root/third_party/sqlite/src/src/tclsqlite.c

DEFINITIONS

1. strlen30
2. closeIncrblobChannels
3. incrblobClose
4. incrblobInput
5. incrblobOutput
6. incrblobSeek
7. incrblobWatch
8. incrblobHandle
9. createIncrblobChannel
10. safeToUseEvalObjv
11. findSqlFunc
12. flushStmtCache
13. DbDeleteCmd
14. DbBusyHandler
15. DbProgressHandler
16. DbTraceHandler
17. DbProfileHandler
18. DbCommitHandler
19. DbRollbackHandler
20. DbWalHandler
21. setTestUnlockNotifyVars
22. DbUnlockNotify
23. DbUpdateHandler
24. tclCollateNeeded
25. tclSqlCollate
26. tclSqlFunc
27. auth_callback
28. dbTextToObj
29. local_getline
30. DbTransPostCmd
31. dbPrepareAndBind
32. dbReleaseStmt
33. dbReleaseColumnNames
34. dbEvalInit
35. dbEvalRowInfo
36. dbEvalStep
37. dbEvalFinalize
38. dbEvalColumnValue
39. DbUseNre
40. DbEvalNextCmd
41. DbObjCmd
42. DbObjCmdAdaptor
43. DbMain
44. Sqlite3_Init
45. Tclsqlite3_Init
46. Sqlite3_SafeInit
47. Tclsqlite3_SafeInit
48. Sqlite3_Unload
49. Tclsqlite3_Unload
50. Sqlite3_SafeUnload
51. Tclsqlite3_SafeUnload
52. Sqlite_Init
53. Tclsqlite_Init
54. Sqlite_SafeInit
55. Tclsqlite_SafeInit
56. Sqlite_Unload
57. Tclsqlite_Unload
58. Sqlite_SafeUnload
59. Tclsqlite_SafeUnload
60. byteReverse
61. MD5Transform
62. MD5Init
63. MD5Update
64. MD5Final
65. MD5DigestToBase16
66. MD5DigestToBase10x8
67. md5_cmd
68. md5file_cmd
69. Md5_Init
70. md5step
71. md5finalize
72. Md5_Register
73. init_all_cmd
74. init_all
75. TCLSH_MAIN

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** A TCL Interface to SQLite.  Append this file to sqlite3.c and
** compile the whole thing to build a TCL-enabled version of SQLite.
**
** Compile-time options:
**
**  -DTCLSH=1             Add a "main()" routine that works as a tclsh.
**
**  -DSQLITE_TCLMD5       When used in conjuction with -DTCLSH=1, add
**                        four new commands to the TCL interpreter for
**                        generating MD5 checksums:  md5, md5file,
**                        md5-10x8, and md5file-10x8.
**
**  -DSQLITE_TEST         When used in conjuction with -DTCLSH=1, add
**                        hundreds of new commands used for testing
**                        SQLite.  This option implies -DSQLITE_TCLMD5.
*/
#include "tcl.h"
#include <errno.h>

/*
** Some additional include files are needed if this file is not
** appended to the amalgamation.
*/
#ifndef SQLITE_AMALGAMATION
# include "sqlite3.h"
# include <stdlib.h>
# include <string.h>
# include <assert.h>
  typedef unsigned char u8;
#endif
#include <ctype.h>

/*
 * Windows needs to know which symbols to export.  Unix does not.
 * BUILD_sqlite should be undefined for Unix.
 */
#ifdef BUILD_sqlite
#undef TCL_STORAGE_CLASS
#define TCL_STORAGE_CLASS DLLEXPORT
#endif /* BUILD_sqlite */

#define NUM_PREPARED_STMTS 10
#define MAX_PREPARED_STMTS 100

/*
** If TCL uses UTF-8 and SQLite is configured to use iso8859, then we
** have to do a translation when going between the two.  Set the 
** UTF_TRANSLATION_NEEDED macro to indicate that we need to do
** this translation.  
*/
#if defined(TCL_UTF_MAX) && !defined(SQLITE_UTF8)
# define UTF_TRANSLATION_NEEDED 1
#endif

/*
** New SQL functions can be created as TCL scripts.  Each such function
** is described by an instance of the following structure.
*/
typedef struct SqlFunc SqlFunc;
struct SqlFunc {
  Tcl_Interp *interp;   /* The TCL interpret to execute the function */
  Tcl_Obj *pScript;     /* The Tcl_Obj representation of the script */
  int useEvalObjv;      /* True if it is safe to use Tcl_EvalObjv */
  char *zName;          /* Name of this function */
  SqlFunc *pNext;       /* Next function on the list of them all */
};

/*
** New collation sequences function can be created as TCL scripts.  Each such
** function is described by an instance of the following structure.
*/
typedef struct SqlCollate SqlCollate;
struct SqlCollate {
  Tcl_Interp *interp;   /* The TCL interpret to execute the function */
  char *zScript;        /* The script to be run */
  SqlCollate *pNext;    /* Next function on the list of them all */
};

/*
** Prepared statements are cached for faster execution.  Each prepared
** statement is described by an instance of the following structure.
*/
typedef struct SqlPreparedStmt SqlPreparedStmt;
struct SqlPreparedStmt {
  SqlPreparedStmt *pNext;  /* Next in linked list */
  SqlPreparedStmt *pPrev;  /* Previous on the list */
  sqlite3_stmt *pStmt;     /* The prepared statement */
  int nSql;                /* chars in zSql[] */
  const char *zSql;        /* Text of the SQL statement */
  int nParm;               /* Size of apParm array */
  Tcl_Obj **apParm;        /* Array of referenced object pointers */
};

typedef struct IncrblobChannel IncrblobChannel;

/*
** There is one instance of this structure for each SQLite database
** that has been opened by the SQLite TCL interface.
*/
typedef struct SqliteDb SqliteDb;
struct SqliteDb {
  sqlite3 *db;               /* The "real" database structure. MUST BE FIRST */
  Tcl_Interp *interp;        /* The interpreter used for this database */
  char *zBusy;               /* The busy callback routine */
  char *zCommit;             /* The commit hook callback routine */
  char *zTrace;              /* The trace callback routine */
  char *zProfile;            /* The profile callback routine */
  char *zProgress;           /* The progress callback routine */
  char *zAuth;               /* The authorization callback routine */
  int disableAuth;           /* Disable the authorizer if it exists */
  char *zNull;               /* Text to substitute for an SQL NULL value */
  SqlFunc *pFunc;            /* List of SQL functions */
  Tcl_Obj *pUpdateHook;      /* Update hook script (if any) */
  Tcl_Obj *pRollbackHook;    /* Rollback hook script (if any) */
  Tcl_Obj *pWalHook;         /* WAL hook script (if any) */
  Tcl_Obj *pUnlockNotify;    /* Unlock notify script (if any) */
  SqlCollate *pCollate;      /* List of SQL collation functions */
  int rc;                    /* Return code of most recent sqlite3_exec() */
  Tcl_Obj *pCollateNeeded;   /* Collation needed script */
  SqlPreparedStmt *stmtList; /* List of prepared statements*/
  SqlPreparedStmt *stmtLast; /* Last statement in the list */
  int maxStmt;               /* The next maximum number of stmtList */
  int nStmt;                 /* Number of statements in stmtList */
  IncrblobChannel *pIncrblob;/* Linked list of open incrblob channels */
  int nStep, nSort, nIndex;  /* Statistics for most recent operation */
  int nTransaction;          /* Number of nested [transaction] methods */
};

struct IncrblobChannel {
  sqlite3_blob *pBlob;      /* sqlite3 blob handle */
  SqliteDb *pDb;            /* Associated database connection */
  int iSeek;                /* Current seek offset */
  Tcl_Channel channel;      /* Channel identifier */
  IncrblobChannel *pNext;   /* Linked list of all open incrblob channels */
  IncrblobChannel *pPrev;   /* Linked list of all open incrblob channels */
};

/*
** Compute a string length that is limited to what can be stored in
** lower 30 bits of a 32-bit signed integer.
*/
static int strlen30(const char *z){
  const char *z2 = z;
  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}


#ifndef SQLITE_OMIT_INCRBLOB
/*
** Close all incrblob channels opened using database connection pDb.
** This is called when shutting down the database connection.
*/
static void closeIncrblobChannels(SqliteDb *pDb){
  IncrblobChannel *p;
  IncrblobChannel *pNext;

  for(p=pDb->pIncrblob; p; p=pNext){
    pNext = p->pNext;

    /* Note: Calling unregister here call Tcl_Close on the incrblob channel, 
    ** which deletes the IncrblobChannel structure at *p. So do not
    ** call Tcl_Free() here.
    */
    Tcl_UnregisterChannel(pDb->interp, p->channel);
  }
}

/*
** Close an incremental blob channel.
*/
static int incrblobClose(ClientData instanceData, Tcl_Interp *interp){
  IncrblobChannel *p = (IncrblobChannel *)instanceData;
  int rc = sqlite3_blob_close(p->pBlob);
  sqlite3 *db = p->pDb->db;

  /* Remove the channel from the SqliteDb.pIncrblob list. */
  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }
  if( p->pDb->pIncrblob==p ){
    p->pDb->pIncrblob = p->pNext;
  }

  /* Free the IncrblobChannel structure */
  Tcl_Free((char *)p);

  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)sqlite3_errmsg(db), TCL_VOLATILE);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Read data from an incremental blob channel.
*/
static int incrblobInput(
  ClientData instanceData, 
  char *buf, 
  int bufSize,
  int *errorCodePtr
){
  IncrblobChannel *p = (IncrblobChannel *)instanceData;
  int nRead = bufSize;         /* Number of bytes to read */
  int nBlob;                   /* Total size of the blob */
  int rc;                      /* sqlite error code */

  nBlob = sqlite3_blob_bytes(p->pBlob);
  if( (p->iSeek+nRead)>nBlob ){
    nRead = nBlob-p->iSeek;
  }
  if( nRead<=0 ){
    return 0;
  }

  rc = sqlite3_blob_read(p->pBlob, (void *)buf, nRead, p->iSeek);
  if( rc!=SQLITE_OK ){
    *errorCodePtr = rc;
    return -1;
  }

  p->iSeek += nRead;
  return nRead;
}

/*
** Write data to an incremental blob channel.
*/
static int incrblobOutput(
  ClientData instanceData, 
  CONST char *buf, 
  int toWrite,
  int *errorCodePtr
){
  IncrblobChannel *p = (IncrblobChannel *)instanceData;
  int nWrite = toWrite;        /* Number of bytes to write */
  int nBlob;                   /* Total size of the blob */
  int rc;                      /* sqlite error code */

  nBlob = sqlite3_blob_bytes(p->pBlob);
  if( (p->iSeek+nWrite)>nBlob ){
    *errorCodePtr = EINVAL;
    return -1;
  }
  if( nWrite<=0 ){
    return 0;
  }

  rc = sqlite3_blob_write(p->pBlob, (void *)buf, nWrite, p->iSeek);
  if( rc!=SQLITE_OK ){
    *errorCodePtr = EIO;
    return -1;
  }

  p->iSeek += nWrite;
  return nWrite;
}

/*
** Seek an incremental blob channel.
*/
static int incrblobSeek(
  ClientData instanceData, 
  long offset,
  int seekMode,
  int *errorCodePtr
){
  IncrblobChannel *p = (IncrblobChannel *)instanceData;

  switch( seekMode ){
    case SEEK_SET:
      p->iSeek = offset;
      break;
    case SEEK_CUR:
      p->iSeek += offset;
      break;
    case SEEK_END:
      p->iSeek = sqlite3_blob_bytes(p->pBlob) + offset;
      break;

    default: assert(!"Bad seekMode");
  }

  return p->iSeek;
}


static void incrblobWatch(ClientData instanceData, int mode){ 
  /* NO-OP */ 
}
static int incrblobHandle(ClientData instanceData, int dir, ClientData *hPtr){
  return TCL_ERROR;
}

static Tcl_ChannelType IncrblobChannelType = {
  "incrblob",                        /* typeName                             */
  TCL_CHANNEL_VERSION_2,             /* version                              */
  incrblobClose,                     /* closeProc                            */
  incrblobInput,                     /* inputProc                            */
  incrblobOutput,                    /* outputProc                           */
  incrblobSeek,                      /* seekProc                             */
  0,                                 /* setOptionProc                        */
  0,                                 /* getOptionProc                        */
  incrblobWatch,                     /* watchProc (this is a no-op)          */
  incrblobHandle,                    /* getHandleProc (always returns error) */
  0,                                 /* close2Proc                           */
  0,                                 /* blockModeProc                        */
  0,                                 /* flushProc                            */
  0,                                 /* handlerProc                          */
  0,                                 /* wideSeekProc                         */
};

/*
** Create a new incrblob channel.
*/
static int createIncrblobChannel(
  Tcl_Interp *interp, 
  SqliteDb *pDb, 
  const char *zDb,
  const char *zTable, 
  const char *zColumn, 
  sqlite_int64 iRow,
  int isReadonly
){
  IncrblobChannel *p;
  sqlite3 *db = pDb->db;
  sqlite3_blob *pBlob;
  int rc;
  int flags = TCL_READABLE|(isReadonly ? 0 : TCL_WRITABLE);

  /* This variable is used to name the channels: "incrblob_[incr count]" */
  static int count = 0;
  char zChannel[64];

  rc = sqlite3_blob_open(db, zDb, zTable, zColumn, iRow, !isReadonly, &pBlob);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)sqlite3_errmsg(pDb->db), TCL_VOLATILE);
    return TCL_ERROR;
  }

  p = (IncrblobChannel *)Tcl_Alloc(sizeof(IncrblobChannel));
  p->iSeek = 0;
  p->pBlob = pBlob;

  sqlite3_snprintf(sizeof(zChannel), zChannel, "incrblob_%d", ++count);
  p->channel = Tcl_CreateChannel(&IncrblobChannelType, zChannel, p, flags);
  Tcl_RegisterChannel(interp, p->channel);

  /* Link the new channel into the SqliteDb.pIncrblob list. */
  p->pNext = pDb->pIncrblob;
  p->pPrev = 0;
  if( p->pNext ){
    p->pNext->pPrev = p;
  }
  pDb->pIncrblob = p;
  p->pDb = pDb;

  Tcl_SetResult(interp, (char *)Tcl_GetChannelName(p->channel), TCL_VOLATILE);
  return TCL_OK;
}
#else  /* else clause for "#ifndef SQLITE_OMIT_INCRBLOB" */
  #define closeIncrblobChannels(pDb)
#endif

/*
** Look at the script prefix in pCmd.  We will be executing this script
** after first appending one or more arguments.  This routine analyzes
** the script to see if it is safe to use Tcl_EvalObjv() on the script
** rather than the more general Tcl_EvalEx().  Tcl_EvalObjv() is much
** faster.
**
** Scripts that are safe to use with Tcl_EvalObjv() consists of a
** command name followed by zero or more arguments with no [...] or $
** or {...} or ; to be seen anywhere.  Most callback scripts consist
** of just a single procedure name and they meet this requirement.
*/
static int safeToUseEvalObjv(Tcl_Interp *interp, Tcl_Obj *pCmd){
  /* We could try to do something with Tcl_Parse().  But we will instead
  ** just do a search for forbidden characters.  If any of the forbidden
  ** characters appear in pCmd, we will report the string as unsafe.
  */
  const char *z;
  int n;
  z = Tcl_GetStringFromObj(pCmd, &n);
  while( n-- > 0 ){
    int c = *(z++);
    if( c=='$' || c=='[' || c==';' ) return 0;
  }
  return 1;
}

