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Overview
Comment:Break out DBBE drivers into separate files. (CVS 157)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:979ef5d5d64b8e38cc15fef0d2d507ca2fe6842c
User & Date: drh 2000-10-19 01:49:02
Context
2000-10-19
02:00
Version 1.0.13 (CVS 490) check-in: b9c84fa5 user: drh tags: trunk
01:49
Break out DBBE drivers into separate files. (CVS 157) check-in: 979ef5d5 user: drh tags: trunk
2000-10-17
01:35
Version 1.0.12 (CVS 491) check-in: 7330218a user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to Makefile.in.

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# The library that programs using readline() must link against.
#
LIBREADLINE = @TARGET_READLINE_LIBS@

# Object files for the SQLite library.
#
LIBOBJ = build.o dbbe.o delete.o expr.o insert.o \
         main.o parse.o printf.o select.o table.o tokenize.o update.o \
         util.o vdbe.o where.o tclsqlite.o

# All of the source code files.
#
SRC = \
  $(TOP)/src/build.c \
  $(TOP)/src/dbbe.c \

  $(TOP)/src/dbbe.h \
  $(TOP)/src/dbbemem.c \
  $(TOP)/src/delete.c \
  $(TOP)/src/expr.c \
  $(TOP)/src/insert.c \
  $(TOP)/src/main.c \
  $(TOP)/src/parse.y \
................................................................................

build.o:	$(TOP)/src/build.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/build.c

dbbe.o:	$(TOP)/src/dbbe.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/dbbe.c




main.o:	$(TOP)/src/main.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/main.c

parse.o:	parse.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c parse.c

parse.h:	parse.c







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# The library that programs using readline() must link against.
#
LIBREADLINE = @TARGET_READLINE_LIBS@

# Object files for the SQLite library.
#
LIBOBJ = build.o dbbe.o dbbegdbm.o delete.o expr.o insert.o \
         main.o parse.o printf.o select.o table.o tokenize.o update.o \
         util.o vdbe.o where.o tclsqlite.o

# All of the source code files.
#
SRC = \
  $(TOP)/src/build.c \
  $(TOP)/src/dbbe.c \
  $(TOP)/src/dbbegdbm.c \
  $(TOP)/src/dbbe.h \
  $(TOP)/src/dbbemem.c \
  $(TOP)/src/delete.c \
  $(TOP)/src/expr.c \
  $(TOP)/src/insert.c \
  $(TOP)/src/main.c \
  $(TOP)/src/parse.y \
................................................................................

build.o:	$(TOP)/src/build.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/build.c

dbbe.o:	$(TOP)/src/dbbe.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/dbbe.c

dbbegdbm.o:	$(TOP)/src/dbbegdbm.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/dbbegdbm.c

main.o:	$(TOP)/src/main.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/main.c

parse.o:	parse.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c parse.c

parse.h:	parse.c

Changes to VERSION.

1
1.0.12
|
1
1.0.13

Changes to src/dbbe.c.

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** sqlite and the code that does the actually reading and writing
** of information to the disk.
**
** This file uses GDBM as the database backend.  It should be
** relatively simple to convert to a different database such
** as NDBM, SDBM, or BerkeleyDB.
**
** $Id: dbbe.c,v 1.19 2000/08/17 09:50:00 drh Exp $
*/
#include "sqliteInt.h"
#include <gdbm.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <time.h>

/*
** Information about each open disk file is an instance of this 
** structure.  There will only be one such structure for each
** disk file.  If the VDBE opens the same file twice (as will happen
** for a self-join, for example) then two DbbeCursor structures are
** created but there is only a single BeFile structure with an
** nRef of 2.
*/
typedef struct BeFile BeFile;
struct BeFile {
  char *zName;            /* Name of the file */
  GDBM_FILE dbf;          /* The file itself */
  int nRef;               /* Number of references */
  int delOnClose;         /* Delete when closing */
  int writeable;          /* Opened for writing */
  BeFile *pNext, *pPrev;  /* Next and previous on list of open files */
};

/*
** The following structure holds the current state of the RC4 algorithm.
** We use RC4 as a random number generator.  Each call to RC4 gives
** a random 8-bit number.
**
** Nothing in this file or anywhere else in SQLite does any kind of
** encryption.  The RC4 algorithm is being used as a PRNG (pseudo-random
** number generator) not as an encryption device.
*/
struct rc4 {
  int i, j;
  int s[256];
};

/*
** The complete database is an instance of the following structure.
*/
struct Dbbe {
  char *zDir;        /* The directory containing the database */
  int write;         /* True for write permission */
  BeFile *pOpen;     /* List of open files */
  int nTemp;         /* Number of temporary files created */
  FILE **apTemp;     /* Space to hold temporary file pointers */
  char **azTemp;     /* Names of the temporary files */
  struct rc4 rc4;    /* The random number generator */
};

/*
** An cursor into a database file is an instance of the following structure.
** There can only be a single BeFile structure for each disk file, but
** there can be multiple DbbeCursor structures.  Each DbbeCursor represents
** a cursor pointing to a particular part of the open BeFile.  The
** BeFile.nRef field hold a count of the number of DbbeCursor structures
** associated with the same disk file.
*/
struct DbbeCursor {
  Dbbe *pBe;         /* The database of which this record is a part */
  BeFile *pFile;     /* The database file for this table */
  datum key;         /* Most recently used key */
  datum data;        /* Most recent data */
  int needRewind;    /* Next key should be the first */
  int readPending;   /* The fetch hasn't actually been done yet */
};

/*
** Initialize the RC4 PRNG.  "seed" is a pointer to some random
** data used to initialize the PRNG.  
*/
static void rc4init(struct rc4 *p, char *seed, int seedlen){
  int i;
  char k[256];
  p->j = 0;
  p->i = 0;
  for(i=0; i<256; i++){
    p->s[i] = i;
    k[i] = seed[i%seedlen];
  }
  for(i=0; i<256; i++){
    int t;
    p->j = (p->j + p->s[i] + k[i]) & 0xff;
    t = p->s[p->j];
    p->s[p->j] = p->s[i];
    p->s[i] = t;
  }
}

/*
** Get a single 8-bit random value from the RC4 PRNG.
*/
static int rc4byte(struct rc4 *p){
  int t;
  p->i = (p->i + 1) & 0xff;
  p->j = (p->j + p->s[p->i]) & 0xff;
  t = p->s[p->i];
  p->s[p->i] = p->s[p->j];
  p->s[p->j] = t;
  t = p->s[p->i] + p->s[p->j];
  return t & 0xff;
}

/*
** The "mkdir()" function only takes one argument under Windows.
*/
#if OS_WIN
# define mkdir(A,B) mkdir(A)
#endif

/*
** This routine opens a new database.  For the GDBM driver
** implemented here, the database name is the name of the directory
** containing all the files of the database.





**
** If successful, a pointer to the Dbbe structure is returned.
** If there are errors, an appropriate error message is left
** in *pzErrMsg and NULL is returned.
*/
Dbbe *sqliteDbbeOpen(
  const char *zName,     /* The name of the database */
  int writeFlag,         /* True if we will be writing to the database */
  int createFlag,        /* True to create database if it doesn't exist */
  char **pzErrMsg        /* Write error messages (if any) here */
){
  Dbbe *pNew;
  struct stat statbuf;
  char *zMaster;




  if( !writeFlag ) createFlag = 0;
  if( stat(zName, &statbuf)!=0 ){
    if( createFlag ) mkdir(zName, 0750);
    if( stat(zName, &statbuf)!=0 ){
      sqliteSetString(pzErrMsg, createFlag ? 
         "can't find or create directory \"" : "can't find directory \"",
         zName, "\"", 0);
      return 0;




    }


  }
  if( !S_ISDIR(statbuf.st_mode) ){
    sqliteSetString(pzErrMsg, "not a directory: \"", zName, "\"", 0);
    return 0;
  }
  if( access(zName, writeFlag ? (X_OK|W_OK|R_OK) : (X_OK|R_OK)) ){
    sqliteSetString(pzErrMsg, "access permission denied", 0);
    return 0;
  }
  zMaster = 0;
  sqliteSetString(&zMaster, zName, "/" MASTER_NAME ".tbl", 0);
  if( stat(zMaster, &statbuf)==0
   && access(zMaster, writeFlag ? (W_OK|R_OK) : R_OK)!=0 ){
    sqliteSetString(pzErrMsg, "access permission denied for ", zMaster, 0);
    sqliteFree(zMaster);
    return 0;
  }
  sqliteFree(zMaster);
  pNew = sqliteMalloc(sizeof(Dbbe) + strlen(zName) + 1);
  if( pNew==0 ){
    sqliteSetString(pzErrMsg, "out of memory", 0);
    return 0;
  }
  pNew->zDir = (char*)&pNew[1];
  strcpy(pNew->zDir, zName);
  pNew->write = writeFlag;
  pNew->pOpen = 0;
  time(&statbuf.st_ctime);
  rc4init(&pNew->rc4, (char*)&statbuf, sizeof(statbuf));
  return pNew;
}

/*
** Completely shutdown the given database.  Close all files.  Free all memory.
*/
void sqliteDbbeClose(Dbbe *pBe){
  BeFile *pFile, *pNext;
  int i;
  for(pFile=pBe->pOpen; pFile; pFile=pNext){
    pNext = pFile->pNext;
    gdbm_close(pFile->dbf);
    memset(pFile, 0, sizeof(*pFile));   
    sqliteFree(pFile);
  }
  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]!=0 ){
      unlink(pBe->azTemp[i]);
      fclose(pBe->apTemp[i]);
      sqliteFree(pBe->azTemp[i]);
      pBe->apTemp[i] = 0;
      pBe->azTemp[i] = 0;
      break;
    }
  }
  sqliteFree(pBe->azTemp);
  sqliteFree(pBe->apTemp);
  memset(pBe, 0, sizeof(*pBe));
  sqliteFree(pBe);
}

/*
** Translate the name of an SQL table (or index) into the name 
** of a file that holds the key/data pairs for that table or
** index.  Space to hold the filename is obtained from
** sqliteMalloc() and must be freed by the calling function.
*/
static char *sqliteFileOfTable(Dbbe *pBe, const char *zTable){
  char *zFile = 0;
  int i;
  sqliteSetString(&zFile, pBe->zDir, "/", zTable, ".tbl", 0);
  if( zFile==0 ) return 0;
  for(i=strlen(pBe->zDir)+1; zFile[i]; i++){
    int c = zFile[i];
    if( isupper(c) ){
      zFile[i] = tolower(c);
    }else if( !isalnum(c) && c!='-' && c!='_' && c!='.' ){
      zFile[i] = '+';
    }
  }
  return zFile;
}

