pFile. Return
** SQLITE_OK if successful, or an SQLite error code if some error occurs.
**
** The value of *piOffset when this function is called is used as the byte
** offset in file pFile to write to. Before returning, *piOffset is 
** incremented by the number of bytes written.
*/
static int vdbeSorterWriteVarint(
  sqlite3_file *pFile,            /* File to write to */
  i64 iVal,                       /* Value to write as a varint */
  i64 *piOffset                   /* IN/OUT: Write offset in file pFile */
){
  u8 aVarint[9];                  /* Buffer large enough for a varint */
  int nVarint;                    /* Number of used bytes in varint */
  int rc;                         /* Result of write() call */

  nVarint = sqlite3PutVarint(aVarint, iVal);
  rc = sqlite3OsWrite(pFile, aVarint, nVarint, *piOffset);
  *piOffset += nVarint;

  return rc;
}

/*
** Read a single varint from file-descriptor pFile. Return SQLITE_OK if
** successful, or an SQLite error code if some error occurs.
**
** The value of *piOffset when this function is called is used as the
** byte offset in file pFile from whence to read the varint. If successful
** (i.e. if no IO error occurs), then *piOffset is set to the offset of
** the first byte past the end of the varint before returning. *piVal is
** set to the integer value read. If an error occurs, the final values of
** both *piOffset and *piVal are undefined.
*/
static int vdbeSorterReadVarint(
  sqlite3_file *pFile,            /* File to read from */
  i64 *piOffset,                  /* IN/OUT: Read offset in pFile */
  i64 *piVal                      /* OUT: Value read from file */
){
  u8 aVarint[9];                  /* Buffer large enough for a varint */
  i64 iOff = *piOffset;           /* Offset in file to read from */
  int rc;                         /* Return code */

  rc = sqlite3OsRead(pFile, aVarint, 9, iOff);
  if( rc==SQLITE_OK ){
    *piOffset += getVarint(aVarint, (u64 *)piVal);
  }

  return rc;
}

/*
** Initialize iterator pIter to scan through the PMA stored in file pFile
** starting at offset iStart and ending at offset iEof-1. This function 
** leaves the iterator pointing to the first key in the PMA (or EOF if the 
** PMA is empty).
*/
static int vdbeSorterIterInit(
  sqlite3 *db,                    /* Database handle */
  VdbeSorter *pSorter,            /* Sorter object */
  i64 iStart,                     /* Start offset in pFile */
  VdbeSorterIter *pIter,          /* Iterator to populate */
  i64 *pnByte                     /* IN/OUT: Increment this value by PMA size */
){
  int rc;




  assert( pSorter->iWriteOff>iStart );
  assert( pIter->aAlloc==0 );

  pIter->pFile = pSorter->pTemp1;
  pIter->iReadOff = iStart;
  pIter->nAlloc = 128;
  pIter->aAlloc = (u8 *)sqlite3DbMallocRaw(db, pIter->nAlloc);



  if( !pIter->aAlloc ){
    rc = SQLITE_NOMEM;
  }else{

    i64 nByte;                         /* Total size of PMA in bytes */







    rc = vdbeSorterReadVarint(pSorter->pTemp1, &pIter->iReadOff, &nByte);



    *pnByte += nByte;




    pIter->iEof = pIter->iReadOff + nByte;

  }


  if( rc==SQLITE_OK ){
    rc = vdbeSorterIterNext(db, pIter);
  }
  return rc;
}

** is true and key1 contains even a single NULL value, it is considered to
** be less than key2. Even if key2 also contains NULL values.
**
** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace
** has been allocated and contains an unpacked record that is used as key2.
*/
static void vdbeSorterCompare(
  VdbeCursor *pCsr,               /* Cursor object (for pKeyInfo) */
  int bOmitRowid,                 /* Ignore rowid field at end of keys */
  void *pKey1, int nKey1,         /* Left side of comparison */
  void *pKey2, int nKey2,         /* Right side of comparison */
  int *pRes                       /* OUT: Result of comparison */
){
  KeyInfo *pKeyInfo = pCsr->pKeyInfo;
  VdbeSorter *pSorter = pCsr->pSorter;
  UnpackedRecord *r2 = pSorter->pUnpacked;
  int i;

}

/*
** This function is called to compare two iterator keys when merging 
** multiple b-tree segments. Parameter iOut is the index of the aTree[] 
** value to recalculate.
*/
static int vdbeSorterDoCompare(VdbeCursor *pCsr, int iOut){
  VdbeSorter *pSorter = pCsr->pSorter;
  int i1;
  int i2;
  int iRes;
  VdbeSorterIter *p1;
  VdbeSorterIter *p2;

}

/*
** Merge the two sorted lists p1 and p2 into a single list.
** Set *ppOut to the head of the new list.
*/
static void vdbeSorterMerge(
  VdbeCursor *pCsr,               /* For pKeyInfo */
  SorterRecord *p1,               /* First list to merge */
  SorterRecord *p2,               /* Second list to merge */
  SorterRecord **ppOut            /* OUT: Head of merged list */
){
  SorterRecord *pFinal = 0;
  SorterRecord **pp = &pFinal;
  void *pVal2 = p2 ? p2->pVal : 0;

}

/*
** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
** occurs.
*/
static int vdbeSorterSort(VdbeCursor *pCsr){
  int i;
  SorterRecord **aSlot;
  SorterRecord *p;
  VdbeSorter *pSorter = pCsr->pSorter;

  aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *));
  if( !aSlot ){

  }
  pSorter->pRecord = p;

  sqlite3_free(aSlot);
  return SQLITE_OK;
}























































































/*
** Write the current contents of the in-memory linked-list to a PMA. Return
** SQLITE_OK if successful, or an SQLite error code otherwise.
**
** The format of a PMA is:
**
**     * A varint. This varint contains the total number of bytes of content
**       in the PMA (not including the varint itself).
**
**     * One or more records packed end-to-end in order of ascending keys. 
**       Each record consists of a varint followed by a blob of data (the 
**       key). The varint is the number of bytes in the blob of data.
*/
static int vdbeSorterListToPMA(sqlite3 *db, VdbeCursor *pCsr){
  int rc = SQLITE_OK;             /* Return code */
  VdbeSorter *pSorter = pCsr->pSorter;




  if( pSorter->nInMemory==0 ){
    assert( pSorter->pRecord==0 );
    return rc;
  }

  rc = vdbeSorterSort(pCsr);