/*
** Find an SqlFunc structure with the given name.  Or create a new
** one if an existing one cannot be found.  Return a pointer to the
** structure.
*/
static SqlFunc *findSqlFunc(SqliteDb *pDb, const char *zName){
  SqlFunc *p, *pNew;
  int i;
  pNew = (SqlFunc*)Tcl_Alloc( sizeof(*pNew) + strlen30(zName) + 1 );
  pNew->zName = (char*)&pNew[1];
  for(i=0; zName[i]; i++){ pNew->zName[i] = tolower(zName[i]); }
  pNew->zName[i] = 0;
  for(p=pDb->pFunc; p; p=p->pNext){ 
    if( strcmp(p->zName, pNew->zName)==0 ){
      Tcl_Free((char*)pNew);
      return p;
    }
  }
  pNew->interp = pDb->interp;
  pNew->pScript = 0;
  pNew->pNext = pDb->pFunc;
  pDb->pFunc = pNew;
  return pNew;
}

/*
** Finalize and free a list of prepared statements
*/
static void flushStmtCache( SqliteDb *pDb ){
  SqlPreparedStmt *pPreStmt;

  while(  pDb->stmtList ){
    sqlite3_finalize( pDb->stmtList->pStmt );
    pPreStmt = pDb->stmtList;
    pDb->stmtList = pDb->stmtList->pNext;
    Tcl_Free( (char*)pPreStmt );
  }
  pDb->nStmt = 0;
  pDb->stmtLast = 0;
}

/*
** TCL calls this procedure when an sqlite3 database command is
** deleted.
*/
static void DbDeleteCmd(void *db){
  SqliteDb *pDb = (SqliteDb*)db;
  flushStmtCache(pDb);
  closeIncrblobChannels(pDb);
  sqlite3_close(pDb->db);
  while( pDb->pFunc ){
    SqlFunc *pFunc = pDb->pFunc;
    pDb->pFunc = pFunc->pNext;
    Tcl_DecrRefCount(pFunc->pScript);
    Tcl_Free((char*)pFunc);
  }
  while( pDb->pCollate ){
    SqlCollate *pCollate = pDb->pCollate;
    pDb->pCollate = pCollate->pNext;
    Tcl_Free((char*)pCollate);
  }
  if( pDb->zBusy ){
    Tcl_Free(pDb->zBusy);
  }
  if( pDb->zTrace ){
    Tcl_Free(pDb->zTrace);
  }
  if( pDb->zProfile ){
    Tcl_Free(pDb->zProfile);
  }
  if( pDb->zAuth ){
    Tcl_Free(pDb->zAuth);
  }
  if( pDb->zNull ){
    Tcl_Free(pDb->zNull);
  }
  if( pDb->pUpdateHook ){
    Tcl_DecrRefCount(pDb->pUpdateHook);
  }
  if( pDb->pRollbackHook ){
    Tcl_DecrRefCount(pDb->pRollbackHook);
  }
  if( pDb->pWalHook ){
    Tcl_DecrRefCount(pDb->pWalHook);
  }
  if( pDb->pCollateNeeded ){
    Tcl_DecrRefCount(pDb->pCollateNeeded);
  }
  Tcl_Free((char*)pDb);
}

/*
** This routine is called when a database file is locked while trying
** to execute SQL.
*/
static int DbBusyHandler(void *cd, int nTries){
  SqliteDb *pDb = (SqliteDb*)cd;
  int rc;
  char zVal[30];

  sqlite3_snprintf(sizeof(zVal), zVal, "%d", nTries);
  rc = Tcl_VarEval(pDb->interp, pDb->zBusy, " ", zVal, (char*)0);
  if( rc!=TCL_OK || atoi(Tcl_GetStringResult(pDb->interp)) ){
    return 0;
  }
  return 1;
}

#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/*
** This routine is invoked as the 'progress callback' for the database.
*/
static int DbProgressHandler(void *cd){
  SqliteDb *pDb = (SqliteDb*)cd;
  int rc;

  assert( pDb->zProgress );
  rc = Tcl_Eval(pDb->interp, pDb->zProgress);
  if( rc!=TCL_OK || atoi(Tcl_GetStringResult(pDb->interp)) ){
    return 1;
  }
  return 0;
}
#endif

#ifndef SQLITE_OMIT_TRACE
/*
** This routine is called by the SQLite trace handler whenever a new
** block of SQL is executed.  The TCL script in pDb->zTrace is executed.
*/
static void DbTraceHandler(void *cd, const char *zSql){
  SqliteDb *pDb = (SqliteDb*)cd;
  Tcl_DString str;

  Tcl_DStringInit(&str);
  Tcl_DStringAppend(&str, pDb->zTrace, -1);
  Tcl_DStringAppendElement(&str, zSql);
  Tcl_Eval(pDb->interp, Tcl_DStringValue(&str));
  Tcl_DStringFree(&str);
  Tcl_ResetResult(pDb->interp);
}
#endif

#ifndef SQLITE_OMIT_TRACE
/*
** This routine is called by the SQLite profile handler after a statement
** SQL has executed.  The TCL script in pDb->zProfile is evaluated.
*/
static void DbProfileHandler(void *cd, const char *zSql, sqlite_uint64 tm){
  SqliteDb *pDb = (SqliteDb*)cd;
  Tcl_DString str;
  char zTm[100];

  sqlite3_snprintf(sizeof(zTm)-1, zTm, "%lld", tm);
  Tcl_DStringInit(&str);
  Tcl_DStringAppend(&str, pDb->zProfile, -1);
  Tcl_DStringAppendElement(&str, zSql);
  Tcl_DStringAppendElement(&str, zTm);
  Tcl_Eval(pDb->interp, Tcl_DStringValue(&str));
  Tcl_DStringFree(&str);
  Tcl_ResetResult(pDb->interp);
}
#endif

/*
** This routine is called when a transaction is committed.  The
** TCL script in pDb->zCommit is executed.  If it returns non-zero or
** if it throws an exception, the transaction is rolled back instead
** of being committed.
*/
static int DbCommitHandler(void *cd){
  SqliteDb *pDb = (SqliteDb*)cd;
  int rc;

  rc = Tcl_Eval(pDb->interp, pDb->zCommit);
  if( rc!=TCL_OK || atoi(Tcl_GetStringResult(pDb->interp)) ){
    return 1;
  }
  return 0;
}

static void DbRollbackHandler(void *clientData){
  SqliteDb *pDb = (SqliteDb*)clientData;
  assert(pDb->pRollbackHook);
  if( TCL_OK!=Tcl_EvalObjEx(pDb->interp, pDb->pRollbackHook, 0) ){
    Tcl_BackgroundError(pDb->interp);
  }
}

/*
** This procedure handles wal_hook callbacks.
*/
static int DbWalHandler(
  void *clientData, 
  sqlite3 *db, 
  const char *zDb, 
  int nEntry
){
  int ret = SQLITE_OK;
  Tcl_Obj *p;
  SqliteDb *pDb = (SqliteDb*)clientData;
  Tcl_Interp *interp = pDb->interp;
  assert(pDb->pWalHook);

  p = Tcl_DuplicateObj(pDb->pWalHook);
  Tcl_IncrRefCount(p);
  Tcl_ListObjAppendElement(interp, p, Tcl_NewStringObj(zDb, -1));
  Tcl_ListObjAppendElement(interp, p, Tcl_NewIntObj(nEntry));
  if( TCL_OK!=Tcl_EvalObjEx(interp, p, 0) 
   || TCL_OK!=Tcl_GetIntFromObj(interp, Tcl_GetObjResult(interp), &ret)
  ){
    Tcl_BackgroundError(interp);
  }
  Tcl_DecrRefCount(p);

  return ret;
}

#if defined(SQLITE_TEST) && defined(SQLITE_ENABLE_UNLOCK_NOTIFY)
static void setTestUnlockNotifyVars(Tcl_Interp *interp, int iArg, int nArg){
  char zBuf[64];
  sprintf(zBuf, "%d", iArg);
  Tcl_SetVar(interp, "sqlite_unlock_notify_arg", zBuf, TCL_GLOBAL_ONLY);
  sprintf(zBuf, "%d", nArg);
  Tcl_SetVar(interp, "sqlite_unlock_notify_argcount", zBuf, TCL_GLOBAL_ONLY);
}
#else
# define setTestUnlockNotifyVars(x,y,z)
#endif

#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
static void DbUnlockNotify(void **apArg, int nArg){
  int i;
  for(i=0; i<nArg; i++){
    const int flags = (TCL_EVAL_GLOBAL|TCL_EVAL_DIRECT);
    SqliteDb *pDb = (SqliteDb *)apArg[i];
    setTestUnlockNotifyVars(pDb->interp, i, nArg);
    assert( pDb->pUnlockNotify);
    Tcl_EvalObjEx(pDb->interp, pDb->pUnlockNotify, flags);
    Tcl_DecrRefCount(pDb->pUnlockNotify);
    pDb->pUnlockNotify = 0;
  }
}
#endif

static void DbUpdateHandler(
  void *p, 
  int op,
  const char *zDb, 
  const char *zTbl, 
  sqlite_int64 rowid
){
  SqliteDb *pDb = (SqliteDb *)p;
  Tcl_Obj *pCmd;

  assert( pDb->pUpdateHook );
  assert( op==SQLITE_INSERT || op==SQLITE_UPDATE || op==SQLITE_DELETE );

  pCmd = Tcl_DuplicateObj(pDb->pUpdateHook);
  Tcl_IncrRefCount(pCmd);
  Tcl_ListObjAppendElement(0, pCmd, Tcl_NewStringObj(
    ( (op==SQLITE_INSERT)?"INSERT":(op==SQLITE_UPDATE)?"UPDATE":"DELETE"), -1));
  Tcl_ListObjAppendElement(0, pCmd, Tcl_NewStringObj(zDb, -1));
  Tcl_ListObjAppendElement(0, pCmd, Tcl_NewStringObj(zTbl, -1));
  Tcl_ListObjAppendElement(0, pCmd, Tcl_NewWideIntObj(rowid));
  Tcl_EvalObjEx(pDb->interp, pCmd, TCL_EVAL_DIRECT);
  Tcl_DecrRefCount(pCmd);
}

static void tclCollateNeeded(
  void *pCtx,
  sqlite3 *db,
  int enc,
  const char *zName
){
  SqliteDb *pDb = (SqliteDb *)pCtx;
  Tcl_Obj *pScript = Tcl_DuplicateObj(pDb->pCollateNeeded);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(0, pScript, Tcl_NewStringObj(zName, -1));
  Tcl_EvalObjEx(pDb->interp, pScript, 0);
  Tcl_DecrRefCount(pScript);
}

/*
** This routine is called to evaluate an SQL collation function implemented
** using TCL script.
*/
static int tclSqlCollate(
  void *pCtx,
  int nA,
  const void *zA,
  int nB,
  const void *zB
){
  SqlCollate *p = (SqlCollate *)pCtx;
  Tcl_Obj *pCmd;

  pCmd = Tcl_NewStringObj(p->zScript, -1);
  Tcl_IncrRefCount(pCmd);
  Tcl_ListObjAppendElement(p->interp, pCmd, Tcl_NewStringObj(zA, nA));
  Tcl_ListObjAppendElement(p->interp, pCmd, Tcl_NewStringObj(zB, nB));
  Tcl_EvalObjEx(p->interp, pCmd, TCL_EVAL_DIRECT);
  Tcl_DecrRefCount(pCmd);
  return (atoi(Tcl_GetStringResult(p->interp)));
}

/*
** This routine is called to evaluate an SQL function implemented
** using TCL script.
*/
static void tclSqlFunc(sqlite3_context *context, int argc, sqlite3_value**argv){
  SqlFunc *p = sqlite3_user_data(context);
  Tcl_Obj *pCmd;
  int i;
  int rc;

  if( argc==0 ){
    /* If there are no arguments to the function, call Tcl_EvalObjEx on the
    ** script object directly.  This allows the TCL compiler to generate
    ** bytecode for the command on the first invocation and thus make
    ** subsequent invocations much faster. */
    pCmd = p->pScript;
    Tcl_IncrRefCount(pCmd);
    rc = Tcl_EvalObjEx(p->interp, pCmd, 0);
    Tcl_DecrRefCount(pCmd);
  }else{
    /* If there are arguments to the function, make a shallow copy of the
    ** script object, lappend the arguments, then evaluate the copy.
    **
    ** By "shallow" copy, we mean a only the outer list Tcl_Obj is duplicated.
    ** The new Tcl_Obj contains pointers to the original list elements. 
    ** That way, when Tcl_EvalObjv() is run and shimmers the first element
    ** of the list to tclCmdNameType, that alternate representation will
    ** be preserved and reused on the next invocation.
    */
    Tcl_Obj **aArg;
    int nArg;
    if( Tcl_ListObjGetElements(p->interp, p->pScript, &nArg, &aArg) ){
      sqlite3_result_error(context, Tcl_GetStringResult(p->interp), -1); 
      return;
    }     
    pCmd = Tcl_NewListObj(nArg, aArg);
    Tcl_IncrRefCount(pCmd);
    for(i=0; i<argc; i++){
      sqlite3_value *pIn = argv[i];
      Tcl_Obj *pVal;
            
      /* Set pVal to contain the i'th column of this row. */
      switch( sqlite3_value_type(pIn) ){
        case SQLITE_BLOB: {
          int bytes = sqlite3_value_bytes(pIn);
          pVal = Tcl_NewByteArrayObj(sqlite3_value_blob(pIn), bytes);
          break;
        }
        case SQLITE_INTEGER: {
          sqlite_int64 v = sqlite3_value_int64(pIn);
          if( v>=-2147483647 && v<=2147483647 ){
            pVal = Tcl_NewIntObj(v);
          }else{
            pVal = Tcl_NewWideIntObj(v);
          }
          break;
        }
        case SQLITE_FLOAT: {
          double r = sqlite3_value_double(pIn);
          pVal = Tcl_NewDoubleObj(r);
          break;
        }
        case SQLITE_NULL: {
          pVal = Tcl_NewStringObj("", 0);
          break;
        }
        default: {
          int bytes = sqlite3_value_bytes(pIn);
          pVal = Tcl_NewStringObj((char *)sqlite3_value_text(pIn), bytes);
          break;
        }
      }
      rc = Tcl_ListObjAppendElement(p->interp, pCmd, pVal);
      if( rc ){
        Tcl_DecrRefCount(pCmd);
        sqlite3_result_error(context, Tcl_GetStringResult(p->interp), -1); 
        return;
      }
    }
    if( !p->useEvalObjv ){
      /* Tcl_EvalObjEx() will automatically call Tcl_EvalObjv() if pCmd
      ** is a list without a string representation.  To prevent this from
      ** happening, make sure pCmd has a valid string representation */
      Tcl_GetString(pCmd);
    }
    rc = Tcl_EvalObjEx(p->interp, pCmd, TCL_EVAL_DIRECT);
    Tcl_DecrRefCount(pCmd);
  }

  if( rc && rc!=TCL_RETURN ){
    sqlite3_result_error(context, Tcl_GetStringResult(p->interp), -1); 
  }else{
    Tcl_Obj *pVar = Tcl_GetObjResult(p->interp);
    int n;
    u8 *data;
    const char *zType = (pVar->typePtr ? pVar->typePtr->name : "");
    char c = zType[0];
    if( c=='b' && strcmp(zType,"bytearray")==0 && pVar->bytes==0 ){
      /* Only return a BLOB type if the Tcl variable is a bytearray and
      ** has no string representation. */
      data = Tcl_GetByteArrayFromObj(pVar, &n);
      sqlite3_result_blob(context, data, n, SQLITE_TRANSIENT);
    }else if( c=='b' && strcmp(zType,"boolean")==0 ){
      Tcl_GetIntFromObj(0, pVar, &n);
      sqlite3_result_int(context, n);
    }else if( c=='d' && strcmp(zType,"double")==0 ){
      double r;
      Tcl_GetDoubleFromObj(0, pVar, &r);
      sqlite3_result_double(context, r);
    }else if( (c=='w' && strcmp(zType,"wideInt")==0) ||
          (c=='i' && strcmp(zType,"int")==0) ){
      Tcl_WideInt v;
      Tcl_GetWideIntFromObj(0, pVar, &v);
      sqlite3_result_int64(context, v);
    }else{
      data = (unsigned char *)Tcl_GetStringFromObj(pVar, &n);
      sqlite3_result_text(context, (char *)data, n, SQLITE_TRANSIENT);
    }
  }
}