/*
** Generate a random filename with the given prefix.  The new filename
** is written into zBuf[].  The calling function must insure that
** zBuf[] is big enough to hold the prefix plus 20 or so extra
** characters.
**
** Very random names are chosen so that the chance of a
** collision with an existing filename is very very small.
*/
static void randomName(struct rc4 *pRc4, char *zBuf, char *zPrefix){
  int i, j;
  static const char zRandomChars[] = "abcdefghijklmnopqrstuvwxyz0123456789";
  strcpy(zBuf, zPrefix);
  j = strlen(zBuf);
  for(i=0; i<15; i++){
    int c = rc4byte(pRc4) % (sizeof(zRandomChars) - 1);
    zBuf[j++] = zRandomChars[c];
  }
  zBuf[j] = 0;
}

/*
** Open a new table cursor.  Write a pointer to the corresponding
** DbbeCursor structure into *ppCursr.  Return an integer success
** code:
**
**    SQLITE_OK          It worked!
**
**    SQLITE_NOMEM       sqliteMalloc() failed
**
**    SQLITE_PERM        Attempt to access a file for which file
**                       access permission is denied
**
**    SQLITE_BUSY        Another thread or process is already using
**                       the corresponding file and has that file locked.
**
**    SQLITE_READONLY    The current thread already has this file open
**                       readonly but you are trying to open for writing.
**                       (This can happen if a SELECT callback tries to
**                       do an UPDATE or DELETE.)
**
** If zTable is 0 or "", then a temporary database file is created and
** a cursor to that temporary file is opened.  The temporary file
** will be deleted from the disk when it is closed.
*/
int sqliteDbbeOpenCursor(
  Dbbe *pBe,              /* The database the table belongs to */
  const char *zTable,     /* The SQL name of the file to be opened */
  int writeable,          /* True to open for writing */
  DbbeCursor **ppCursr    /* Write the resulting table pointer here */
){
  char *zFile;            /* Name of the table file */
  DbbeCursor *pCursr;     /* The new table cursor */
  BeFile *pFile;          /* The underlying data file for this table */
  int rc = SQLITE_OK;     /* Return value */
  int rw_mask;            /* Permissions mask for opening a table */
  int mode;               /* Mode for opening a table */

  *ppCursr = 0;
  pCursr = sqliteMalloc( sizeof(*pCursr) );
  if( pCursr==0 ) return SQLITE_NOMEM;
  if( zTable ){
    zFile = sqliteFileOfTable(pBe, zTable);
    for(pFile=pBe->pOpen; pFile; pFile=pFile->pNext){
      if( strcmp(pFile->zName,zFile)==0 ) break;
    }
  }else{
    pFile = 0;
    zFile = 0;
  }
  if( pFile==0 ){
    if( writeable ){
      rw_mask = GDBM_WRCREAT | GDBM_FAST;
      mode = 0640;
    }else{
      rw_mask = GDBM_READER;
      mode = 0640;
    }
    pFile = sqliteMalloc( sizeof(*pFile) );
    if( pFile==0 ){
      sqliteFree(zFile);
      return SQLITE_NOMEM;
    }
    if( zFile ){
      if( !writeable || pBe->write ){
        pFile->dbf = gdbm_open(zFile, 0, rw_mask, mode, 0);
      }else{
        pFile->dbf = 0;
      }
    }else{
      int limit;
      struct rc4 *pRc4;
      char zRandom[50];
      pRc4 = &pBe->rc4;
      zFile = 0;
      limit = 5;
      do {
        randomName(&pBe->rc4, zRandom, "_temp_table_");
        sqliteFree(zFile);
        zFile = sqliteFileOfTable(pBe, zRandom);
        pFile->dbf = gdbm_open(zFile, 0, rw_mask, mode, 0);
      }while( pFile->dbf==0 && limit-- >= 0);
      pFile->delOnClose = 1;
    }
    pFile->writeable = writeable;
    pFile->zName = zFile;
    pFile->nRef = 1;
    pFile->pPrev = 0;
    if( pBe->pOpen ){
      pBe->pOpen->pPrev = pFile;
    }
    pFile->pNext = pBe->pOpen;
    pBe->pOpen = pFile;
    if( pFile->dbf==0 ){
      if( !writeable && access(zFile,0) ){
        /* Trying to read a non-existant file.  This is OK.  All the
        ** reads will return empty, which is what we want. */
        rc = SQLITE_OK;   
      }else if( pBe->write==0 ){
        rc = SQLITE_READONLY;
      }else if( access(zFile,W_OK|R_OK) ){
        rc = SQLITE_PERM;
      }else{
        rc = SQLITE_BUSY;
      }
    }
  }else{
    sqliteFree(zFile);
    pFile->nRef++;
    if( writeable && !pFile->writeable ){
      rc = SQLITE_READONLY;
    }
  }
  pCursr->pBe = pBe;
  pCursr->pFile = pFile;
  pCursr->readPending = 0;
  pCursr->needRewind = 1;
  if( rc!=SQLITE_OK ){
    sqliteDbbeCloseCursor(pCursr);
    *ppCursr = 0;
  }else{
    *ppCursr = pCursr;
  }
  return rc;
}

/*
** Drop a table from the database.  The file on the disk that corresponds
** to this table is deleted.
*/
void sqliteDbbeDropTable(Dbbe *pBe, const char *zTable){
  char *zFile;            /* Name of the table file */

  zFile = sqliteFileOfTable(pBe, zTable);
  unlink(zFile);
  sqliteFree(zFile);
}

/*
** Reorganize a table to reduce search times and disk usage.
*/
int sqliteDbbeReorganizeTable(Dbbe *pBe, const char *zTable){
  DbbeCursor *pCrsr;
  int rc;

  rc = sqliteDbbeOpenCursor(pBe, zTable, 1, &pCrsr);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( pCrsr && pCrsr->pFile && pCrsr->pFile->dbf ){
    gdbm_reorganize(pCrsr->pFile->dbf);
  }
  if( pCrsr ){
    sqliteDbbeCloseCursor(pCrsr);
  }
  return SQLITE_OK;
}

/*
** Close a cursor previously opened by sqliteDbbeOpenCursor().
**
** There can be multiple cursors pointing to the same open file.
** The underlying file is not closed until all cursors have been
** closed.  This routine decrements the BeFile.nref field of the
** underlying file and closes the file when nref reaches 0.
*/
void sqliteDbbeCloseCursor(DbbeCursor *pCursr){
  BeFile *pFile;
  Dbbe *pBe;
  if( pCursr==0 ) return;
  pFile = pCursr->pFile;
  pBe = pCursr->pBe;
  pFile->nRef--;
  if( pFile->dbf!=NULL ){
    gdbm_sync(pFile->dbf);
  }
  if( pFile->nRef<=0 ){
    if( pFile->dbf!=NULL ){
      gdbm_close(pFile->dbf);
    }
    if( pFile->pPrev ){
      pFile->pPrev->pNext = pFile->pNext;
    }else{
      pBe->pOpen = pFile->pNext;
    }
    if( pFile->pNext ){
      pFile->pNext->pPrev = pFile->pPrev;
    }
    if( pFile->delOnClose ){
      unlink(pFile->zName);
    }
    sqliteFree(pFile->zName);
    memset(pFile, 0, sizeof(*pFile));
    sqliteFree(pFile);
  }
  if( pCursr->key.dptr ) free(pCursr->key.dptr);
  if( pCursr->data.dptr ) free(pCursr->data.dptr);
  memset(pCursr, 0, sizeof(*pCursr));
  sqliteFree(pCursr);
}

/*
** Clear the given datum
*/
static void datumClear(datum *p){
  if( p->dptr ) free(p->dptr);
  p->dptr = 0;
  p->dsize = 0;
}

/*
** Fetch a single record from an open cursor.  Return 1 on success
** and 0 on failure.
*/
int sqliteDbbeFetch(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  key.dsize = nKey;
  key.dptr = pKey;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, key);
  }
  return pCursr->data.dptr!=0;
}

/*
** Return 1 if the given key is already in the table.  Return 0
** if it is not.
*/
int sqliteDbbeTest(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int result = 0;
  key.dsize = nKey;
  key.dptr = pKey;
  if( pCursr->pFile && pCursr->pFile->dbf ){
    result = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return result;
}

/*
** Copy bytes from the current key or data into a buffer supplied by
** the calling function.  Return the number of bytes copied.
*/
int sqliteDbbeCopyKey(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( offset>=pCursr->key.dsize ) return 0;
  if( offset+size>pCursr->key.dsize ){
    n = pCursr->key.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->key.dptr[offset], n);
  return n;
}
int sqliteDbbeCopyData(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset>=pCursr->data.dsize ) return 0;
  if( offset+size>pCursr->data.dsize ){
    n = pCursr->data.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->data.dptr[offset], n);
  return n;
}

/*
** Return a pointer to bytes from the key or data.  The data returned
** is ephemeral.
*/
char *sqliteDbbeReadKey(DbbeCursor *pCursr, int offset){
  if( offset<0 || offset>=pCursr->key.dsize ) return "";
  return &pCursr->key.dptr[offset];
}
char *sqliteDbbeReadData(DbbeCursor *pCursr, int offset){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset<0 || offset>=pCursr->data.dsize ) return "";
  return &pCursr->data.dptr[offset];
}

/*
** Return the total number of bytes in either data or key.
*/
int sqliteDbbeKeyLength(DbbeCursor *pCursr){
  return pCursr->key.dsize;
}
int sqliteDbbeDataLength(DbbeCursor *pCursr){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  return pCursr->data.dsize;
}

/*
** Make is so that the next call to sqliteNextKey() finds the first
** key of the table.
*/
int sqliteDbbeRewind(DbbeCursor *pCursr){
  pCursr->needRewind = 1;
  return SQLITE_OK;
}

/*
** Read the next key from the table.  Return 1 on success.  Return
** 0 if there are no more keys.
*/
int sqliteDbbeNextKey(DbbeCursor *pCursr){
  datum nextkey;
  int rc;
  if( pCursr==0 || pCursr->pFile==0 || pCursr->pFile->dbf==0 ){
    pCursr->readPending = 0;
    return 0;
  }
  if( pCursr->needRewind ){
    nextkey = gdbm_firstkey(pCursr->pFile->dbf);
    pCursr->needRewind = 0;
  }else{
    nextkey = gdbm_nextkey(pCursr->pFile->dbf, pCursr->key);
  }
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  pCursr->key = nextkey;
  if( pCursr->key.dptr ){
    pCursr->readPending = 1;
    rc = 1;
  }else{
    pCursr->needRewind = 1;
    pCursr->readPending = 0;
    rc = 0;
  }
  return rc;
}

/*
** Get a new integer key.
*/
int sqliteDbbeNew(DbbeCursor *pCursr){
  int iKey;
  datum key;
  int go = 1;
  int i;
  struct rc4 *pRc4;

