SQLite

  $(TOP)/src/printf.c \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c \
  $(TOP)/src/test3.c \
  $(TOP)/src/test4.c \
  $(TOP)/src/test5.c \
  $(TOP)/src/test6.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbe.c \
  $(TOP)/src/md5.c \
  $(TOP)/src/where.c

# Header files used by all library source files.

	$(LTCOMPILE) -DTCL_USE_STUBS=1 -o $@ -c $(TOP)/src/tclsqlite.c

tclsqlite3:	tclsqlite-shell.lo libsqlite3.la
	$(LTLINK) -o tclsqlite3 tclsqlite-shell.lo \
		 libsqlite3.la $(LIBTCL)

testfixture$(TEXE):	$(TOP)/src/tclsqlite.c libsqlite3.la $(TESTSRC)
	$(LTLINK) -DTCLSH=1 -DSQLITE_TEST=1 $(TEMP_STORE) \
		-o testfixture $(TESTSRC) $(TOP)/src/tclsqlite.c \
		libsqlite3.la $(LIBTCL)


fulltest:	testfixture$(TEXE) sqlite3$(TEXE)
	./testfixture $(TOP)/test/all.test

test:	testfixture$(TEXE) sqlite3$(TEXE)

  $(TOP)/src/printf.c \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c \
  $(TOP)/src/test3.c \
  $(TOP)/src/test4.c \
  $(TOP)/src/test5.c \
  $(TOP)/src/test6.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbe.c \
  $(TOP)/src/md5.c \
  $(TOP)/src/where.c

#  $(TOP)/src/test_async.c 

# Header files used by all library source files.
#
HDR = \
   sqlite3.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/hash.h \
   opcodes.h \

# Rules for building test programs and for running tests
#
tclsqlite3:	$(TOP)/src/tclsqlite.c libsqlite3.a
	$(TCCX) $(TCL_FLAGS) -DTCLSH=1 -o tclsqlite3 \
		$(TOP)/src/tclsqlite.c libsqlite3.a $(LIBTCL) $(THREADLIB)

testfixture$(EXE):	$(TOP)/src/tclsqlite.c libsqlite3.a $(TESTSRC)
	$(TCCX) $(TCL_FLAGS) -DTCLSH=1 -DSQLITE_TEST=1 -o testfixture$(EXE) \

		$(TESTSRC) $(TOP)/src/tclsqlite.c \
		libsqlite3.a $(LIBTCL) $(THREADLIB)

fulltest:	testfixture$(EXE) sqlite3$(EXE)
	./testfixture$(EXE) $(TOP)/test/all.test

test:	testfixture$(EXE) sqlite3$(EXE)

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.282 2006/01/06 13:00:29 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

  }
  p->inTrans = TRANS_NONE;
  p->pSqlite = pSqlite;

  /* Try to find an existing Btree structure opened on zFilename. */
#ifndef SQLITE_OMIT_SHARED_CACHE
  if( pTsd->useSharedData && zFilename && !isMemdb ){
    char *zFullPathname = sqlite3Os.xFullPathname(zFilename);
    if( !zFullPathname ){
      sqliteFree(p);
      return SQLITE_NOMEM;
    }
    for(pBt=pTsd->pBtree; pBt; pBt=pBt->pNext){
      if( 0==strcmp(zFullPathname, sqlite3pager_filename(pBt->pPager)) ){
        p->pBt = pBt;

** This file contains the C functions that implement date and time
** functions for SQLite.  
**
** There is only one exported symbol in this file - the function
** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: date.c,v 1.47 2005/12/09 20:02:05 drh Exp $
**
** NOTES:
**
** SQLite processes all times and dates as Julian Day numbers.  The
** dates and times are stored as the number of days since noon
** in Greenwich on November 24, 4714 B.C. according to the Gregorian
** calendar system.

  memset(p, 0, sizeof(*p));
  if( parseYyyyMmDd(zDate,p)==0 ){
    return 0;
  }else if( parseHhMmSs(zDate, p)==0 ){
    return 0;
  }else if( sqlite3StrICmp(zDate,"now")==0){
    double r;
    sqlite3Os.xCurrentTime(&r);
    p->rJD = r;
    p->validJD = 1;
    return 0;
  }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){
    getValue(zDate, &p->rJD);
    p->validJD = 1;
    return 0;

    int s = x.s + 0.5;
    x.s = s;
  }
  x.tz = 0;
  x.validJD = 0;
  computeJD(&x);
  t = (x.rJD-2440587.5)*86400.0 + 0.5;
  sqlite3Os.xEnterMutex();
  pTm = localtime(&t);
  y.Y = pTm->tm_year + 1900;
  y.M = pTm->tm_mon + 1;
  y.D = pTm->tm_mday;
  y.h = pTm->tm_hour;
  y.m = pTm->tm_min;
  y.s = pTm->tm_sec;
  sqlite3Os.xLeaveMutex();
  y.validYMD = 1;
  y.validHMS = 1;
  y.validJD = 0;
  y.validTZ = 0;
  computeJD(&y);
  return y.rJD - x.rJD;
}

    extern int sqlite3_current_time;  /* See os_XXX.c */
    if( sqlite3_current_time ){
      t = sqlite3_current_time;
    }
  }
#endif

  sqlite3Os.xEnterMutex();
  strftime(zBuf, 20, zFormat, gmtime(&t));
  sqlite3Os.xLeaveMutex();

  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
}
#endif

/*
** This function registered all of the above C functions as SQL

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.316 2006/01/06 06:33:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and

    delay = delays[NDELAY-1];
    prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
  }
  if( prior + delay > timeout ){
    delay = timeout - prior;
    if( delay<=0 ) return 0;
  }
  sqlite3Os.xSleep(delay);
  return 1;
#else
  int timeout = ((sqlite3 *)ptr)->busyTimeout;
  if( (count+1)*1000 > timeout ){
    return 0;
  }
  sqlite3Os.xSleep(1000);
  return 1;
#endif
}

/*
** Invoke the given busy handler.
**

}
int sqlite3OsLockState(OsFile *id){
  return id->pMethod->xLockState(id);
}
int sqlite3OsCheckReservedLock(OsFile *id){
  return id->pMethod->xCheckReservedLock(id);
}
struct sqlite3OsVtbl *sqlite3_os_switch(void){
  return &sqlite3Os;
}

** "os.c") attempt to abstract the underlying operating system so that
** the SQLite library will work on both POSIX and windows systems.
*/
#ifndef _SQLITE_OS_H_
#define _SQLITE_OS_H_

/*
** Figure out if we are dealing with Unix, Windows or MacOS.
**
** N.B. MacOS means Mac Classic (or Carbon). Treat Darwin (OS X) as Unix.
**      The MacOS build is designed to use CodeWarrior (tested with v8)
*/
#if !defined(OS_UNIX) && !defined(OS_ALT)
# define OS_OTHER 0
# ifndef OS_WIN
#   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
#     define OS_WIN 1
#     define OS_UNIX 0
#   else
#     define OS_WIN 0

** prefix to reflect your program's name, so that if your program exits
** prematurely, old temporary files can be easily identified. This can be done
** using -DTEMP_FILE_PREFIX=myprefix_ on the compiler command line.
*/
#ifndef TEMP_FILE_PREFIX
# define TEMP_FILE_PREFIX "sqlite_"
#endif




























































/*
** Forward declarations
*/
typedef struct OsFile OsFile;
typedef struct IoMethod IoMethod;

#endif

#define RESERVED_BYTE     (PENDING_BYTE+1)
#define SHARED_FIRST      (PENDING_BYTE+2)
#define SHARED_SIZE       510

/*
** A single global instance of the following structure holds pointers to 
** the routines that SQLite uses to talk with the underlying operating
** system.  Modify this structure (before using any SQLite API!) to
** accomodate perculiar operating system interfaces or behaviors.
*/
extern struct sqlite3OsVtbl {
  int (*xOpenReadWrite)(const char*, OsFile**, int*);
  int (*xOpenExclusive)(const char*, OsFile**, int);
  int (*xOpenReadOnly)(const char*, OsFile**);

  int (*xDelete)(const char*);
  int (*xFileExists)(const char*);
  char *(*xFullPathname)(const char*);
  int (*xIsDirWritable)(char*);
  int (*xSyncDirectory)(const char*);
  int (*xTempFileName)(char*);

  int (*xRandomSeed)(char*);
  int (*xSleep)(int ms);
  int (*xCurrentTime)(double*);

  void (*xEnterMutex)(void);
  void (*xLeaveMutex)(void);
  int (*xInMutex)(void);
  void *(*xThreadSpecificData)(int);

  void *(*xMalloc)(int);
  void *(*xRealloc)(void *, int);
  void (*xFree)(void *);
  int (*xAllocationSize)(void *);
} sqlite3Os;

/*
** The following API routine returns a pointer to the sqlite3Os global
** variable.  It is probably easier just to reference the global variable
** directly.  This routine is provided for backwards compatibility with
** an older interface design.
*/
struct sqlite3OsVtbl *sqlite3_os_switch(void);


/*
** The following are prototypes of convenience routines that simply
** call the corresponding routines in the OsFile.pMethod virtual
** function table.
*/
int sqlite3OsClose(OsFile**);
int sqlite3OsOpenDirectory(OsFile*, const char*);
int sqlite3OsRead(OsFile*, void*, int amt);
int sqlite3OsWrite(OsFile*, const void*, int amt);
int sqlite3OsSeek(OsFile*, i64 offset);
int sqlite3OsTruncate(OsFile*, i64 size);
int sqlite3OsSync(OsFile*, int);
void sqlite3OsSetFullSync(OsFile *id, int setting);
int sqlite3OsFileHandle(OsFile *id);
int sqlite3OsFileSize(OsFile*, i64 *pSize);
int sqlite3OsLock(OsFile*, int);
int sqlite3OsUnlock(OsFile*, int);
int sqlite3OsLockState(OsFile *id);
int sqlite3OsCheckReservedLock(OsFile *id);





















#endif /* _SQLITE_OS_H_ */

int sqlite3_open_file_count = 0;
#define OpenCounter(X)  sqlite3_open_file_count+=(X)
#else
#define OpenCounter(X)
#endif

/*
** genericMalloc
** genericRealloc
** genericOsFree
** genericAllocationSize
**
** Implementation of the os level dynamic memory allocation interface in terms
** of the standard malloc(), realloc() and free() found in many operating
** systems. No rocket science here.
*/
static void *genericMalloc(int n){
  char *p = (char *)malloc(n+8);
  assert(n>0);
  assert(sizeof(int)<=8);
  if( p ){
    *(int *)p = n;
  }
  return (void *)(p + 8);
}
static void *genericRealloc(void *p, int n){
  char *p2 = ((char *)p - 8);
  assert(n>0);
  p2 = realloc(p2, n+8);
  if( p2 ){
    *(int *)p2 = n;
  }
  return (void *)((char *)p2 + 8);
}
static void genericFree(void *p){
  assert(p);
  free((void *)((char *)p - 8));
}
static int genericAllocationSize(void *p){
  return p ? *(int *)((char *)p - 8) : 0;
}

******************************************************************************
**
** This file contains code that is specific to Unix systems.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_UNIX              /* This file is used on unix only */

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
** large file support, or if the OS is windows, these should be no-ops.
**
** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
** on the compiler command line.  This is necessary if you are compiling

  unsigned char fullSync;   /* Use F_FULLSYNC if available */
  int dirfd;                /* File descriptor for the directory */
#ifdef SQLITE_UNIX_THREADS
  pthread_t tid;            /* The thread authorized to use this OsFile */
#endif
};


















/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO

  pTsd->disableReleaseMemory = 0;
  return rc;
}

/*
** Delete the named file
*/
static int unixDelete(const char *zFilename){
  unlink(zFilename);
  return SQLITE_OK;
}

/*
** Return TRUE if the named file exists.
*/
static int unixFileExists(const char *zFilename){
  return access(zFilename, 0)==0;
}

/* Forward declaration */
static int allocateUnixFile(unixFile *pInit, OsFile **pId);