#ifndef SQLITE_OMIT_AUTHORIZATION
/*
** This is the authentication function.  It appends the authentication
** type code and the two arguments to zCmd[] then invokes the result
** on the interpreter.  The reply is examined to determine if the
** authentication fails or succeeds.
*/
static int auth_callback(
  void *pArg,
  int code,
  const char *zArg1,
  const char *zArg2,
  const char *zArg3,
  const char *zArg4
){
  char *zCode;
  Tcl_DString str;
  int rc;
  const char *zReply;
  SqliteDb *pDb = (SqliteDb*)pArg;
  if( pDb->disableAuth ) return SQLITE_OK;

  switch( code ){
    case SQLITE_COPY              : zCode="SQLITE_COPY"; break;
    case SQLITE_CREATE_INDEX      : zCode="SQLITE_CREATE_INDEX"; break;
    case SQLITE_CREATE_TABLE      : zCode="SQLITE_CREATE_TABLE"; break;
    case SQLITE_CREATE_TEMP_INDEX : zCode="SQLITE_CREATE_TEMP_INDEX"; break;
    case SQLITE_CREATE_TEMP_TABLE : zCode="SQLITE_CREATE_TEMP_TABLE"; break;
    case SQLITE_CREATE_TEMP_TRIGGER: zCode="SQLITE_CREATE_TEMP_TRIGGER"; break;
    case SQLITE_CREATE_TEMP_VIEW  : zCode="SQLITE_CREATE_TEMP_VIEW"; break;
    case SQLITE_CREATE_TRIGGER    : zCode="SQLITE_CREATE_TRIGGER"; break;
    case SQLITE_CREATE_VIEW       : zCode="SQLITE_CREATE_VIEW"; break;
    case SQLITE_DELETE            : zCode="SQLITE_DELETE"; break;
    case SQLITE_DROP_INDEX        : zCode="SQLITE_DROP_INDEX"; break;
    case SQLITE_DROP_TABLE        : zCode="SQLITE_DROP_TABLE"; break;
    case SQLITE_DROP_TEMP_INDEX   : zCode="SQLITE_DROP_TEMP_INDEX"; break;
    case SQLITE_DROP_TEMP_TABLE   : zCode="SQLITE_DROP_TEMP_TABLE"; break;
    case SQLITE_DROP_TEMP_TRIGGER : zCode="SQLITE_DROP_TEMP_TRIGGER"; break;
    case SQLITE_DROP_TEMP_VIEW    : zCode="SQLITE_DROP_TEMP_VIEW"; break;
    case SQLITE_DROP_TRIGGER      : zCode="SQLITE_DROP_TRIGGER"; break;
    case SQLITE_DROP_VIEW         : zCode="SQLITE_DROP_VIEW"; break;
    case SQLITE_INSERT            : zCode="SQLITE_INSERT"; break;
    case SQLITE_PRAGMA            : zCode="SQLITE_PRAGMA"; break;
    case SQLITE_READ              : zCode="SQLITE_READ"; break;
    case SQLITE_SELECT            : zCode="SQLITE_SELECT"; break;
    case SQLITE_TRANSACTION       : zCode="SQLITE_TRANSACTION"; break;
    case SQLITE_UPDATE            : zCode="SQLITE_UPDATE"; break;
    case SQLITE_ATTACH            : zCode="SQLITE_ATTACH"; break;
    case SQLITE_DETACH            : zCode="SQLITE_DETACH"; break;
    case SQLITE_ALTER_TABLE       : zCode="SQLITE_ALTER_TABLE"; break;
    case SQLITE_REINDEX           : zCode="SQLITE_REINDEX"; break;
    case SQLITE_ANALYZE           : zCode="SQLITE_ANALYZE"; break;
    case SQLITE_CREATE_VTABLE     : zCode="SQLITE_CREATE_VTABLE"; break;
    case SQLITE_DROP_VTABLE       : zCode="SQLITE_DROP_VTABLE"; break;
    case SQLITE_FUNCTION          : zCode="SQLITE_FUNCTION"; break;
    case SQLITE_SAVEPOINT         : zCode="SQLITE_SAVEPOINT"; break;
    default                       : zCode="????"; break;
  }
  Tcl_DStringInit(&str);
  Tcl_DStringAppend(&str, pDb->zAuth, -1);
  Tcl_DStringAppendElement(&str, zCode);
  Tcl_DStringAppendElement(&str, zArg1 ? zArg1 : "");
  Tcl_DStringAppendElement(&str, zArg2 ? zArg2 : "");
  Tcl_DStringAppendElement(&str, zArg3 ? zArg3 : "");
  Tcl_DStringAppendElement(&str, zArg4 ? zArg4 : "");
  rc = Tcl_GlobalEval(pDb->interp, Tcl_DStringValue(&str));
  Tcl_DStringFree(&str);
  zReply = Tcl_GetStringResult(pDb->interp);
  if( strcmp(zReply,"SQLITE_OK")==0 ){
    rc = SQLITE_OK;
  }else if( strcmp(zReply,"SQLITE_DENY")==0 ){
    rc = SQLITE_DENY;
  }else if( strcmp(zReply,"SQLITE_IGNORE")==0 ){
    rc = SQLITE_IGNORE;
  }else{
    rc = 999;
  }
  return rc;
}
#endif /* SQLITE_OMIT_AUTHORIZATION */

/*
** zText is a pointer to text obtained via an sqlite3_result_text()
** or similar interface. This routine returns a Tcl string object, 
** reference count set to 0, containing the text. If a translation
** between iso8859 and UTF-8 is required, it is preformed.
*/
static Tcl_Obj *dbTextToObj(char const *zText){
  Tcl_Obj *pVal;
#ifdef UTF_TRANSLATION_NEEDED
  Tcl_DString dCol;
  Tcl_DStringInit(&dCol);
  Tcl_ExternalToUtfDString(NULL, zText, -1, &dCol);
  pVal = Tcl_NewStringObj(Tcl_DStringValue(&dCol), -1);
  Tcl_DStringFree(&dCol);
#else
  pVal = Tcl_NewStringObj(zText, -1);
#endif
  return pVal;
}

/*
** This routine reads a line of text from FILE in, stores
** the text in memory obtained from malloc() and returns a pointer
** to the text.  NULL is returned at end of file, or if malloc()
** fails.
**
** The interface is like "readline" but no command-line editing
** is done.
**
** copied from shell.c from '.import' command
*/
static char *local_getline(char *zPrompt, FILE *in){
  char *zLine;
  int nLine;
  int n;
  int eol;

  nLine = 100;
  zLine = malloc( nLine );
  if( zLine==0 ) return 0;
  n = 0;
  eol = 0;
  while( !eol ){
    if( n+100>nLine ){
      nLine = nLine*2 + 100;
      zLine = realloc(zLine, nLine);
      if( zLine==0 ) return 0;
    }
    if( fgets(&zLine[n], nLine - n, in)==0 ){
      if( n==0 ){
        free(zLine);
        return 0;
      }
      zLine[n] = 0;
      eol = 1;
      break;
    }
    while( zLine[n] ){ n++; }
    if( n>0 && zLine[n-1]=='\n' ){
      n--;
      zLine[n] = 0;
      eol = 1;
    }
  }
  zLine = realloc( zLine, n+1 );
  return zLine;
}


/*
** This function is part of the implementation of the command:
**
**   $db transaction [-deferred|-immediate|-exclusive] SCRIPT
**
** It is invoked after evaluating the script SCRIPT to commit or rollback
** the transaction or savepoint opened by the [transaction] command.
*/
static int DbTransPostCmd(
  ClientData data[],                   /* data[0] is the Sqlite3Db* for $db */
  Tcl_Interp *interp,                  /* Tcl interpreter */
  int result                           /* Result of evaluating SCRIPT */
){
  static const char *azEnd[] = {
    "RELEASE _tcl_transaction",        /* rc==TCL_ERROR, nTransaction!=0 */
    "COMMIT",                          /* rc!=TCL_ERROR, nTransaction==0 */
    "ROLLBACK TO _tcl_transaction ; RELEASE _tcl_transaction",
    "ROLLBACK"                         /* rc==TCL_ERROR, nTransaction==0 */
  };
  SqliteDb *pDb = (SqliteDb*)data[0];
  int rc = result;
  const char *zEnd;

  pDb->nTransaction--;
  zEnd = azEnd[(rc==TCL_ERROR)*2 + (pDb->nTransaction==0)];

  pDb->disableAuth++;
  if( sqlite3_exec(pDb->db, zEnd, 0, 0, 0) ){
      /* This is a tricky scenario to handle. The most likely cause of an
      ** error is that the exec() above was an attempt to commit the 
      ** top-level transaction that returned SQLITE_BUSY. Or, less likely,
      ** that an IO-error has occured. In either case, throw a Tcl exception
      ** and try to rollback the transaction.
      **
      ** But it could also be that the user executed one or more BEGIN, 
      ** COMMIT, SAVEPOINT, RELEASE or ROLLBACK commands that are confusing
      ** this method's logic. Not clear how this would be best handled.
      */
    if( rc!=TCL_ERROR ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
      rc = TCL_ERROR;
    }
    sqlite3_exec(pDb->db, "ROLLBACK", 0, 0, 0);
  }
  pDb->disableAuth--;

  return rc;
}

/*
** Search the cache for a prepared-statement object that implements the
** first SQL statement in the buffer pointed to by parameter zIn. If
** no such prepared-statement can be found, allocate and prepare a new
** one. In either case, bind the current values of the relevant Tcl
** variables to any $var, :var or @var variables in the statement. Before
** returning, set *ppPreStmt to point to the prepared-statement object.
**
** Output parameter *pzOut is set to point to the next SQL statement in
** buffer zIn, or to the '\0' byte at the end of zIn if there is no
** next statement.
**
** If successful, TCL_OK is returned. Otherwise, TCL_ERROR is returned
** and an error message loaded into interpreter pDb->interp.
*/
static int dbPrepareAndBind(
  SqliteDb *pDb,                  /* Database object */
  char const *zIn,                /* SQL to compile */
  char const **pzOut,             /* OUT: Pointer to next SQL statement */
  SqlPreparedStmt **ppPreStmt     /* OUT: Object used to cache statement */
){
  const char *zSql = zIn;         /* Pointer to first SQL statement in zIn */
  sqlite3_stmt *pStmt;            /* Prepared statement object */
  SqlPreparedStmt *pPreStmt;      /* Pointer to cached statement */
  int nSql;                       /* Length of zSql in bytes */
  int nVar;                       /* Number of variables in statement */
  int iParm = 0;                  /* Next free entry in apParm */
  int i;
  Tcl_Interp *interp = pDb->interp;

  *ppPreStmt = 0;

  /* Trim spaces from the start of zSql and calculate the remaining length. */
  while( isspace(zSql[0]) ){ zSql++; }
  nSql = strlen30(zSql);

  for(pPreStmt = pDb->stmtList; pPreStmt; pPreStmt=pPreStmt->pNext){
    int n = pPreStmt->nSql;
    if( nSql>=n 
        && memcmp(pPreStmt->zSql, zSql, n)==0
        && (zSql[n]==0 || zSql[n-1]==';')
    ){
      pStmt = pPreStmt->pStmt;
      *pzOut = &zSql[pPreStmt->nSql];

      /* When a prepared statement is found, unlink it from the
      ** cache list.  It will later be added back to the beginning
      ** of the cache list in order to implement LRU replacement.
      */
      if( pPreStmt->pPrev ){
        pPreStmt->pPrev->pNext = pPreStmt->pNext;
      }else{
        pDb->stmtList = pPreStmt->pNext;
      }
      if( pPreStmt->pNext ){
        pPreStmt->pNext->pPrev = pPreStmt->pPrev;
      }else{
        pDb->stmtLast = pPreStmt->pPrev;
      }
      pDb->nStmt--;
      nVar = sqlite3_bind_parameter_count(pStmt);
      break;
    }
  }
  
  /* If no prepared statement was found. Compile the SQL text. Also allocate
  ** a new SqlPreparedStmt structure.  */
  if( pPreStmt==0 ){
    int nByte;

    if( SQLITE_OK!=sqlite3_prepare_v2(pDb->db, zSql, -1, &pStmt, pzOut) ){
      Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
      return TCL_ERROR;
    }
    if( pStmt==0 ){
      if( SQLITE_OK!=sqlite3_errcode(pDb->db) ){
        /* A compile-time error in the statement. */
        Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
        return TCL_ERROR;
      }else{
        /* The statement was a no-op.  Continue to the next statement
        ** in the SQL string.
        */
        return TCL_OK;
      }
    }

    assert( pPreStmt==0 );
    nVar = sqlite3_bind_parameter_count(pStmt);
    nByte = sizeof(SqlPreparedStmt) + nVar*sizeof(Tcl_Obj *);
    pPreStmt = (SqlPreparedStmt*)Tcl_Alloc(nByte);
    memset(pPreStmt, 0, nByte);

    pPreStmt->pStmt = pStmt;
    pPreStmt->nSql = (*pzOut - zSql);
    pPreStmt->zSql = sqlite3_sql(pStmt);
    pPreStmt->apParm = (Tcl_Obj **)&pPreStmt[1];
  }
  assert( pPreStmt );
  assert( strlen30(pPreStmt->zSql)==pPreStmt->nSql );
  assert( 0==memcmp(pPreStmt->zSql, zSql, pPreStmt->nSql) );

  /* Bind values to parameters that begin with $ or : */  
  for(i=1; i<=nVar; i++){
    const char *zVar = sqlite3_bind_parameter_name(pStmt, i);
    if( zVar!=0 && (zVar[0]=='$' || zVar[0]==':' || zVar[0]=='@') ){
      Tcl_Obj *pVar = Tcl_GetVar2Ex(interp, &zVar[1], 0, 0);
      if( pVar ){
        int n;
        u8 *data;
        const char *zType = (pVar->typePtr ? pVar->typePtr->name : "");
        char c = zType[0];
        if( zVar[0]=='@' ||
           (c=='b' && strcmp(zType,"bytearray")==0 && pVar->bytes==0) ){
          /* Load a BLOB type if the Tcl variable is a bytearray and
          ** it has no string representation or the host
          ** parameter name begins with "@". */
          data = Tcl_GetByteArrayFromObj(pVar, &n);
          sqlite3_bind_blob(pStmt, i, data, n, SQLITE_STATIC);
          Tcl_IncrRefCount(pVar);
          pPreStmt->apParm[iParm++] = pVar;
        }else if( c=='b' && strcmp(zType,"boolean")==0 ){
          Tcl_GetIntFromObj(interp, pVar, &n);
          sqlite3_bind_int(pStmt, i, n);
        }else if( c=='d' && strcmp(zType,"double")==0 ){
          double r;
          Tcl_GetDoubleFromObj(interp, pVar, &r);
          sqlite3_bind_double(pStmt, i, r);
        }else if( (c=='w' && strcmp(zType,"wideInt")==0) ||
              (c=='i' && strcmp(zType,"int")==0) ){
          Tcl_WideInt v;
          Tcl_GetWideIntFromObj(interp, pVar, &v);
          sqlite3_bind_int64(pStmt, i, v);
        }else{
          data = (unsigned char *)Tcl_GetStringFromObj(pVar, &n);
          sqlite3_bind_text(pStmt, i, (char *)data, n, SQLITE_STATIC);
          Tcl_IncrRefCount(pVar);
          pPreStmt->apParm[iParm++] = pVar;
        }
      }else{
        sqlite3_bind_null(pStmt, i);
      }
    }
  }
  pPreStmt->nParm = iParm;
  *ppPreStmt = pPreStmt;

  return TCL_OK;
}


/*
** Release a statement reference obtained by calling dbPrepareAndBind().
** There should be exactly one call to this function for each call to
** dbPrepareAndBind().
**
** If the discard parameter is non-zero, then the statement is deleted
** immediately. Otherwise it is added to the LRU list and may be returned
** by a subsequent call to dbPrepareAndBind().
*/
static void dbReleaseStmt(
  SqliteDb *pDb,                  /* Database handle */
  SqlPreparedStmt *pPreStmt,      /* Prepared statement handle to release */
  int discard                     /* True to delete (not cache) the pPreStmt */
){
  int i;