  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return 1;
  pRc4 = &pCursr->pBe->rc4;
  while( go ){
    iKey = 0;
    for(i=0; i<4; i++){
      iKey = (iKey<<8) + rc4byte(pRc4);
    }
    if( iKey==0 ) continue;
    key.dptr = (char*)&iKey;
    key.dsize = 4;
    go = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return iKey;
}   

/*
** Write an entry into the table.  Overwrite any prior entry with the
** same key.
*/
int sqliteDbbePut(DbbeCursor *pCursr, int nKey,char *pKey,int nData,char *pData){
  datum data, key;
  int rc;
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  data.dsize = nData;
  data.dptr = pData;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_store(pCursr->pFile->dbf, key, data, GDBM_REPLACE);
  if( rc ) rc = SQLITE_ERROR;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  return rc;
}

/*
** Remove an entry from a table, if the entry exists.
*/
int sqliteDbbeDelete(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int rc;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_delete(pCursr->pFile->dbf, key);
  if( rc ) rc = SQLITE_ERROR;
  return rc;
}

/*
** Open a temporary file.  The file should be deleted when closed.
**
** Note that we can't use the old Unix trick of opening the file
** and then immediately unlinking the file.  That works great
** under Unix, but fails when we try to port to Windows.
*/
int sqliteDbbeOpenTempFile(Dbbe *pBe, FILE **ppFile){
  char *zFile;         /* Full name of the temporary file */
  char zBuf[50];       /* Base name of the temporary file */
  int i;               /* Loop counter */
  int limit;           /* Prevent an infinite loop */
  int rc = SQLITE_OK;  /* Value returned by this function */

  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]==0 ) break;
  }
  if( i>=pBe->nTemp ){
    pBe->nTemp++;
    pBe->apTemp = sqliteRealloc(pBe->apTemp, pBe->nTemp*sizeof(FILE*) );
    pBe->azTemp = sqliteRealloc(pBe->azTemp, pBe->nTemp*sizeof(char*) );
  }
  if( pBe->apTemp==0 ){
    *ppFile = 0;
    return SQLITE_NOMEM;
  }
  limit = 4;
  zFile = 0;
  do{
    randomName(&pBe->rc4, zBuf, "/_temp_file_");
    sqliteFree(zFile);
    zFile = 0;
    sqliteSetString(&zFile, pBe->zDir, zBuf, 0);
  }while( access(zFile,0)==0 && limit-- >= 0 );
  *ppFile = pBe->apTemp[i] = fopen(zFile, "w+");
  if( pBe->apTemp[i]==0 ){
    rc = SQLITE_ERROR;
    sqliteFree(zFile);
    pBe->azTemp[i] = 0;
  }else{
    pBe->azTemp[i] = zFile;
  }
  return rc;
}

/*
** Close a temporary file opened using sqliteDbbeOpenTempFile()
*/
void sqliteDbbeCloseTempFile(Dbbe *pBe, FILE *f){
  int i;
  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]==f ){
      unlink(pBe->azTemp[i]);
      sqliteFree(pBe->azTemp[i]);
      pBe->apTemp[i] = 0;
      pBe->azTemp[i] = 0;
      break;
    }
  }
  fclose(f);
}







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** sqlite and the code that does the actually reading and writing
** of information to the disk.
**
** This file uses GDBM as the database backend.  It should be
** relatively simple to convert to a different database such
** as NDBM, SDBM, or BerkeleyDB.
**
** $Id: dbbe.c,v 1.20 2000/10/19 01:49:02 drh Exp $
*/
#include "sqliteInt.h"






/*









































































































** This routine opens a new database.  It looks at the first


** few characters of the database name to try to determine what
** kind of database to open.  If the first characters are "gdbm:",
** then it uses the GDBM driver.  If the first few characters are
** "memory:" then it uses the in-memory driver.  If there is no
** match, the default to the GDBM driver.
**
** If successful, a pointer to the Dbbe structure is returned.
** If there are errors, an appropriate error message is left
** in *pzErrMsg and NULL is returned.
*/
Dbbe *sqliteDbbeOpen(
  const char *zName,     /* The name of the database */
  int writeFlag,         /* True if we will be writing to the database */
  int createFlag,        /* True to create database if it doesn't exist */
  char **pzErrMsg        /* Write error messages (if any) here */
){



  extern Dbbe *sqliteGdbmOpen(const char*,int,int,char**);
  if( strncmp(zName, "gdbm:", 5)==0 ){
    return sqliteGdbmOpen(&zName[5], writeFlag, createFlag, pzErrMsg);
  }








#if 0
  if( strncmp(zName, "memory:", 7)==0 ){
    extern Dbbe *sqliteMemOpen(const char*,int,int,char**);
    return sqliteMemOpen(&zName[7], writeFlag, createFlag, pzErrMsg);
  }
#endif
  return sqliteGdbmOpen(zName, writeFlag, createFlag, pzErrMsg);
}





















































































































































































































































































































































































































































































































































































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** This file defines the interface to the database backend (Dbbe).
**
** The database backend is designed to be as general as possible
** so that it can easily be replaced by a different backend.
** This library was originally designed to support the following
** backends: GDBM, NDBM, SDBM, Berkeley DB.
**
** $Id: dbbe.h,v 1.7 2000/08/17 09:50:00 drh Exp $
*/
#ifndef _SQLITE_DBBE_H_
#define _SQLITE_DBBE_H_
#include <stdio.h>

/*
** The database backend supports two opaque structures.  A Dbbe is
................................................................................
** The DbbeCursor structure holds some state information, such as
** the key and data from the last retrieval.  For this reason, 
** the backend must allow the creation of multiple independent
** DbbeCursor structures for each table in the database.
*/
typedef struct Dbbe Dbbe;
typedef struct DbbeCursor DbbeCursor;


/*
** The 18 interface routines.





*/

/* Open a complete database */
Dbbe *sqliteDbbeOpen(const char *zName, int write, int create, char **pzErr);






/* Close the whole database. */
void sqliteDbbeClose(Dbbe*);


/* Open a cursor into particular file of a previously opened database.
** Create the file if it doesn't already exist and writeable!=0.  zName
** is the base name of the file to be opened.  This routine will add
** an appropriate path and extension to the filename to locate the 
** actual file.
**
** If zName is 0 or "", then a temporary file is created that
** will be deleted when closed.
*/
int sqliteDbbeOpenCursor(Dbbe*, const char *zName, int writeable, DbbeCursor**);

/* Delete a table from the database */
void sqliteDbbeDropTable(Dbbe*, const char *zTableName);

/* Reorganize a table to speed access or reduce its disk usage */
int sqliteDbbeReorganizeTable(Dbbe*, const char *zTableName);

/* Close a cursor */
void sqliteDbbeCloseCursor(DbbeCursor*);

/* Fetch an entry from a table with the given key.  Return 1 if
** successful and 0 if no such entry exists.
*/
int sqliteDbbeFetch(DbbeCursor*, int nKey, char *pKey);

/* Return 1 if the given key is already in the table.  Return 0
** if it is not.
*/
int sqliteDbbeTest(DbbeCursor*, int nKey, char *pKey);

/* Retrieve the key or data used for the last fetch.  Only size
** bytes are read beginning with the offset-th byte.  The return
** value is the actual number of bytes read.
*/
int sqliteDbbeCopyKey(DbbeCursor*, int offset, int size, char *zBuf);
int sqliteDbbeCopyData(DbbeCursor*, int offset, int size, char *zBuf);

/* Retrieve the key or data.  The result is ephemeral.  In other words,
** the result is stored in a buffer that might be overwritten on the next
** call to any DBBE routine.  If the results are needed for longer than
** that, you must make a copy.
*/
char *sqliteDbbeReadKey(DbbeCursor*, int offset);
char *sqliteDbbeReadData(DbbeCursor*, int offset);

/* Return the length of the most recently fetched key or data. */
int sqliteDbbeKeyLength(DbbeCursor*);
int sqliteDbbeDataLength(DbbeCursor*);


/* Retrieve the next entry in the table.  The first key is retrieved
** the first time this routine is called, or after a call to
** sqliteDbbeRewind().  The return value is 1 if there is another
** entry, or 0 if there are no more entries. */
int sqliteDbbeNextKey(DbbeCursor*);

/* Make it so that the next call to sqliteDbbeNextKey() returns
** the first entry of the table. */
int sqliteDbbeRewind(DbbeCursor*);

/* Get a new integer key for this table. */
int sqliteDbbeNew(DbbeCursor*);

/* Write an entry into a table.  If another entry already exists with
** the same key, the old entry is discarded first.
*/
int sqliteDbbePut(DbbeCursor*, int nKey, char *pKey, int nData, char *pData);

/* Remove an entry from the table */
int sqliteDbbeDelete(DbbeCursor*, int nKey, char *pKey);

/* Open a file suitable for temporary storage */
int sqliteDbbeOpenTempFile(Dbbe*, FILE**);

/* Close a temporary file */
void sqliteDbbeCloseTempFile(Dbbe *, FILE *);


#endif /* defined(_SQLITE_DBBE_H_) */







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** This file defines the interface to the database backend (Dbbe).
**
** The database backend is designed to be as general as possible
** so that it can easily be replaced by a different backend.
** This library was originally designed to support the following
** backends: GDBM, NDBM, SDBM, Berkeley DB.
**
** $Id: dbbe.h,v 1.8 2000/10/19 01:49:02 drh Exp $
*/
#ifndef _SQLITE_DBBE_H_
#define _SQLITE_DBBE_H_
#include <stdio.h>

/*
** The database backend supports two opaque structures.  A Dbbe is
................................................................................
** The DbbeCursor structure holds some state information, such as
** the key and data from the last retrieval.  For this reason, 
** the backend must allow the creation of multiple independent
** DbbeCursor structures for each table in the database.
*/
typedef struct Dbbe Dbbe;
typedef struct DbbeCursor DbbeCursor;


/*

** Open a complete database.
**
** If the database name begins with "gdbm:" the GDBM driver is used.
** If the name begins with "memory:" the in-memory driver is used.
** The default driver is GDBM.
*/


Dbbe *sqliteDbbeOpen(const char *zName, int write, int create, char **pzErr);

/*
** This is the structure returned by sqliteDbbeOpen().  It contains pointers
** to all access routines for the database backend.
*/
struct Dbbe {
  /* Close the whole database. */

  void (*Close)(Dbbe*);

  /* Open a cursor into particular file of a previously opened database.
  ** Create the file if it doesn't already exist and writeable!=0.  zName
  ** is the base name of the file to be opened.  This routine will add
  ** an appropriate path and extension to the filename to locate the 
  ** actual file.
  **
  ** If zName is 0 or "", then a temporary file is created that
  ** will be deleted when closed.
  */
  int (*OpenCursor)(Dbbe*, const char *zName, int writeable, DbbeCursor**);

  /* Delete a table from the database */
  void (*DropTable)(Dbbe*, const char *zTableName);