/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
** and *pReadonly is set to 0 if the file was opened for reading and
** writing or 1 if the file was opened read-only.  The function returns
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int unixOpenReadWrite(
  const char *zFilename,
  OsFile **pId,
  int *pReadonly
){
  int rc;
  unixFile f;


  assert( 0==*pId );
  f.dirfd = -1;
  SET_THREADID(&f);
  f.h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY,
                          SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( f.h<0 ){
#ifdef EISDIR
    if( errno==EISDIR ){
      return SQLITE_CANTOPEN;
    }
#endif
    f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
    if( f.h<0 ){
      return SQLITE_CANTOPEN; 
    }
    *pReadonly = 1;
  }else{
    *pReadonly = 0;
  }
  sqlite3Os.xEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3Os.xLeaveMutex();
  if( rc ){
    close(f.h);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;
  TRACE3("OPEN    %-3d %s\n", f.h, zFilename);
  return allocateUnixFile(&f, pId);

** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
  int rc;
  unixFile f;


  assert( 0==*pId );
  if( access(zFilename, 0)==0 ){
    return SQLITE_CANTOPEN;
  }
  SET_THREADID(&f);
  f.dirfd = -1;
  f.h = open(zFilename,
                O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY,
                SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( f.h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3Os.xEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3Os.xLeaveMutex();
  if( rc ){
    close(f.h);
    unlink(zFilename);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;
  if( delFlag ){
    unlink(zFilename);
  }
  TRACE3("OPEN-EX %-3d %s\n", f.h, zFilename);
  return allocateUnixFile(&f, pId);
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenReadOnly(const char *zFilename, OsFile **pId){
  int rc;
  unixFile f;


  assert( 0==*pId );
  SET_THREADID(&f);
  f.dirfd = -1;
  f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
  if( f.h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3Os.xEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3Os.xLeaveMutex();
  if( rc ){
    close(f.h);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;
  TRACE3("OPEN-RO %-3d %s\n", f.h, zFilename);

*/
char *sqlite3_temp_directory = 0;

/*
** Create a temporary file name in zBuf.  zBuf must be big enough to
** hold at least SQLITE_TEMPNAME_SIZE characters.
*/
static int unixTempFileName(char *zBuf){
  static const char *azDirs[] = {
     0,
     "/var/tmp",
     "/usr/tmp",
     "/tmp",
     ".",
  };

  return SQLITE_OK; 
}

/*
** Check that a given pathname is a directory and is writable 
**
*/
static int unixIsDirWritable(char *zBuf){
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
  struct stat buf;
  if( zBuf==0 ) return 0;
  if( zBuf[0]==0 ) return 0;
  if( stat(zBuf, &buf) ) return 0;
  if( !S_ISDIR(buf.st_mode) ) return 0;
  if( access(zBuf, 07) ) return 0;

** Sync the directory zDirname. This is a no-op on operating systems other
** than UNIX.
**
** This is used to make sure the master journal file has truely been deleted
** before making changes to individual journals on a multi-database commit.
** The F_FULLFSYNC option is not needed here.
*/
static int unixSyncDirectory(const char *zDirname){
#ifdef SQLITE_DISABLE_DIRSYNC
  return SQLITE_OK;
#else
  int fd;
  int r;
  SimulateIOError(SQLITE_IOERR);
  fd = open(zDirname, O_RDONLY|O_BINARY, 0);

*/
static int unixCheckReservedLock(OsFile *id){
  int r = 0;
  unixFile *pFile = (unixFile*)id;

  assert( pFile );
  if( CHECK_THREADID(pFile) ) return SQLITE_MISUSE;
  sqlite3Os.xEnterMutex(); /* Because pFile->pLock is shared across threads */

  /* Check if a thread in this process holds such a lock */
  if( pFile->pLock->locktype>SHARED_LOCK ){
    r = 1;
  }

  /* Otherwise see if some other process holds it.
  */
  if( !r ){
    struct flock lock;
    lock.l_whence = SEEK_SET;
    lock.l_start = RESERVED_BYTE;
    lock.l_len = 1;
    lock.l_type = F_WRLCK;
    fcntl(pFile->h, F_GETLK, &lock);
    if( lock.l_type!=F_UNLCK ){
      r = 1;
    }
  }
  
  sqlite3Os.xLeaveMutex();
  TRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);

  return r;
}

#ifdef SQLITE_DEBUG
/*

  TRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", pFile->h,
      locktypeName(locktype), locktypeName(pFile->locktype),
      locktypeName(pLock->locktype), pLock->cnt , getpid());
  if( CHECK_THREADID(pFile) ) return SQLITE_MISUSE;

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3Os.xEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    TRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
            locktypeName(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 );

  /* This mutex is needed because pFile->pLock is shared across threads
  */
  sqlite3Os.xEnterMutex();

  /* If some thread using this PID has a lock via a different OsFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->locktype!=pLock->locktype && 
          (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
  ){

    pLock->locktype = locktype;
  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
    pLock->locktype = PENDING_LOCK;
  }

end_lock:
  sqlite3Os.xLeaveMutex();
  TRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
      rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype

      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());
  if( CHECK_THREADID(pFile) ) return SQLITE_MISUSE;

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  sqlite3Os.xEnterMutex();
  pLock = pFile->pLock;
  assert( pLock->cnt!=0 );
  if( pFile->locktype>SHARED_LOCK ){
    assert( pLock->locktype==pFile->locktype );
    if( locktype==SHARED_LOCK ){
      lock.l_type = F_RDLCK;
      lock.l_whence = SEEK_SET;

        close(pOpen->aPending[i]);
      }
      sqliteFree(pOpen->aPending);
      pOpen->nPending = 0;
      pOpen->aPending = 0;
    }
  }
  sqlite3Os.xLeaveMutex();
  pFile->locktype = locktype;
  return rc;
}

/*
** Close a file.
*/
static int unixClose(OsFile **pId){
  SqliteTsd *pTsd = sqlite3Tsd();
  unixFile *id = (unixFile*)*pId;
  if( !id ) return SQLITE_OK;
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  unixUnlock(*pId, NO_LOCK);
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3Os.xEnterMutex();

  /* Disable the sqlite3_release_memory() function */
  assert( !pTsd->disableReleaseMemory );
  pTsd->disableReleaseMemory = 1;

  if( id->pOpen->nLock ){
    /* If there are outstanding locks, do not actually close the file just

  }
  releaseLockInfo(id->pLock);
  releaseOpenCnt(id->pOpen);

  /* Disable the sqlite3_release_memory() function */
  pTsd->disableReleaseMemory = 0;

  sqlite3Os.xLeaveMutex();
  id->isOpen = 0;
  TRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqliteFree(id);
  *pId = 0;
  return SQLITE_OK;
}

/*
** Turn a relative pathname into a full pathname.  Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
** The calling function is responsible for freeing this space once it
** is no longer needed.
*/
static char *unixFullPathname(const char *zRelative){
  char *zFull = 0;
  if( zRelative[0]=='/' ){
    sqlite3SetString(&zFull, zRelative, (char*)0);
  }else{
    char *zBuf = sqliteMalloc(5000);
    if( zBuf==0 ){
      return 0;

/*
** Get information to seed the random number generator.  The seed
** is written into the buffer zBuf[256].  The calling function must
** supply a sufficiently large buffer.
*/
static int unixRandomSeed(char *zBuf){
  /* We have to initialize zBuf to prevent valgrind from reporting
  ** errors.  The reports issued by valgrind are incorrect - we would
  ** prefer that the randomness be increased by making use of the
  ** uninitialized space in zBuf - but valgrind errors tend to worry
  ** some users.  Rather than argue, it seems easier just to initialize
  ** the whole array and silence valgrind, even if that means less randomness
  ** in the random seed.

#endif
  return SQLITE_OK;
}

/*
** Sleep for a little while.  Return the amount of time slept.
*/
static int unixSleep(int ms){
#if defined(HAVE_USLEEP) && HAVE_USLEEP
  usleep(ms*1000);
  return ms;
#else
  sleep((ms+999)/1000);
  return 1000*((ms+999)/1000);
#endif

** The following pair of routine implement mutual exclusion for
** multi-threaded processes.  Only a single thread is allowed to
** executed code that is surrounded by EnterMutex() and LeaveMutex().
**
** SQLite uses only a single Mutex.  There is not much critical
** code and what little there is executes quickly and without blocking.
*/
static void unixEnterMutex(){
#ifdef SQLITE_UNIX_THREADS
  pthread_mutex_lock(&mutex);
#endif
  assert( !inMutex );
  inMutex = 1;
}
static void unixLeaveMutex(){
  assert( inMutex );
  inMutex = 0;
#ifdef SQLITE_UNIX_THREADS
  pthread_mutex_unlock(&mutex);
#endif
}

/*
** Return TRUE if we are currently within the mutex and FALSE if not.
** This routine is intended for sanity checking only.  It is designed
** for use in an assert() to verify that the mutex is held or not held
** in certain routines.
*/
static int unixInMutex(){
  return inMutex;
}

/*
** This function is called automatically when a thread exists to delete
** the threads SqliteTsd structure. 
**
** Because the SqliteTsd structure is required by higher level routines
** such as sqliteMalloc() we use OsFree() and OsMalloc() directly to
** allocate the thread specific data.
*/
#ifdef SQLITE_UNIX_THREADS
static void deleteTsd(void *pTsd){
  sqlite3Os.xFree(pTsd);
}
#endif

/* 
** The first time this function is called from a specific thread, nByte 
** bytes of data area are allocated and zeroed. A pointer to the new 
** allocation is returned to the caller. 
**
** Each subsequent call to this function from the thread returns the same
** pointer. The argument is ignored in this case.
*/
static void *unixThreadSpecificData(int nByte){
#ifdef SQLITE_UNIX_THREADS
  static pthread_key_t key;
  static int keyInit = 0;
  void *pTsd;

  if( !keyInit ){
    sqlite3Os.xEnterMutex();
    if( !keyInit ){
      int rc;
      rc = pthread_key_create(&key, deleteTsd);
      if( rc ){
        return 0;
      }
      keyInit = 1;
    }
    sqlite3Os.xLeaveMutex();
  }

  pTsd = pthread_getspecific(key);
  if( !pTsd ){
    pTsd = sqlite3Os.xMalloc(nByte);
    if( pTsd ){
      memset(pTsd, 0, nByte);
      pthread_setspecific(key, pTsd);
    }
  }
  return pTsd;
#else
  static void *pTsd = 0;
  if( !pTsd ){
    pTsd = sqlite3Os.xMalloc(nByte);
    if( pTsd ){
      memset(pTsd, 0, nByte);
    }
  }
  return pTsd;
#endif
}

/*
** The following variable, if set to a non-zero value, becomes the result
** returned from sqlite3Os.xCurrentTime().  This is used for testing.
*/
#ifdef SQLITE_TEST
int sqlite3_current_time = 0;
#endif

/*
** 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 unixCurrentTime(double *prNow){
#ifdef NO_GETTOD
  time_t t;
  time(&t);
  *prNow = t/86400.0 + 2440587.5;
#else
  struct timeval sNow;
  struct timezone sTz;  /* Not used */
  gettimeofday(&sNow, &sTz);
  *prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_usec/86400000000.0;
#endif
#ifdef SQLITE_TEST
  if( sqlite3_current_time ){
    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
  }
#endif
  return 0;
}

/* Macro used to comment out routines that do not exists when there is
** no disk I/O */
#ifdef SQLITE_OMIT_DISKIO
# define IF_DISKIO(X)  0
#else
# define IF_DISKIO(X)  X
#endif

/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3OsVtbl sqlite3Os = {
  IF_DISKIO( unixOpenReadWrite ),
  IF_DISKIO( unixOpenExclusive ),
  IF_DISKIO( unixOpenReadOnly ),
  IF_DISKIO( unixDelete ),
  IF_DISKIO( unixFileExists ),
  IF_DISKIO( unixFullPathname ),
  IF_DISKIO( unixIsDirWritable ),
  IF_DISKIO( unixSyncDirectory ),
  IF_DISKIO( unixTempFileName ),
  unixRandomSeed,
  unixSleep,
  unixCurrentTime,
  unixEnterMutex,
  unixLeaveMutex,
  unixInMutex,
  unixThreadSpecificData,
  genericMalloc,
  genericRealloc,
  genericFree,
  genericAllocationSize
};