  /* If the first temporary PMA file has not been opened, open it now. */
  if( rc==SQLITE_OK && pSorter->pTemp1==0 ){
    rc = vdbeSorterOpenTempFile(db, &pSorter->pTemp1);
    assert( rc!=SQLITE_OK || pSorter->pTemp1 );
    assert( pSorter->iWriteOff==0 );
    assert( pSorter->nPMA==0 );
  }

  if( rc==SQLITE_OK ){
    i64 iOff = pSorter->iWriteOff;
    SorterRecord *p;
    SorterRecord *pNext = 0;
    static const char eightZeros[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };


    pSorter->nPMA++;
    rc = vdbeSorterWriteVarint(pSorter->pTemp1, pSorter->nInMemory, &iOff);
    for(p=pSorter->pRecord; rc==SQLITE_OK && p; p=pNext){
      pNext = p->pNext;
      rc = vdbeSorterWriteVarint(pSorter->pTemp1, p->nVal, &iOff);

      if( rc==SQLITE_OK ){
        rc = sqlite3OsWrite(pSorter->pTemp1, p->pVal, p->nVal, iOff);
        iOff += p->nVal;
      }

      sqlite3DbFree(db, p);
    }

    /* This assert verifies that unless an error has occurred, the size of 
    ** the PMA on disk is the same as the expected size stored in
    ** pSorter->nInMemory. */ 
    assert( rc!=SQLITE_OK || pSorter->nInMemory==(
          iOff-pSorter->iWriteOff-sqlite3VarintLen(pSorter->nInMemory)
    ));

    pSorter->iWriteOff = iOff;
    if( rc==SQLITE_OK ){
      /* Terminate each file with 8 extra bytes so that from any offset
      ** in the file we can always read 9 bytes without a SHORT_READ error */
      rc = sqlite3OsWrite(pSorter->pTemp1, eightZeros, 8, iOff);
    }
    pSorter->pRecord = p;

  }

  return rc;
}

/*
** Add a record to the sorter.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
  sqlite3 *db,                    /* Database handle */
  VdbeCursor *pCsr,               /* Sorter cursor */
  Mem *pVal                       /* Memory cell containing record */
){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc = SQLITE_OK;             /* Return Code */
  SorterRecord *pNew;             /* New list element */

  assert( pSorter );

  **   * The total memory allocated for the in-memory list is greater 
  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
  */
  if( rc==SQLITE_OK && pSorter->mxPmaSize>0 && (
        (pSorter->nInMemory>pSorter->mxPmaSize)
     || (pSorter->nInMemory>pSorter->mnPmaSize && sqlite3HeapNearlyFull())
  )){





    rc = vdbeSorterListToPMA(db, pCsr);
    pSorter->nInMemory = 0;

  }

  return rc;
}

/*
** Helper function for sqlite3VdbeSorterRewind(). 
*/
static int vdbeSorterInitMerge(
  sqlite3 *db,                    /* Database handle */
  VdbeCursor *pCsr,               /* Cursor handle for this sorter */
  i64 *pnByte                     /* Sum of bytes in all opened PMAs */
){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc = SQLITE_OK;             /* Return code */
  int i;                          /* Used to iterator through aIter[] */
  i64 nByte = 0;                  /* Total bytes in all opened PMAs */

  return rc;
}

/*
** Once the sorter has been populated, this function is called to prepare
** for iterating through its contents in sorted order.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *db, VdbeCursor *pCsr, int *pbEof){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc;                         /* Return code */
  sqlite3_file *pTemp2 = 0;       /* Second temp file to use */
  i64 iWrite2 = 0;                /* Write offset for pTemp2 */
  int nIter;                      /* Number of iterators used */
  int nByte;                      /* Bytes of space required for aIter/aTree */
  int N = 2;                      /* Power of 2 >= nIter */

  assert( pSorter );

  /* If no data has been written to disk, then do not do so now. Instead,
  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
  ** from the in-memory list.  */
  if( pSorter->nPMA==0 ){
    *pbEof = !pSorter->pRecord;
    assert( pSorter->aTree==0 );
    return vdbeSorterSort(pCsr);
  }

  /* Write the current b-tree to a PMA. Close the b-tree cursor. */
  rc = vdbeSorterListToPMA(db, pCsr);
  if( rc!=SQLITE_OK ) return rc;

  /* Allocate space for aIter[] and aTree[]. */
  nIter = pSorter->nPMA;
  if( nIter>SORTER_MAX_MERGE_COUNT ) nIter = SORTER_MAX_MERGE_COUNT;
  assert( nIter>0 );

  do {
    int iNew;                     /* Index of new, merged, PMA */

    for(iNew=0; 
        rc==SQLITE_OK && iNew*SORTER_MAX_MERGE_COUNT<pSorter->nPMA; 
        iNew++
    ){


      i64 nWrite;                 /* Number of bytes in new PMA */



      /* If there are SORTER_MAX_MERGE_COUNT or less PMAs in file pTemp1,
      ** initialize an iterator for each of them and break out of the loop.
      ** These iterators will be incrementally merged as the VDBE layer calls
      ** sqlite3VdbeSorterNext().
      **
      ** Otherwise, if pTemp1 contains more than SORTER_MAX_MERGE_COUNT PMAs,

      /* Open the second temp file, if it is not already open. */
      if( pTemp2==0 ){
        assert( iWrite2==0 );
        rc = vdbeSorterOpenTempFile(db, &pTemp2);
      }

      if( rc==SQLITE_OK ){
        rc = vdbeSorterWriteVarint(pTemp2, nWrite, &iWrite2);
      }

      if( rc==SQLITE_OK ){
        int bEof = 0;


        while( rc==SQLITE_OK && bEof==0 ){
          int nToWrite;
          VdbeSorterIter *pIter = &pSorter->aIter[ pSorter->aTree[1] ];
          assert( pIter->pFile );
          nToWrite = pIter->nKey + sqlite3VarintLen(pIter->nKey);
          rc = sqlite3OsWrite(pTemp2, pIter->aAlloc, nToWrite, iWrite2);
          iWrite2 += nToWrite;
          if( rc==SQLITE_OK ){
            rc = sqlite3VdbeSorterNext(db, pCsr, &bEof);
          }
        }


      }
    }

    if( pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){
      break;
    }else{
      sqlite3_file *pTmp = pSorter->pTemp1;

  *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
  return rc;
}

/*
** Advance to the next element in the sorter.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *db, VdbeCursor *pCsr, int *pbEof){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc;                         /* Return code */

  if( pSorter->aTree ){
    int iPrev = pSorter->aTree[1];/* Index of iterator to advance */
    int i;                        /* Index of aTree[] to recalculate */