  /* Reorganize a table to speed access or reduce its disk usage */
  int (*ReorganizeTable)(Dbbe*, const char *zTableName);

  /* Close a cursor */
  void (*CloseCursor)(DbbeCursor*);

  /* Fetch an entry from a table with the given key.  Return 1 if
  ** successful and 0 if no such entry exists.
  */
  int (*Fetch)(DbbeCursor*, int nKey, char *pKey);

  /* Return 1 if the given key is already in the table.  Return 0
  ** if it is not.
  */
  int (*Test)(DbbeCursor*, int nKey, char *pKey);

  /* Retrieve the key or data used for the last fetch.  Only size
  ** bytes are read beginning with the offset-th byte.  The return
  ** value is the actual number of bytes read.
  */
  int (*CopyKey)(DbbeCursor*, int offset, int size, char *zBuf);
  int (*CopyData)(DbbeCursor*, int offset, int size, char *zBuf);

  /* Retrieve the key or data.  The result is ephemeral.  In other words,
  ** the result is stored in a buffer that might be overwritten on the next
  ** call to any DBBE routine.  If the results are needed for longer than
  ** that, you must make a copy.
  */
  char *(*ReadKey)(DbbeCursor*, int offset);
  char *(*ReadData)(DbbeCursor*, int offset);

  /* Return the length of the most recently fetched key or data. */
  int (*KeyLength)(DbbeCursor*);

  int (*DataLength)(DbbeCursor*);

  /* Retrieve the next entry in the table.  The first key is retrieved
  ** the first time this routine is called, or after a call to
  ** Dbbe.Rewind().  The return value is 1 if there is another
  ** entry, or 0 if there are no more entries. */
  int (*NextKey)(DbbeCursor*);

  /* Make it so that the next call to Dbbe.NextKey() returns
  ** the first entry of the table. */
  int (*Rewind)(DbbeCursor*);

  /* Get a new integer key for this table. */
  int (*New)(DbbeCursor*);

  /* Write an entry into a table.  If another entry already exists with
  ** the same key, the old entry is discarded first.
  */
  int (*Put)(DbbeCursor*, int nKey, char *pKey, int nData, char *pData);

  /* Remove an entry from the table */
  int (*Delete)(DbbeCursor*, int nKey, char *pKey);

  /* Open a file suitable for temporary storage */
  int (*OpenTempFile)(Dbbe*, FILE**);

  /* Close a temporary file */
  void (*CloseTempFile)(Dbbe *, FILE *);
};

#endif /* defined(_SQLITE_DBBE_H_) */

Added src/dbbegdbm.c.

















































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































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/*
** Copyright (c) 2000 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License as published by the Free Software Foundation; either
** version 2 of the License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
** 
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains code to implement the database backend (DBBE)
** for sqlite.  The database backend is the interface between
** sqlite and the code that does the actually reading and writing
** of information to the disk.
**
** This file uses GDBM as the database backend.  It should be
** relatively simple to convert to a different database such
** as NDBM, SDBM, or BerkeleyDB.
**
** $Id: dbbegdbm.c,v 1.1 2000/10/19 01:49:02 drh Exp $
*/
#include "sqliteInt.h"
#include <gdbm.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <time.h>

/*
** Information about each open disk file is an instance of this 
** structure.  There will only be one such structure for each
** disk file.  If the VDBE opens the same file twice (as will happen
** for a self-join, for example) then two DbbeCursor structures are
** created but there is only a single BeFile structure with an
** nRef of 2.
*/
typedef struct BeFile BeFile;
struct BeFile {
  char *zName;            /* Name of the file */
  GDBM_FILE dbf;          /* The file itself */
  int nRef;               /* Number of references */
  int delOnClose;         /* Delete when closing */
  int writeable;          /* Opened for writing */
  BeFile *pNext, *pPrev;  /* Next and previous on list of open files */
};

/*
** The following structure holds the current state of the RC4 algorithm.
** We use RC4 as a random number generator.  Each call to RC4 gives
** a random 8-bit number.
**
** Nothing in this file or anywhere else in SQLite does any kind of
** encryption.  The RC4 algorithm is being used as a PRNG (pseudo-random
** number generator) not as an encryption device.
*/
struct rc4 {
  int i, j;
  int s[256];
};

/*
** The following structure contains all information used by GDBM
** database driver.  This is a subclass of the Dbbe structure.
*/
typedef struct Dbbex Dbbex;
struct Dbbex {
  Dbbe dbbe;         /* The base class */
  char *zDir;        /* The directory containing the database */
  int write;         /* True for write permission */
  BeFile *pOpen;     /* List of open files */
  int nTemp;         /* Number of temporary files created */
  FILE **apTemp;     /* Space to hold temporary file pointers */
  char **azTemp;     /* Names of the temporary files */
  struct rc4 rc4;    /* The random number generator */
};

/*
** An cursor into a database file is an instance of the following structure.
** There can only be a single BeFile structure for each disk file, but
** there can be multiple DbbeCursor structures.  Each DbbeCursor represents
** a cursor pointing to a particular part of the open BeFile.  The
** BeFile.nRef field hold a count of the number of DbbeCursor structures
** associated with the same disk file.
*/
struct DbbeCursor {
  Dbbex *pBe;        /* The database of which this record is a part */
  BeFile *pFile;     /* The database file for this table */
  datum key;         /* Most recently used key */
  datum data;        /* Most recent data */
  int needRewind;    /* Next key should be the first */
  int readPending;   /* The fetch hasn't actually been done yet */
};

/*
** Initialize the RC4 PRNG.  "seed" is a pointer to some random
** data used to initialize the PRNG.  
*/
static void rc4init(struct rc4 *p, char *seed, int seedlen){
  int i;
  char k[256];
  p->j = 0;
  p->i = 0;
  for(i=0; i<256; i++){
    p->s[i] = i;
    k[i] = seed[i%seedlen];
  }
  for(i=0; i<256; i++){
    int t;
    p->j = (p->j + p->s[i] + k[i]) & 0xff;
    t = p->s[p->j];
    p->s[p->j] = p->s[i];
    p->s[i] = t;
  }
}

/*
** Get a single 8-bit random value from the RC4 PRNG.
*/
static int rc4byte(struct rc4 *p){
  int t;
  p->i = (p->i + 1) & 0xff;
  p->j = (p->j + p->s[p->i]) & 0xff;
  t = p->s[p->i];
  p->s[p->i] = p->s[p->j];
  p->s[p->j] = t;
  t = p->s[p->i] + p->s[p->j];
  return t & 0xff;
}

/*
** The "mkdir()" function only takes one argument under Windows.
*/
#if OS_WIN
# define mkdir(A,B) mkdir(A)
#endif

/*
** Forward declaration
*/
static void sqliteGdbmCloseCursor(DbbeCursor *pCursr);

/*
** Completely shutdown the given database.  Close all files.  Free all memory.
*/
static void sqliteGdbmClose(Dbbe *pDbbe){
  Dbbex *pBe = (Dbbex*)pDbbe;
  BeFile *pFile, *pNext;
  int i;
  for(pFile=pBe->pOpen; pFile; pFile=pNext){
    pNext = pFile->pNext;
    gdbm_close(pFile->dbf);
    memset(pFile, 0, sizeof(*pFile));   
    sqliteFree(pFile);
  }
  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]!=0 ){
      unlink(pBe->azTemp[i]);
      fclose(pBe->apTemp[i]);
      sqliteFree(pBe->azTemp[i]);
      pBe->apTemp[i] = 0;
      pBe->azTemp[i] = 0;
      break;
    }
  }
  sqliteFree(pBe->azTemp);
  sqliteFree(pBe->apTemp);
  memset(pBe, 0, sizeof(*pBe));
  sqliteFree(pBe);
}

/*
** Translate the name of an SQL table (or index) into the name 
** of a file that holds the key/data pairs for that table or
** index.  Space to hold the filename is obtained from
** sqliteMalloc() and must be freed by the calling function.
*/
static char *sqliteFileOfTable(Dbbex *pBe, const char *zTable){
  char *zFile = 0;
  int i;
  sqliteSetString(&zFile, pBe->zDir, "/", zTable, ".tbl", 0);
  if( zFile==0 ) return 0;
  for(i=strlen(pBe->zDir)+1; zFile[i]; i++){
    int c = zFile[i];
    if( isupper(c) ){
      zFile[i] = tolower(c);
    }else if( !isalnum(c) && c!='-' && c!='_' && c!='.' ){
      zFile[i] = '+';
    }
  }
  return zFile;
}

/*
** Generate a random filename with the given prefix.  The new filename
** is written into zBuf[].  The calling function must insure that
** zBuf[] is big enough to hold the prefix plus 20 or so extra
** characters.
**
** Very random names are chosen so that the chance of a
** collision with an existing filename is very very small.
*/
static void randomName(struct rc4 *pRc4, char *zBuf, char *zPrefix){
  int i, j;
  static const char zRandomChars[] = "abcdefghijklmnopqrstuvwxyz0123456789";
  strcpy(zBuf, zPrefix);
  j = strlen(zBuf);
  for(i=0; i<15; i++){
    int c = rc4byte(pRc4) % (sizeof(zRandomChars) - 1);
    zBuf[j++] = zRandomChars[c];
  }
  zBuf[j] = 0;
}

/*
** Open a new table cursor.  Write a pointer to the corresponding
** DbbeCursor structure into *ppCursr.  Return an integer success
** code:
**
**    SQLITE_OK          It worked!
**
**    SQLITE_NOMEM       sqliteMalloc() failed
**
**    SQLITE_PERM        Attempt to access a file for which file
**                       access permission is denied
**
**    SQLITE_BUSY        Another thread or process is already using
**                       the corresponding file and has that file locked.
**
**    SQLITE_READONLY    The current thread already has this file open
**                       readonly but you are trying to open for writing.
**                       (This can happen if a SELECT callback tries to
**                       do an UPDATE or DELETE.)
**
** If zTable is 0 or "", then a temporary database file is created and
** a cursor to that temporary file is opened.  The temporary file
** will be deleted from the disk when it is closed.
*/
static int sqliteGdbmOpenCursor(
  Dbbe *pDbbe,            /* The database the table belongs to */
  const char *zTable,     /* The SQL name of the file to be opened */
  int writeable,          /* True to open for writing */
  DbbeCursor **ppCursr    /* Write the resulting table pointer here */
){
  char *zFile;            /* Name of the table file */
  DbbeCursor *pCursr;     /* The new table cursor */
  BeFile *pFile;          /* The underlying data file for this table */
  int rc = SQLITE_OK;     /* Return value */
  int rw_mask;            /* Permissions mask for opening a table */
  int mode;               /* Mode for opening a table */
  Dbbex *pBe = (Dbbex*)pDbbe;