#endif /* OS_UNIX */

  return zFilename;
}


/*
** Delete the named file
*/
static int winDelete(const char *zFilename){
  WCHAR *zWide = utf8ToUnicode(zFilename);
  if( zWide ){
    DeleteFileW(zWide);
    sqliteFree(zWide);
  }else{
    DeleteFileA(zFilename);
  }
  TRACE2("DELETE \"%s\"\n", zFilename);
  return SQLITE_OK;
}

/*
** Return TRUE if the named file exists.
*/
static int winFileExists(const char *zFilename){
  int exists = 0;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  if( zWide ){
    exists = GetFileAttributesW(zWide) != 0xffffffff;
    sqliteFree(zWide);
  }else{
    exists = GetFileAttributesA(zFilename) != 0xffffffff;

** and *pReadonly is set to 0 if the file was opened for reading and
** writing or 1 if the file was opened read-only.  The function returns
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int winOpenReadWrite(
  const char *zFilename,
  OsFile **pId,
  int *pReadonly
){
  winFile f;
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);

** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
  winFile f;
  HANDLE h;
  int fileflags;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( *pId == 0 );
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenReadOnly(const char *zFilename, OsFile **pId){
  winFile f;
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( *pId==0 );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ,

*/
char *sqlite3_temp_directory = 0;

/*
** Create a temporary file name in zBuf.  zBuf must be big enough to
** hold at least SQLITE_TEMPNAME_SIZE characters.
*/
static int winTempFileName(char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  int i, j;
  char zTempPath[SQLITE_TEMPNAME_SIZE];
  if( sqlite3_temp_directory ){

    sprintf(zBuf, "%s\\"TEMP_FILE_PREFIX, zTempPath);
    j = strlen(zBuf);
    sqlite3Randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
    if( !sqlite3Os.xFileExists(zBuf) ) break;
  }
  TRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** Close a file.

  }
}

/*
** Sync the directory zDirname. This is a no-op on operating systems other
** than UNIX.
*/
static int winSyncDirectory(const char *zDirname){
  SimulateIOError(SQLITE_IOERR);
  return SQLITE_OK;
}

/*
** Truncate an open file to a specified size
*/

}

#ifndef SQLITE_OMIT_PAGER_PRAGMAS
/*
** Check that a given pathname is a directory and is writable 
**
*/
static int winIsDirWritable(char *zDirname){
  int fileAttr;
  WCHAR *zWide;
  if( zDirname==0 ) return 0;
  if( !isNT() && strlen(zDirname)>MAX_PATH ) return 0;
  zWide = utf8ToUnicode(zDirname);
  if( zWide ){
    fileAttr = GetFileAttributesW(zWide);

/*
** Turn a relative pathname into a full pathname.  Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
** The calling function is responsible for freeing this space once it
** is no longer needed.
*/
static char *winFullPathname(const char *zRelative){
  char *zNotUsed;
  char *zFull;
  WCHAR *zWide;
  int nByte;
#ifdef __CYGWIN__
  nByte = strlen(zRelative) + MAX_PATH + 1001;
  zFull = sqliteMalloc( nByte );

  if( pNew==0 ){
    CloseHandle(pInit->h);
    *pId = 0;
    return SQLITE_NOMEM;
  }else{
    *pNew = *pInit;
    pNew->pMethod = &sqlite3WinIoMethod;
    *pId = pNew;
    return SQLITE_OK;
  }
}


#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
** Everything above deals with file I/O.  Everything that follows deals
** with other miscellanous aspects of the operating system interface
****************************************************************************/

/*
** Get information to seed the random number generator.  The seed
** is written into the buffer zBuf[256].  The calling function must
** supply a sufficiently large buffer.
*/
static int winRandomSeed(char *zBuf){
  /* We have to initialize zBuf to prevent valgrind from reporting
  ** errors.  The reports issued by valgrind are incorrect - we would
  ** prefer that the randomness be increased by making use of the
  ** uninitialized space in zBuf - but valgrind errors tend to worry
  ** some users.  Rather than argue, it seems easier just to initialize
  ** the whole array and silence valgrind, even if that means less randomness
  ** in the random seed.
  **
  ** When testing, initializing zBuf[] to zero is all we do.  That means
  ** that we always use the same random number sequence.* This makes the
  ** tests repeatable.
  */
  memset(zBuf, 0, 256);
  GetSystemTime((LPSYSTEMTIME)zBuf);
  return SQLITE_OK;
}

/*
** Sleep for a little while.  Return the amount of time slept.
*/
static int winSleep(int ms){
  Sleep(ms);
  return ms;
}

/*
** Static variables used for thread synchronization
*/
static int inMutex = 0;
#ifdef SQLITE_W32_THREADS
  static CRITICAL_SECTION cs;
#endif

/*
** The following pair of routine implement mutual exclusion for
** multi-threaded processes.  Only a single thread is allowed to
** executed code that is surrounded by EnterMutex() and LeaveMutex().
**
** SQLite uses only a single Mutex.  There is not much critical
** code and what little there is executes quickly and without blocking.
*/
static void winEnterMutex(){
#ifdef SQLITE_W32_THREADS
  static int isInit = 0;
  while( !isInit ){
    static long lock = 0;
    if( InterlockedIncrement(&lock)==1 ){
      InitializeCriticalSection(&cs);
      isInit = 1;
    }else{
      Sleep(1);
    }
  }
  EnterCriticalSection(&cs);
#endif
  assert( !inMutex );
  inMutex = 1;
}
static void winLeaveMutex(){
  assert( inMutex );
  inMutex = 0;
#ifdef SQLITE_W32_THREADS
  LeaveCriticalSection(&cs);
#endif
}

/*
** Return TRUE if we are currently within the mutex and FALSE if not.
** This routine is intended for sanity checking only.  It is designed
** for use in an assert() to verify that the mutex is held or not held
** in certain routines.
*/
static int winInMutex(){
  return inMutex;
}


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

/*
** 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 winCurrentTime(double *prNow){
  FILETIME ft;
  /* FILETIME structure is a 64-bit value representing the number of 
     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). 
  */
  double now;
  GetSystemTimeAsFileTime( &ft );
  now = ((double)ft.dwHighDateTime) * 4294967296.0; 

** The first time this function is called from a specific thread, nByte 
** bytes of data area are allocated and zeroed. A pointer to the new 
** allocation is returned to the caller. 
**
** Each subsequent call to this function from the thread returns the same
** pointer. The argument is ignored in this case.
*/
static void *winThreadSpecificData(int nByte){
  static void *pTsd = 0;
  static int key;
  static int keyInit = 0;

  if( !keyInit ){
    sqlite3Os.xEnterMutex();
    if( !keyInit ){
      key = TlsAlloc();
      if( key==0xffffffff ){
        sqlite3Os.xLeaveMutex();
        return 0;
      }
      keyInit = 1;
    }
    sqlite3Os.xLeaveMutex();
  }
  pTsd = TlsGetValue(key);
  if( !pTsd ){
    pTsd = sqlite3Os.xMalloc(nByte);
    if( pTsd ){
      memset(pTsd, 0, nByte);
      TlsSetValue(key, pTsd);
    }
  }
  return pTsd;
}

/* Macro used to comment out routines that do not exists when there is
** no disk I/O
*/
#ifdef SQLITE_OMIT_DISKIO
# define IF_DISKIO(X)  0
#else
# define IF_DISKIO(X)  X
#endif

/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3OsVtbl sqlite3Os = {
  IF_DISKIO( winOpenReadWrite ),
  IF_DISKIO( winOpenExclusive ),
  IF_DISKIO( winOpenReadOnly ),
  IF_DISKIO( winDelete ),
  IF_DISKIO( winFileExists ),
  IF_DISKIO( winFullPathname ),
  IF_DISKIO( winIsDirWritable ),
  IF_DISKIO( winSyncDirectory ),
  IF_DISKIO( winTempFileName ),
  winRandomSeed,
  winSleep,
  winCurrentTime,
  winEnterMutex,
  winLeaveMutex,
  winInMutex,
  winThreadSpecificData,
  genericMalloc,
  genericRealloc,
  genericFree,
  genericAllocationSize
};

#endif /* OS_WIN */

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.230 2006/01/05 13:48:29 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

  if( pPager->stmtOpen ){
    sqlite3OsClose(&pPager->stfd);
    pPager->stmtOpen = 0;
  }
  if( pPager->journalOpen ){
    sqlite3OsClose(&pPager->jfd);
    pPager->journalOpen = 0;
    sqlite3Os.xDelete(pPager->zJournal);
    sqliteFree( pPager->aInJournal );
    pPager->aInJournal = 0;
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      pPg->inJournal = 0;
      pPg->dirty = 0;
      pPg->needSync = 0;
#ifdef SQLITE_CHECK_PAGES

  OsFile *master = 0;
  char *zMasterJournal = 0; /* Contents of master journal file */
  i64 nMasterJournal;       /* Size of master journal file */

  /* Open the master journal file exclusively in case some other process
  ** is running this routine also. Not that it makes too much difference.
  */
  rc = sqlite3Os.xOpenReadOnly(zMaster, &master);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  master_open = 1;
  rc = sqlite3OsFileSize(master, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;

  if( nMasterJournal>0 ){
    char *zJournal;

      goto delmaster_out;
    }
    rc = sqlite3OsRead(master, zMasterJournal, nMasterJournal);
    if( rc!=SQLITE_OK ) goto delmaster_out;

    zJournal = zMasterJournal;
    while( (zJournal-zMasterJournal)<nMasterJournal ){
      if( sqlite3Os.xFileExists(zJournal) ){
        /* One of the journals pointed to by the master journal exists.
        ** Open it and check if it points at the master journal. If
        ** so, return without deleting the master journal file.
        */
        OsFile *journal = 0;
        int c;

        rc = sqlite3Os.xOpenReadOnly(zJournal, &journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        rc = readMasterJournal(journal, &zMasterPtr);
        sqlite3OsClose(&journal);
        if( rc!=SQLITE_OK ){

          goto delmaster_out;
        }
      }
      zJournal += (strlen(zJournal)+1);
    }
  }
  
  sqlite3Os.xDelete(zMaster);

delmaster_out:
  if( zMasterJournal ){
    sqliteFree(zMasterJournal);
  }  
  if( master_open ){
    sqlite3OsClose(&master);

  /* Read the master journal name from the journal, if it is present.
  ** If a master journal file name is specified, but the file is not
  ** present on disk, then the journal is not hot and does not need to be
  ** played back.
  */
  rc = readMasterJournal(pPager->jfd, &zMaster);
  assert( rc!=SQLITE_DONE );
  if( rc!=SQLITE_OK || (zMaster && !sqlite3Os.xFileExists(zMaster)) ){
    sqliteFree(zMaster);
    zMaster = 0;
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
    goto end_playback;
  }
  sqlite3OsSeek(pPager->jfd, 0);
  pPager->journalOff = 0;

*/
static int sqlite3pager_opentemp(char *zFile, OsFile **pFd){
  int cnt = 8;
  int rc;
  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
  do{
    cnt--;
    sqlite3Os.xTempFileName(zFile);
    rc = sqlite3Os.xOpenExclusive(zFile, pFd, 1);
  }while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM );
  return rc;
}

/*
** Create a new page cache and put a pointer to the page cache in *ppPager.
** The file to be cached need not exist.  The file is not locked until

#ifndef SQLITE_OMIT_MEMORYDB
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      zFullPathname = sqliteStrDup("");
    }else
#endif
    {
      zFullPathname = sqlite3Os.xFullPathname(zFilename);
      if( zFullPathname ){
        rc = sqlite3Os.xOpenReadWrite(zFullPathname, &fd, &readOnly);
      }
    }
  }else{
    rc = sqlite3pager_opentemp(zTemp, &fd);
    zFilename = zTemp;
    zFullPathname = sqlite3Os.xFullPathname(zFilename);
    if( rc==SQLITE_OK ){
      tempFile = 1;
    }
  }

  /* Allocate the Pager structure. As part of the same allocation, allocate
  ** space for the full paths of the file, directory and journal 

  sqliteFree(pPager->aInJournal);
  if( pPager->stmtOpen ){
    sqlite3OsClose(&pPager->stfd);
  }
  sqlite3OsClose(&pPager->fd);
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqlite3Os.xDelete(pPager->zFilename);
  ** }
  */