}

/*
** Return a pointer to a buffer owned by the sorter that contains the 
** current key.
*/
static void *vdbeSorterRowkey(
  VdbeSorter *pSorter,            /* Sorter object */
  int *pnKey                      /* OUT: Size of current key in bytes */
){
  void *pKey;
  if( pSorter->aTree ){
    VdbeSorterIter *pIter;
    pIter = &pSorter->aIter[ pSorter->aTree[1] ];
    *pnKey = pIter->nKey;
    pKey = pIter->aKey;
  }else{
    *pnKey = pSorter->pRecord->nVal;
    pKey = pSorter->pRecord->pVal;
  }
  return pKey;
}

/*
** Copy the current sorter key into the memory cell pOut.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(VdbeCursor *pCsr, Mem *pOut){
  VdbeSorter *pSorter = pCsr->pSorter;
  void *pKey; int nKey;           /* Sorter key to copy into pOut */

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  if( sqlite3VdbeMemGrow(pOut, nKey, 0) ){
    return SQLITE_NOMEM;
  }

**
** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM).
** Otherwise, set *pRes to a negative, zero or positive value if the
** key in pVal is smaller than, equal to or larger than the current sorter
** key.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterCompare(
  VdbeCursor *pCsr,               /* Sorter cursor */
  Mem *pVal,                      /* Value to compare to current sorter key */
  int *pRes                       /* OUT: Result of comparison */
){
  VdbeSorter *pSorter = pCsr->pSorter;
  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  pKey = vdbeSorterRowkey(pSorter, &nKey);

** If the Walker does not have an xSelectCallback() then this routine
** is a no-op returning WRC_Continue.
*/
SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
  int rc;
  if( p==0 || pWalker->xSelectCallback==0 ) return WRC_Continue;
  rc = WRC_Continue;

  while( p  ){
    rc = pWalker->xSelectCallback(pWalker, p);
    if( rc ) break;
    if( sqlite3WalkSelectExpr(pWalker, p) ) return WRC_Abort;
    if( sqlite3WalkSelectFrom(pWalker, p) ) return WRC_Abort;




    p = p->pPrior;
  }

  return rc & WRC_Abort;
}

/************** End of walker.c **********************************************/
/************** Begin file resolve.c *****************************************/
/*
** 2008 August 18

**
** This file contains routines used for walking the parser tree and
** resolve all identifiers by associating them with a particular
** table and column.
*/
/* #include <stdlib.h> */
/* #include <string.h> */
























/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy.  But for any other kind of expression, this

** Is equivalent to:
**
**     SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set.  We might fix this someday.  Or
** then again, we might not...






*/
static void resolveAlias(
  Parse *pParse,         /* Parsing context */
  ExprList *pEList,      /* A result set */
  int iCol,              /* A column in the result set.  0..pEList->nExpr-1 */
  Expr *pExpr,           /* Transform this into an alias to the result set */
  const char *zType      /* "GROUP" or "ORDER" or "" */

){
  Expr *pOrig;           /* The iCol-th column of the result set */
  Expr *pDup;            /* Copy of pOrig */
  sqlite3 *db;           /* The database connection */

  assert( iCol>=0 && iCol<pEList->nExpr );
  pOrig = pEList->a[iCol].pExpr;
  assert( pOrig!=0 );
  assert( pOrig->flags & EP_Resolved );
  db = pParse->db;
  if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
    pDup = sqlite3ExprDup(db, pOrig, 0);

    pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
    if( pDup==0 ) return;
    if( pEList->a[iCol].iAlias==0 ){
      pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
    }
    pDup->iTable = pEList->a[iCol].iAlias;
  }else if( ExprHasProperty(pOrig, EP_IntValue) || pOrig->u.zToken==0 ){

  Parse *pParse,       /* The parsing context */
  const char *zDb,     /* Name of the database containing table, or NULL */
  const char *zTab,    /* Name of table containing column, or NULL */
  const char *zCol,    /* Name of the column. */
  NameContext *pNC,    /* The name context used to resolve the name */
  Expr *pExpr          /* Make this EXPR node point to the selected column */
){
  int i, j;            /* Loop counters */
  int cnt = 0;                      /* Number of matching column names */
  int cntTab = 0;                   /* Number of matching table names */

  sqlite3 *db = pParse->db;         /* The database connection */
  struct SrcList_item *pItem;       /* Use for looping over pSrcList items */
  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */
  Schema *pSchema = 0;              /* Schema of the expression */
  int isTrigger = 0;

          assert( pExpr->x.pList==0 );
          assert( pExpr->x.pSelect==0 );
          pOrig = pEList->a[j].pExpr;
          if( (pNC->ncFlags&NC_AllowAgg)==0 && ExprHasProperty(pOrig, EP_Agg) ){
            sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
            return WRC_Abort;
          }
          resolveAlias(pParse, pEList, j, pExpr, "");
          cnt = 1;
          pMatch = 0;
          assert( zTab==0 && zDb==0 );
          goto lookupname_end;
        }
      } 
    }

    /* Advance to the next name context.  The loop will exit when either
    ** we have a match (cnt>0) or when we run out of name contexts.
    */
    if( cnt==0 ){
      pNC = pNC->pNext;

    }
  }

  /*
  ** If X and Y are NULL (in other words if only the column name Z is
  ** supplied) and the value of Z is enclosed in double-quotes, then
  ** Z is a string literal if it doesn't match any column names.  In that

        sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
        pNC->nErr++;
      }else if( wrong_num_args ){
        sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
             nId, zId);
        pNC->nErr++;
      }


      if( is_agg ){

        pExpr->op = TK_AGG_FUNCTION;



        pNC->ncFlags |= NC_HasAgg;
      }
      if( is_agg ) pNC->ncFlags &= ~NC_AllowAgg;
      sqlite3WalkExprList(pWalker, pList);
      if( is_agg ) pNC->ncFlags |= NC_AllowAgg;

      /* FIX ME:  Compute pExpr->affinity based on the expected return
      ** type of the function 
      */
      return WRC_Prune;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT:

  assert( pEList!=0 );  /* sqlite3SelectNew() guarantees this */
  for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
    if( pItem->iOrderByCol ){
      if( pItem->iOrderByCol>pEList->nExpr ){
        resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr);
        return 1;
      }
      resolveAlias(pParse, pEList, pItem->iOrderByCol-1, pItem->pExpr, zType);
    }
  }
  return 0;
}

/*
** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.