  /* Free the bound string and blob parameters */
  for(i=0; i<pPreStmt->nParm; i++){
    Tcl_DecrRefCount(pPreStmt->apParm[i]);
  }
  pPreStmt->nParm = 0;

  if( pDb->maxStmt<=0 || discard ){
    /* If the cache is turned off, deallocated the statement */
    sqlite3_finalize(pPreStmt->pStmt);
    Tcl_Free((char *)pPreStmt);
  }else{
    /* Add the prepared statement to the beginning of the cache list. */
    pPreStmt->pNext = pDb->stmtList;
    pPreStmt->pPrev = 0;
    if( pDb->stmtList ){
     pDb->stmtList->pPrev = pPreStmt;
    }
    pDb->stmtList = pPreStmt;
    if( pDb->stmtLast==0 ){
      assert( pDb->nStmt==0 );
      pDb->stmtLast = pPreStmt;
    }else{
      assert( pDb->nStmt>0 );
    }
    pDb->nStmt++;
   
    /* If we have too many statement in cache, remove the surplus from 
    ** the end of the cache list.  */
    while( pDb->nStmt>pDb->maxStmt ){
      sqlite3_finalize(pDb->stmtLast->pStmt);
      pDb->stmtLast = pDb->stmtLast->pPrev;
      Tcl_Free((char*)pDb->stmtLast->pNext);
      pDb->stmtLast->pNext = 0;
      pDb->nStmt--;
    }
  }
}

/*
** Structure used with dbEvalXXX() functions:
**
**   dbEvalInit()
**   dbEvalStep()
**   dbEvalFinalize()
**   dbEvalRowInfo()
**   dbEvalColumnValue()
*/
typedef struct DbEvalContext DbEvalContext;
struct DbEvalContext {
  SqliteDb *pDb;                  /* Database handle */
  Tcl_Obj *pSql;                  /* Object holding string zSql */
  const char *zSql;               /* Remaining SQL to execute */
  SqlPreparedStmt *pPreStmt;      /* Current statement */
  int nCol;                       /* Number of columns returned by pStmt */
  Tcl_Obj *pArray;                /* Name of array variable */
  Tcl_Obj **apColName;            /* Array of column names */
};

/*
** Release any cache of column names currently held as part of
** the DbEvalContext structure passed as the first argument.
*/
static void dbReleaseColumnNames(DbEvalContext *p){
  if( p->apColName ){
    int i;
    for(i=0; i<p->nCol; i++){
      Tcl_DecrRefCount(p->apColName[i]);
    }
    Tcl_Free((char *)p->apColName);
    p->apColName = 0;
  }
  p->nCol = 0;
}

/*
** Initialize a DbEvalContext structure.
**
** If pArray is not NULL, then it contains the name of a Tcl array
** variable. The "*" member of this array is set to a list containing
** the names of the columns returned by the statement as part of each
** call to dbEvalStep(), in order from left to right. e.g. if the names 
** of the returned columns are a, b and c, it does the equivalent of the 
** tcl command:
**
**     set ${pArray}(*) {a b c}
*/
static void dbEvalInit(
  DbEvalContext *p,               /* Pointer to structure to initialize */
  SqliteDb *pDb,                  /* Database handle */
  Tcl_Obj *pSql,                  /* Object containing SQL script */
  Tcl_Obj *pArray                 /* Name of Tcl array to set (*) element of */
){
  memset(p, 0, sizeof(DbEvalContext));
  p->pDb = pDb;
  p->zSql = Tcl_GetString(pSql);
  p->pSql = pSql;
  Tcl_IncrRefCount(pSql);
  if( pArray ){
    p->pArray = pArray;
    Tcl_IncrRefCount(pArray);
  }
}

/*
** Obtain information about the row that the DbEvalContext passed as the
** first argument currently points to.
*/
static void dbEvalRowInfo(
  DbEvalContext *p,               /* Evaluation context */
  int *pnCol,                     /* OUT: Number of column names */
  Tcl_Obj ***papColName           /* OUT: Array of column names */
){
  /* Compute column names */
  if( 0==p->apColName ){
    sqlite3_stmt *pStmt = p->pPreStmt->pStmt;
    int i;                        /* Iterator variable */
    int nCol;                     /* Number of columns returned by pStmt */
    Tcl_Obj **apColName = 0;      /* Array of column names */

    p->nCol = nCol = sqlite3_column_count(pStmt);
    if( nCol>0 && (papColName || p->pArray) ){
      apColName = (Tcl_Obj**)Tcl_Alloc( sizeof(Tcl_Obj*)*nCol );
      for(i=0; i<nCol; i++){
        apColName[i] = dbTextToObj(sqlite3_column_name(pStmt,i));
        Tcl_IncrRefCount(apColName[i]);
      }
      p->apColName = apColName;
    }

    /* If results are being stored in an array variable, then create
    ** the array(*) entry for that array
    */
    if( p->pArray ){
      Tcl_Interp *interp = p->pDb->interp;
      Tcl_Obj *pColList = Tcl_NewObj();
      Tcl_Obj *pStar = Tcl_NewStringObj("*", -1);

      for(i=0; i<nCol; i++){
        Tcl_ListObjAppendElement(interp, pColList, apColName[i]);
      }
      Tcl_IncrRefCount(pStar);
      Tcl_ObjSetVar2(interp, p->pArray, pStar, pColList, 0);
      Tcl_DecrRefCount(pStar);
    }
  }

  if( papColName ){
    *papColName = p->apColName;
  }
  if( pnCol ){
    *pnCol = p->nCol;
  }
}

/*
** Return one of TCL_OK, TCL_BREAK or TCL_ERROR. If TCL_ERROR is
** returned, then an error message is stored in the interpreter before
** returning.
**
** A return value of TCL_OK means there is a row of data available. The
** data may be accessed using dbEvalRowInfo() and dbEvalColumnValue(). This
** is analogous to a return of SQLITE_ROW from sqlite3_step(). If TCL_BREAK
** is returned, then the SQL script has finished executing and there are
** no further rows available. This is similar to SQLITE_DONE.
*/
static int dbEvalStep(DbEvalContext *p){
  while( p->zSql[0] || p->pPreStmt ){
    int rc;
    if( p->pPreStmt==0 ){
      rc = dbPrepareAndBind(p->pDb, p->zSql, &p->zSql, &p->pPreStmt);
      if( rc!=TCL_OK ) return rc;
    }else{
      int rcs;
      SqliteDb *pDb = p->pDb;
      SqlPreparedStmt *pPreStmt = p->pPreStmt;
      sqlite3_stmt *pStmt = pPreStmt->pStmt;

      rcs = sqlite3_step(pStmt);
      if( rcs==SQLITE_ROW ){
        return TCL_OK;
      }
      if( p->pArray ){
        dbEvalRowInfo(p, 0, 0);
      }
      rcs = sqlite3_reset(pStmt);

      pDb->nStep = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_FULLSCAN_STEP,1);
      pDb->nSort = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_SORT,1);
      pDb->nIndex = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_AUTOINDEX,1);
      dbReleaseColumnNames(p);
      p->pPreStmt = 0;

      if( rcs!=SQLITE_OK ){
        /* If a run-time error occurs, report the error and stop reading
        ** the SQL.  */
        Tcl_SetObjResult(pDb->interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
        dbReleaseStmt(pDb, pPreStmt, 1);
        return TCL_ERROR;
      }else{
        dbReleaseStmt(pDb, pPreStmt, 0);
      }
    }
  }

  /* Finished */
  return TCL_BREAK;
}

/*
** Free all resources currently held by the DbEvalContext structure passed
** as the first argument. There should be exactly one call to this function
** for each call to dbEvalInit().
*/
static void dbEvalFinalize(DbEvalContext *p){
  if( p->pPreStmt ){
    sqlite3_reset(p->pPreStmt->pStmt);
    dbReleaseStmt(p->pDb, p->pPreStmt, 0);
    p->pPreStmt = 0;
  }
  if( p->pArray ){
    Tcl_DecrRefCount(p->pArray);
    p->pArray = 0;
  }
  Tcl_DecrRefCount(p->pSql);
  dbReleaseColumnNames(p);
}

/*
** Return a pointer to a Tcl_Obj structure with ref-count 0 that contains
** the value for the iCol'th column of the row currently pointed to by
** the DbEvalContext structure passed as the first argument.
*/
static Tcl_Obj *dbEvalColumnValue(DbEvalContext *p, int iCol){
  sqlite3_stmt *pStmt = p->pPreStmt->pStmt;
  switch( sqlite3_column_type(pStmt, iCol) ){
    case SQLITE_BLOB: {
      int bytes = sqlite3_column_bytes(pStmt, iCol);
      const char *zBlob = sqlite3_column_blob(pStmt, iCol);
      if( !zBlob ) bytes = 0;
      return Tcl_NewByteArrayObj((u8*)zBlob, bytes);
    }
    case SQLITE_INTEGER: {
      sqlite_int64 v = sqlite3_column_int64(pStmt, iCol);
      if( v>=-2147483647 && v<=2147483647 ){
        return Tcl_NewIntObj(v);
      }else{
        return Tcl_NewWideIntObj(v);
      }
    }
    case SQLITE_FLOAT: {
      return Tcl_NewDoubleObj(sqlite3_column_double(pStmt, iCol));
    }
    case SQLITE_NULL: {
      return dbTextToObj(p->pDb->zNull);
    }
  }

  return dbTextToObj((char *)sqlite3_column_text(pStmt, iCol));
}

/*
** If using Tcl version 8.6 or greater, use the NR functions to avoid
** recursive evalution of scripts by the [db eval] and [db trans]
** commands. Even if the headers used while compiling the extension
** are 8.6 or newer, the code still tests the Tcl version at runtime.
** This allows stubs-enabled builds to be used with older Tcl libraries.
*/
#if TCL_MAJOR_VERSION>8 || (TCL_MAJOR_VERSION==8 && TCL_MINOR_VERSION>=6)
# define SQLITE_TCL_NRE 1
static int DbUseNre(void){
  int major, minor;
  Tcl_GetVersion(&major, &minor, 0, 0);
  return( (major==8 && minor>=6) || major>8 );
}
#else
/* 
** Compiling using headers earlier than 8.6. In this case NR cannot be
** used, so DbUseNre() to always return zero. Add #defines for the other
** Tcl_NRxxx() functions to prevent them from causing compilation errors,
** even though the only invocations of them are within conditional blocks 
** of the form:
**
**   if( DbUseNre() ) { ... }
*/
# define SQLITE_TCL_NRE 0
# define DbUseNre() 0
# define Tcl_NRAddCallback(a,b,c,d,e,f) 0
# define Tcl_NREvalObj(a,b,c) 0
# define Tcl_NRCreateCommand(a,b,c,d,e,f) 0
#endif

/*
** This function is part of the implementation of the command:
**
**   $db eval SQL ?ARRAYNAME? SCRIPT
*/
static int DbEvalNextCmd(
  ClientData data[],                   /* data[0] is the (DbEvalContext*) */
  Tcl_Interp *interp,                  /* Tcl interpreter */
  int result                           /* Result so far */
){
  int rc = result;                     /* Return code */

  /* The first element of the data[] array is a pointer to a DbEvalContext
  ** structure allocated using Tcl_Alloc(). The second element of data[]
  ** is a pointer to a Tcl_Obj containing the script to run for each row
  ** returned by the queries encapsulated in data[0]. */
  DbEvalContext *p = (DbEvalContext *)data[0];
  Tcl_Obj *pScript = (Tcl_Obj *)data[1];
  Tcl_Obj *pArray = p->pArray;

  while( (rc==TCL_OK || rc==TCL_CONTINUE) && TCL_OK==(rc = dbEvalStep(p)) ){
    int i;
    int nCol;
    Tcl_Obj **apColName;
    dbEvalRowInfo(p, &nCol, &apColName);
    for(i=0; i<nCol; i++){
      Tcl_Obj *pVal = dbEvalColumnValue(p, i);
      if( pArray==0 ){
        Tcl_ObjSetVar2(interp, apColName[i], 0, pVal, 0);
      }else{
        Tcl_ObjSetVar2(interp, pArray, apColName[i], pVal, 0);
      }
    }

    /* The required interpreter variables are now populated with the data 
    ** from the current row. If using NRE, schedule callbacks to evaluate
    ** script pScript, then to invoke this function again to fetch the next
    ** row (or clean up if there is no next row or the script throws an
    ** exception). After scheduling the callbacks, return control to the 
    ** caller.
    **
    ** If not using NRE, evaluate pScript directly and continue with the
    ** next iteration of this while(...) loop.  */
    if( DbUseNre() ){
      Tcl_NRAddCallback(interp, DbEvalNextCmd, (void*)p, (void*)pScript, 0, 0);
      return Tcl_NREvalObj(interp, pScript, 0);
    }else{
      rc = Tcl_EvalObjEx(interp, pScript, 0);
    }
  }

  Tcl_DecrRefCount(pScript);
  dbEvalFinalize(p);
  Tcl_Free((char *)p);

  if( rc==TCL_OK || rc==TCL_BREAK ){
    Tcl_ResetResult(interp);
    rc = TCL_OK;
  }
  return rc;
}

/*
** The "sqlite" command below creates a new Tcl command for each
** connection it opens to an SQLite database.  This routine is invoked
** whenever one of those connection-specific commands is executed
** in Tcl.  For example, if you run Tcl code like this:
**
**       sqlite3 db1  "my_database"
**       db1 close
**
** The first command opens a connection to the "my_database" database
** and calls that connection "db1".  The second command causes this
** subroutine to be invoked.
*/
static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
  SqliteDb *pDb = (SqliteDb*)cd;
  int choice;
  int rc = TCL_OK;
  static const char *DB_strs[] = {
    "authorizer",         "backup",            "busy",
    "cache",              "changes",           "close",
    "collate",            "collation_needed",  "commit_hook",
    "complete",           "copy",              "enable_load_extension",
    "errorcode",          "eval",              "exists",
    "function",           "incrblob",          "interrupt",
    "last_insert_rowid",  "nullvalue",         "onecolumn",
    "profile",            "progress",          "rekey",
    "restore",            "rollback_hook",     "status",
    "timeout",            "total_changes",     "trace",
    "transaction",        "unlock_notify",     "update_hook",
    "version",            "wal_hook",          0
  };
  enum DB_enum {
    DB_AUTHORIZER,        DB_BACKUP,           DB_BUSY,
    DB_CACHE,             DB_CHANGES,          DB_CLOSE,
    DB_COLLATE,           DB_COLLATION_NEEDED, DB_COMMIT_HOOK,
    DB_COMPLETE,          DB_COPY,             DB_ENABLE_LOAD_EXTENSION,
    DB_ERRORCODE,         DB_EVAL,             DB_EXISTS,
    DB_FUNCTION,          DB_INCRBLOB,         DB_INTERRUPT,
    DB_LAST_INSERT_ROWID, DB_NULLVALUE,        DB_ONECOLUMN,
    DB_PROFILE,           DB_PROGRESS,         DB_REKEY,
    DB_RESTORE,           DB_ROLLBACK_HOOK,    DB_STATUS,
    DB_TIMEOUT,           DB_TOTAL_CHANGES,    DB_TRACE,
    DB_TRANSACTION,       DB_UNLOCK_NOTIFY,    DB_UPDATE_HOOK,
    DB_VERSION,           DB_WAL_HOOK
  };
  /* don't leave trailing commas on DB_enum, it confuses the AIX xlc compiler */