#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** SqliteTsd.pPager.
  */

**
** If the current size of the database file is 0 but a journal file
** exists, that is probably an old journal left over from a prior
** database with the same name.  Just delete the journal.
*/
static int hasHotJournal(Pager *pPager){
  if( !pPager->useJournal ) return 0;
  if( !sqlite3Os.xFileExists(pPager->zJournal) ) return 0;
  if( sqlite3OsCheckReservedLock(pPager->fd) ) return 0;
  if( sqlite3pager_pagecount(pPager)==0 ){
    sqlite3Os.xDelete(pPager->zJournal);
    return 0;
  }else{
    return 1;
  }
}

/*

  SqliteTsd *pTsd = sqlite3Tsd();
  Pager *p;
  int nReleased = 0;
  int i;

  /* If the disableReleaseMemory memory flag is set, this operation is
  ** a no-op; zero bytes of memory are freed. The flag is set before
  ** malloc() is called while the global mutex (see sqlite3Os.xEnterMutex) 
  ** is held. Because some of the code invoked by this function may also
  ** try to obtain the mutex, proceding may cause a deadlock. 
  */
  if( pTsd->disableReleaseMemory ){
    return 0;
  }

       ** we are unable to open the journal file. 
       **
       ** The journal file does not need to be locked itself.  The
       ** journal file is never open unless the main database file holds
       ** a write lock, so there is never any chance of two or more
       ** processes opening the journal at the same time.
       */
       rc = sqlite3Os.xOpenReadOnly(pPager->zJournal, &pPager->jfd);
       if( rc!=SQLITE_OK ){
         sqlite3OsUnlock(pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;

  assert( pPager->aInJournal==0 );
  sqlite3pager_pagecount(pPager);
  pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInJournal==0 ){
    rc = SQLITE_NOMEM;
    goto failed_to_open_journal;
  }
  rc = sqlite3Os.xOpenExclusive(pPager->zJournal, &pPager->jfd,
                                 pPager->tempFile);
  pPager->journalOff = 0;
  pPager->setMaster = 0;
  pPager->journalHdr = 0;
  if( rc!=SQLITE_OK ){
    goto failed_to_open_journal;
  }

  pPager->aInJournal = 0;
  if( rc==SQLITE_NOMEM ){
    /* If this was a malloc() failure, then we will not be closing the pager
    ** file. So delete any journal file we may have just created. Otherwise,
    ** the system will get confused, we have a read-lock on the file and a
    ** mysterious journal has appeared in the filesystem.
    */
    sqlite3Os.xDelete(pPager->zJournal);
  }else{
    sqlite3OsUnlock(pPager->fd, NO_LOCK);
    pPager->state = PAGER_UNLOCK;
  }
  return rc;
}

/*
** 2003 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.108 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/

      if( sqlite3_temp_directory ){
        sqlite3VdbeSetNumCols(v, 1);
        sqlite3VdbeSetColName(v, 0, "temp_store_directory", P3_STATIC);
        sqlite3VdbeOp3(v, OP_String8, 0, 0, sqlite3_temp_directory, 0);
        sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
      }
    }else{
      if( zRight[0] && !sqlite3Os.xIsDirWritable(zRight) ){
        sqlite3ErrorMsg(pParse, "not a writable directory");
        goto pragma_out;
      }
      if( TEMP_STORE==0
       || (TEMP_STORE==1 && db->temp_store<=1)
       || (TEMP_STORE==2 && db->temp_store==1)
      ){

*************************************************************************
** This file contains code to implement a pseudo-random number
** generator (PRNG) for SQLite.
**
** Random numbers are used by some of the database backends in order
** to generate random integer keys for tables or random filenames.
**
** $Id: random.c,v 1.14 2005/11/30 03:20:32 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"


/*
** Get a single 8-bit random value from the RC4 PRNG.  The Mutex

  ** number generator) not as an encryption device.
  */
  if( !prng.isInit ){
    int i;
    char k[256];
    prng.j = 0;
    prng.i = 0;
    sqlite3Os.xRandomSeed(k);
    for(i=0; i<256; i++){
      prng.s[i] = i;
    }
    for(i=0; i<256; i++){
      prng.j += prng.s[i] + k[i];
      t = prng.s[prng.j];
      prng.s[prng.j] = prng.s[i];

}

/*
** Return N random bytes.
*/
void sqlite3Randomness(int N, void *pBuf){
  unsigned char *zBuf = pBuf;
  sqlite3Os.xEnterMutex();
  while( N-- ){
    *(zBuf++) = randomByte();
  }
  sqlite3Os.xLeaveMutex();
}

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** A TCL Interface to SQLite
**
** $Id: tclsqlite.c,v 1.146 2006/01/06 03:29:58 drh Exp $
*/
#ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */

#include "sqliteInt.h"
#include "hash.h"
#include "tcl.h"
#include <stdlib.h>

  {
    extern int Sqlitetest1_Init(Tcl_Interp*);
    extern int Sqlitetest2_Init(Tcl_Interp*);
    extern int Sqlitetest3_Init(Tcl_Interp*);
    extern int Sqlitetest4_Init(Tcl_Interp*);
    extern int Sqlitetest5_Init(Tcl_Interp*);
    extern int Sqlitetest6_Init(Tcl_Interp*);
    extern int Sqlitetestasync_Init(Tcl_Interp*);
    extern int Md5_Init(Tcl_Interp*);
    extern int Sqlitetestsse_Init(Tcl_Interp*);

    Sqlitetest1_Init(interp);
    Sqlitetest2_Init(interp);
    Sqlitetest3_Init(interp);
    Sqlitetest4_Init(interp);
    Sqlitetest5_Init(interp);
    Sqlitetest6_Init(interp);
    Sqlitetestasync_Init(interp);
    Md5_Init(interp);
#ifdef SQLITE_SSE
    Sqlitetestsse_Init(interp);
#endif
  }
#endif
  if( argc>=2 || TCLSH==2 ){

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.180 2006/01/05 15:50:07 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename", 0);
    return TCL_ERROR;
  }

  rc = sqlite3Os.xOpenReadWrite(Tcl_GetString(objv[1]), &pFile, &dummy);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  makePointerStr(interp, zBuf, pFile);
  Tcl_SetResult(interp, zBuf, 0);
  return TCL_ERROR;

  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  char zFile[SQLITE_TEMPNAME_SIZE];
  int rc;

  rc = sqlite3Os.xTempFileName(zFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  Tcl_AppendResult(interp, zFile, 0);
  return TCL_OK;
}

#endif

#ifdef SQLITE_OMIT_CONFLICT_CLAUSE
  Tcl_SetVar2(interp, "sqlite_options", "conflict", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "conflict", "1", TCL_GLOBAL_ONLY);
#endif







#ifdef SQLITE_OMIT_DATETIME_FUNCS
  Tcl_SetVar2(interp, "sqlite_options", "datetime", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "datetime", "1", TCL_GLOBAL_ONLY);
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.38 2005/11/30 03:20:32 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

  int readOnly = 0;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;
  rc = sqlite3Os.xOpenReadWrite(argv[2], &fd, &readOnly);
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;
  rc = sqlite3OsSeek(fd, offset);

** is used to test the ability of SQLite to recover from those situations.
*/
#if SQLITE_TEST          /* This file is used for the testing only */
#include "sqliteInt.h"
#include "os.h"
#include "tcl.h"

/*
** A copy of the original sqlite3Os structure
*/
static struct sqlite3OsVtbl origOs;

/*
** crashFile is a subclass of OsFile that is taylored for the
** crash test module.
*/
typedef struct crashFile crashFile;
struct crashFile {
  IoMethod const *pMethod; /* Must be first */

static int iCrashDelay = 0;
static char zCrashFile[500];

/*
** Set the value of the two crash parameters.
*/
static void setCrashParams(int iDelay, char const *zFile){
  sqlite3Os.xEnterMutex();
  assert( strlen(zFile)<sizeof(zCrashFile) );
  strcpy(zCrashFile, zFile);
  iCrashDelay = iDelay;
  sqlite3Os.xLeaveMutex();
}

/*
** File zPath is being sync()ed. Return non-zero if this should
** cause a crash.
*/
static int crashRequired(char const *zPath){
  int r;
  int n;
  sqlite3Os.xEnterMutex();
  n = strlen(zCrashFile);
  if( zCrashFile[n-1]=='*' ){
    n--;
  }else if( strlen(zPath)>n ){
    n = strlen(zPath);
  }
  r = 0;
  if( iCrashDelay>0 && strncmp(zPath, zCrashFile, n)==0 ){
    iCrashDelay--;
    if( iCrashDelay<=0 ){
      r = 1;
    }
  }
  sqlite3Os.xLeaveMutex();
  return r;
}

/*
** A list of all open files.
*/
static crashFile *pAllFiles = 0;

  int rc = sqlite3OsFileSize(pFile->pBase, pSize);
  if( rc==SQLITE_OK && pSize && *pSize<pFile->nMaxWrite ){
    *pSize = pFile->nMaxWrite;
  }
  return rc;
}






/*
** The three functions used to open files. All that is required is to
** initialise the os_test.c specific fields and then call the corresponding
** os_unix.c function to really open the file.
*/
static int crashOpenReadWrite(const char *zFilename, OsFile **pId,int *pRdonly){
  OsFile *pBase = 0;



  int rc = origOs.xOpenReadWrite(zFilename, &pBase, pRdonly);

  if( !rc ){
    initFile(pId, zFilename, pBase);
  }
  return rc;
}
static int crashOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
  OsFile *pBase = 0;



  int rc = origOs.xOpenExclusive(zFilename, &pBase, delFlag);

  if( !rc ){
    initFile(pId, zFilename, pBase);
  }
  return rc;
}
static int crashOpenReadOnly(const char *zFilename, OsFile **pId){
  OsFile *pBase = 0;



  int rc = origOs.xOpenReadOnly(zFilename, &pBase);

  if( !rc ){
    initFile(pId, zFilename, pBase);
  }
  return rc;
}

/*

  if( Tcl_GetIntFromObj(interp, objv[1], &delay) ) return TCL_ERROR;
  zFile = Tcl_GetStringFromObj(objv[2], &nFile);
  if( nFile>=sizeof(zCrashFile)-1 ){
    Tcl_AppendResult(interp, "crash file name too big", 0);
    return TCL_ERROR;
  }
  setCrashParams(delay, zFile);
  if( origOs.xOpenReadWrite==0 ){
    origOs = sqlite3Os;
    sqlite3Os.xOpenReadWrite = crashOpenReadWrite;
    sqlite3Os.xOpenExclusive = crashOpenExclusive;
    sqlite3Os.xOpenReadOnly = crashOpenReadOnly;
  }
  return TCL_OK;
}

/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
  return TCL_OK;
}

#endif /* SQLITE_TEST */

/*
** 2005 December 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 an example implementation of an asynchronous IO 
** backend for SQLite. It is used to test that the concept of asynchronous 
** IO in SQLite is valid.
*/

#include "sqliteInt.h"
#include "os.h"

#define MIN(x,y) ((x)<(y)?(x):(y))
#define MAX(x,y) ((x)>(y)?(x):(y))

typedef struct AsyncWrite AsyncWrite;
typedef struct AsyncFile AsyncFile;