        ** table allocated and opened above.
        */
        SelectDest dest;
        ExprList *pEList;

        assert( !isRowid );
        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
        dest.affinity = (u8)affinity;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        pExpr->x.pSelect->iLimit = 0;
        if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
          return 0;
        }
        pEList = pExpr->x.pSelect->pEList;
        if( ALWAYS(pEList!=0 && pEList->nExpr>0) ){ 

      assert( pExpr->op==TK_EXISTS || pExpr->op==TK_SELECT );

      assert( ExprHasProperty(pExpr, EP_xIsSelect) );
      pSel = pExpr->x.pSelect;
      sqlite3SelectDestInit(&dest, 0, ++pParse->nMem);
      if( pExpr->op==TK_SELECT ){
        dest.eDest = SRT_Mem;
        sqlite3VdbeAddOp2(v, OP_Null, 0, dest.iParm);
        VdbeComment((v, "Init subquery result"));
      }else{
        dest.eDest = SRT_Exists;
        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
        VdbeComment((v, "Init EXISTS result"));
      }
      sqlite3ExprDelete(pParse->db, pSel->pLimit);
      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0,
                                  &sqlite3IntTokens[1]);
      pSel->iLimit = 0;
      if( sqlite3Select(pParse, pSel, &dest) ){
        return 0;
      }
      rReg = dest.iParm;
      ExprSetIrreducible(pExpr);
      break;
    }
  }

  if( testAddr>=0 ){
    sqlite3VdbeJumpHere(v, testAddr);

    case TK_FUNCTION: {
      ExprList *pFarg;       /* List of function arguments */
      if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;
      }else{
        pFarg = pExpr->x.pList;
      }

      sqlite3ExplainPrintf(pOut, "%sFUNCTION:%s(",
                           op==TK_AGG_FUNCTION ? "AGG_" : "",


                           pExpr->u.zToken);

      if( pFarg ){
        sqlite3ExplainExprList(pOut, pFarg);
      }
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY

    if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
    if( sqlite3ExprCompare(pExprA, pExprB) ) return 1;
  }
  return 0;
}

/*



** This is the expression callback for sqlite3FunctionUsesOtherSrc().
**





** Determine if an expression references any table other than one of the
** tables in pWalker->u.pSrcList and abort if it does.


*/
static int exprUsesOtherSrc(Walker *pWalker, Expr *pExpr){





  if( pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN ){
    int i;

    SrcList *pSrc = pWalker->u.pSrcList;
    for(i=0; i<pSrc->nSrc; i++){
      if( pExpr->iTable==pSrc->a[i].iCursor ) return WRC_Continue;
    }
    return WRC_Abort;


  }else{
    return WRC_Continue;

  }


}

/*
** Determine if any of the arguments to the pExpr Function references
** any SrcList other than pSrcList.  Return true if they do.  Return
** false if pExpr has no argument or has only constant arguments or
** only references tables named in pSrcList.
*/
static int sqlite3FunctionUsesOtherSrc(Expr *pExpr, SrcList *pSrcList){
  Walker w;

  assert( pExpr->op==TK_AGG_FUNCTION );
  memset(&w, 0, sizeof(w));
  w.xExprCallback = exprUsesOtherSrc;

  w.u.pSrcList = pSrcList;


  if( sqlite3WalkExprList(&w, pExpr->x.pList)!=WRC_Continue ) return 1;
  return 0;
}

/*
** Add a new element to the pAggInfo->aCol[] array.  Return the index of
** the new element.  Return a negative number if malloc fails.
*/
static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){

          } /* endif pExpr->iTable==pItem->iCursor */
        } /* end loop over pSrcList */
      }
      return WRC_Prune;
    }
    case TK_AGG_FUNCTION: {
      if( (pNC->ncFlags & NC_InAggFunc)==0
       && !sqlite3FunctionUsesOtherSrc(pExpr, pSrcList)
      ){
        /* Check to see if pExpr is a duplicate of another aggregate 
        ** function that is already in the pAggInfo structure
        */
        struct AggInfo_func *pItem = pAggInfo->aFunc;
        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
          if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){

      ** side-effect of the CREATE TABLE statement is to leave the rootpage 
      ** of the new table in register pParse->regRoot. This is important 
      ** because the OpenWrite opcode below will be needing it. */
      sqlite3NestedParse(pParse,
          "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols
      );
      aRoot[i] = pParse->regRoot;
      aCreateTbl[i] = 1;
    }else{
      /* The table already exists. If zWhere is not NULL, delete all entries 
      ** associated with the table zWhere. If zWhere is NULL, delete the
      ** entire contents of the table. */
      aRoot[i] = pStat->tnum;
      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
      if( zWhere ){

  int mxSample;
  int n;

  UNUSED_PARAMETER(argc);
  nRow = (tRowcnt)sqlite3_value_int64(argv[0]);
  mxSample = sqlite3_value_int(argv[1]);
  n = sizeof(*p) + sizeof(p->a[0])*mxSample;
  p = sqlite3_malloc( n );
  if( p==0 ){
    sqlite3_result_error_nomem(context);
    return;
  }
  memset(p, 0, n);
  p->a = (struct Stat3Sample*)&p[1];
  p->nRow = nRow;
  p->mxSample = mxSample;
  p->nPSample = p->nRow/(mxSample/3+1) + 1;
  sqlite3_randomness(sizeof(p->iPrn), &p->iPrn);
  sqlite3_result_blob(context, p, sizeof(p), sqlite3_free);
}

  /* Delete all indices associated with this table. */
  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
    pNext = pIndex->pNext;
    assert( pIndex->pSchema==pTable->pSchema );
    if( !db || db->pnBytesFreed==0 ){
      char *zName = pIndex->zName; 
      TESTONLY ( Index *pOld = ) sqlite3HashInsert(
	  &pIndex->pSchema->idxHash, zName, sqlite3Strlen30(zName), 0
      );
      assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
      assert( pOld==pIndex || pOld==0 );
    }
    freeIndex(db, pIndex);
  }

    */
    if( pSelect ){
      SelectDest dest;
      Table *pSelTab;

      assert(pParse->nTab==1);
      sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
      sqlite3VdbeChangeP5(v, 1);
      pParse->nTab = 2;
      sqlite3SelectDestInit(&dest, SRT_Table, 1);
      sqlite3Select(pParse, pSelect, &dest);
      sqlite3VdbeAddOp1(v, OP_Close, 1);
      if( pParse->nErr==0 ){
        pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect);
        if( pSelTab==0 ) return;

  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
  }
  pKey = sqlite3IndexKeyinfo(pParse, pIndex);
  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, tnum, iDb, 
                    (char *)pKey, P4_KEYINFO_HANDOFF);
  if( memRootPage>=0 ){
    sqlite3VdbeChangeP5(v, 1);
  }

#ifndef SQLITE_OMIT_MERGE_SORT
  /* Open the sorter cursor if we are to use one. */
  iSorter = pParse->nTab++;
  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, 0, (char*)pKey, P4_KEYINFO);
#else
  iSorter = iTab;