  *ppCursr = 0;
  pCursr = sqliteMalloc( sizeof(*pCursr) );
  if( pCursr==0 ) return SQLITE_NOMEM;
  if( zTable ){
    zFile = sqliteFileOfTable(pBe, zTable);
    for(pFile=pBe->pOpen; pFile; pFile=pFile->pNext){
      if( strcmp(pFile->zName,zFile)==0 ) break;
    }
  }else{
    pFile = 0;
    zFile = 0;
  }
  if( pFile==0 ){
    if( writeable ){
      rw_mask = GDBM_WRCREAT | GDBM_FAST;
      mode = 0640;
    }else{
      rw_mask = GDBM_READER;
      mode = 0640;
    }
    pFile = sqliteMalloc( sizeof(*pFile) );
    if( pFile==0 ){
      sqliteFree(zFile);
      return SQLITE_NOMEM;
    }
    if( zFile ){
      if( !writeable || pBe->write ){
        pFile->dbf = gdbm_open(zFile, 0, rw_mask, mode, 0);
      }else{
        pFile->dbf = 0;
      }
    }else{
      int limit;
      struct rc4 *pRc4;
      char zRandom[50];
      pRc4 = &pBe->rc4;
      zFile = 0;
      limit = 5;
      do {
        randomName(&pBe->rc4, zRandom, "_temp_table_");
        sqliteFree(zFile);
        zFile = sqliteFileOfTable(pBe, zRandom);
        pFile->dbf = gdbm_open(zFile, 0, rw_mask, mode, 0);
      }while( pFile->dbf==0 && limit-- >= 0);
      pFile->delOnClose = 1;
    }
    pFile->writeable = writeable;
    pFile->zName = zFile;
    pFile->nRef = 1;
    pFile->pPrev = 0;
    if( pBe->pOpen ){
      pBe->pOpen->pPrev = pFile;
    }
    pFile->pNext = pBe->pOpen;
    pBe->pOpen = pFile;
    if( pFile->dbf==0 ){
      if( !writeable && access(zFile,0) ){
        /* Trying to read a non-existant file.  This is OK.  All the
        ** reads will return empty, which is what we want. */
        rc = SQLITE_OK;   
      }else if( pBe->write==0 ){
        rc = SQLITE_READONLY;
      }else if( access(zFile,W_OK|R_OK) ){
        rc = SQLITE_PERM;
      }else{
        rc = SQLITE_BUSY;
      }
    }
  }else{
    sqliteFree(zFile);
    pFile->nRef++;
    if( writeable && !pFile->writeable ){
      rc = SQLITE_READONLY;
    }
  }
  pCursr->pBe = pBe;
  pCursr->pFile = pFile;
  pCursr->readPending = 0;
  pCursr->needRewind = 1;
  if( rc!=SQLITE_OK ){
    sqliteGdbmCloseCursor(pCursr);
    *ppCursr = 0;
  }else{
    *ppCursr = pCursr;
  }
  return rc;
}

/*
** Drop a table from the database.  The file on the disk that corresponds
** to this table is deleted.
*/
static void sqliteGdbmDropTable(Dbbe *pBe, const char *zTable){
  char *zFile;            /* Name of the table file */

  zFile = sqliteFileOfTable((Dbbex*)pBe, zTable);
  unlink(zFile);
  sqliteFree(zFile);
}

/*
** Close a cursor previously opened by sqliteGdbmOpenCursor().
**
** There can be multiple cursors pointing to the same open file.
** The underlying file is not closed until all cursors have been
** closed.  This routine decrements the BeFile.nref field of the
** underlying file and closes the file when nref reaches 0.
*/
static void sqliteGdbmCloseCursor(DbbeCursor *pCursr){
  BeFile *pFile;
  Dbbex *pBe;
  if( pCursr==0 ) return;
  pFile = pCursr->pFile;
  pBe = pCursr->pBe;
  pFile->nRef--;
  if( pFile->dbf!=NULL ){
    gdbm_sync(pFile->dbf);
  }
  if( pFile->nRef<=0 ){
    if( pFile->dbf!=NULL ){
      gdbm_close(pFile->dbf);
    }
    if( pFile->pPrev ){
      pFile->pPrev->pNext = pFile->pNext;
    }else{
      pBe->pOpen = pFile->pNext;
    }
    if( pFile->pNext ){
      pFile->pNext->pPrev = pFile->pPrev;
    }
    if( pFile->delOnClose ){
      unlink(pFile->zName);
    }
    sqliteFree(pFile->zName);
    memset(pFile, 0, sizeof(*pFile));
    sqliteFree(pFile);
  }
  if( pCursr->key.dptr ) free(pCursr->key.dptr);
  if( pCursr->data.dptr ) free(pCursr->data.dptr);
  memset(pCursr, 0, sizeof(*pCursr));
  sqliteFree(pCursr);
}

/*
** Reorganize a table to reduce search times and disk usage.
*/
static int sqliteGdbmReorganizeTable(Dbbe *pBe, const char *zTable){
  DbbeCursor *pCrsr;
  int rc;

  rc = sqliteGdbmOpenCursor(pBe, zTable, 1, &pCrsr);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( pCrsr && pCrsr->pFile && pCrsr->pFile->dbf ){
    gdbm_reorganize(pCrsr->pFile->dbf);
  }
  if( pCrsr ){
    sqliteGdbmCloseCursor(pCrsr);
  }
  return SQLITE_OK;
}

/*
** Clear the given datum
*/
static void datumClear(datum *p){
  if( p->dptr ) free(p->dptr);
  p->dptr = 0;
  p->dsize = 0;
}

/*
** Fetch a single record from an open cursor.  Return 1 on success
** and 0 on failure.
*/
static int sqliteGdbmFetch(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  key.dsize = nKey;
  key.dptr = pKey;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, key);
  }
  return pCursr->data.dptr!=0;
}

/*
** Return 1 if the given key is already in the table.  Return 0
** if it is not.
*/
static int sqliteGdbmTest(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int result = 0;
  key.dsize = nKey;
  key.dptr = pKey;
  if( pCursr->pFile && pCursr->pFile->dbf ){
    result = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return result;
}

/*
** Copy bytes from the current key or data into a buffer supplied by
** the calling function.  Return the number of bytes copied.
*/
static
int sqliteGdbmCopyKey(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( offset>=pCursr->key.dsize ) return 0;
  if( offset+size>pCursr->key.dsize ){
    n = pCursr->key.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->key.dptr[offset], n);
  return n;
}
static
int sqliteGdbmCopyData(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset>=pCursr->data.dsize ) return 0;
  if( offset+size>pCursr->data.dsize ){
    n = pCursr->data.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->data.dptr[offset], n);
  return n;
}

/*
** Return a pointer to bytes from the key or data.  The data returned
** is ephemeral.
*/
static char *sqliteGdbmReadKey(DbbeCursor *pCursr, int offset){
  if( offset<0 || offset>=pCursr->key.dsize ) return "";
  return &pCursr->key.dptr[offset];
}
static char *sqliteGdbmReadData(DbbeCursor *pCursr, int offset){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset<0 || offset>=pCursr->data.dsize ) return "";
  return &pCursr->data.dptr[offset];
}

/*
** Return the total number of bytes in either data or key.
*/
static int sqliteGdbmKeyLength(DbbeCursor *pCursr){
  return pCursr->key.dsize;
}
static int sqliteGdbmDataLength(DbbeCursor *pCursr){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  return pCursr->data.dsize;
}

/*
** Make is so that the next call to sqliteNextKey() finds the first
** key of the table.
*/
static int sqliteGdbmRewind(DbbeCursor *pCursr){
  pCursr->needRewind = 1;
  return SQLITE_OK;
}

/*
** Read the next key from the table.  Return 1 on success.  Return
** 0 if there are no more keys.
*/
static int sqliteGdbmNextKey(DbbeCursor *pCursr){
  datum nextkey;
  int rc;
  if( pCursr==0 || pCursr->pFile==0 || pCursr->pFile->dbf==0 ){
    pCursr->readPending = 0;
    return 0;
  }
  if( pCursr->needRewind ){
    nextkey = gdbm_firstkey(pCursr->pFile->dbf);
    pCursr->needRewind = 0;
  }else{
    nextkey = gdbm_nextkey(pCursr->pFile->dbf, pCursr->key);
  }
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  pCursr->key = nextkey;
  if( pCursr->key.dptr ){
    pCursr->readPending = 1;
    rc = 1;
  }else{
    pCursr->needRewind = 1;
    pCursr->readPending = 0;
    rc = 0;
  }
  return rc;
}

/*
** Get a new integer key.
*/
static int sqliteGdbmNew(DbbeCursor *pCursr){
  int iKey;
  datum key;
  int go = 1;
  int i;
  struct rc4 *pRc4;

  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return 1;
  pRc4 = &pCursr->pBe->rc4;
  while( go ){
    iKey = 0;
    for(i=0; i<4; i++){
      iKey = (iKey<<8) + rc4byte(pRc4);
    }
    if( iKey==0 ) continue;
    key.dptr = (char*)&iKey;
    key.dsize = 4;
    go = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return iKey;
}   

/*
** Write an entry into the table.  Overwrite any prior entry with the
** same key.
*/
static int
sqliteGdbmPut(DbbeCursor *pCursr, int nKey,char *pKey,int nData,char *pData){
  datum data, key;
  int rc;
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  data.dsize = nData;
  data.dptr = pData;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_store(pCursr->pFile->dbf, key, data, GDBM_REPLACE);
  if( rc ) rc = SQLITE_ERROR;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  return rc;
}

/*
** Remove an entry from a table, if the entry exists.
*/
static int sqliteGdbmDelete(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int rc;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_delete(pCursr->pFile->dbf, key);
  if( rc ) rc = SQLITE_ERROR;
  return rc;
}

/*
** Open a temporary file.  The file should be deleted when closed.
**
** Note that we can't use the old Unix trick of opening the file
** and then immediately unlinking the file.  That works great
** under Unix, but fails when we try to port to Windows.
*/
static int sqliteGdbmOpenTempFile(Dbbe *pDbbe, FILE **ppFile){
  char *zFile;         /* Full name of the temporary file */
  char zBuf[50];       /* Base name of the temporary file */
  int i;               /* Loop counter */
  int limit;           /* Prevent an infinite loop */
  int rc = SQLITE_OK;  /* Value returned by this function */
  Dbbex *pBe = (Dbbex*)pDbbe;

  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]==0 ) break;
  }
  if( i>=pBe->nTemp ){
    pBe->nTemp++;
    pBe->apTemp = sqliteRealloc(pBe->apTemp, pBe->nTemp*sizeof(FILE*) );
    pBe->azTemp = sqliteRealloc(pBe->azTemp, pBe->nTemp*sizeof(char*) );
  }
  if( pBe->apTemp==0 ){
    *ppFile = 0;
    return SQLITE_NOMEM;
  }
  limit = 4;
  zFile = 0;
  do{
    randomName(&pBe->rc4, zBuf, "/_temp_file_");
    sqliteFree(zFile);
    zFile = 0;
    sqliteSetString(&zFile, pBe->zDir, zBuf, 0);
  }while( access(zFile,0)==0 && limit-- >= 0 );
  *ppFile = pBe->apTemp[i] = fopen(zFile, "w+");
  if( pBe->apTemp[i]==0 ){
    rc = SQLITE_ERROR;
    sqliteFree(zFile);
    pBe->azTemp[i] = 0;
  }else{
    pBe->azTemp[i] = zFile;
  }
  return rc;
}