/*
** TODO:
**     * File locks...
*/

/*
** THREAD SAFETY NOTES
**
** Basic rules:
**
**     * Both read and write access to the global write-op queue must be 
**       protected by the sqlite3Os mutex functions.
**     * The file handles from the underlying system are assumed not to 
**       be thread safe.
**     * See the last paragraph under "sqlite3_async_flush() Threads" for
**       an assumption to do with file-handle synchronization by the Os.
**
** File system operations (invoked by SQLite thread):
**
**     xOpenXXX (three versions)
**     xDelete
**     xFileExists
**
**     Todo:
**         xSyncDirectory
**
** File handle operations (invoked by SQLite thread):
**
**     The following operations add an entry to the global write-op list. They
**     prepare the entry, aquire the mutex momentarily while list pointers are 
**     manipulated to insert the new entry, and release the mutex.
**    
**         asyncWrite, asyncClose, asyncTruncate, asyncSync, 
**         asyncSetFullSync, asyncOpenDirectory.
**    
**     Read operations. Both of these read from both the underlying file and
**     the write-op list. So we grab the mutex for the whole call (even 
**     while performing a blocking read on the file).
**    
**         asyncRead, asyncFileSize.
**    
**     These locking primitives become no-ops. Files are always opened for 
**     exclusive access when using this IO backend:
**    
**         asyncLock, asyncUnlock, asyncLockState, asyncCheckReservedLock
**    
**     The sqlite3OsFileHandle() function is currently only used when 
**     debugging the pager module. Unless sqlite3OsClose() is called on the
**     file (shouldn't be possible for other reasons), the underlying 
**     implementations are safe to call without grabbing any mutex. So we just
**     go ahead and call it no matter what any other thread is doing.
**
**         asyncFileHandle.
**
**     Calling this method just manipulates the AsyncFile.iOffset variable. 
**     Since this variable is never accessed by an sqlite3_async_flush() thread,
**     this function does not require the mutex. Actual calls to OsSeek() take 
**     place just before OsWrite() or OsRead(), which are always protected by 
**     the mutex.
**    
**         asyncSeek.
**
** sqlite3_async_flush() (any thread):
**
**     A pseudo-mutex (a global boolean variable) is used to make sure only 
**     one thread is inside the sqlite3_async_flush() thread at any one time.
**     If the variable is set when a thread enters _flush(), then it 
**     immediately returns SQLITE_BUSY. Otherwise, it sets the variable, 
**     executes the body of the function, and clears the variable just before
**     returning. Both read and write access to said global variable 
**     (sqlite3_asyncIoBusy) is protected by sqlite3Os mutex, of course.
**
**     Inside sqlite3_async_flush() is a loop that works like this:
**
**         WHILE (write-op list is not empty)
**             Do IO operation at head of write-op list
**             Remove entry from head of write-op list
**         END WHILE
**
**     The mutex is always obtained during the <write-op list is not empty>
**     test, and when the entry is removed from the head of the write-op 
**     list. Sometimes it is held for the interim period (while the IO is
**     performed), and sometimes it is relinquished. It is relinquished if
**     (a) the IO op is an ASYNC_CLOSE or (b) when the file handle was 
**     opened, two of the underlying systems handles were opened on the
**     same file-system entry.
**
**     If condition (b) above is true, then one file-handle 
**     (AsyncFile.pBaseRead) is used exclusively by sqlite threads to read the
**     file, the other (AsyncFile.pBaseWrite) by sqlite3_async_flush() 
**     threads to perform write() operations. This means that read 
**     operations are not blocked by asynchronous writes (although 
**     asynchronous writes may still be blocked by reads).
**
**     This assumes that the OS keeps two handles open on the same file
**     properly in sync. That is, any read operation that starts after a
**     write operation on the same file system entry has completed returns
**     data consistent with the write. We also assume that if one thread 
**     reads a file while another is writing it all bytes other than the
**     ones actually being written contain valid data.
**
**     If the above assumptions are not true, set the preprocessor symbol
**     SQLITE_ASYNC_TWO_FILEHANDLES to 0.
*/

#ifndef SQLITE_ASYNC_TWO_FILEHANDLES
/* #define SQLITE_ASYNC_TWO_FILEHANDLES 0 */
#define SQLITE_ASYNC_TWO_FILEHANDLES 1
#endif

/* 
** First and last elements of the global write-op list. 
**
** Whenever an OsWrite(), OsSync(), OsTrunc() or OsClose() operation is
** requested, instead of performing the file IO immediately, a new AsyncWrite
** structure is allocated and added to the global linked list that starts at
** sqlite3_asyncListFirst. The next time to sqlite3_async_flush() is called,
** all operations are realised and the list elements deleted.
*/
static AsyncWrite *sqlite3_asyncListFirst = 0;
static AsyncWrite *sqlite3_asyncListLast = 0;

/* True after an IO error has occured */
/* static int *sqlite3_asyncIoError = 0; */

/* True if some thread is currently inside sqlite3_async_flush() */
static int sqlite3_asyncIoBusy = 0;

/* Possible values of AsyncWrite.op */
#define ASYNC_WRITE         1
#define ASYNC_SYNC          2
#define ASYNC_TRUNCATE      3
#define ASYNC_CLOSE         4
#define ASYNC_OPENDIRECTORY 5
#define ASYNC_SETFULLSYNC   6

#define ASYNC_DELETE        7
#define ASYNC_OPENEXCLUSIVE 8
#define ASYNC_SYNCDIRECTORY 9

/*
** The interpretation of the iOffset and nByte variables varies depending 
** on the value of AsyncWrite.op:
**
** ASYNC_WRITE:
**     iOffset -> Offset in file to write to.
**     nByte   -> Number of bytes of data to write (pointed to by zBuf).
**
** ASYNC_SYNC:
**     iOffset -> Unused.
**     nByte   -> Value of "fullsync" flag to pass to sqlite3OsSync().
**
** ASYNC_TRUNCATE:
**     iOffset -> Size to truncate file to.
**     nByte   -> Unused.
**
** ASYNC_CLOSE:
**     iOffset -> Unused.
**     nByte   -> Unused.
**
** ASYNC_OPENDIRECTORY:
**     iOffset -> Unused.
**     nByte   -> Number of bytes of zBuf points to (directory name).
**
** ASYNC_SETFULLSYNC:
**     iOffset -> Unused.
**     nByte   -> New value for the full-sync flag.
**
**
** ASYNC_DELETE:
**     iOffset -> Unused.
**     nByte   -> Number of bytes of zBuf points to (file name).
**
** ASYNC_OPENEXCLUSIVE:
**     iOffset -> Value of "delflag".
**     nByte   -> Number of bytes of zBuf points to (file name).
**
** For an ASYNC_WRITE operation, zBuf points to the data to write to the file. 
** This space is sqliteMalloc()d along with the AsyncWrite structure in a
** single blob, so is deleted when sqliteFree() is called on the parent 
** structure.
*/
struct AsyncWrite {
  AsyncFile *pFile;   /* File to write data to or sync */
  int op;             /* One of ASYNC_xxx etc. */
  i64 iOffset;        /* See above */
  int nByte;          /* See above */
  char *zBuf;         /* Data to write to file (or NULL if op!=ASYNC_WRITE) */
  AsyncWrite *pNext;  /* Next write operation (to any file) */
};

/* 
** The AsyncFile structure is a subclass of OsFile used for asynchronous IO.
*/
struct AsyncFile {
  IoMethod *pMethod;   /* Must be first */
  i64 iOffset;         /* Current seek() offset in file */
  OsFile *pBaseRead;   /* Read handle to the underlying Os file */
  OsFile *pBaseWrite;  /* Write handle to the underlying Os file */
};

/*
** Add an entry to the end of the global write-op list. pWrite should point 
** to an AsyncWrite structure allocated using sqliteMalloc(). A future call 
** to sqlite3_async_flush() is responsible for calling sqliteFree().
**
** Once an AsyncWrite structure has been added to the list, it must not be
** read or modified by the caller (in case another thread calls
** sqlite3_async_flush() ).
*/
static void addAsyncWrite(AsyncWrite *pWrite){
  sqlite3Os.xEnterMutex();
  assert( !pWrite->pNext );
  if( sqlite3_asyncListLast ){
    assert( sqlite3_asyncListFirst );
    sqlite3_asyncListLast->pNext = pWrite;
  }else{
    sqlite3_asyncListFirst = pWrite;
  }
  sqlite3_asyncListLast = pWrite;
  sqlite3Os.xLeaveMutex();
}

/*
** The caller should already hold the mutex when this is called.
*/
static void removeAsyncWrite(AsyncWrite *p){
  assert( p==sqlite3_asyncListFirst );
  assert( sqlite3_asyncListLast );
  if( sqlite3_asyncListFirst==sqlite3_asyncListLast ){
    assert( !sqlite3_asyncListFirst->pNext );
    sqlite3_asyncListLast = 0;
  }
  sqlite3_asyncListFirst = sqlite3_asyncListFirst->pNext;
}

/*
** This is a utility function to allocate and populate a new AsyncWrite
** structure and insert it (via addAsyncWrite() ) into the global list.
*/
static int addNewAsyncWrite(
  AsyncFile *pFile, 
  int op, 
  i64 iOffset, 
  int nByte,
  const char *zByte
){
  AsyncWrite *p = sqlite3Os.xMalloc(sizeof(AsyncWrite) + (zByte?nByte:0));
  if( !p ){
    return SQLITE_NOMEM;
  }
  p->op = op;
  p->iOffset = iOffset;
  p->nByte = nByte;
  p->pFile = pFile;
  p->pNext = 0;
  if( zByte ){
    p->zBuf = (char *)&p[1];
    memcpy(p->zBuf, zByte, nByte);
  }else{
    p->zBuf = 0;
  }
  addAsyncWrite(p);
  return SQLITE_OK;
}

/*
** Close the file. This just adds an entry to the write-op list, the file is
** not actually closed.
*/
static int asyncClose(OsFile **pId){
  return addNewAsyncWrite((AsyncFile *)*pId, ASYNC_CLOSE, 0, 0, 0);
}

/*
** Implementation of sqlite3OsWrite() for asynchronous files. Instead of 
** writing to the underlying file, this function adds an entry to the end of
** the global AsyncWrite list. Either SQLITE_OK or SQLITE_NOMEM may be
** returned.
*/
static int asyncWrite(OsFile *id, const void *pBuf, int amt){
  AsyncFile *pFile = (AsyncFile *)id;
  int rc = addNewAsyncWrite(pFile, ASYNC_WRITE, pFile->iOffset, amt, pBuf);
  pFile->iOffset += (i64)amt;
  return rc;
}

/*
** Truncate the file to nByte bytes in length. This just adds an entry to 
** the write-op list, no IO actually takes place.
*/
static int asyncTruncate(OsFile *id, i64 nByte){
  return addNewAsyncWrite((AsyncFile *)id, ASYNC_TRUNCATE, nByte, 0, 0);
}

/*
** Open the directory identified by zName and associate it with the 
** specified file. This just adds an entry to the write-op list, the 
** directory is opened later by sqlite3_async_flush().
*/
static int asyncOpenDirectory(OsFile *id, const char *zName){
  AsyncFile *pFile = (AsyncFile *)id;
  return addNewAsyncWrite(pFile, ASYNC_OPENDIRECTORY, 0, strlen(zName)+1,zName);
}

/*
** Sync the file. This just adds an entry to the write-op list, the 
** sync() is done later by sqlite3_async_flush().
*/
static int asyncSync(OsFile *id, int fullsync){
  return addNewAsyncWrite((AsyncFile *)id, ASYNC_SYNC, 0, fullsync, 0);
}

/*
** Set (or clear) the full-sync flag on the underlying file. This operation
** is queued and performed later by sqlite3_async_flush().
*/
static void asyncSetFullSync(OsFile *id, int value){
  addNewAsyncWrite((AsyncFile *)id, ASYNC_SETFULLSYNC, 0, value, 0);
}

/*
** Read data from the file. First we read from the filesystem, then adjust 
** the contents of the buffer based on ASYNC_WRITE operations in the 
** write-op queue. Todo: Do we need to think about ASYNC_TRUNCATE in 
** this method as well?
**
** This method holds the mutex from start to finish.
*/
static int asyncRead(OsFile *id, void *obuf, int amt){
  int rc = SQLITE_OK;
  i64 filesize;
  int nRead;
  AsyncFile *pFile = (AsyncFile *)id;