    */
    assert( pName1 && pName2 );
    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
    if( iDb<0 ) goto exit_create_index;
    assert( pName && pName->z );

#ifndef SQLITE_OMIT_TEMPDB
    /* If the index name was unqualified, check if the the table
    ** is a temp table. If so, set the database to 1. Do not do this
    ** if initialising a database schema.
    */
    if( !db->init.busy ){
      pTab = sqlite3SrcListLookup(pParse, pTblName);
      if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
        iDb = 1;

    int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
    int regRowid;                   /* Actual register containing rowids */

    /* Collect rowids of every row to be deleted.
    */
    sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    pWInfo = sqlite3WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, iRowid, 0);
    sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }

** "NULL".  Otherwise, the argument is enclosed in single quotes with
** single-quote escapes.
*/
static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  assert( argc==1 );
  UNUSED_PARAMETER(argc);
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE_INTEGER:











    case SQLITE_FLOAT: {
      sqlite3_result_value(context, argv[0]);
      break;
    }
    case SQLITE_BLOB: {
      char *zText = 0;
      char const *zBlob = sqlite3_value_blob(argv[0]);
      int nBlob = sqlite3_value_bytes(argv[0]);

  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. If the constraint is not deferred, throw an exception for
  ** each row found. Otherwise, for deferred constraints, increment the
  ** deferred constraint counter by nIncr for each row selected.  */
  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite3ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite3WhereEnd(pWInfo);
  }

    int rc, j1;

    regEof = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);      /* EOF <- 0 */
    VdbeComment((v, "SELECT eof flag"));
    sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
    addrSelect = sqlite3VdbeCurrentAddr(v)+2;
    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
    j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    VdbeComment((v, "Jump over SELECT coroutine"));

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, &dest);
    assert( pParse->nErr==0 || rc );
    if( rc || NEVER(pParse->nErr) || db->mallocFailed ){
      goto insert_cleanup;
    }
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
    sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
    VdbeComment((v, "End of SELECT coroutine"));
    sqlite3VdbeJumpHere(v, j1);                          /* label B: */

    regFromSelect = dest.iMem;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
    assert( dest.nMem==nColumn );

    /* Set useTempTable to TRUE if the result of the SELECT statement
    ** should be written into a temporary table (template 4).  Set to
    ** FALSE if each* row of the SELECT can be written directly into
    ** the destination table (template 3).
    **
    ** A temp table must be used if the table being updated is also one

      int addrTop;         /* Label "L" */
      int addrIf;          /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regTempRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
      addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);

    **
    **      C: yield X
    **         if EOF goto D
    **         insert the select result into <table> from R..R+n
    **         goto C
    **      D: ...
    */
    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
    addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRowid = regIns = pParse->nMem+1;

        sqlite3HaltConstraint(
          pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
        break;
      }
      case OE_Replace: {
        /* If there are DELETE triggers on this table and the
        ** recursive-triggers flag is set, call GenerateRowDelete() to
        ** remove the conflicting row from the the table. This will fire
        ** the triggers and remove both the table and index b-tree entries.
        **
        ** Otherwise, if there are no triggers or the recursive-triggers
        ** flag is not set, but the table has one or more indexes, call 
        ** GenerateRowIndexDelete(). This removes the index b-tree entries 
        ** only. The table b-tree entry will be replaced by the new entry 
        ** when it is inserted.  

      { OP_AddImm,      1, 0,        0},    /* 0 */
      { OP_IfNeg,       1, 0,        0},    /* 1 */
      { OP_String8,     0, 3,        0},    /* 2 */
      { OP_ResultRow,   3, 1,        0},
    };

    int isQuick = (sqlite3Tolower(zLeft[0])=='q');














    /* Initialize the VDBE program */
    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
    pParse->nMem = 6;
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "integrity_check", SQLITE_STATIC);

    /* Do an integrity check on each database file */
    for(i=0; i<db->nDb; i++){
      HashElem *x;
      Hash *pTbls;
      int cnt = 0;

      if( OMIT_TEMPDB && i==1 ) continue;


      sqlite3CodeVerifySchema(pParse, i);
      addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1); /* Halt if out of errors */
      sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
      sqlite3VdbeJumpHere(v, addr);

      /* Do an integrity check of the B-Tree
      **
      ** Begin by filling registers 2, 3, ... with the root pages numbers
      ** for all tables and indices in the database.
      */
      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
      pTbls = &db->aDb[i].pSchema->tblHash;
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx;
        sqlite3VdbeAddOp2(v, OP_Integer, pTab->tnum, 2+cnt);
        cnt++;
        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){

}

/*
** Initialize a SelectDest structure.
*/
SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
  pDest->eDest = (u8)eDest;
  pDest->iParm = iParm;
  pDest->affinity = 0;
  pDest->iMem = 0;
  pDest->nMem = 0;
}


/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

  int iBreak              /* Jump here to break out of the inner loop */
){
  Vdbe *v = pParse->pVdbe;
  int i;
  int hasDistinct;        /* True if the DISTINCT keyword is present */
  int regResult;              /* Start of memory holding result set */
  int eDest = pDest->eDest;   /* How to dispose of results */
  int iParm = pDest->iParm;   /* First argument to disposal method */
  int nResultCol;             /* Number of result columns */

  assert( v );
  if( NEVER(v==0) ) return;
  assert( pEList!=0 );
  hasDistinct = distinct>=0;
  if( pOrderBy==0 && !hasDistinct ){
    codeOffset(v, p, iContinue);
  }

  /* Pull the requested columns.
  */
  if( nColumn>0 ){
    nResultCol = nColumn;
  }else{
    nResultCol = pEList->nExpr;
  }
  if( pDest->iMem==0 ){
    pDest->iMem = pParse->nMem+1;
    pDest->nMem = nResultCol;
    pParse->nMem += nResultCol;
  }else{ 
    assert( pDest->nMem==nResultCol );
  }
  regResult = pDest->iMem;
  if( nColumn>0 ){
    for(i=0; i<nColumn; i++){
      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
    }
  }else if( eDest!=SRT_Exists ){
    /* If the destination is an EXISTS(...) expression, the actual
    ** values returned by the SELECT are not required.