/*
** Close a temporary file opened using sqliteGdbmOpenTempFile()
*/
static void sqliteGdbmCloseTempFile(Dbbe *pDbbe, FILE *f){
  int i;
  Dbbex *pBe = (Dbbex*)pDbbe;
  for(i=0; i<pBe->nTemp; i++){
    if( pBe->apTemp[i]==f ){
      unlink(pBe->azTemp[i]);
      sqliteFree(pBe->azTemp[i]);
      pBe->apTemp[i] = 0;
      pBe->azTemp[i] = 0;
      break;
    }
  }
  fclose(f);
}


/*
** This routine opens a new database.  For the GDBM driver
** implemented here, the database name is the name of the directory
** containing all the files of the database.
**
** If successful, a pointer to the Dbbe structure is returned.
** If there are errors, an appropriate error message is left
** in *pzErrMsg and NULL is returned.
*/
Dbbe *sqliteGdbmOpen(
  const char *zName,     /* The name of the database */
  int writeFlag,         /* True if we will be writing to the database */
  int createFlag,        /* True to create database if it doesn't exist */
  char **pzErrMsg        /* Write error messages (if any) here */
){
  Dbbex *pNew;
  struct stat statbuf;
  char *zMaster;

  if( !writeFlag ) createFlag = 0;
  if( stat(zName, &statbuf)!=0 ){
    if( createFlag ) mkdir(zName, 0750);
    if( stat(zName, &statbuf)!=0 ){
      sqliteSetString(pzErrMsg, createFlag ? 
         "can't find or create directory \"" : "can't find directory \"",
         zName, "\"", 0);
      return 0;
    }
  }
  if( !S_ISDIR(statbuf.st_mode) ){
    sqliteSetString(pzErrMsg, "not a directory: \"", zName, "\"", 0);
    return 0;
  }
  if( access(zName, writeFlag ? (X_OK|W_OK|R_OK) : (X_OK|R_OK)) ){
    sqliteSetString(pzErrMsg, "access permission denied", 0);
    return 0;
  }
  zMaster = 0;
  sqliteSetString(&zMaster, zName, "/" MASTER_NAME ".tbl", 0);
  if( stat(zMaster, &statbuf)==0
   && access(zMaster, writeFlag ? (W_OK|R_OK) : R_OK)!=0 ){
    sqliteSetString(pzErrMsg, "access permission denied for ", zMaster, 0);
    sqliteFree(zMaster);
    return 0;
  }
  sqliteFree(zMaster);
  pNew = sqliteMalloc(sizeof(Dbbex) + strlen(zName) + 1);
  if( pNew==0 ){
    sqliteSetString(pzErrMsg, "out of memory", 0);
    return 0;
  }
  pNew->dbbe.Close = sqliteGdbmClose;
  pNew->dbbe.OpenCursor = sqliteGdbmOpenCursor;
  pNew->dbbe.DropTable = sqliteGdbmDropTable;
  pNew->dbbe.ReorganizeTable = sqliteGdbmReorganizeTable;
  pNew->dbbe.CloseCursor = sqliteGdbmCloseCursor;
  pNew->dbbe.Fetch = sqliteGdbmFetch;
  pNew->dbbe.Test = sqliteGdbmTest;
  pNew->dbbe.CopyKey = sqliteGdbmCopyKey;
  pNew->dbbe.CopyData = sqliteGdbmCopyData;
  pNew->dbbe.ReadKey = sqliteGdbmReadKey;
  pNew->dbbe.ReadData = sqliteGdbmReadData;
  pNew->dbbe.KeyLength = sqliteGdbmKeyLength;
  pNew->dbbe.DataLength = sqliteGdbmDataLength;
  pNew->dbbe.NextKey = sqliteGdbmNextKey;
  pNew->dbbe.Rewind = sqliteGdbmRewind;
  pNew->dbbe.New = sqliteGdbmNew;
  pNew->dbbe.Put = sqliteGdbmPut;
  pNew->dbbe.Delete = sqliteGdbmDelete;
  pNew->dbbe.OpenTempFile = sqliteGdbmOpenTempFile;
  pNew->dbbe.CloseTempFile = sqliteGdbmCloseTempFile;
  pNew->zDir = (char*)&pNew[1];
  strcpy(pNew->zDir, zName);
  pNew->write = writeFlag;
  pNew->pOpen = 0;
  time(&statbuf.st_ctime);
  rc4init(&pNew->rc4, (char*)&statbuf, sizeof(statbuf));
  return &pNew->dbbe;
}

Changes to src/main.c.

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**
*************************************************************************
** 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 1.20 2000/10/16 22:06:42 drh Exp $
*/
#include "sqliteInt.h"

/*
** This is the callback routine for the code that initializes the
** database.  Each callback contains text of a CREATE TABLE or
** CREATE INDEX statement that must be parsed to yield the internal
................................................................................
}

/*
** Close an existing SQLite database
*/
void sqlite_close(sqlite *db){
  int i;
  sqliteDbbeClose(db->pBe);
  for(i=0; i<N_HASH; i++){
    Table *pNext, *pList = db->apTblHash[i];
    db->apTblHash[i] = 0;
    while( pList ){
      pNext = pList->pHash;
      pList->pHash = 0;
      sqliteDeleteTable(db, pList);







|







 







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**
*************************************************************************
** 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 1.21 2000/10/19 01:49:02 drh Exp $
*/
#include "sqliteInt.h"

/*
** This is the callback routine for the code that initializes the
** database.  Each callback contains text of a CREATE TABLE or
** CREATE INDEX statement that must be parsed to yield the internal
................................................................................
}

/*
** Close an existing SQLite database
*/
void sqlite_close(sqlite *db){
  int i;
  db->pBe->Close(db->pBe);
  for(i=0; i<N_HASH; i++){
    Table *pNext, *pList = db->apTblHash[i];
    db->apTblHash[i] = 0;
    while( pList ){
      pNext = pList->pHash;
      pList->pHash = 0;
      sqliteDeleteTable(db, pList);

Changes to src/vdbe.c.

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....
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2428
** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.43 2000/10/16 22:06:43 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>
#include <ctype.h>

/*
** SQL is translated into a sequence of instructions to be
................................................................................
static void Cleanup(Vdbe *p){
  int i;
  PopStack(p, p->tos+1);
  sqliteFree(p->azColName);
  p->azColName = 0;
  for(i=0; i<p->nCursor; i++){
    if( p->aCsr[i].pCursor ){
      sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
      p->aCsr[i].pCursor = 0;
    }
  }
  sqliteFree(p->aCsr);
  p->aCsr = 0;
  p->nCursor = 0;
  for(i=0; i<p->nMem; i++){
................................................................................
    }
  }
  sqliteFree(p->aMem);
  p->aMem = 0;
  p->nMem = 0;
  for(i=0; i<p->nList; i++){
    if( p->apList[i] ){
      sqliteDbbeCloseTempFile(p->pBe, p->apList[i]);
      p->apList[i] = 0;
    }
  }
  sqliteFree(p->apList);
  p->apList = 0;
  p->nList = 0;
  for(i=0; i<p->nSort; i++){
................................................................................
  char **pzErrMsg,           /* Error msg written here */
  void *pBusyArg,            /* 1st argument to the busy callback */
  int (*xBusy)(void*,const char*,int)  /* Called when a file is busy */
){
  int pc;                    /* The program counter */
  Op *pOp;                   /* Current operation */
  int rc;                    /* Value to return */

  char zBuf[100];            /* Space to sprintf() and integer */

  p->tos = -1;
  rc = SQLITE_OK;
#ifdef MEMORY_DEBUG
  if( access("vdbe_trace",0)==0 ){
    p->trace = stderr;
................................................................................
        if( i>=p->nCursor ){
          int j;
          p->aCsr = sqliteRealloc( p->aCsr, (i+1)*sizeof(Cursor) );
          if( p->aCsr==0 ){ p->nCursor = 0; goto no_mem; }
          for(j=p->nCursor; j<=i; j++) p->aCsr[j].pCursor = 0;
          p->nCursor = i+1;
        }else if( p->aCsr[i].pCursor ){
          sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
        }
        do {
          rc = sqliteDbbeOpenCursor(p->pBe,pOp->p3,pOp->p2,&p->aCsr[i].pCursor);
          switch( rc ){
            case SQLITE_BUSY: {
              if( xBusy==0 || (*xBusy)(pBusyArg, pOp->p3, ++busy)==0 ){
                sqliteSetString(pzErrMsg,"table ", pOp->p3, " is locked", 0);
                busy = 0;
              }
              break;
................................................................................
      **
      ** Close a cursor previously opened as P1.  If P1 is not
      ** currently open, this instruction is a no-op.
      */
      case OP_Close: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
          p->aCsr[i].pCursor = 0;
        }
        break;
      }

      /* Opcode: Fetch P1 * *
      **
................................................................................
      */
      case OP_Fetch: {
        int i = pOp->p1;
        int tos = p->tos;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            sqliteDbbeFetch(p->aCsr[i].pCursor, sizeof(int), 
                           (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            sqliteDbbeFetch(p->aCsr[i].pCursor, p->aStack[tos].n, 
                           p->zStack[tos]);
          }
          p->nFetch++;
        }
        PopStack(p, 1);
        break;
      }
................................................................................
      case OP_Found: {
        int i = pOp->p1;
        int tos = p->tos;
        int alreadyExists = 0;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            alreadyExists = sqliteDbbeTest(p->aCsr[i].pCursor, sizeof(int), 
                                          (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            alreadyExists = sqliteDbbeTest(p->aCsr[i].pCursor,p->aStack[tos].n, 
                                           p->zStack[tos]);
          }
        }
        if( pOp->opcode==OP_Found ){
          if( alreadyExists ) pc = pOp->p2 - 1;
        }else{
          if( !alreadyExists ) pc = pOp->p2 - 1;
................................................................................
      */
      case OP_New: {
        int i = pOp->p1;
        int v;
        if( i<0 || i>=p->nCursor || p->aCsr[i].pCursor==0 ){
          v = 0;
        }else{
          v = sqliteDbbeNew(p->aCsr[i].pCursor);
        }
        NeedStack(p, p->tos+1);
        p->tos++;
        p->aStack[p->tos].i = v;
        p->aStack[p->tos].flags = STK_Int;
        break;
      }
................................................................................
            if( Stringify(p, nos) ) goto no_mem;
            nKey = p->aStack[nos].n;
            zKey = p->zStack[nos];
          }else{
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[nos].i;
          }
          sqliteDbbePut(p->aCsr[i].pCursor, nKey, zKey,
                        p->aStack[tos].n, p->zStack[tos]);
        }
        PopStack(p, 2);
        break;
      }