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;
  }
  if( Tcl_GetIndexFromObj(interp, objv[1], DB_strs, "option", 0, &choice) ){
    return TCL_ERROR;
  }

  switch( (enum DB_enum)choice ){

  /*    $db authorizer ?CALLBACK?
  **
  ** Invoke the given callback to authorize each SQL operation as it is
  ** compiled.  5 arguments are appended to the callback before it is
  ** invoked:
  **
  **   (1) The authorization type (ex: SQLITE_CREATE_TABLE, SQLITE_INSERT, ...)
  **   (2) First descriptive name (depends on authorization type)
  **   (3) Second descriptive name
  **   (4) Name of the database (ex: "main", "temp")
  **   (5) Name of trigger that is doing the access
  **
  ** The callback should return on of the following strings: SQLITE_OK,
  ** SQLITE_IGNORE, or SQLITE_DENY.  Any other return value is an error.
  **
  ** If this method is invoked with no arguments, the current authorization
  ** callback string is returned.
  */
  case DB_AUTHORIZER: {
#ifdef SQLITE_OMIT_AUTHORIZATION
    Tcl_AppendResult(interp, "authorization not available in this build", 0);
    return TCL_ERROR;
#else
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zAuth ){
        Tcl_AppendResult(interp, pDb->zAuth, 0);
      }
    }else{
      char *zAuth;
      int len;
      if( pDb->zAuth ){
        Tcl_Free(pDb->zAuth);
      }
      zAuth = Tcl_GetStringFromObj(objv[2], &len);
      if( zAuth && len>0 ){
        pDb->zAuth = Tcl_Alloc( len + 1 );
        memcpy(pDb->zAuth, zAuth, len+1);
      }else{
        pDb->zAuth = 0;
      }
      if( pDb->zAuth ){
        pDb->interp = interp;
        sqlite3_set_authorizer(pDb->db, auth_callback, pDb);
      }else{
        sqlite3_set_authorizer(pDb->db, 0, 0);
      }
    }
#endif
    break;
  }

  /*    $db backup ?DATABASE? FILENAME
  **
  ** Open or create a database file named FILENAME.  Transfer the
  ** content of local database DATABASE (default: "main") into the
  ** FILENAME database.
  */
  case DB_BACKUP: {
    const char *zDestFile;
    const char *zSrcDb;
    sqlite3 *pDest;
    sqlite3_backup *pBackup;

    if( objc==3 ){
      zSrcDb = "main";
      zDestFile = Tcl_GetString(objv[2]);
    }else if( objc==4 ){
      zSrcDb = Tcl_GetString(objv[2]);
      zDestFile = Tcl_GetString(objv[3]);
    }else{
      Tcl_WrongNumArgs(interp, 2, objv, "?DATABASE? FILENAME");
      return TCL_ERROR;
    }
    rc = sqlite3_open(zDestFile, &pDest);
    if( rc!=SQLITE_OK ){
      Tcl_AppendResult(interp, "cannot open target database: ",
           sqlite3_errmsg(pDest), (char*)0);
      sqlite3_close(pDest);
      return TCL_ERROR;
    }
    pBackup = sqlite3_backup_init(pDest, "main", pDb->db, zSrcDb);
    if( pBackup==0 ){
      Tcl_AppendResult(interp, "backup failed: ",
           sqlite3_errmsg(pDest), (char*)0);
      sqlite3_close(pDest);
      return TCL_ERROR;
    }
    while(  (rc = sqlite3_backup_step(pBackup,100))==SQLITE_OK ){}
    sqlite3_backup_finish(pBackup);
    if( rc==SQLITE_DONE ){
      rc = TCL_OK;
    }else{
      Tcl_AppendResult(interp, "backup failed: ",
           sqlite3_errmsg(pDest), (char*)0);
      rc = TCL_ERROR;
    }
    sqlite3_close(pDest);
    break;
  }

  /*    $db busy ?CALLBACK?
  **
  ** Invoke the given callback if an SQL statement attempts to open
  ** a locked database file.
  */
  case DB_BUSY: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "CALLBACK");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zBusy ){
        Tcl_AppendResult(interp, pDb->zBusy, 0);
      }
    }else{
      char *zBusy;
      int len;
      if( pDb->zBusy ){
        Tcl_Free(pDb->zBusy);
      }
      zBusy = Tcl_GetStringFromObj(objv[2], &len);
      if( zBusy && len>0 ){
        pDb->zBusy = Tcl_Alloc( len + 1 );
        memcpy(pDb->zBusy, zBusy, len+1);
      }else{
        pDb->zBusy = 0;
      }
      if( pDb->zBusy ){
        pDb->interp = interp;
        sqlite3_busy_handler(pDb->db, DbBusyHandler, pDb);
      }else{
        sqlite3_busy_handler(pDb->db, 0, 0);
      }
    }
    break;
  }

  /*     $db cache flush
  **     $db cache size n
  **
  ** Flush the prepared statement cache, or set the maximum number of
  ** cached statements.
  */
  case DB_CACHE: {
    char *subCmd;
    int n;

    if( objc<=2 ){
      Tcl_WrongNumArgs(interp, 1, objv, "cache option ?arg?");
      return TCL_ERROR;
    }
    subCmd = Tcl_GetStringFromObj( objv[2], 0 );
    if( *subCmd=='f' && strcmp(subCmd,"flush")==0 ){
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "flush");
        return TCL_ERROR;
      }else{
        flushStmtCache( pDb );
      }
    }else if( *subCmd=='s' && strcmp(subCmd,"size")==0 ){
      if( objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "size n");
        return TCL_ERROR;
      }else{
        if( TCL_ERROR==Tcl_GetIntFromObj(interp, objv[3], &n) ){
          Tcl_AppendResult( interp, "cannot convert \"", 
               Tcl_GetStringFromObj(objv[3],0), "\" to integer", 0);
          return TCL_ERROR;
        }else{
          if( n<0 ){
            flushStmtCache( pDb );
            n = 0;
          }else if( n>MAX_PREPARED_STMTS ){
            n = MAX_PREPARED_STMTS;
          }
          pDb->maxStmt = n;
        }
      }
    }else{
      Tcl_AppendResult( interp, "bad option \"", 
          Tcl_GetStringFromObj(objv[2],0), "\": must be flush or size", 0);
      return TCL_ERROR;
    }
    break;
  }

  /*     $db changes
  **
  ** Return the number of rows that were modified, inserted, or deleted by
  ** the most recent INSERT, UPDATE or DELETE statement, not including 
  ** any changes made by trigger programs.
  */
  case DB_CHANGES: {
    Tcl_Obj *pResult;
    if( objc!=2 ){
      Tcl_WrongNumArgs(interp, 2, objv, "");
      return TCL_ERROR;
    }
    pResult = Tcl_GetObjResult(interp);
    Tcl_SetIntObj(pResult, sqlite3_changes(pDb->db));
    break;
  }

  /*    $db close
  **
  ** Shutdown the database
  */
  case DB_CLOSE: {
    Tcl_DeleteCommand(interp, Tcl_GetStringFromObj(objv[0], 0));
    break;
  }

  /*
  **     $db collate NAME SCRIPT
  **
  ** Create a new SQL collation function called NAME.  Whenever
  ** that function is called, invoke SCRIPT to evaluate the function.
  */
  case DB_COLLATE: {
    SqlCollate *pCollate;
    char *zName;
    char *zScript;
    int nScript;
    if( objc!=4 ){
      Tcl_WrongNumArgs(interp, 2, objv, "NAME SCRIPT");
      return TCL_ERROR;
    }
    zName = Tcl_GetStringFromObj(objv[2], 0);
    zScript = Tcl_GetStringFromObj(objv[3], &nScript);
    pCollate = (SqlCollate*)Tcl_Alloc( sizeof(*pCollate) + nScript + 1 );
    if( pCollate==0 ) return TCL_ERROR;
    pCollate->interp = interp;
    pCollate->pNext = pDb->pCollate;
    pCollate->zScript = (char*)&pCollate[1];
    pDb->pCollate = pCollate;
    memcpy(pCollate->zScript, zScript, nScript+1);
    if( sqlite3_create_collation(pDb->db, zName, SQLITE_UTF8, 
        pCollate, tclSqlCollate) ){
      Tcl_SetResult(interp, (char *)sqlite3_errmsg(pDb->db), TCL_VOLATILE);
      return TCL_ERROR;
    }
    break;
  }

  /*
  **     $db collation_needed SCRIPT
  **
  ** Create a new SQL collation function called NAME.  Whenever
  ** that function is called, invoke SCRIPT to evaluate the function.
  */
  case DB_COLLATION_NEEDED: {
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "SCRIPT");
      return TCL_ERROR;
    }
    if( pDb->pCollateNeeded ){
      Tcl_DecrRefCount(pDb->pCollateNeeded);
    }
    pDb->pCollateNeeded = Tcl_DuplicateObj(objv[2]);
    Tcl_IncrRefCount(pDb->pCollateNeeded);
    sqlite3_collation_needed(pDb->db, pDb, tclCollateNeeded);
    break;
  }

  /*    $db commit_hook ?CALLBACK?
  **
  ** Invoke the given callback just before committing every SQL transaction.
  ** If the callback throws an exception or returns non-zero, then the
  ** transaction is aborted.  If CALLBACK is an empty string, the callback
  ** is disabled.
  */
  case DB_COMMIT_HOOK: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zCommit ){
        Tcl_AppendResult(interp, pDb->zCommit, 0);
      }
    }else{
      char *zCommit;
      int len;
      if( pDb->zCommit ){
        Tcl_Free(pDb->zCommit);
      }
      zCommit = Tcl_GetStringFromObj(objv[2], &len);
      if( zCommit && len>0 ){
        pDb->zCommit = Tcl_Alloc( len + 1 );
        memcpy(pDb->zCommit, zCommit, len+1);
      }else{
        pDb->zCommit = 0;
      }
      if( pDb->zCommit ){
        pDb->interp = interp;
        sqlite3_commit_hook(pDb->db, DbCommitHandler, pDb);
      }else{
        sqlite3_commit_hook(pDb->db, 0, 0);
      }
    }
    break;
  }

  /*    $db complete SQL
  **
  ** Return TRUE if SQL is a complete SQL statement.  Return FALSE if
  ** additional lines of input are needed.  This is similar to the
  ** built-in "info complete" command of Tcl.
  */
  case DB_COMPLETE: {
#ifndef SQLITE_OMIT_COMPLETE
    Tcl_Obj *pResult;
    int isComplete;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "SQL");
      return TCL_ERROR;
    }
    isComplete = sqlite3_complete( Tcl_GetStringFromObj(objv[2], 0) );
    pResult = Tcl_GetObjResult(interp);
    Tcl_SetBooleanObj(pResult, isComplete);
#endif
    break;
  }

  /*    $db copy conflict-algorithm table filename ?SEPARATOR? ?NULLINDICATOR?
  **
  ** Copy data into table from filename, optionally using SEPARATOR
  ** as column separators.  If a column contains a null string, or the
  ** value of NULLINDICATOR, a NULL is inserted for the column.
  ** conflict-algorithm is one of the sqlite conflict algorithms:
  **    rollback, abort, fail, ignore, replace
  ** On success, return the number of lines processed, not necessarily same
  ** as 'db changes' due to conflict-algorithm selected.
  **
  ** This code is basically an implementation/enhancement of
  ** the sqlite3 shell.c ".import" command.
  **
  ** This command usage is equivalent to the sqlite2.x COPY statement,
  ** which imports file data into a table using the PostgreSQL COPY file format:
  **   $db copy $conflit_algo $table_name $filename \t \\N
  */
  case DB_COPY: {
    char *zTable;               /* Insert data into this table */
    char *zFile;                /* The file from which to extract data */
    char *zConflict;            /* The conflict algorithm to use */
    sqlite3_stmt *pStmt;        /* A statement */
    int nCol;                   /* Number of columns in the table */
    int nByte;                  /* Number of bytes in an SQL string */
    int i, j;                   /* Loop counters */
    int nSep;                   /* Number of bytes in zSep[] */
    int nNull;                  /* Number of bytes in zNull[] */
    char *zSql;                 /* An SQL statement */
    char *zLine;                /* A single line of input from the file */
    char **azCol;               /* zLine[] broken up into columns */
    char *zCommit;              /* How to commit changes */
    FILE *in;                   /* The input file */
    int lineno = 0;             /* Line number of input file */
    char zLineNum[80];          /* Line number print buffer */
    Tcl_Obj *pResult;           /* interp result */

    char *zSep;
    char *zNull;
    if( objc<5 || objc>7 ){
      Tcl_WrongNumArgs(interp, 2, objv, 
         "CONFLICT-ALGORITHM TABLE FILENAME ?SEPARATOR? ?NULLINDICATOR?");
      return TCL_ERROR;
    }
    if( objc>=6 ){
      zSep = Tcl_GetStringFromObj(objv[5], 0);
    }else{
      zSep = "\t";
    }
    if( objc>=7 ){
      zNull = Tcl_GetStringFromObj(objv[6], 0);
    }else{
      zNull = "";
    }
    zConflict = Tcl_GetStringFromObj(objv[2], 0);
    zTable = Tcl_GetStringFromObj(objv[3], 0);
    zFile = Tcl_GetStringFromObj(objv[4], 0);
    nSep = strlen30(zSep);
    nNull = strlen30(zNull);
    if( nSep==0 ){
      Tcl_AppendResult(interp,"Error: non-null separator required for copy",0);
      return TCL_ERROR;
    }
    if(strcmp(zConflict, "rollback") != 0 &&
       strcmp(zConflict, "abort"   ) != 0 &&
       strcmp(zConflict, "fail"    ) != 0 &&
       strcmp(zConflict, "ignore"  ) != 0 &&
       strcmp(zConflict, "replace" ) != 0 ) {
      Tcl_AppendResult(interp, "Error: \"", zConflict, 
            "\", conflict-algorithm must be one of: rollback, "
            "abort, fail, ignore, or replace", 0);
      return TCL_ERROR;
    }
    zSql = sqlite3_mprintf("SELECT * FROM '%q'", zTable);
    if( zSql==0 ){
      Tcl_AppendResult(interp, "Error: no such table: ", zTable, 0);
      return TCL_ERROR;
    }
    nByte = strlen30(zSql);
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    sqlite3_free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), 0);
      nCol = 0;
    }else{
      nCol = sqlite3_column_count(pStmt);
    }
    sqlite3_finalize(pStmt);
    if( nCol==0 ) {
      return TCL_ERROR;
    }
    zSql = malloc( nByte + 50 + nCol*2 );
    if( zSql==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", 0);
      return TCL_ERROR;
    }
    sqlite3_snprintf(nByte+50, zSql, "INSERT OR %q INTO '%q' VALUES(?",
         zConflict, zTable);
    j = strlen30(zSql);
    for(i=1; i<nCol; i++){
      zSql[j++] = ',';
      zSql[j++] = '?';
    }
    zSql[j++] = ')';
    zSql[j] = 0;
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), 0);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    in = fopen(zFile, "rb");
    if( in==0 ){
      Tcl_AppendResult(interp, "Error: cannot open file: ", zFile, NULL);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    azCol = malloc( sizeof(azCol[0])*(nCol+1) );
    if( azCol==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", 0);
      fclose(in);
      return TCL_ERROR;
    }
    (void)sqlite3_exec(pDb->db, "BEGIN", 0, 0, 0);
    zCommit = "COMMIT";
    while( (zLine = local_getline(0, in))!=0 ){
      char *z;
      i = 0;
      lineno++;
      azCol[0] = zLine;
      for(i=0, z=zLine; *z; z++){
        if( *z==zSep[0] && strncmp(z, zSep, nSep)==0 ){
          *z = 0;
          i++;
          if( i<nCol ){
            azCol[i] = &z[nSep];
            z += nSep-1;
          }
        }
      }
      if( i+1!=nCol ){
        char *zErr;
        int nErr = strlen30(zFile) + 200;
        zErr = malloc(nErr);
        if( zErr ){
          sqlite3_snprintf(nErr, zErr,
             "Error: %s line %d: expected %d columns of data but found %d",
             zFile, lineno, nCol, i+1);
          Tcl_AppendResult(interp, zErr, 0);
          free(zErr);
        }
        zCommit = "ROLLBACK";
        break;
      }
      for(i=0; i<nCol; i++){
        /* check for null data, if so, bind as null */
        if( (nNull>0 && strcmp(azCol[i], zNull)==0)
          || strlen30(azCol[i])==0 
        ){
          sqlite3_bind_null(pStmt, i+1);
        }else{
          sqlite3_bind_text(pStmt, i+1, azCol[i], -1, SQLITE_STATIC);
        }
      }
      sqlite3_step(pStmt);
      rc = sqlite3_reset(pStmt);
      free(zLine);
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp,"Error: ", sqlite3_errmsg(pDb->db), 0);
        zCommit = "ROLLBACK";
        break;
      }
    }
    free(azCol);
    fclose(in);
    sqlite3_finalize(pStmt);
    (void)sqlite3_exec(pDb->db, zCommit, 0, 0, 0);

    if( zCommit[0] == 'C' ){
      /* success, set result as number of lines processed */
      pResult = Tcl_GetObjResult(interp);
      Tcl_SetIntObj(pResult, lineno);
      rc = TCL_OK;
    }else{
      /* failure, append lineno where failed */
      sqlite3_snprintf(sizeof(zLineNum), zLineNum,"%d",lineno);
      Tcl_AppendResult(interp,", failed while processing line: ",zLineNum,0);
      rc = TCL_ERROR;
    }
    break;
  }