  /* Grab the mutex for the duration of the call */
  sqlite3Os.xEnterMutex();

  if( pFile->pBaseRead ){
    rc = sqlite3OsFileSize(pFile->pBaseRead, &filesize);
    if( rc!=SQLITE_OK ){
      goto asyncread_out;
    }
    rc = sqlite3OsSeek(pFile->pBaseRead, pFile->iOffset);
    if( rc!=SQLITE_OK ){
      goto asyncread_out;
    }
    nRead = MIN(filesize - pFile->iOffset, amt);
    if( nRead>0 ){
      rc = sqlite3OsRead(((AsyncFile *)id)->pBaseRead, obuf, nRead);
    }
  }

  if( rc==SQLITE_OK ){
    AsyncWrite *p;
    i64 iOffset = pFile->iOffset;           /* Current seek offset */

    for(p=sqlite3_asyncListFirst; p; p = p->pNext){
      if( p->pFile==pFile && p->op==ASYNC_WRITE ){
        int iBeginIn = (p->iOffset - iOffset);
        int iBeginOut = (iOffset - p->iOffset);
        int nCopy;

        if( iBeginIn<0 ) iBeginIn = 0;
        if( iBeginOut<0 ) iBeginOut = 0;
        nCopy = MIN(p->nByte-iBeginIn, amt-iBeginOut);

        if( nCopy>0 ){
          memcpy(&((char *)obuf)[iBeginOut], &p->zBuf[iBeginIn], nCopy);
        }
      }
    }

    pFile->iOffset += (i64)amt;
  }

asyncread_out:
  sqlite3Os.xLeaveMutex();
  return rc;
}

/*
** Seek to the specified offset. This just adjusts the AsyncFile.iOffset 
** variable - calling seek() on the underlying file is defered until the 
** next read() or write() operation. 
*/
static int asyncSeek(OsFile *id, i64 offset){
  AsyncFile *pFile = (AsyncFile *)id;
  pFile->iOffset = offset;
  return SQLITE_OK;
}

/*
** Read the size of the file. First we read the size of the file system 
** entry, then adjust for any ASYNC_WRITE or ASYNC_TRUNCATE operations 
** currently in the write-op list. 
**
** This method holds the mutex from start to finish.
*/
int asyncFileSize(OsFile *id, i64 *pSize){
  int rc = SQLITE_OK;
  i64 s = 0;
  OsFile *pBase;
  sqlite3Os.xEnterMutex();

  /* Read the filesystem size from the base file. If pBaseRead is NULL, this
  ** means the file hasn't been opened yet. In this case all relevant data 
  ** must be in the write-op queue anyway, so we can omit reading from the
  ** file-system.
  */
  pBase = ((AsyncFile *)id)->pBaseRead;
  if( pBase ){
    rc = sqlite3OsFileSize(pBase, &s);
  }

  if( rc==SQLITE_OK ){
    AsyncWrite *p;
    for(p=sqlite3_asyncListFirst; p; p = p->pNext){
      if( p->pFile==(AsyncFile *)id ){
        switch( p->op ){
          case ASYNC_WRITE:
            s = MAX(p->iOffset + (i64)(p->nByte), s);
            break;
          case ASYNC_TRUNCATE:
            s = MIN(s, p->nByte);
            break;
        }
      }
    }
    *pSize = s;
  }
  sqlite3Os.xLeaveMutex();
  return rc;
}

/*
** Return the operating system file handle. This is only used for debugging 
** at the moment anyway.
*/
static int asyncFileHandle(OsFile *id){
  return sqlite3OsFileHandle(((AsyncFile *)id)->pBaseRead);
}

static int asyncLock(OsFile *id, int lockType){
  return SQLITE_OK;
}
static int asyncUnlock(OsFile *id, int lockType){
  return SQLITE_OK;
}

/*
** This function is called when the pager layer first opens a database file
** and is checking for a hot-journal.
*/
static int asyncCheckReservedLock(OsFile *id){
  return SQLITE_OK;
}

/* 
** This is broken. But sqlite3OsLockState() is only used for testing anyway.
*/
static int asyncLockState(OsFile *id){
  return SQLITE_OK;
}

/*
** The three file-open functions for the underlying file system layer.
*/
static int (*xOrigOpenReadWrite)(const char*, OsFile**, int*) = 0;
static int (*xOrigOpenExclusive)(const char*, OsFile**, int) = 0;
static int (*xOrigOpenReadOnly)(const char*, OsFile**) = 0;

/*
** Pointers to the original versions of other overridden file-system 
** operations.
*/
static int (*xOrigDelete)(const char*) = 0;
static int (*xOrigFileExists)(const char*) = 0;
static int (*xOrigSyncDirectory)(const char*) = 0;

static int asyncOpenFile(
  const char *zName, 
  OsFile **pFile, 
  OsFile *pBaseRead,
  int openSecondFile
){
  int rc;
  AsyncFile *p;
  OsFile *pBaseWrite = 0;

  static IoMethod iomethod = {
    asyncClose,
    asyncOpenDirectory,
    asyncRead,
    asyncWrite,
    asyncSeek,
    asyncTruncate,
    asyncSync,
    asyncSetFullSync,
    asyncFileHandle,
    asyncFileSize,
    asyncLock,
    asyncUnlock,
    asyncLockState,
    asyncCheckReservedLock
  };

  if( openSecondFile && SQLITE_ASYNC_TWO_FILEHANDLES ){
    int dummy;
    rc = xOrigOpenReadWrite(zName, &pBaseWrite, &dummy);
    if( rc!=SQLITE_OK ){
      goto error_out;
    }
  }

  p = (AsyncFile *)sqlite3Os.xMalloc(sizeof(AsyncFile));
  if( !p ){
    rc = SQLITE_NOMEM;
    goto error_out;
  }
  memset(p, 0, sizeof(AsyncFile));
  
  p->pMethod = &iomethod;
  p->pBaseRead = pBaseRead;
  p->pBaseWrite = pBaseWrite;
  
  *pFile = (OsFile *)p;
  return SQLITE_OK;

error_out:
  assert(!p);
  sqlite3OsClose(&pBaseRead);
  sqlite3OsClose(&pBaseWrite);
  *pFile = 0;
  return rc;
}

/*
** The async-IO backends implementation of the three functions used to open
** a file (xOpenExclusive, xOpenReadWrite and xOpenReadOnly). Most of the 
** work is done in function asyncOpenFile() - see above.
*/
static int asyncOpenExclusive(const char *z, OsFile **ppFile, int delFlag){
  int rc = asyncOpenFile(z, ppFile, 0, 0);
  if( rc==SQLITE_OK ){
    AsyncFile *pFile = (AsyncFile *)(*ppFile);
    int nByte = strlen(z)+1;
    i64 i = (i64)(delFlag);
    rc = addNewAsyncWrite(pFile, ASYNC_OPENEXCLUSIVE, i, nByte, z);
    if( rc!=SQLITE_OK ){
      sqlite3Os.xFree(pFile);
      *ppFile = 0;
    }
  }
  return rc;
}
static int asyncOpenReadOnly(const char *z, OsFile **ppFile){
  OsFile *pBase = 0;
  int rc = xOrigOpenReadOnly(z, &pBase);
  if( rc==SQLITE_OK ){
    rc = asyncOpenFile(z, ppFile, pBase, 0);
  }
  return rc;
}
static int asyncOpenReadWrite(const char *z, OsFile **ppFile, int *pReadOnly){
  OsFile *pBase = 0;
  int rc = xOrigOpenReadWrite(z, &pBase, pReadOnly);
  if( rc==SQLITE_OK ){
    rc = asyncOpenFile(z, ppFile, pBase, (*pReadOnly ? 0 : 1));
  }
  return rc;
}

/*
** Implementation of sqlite3Os.xDelete. Add an entry to the end of the 
** write-op queue to perform the delete.
*/
static int asyncDelete(const char *z){
  return addNewAsyncWrite(0, ASYNC_DELETE, 0, strlen(z)+1, z);
}

/*
** Implementation of sqlite3Os.xDelete. Add an entry to the end of the 
** write-op queue to perform the delete.
*/
static int asyncSyncDirectory(const char *z){
  return addNewAsyncWrite(0, ASYNC_SYNCDIRECTORY, 0, strlen(z)+1, z);
}

/*
** Implementation of sqlite3Os.xFileExists. Return true if file 'z' exists
** in the file system. 
**
** This method holds the mutex from start to finish.
*/
static int asyncFileExists(const char *z){
  int ret;
  AsyncWrite *p;
  sqlite3Os.xEnterMutex();

  /* See if the real file system contains the specified file.  */
  ret = xOrigFileExists(z);
  
  for(p=sqlite3_asyncListFirst; p; p = p->pNext){
    if( p->op==ASYNC_DELETE && 0==strcmp(p->zBuf, z) ){
      ret = 0;
    }else if( p->op==ASYNC_OPENEXCLUSIVE && 0==strcmp(p->zBuf, z) ){
      ret = 1;
    }
  }

  sqlite3Os.xLeaveMutex();
  return ret;
}

/*
** The following routine is one of two exported symbols in this module (along
** with sqlite3_async_flush(), see below). This routine should be called
** once to enable the asynchronous IO features implemented in this file. If 
** the features are successfully enabled (or if they have already been 
** enabled) then SQLITE_OK is returned. Otherwise, SQLITE_MISUSE.
*/
int sqlite3_async_enable(void){
  if( xOrigOpenReadWrite==0 ){
    xOrigOpenReadWrite = sqlite3Os.xOpenReadWrite;
    xOrigOpenReadOnly = sqlite3Os.xOpenReadOnly;
    xOrigOpenExclusive = sqlite3Os.xOpenExclusive;
    xOrigDelete = sqlite3Os.xDelete;
    xOrigFileExists = sqlite3Os.xFileExists;
    xOrigSyncDirectory = sqlite3Os.xSyncDirectory;

    sqlite3Os.xOpenReadWrite = asyncOpenReadWrite;
    sqlite3Os.xOpenReadOnly = asyncOpenReadOnly;
    sqlite3Os.xOpenExclusive = asyncOpenExclusive;
    sqlite3Os.xDelete = asyncDelete;
    sqlite3Os.xFileExists = asyncFileExists;
    sqlite3Os.xSyncDirectory = asyncSyncDirectory;
  }
  return SQLITE_OK;
}

/* 
** This function is called externally to perform queued write and sync
** operations. It returns when an IO error occurs or there are no more queued
** operations to perform.
*/
int sqlite3_async_flush(void){
  AsyncWrite *p = 0;
  int rc = SQLITE_OK;

  /* Grab the mutex and set the sqlite3_asyncIoBusy flag to make sure this
  ** is the only thread performing an sqlite3_async_flush() at this time.
  ** Or, if some other thread is already inside this function, return 
  ** SQLITE_BUSY to the caller.
  */
  sqlite3Os.xEnterMutex();
  if( sqlite3_asyncIoBusy ){
    sqlite3Os.xLeaveMutex();
    return SQLITE_BUSY;
  }
  sqlite3_asyncIoBusy = 1;

  while( (p = sqlite3_asyncListFirst) && rc==SQLITE_OK ){
    int isInsideMutex = 1;