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      assert( nColumn==1 );
      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
      if( pOrderBy ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        pushOntoSorter(pParse, pOrderBy, p, regResult);
      }else{

      testcase( eDest==SRT_Output );
      if( pOrderBy ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
        pushOntoSorter(pParse, pOrderBy, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
      }
      break;
    }

  int addrContinue = sqlite3VdbeMakeLabel(v);  /* Jump here for next cycle */
  int addr;
  int iTab;
  int pseudoTab = 0;
  ExprList *pOrderBy = p->pOrderBy;

  int eDest = pDest->eDest;
  int iParm = pDest->iParm;

  int regRow;
  int regRowid;

  iTab = pOrderBy->iECursor;
  regRow = sqlite3GetTempReg(pParse);
  if( eDest==SRT_Output || eDest==SRT_Coroutine ){

#endif
    default: {
      int i;
      assert( eDest==SRT_Output || eDest==SRT_Coroutine ); 
      testcase( eDest==SRT_Output );
      testcase( eDest==SRT_Coroutine );
      for(i=0; i<nColumn; i++){
        assert( regRow!=pDest->iMem+i );
        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
        if( i==0 ){
          sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
        }
      }
      if( eDest==SRT_Output ){
        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
      }else{
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      }
      break;
    }
  }
  sqlite3ReleaseTempReg(pParse, regRow);
  sqlite3ReleaseTempReg(pParse, regRowid);

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );  /* The VDBE already created by calling function */

  /* Create the destination temporary table if necessary
  */
  if( dest.eDest==SRT_EphemTab ){
    assert( p->pEList );
    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, p->pEList->nExpr);
    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
    dest.eDest = SRT_Table;
  }

  /* Make sure all SELECTs in the statement have the same number of elements
  ** in their result sets.
  */

        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */
        assert( p->pRightmost!=p );  /* Can only happen for leftward elements
                                     ** of a 3-way or more compound */
        assert( p->pLimit==0 );      /* Not allowed on leftward elements */
        assert( p->pOffset==0 );     /* Not allowed on leftward elements */
        unionTab = dest.iParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
        */
        unionTab = pParse->nTab++;
        assert( p->pOrderBy==0 );
        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);

      p->pOffset = pOffset;
      p->iLimit = 0;
      p->iOffset = 0;

      /* Convert the data in the temporary table into whatever form
      ** it is that we currently need.
      */
      assert( unionTab==dest.iParm || dest.eDest!=priorOp );
      if( dest.eDest!=priorOp ){
        int iCont, iBreak, iStart;
        assert( p->pEList );
        if( dest.eDest==SRT_Output ){
          Select *pFirst = p;
          while( pFirst->pPrior ) pFirst = pFirst->pPrior;
          generateColumnNames(pParse, 0, pFirst->pEList);

      assert( p->addrOpenEphm[1] == -1 );
      p->addrOpenEphm[1] = addr;
      p->pPrior = 0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      intersectdest.iParm = tab2;
      explainSetInteger(iSub2, pParse->iNextSelectId);
      rc = sqlite3Select(pParse, p, &intersectdest);
      testcase( rc!=SQLITE_OK );
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      if( p->nSelectRow>pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
      sqlite3ExprDelete(db, p->pLimit);

        pLoop->addrOpenEphm[i] = -1;
      }
    }
    sqlite3DbFree(db, pKeyInfo);
  }

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  sqlite3SelectDelete(db, pDelete);
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
**
** The data to be output is contained in pIn->iMem.  There are
** pIn->nMem columns to be output.  pDest is where the output should
** be sent.
**
** regReturn is the number of the register holding the subroutine
** return address.
**
** If regPrev>0 then it is the first register in a vector that
** records the previous output.  mem[regPrev] is a flag that is false

  iContinue = sqlite3VdbeMakeLabel(v);

  /* Suppress duplicates for UNION, EXCEPT, and INTERSECT 
  */
  if( regPrev ){
    int j1, j2;
    j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
    j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
                              (char*)pKeyInfo, p4type);
    sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
    sqlite3VdbeJumpHere(v, j1);
    sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
  }
  if( pParse->db->mallocFailed ) return 0;

  /* Suppress the the first OFFSET entries if there is an OFFSET clause
  */
  codeOffset(v, p, iContinue);

  switch( pDest->eDest ){
    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_EphemTab: {
      int r1 = sqlite3GetTempReg(pParse);
      int r2 = sqlite3GetTempReg(pParse);
      testcase( pDest->eDest==SRT_Table );
      testcase( pDest->eDest==SRT_EphemTab );
      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
      sqlite3ReleaseTempReg(pParse, r2);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      int r1;
      assert( pIn->nMem==1 );
      p->affinity = 
         sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

#if 0  /* Never occurs on an ORDER BY query */
    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }
#endif

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( pIn->nMem==1 );
      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
      /* The LIMIT clause will jump out of the loop for us */
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* The results are stored in a sequence of registers
    ** starting at pDest->iMem.  Then the co-routine yields.
    */
    case SRT_Coroutine: {
      if( pDest->iMem==0 ){
        pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
        pDest->nMem = pIn->nMem;
      }
      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      break;
    }

    /* If none of the above, then the result destination must be
    ** SRT_Output.  This routine is never called with any other
    ** destination other than the ones handled above or SRT_Output.
    **
    ** For SRT_Output, results are stored in a sequence of registers.  
    ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
    ** return the next row of result.
    */
    default: {
      assert( pDest->eDest==SRT_Output );
      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
      break;
    }
  }

  /* Jump to the end of the loop if the LIMIT is reached.
  */
  if( p->iLimit ){

  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, nOrderBy,
                         (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);

  /* Release temporary registers
  */
  if( regPrev ){
    sqlite3ReleaseTempRange(pParse, regPrev, nOrderBy+1);

**
**        The parent and sub-query may contain WHERE clauses. Subject to
**        rules (11), (13) and (14), they may also contain ORDER BY,
**        LIMIT and OFFSET clauses.  The subquery cannot use any compound
**        operator other than UNION ALL because all the other compound
**        operators have an implied DISTINCT which is disallowed by
**        restriction (4).






**
**  (18)  If the sub-query is a compound select, then all terms of the
**        ORDER by clause of the parent must be simple references to 
**        columns of the sub-query.
**
**  (19)  The subquery does not use LIMIT or the outer query does not
**        have a WHERE clause.

    for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
      assert( pSub->pSrc!=0 );
      if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
       || (pSub1->pPrior && pSub1->op!=TK_ALL) 
       || pSub1->pSrc->nSrc<1

      ){
        return 0;
      }
      testcase( pSub1->pSrc->nSrc>1 );
    }

    /* Restriction 18. */

  }
  pTab = p->pSrc->a[0].pTab;
  pExpr = p->pEList->a[0].pExpr;
  assert( pTab && !pTab->pSelect && pExpr );

  if( IsVirtual(pTab) ) return 0;
  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
  if( pAggInfo->nFunc==0 ) return 0;
  if( (pAggInfo->aFunc[0].pFunc->flags&SQLITE_FUNC_COUNT)==0 ) return 0;
  if( pExpr->flags&EP_Distinct ) return 0;

  return pTab;
}

/*

  w.pParse = pParse;
  sqlite3WalkSelect(&w, pSelect);
#endif
}


/*
** This routine sets of a SELECT statement for processing.  The
** following is accomplished:
**
**     *  VDBE Cursor numbers are assigned to all FROM-clause terms.
**     *  Ephemeral Table objects are created for all FROM-clause subqueries.
**     *  ON and USING clauses are shifted into WHERE statements
**     *  Wildcards "*" and "TABLE.*" in result sets are expanded.
**     *  Identifiers in expression are matched to tables.