  /*
  **    $db enable_load_extension BOOLEAN
  **
  ** Turn the extension loading feature on or off.  It if off by
  ** default.
  */
  case DB_ENABLE_LOAD_EXTENSION: {
#ifndef SQLITE_OMIT_LOAD_EXTENSION
    int onoff;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "BOOLEAN");
      return TCL_ERROR;
    }
    if( Tcl_GetBooleanFromObj(interp, objv[2], &onoff) ){
      return TCL_ERROR;
    }
    sqlite3_enable_load_extension(pDb->db, onoff);
    break;
#else
    Tcl_AppendResult(interp, "extension loading is turned off at compile-time",
                     0);
    return TCL_ERROR;
#endif
  }

  /*
  **    $db errorcode
  **
  ** Return the numeric error code that was returned by the most recent
  ** call to sqlite3_exec().
  */
  case DB_ERRORCODE: {
    Tcl_SetObjResult(interp, Tcl_NewIntObj(sqlite3_errcode(pDb->db)));
    break;
  }

  /*
  **    $db exists $sql
  **    $db onecolumn $sql
  **
  ** The onecolumn method is the equivalent of:
  **     lindex [$db eval $sql] 0
  */
  case DB_EXISTS: 
  case DB_ONECOLUMN: {
    DbEvalContext sEval;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "SQL");
      return TCL_ERROR;
    }

    dbEvalInit(&sEval, pDb, objv[2], 0);
    rc = dbEvalStep(&sEval);
    if( choice==DB_ONECOLUMN ){
      if( rc==TCL_OK ){
        Tcl_SetObjResult(interp, dbEvalColumnValue(&sEval, 0));
      }
    }else if( rc==TCL_BREAK || rc==TCL_OK ){
      Tcl_SetObjResult(interp, Tcl_NewBooleanObj(rc==TCL_OK));
    }
    dbEvalFinalize(&sEval);

    if( rc==TCL_BREAK ){
      rc = TCL_OK;
    }
    break;
  }
   
  /*
  **    $db eval $sql ?array? ?{  ...code... }?
  **
  ** The SQL statement in $sql is evaluated.  For each row, the values are
  ** placed in elements of the array named "array" and ...code... is executed.
  ** If "array" and "code" are omitted, then no callback is every invoked.
  ** If "array" is an empty string, then the values are placed in variables
  ** that have the same name as the fields extracted by the query.
  */
  case DB_EVAL: {
    if( objc<3 || objc>5 ){
      Tcl_WrongNumArgs(interp, 2, objv, "SQL ?ARRAY-NAME? ?SCRIPT?");
      return TCL_ERROR;
    }

    if( objc==3 ){
      DbEvalContext sEval;
      Tcl_Obj *pRet = Tcl_NewObj();
      Tcl_IncrRefCount(pRet);
      dbEvalInit(&sEval, pDb, objv[2], 0);
      while( TCL_OK==(rc = dbEvalStep(&sEval)) ){
        int i;
        int nCol;
        dbEvalRowInfo(&sEval, &nCol, 0);
        for(i=0; i<nCol; i++){
          Tcl_ListObjAppendElement(interp, pRet, dbEvalColumnValue(&sEval, i));
        }
      }
      dbEvalFinalize(&sEval);
      if( rc==TCL_BREAK ){
        Tcl_SetObjResult(interp, pRet);
        rc = TCL_OK;
      }
      Tcl_DecrRefCount(pRet);
    }else{
      ClientData cd[2];
      DbEvalContext *p;
      Tcl_Obj *pArray = 0;
      Tcl_Obj *pScript;

      if( objc==5 && *(char *)Tcl_GetString(objv[3]) ){
        pArray = objv[3];
      }
      pScript = objv[objc-1];
      Tcl_IncrRefCount(pScript);
      
      p = (DbEvalContext *)Tcl_Alloc(sizeof(DbEvalContext));
      dbEvalInit(p, pDb, objv[2], pArray);

      cd[0] = (void *)p;
      cd[1] = (void *)pScript;
      rc = DbEvalNextCmd(cd, interp, TCL_OK);
    }
    break;
  }

  /*
  **     $db function NAME [-argcount N] SCRIPT
  **
  ** Create a new SQL function called NAME.  Whenever that function is
  ** called, invoke SCRIPT to evaluate the function.
  */
  case DB_FUNCTION: {
    SqlFunc *pFunc;
    Tcl_Obj *pScript;
    char *zName;
    int nArg = -1;
    if( objc==6 ){
      const char *z = Tcl_GetString(objv[3]);
      int n = strlen30(z);
      if( n>2 && strncmp(z, "-argcount",n)==0 ){
        if( Tcl_GetIntFromObj(interp, objv[4], &nArg) ) return TCL_ERROR;
        if( nArg<0 ){
          Tcl_AppendResult(interp, "number of arguments must be non-negative",
                           (char*)0);
          return TCL_ERROR;
        }
      }
      pScript = objv[5];
    }else if( objc!=4 ){
      Tcl_WrongNumArgs(interp, 2, objv, "NAME [-argcount N] SCRIPT");
      return TCL_ERROR;
    }else{
      pScript = objv[3];
    }
    zName = Tcl_GetStringFromObj(objv[2], 0);
    pFunc = findSqlFunc(pDb, zName);
    if( pFunc==0 ) return TCL_ERROR;
    if( pFunc->pScript ){
      Tcl_DecrRefCount(pFunc->pScript);
    }
    pFunc->pScript = pScript;
    Tcl_IncrRefCount(pScript);
    pFunc->useEvalObjv = safeToUseEvalObjv(interp, pScript);
    rc = sqlite3_create_function(pDb->db, zName, nArg, SQLITE_UTF8,
        pFunc, tclSqlFunc, 0, 0);
    if( rc!=SQLITE_OK ){
      rc = TCL_ERROR;
      Tcl_SetResult(interp, (char *)sqlite3_errmsg(pDb->db), TCL_VOLATILE);
    }
    break;
  }

  /*
  **     $db incrblob ?-readonly? ?DB? TABLE COLUMN ROWID
  */
  case DB_INCRBLOB: {
#ifdef SQLITE_OMIT_INCRBLOB
    Tcl_AppendResult(interp, "incrblob not available in this build", 0);
    return TCL_ERROR;
#else
    int isReadonly = 0;
    const char *zDb = "main";
    const char *zTable;
    const char *zColumn;
    sqlite_int64 iRow;

    /* Check for the -readonly option */
    if( objc>3 && strcmp(Tcl_GetString(objv[2]), "-readonly")==0 ){
      isReadonly = 1;
    }

    if( objc!=(5+isReadonly) && objc!=(6+isReadonly) ){
      Tcl_WrongNumArgs(interp, 2, objv, "?-readonly? ?DB? TABLE COLUMN ROWID");
      return TCL_ERROR;
    }

    if( objc==(6+isReadonly) ){
      zDb = Tcl_GetString(objv[2]);
    }
    zTable = Tcl_GetString(objv[objc-3]);
    zColumn = Tcl_GetString(objv[objc-2]);
    rc = Tcl_GetWideIntFromObj(interp, objv[objc-1], &iRow);

    if( rc==TCL_OK ){
      rc = createIncrblobChannel(
          interp, pDb, zDb, zTable, zColumn, iRow, isReadonly
      );
    }
#endif
    break;
  }

  /*
  **     $db interrupt
  **
  ** Interrupt the execution of the inner-most SQL interpreter.  This
  ** causes the SQL statement to return an error of SQLITE_INTERRUPT.
  */
  case DB_INTERRUPT: {
    sqlite3_interrupt(pDb->db);
    break;
  }

  /*
  **     $db nullvalue ?STRING?
  **
  ** Change text used when a NULL comes back from the database. If ?STRING?
  ** is not present, then the current string used for NULL is returned.
  ** If STRING is present, then STRING is returned.
  **
  */
  case DB_NULLVALUE: {
    if( objc!=2 && objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "NULLVALUE");
      return TCL_ERROR;
    }
    if( objc==3 ){
      int len;
      char *zNull = Tcl_GetStringFromObj(objv[2], &len);
      if( pDb->zNull ){
        Tcl_Free(pDb->zNull);
      }
      if( zNull && len>0 ){
        pDb->zNull = Tcl_Alloc( len + 1 );
        strncpy(pDb->zNull, zNull, len);
        pDb->zNull[len] = '\0';
      }else{
        pDb->zNull = 0;
      }
    }
    Tcl_SetObjResult(interp, dbTextToObj(pDb->zNull));
    break;
  }

  /*
  **     $db last_insert_rowid 
  **
  ** Return an integer which is the ROWID for the most recent insert.
  */
  case DB_LAST_INSERT_ROWID: {
    Tcl_Obj *pResult;
    Tcl_WideInt rowid;
    if( objc!=2 ){
      Tcl_WrongNumArgs(interp, 2, objv, "");
      return TCL_ERROR;
    }
    rowid = sqlite3_last_insert_rowid(pDb->db);
    pResult = Tcl_GetObjResult(interp);
    Tcl_SetWideIntObj(pResult, rowid);
    break;
  }

  /*
  ** The DB_ONECOLUMN method is implemented together with DB_EXISTS.
  */

  /*    $db progress ?N CALLBACK?
  ** 
  ** Invoke the given callback every N virtual machine opcodes while executing
  ** queries.
  */
  case DB_PROGRESS: {
    if( objc==2 ){
      if( pDb->zProgress ){
        Tcl_AppendResult(interp, pDb->zProgress, 0);
      }
    }else if( objc==4 ){
      char *zProgress;
      int len;
      int N;
      if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &N) ){
        return TCL_ERROR;
      };
      if( pDb->zProgress ){
        Tcl_Free(pDb->zProgress);
      }
      zProgress = Tcl_GetStringFromObj(objv[3], &len);
      if( zProgress && len>0 ){
        pDb->zProgress = Tcl_Alloc( len + 1 );
        memcpy(pDb->zProgress, zProgress, len+1);
      }else{
        pDb->zProgress = 0;
      }
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
      if( pDb->zProgress ){
        pDb->interp = interp;
        sqlite3_progress_handler(pDb->db, N, DbProgressHandler, pDb);
      }else{
        sqlite3_progress_handler(pDb->db, 0, 0, 0);
      }
#endif
    }else{
      Tcl_WrongNumArgs(interp, 2, objv, "N CALLBACK");
      return TCL_ERROR;
    }
    break;
  }

  /*    $db profile ?CALLBACK?
  **
  ** Make arrangements to invoke the CALLBACK routine after each SQL statement
  ** that has run.  The text of the SQL and the amount of elapse time are
  ** appended to CALLBACK before the script is run.
  */
  case DB_PROFILE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zProfile ){
        Tcl_AppendResult(interp, pDb->zProfile, 0);
      }
    }else{
      char *zProfile;
      int len;
      if( pDb->zProfile ){
        Tcl_Free(pDb->zProfile);
      }
      zProfile = Tcl_GetStringFromObj(objv[2], &len);
      if( zProfile && len>0 ){
        pDb->zProfile = Tcl_Alloc( len + 1 );
        memcpy(pDb->zProfile, zProfile, len+1);
      }else{
        pDb->zProfile = 0;
      }
#if !defined(SQLITE_OMIT_TRACE) && !defined(SQLITE_OMIT_FLOATING_POINT)
      if( pDb->zProfile ){
        pDb->interp = interp;
        sqlite3_profile(pDb->db, DbProfileHandler, pDb);
      }else{
        sqlite3_profile(pDb->db, 0, 0);
      }
#endif
    }
    break;
  }

  /*
  **     $db rekey KEY
  **
  ** Change the encryption key on the currently open database.
  */
  case DB_REKEY: {
    int nKey;
    void *pKey;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "KEY");
      return TCL_ERROR;
    }
    pKey = Tcl_GetByteArrayFromObj(objv[2], &nKey);
#ifdef SQLITE_HAS_CODEC
    rc = sqlite3_rekey(pDb->db, pKey, nKey);
    if( rc ){
      Tcl_AppendResult(interp, sqlite3ErrStr(rc), 0);
      rc = TCL_ERROR;
    }
#endif
    break;
  }

  /*    $db restore ?DATABASE? FILENAME
  **
  ** Open a database file named FILENAME.  Transfer the content 
  ** of FILENAME into the local database DATABASE (default: "main").
  */
  case DB_RESTORE: {
    const char *zSrcFile;
    const char *zDestDb;
    sqlite3 *pSrc;
    sqlite3_backup *pBackup;
    int nTimeout = 0;

    if( objc==3 ){
      zDestDb = "main";
      zSrcFile = Tcl_GetString(objv[2]);
    }else if( objc==4 ){
      zDestDb = Tcl_GetString(objv[2]);
      zSrcFile = Tcl_GetString(objv[3]);
    }else{
      Tcl_WrongNumArgs(interp, 2, objv, "?DATABASE? FILENAME");
      return TCL_ERROR;
    }
    rc = sqlite3_open_v2(zSrcFile, &pSrc, SQLITE_OPEN_READONLY, 0);
    if( rc!=SQLITE_OK ){
      Tcl_AppendResult(interp, "cannot open source database: ",
           sqlite3_errmsg(pSrc), (char*)0);
      sqlite3_close(pSrc);
      return TCL_ERROR;
    }
    pBackup = sqlite3_backup_init(pDb->db, zDestDb, pSrc, "main");
    if( pBackup==0 ){
      Tcl_AppendResult(interp, "restore failed: ",
           sqlite3_errmsg(pDb->db), (char*)0);
      sqlite3_close(pSrc);
      return TCL_ERROR;
    }
    while( (rc = sqlite3_backup_step(pBackup,100))==SQLITE_OK
              || rc==SQLITE_BUSY ){
      if( rc==SQLITE_BUSY ){
        if( nTimeout++ >= 3 ) break;
        sqlite3_sleep(100);
      }
    }
    sqlite3_backup_finish(pBackup);
    if( rc==SQLITE_DONE ){
      rc = TCL_OK;
    }else if( rc==SQLITE_BUSY || rc==SQLITE_LOCKED ){
      Tcl_AppendResult(interp, "restore failed: source database busy",
                       (char*)0);
      rc = TCL_ERROR;
    }else{
      Tcl_AppendResult(interp, "restore failed: ",
           sqlite3_errmsg(pDb->db), (char*)0);
      rc = TCL_ERROR;
    }
    sqlite3_close(pSrc);
    break;
  }

  /*
  **     $db status (step|sort|autoindex)
  **
  ** Display SQLITE_STMTSTATUS_FULLSCAN_STEP or 
  ** SQLITE_STMTSTATUS_SORT for the most recent eval.
  */
  case DB_STATUS: {
    int v;
    const char *zOp;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "(step|sort|autoindex)");
      return TCL_ERROR;
    }
    zOp = Tcl_GetString(objv[2]);
    if( strcmp(zOp, "step")==0 ){
      v = pDb->nStep;
    }else if( strcmp(zOp, "sort")==0 ){
      v = pDb->nSort;
    }else if( strcmp(zOp, "autoindex")==0 ){
      v = pDb->nIndex;
    }else{
      Tcl_AppendResult(interp, 
            "bad argument: should be autoindex, step, or sort", 
            (char*)0);
      return TCL_ERROR;
    }
    Tcl_SetObjResult(interp, Tcl_NewIntObj(v));
    break;
  }
  