    /* Right now this thread is holding the global mutex. Variable 'p' points
    ** to the first entry in the write-op queue. In the general case, we
    ** hold on to the mutex for the entire body of the loop. 
    **
    ** However in the cases enumerated below, we relinquish the mutex,
    ** perform the IO, and then re-request the mutex before removing 'p' from
    ** the head of the write-op queue. The idea is to increase concurrency with
    ** sqlite threads.
    **
    **     * An ASYNC_CLOSE operation.
    **     * An ASYNC_OPENEXCLUSIVE operation. For this one, we relinquish 
    **       the mutex, call the underlying xOpenExclusive() function, then
    **       re-aquire the mutex before seting the AsyncFile.pBaseRead 
    **       variable.
    **     * ASYNC_SYNC and ASYNC_WRITE operations, if 
    **       SQLITE_ASYNC_TWO_FILEHANDLES was set at compile time and two
    **       file-handles are open for the particular file being "synced".
    */
    OsFile *pBase = 0;
    if( p->pFile ){
      pBase = p->pFile->pBaseWrite;
      if( 
        p->op==ASYNC_CLOSE || 
        p->op==ASYNC_OPENEXCLUSIVE ||
        (pBase && (p->op==ASYNC_SYNC || p->op==ASYNC_WRITE) ) 
      ){
        sqlite3Os.xLeaveMutex();
        isInsideMutex = 0;
      }
      if( !pBase ){
        pBase = p->pFile->pBaseRead;
      }
    }

    switch( p->op ){
      case ASYNC_WRITE:
        assert( pBase );
        rc = sqlite3OsSeek(pBase, p->iOffset);
        if( rc==SQLITE_OK ){
          rc = sqlite3OsWrite(pBase, (const void *)(p->zBuf), p->nByte);
        }
        break;

      case ASYNC_SYNC:
        assert( pBase );
        rc = sqlite3OsSync(pBase, p->nByte);
        break;

      case ASYNC_TRUNCATE:
        assert( pBase );
        rc = sqlite3OsTruncate(pBase, p->nByte);
        break;

      case ASYNC_CLOSE:
        sqlite3OsClose(&p->pFile->pBaseRead);
        sqlite3OsClose(&p->pFile->pBaseWrite);
        sqlite3Os.xFree(p->pFile);
        break;

      case ASYNC_OPENDIRECTORY:
        assert( pBase );
        sqlite3OsOpenDirectory(pBase, p->zBuf);
        break;

      case ASYNC_SETFULLSYNC:
        assert( pBase );
        sqlite3OsSetFullSync(pBase, p->nByte);
        break;

      case ASYNC_DELETE:
        rc = xOrigDelete(p->zBuf);
        break;

      case ASYNC_SYNCDIRECTORY:
        rc = xOrigSyncDirectory(p->zBuf);
        break;

      case ASYNC_OPENEXCLUSIVE: {
        AsyncFile *pFile = p->pFile;
        int delFlag = ((p->iOffset)?1:0);
        OsFile *pBase = 0;
        rc = xOrigOpenExclusive(p->zBuf, &pBase, delFlag);

        sqlite3Os.xEnterMutex();
        isInsideMutex = 1;
        if( rc==SQLITE_OK ){
          pFile->pBaseRead = pBase;
        }
        break;
      }

      default: assert(!"Illegal value for AsyncWrite.op");
    }

    /* If we didn't hang on to the mutex during the IO op, obtain it now
    ** so that the AsyncWrite structure can be safely removed from the 
    ** global write-op queue.
    */
    if( !isInsideMutex ){
      sqlite3Os.xEnterMutex();
    }
    if( rc==SQLITE_OK ){
      removeAsyncWrite(p);
      sqlite3Os.xFree(p);
    }
  }

  /* Clear the io-busy flag and exit the mutex */
  assert( sqlite3_asyncIoBusy );
  sqlite3_asyncIoBusy = 0;
  sqlite3Os.xLeaveMutex();

  return rc;
}

/*
** The following code defines a Tcl interface for testing the asynchronous 
** IO implementation in this file.
*/
#if defined(SQLITE_TEST) && defined(TCLSH)

#include <tcl.h>

/*
** sqlite3_async_enable
*/
static int testAsyncEnable(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  if( sqlite3_async_enable() ){
    Tcl_SetResult(interp, "sqlite3_async_enable() failed", TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** This is the main proc for a thread spawned by the Tcl command 
** [sqlite3_async_flush -start]. The client data is a pointer to an integer
** variable that will be set to non-zero when this thread should exit.
*/
static void testAsyncFlushThread(ClientData clientData){
  int *pStop = (int *)clientData;
  int rc = 0;

  /* Run in a loop until an IO error occurs or we are told to stop via 
  ** the *pStop variable. Each iteration of the loop, call 
  ** sqlite3_async_flush() and then sleep for a tenth of a second.
  */
  while( !(*pStop) && !rc ){
    rc = sqlite3_async_flush();
    assert( rc==SQLITE_OK );
    Tcl_Sleep(100);
  }
  if( rc==0 ){
    rc = sqlite3_async_flush();
  }
  Tcl_ExitThread(rc);
}

/*
** sqlite3_async_flush
** sqlite3_async_flush -start
** sqlite3_async_flush -stop
*/
static int testAsyncFlush(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  static Tcl_ThreadId thread_id = 0;
  static int stop = 0;

  assert(stop==0);

  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?-start | -stop?");
    return TCL_ERROR;
  }

  if( objc==2 ){
    char *zOpt = Tcl_GetString(objv[1]);
    if( 0==strcmp(zOpt, "-start") ){
      /* Unless it is already running, kick off the _flush() thread */
      if( thread_id ){
        Tcl_AppendResult(interp, "Thread has already started", 0);
        return TCL_ERROR;
      }else{
        int rc = Tcl_CreateThread(
          &thread_id, 
          testAsyncFlushThread, 
          &stop, 
          TCL_THREAD_STACK_DEFAULT, 
          TCL_THREAD_JOINABLE
        );
        if( rc!=TCL_OK ){
          Tcl_AppendResult(interp, "Tcl_CreateThread() failed", 0);
          return TCL_ERROR;
        }
      }
    }else if( 0==strcmp(zOpt, "-stop") ){
      int dummy;
      stop = 1;
      Tcl_JoinThread(thread_id, &dummy);
      stop = 0;
      thread_id = 0;
    }else{
      Tcl_AppendResult(interp, "Invalid option: \"", zOpt, "\"", 0);
      return TCL_ERROR;
    }
  }else if( sqlite3_async_flush() ){
    Tcl_SetResult(interp, "sqlite3_async_flush() failed", TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

int Sqlitetestasync_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp,"sqlite3_async_enable",testAsyncEnable,0,0);
  Tcl_CreateObjCommand(interp,"sqlite3_async_flush",testAsyncFlush,0,0);
  return TCL_OK;
}

#endif

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.160 2006/01/06 06:33:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*

** The function sqlite3FreeX performs the same task as sqlite3Free and is
** guaranteed to be a real function. The same holds for sqlite3MallocX
**
** The above APIs are implemented in terms of the functions provided at the Os
** level (not in this file). The Os level interface is never accessed directly
** by code outside of this file.
**
**     sqlite3Os.xMalloc()
**     sqlite3Os.xRealloc()
**     sqlite3Os.xFree()
**     sqlite3Os.xAllocationSize()
**
** Functions sqlite3MallocRaw() and sqlite3Realloc() may invoke 
** sqlite3_release_memory() if a call to sqlite3Os.xMalloc() or
** sqlite3Os.xRealloc() fails (or if the soft-heap-limit for the thread is
** exceeded). Function sqlite3Malloc() usually invokes
** sqlite3MallocRaw().
**
** MALLOC TEST WRAPPER ARCHITECTURE
**
** The test wrapper provides extra test facilities to ensure the library 
** does not leak memory and handles the failure of the underlying (Os level)

*/ 

#define TESTALLOC_OFFSET_GUARD1(p)    (sizeof(void *) * 2)
#define TESTALLOC_OFFSET_DATA(p) ( \
  TESTALLOC_OFFSET_GUARD1(p) + sizeof(u32) * TESTALLOC_NGUARD \
)
#define TESTALLOC_OFFSET_GUARD2(p) ( \
  TESTALLOC_OFFSET_DATA(p) + sqlite3Os.xAllocationSize(p) - TESTALLOC_OVERHEAD \
)
#define TESTALLOC_OFFSET_LINENUMBER(p) ( \
  TESTALLOC_OFFSET_GUARD2(p) + sizeof(u32) * TESTALLOC_NGUARD \
)
#define TESTALLOC_OFFSET_FILENAME(p) ( \
  TESTALLOC_OFFSET_LINENUMBER(p) + sizeof(u32) \
)

      return 1;
    }
  }
  return 0;
}

/*
** The argument is a pointer returned by sqlite3Os.xMalloc() or xRealloc().
** assert() that the first and last (TESTALLOC_NGUARD*4) bytes are set to the
** values set by the applyGuards() function.
*/
static void checkGuards(u32 *p)
{
  int i;
  char *zAlloc = (char *)p;

    u32 guard = 0;
    memcpy(&guard, &z[i*sizeof(u32)], sizeof(u32));
    assert(guard==0xdead3344);
  }
}

/*
** The argument is a pointer returned by sqlite3Os.xMalloc() or Realloc(). The
** first and last (TESTALLOC_NGUARD*4) bytes are set to known values for use as 
** guard-posts.
*/
static void applyGuards(u32 *p)
{
  int i;
  char *z;

  Tcl_IncrRefCount(pRes);

  for(p=pTsd->pFirst; p; p=((void **)p)[1]){
    Tcl_Obj *pEntry = Tcl_NewObj();
    Tcl_Obj *pStack = Tcl_NewObj();
    char *z;
    u32 iLine;
    int nBytes = sqlite3Os.xAllocationSize(p) - TESTALLOC_OVERHEAD;
    char *zAlloc = (char *)p;
    int i;

    Tcl_ListObjAppendElement(0, pEntry, Tcl_NewIntObj(nBytes));

    z = &zAlloc[TESTALLOC_OFFSET_FILENAME(p)];
    Tcl_ListObjAppendElement(0, pEntry, Tcl_NewStringObj(z, -1));

  Tcl_SetObjResult(interp, pRes);
  Tcl_DecrRefCount(pRes);
  return TCL_OK;
}
#endif

/*
** This is the test layer's wrapper around sqlite3Os.xMalloc().
*/
static void * OSMALLOC(int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  SqliteTsd *pTsd = sqlite3Tsd();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p;
    p = (u32 *)sqlite3Os.xMalloc(n + TESTALLOC_OVERHEAD);
    assert(p);
    sqlite3_nMalloc++;
    applyGuards(p);
    linkAlloc(p);
    return (void *)(&p[TESTALLOC_NGUARD + 2*sizeof(void *)/sizeof(u32)]);
  }
  return 0;
}

/*
** This is the test layer's wrapper around sqlite3Os.xFree(). The argument is a
** pointer to the space allocated for the application to use.
*/
void OSFREE(void *pFree){
  u32 *p = (u32 *)getOsPointer(pFree);   /* p points to Os level allocation */
  checkGuards(p);
  unlinkAlloc(p);
  sqlite3Os.xFree(p);
  sqlite3_nFree++;
}

/*
** This is the test layer's wrapper around sqlite3Os.xRealloc().
*/
void * OSREALLOC(void *pRealloc, int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  SqliteTsd *pTsd = sqlite3Tsd();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p = (u32 *)getOsPointer(pRealloc);
    checkGuards(p);
    p = sqlite3Os.xRealloc(p, n + TESTALLOC_OVERHEAD);
    applyGuards(p);
    relinkAlloc(p);
    return (void *)(&p[TESTALLOC_NGUARD + 2*sizeof(void *)/sizeof(u32)]);
  }
  return 0;
}

void OSMALLOC_FAILED(){
  sqlite3Tsd()->isFail = 0;
}

int OSSIZEOF(void *p){
  if( p ){
    u32 *pOs = (u32 *)getOsPointer(p);
    return sqlite3Os.xAllocationSize(pOs) - TESTALLOC_OVERHEAD;
  }
  return 0;
}

#else
/* Define macros to call the sqlite3Os.xXXX interface directly if 
** the SQLITE_MEMDEBUG macro is not defined.
*/
#define OSMALLOC(x)        sqlite3Os.xMalloc(x)
#define OSREALLOC(x,y)     sqlite3Os.xRealloc(x,y)
#define OSFREE(x)          sqlite3Os.xFree(x)
#define OSSIZEOF(x)        sqlite3Os.xAllocationSize(x)
#define OSMALLOC_FAILED()

#endif
/*
** End code for memory allocation system test layer.
**--------------------------------------------------------------------------*/

/*
** The handleSoftLimit() function is called before each call to 
** sqlite3Os.xMalloc() or xRealloc(). The parameter 'n' is the number of
** extra bytes about to be allocated (for Realloc() this means the size of the
** new allocation less the size of the old allocation). If the extra allocation
** means that the total memory allocated to SQLite in this thread would exceed
** the limit set by sqlite3_soft_heap_limit(), then sqlite3_release_memory() is
** called to try to avoid this. No indication of whether or not this is
** successful is returned to the caller.
**

}
#else
#define handleSoftLimit()
#endif

/*
** Allocate and return N bytes of uninitialised memory by calling
** sqlite3Os.xMalloc(). If the Malloc() call fails, attempt to free memory 
** by calling sqlite3_release_memory().
*/
void *sqlite3MallocRaw(int n){
  SqliteTsd *pTsd = sqlite3Tsd();
  void *p = 0;
  if( n>0 && !pTsd->mallocFailed ){
    handleSoftLimit(n);