      /* Opcode: Delete P1 * *
................................................................................
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[tos].i;
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            nKey = p->aStack[tos].n;
            zKey = p->zStack[tos];
          }
          sqliteDbbeDelete(p->aCsr[i].pCursor, nKey, zKey);
        }
        PopStack(p, 1);
        break;
      }

      /* Opcode: KeyAsData P1 P2 *
      **
................................................................................
        int tos = ++p->tos;
        DbbeCursor *pCrsr;
        char *z;

        if( NeedStack(p, tos) ) goto no_mem;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          if( p->aCsr[i].keyAsData ){
            amt = sqliteDbbeKeyLength(pCrsr);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)sqliteDbbeReadKey(pCrsr, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = sqliteDbbeReadKey(pCrsr, *pAddr);
          }else{
            amt = sqliteDbbeDataLength(pCrsr);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)sqliteDbbeReadData(pCrsr, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = sqliteDbbeReadData(pCrsr, *pAddr);
          }
          p->zStack[tos] = z;
          p->aStack[tos].n = strlen(z) + 1;
          p->aStack[tos].flags = STK_Str;
        }
        break;
      }
................................................................................
      case OP_Key: {
        int i = pOp->p1;
        int tos = ++p->tos;
        DbbeCursor *pCrsr;

        if( NeedStack(p, p->tos) ) goto no_mem;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          char *z = sqliteDbbeReadKey(pCrsr, 0);
          if( p->aCsr[i].keyAsData ){
            p->zStack[tos] = z;
            p->aStack[tos].flags = STK_Str;
            p->aStack[tos].n = sqliteDbbeKeyLength(pCrsr);
          }else{
            memcpy(&p->aStack[tos].i, z, sizeof(int));
            p->aStack[tos].flags = STK_Int;
          }
        }
        break;
      }
................................................................................
      **
      ** The next use of the Key or Field or Next instruction for P1 
      ** will refer to the first entry in the database file.
      */
      case OP_Rewind: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          sqliteDbbeRewind(p->aCsr[i].pCursor);
        }
        break;
      }

      /* Opcode: Next P1 P2 *
      **
      ** Advance P1 to the next key/data pair in the file.  Or, if there are no
      ** more key/data pairs, rewind P1 and jump to location P2.
      */
      case OP_Next: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          if( sqliteDbbeNextKey(p->aCsr[i].pCursor)==0 ){
            pc = pOp->p2 - 1;
          }else{
            p->nFetch++;
          }
        }
        break;
      }
................................................................................

        if( NeedStack(p, p->tos) ) goto no_mem;
        p->zStack[tos] = 0;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int *aIdx;
          int nIdx;
          int j, k;
          nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
          aIdx = (int*)sqliteDbbeReadData(pCrsr, 0);
          if( nIdx>1 ){
            k = *(aIdx++);
            if( k>nIdx-1 ) k = nIdx-1;
          }else{
            k = nIdx;
          }
          for(j=p->aCsr[i].index; j<k; j++){
................................................................................
        if( nos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int r;
          int newVal;
          Integerify(p, nos);
          newVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = sqliteDbbeFetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ){
            /* Create a new record for this index */
            sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                          sizeof(int), (char*)&newVal);
          }else{
            /* Extend the existing record */
            int nIdx;
            int *aIdx;
            int k;
            
            nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
            if( nIdx==1 ){
              aIdx = sqliteMalloc( sizeof(int)*4 );
              if( aIdx==0 ) goto no_mem;
              aIdx[0] = 2;
              sqliteDbbeCopyData(pCrsr, 0, sizeof(int), (char*)&aIdx[1]);
              aIdx[2] = newVal;
              sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                    sizeof(int)*4, (char*)aIdx);
              sqliteFree(aIdx);
            }else{
              aIdx = (int*)sqliteDbbeReadData(pCrsr, 0);
              k = aIdx[0];
              if( k<nIdx-1 ){
                aIdx[k+1] = newVal;
                aIdx[0]++;
                sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                    sizeof(int)*nIdx, (char*)aIdx);
              }else{
                nIdx *= 2;
                aIdx = sqliteMalloc( sizeof(int)*nIdx );
                if( aIdx==0 ) goto no_mem;
                sqliteDbbeCopyData(pCrsr, 0, sizeof(int)*(k+1), (char*)aIdx);
                aIdx[k+1] = newVal;
                aIdx[0]++;
                sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                      sizeof(int)*nIdx, (char*)aIdx);
                sqliteFree(aIdx);
              }
            }              
          }
        }
        PopStack(p, 2);
................................................................................
          int nIdx;
          int j, k;
          int r;
          int oldVal;
          Integerify(p, nos);
          oldVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = sqliteDbbeFetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ) break;
          nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
          aIdx = (int*)sqliteDbbeReadData(pCrsr, 0);
          if( (nIdx==1 && aIdx[0]==oldVal) || (aIdx[0]==1 && aIdx[1]==oldVal) ){
            sqliteDbbeDelete(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          }else{
            k = aIdx[0];
            for(j=1; j<=k && aIdx[j]!=oldVal; j++){}
            if( j>k ) break;
            aIdx[j] = aIdx[k];
            aIdx[k] = 0;
            aIdx[0]--;
            if( aIdx[0]*3 + 1 < nIdx ){
              nIdx /= 2;
            }
            sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos], 
                          sizeof(int)*nIdx, (char*)aIdx);
          }
        }
        PopStack(p, 2);
        break;
      }

................................................................................
      /* Opcode: Destroy * * P3
      **
      ** Drop the disk file whose name is P3.  All key/data pairs in
      ** the file are deleted and the file itself is removed
      ** from the disk.
      */
      case OP_Destroy: {
        sqliteDbbeDropTable(p->pBe, pOp->p3);
        break;
      }

      /* Opcode: Reorganize * * P3
      **
      ** Compress, optimize, and tidy up the GDBM file named by P3.
      */
      case OP_Reorganize: {
        sqliteDbbeReorganizeTable(p->pBe, pOp->p3);
        break;
      }

      /* Opcode: ListOpen P1 * *
      **
      ** Open a file used for temporary storage of integer table keys.  P1
      ** will server as a handle to this temporary file for future
................................................................................
        if( i>=p->nList ){
          int j;
          p->apList = sqliteRealloc( p->apList, (i+1)*sizeof(FILE*) );
          if( p->apList==0 ){ p->nList = 0; goto no_mem; }
          for(j=p->nList; j<=i; j++) p->apList[j] = 0;
          p->nList = i+1;
        }else if( p->apList[i] ){
          sqliteDbbeCloseTempFile(p->pBe, p->apList[i]);
        }
        rc = sqliteDbbeOpenTempFile(p->pBe, &p->apList[i]);
        if( rc!=SQLITE_OK ){
          sqliteSetString(pzErrMsg, "unable to open a temporary file", 0);
        }
        break;
      }

      /* Opcode: ListWrite P1 * *
................................................................................
      **
      ** Close the temporary storage buffer and discard its contents.
      */
      case OP_ListClose: {
        int i = pOp->p1;
        if( i<0 ) goto bad_instruction;
        if( i<p->nList && p->apList[i]!=0 ){
          sqliteDbbeCloseTempFile(p->pBe, p->apList[i]);
          p->apList[i] = 0;
        }
        break;
      }

      /* Opcode: SortOpen P1 * *
      **







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38
39
40
41
42
43
44
45
46
47
48
49
50
51
...
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
...
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
...
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
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1828
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....
1917
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1929
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1931
....
1950
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....
1977
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1991
....
2031
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....
2076
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2080
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2086
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2088
2089
2090
2091
2092
2093
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....
2097
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2100
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2102
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2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
....
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
....
2206
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2209
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2250
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2255
2256
....
2281
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2300
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....
2312
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2321
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2325
2326
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2330
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....
2343
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....
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2429
** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.44 2000/10/19 01:49:03 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>
#include <ctype.h>

/*
** SQL is translated into a sequence of instructions to be
................................................................................
static void Cleanup(Vdbe *p){
  int i;
  PopStack(p, p->tos+1);
  sqliteFree(p->azColName);
  p->azColName = 0;
  for(i=0; i<p->nCursor; i++){
    if( p->aCsr[i].pCursor ){
      p->pBe->CloseCursor(p->aCsr[i].pCursor);
      p->aCsr[i].pCursor = 0;
    }
  }
  sqliteFree(p->aCsr);
  p->aCsr = 0;
  p->nCursor = 0;
  for(i=0; i<p->nMem; i++){
................................................................................
    }
  }
  sqliteFree(p->aMem);
  p->aMem = 0;
  p->nMem = 0;
  for(i=0; i<p->nList; i++){
    if( p->apList[i] ){
      p->pBe->CloseTempFile(p->pBe, p->apList[i]);
      p->apList[i] = 0;
    }
  }
  sqliteFree(p->apList);
  p->apList = 0;
  p->nList = 0;
  for(i=0; i<p->nSort; i++){
................................................................................
  char **pzErrMsg,           /* Error msg written here */
  void *pBusyArg,            /* 1st argument to the busy callback */
  int (*xBusy)(void*,const char*,int)  /* Called when a file is busy */
){
  int pc;                    /* The program counter */
  Op *pOp;                   /* Current operation */
  int rc;                    /* Value to return */
  Dbbe *pBe = p->pBe;        /* The backend driver */
  char zBuf[100];            /* Space to sprintf() and integer */

  p->tos = -1;
  rc = SQLITE_OK;
#ifdef MEMORY_DEBUG
  if( access("vdbe_trace",0)==0 ){
    p->trace = stderr;
................................................................................
        if( i>=p->nCursor ){
          int j;
          p->aCsr = sqliteRealloc( p->aCsr, (i+1)*sizeof(Cursor) );
          if( p->aCsr==0 ){ p->nCursor = 0; goto no_mem; }
          for(j=p->nCursor; j<=i; j++) p->aCsr[j].pCursor = 0;
          p->nCursor = i+1;
        }else if( p->aCsr[i].pCursor ){
          pBe->CloseCursor(p->aCsr[i].pCursor);
        }
        do {
          rc = pBe->OpenCursor(pBe,pOp->p3,pOp->p2,&p->aCsr[i].pCursor);
          switch( rc ){
            case SQLITE_BUSY: {
              if( xBusy==0 || (*xBusy)(pBusyArg, pOp->p3, ++busy)==0 ){
                sqliteSetString(pzErrMsg,"table ", pOp->p3, " is locked", 0);
                busy = 0;
              }
              break;
................................................................................
      **
      ** Close a cursor previously opened as P1.  If P1 is not
      ** currently open, this instruction is a no-op.
      */
      case OP_Close: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          pBe->CloseCursor(p->aCsr[i].pCursor);
          p->aCsr[i].pCursor = 0;
        }
        break;
      }