  /*
  **     $db timeout MILLESECONDS
  **
  ** Delay for the number of milliseconds specified when a file is locked.
  */
  case DB_TIMEOUT: {
    int ms;
    if( objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "MILLISECONDS");
      return TCL_ERROR;
    }
    if( Tcl_GetIntFromObj(interp, objv[2], &ms) ) return TCL_ERROR;
    sqlite3_busy_timeout(pDb->db, ms);
    break;
  }
  
  /*
  **     $db total_changes
  **
  ** Return the number of rows that were modified, inserted, or deleted 
  ** since the database handle was created.
  */
  case DB_TOTAL_CHANGES: {
    Tcl_Obj *pResult;
    if( objc!=2 ){
      Tcl_WrongNumArgs(interp, 2, objv, "");
      return TCL_ERROR;
    }
    pResult = Tcl_GetObjResult(interp);
    Tcl_SetIntObj(pResult, sqlite3_total_changes(pDb->db));
    break;
  }

  /*    $db trace ?CALLBACK?
  **
  ** Make arrangements to invoke the CALLBACK routine for each SQL statement
  ** that is executed.  The text of the SQL is appended to CALLBACK before
  ** it is executed.
  */
  case DB_TRACE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zTrace ){
        Tcl_AppendResult(interp, pDb->zTrace, 0);
      }
    }else{
      char *zTrace;
      int len;
      if( pDb->zTrace ){
        Tcl_Free(pDb->zTrace);
      }
      zTrace = Tcl_GetStringFromObj(objv[2], &len);
      if( zTrace && len>0 ){
        pDb->zTrace = Tcl_Alloc( len + 1 );
        memcpy(pDb->zTrace, zTrace, len+1);
      }else{
        pDb->zTrace = 0;
      }
#if !defined(SQLITE_OMIT_TRACE) && !defined(SQLITE_OMIT_FLOATING_POINT)
      if( pDb->zTrace ){
        pDb->interp = interp;
        sqlite3_trace(pDb->db, DbTraceHandler, pDb);
      }else{
        sqlite3_trace(pDb->db, 0, 0);
      }
#endif
    }
    break;
  }

  /*    $db transaction [-deferred|-immediate|-exclusive] SCRIPT
  **
  ** Start a new transaction (if we are not already in the midst of a
  ** transaction) and execute the TCL script SCRIPT.  After SCRIPT
  ** completes, either commit the transaction or roll it back if SCRIPT
  ** throws an exception.  Or if no new transation was started, do nothing.
  ** pass the exception on up the stack.
  **
  ** This command was inspired by Dave Thomas's talk on Ruby at the
  ** 2005 O'Reilly Open Source Convention (OSCON).
  */
  case DB_TRANSACTION: {
    Tcl_Obj *pScript;
    const char *zBegin = "SAVEPOINT _tcl_transaction";
    if( objc!=3 && objc!=4 ){
      Tcl_WrongNumArgs(interp, 2, objv, "[TYPE] SCRIPT");
      return TCL_ERROR;
    }

    if( pDb->nTransaction==0 && objc==4 ){
      static const char *TTYPE_strs[] = {
        "deferred",   "exclusive",  "immediate", 0
      };
      enum TTYPE_enum {
        TTYPE_DEFERRED, TTYPE_EXCLUSIVE, TTYPE_IMMEDIATE
      };
      int ttype;
      if( Tcl_GetIndexFromObj(interp, objv[2], TTYPE_strs, "transaction type",
                              0, &ttype) ){
        return TCL_ERROR;
      }
      switch( (enum TTYPE_enum)ttype ){
        case TTYPE_DEFERRED:    /* no-op */;                 break;
        case TTYPE_EXCLUSIVE:   zBegin = "BEGIN EXCLUSIVE";  break;
        case TTYPE_IMMEDIATE:   zBegin = "BEGIN IMMEDIATE";  break;
      }
    }
    pScript = objv[objc-1];

    /* Run the SQLite BEGIN command to open a transaction or savepoint. */
    pDb->disableAuth++;
    rc = sqlite3_exec(pDb->db, zBegin, 0, 0, 0);
    pDb->disableAuth--;
    if( rc!=SQLITE_OK ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
      return TCL_ERROR;
    }
    pDb->nTransaction++;

    /* If using NRE, schedule a callback to invoke the script pScript, then
    ** a second callback to commit (or rollback) the transaction or savepoint
    ** opened above. If not using NRE, evaluate the script directly, then
    ** call function DbTransPostCmd() to commit (or rollback) the transaction 
    ** or savepoint.  */
    if( DbUseNre() ){
      Tcl_NRAddCallback(interp, DbTransPostCmd, cd, 0, 0, 0);
      Tcl_NREvalObj(interp, pScript, 0);
    }else{
      rc = DbTransPostCmd(&cd, interp, Tcl_EvalObjEx(interp, pScript, 0));
    }
    break;
  }

  /*
  **    $db unlock_notify ?script?
  */
  case DB_UNLOCK_NOTIFY: {
#ifndef SQLITE_ENABLE_UNLOCK_NOTIFY
    Tcl_AppendResult(interp, "unlock_notify not available in this build", 0);
    rc = TCL_ERROR;
#else
    if( objc!=2 && objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
      rc = TCL_ERROR;
    }else{
      void (*xNotify)(void **, int) = 0;
      void *pNotifyArg = 0;

      if( pDb->pUnlockNotify ){
        Tcl_DecrRefCount(pDb->pUnlockNotify);
        pDb->pUnlockNotify = 0;
      }
  
      if( objc==3 ){
        xNotify = DbUnlockNotify;
        pNotifyArg = (void *)pDb;
        pDb->pUnlockNotify = objv[2];
        Tcl_IncrRefCount(pDb->pUnlockNotify);
      }
  
      if( sqlite3_unlock_notify(pDb->db, xNotify, pNotifyArg) ){
        Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
        rc = TCL_ERROR;
      }
    }
#endif
    break;
  }

  /*
  **    $db wal_hook ?script?
  **    $db update_hook ?script?
  **    $db rollback_hook ?script?
  */
  case DB_WAL_HOOK: 
  case DB_UPDATE_HOOK: 
  case DB_ROLLBACK_HOOK: {

    /* set ppHook to point at pUpdateHook or pRollbackHook, depending on 
    ** whether [$db update_hook] or [$db rollback_hook] was invoked.
    */
    Tcl_Obj **ppHook; 
    if( choice==DB_UPDATE_HOOK ){
      ppHook = &pDb->pUpdateHook;
    }else if( choice==DB_WAL_HOOK ){
      ppHook = &pDb->pWalHook;
    }else{
      ppHook = &pDb->pRollbackHook;
    }

    if( objc!=2 && objc!=3 ){
       Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
       return TCL_ERROR;
    }
    if( *ppHook ){
      Tcl_SetObjResult(interp, *ppHook);
      if( objc==3 ){
        Tcl_DecrRefCount(*ppHook);
        *ppHook = 0;
      }
    }
    if( objc==3 ){
      assert( !(*ppHook) );
      if( Tcl_GetCharLength(objv[2])>0 ){
        *ppHook = objv[2];
        Tcl_IncrRefCount(*ppHook);
      }
    }

    sqlite3_update_hook(pDb->db, (pDb->pUpdateHook?DbUpdateHandler:0), pDb);
    sqlite3_rollback_hook(pDb->db,(pDb->pRollbackHook?DbRollbackHandler:0),pDb);
    sqlite3_wal_hook(pDb->db,(pDb->pWalHook?DbWalHandler:0),pDb);

    break;
  }

  /*    $db version
  **
  ** Return the version string for this database.
  */
  case DB_VERSION: {
    Tcl_SetResult(interp, (char *)sqlite3_libversion(), TCL_STATIC);
    break;
  }


  } /* End of the SWITCH statement */
  return rc;
}

#if SQLITE_TCL_NRE
/*
** Adaptor that provides an objCmd interface to the NRE-enabled
** interface implementation.
*/
static int DbObjCmdAdaptor(
  void *cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *const*objv
){
  return Tcl_NRCallObjProc(interp, DbObjCmd, cd, objc, objv);
}
#endif /* SQLITE_TCL_NRE */

/*
**   sqlite3 DBNAME FILENAME ?-vfs VFSNAME? ?-key KEY? ?-readonly BOOLEAN?
**                           ?-create BOOLEAN? ?-nomutex BOOLEAN?
**
** This is the main Tcl command.  When the "sqlite" Tcl command is
** invoked, this routine runs to process that command.
**
** The first argument, DBNAME, is an arbitrary name for a new
** database connection.  This command creates a new command named
** DBNAME that is used to control that connection.  The database
** connection is deleted when the DBNAME command is deleted.
**
** The second argument is the name of the database file.
**
*/
static int DbMain(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
  SqliteDb *p;
  void *pKey = 0;
  int nKey = 0;
  const char *zArg;
  char *zErrMsg;
  int i;
  const char *zFile;
  const char *zVfs = 0;
  int flags;
  Tcl_DString translatedFilename;

  /* In normal use, each TCL interpreter runs in a single thread.  So
  ** by default, we can turn of mutexing on SQLite database connections.
  ** However, for testing purposes it is useful to have mutexes turned
  ** on.  So, by default, mutexes default off.  But if compiled with
  ** SQLITE_TCL_DEFAULT_FULLMUTEX then mutexes default on.
  */
#ifdef SQLITE_TCL_DEFAULT_FULLMUTEX
  flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX;
#else
  flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_NOMUTEX;
#endif

  if( objc==2 ){
    zArg = Tcl_GetStringFromObj(objv[1], 0);
    if( strcmp(zArg,"-version")==0 ){
      Tcl_AppendResult(interp,sqlite3_version,0);
      return TCL_OK;
    }
    if( strcmp(zArg,"-has-codec")==0 ){
#ifdef SQLITE_HAS_CODEC
      Tcl_AppendResult(interp,"1",0);
#else
      Tcl_AppendResult(interp,"0",0);
#endif
      return TCL_OK;
    }
  }
  for(i=3; i+1<objc; i+=2){
    zArg = Tcl_GetString(objv[i]);
    if( strcmp(zArg,"-key")==0 ){
      pKey = Tcl_GetByteArrayFromObj(objv[i+1], &nKey);
    }else if( strcmp(zArg, "-vfs")==0 ){
      zVfs = Tcl_GetString(objv[i+1]);
    }else if( strcmp(zArg, "-readonly")==0 ){
      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
        flags |= SQLITE_OPEN_READONLY;
      }else{
        flags &= ~SQLITE_OPEN_READONLY;
        flags |= SQLITE_OPEN_READWRITE;
      }
    }else if( strcmp(zArg, "-create")==0 ){
      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b && (flags & SQLITE_OPEN_READONLY)==0 ){
        flags |= SQLITE_OPEN_CREATE;
      }else{
        flags &= ~SQLITE_OPEN_CREATE;
      }
    }else if( strcmp(zArg, "-nomutex")==0 ){
      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags |= SQLITE_OPEN_NOMUTEX;
        flags &= ~SQLITE_OPEN_FULLMUTEX;
      }else{
        flags &= ~SQLITE_OPEN_NOMUTEX;
      }
   }else if( strcmp(zArg, "-fullmutex")==0 ){
      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags |= SQLITE_OPEN_FULLMUTEX;
        flags &= ~SQLITE_OPEN_NOMUTEX;
      }else{
        flags &= ~SQLITE_OPEN_FULLMUTEX;
      }
    }else{
      Tcl_AppendResult(interp, "unknown option: ", zArg, (char*)0);
      return TCL_ERROR;
    }
  }
  if( objc<3 || (objc&1)!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, 
      "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN?"
#ifdef SQLITE_HAS_CODEC
      " ?-key CODECKEY?"
#endif
    );
    return TCL_ERROR;
  }
  zErrMsg = 0;
  p = (SqliteDb*)Tcl_Alloc( sizeof(*p) );
  if( p==0 ){
    Tcl_SetResult(interp, "malloc failed", TCL_STATIC);
    return TCL_ERROR;
  }
  memset(p, 0, sizeof(*p));
  zFile = Tcl_GetStringFromObj(objv[2], 0);
  zFile = Tcl_TranslateFileName(interp, zFile, &translatedFilename);
  sqlite3_open_v2(zFile, &p->db, flags, zVfs);
  Tcl_DStringFree(&translatedFilename);
  if( SQLITE_OK!=sqlite3_errcode(p->db) ){
    zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(p->db));
    sqlite3_close(p->db);
    p->db = 0;
  }
#ifdef SQLITE_HAS_CODEC
  if( p->db ){
    sqlite3_key(p->db, pKey, nKey);
  }
#endif
  if( p->db==0 ){
    Tcl_SetResult(interp, zErrMsg, TCL_VOLATILE);
    Tcl_Free((char*)p);
    sqlite3_free(zErrMsg);
    return TCL_ERROR;
  }
  p->maxStmt = NUM_PREPARED_STMTS;
  p->interp = interp;
  zArg = Tcl_GetStringFromObj(objv[1], 0);
  if( DbUseNre() ){
    Tcl_NRCreateCommand(interp, zArg, DbObjCmdAdaptor, DbObjCmd,
                        (char*)p, DbDeleteCmd);
  }else{
    Tcl_CreateObjCommand(interp, zArg, DbObjCmd, (char*)p, DbDeleteCmd);
  }
  return TCL_OK;
}

/*
** Provide a dummy Tcl_InitStubs if we are using this as a static
** library.
*/
#ifndef USE_TCL_STUBS
# undef  Tcl_InitStubs
# define Tcl_InitStubs(a,b,c)
#endif

/*
** Make sure we have a PACKAGE_VERSION macro defined.  This will be
** defined automatically by the TEA makefile.  But other makefiles
** do not define it.
*/
#ifndef PACKAGE_VERSION
# define PACKAGE_VERSION SQLITE_VERSION
#endif

/*
** Initialize this module.
**
** This Tcl module contains only a single new Tcl command named "sqlite".
** (Hence there is no namespace.  There is no point in using a namespace
** if the extension only supplies one new name!)  The "sqlite" command is
** used to open a new SQLite database.  See the DbMain() routine above
** for additional information.
**
** The EXTERN macros are required by TCL in order to work on windows.
*/
EXTERN int Sqlite3_Init(Tcl_Interp *interp){
  Tcl_InitStubs(interp, "8.4", 0);
  Tcl_CreateObjCommand(interp, "sqlite3", (Tcl_ObjCmdProc*)DbMain, 0, 0);
  Tcl_PkgProvide(interp, "sqlite3", PACKAGE_VERSION);

#ifndef SQLITE_3_SUFFIX_ONLY
  /* The "sqlite" alias is undocumented.  It is here only to support
  ** legacy scripts.  All new scripts should use only the "sqlite3"
  ** command.
  */
  Tcl_CreateObjCommand(interp, "sqlite", (Tcl_ObjCmdProc*)DbMain, 0, 0);
#endif

  return TCL_OK;
}
EXTERN int Tclsqlite3_Init(Tcl_Interp *interp){ return Sqlite3_Init(interp); }
EXTERN int Sqlite3_SafeInit(Tcl_Interp *interp){ return TCL_OK; }
EXTERN int Tclsqlite3_SafeInit(Tcl_Interp *interp){ return TCL_OK; }
EXTERN int Sqlite3_Unload(Tcl_Interp *interp, int flags){ return TCL_OK; }
EXTERN int Tclsqlite3_Unload(Tcl_Interp *interp, int flags){ return TCL_OK; }
EXTERN int Sqlite3_SafeUnload(Tcl_Interp *interp, int flags){ return TCL_OK; }
EXTERN int Tclsqlite3_SafeUnload(Tcl_Interp *interp, int flags){ return TCL_OK;}