}

/*
** Reset the aggregate accumulator.
**
** The aggregate accumulator is a set of memory cells that hold
** intermediate results while calculating an aggregate.  This
** routine simply stores NULLs in all of those memory cells.

*/
static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pFunc;
  if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
    return;

**     pDest->eDest    Result
**     ------------    -------------------------------------------
**     SRT_Output      Generate a row of output (using the OP_ResultRow
**                     opcode) for each row in the result set.
**
**     SRT_Mem         Only valid if the result is a single column.
**                     Store the first column of the first result row
**                     in register pDest->iParm then abandon the rest
**                     of the query.  This destination implies "LIMIT 1".
**
**     SRT_Set         The result must be a single column.  Store each
**                     row of result as the key in table pDest->iParm. 
**                     Apply the affinity pDest->affinity before storing
**                     results.  Used to implement "IN (SELECT ...)".
**
**     SRT_Union       Store results as a key in a temporary table pDest->iParm.

**
**     SRT_Except      Remove results from the temporary table pDest->iParm.
**
**     SRT_Table       Store results in temporary table pDest->iParm.
**                     This is like SRT_EphemTab except that the table
**                     is assumed to already be open.
**
**     SRT_EphemTab    Create an temporary table pDest->iParm and store
**                     the result there. The cursor is left open after
**                     returning.  This is like SRT_Table except that
**                     this destination uses OP_OpenEphemeral to create
**                     the table first.
**
**     SRT_Coroutine   Generate a co-routine that returns a new row of
**                     results each time it is invoked.  The entry point
**                     of the co-routine is stored in register pDest->iParm.
**
**     SRT_Exists      Store a 1 in memory cell pDest->iParm if the result
**                     set is not empty.
**
**     SRT_Discard     Throw the results away.  This is used by SELECT
**                     statements within triggers whose only purpose is
**                     the side-effects of functions.
**
** This routine returns the number of errors.  If any errors are

  }else{
    addrSortIndex = -1;
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( pDest->eDest==SRT_EphemTab ){
    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
  }

  /* Set the limiter.
  */
  iEnd = sqlite3VdbeMakeLabel(v);
  p->nSelectRow = (double)LARGEST_INT64;
  computeLimitRegisters(pParse, p, iEnd);

  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    ExprList *pDist = (isDistinct ? p->pEList : 0);

    /* Begin the database scan. */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, pDist, 0);
    if( pWInfo==0 ) goto select_end;
    if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;

    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0);
      if( pWInfo==0 ) goto select_end;
      if( pGroupBy==0 ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenEphemeral table will be
        ** cancelled later because we still need to use the pKeyInfo
        */
        pGroupBy = p->pGroupBy;

        }
  
        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        resetAccumulator(pParse, &sAggInfo);
        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, 0, flag);
        if( pWInfo==0 ){
          sqlite3ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        if( !pMinMax && flag ){
          sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);

    if( pName2->n>0 ){
      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
      goto trigger_cleanup;
    }
    iDb = 1;
    pName = pName1;
  }else{
    /* Figure out the db that the the trigger will be created in */
    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
    if( iDb<0 ){
      goto trigger_cleanup;
    }
  }
  if( !pTableName || db->mallocFailed ){
    goto trigger_cleanup;

    goto update_cleanup;
  }

  /* Begin the database scan
  */
  sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
  pWInfo = sqlite3WhereBegin(
      pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED
  );
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = pWInfo->okOnePass;

  /* Remember the rowid of every item to be updated.
  */
  sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regOldRowid);

** reaches zero, call the xDisconnect() method to delete the object.
*/
SQLITE_PRIVATE void sqlite3VtabUnlock(VTable *pVTab){
  sqlite3 *db = pVTab->db;

  assert( db );
  assert( pVTab->nRef>0 );
  assert( sqlite3SafetyCheckOk(db) );

  pVTab->nRef--;
  if( pVTab->nRef==0 ){
    sqlite3_vtab *p = pVTab->pVtab;
    if( p ){
      p->pModule->xDisconnect(p);
    }

  /* Evaluate the equality constraints
  */
  assert( pIdx->nColumn>=nEq );
  for(j=0; j<nEq; j++){
    int r1;
    int k = pIdx->aiColumn[j];
    pTerm = findTerm(pWC, iCur, k, notReady, pLevel->plan.wsFlags, pIdx);
    if( NEVER(pTerm==0) ) break;
    /* The following true for indices with redundant columns. 
    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
    if( r1!=regBase+j ){
      if( nReg==1 ){

    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */



    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regRowset = 0;                        /* Register for RowSet object */
    int regRowid = 0;                         /* Register holding rowid */
    int iLoopBody = sqlite3VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
   
    pTerm = pLevel->plan.u.pTerm;
    assert( pTerm!=0 );
    assert( pTerm->eOperator==WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList ni pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      struct SrcList_item *origSrc;     /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;

        if( pAndExpr ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY);

        if( pSubWInfo ){

          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            int r;
            r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur, 
                                         regRowid, 0);
            sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset,
                                 sqlite3VdbeCurrentAddr(v)+2, r, iSet);
          }
          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;
























          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite3WhereEnd(pSubWInfo);
        }
      }
    }


    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite3ExprDelete(pParse->db, pAndExpr);
    }
    sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
    sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite3VdbeResolveLabel(v, iLoopBody);

*/
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
  Parse *pParse,        /* The parser context */
  SrcList *pTabList,    /* A list of all tables to be scanned */
  Expr *pWhere,         /* The WHERE clause */
  ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
  ExprList *pDistinct,  /* The select-list for DISTINCT queries - or NULL */
  u16 wctrlFlags        /* One of the WHERE_* flags defined in sqliteInt.h */

){
  int i;                     /* Loop counter */
  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */

      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }
    andFlags &= bestPlan.plan.wsFlags;
    pLevel->plan = bestPlan.plan;
    testcase( bestPlan.plan.wsFlags & WHERE_INDEXED );
    testcase( bestPlan.plan.wsFlags & WHERE_TEMP_INDEX );
    if( bestPlan.plan.wsFlags & (WHERE_INDEXED|WHERE_TEMP_INDEX) ){





      pLevel->iIdxCur = pParse->nTab++;

    }else{
      pLevel->iIdxCur = -1;
    }
    notReady &= ~getMask(pMaskSet, pTabList->a[bestJ].iCursor);
    pLevel->iFrom = (u8)bestJ;
    if( bestPlan.plan.nRow>=(double)1 ){
      pParse->nQueryLoop *= bestPlan.plan.nRow;

    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX)!=0 ){
      constructAutomaticIndex(pParse, pWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
      Index *pIx = pLevel->plan.u.pIdx;
      KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
      int iIdxCur = pLevel->iIdxCur;
      assert( pIx->pSchema==pTab->pSchema );
      assert( iIdxCur>=0 );
      sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
                        (char*)pKey, P4_KEYINFO_HANDOFF);
      VdbeComment((v, "%s", pIx->zName));
    }
    sqlite3CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(pWC->pMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);

  */
  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors that were opened by sqlite3WhereBegin.
  */
  assert( pWInfo->nLevel==1 || pWInfo->nLevel==pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){

    struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    if( (pTab->tabFlags & TF_Ephemeral)==0
     && pTab->pSelect==0
     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
    ){

    ** 
    ** Calls to the code generator in between sqlite3WhereBegin and
    ** sqlite3WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 && !db->mallocFailed){





      int k, j, last;
      VdbeOp *pOp;
      Index *pIdx = pLevel->plan.u.pIdx;

      assert( pIdx!=0 );
      pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
      last = sqlite3VdbeCurrentAddr(v);
      for(k=pWInfo->iTop; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          for(j=0; j<pIdx->nColumn; j++){
            if( pOp->p2==pIdx->aiColumn[j] ){

    }
  }
  sqlite3BtreeLeaveAll(db);
#else
  UNUSED_PARAMETER(db);
#endif
}
















/*
** Close an existing SQLite database
*/
SQLITE_API int sqlite3_close(sqlite3 *db){
  HashElem *i;                    /* Hash table iterator */
  int j;

  if( !db ){
    return SQLITE_OK;
  }
  if( !sqlite3SafetyCheckSickOrOk(db) ){
    return SQLITE_MISUSE_BKPT;
  }
  sqlite3_mutex_enter(db->mutex);

  /* Force xDisconnect calls on all virtual tables */
  disconnectAllVtab(db);

  /* If a transaction is open, the disconnectAllVtab() call above
  ** will not have called the xDisconnect() method on any virtual
  ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
  ** call will do so. We need to do this before the check for active
  ** SQL statements below, as the v-table implementation may be storing
  ** some prepared statements internally.
  */
  sqlite3VtabRollback(db);


  /* If there are any outstanding VMs, return SQLITE_BUSY. */

  if( db->pVdbe ){
    sqlite3Error(db, SQLITE_BUSY, 
        "unable to close due to unfinalised statements");
    sqlite3_mutex_leave(db->mutex);
    return SQLITE_BUSY;
  }
  assert( sqlite3SafetyCheckSickOrOk(db) );






  for(j=0; j<db->nDb; j++){











    Btree *pBt = db->aDb[j].pBt;
    if( pBt && sqlite3BtreeIsInBackup(pBt) ){








      sqlite3Error(db, SQLITE_BUSY, 


          "unable to close due to unfinished backup operation");





      sqlite3_mutex_leave(db->mutex);
      return SQLITE_BUSY;
    }
  }






  /* Free any outstanding Savepoint structures. */
  sqlite3CloseSavepoints(db);

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];

  db->magic = SQLITE_MAGIC_CLOSED;
  sqlite3_mutex_free(db->mutex);
  assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }
  sqlite3_free(db);
  return SQLITE_OK;
}

/*
** Rollback all database files.  If tripCode is not SQLITE_OK, then
** any open cursors are invalidated ("tripped" - as in "tripping a circuit
** breaker") and made to return tripCode if there are any further
** attempts to use that cursor.

SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(Fts3Table*, int, int, int, sqlite3_stmt **);
SQLITE_PRIVATE int sqlite3Fts3ReadLock(Fts3Table *);
SQLITE_PRIVATE int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char **, int*, int*);

SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(Fts3Table *, sqlite3_stmt **);
SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);


SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
SQLITE_PRIVATE int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);









SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *);
SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *, int *);

/* Special values interpreted by sqlite3SegReaderCursor() */
#define FTS3_SEGCURSOR_PENDING        -1
#define FTS3_SEGCURSOR_ALL            -2

    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol, char **); 
SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);

SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(Fts3DeferredToken *, char **, int *);

/* fts3_unicode2.c (functions generated by parsing unicode text files) */
#ifdef SQLITE_ENABLE_FTS4_UNICODE61
SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int, int);
SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int);
SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int);
#endif

  int nToken = 0;
  int nOr = 0;

  /* Allocate a MultiSegReader for each token in the expression. */
  fts3EvalAllocateReaders(pCsr, pCsr->pExpr, &nToken, &nOr, &rc);

  /* Determine which, if any, tokens in the expression should be deferred. */

  if( rc==SQLITE_OK && nToken>1 && pTab->bFts4 ){
    Fts3TokenAndCost *aTC;
    Fts3Expr **apOr;
    aTC = (Fts3TokenAndCost *)sqlite3_malloc(
        sizeof(Fts3TokenAndCost) * nToken
      + sizeof(Fts3Expr *) * nOr * 2
    );

          rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken);
        }
      }

      sqlite3_free(aTC);
    }
  }


  fts3EvalStartReaders(pCsr, pCsr->pExpr, 1, &rc);
  return rc;
}

/*
** Invalidate the current position list for phrase pPhrase.

        bHit = (
            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
         && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
        );
        break;

      default: {

        if( pCsr->pDeferred 
         && (pExpr->iDocid==pCsr->iPrevId || pExpr->bDeferred)
        ){
          Fts3Phrase *pPhrase = pExpr->pPhrase;
          assert( pExpr->bDeferred || pPhrase->doclist.bFreeList==0 );
          if( pExpr->bDeferred ){
            fts3EvalInvalidatePoslist(pPhrase);
          }
          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
          bHit = (pPhrase->doclist.pList!=0);
          pExpr->iDocid = pCsr->iPrevId;
        }else{


          bHit = (pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId);
        }
        break;
      }
    }
  }
  return bHit;