      /* Opcode: Fetch P1 * *
      **
................................................................................
      */
      case OP_Fetch: {
        int i = pOp->p1;
        int tos = p->tos;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            pBe->Fetch(p->aCsr[i].pCursor, sizeof(int), 
                           (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            pBe->Fetch(p->aCsr[i].pCursor, p->aStack[tos].n, 
                           p->zStack[tos]);
          }
          p->nFetch++;
        }
        PopStack(p, 1);
        break;
      }
................................................................................
      case OP_Found: {
        int i = pOp->p1;
        int tos = p->tos;
        int alreadyExists = 0;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            alreadyExists = pBe->Test(p->aCsr[i].pCursor, sizeof(int), 
                                          (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            alreadyExists = pBe->Test(p->aCsr[i].pCursor,p->aStack[tos].n, 
                                           p->zStack[tos]);
          }
        }
        if( pOp->opcode==OP_Found ){
          if( alreadyExists ) pc = pOp->p2 - 1;
        }else{
          if( !alreadyExists ) pc = pOp->p2 - 1;
................................................................................
      */
      case OP_New: {
        int i = pOp->p1;
        int v;
        if( i<0 || i>=p->nCursor || p->aCsr[i].pCursor==0 ){
          v = 0;
        }else{
          v = pBe->New(p->aCsr[i].pCursor);
        }
        NeedStack(p, p->tos+1);
        p->tos++;
        p->aStack[p->tos].i = v;
        p->aStack[p->tos].flags = STK_Int;
        break;
      }
................................................................................
            if( Stringify(p, nos) ) goto no_mem;
            nKey = p->aStack[nos].n;
            zKey = p->zStack[nos];
          }else{
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[nos].i;
          }
          pBe->Put(p->aCsr[i].pCursor, nKey, zKey,
                        p->aStack[tos].n, p->zStack[tos]);
        }
        PopStack(p, 2);
        break;
      }

      /* Opcode: Delete P1 * *
................................................................................
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[tos].i;
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            nKey = p->aStack[tos].n;
            zKey = p->zStack[tos];
          }
          pBe->Delete(p->aCsr[i].pCursor, nKey, zKey);
        }
        PopStack(p, 1);
        break;
      }

      /* Opcode: KeyAsData P1 P2 *
      **
................................................................................
        int tos = ++p->tos;
        DbbeCursor *pCrsr;
        char *z;

        if( NeedStack(p, tos) ) goto no_mem;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          if( p->aCsr[i].keyAsData ){
            amt = pBe->KeyLength(pCrsr);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)pBe->ReadKey(pCrsr, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = pBe->ReadKey(pCrsr, *pAddr);
          }else{
            amt = pBe->DataLength(pCrsr);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)pBe->ReadData(pCrsr, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = pBe->ReadData(pCrsr, *pAddr);
          }
          p->zStack[tos] = z;
          p->aStack[tos].n = strlen(z) + 1;
          p->aStack[tos].flags = STK_Str;
        }
        break;
      }
................................................................................
      case OP_Key: {
        int i = pOp->p1;
        int tos = ++p->tos;
        DbbeCursor *pCrsr;

        if( NeedStack(p, p->tos) ) goto no_mem;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          char *z = pBe->ReadKey(pCrsr, 0);
          if( p->aCsr[i].keyAsData ){
            p->zStack[tos] = z;
            p->aStack[tos].flags = STK_Str;
            p->aStack[tos].n = pBe->KeyLength(pCrsr);
          }else{
            memcpy(&p->aStack[tos].i, z, sizeof(int));
            p->aStack[tos].flags = STK_Int;
          }
        }
        break;
      }
................................................................................
      **
      ** The next use of the Key or Field or Next instruction for P1 
      ** will refer to the first entry in the database file.
      */
      case OP_Rewind: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          pBe->Rewind(p->aCsr[i].pCursor);
        }
        break;
      }

      /* Opcode: Next P1 P2 *
      **
      ** Advance P1 to the next key/data pair in the file.  Or, if there are no
      ** more key/data pairs, rewind P1 and jump to location P2.
      */
      case OP_Next: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          if( pBe->NextKey(p->aCsr[i].pCursor)==0 ){
            pc = pOp->p2 - 1;
          }else{
            p->nFetch++;
          }
        }
        break;
      }
................................................................................

        if( NeedStack(p, p->tos) ) goto no_mem;
        p->zStack[tos] = 0;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int *aIdx;
          int nIdx;
          int j, k;
          nIdx = pBe->DataLength(pCrsr)/sizeof(int);
          aIdx = (int*)pBe->ReadData(pCrsr, 0);
          if( nIdx>1 ){
            k = *(aIdx++);
            if( k>nIdx-1 ) k = nIdx-1;
          }else{
            k = nIdx;
          }
          for(j=p->aCsr[i].index; j<k; j++){
................................................................................
        if( nos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int r;
          int newVal;
          Integerify(p, nos);
          newVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = pBe->Fetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ){
            /* Create a new record for this index */
            pBe->Put(pCrsr, p->aStack[tos].n, p->zStack[tos],
                          sizeof(int), (char*)&newVal);
          }else{
            /* Extend the existing record */
            int nIdx;
            int *aIdx;
            int k;
            
            nIdx = pBe->DataLength(pCrsr)/sizeof(int);
            if( nIdx==1 ){
              aIdx = sqliteMalloc( sizeof(int)*4 );
              if( aIdx==0 ) goto no_mem;
              aIdx[0] = 2;
              pBe->CopyData(pCrsr, 0, sizeof(int), (char*)&aIdx[1]);
              aIdx[2] = newVal;
              pBe->Put(pCrsr, p->aStack[tos].n, p->zStack[tos],
                    sizeof(int)*4, (char*)aIdx);
              sqliteFree(aIdx);
            }else{
              aIdx = (int*)pBe->ReadData(pCrsr, 0);
              k = aIdx[0];
              if( k<nIdx-1 ){
                aIdx[k+1] = newVal;
                aIdx[0]++;
                pBe->Put(pCrsr, p->aStack[tos].n, p->zStack[tos],
                    sizeof(int)*nIdx, (char*)aIdx);
              }else{
                nIdx *= 2;
                aIdx = sqliteMalloc( sizeof(int)*nIdx );
                if( aIdx==0 ) goto no_mem;
                pBe->CopyData(pCrsr, 0, sizeof(int)*(k+1), (char*)aIdx);
                aIdx[k+1] = newVal;
                aIdx[0]++;
                pBe->Put(pCrsr, p->aStack[tos].n, p->zStack[tos],
                      sizeof(int)*nIdx, (char*)aIdx);
                sqliteFree(aIdx);
              }
            }              
          }
        }
        PopStack(p, 2);
................................................................................
          int nIdx;
          int j, k;
          int r;
          int oldVal;
          Integerify(p, nos);
          oldVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = pBe->Fetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ) break;
          nIdx = pBe->DataLength(pCrsr)/sizeof(int);
          aIdx = (int*)pBe->ReadData(pCrsr, 0);
          if( (nIdx==1 && aIdx[0]==oldVal) || (aIdx[0]==1 && aIdx[1]==oldVal) ){
            pBe->Delete(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          }else{
            k = aIdx[0];
            for(j=1; j<=k && aIdx[j]!=oldVal; j++){}
            if( j>k ) break;
            aIdx[j] = aIdx[k];
            aIdx[k] = 0;
            aIdx[0]--;
            if( aIdx[0]*3 + 1 < nIdx ){
              nIdx /= 2;
            }
            pBe->Put(pCrsr, p->aStack[tos].n, p->zStack[tos], 
                          sizeof(int)*nIdx, (char*)aIdx);
          }
        }
        PopStack(p, 2);
        break;
      }

................................................................................
      /* Opcode: Destroy * * P3
      **
      ** Drop the disk file whose name is P3.  All key/data pairs in
      ** the file are deleted and the file itself is removed
      ** from the disk.
      */
      case OP_Destroy: {
        pBe->DropTable(pBe, pOp->p3);
        break;
      }

      /* Opcode: Reorganize * * P3
      **
      ** Compress, optimize, and tidy up the GDBM file named by P3.
      */
      case OP_Reorganize: {
        pBe->ReorganizeTable(pBe, pOp->p3);
        break;
      }

      /* Opcode: ListOpen P1 * *
      **
      ** Open a file used for temporary storage of integer table keys.  P1
      ** will server as a handle to this temporary file for future
................................................................................
        if( i>=p->nList ){
          int j;
          p->apList = sqliteRealloc( p->apList, (i+1)*sizeof(FILE*) );
          if( p->apList==0 ){ p->nList = 0; goto no_mem; }
          for(j=p->nList; j<=i; j++) p->apList[j] = 0;
          p->nList = i+1;
        }else if( p->apList[i] ){
          pBe->CloseTempFile(pBe, p->apList[i]);
        }
        rc = pBe->OpenTempFile(pBe, &p->apList[i]);
        if( rc!=SQLITE_OK ){
          sqliteSetString(pzErrMsg, "unable to open a temporary file", 0);
        }
        break;
      }

      /* Opcode: ListWrite P1 * *
................................................................................
      **
      ** Close the temporary storage buffer and discard its contents.
      */
      case OP_ListClose: {
        int i = pOp->p1;
        if( i<0 ) goto bad_instruction;
        if( i<p->nList && p->apList[i]!=0 ){
          pBe->CloseTempFile(pBe, p->apList[i]);
          p->apList[i] = 0;
        }
        break;
      }

      /* Opcode: SortOpen P1 * *
      **

Changes to www/changes.tcl.

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}


proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}








chng {2000 Oct 16 (1.0.12)} {
<li>Fixed an off-by-one error that was causing a coredump in 
    the '%q' format directive of the new
    <b>sqlite_..._printf()</b> routines.</li>
<li>Added the <b>sqlite_interrupt()</b> interface.</li>
<li>In the shell, <b>sqlite_interrupt()</b> is invoked when the







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>







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}


proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}

chng {2000 Oct 18 (1.0.13)} {
<li>Break out the GDBM driver into a separate file in anticipation
    to added new drivers.</li>
<li>Allow the name of a database to be prefixed by the driver type.
    For now, the only driver type is "gdbm:".<li>
}

chng {2000 Oct 16 (1.0.12)} {
<li>Fixed an off-by-one error that was causing a coredump in 
    the '%q' format directive of the new
    <b>sqlite_..._printf()</b> routines.</li>
<li>Added the <b>sqlite_interrupt()</b> interface.</li>
<li>In the shell, <b>sqlite_interrupt()</b> is invoked when the