      OSMALLOC_FAILED();
    }
  }
  return p;
}

/*
** Resize the allocation at p to n bytes by calling sqlite3Os.xRealloc(). The
** pointer to the new allocation is returned.  If the Realloc() call fails,
** attempt to free memory by calling sqlite3_release_memory().
*/
void *sqlite3Realloc(void *p, int n){
  SqliteTsd *pTsd = sqlite3Tsd();
  if( pTsd->mallocFailed ){
    return 0;

}
#endif

/*
** Return a pointer to the SqliteTsd associated with the calling thread.
*/
SqliteTsd *sqlite3Tsd(){
  SqliteTsd *pTsd = sqlite3Os.xThreadSpecificData(sizeof(SqliteTsd));
  if( pTsd && !pTsd->isInit ){
    pTsd->nSoftHeapLimit = -1;
#ifndef NDEBUG
    pTsd->mallocAllowed = 1;
#endif
    pTsd->isInit = 1;
  }

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.53 2005/12/09 20:02:06 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"
#include "os.h"

#ifndef SQLITE_OMIT_VACUUM
/*

  ** run more than once or twice is vanishingly small.  We are certain
  ** enough that this loop will always terminate (and terminate quickly)
  ** that we don't even bother to set a maximum loop count.
  */
  do {
    zTemp[nFilename] = '-';
    randomName((unsigned char*)&zTemp[nFilename+1]);
  } while( sqlite3Os.xFileExists(zTemp) );

  /* Before we even attach it, compile a DETACH statement for vacuum_db. This
  ** way, if malloc() fails we can detach the database without needing to
  ** dynamically allocate memory.
  */ 
  rc = sqlite3_prepare(db, "DETACH vacuum_db", -1, &pDetach, 0);
  if( rc!=SQLITE_OK ){

  ** Fix this so the flag and return code match.
  */
  if( rc==SQLITE_NOMEM ){
    sqlite3Tsd()->mallocFailed = 1;
  }

  if( zTemp ){
    sqlite3Os.xDelete(zTemp);
    sqliteFree(zTemp);
  }
  sqliteFree( zSql );
  sqlite3ResetInternalSchema(db, 0);
#endif

  return rc;
}

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.512 2006/01/05 23:42:51 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

    if( p->trace ){
      if( pc==0 ){
        printf("VDBE Execution Trace:\n");
        sqlite3VdbePrintSql(p);
      }
      sqlite3VdbePrintOp(p->trace, pc, pOp);
    }
    if( p->trace==0 && pc==0 && sqlite3Os.xFileExists("vdbe_sqltrace") ){
      sqlite3VdbePrintSql(p);
    }
#endif
      

    /* Check to see if we need to simulate an interrupt.  This only happens
    ** if we have a special test build.

      if( sqlite3SafetyOn(db) ){
        p->rc = SQLITE_MISUSE;
        return SQLITE_MISUSE;
      }
    }
    if( db->xProfile && !db->init.busy ){
      double rNow;
      sqlite3Os.xCurrentTime(&rNow);
      p->startTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0;
    }
#endif

    /* Print a copy of SQL as it is executed if the SQL_TRACE pragma is turned
    ** on in debugging mode.
    */

#ifndef SQLITE_OMIT_TRACE
  /* Invoke the profile callback if there is one
  */
  if( rc!=SQLITE_ROW && db->xProfile && !db->init.busy ){
    double rNow;
    u64 elapseTime;

    sqlite3Os.xCurrentTime(&rNow);
    elapseTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0 - p->startTime;
    assert( p->nOp>0 );
    assert( p->aOp[p->nOp-1].opcode==OP_Noop );
    assert( p->aOp[p->nOp-1].p3!=0 );
    assert( p->aOp[p->nOp-1].p3type==P3_DYNAMIC );
    db->xProfile(db->pProfileArg, p->aOp[p->nOp-1].p3, elapseTime);
  }

  p->aLabel = 0;

  *pMaxFuncArgs = nMaxArgs;
  *pMaxStack = nMaxStack;

  /* If we never rollback a statement transaction, then statement
  ** transactions are not needed.  So change every OP_Statement
  ** opcode into an OP_Noop.  This avoid a call to sqlite3Os.xOpenExclusive()
  ** which can be expensive on some platforms.
  */
  if( hasStatementBegin && !doesStatementRollback ){
    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
      if( pOp->opcode==OP_Statement ){
        pOp->opcode = OP_Noop;
      }

  }
  for(n=0; n<p->nMem; n++){
    p->aMem[n].flags = MEM_Null;
  }

#ifdef SQLITE_DEBUG
  if( (p->db->flags & SQLITE_VdbeListing)!=0
    || sqlite3Os.xFileExists("vdbe_explain")
  ){
    int i;
    printf("VDBE Program Listing:\n");
    sqlite3VdbePrintSql(p);
    for(i=0; i<p->nOp; i++){
      sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
    }
  }
  if( sqlite3Os.xFileExists("vdbe_trace") ){
    p->trace = stdout;
  }
#endif
  p->pTos = &p->aStack[-1];
  p->pc = -1;
  p->rc = SQLITE_OK;
  p->uniqueCnt = 0;

      u32 random;
      sqliteFree(zMaster);
      sqlite3Randomness(sizeof(random), &random);
      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
      if( !zMaster ){
        return SQLITE_NOMEM;
      }
    }while( sqlite3Os.xFileExists(zMaster) );

    /* Open the master journal. */
    rc = sqlite3Os.xOpenExclusive(zMaster, &master, 0);
    if( rc!=SQLITE_OK ){
      sqliteFree(zMaster);
      return rc;
    }
 
    /* Write the name of each database file in the transaction into the new
    ** master journal file. If an error occurs at this point close

        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
        if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
          needSync = 1;
        }
        rc = sqlite3OsWrite(master, zFile, strlen(zFile)+1);
        if( rc!=SQLITE_OK ){
          sqlite3OsClose(&master);
          sqlite3Os.xDelete(zMaster);
          sqliteFree(zMaster);
          return rc;
        }
      }
    }


    /* Sync the master journal file. Before doing this, open the directory
    ** the master journal file is store in so that it gets synced too.
    */
    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
    rc = sqlite3OsOpenDirectory(master, zMainFile);
    if( rc!=SQLITE_OK ||
          (needSync && (rc=sqlite3OsSync(master,0))!=SQLITE_OK) ){
      sqlite3OsClose(&master);
      sqlite3Os.xDelete(zMaster);
      sqliteFree(zMaster);
      return rc;
    }

    /* Sync all the db files involved in the transaction. The same call
    ** sets the master journal pointer in each individual journal. If
    ** an error occurs here, do not delete the master journal file.

    }
    sqlite3OsClose(&master);

    /* Delete the master journal file. This commits the transaction. After
    ** doing this the directory is synced again before any individual
    ** transaction files are deleted.
    */
    rc = sqlite3Os.xDelete(zMaster);
    assert( rc==SQLITE_OK );
    sqliteFree(zMaster);
    zMaster = 0;
    rc = sqlite3Os.xSyncDirectory(zMainFile);
    if( rc!=SQLITE_OK ){
      /* This is not good. The master journal file has been deleted, but
      ** the directory sync failed. There is no completely safe course of
      ** action from here. The individual journals contain the name of the
      ** master journal file, but there is no way of knowing if that
      ** master journal exists now or if it will exist after the operating
      ** system crash that may follow the fsync() failure.

#
#    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 runs all tests.
#
# $Id: async.test,v 1.1 2006/01/03 13:39:26 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
rename finish_test really_finish_test
proc finish_test {} {}
set ISQUICK 1

if {[info exists ::tcl_platform(threaded)]} {
  set USE_THREAD 1
} else {
  set USE_THREAD 0
}

set INCLUDE {
  select1.test
  select2.test
  select3.test
  select4.test
  insert.test
  insert2.test
  insert3.test
}
#set INCLUDE [lrange $INCLUDE 0 0]

# Enable asynchronous IO.
sqlite3_async_enable

# set USE_THREAD 0
if {$USE_THREAD} {
  sqlite3_async_flush -start
} else {
  rename do_test really_do_test
  proc do_test {name args} {
    uplevel really_do_test async_io-$name $args
    sqlite3_async_flush
  }
}

foreach testfile [lsort -dictionary [glob $testdir/*.test]] {
  set tail [file tail $testfile]
  if {[lsearch -exact $INCLUDE $tail]<0} continue
  source $testfile
  catch {db close}
#  if {$sqlite_open_file_count>0} {
#    puts "$tail did not close all files: $sqlite_open_file_count"
#    incr nErr
#    lappend ::failList $tail
#  }
}
#source $testdir/misuse.test


if {$USE_THREAD} {
  sqlite3_async_flush -stop
} else {
  rename do_test {}
  rename really_do_test do_test
  puts "Warning: Tcl library was without --enable-threads."
  puts "         Cannot test async IO properly."
  sqlite3_async_flush
}

set sqlite_open_file_count 0
really_finish_test

# The focus of this file is testing the ability of the database to
# uses its rollback journal to recover intact (no database corruption)
# from a power failure during the middle of a COMMIT.  The OS interface
# modules are overloaded in a separate instance of testfixture using
# the modified I/O routines found in test6.c.  These routines allow us
# to simulate the kind of file damage that occurs after a power failure.
#
# $Id: crash.test,v 1.20 2005/11/26 00:25:04 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl






# set repeats 100
set repeats 10

# This proc execs a seperate process that crashes midway through executing
# the SQL script $sql on database test.db.
#

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: ioerr.test,v 1.21 2005/08/20 13:47:42 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl


# If SQLITE_DEFAULT_AUTOVACUUM is set to true, then a simulated IO error
# on the 8th IO operation in the SQL script below doesn't report an error.

  CREATE TABLE t1(a,b,c);
  CREATE TABLE test2.t2(a,b,c);
  COMMIT;
} -exclude $ex

# Test IO errors when replaying two hot journals from a 2-file 
# transaction. This test only runs on UNIX.
if {$tcl_platform(platform)=="unix" && [file exists ./crashtest]
     && ![catch {sqlite3 -has-codec} r] && !$r} {
  do_ioerr_test ioerr-6 -tclprep {
    execsql {
      ATTACH 'test2.db' as aux;
      CREATE TABLE tx(a, b);
      CREATE TABLE aux.ty(a, b);
    }
    set rc [crashsql 2 test2.db-journal {
      ATTACH 'test2.db' as aux;
      PRAGMA cache_size = 10;
      BEGIN;
      CREATE TABLE aux.t2(a, b, c);
      CREATE TABLE t1(a, b, c);
      COMMIT;
    }]
    if {$rc!="1 {child process exited abnormally}"} {
      error "Wrong error message: $rc"
    }
  } -sqlbody {
    SELECT * FROM sqlite_master;
    SELECT * FROM aux.sqlite_master;

  }
} 

# Test handling of IO errors that occur while rolling back hot journal
# files.
#
# These tests can't be run on windows because the windows version of 

#***********************************************************************
# This file attempts to check the library in an out-of-memory situation.
# When compiled with -DSQLITE_DEBUG=1, the SQLite library accepts a special
# command (sqlite_malloc_fail N) which causes the N-th malloc to fail.  This
# special feature is used to see what happens in the library if a malloc
# were to really fail due to an out-of-memory situation.
#
# $Id: malloc.test,v 1.25 2005/12/06 12:53:01 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Only run these tests if memory debugging is turned on.
#
if {[info command sqlite_malloc_stat]==""} {

  set sql16 [encoding convertto unicode "SELECT * FROM sqlite_master"]
  append sql16 "\00\00"
  set ::STMT [sqlite3_prepare16 $::DB $sql16 -1 DUMMY]
  sqlite3_finalize $::STMT
} 

# Test malloc errors when replaying two hot journals from a 2-file 
# transaction. This test only runs on UNIX.
if {$tcl_platform(platform)=="unix"} {
  do_malloc_test 13 -tclprep {
    set rc [crashsql 1 test2.db {
      ATTACH 'test2.db' as aux;
      PRAGMA cache_size = 10;
      BEGIN;
      CREATE TABLE aux.t2(a, b, c);
      CREATE TABLE t1(a, b, c);