#ifndef SQLITE_3_SUFFIX_ONLY
int Sqlite_Init(Tcl_Interp *interp){ return Sqlite3_Init(interp); }
int Tclsqlite_Init(Tcl_Interp *interp){ return Sqlite3_Init(interp); }
int Sqlite_SafeInit(Tcl_Interp *interp){ return TCL_OK; }
int Tclsqlite_SafeInit(Tcl_Interp *interp){ return TCL_OK; }
int Sqlite_Unload(Tcl_Interp *interp, int flags){ return TCL_OK; }
int Tclsqlite_Unload(Tcl_Interp *interp, int flags){ return TCL_OK; }
int Sqlite_SafeUnload(Tcl_Interp *interp, int flags){ return TCL_OK; }
int Tclsqlite_SafeUnload(Tcl_Interp *interp, int flags){ return TCL_OK;}
#endif

#ifdef TCLSH
/*****************************************************************************
** All of the code that follows is used to build standalone TCL interpreters
** that are statically linked with SQLite.  Enable these by compiling
** with -DTCLSH=n where n can be 1 or 2.  An n of 1 generates a standard
** tclsh but with SQLite built in.  An n of 2 generates the SQLite space
** analysis program.
*/

#if defined(SQLITE_TEST) || defined(SQLITE_TCLMD5)
/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 */

/*
 * If compiled on a machine that doesn't have a 32-bit integer,
 * you just set "uint32" to the appropriate datatype for an
 * unsigned 32-bit integer.  For example:
 *
 *       cc -Duint32='unsigned long' md5.c
 *
 */
#ifndef uint32
#  define uint32 unsigned int
#endif

struct MD5Context {
  int isInit;
  uint32 buf[4];
  uint32 bits[2];
  unsigned char in[64];
};
typedef struct MD5Context MD5Context;

/*
 * Note: this code is harmless on little-endian machines.
 */
static void byteReverse (unsigned char *buf, unsigned longs){
        uint32 t;
        do {
                t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |
                            ((unsigned)buf[1]<<8 | buf[0]);
                *(uint32 *)buf = t;
                buf += 4;
        } while (--longs);
}
/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5Transform(uint32 buf[4], const uint32 in[16]){
        register uint32 a, b, c, d;

        a = buf[0];
        b = buf[1];
        c = buf[2];
        d = buf[3];

        MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
        MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
        MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
        MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
        MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);

        MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
        MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
        MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
        MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
        MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
        MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
        MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
        MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
        MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);

        MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
        MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
        MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
        MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
        MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);

        MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
        MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
        MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
        MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
        MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);

        buf[0] += a;
        buf[1] += b;
        buf[2] += c;
        buf[3] += d;
}

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
static void MD5Init(MD5Context *ctx){
        ctx->isInit = 1;
        ctx->buf[0] = 0x67452301;
        ctx->buf[1] = 0xefcdab89;
        ctx->buf[2] = 0x98badcfe;
        ctx->buf[3] = 0x10325476;
        ctx->bits[0] = 0;
        ctx->bits[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static 
void MD5Update(MD5Context *ctx, const unsigned char *buf, unsigned int len){
        uint32 t;

        /* Update bitcount */

        t = ctx->bits[0];
        if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
                ctx->bits[1]++; /* Carry from low to high */
        ctx->bits[1] += len >> 29;

        t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

        /* Handle any leading odd-sized chunks */

        if ( t ) {
                unsigned char *p = (unsigned char *)ctx->in + t;

                t = 64-t;
                if (len < t) {
                        memcpy(p, buf, len);
                        return;
                }
                memcpy(p, buf, t);
                byteReverse(ctx->in, 16);
                MD5Transform(ctx->buf, (uint32 *)ctx->in);
                buf += t;
                len -= t;
        }

        /* Process data in 64-byte chunks */

        while (len >= 64) {
                memcpy(ctx->in, buf, 64);
                byteReverse(ctx->in, 16);
                MD5Transform(ctx->buf, (uint32 *)ctx->in);
                buf += 64;
                len -= 64;
        }

        /* Handle any remaining bytes of data. */

        memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5Final(unsigned char digest[16], MD5Context *ctx){
        unsigned count;
        unsigned char *p;

        /* Compute number of bytes mod 64 */
        count = (ctx->bits[0] >> 3) & 0x3F;

        /* Set the first char of padding to 0x80.  This is safe since there is
           always at least one byte free */
        p = ctx->in + count;
        *p++ = 0x80;

        /* Bytes of padding needed to make 64 bytes */
        count = 64 - 1 - count;

        /* Pad out to 56 mod 64 */
        if (count < 8) {
                /* Two lots of padding:  Pad the first block to 64 bytes */
                memset(p, 0, count);
                byteReverse(ctx->in, 16);
                MD5Transform(ctx->buf, (uint32 *)ctx->in);

                /* Now fill the next block with 56 bytes */
                memset(ctx->in, 0, 56);
        } else {
                /* Pad block to 56 bytes */
                memset(p, 0, count-8);
        }
        byteReverse(ctx->in, 14);

        /* Append length in bits and transform */
        ((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
        ((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];

        MD5Transform(ctx->buf, (uint32 *)ctx->in);
        byteReverse((unsigned char *)ctx->buf, 4);
        memcpy(digest, ctx->buf, 16);
        memset(ctx, 0, sizeof(ctx));    /* In case it is sensitive */
}

/*
** Convert a 128-bit MD5 digest into a 32-digit base-16 number.
*/
static void MD5DigestToBase16(unsigned char *digest, char *zBuf){
  static char const zEncode[] = "0123456789abcdef";
  int i, j;

  for(j=i=0; i<16; i++){
    int a = digest[i];
    zBuf[j++] = zEncode[(a>>4)&0xf];
    zBuf[j++] = zEncode[a & 0xf];
  }
  zBuf[j] = 0;
}


/*
** Convert a 128-bit MD5 digest into sequency of eight 5-digit integers
** each representing 16 bits of the digest and separated from each
** other by a "-" character.
*/
static void MD5DigestToBase10x8(unsigned char digest[16], char zDigest[50]){
  int i, j;
  unsigned int x;
  for(i=j=0; i<16; i+=2){
    x = digest[i]*256 + digest[i+1];
    if( i>0 ) zDigest[j++] = '-';
    sprintf(&zDigest[j], "%05u", x);
    j += 5;
  }
  zDigest[j] = 0;
}

/*
** A TCL command for md5.  The argument is the text to be hashed.  The
** Result is the hash in base64.  
*/
static int md5_cmd(void*cd, Tcl_Interp *interp, int argc, const char **argv){
  MD5Context ctx;
  unsigned char digest[16];
  char zBuf[50];
  void (*converter)(unsigned char*, char*);

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " TEXT\"", 0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  MD5Update(&ctx, (unsigned char*)argv[1], (unsigned)strlen(argv[1]));
  MD5Final(digest, &ctx);
  converter = (void(*)(unsigned char*,char*))cd;
  converter(digest, zBuf);
  Tcl_AppendResult(interp, zBuf, (char*)0);
  return TCL_OK;
}

/*
** A TCL command to take the md5 hash of a file.  The argument is the
** name of the file.
*/
static int md5file_cmd(void*cd, Tcl_Interp*interp, int argc, const char **argv){
  FILE *in;
  MD5Context ctx;
  void (*converter)(unsigned char*, char*);
  unsigned char digest[16];
  char zBuf[10240];

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " FILENAME\"", 0);
    return TCL_ERROR;
  }
  in = fopen(argv[1],"rb");
  if( in==0 ){
    Tcl_AppendResult(interp,"unable to open file \"", argv[1], 
         "\" for reading", 0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  for(;;){
    int n;
    n = fread(zBuf, 1, sizeof(zBuf), in);
    if( n<=0 ) break;
    MD5Update(&ctx, (unsigned char*)zBuf, (unsigned)n);
  }
  fclose(in);
  MD5Final(digest, &ctx);
  converter = (void(*)(unsigned char*,char*))cd;
  converter(digest, zBuf);
  Tcl_AppendResult(interp, zBuf, (char*)0);
  return TCL_OK;
}

/*
** Register the four new TCL commands for generating MD5 checksums
** with the TCL interpreter.
*/
int Md5_Init(Tcl_Interp *interp){
  Tcl_CreateCommand(interp, "md5", (Tcl_CmdProc*)md5_cmd,
                    MD5DigestToBase16, 0);
  Tcl_CreateCommand(interp, "md5-10x8", (Tcl_CmdProc*)md5_cmd,
                    MD5DigestToBase10x8, 0);
  Tcl_CreateCommand(interp, "md5file", (Tcl_CmdProc*)md5file_cmd,
                    MD5DigestToBase16, 0);
  Tcl_CreateCommand(interp, "md5file-10x8", (Tcl_CmdProc*)md5file_cmd,
                    MD5DigestToBase10x8, 0);
  return TCL_OK;
}
#endif /* defined(SQLITE_TEST) || defined(SQLITE_TCLMD5) */

#if defined(SQLITE_TEST)
/*
** During testing, the special md5sum() aggregate function is available.
** inside SQLite.  The following routines implement that function.
*/
static void md5step(sqlite3_context *context, int argc, sqlite3_value **argv){
  MD5Context *p;
  int i;
  if( argc<1 ) return;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  if( p==0 ) return;
  if( !p->isInit ){
    MD5Init(p);
  }
  for(i=0; i<argc; i++){
    const char *zData = (char*)sqlite3_value_text(argv[i]);
    if( zData ){
      MD5Update(p, (unsigned char*)zData, strlen(zData));
    }
  }
}
static void md5finalize(sqlite3_context *context){
  MD5Context *p;
  unsigned char digest[16];
  char zBuf[33];
  p = sqlite3_aggregate_context(context, sizeof(*p));
  MD5Final(digest,p);
  MD5DigestToBase16(digest, zBuf);
  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
}
int Md5_Register(sqlite3 *db){
  int rc = sqlite3_create_function(db, "md5sum", -1, SQLITE_UTF8, 0, 0, 
                                 md5step, md5finalize);
  sqlite3_overload_function(db, "md5sum", -1);  /* To exercise this API */
  return rc;
}
#endif /* defined(SQLITE_TEST) */


/*
** If the macro TCLSH is one, then put in code this for the
** "main" routine that will initialize Tcl and take input from
** standard input, or if a file is named on the command line
** the TCL interpreter reads and evaluates that file.
*/
#if TCLSH==1
static char zMainloop[] =
  "set line {}\n"
  "while {![eof stdin]} {\n"
    "if {$line!=\"\"} {\n"
      "puts -nonewline \"> \"\n"
    "} else {\n"
      "puts -nonewline \"% \"\n"
    "}\n"
    "flush stdout\n"
    "append line [gets stdin]\n"
    "if {[info complete $line]} {\n"
      "if {[catch {uplevel #0 $line} result]} {\n"
        "puts stderr \"Error: $result\"\n"
      "} elseif {$result!=\"\"} {\n"
        "puts $result\n"
      "}\n"
      "set line {}\n"
    "} else {\n"
      "append line \\n\n"
    "}\n"
  "}\n"
;
#endif
#if TCLSH==2
static char zMainloop[] = 
#include "spaceanal_tcl.h"
;
#endif

#ifdef SQLITE_TEST
static void init_all(Tcl_Interp *);
static int init_all_cmd(
  ClientData cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){

  Tcl_Interp *slave;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SLAVE");
    return TCL_ERROR;
  }

  slave = Tcl_GetSlave(interp, Tcl_GetString(objv[1]));
  if( !slave ){
    return TCL_ERROR;
  }

  init_all(slave);
  return TCL_OK;
}
#endif

/*
** Configure the interpreter passed as the first argument to have access
** to the commands and linked variables that make up:
**
**   * the [sqlite3] extension itself, 
**
**   * If SQLITE_TCLMD5 or SQLITE_TEST is defined, the Md5 commands, and
**
**   * If SQLITE_TEST is set, the various test interfaces used by the Tcl
**     test suite.
*/
static void init_all(Tcl_Interp *interp){
  Sqlite3_Init(interp);

#if defined(SQLITE_TEST) || defined(SQLITE_TCLMD5)
  Md5_Init(interp);
#endif

#ifdef SQLITE_TEST
  {
    extern int Sqliteconfig_Init(Tcl_Interp*);
    extern int Sqlitetest1_Init(Tcl_Interp*);
    extern int Sqlitetest2_Init(Tcl_Interp*);
    extern int Sqlitetest3_Init(Tcl_Interp*);
    extern int Sqlitetest4_Init(Tcl_Interp*);
    extern int Sqlitetest5_Init(Tcl_Interp*);
    extern int Sqlitetest6_Init(Tcl_Interp*);
    extern int Sqlitetest7_Init(Tcl_Interp*);
    extern int Sqlitetest8_Init(Tcl_Interp*);
    extern int Sqlitetest9_Init(Tcl_Interp*);
    extern int Sqlitetestasync_Init(Tcl_Interp*);
    extern int Sqlitetest_autoext_Init(Tcl_Interp*);
    extern int Sqlitetest_demovfs_Init(Tcl_Interp *);
    extern int Sqlitetest_func_Init(Tcl_Interp*);
    extern int Sqlitetest_hexio_Init(Tcl_Interp*);
    extern int Sqlitetest_init_Init(Tcl_Interp*);
    extern int Sqlitetest_malloc_Init(Tcl_Interp*);
    extern int Sqlitetest_mutex_Init(Tcl_Interp*);
    extern int Sqlitetestschema_Init(Tcl_Interp*);
    extern int Sqlitetestsse_Init(Tcl_Interp*);
    extern int Sqlitetesttclvar_Init(Tcl_Interp*);
    extern int SqlitetestThread_Init(Tcl_Interp*);
    extern int SqlitetestOnefile_Init();
    extern int SqlitetestOsinst_Init(Tcl_Interp*);
    extern int Sqlitetestbackup_Init(Tcl_Interp*);
    extern int Sqlitetestintarray_Init(Tcl_Interp*);
    extern int Sqlitetestvfs_Init(Tcl_Interp *);
    extern int SqlitetestStat_Init(Tcl_Interp*);
    extern int Sqlitetestrtree_Init(Tcl_Interp*);
    extern int Sqlitequota_Init(Tcl_Interp*);
    extern int Sqlitemultiplex_Init(Tcl_Interp*);
    extern int SqliteSuperlock_Init(Tcl_Interp*);
    extern int SqlitetestSyscall_Init(Tcl_Interp*);
    extern int Sqlitetestfuzzer_Init(Tcl_Interp*);
    extern int Sqlitetestwholenumber_Init(Tcl_Interp*);

#ifdef SQLITE_ENABLE_ZIPVFS
    extern int Zipvfs_Init(Tcl_Interp*);
    Zipvfs_Init(interp);
#endif

    Sqliteconfig_Init(interp);
    Sqlitetest1_Init(interp);
    Sqlitetest2_Init(interp);
    Sqlitetest3_Init(interp);
    Sqlitetest4_Init(interp);
    Sqlitetest5_Init(interp);
    Sqlitetest6_Init(interp);
    Sqlitetest7_Init(interp);
    Sqlitetest8_Init(interp);
    Sqlitetest9_Init(interp);
    Sqlitetestasync_Init(interp);
    Sqlitetest_autoext_Init(interp);
    Sqlitetest_demovfs_Init(interp);
    Sqlitetest_func_Init(interp);
    Sqlitetest_hexio_Init(interp);
    Sqlitetest_init_Init(interp);
    Sqlitetest_malloc_Init(interp);
    Sqlitetest_mutex_Init(interp);
    Sqlitetestschema_Init(interp);
    Sqlitetesttclvar_Init(interp);
    SqlitetestThread_Init(interp);
    SqlitetestOnefile_Init(interp);
    SqlitetestOsinst_Init(interp);
    Sqlitetestbackup_Init(interp);
    Sqlitetestintarray_Init(interp);
    Sqlitetestvfs_Init(interp);
    SqlitetestStat_Init(interp);
    Sqlitetestrtree_Init(interp);
    Sqlitequota_Init(interp);
    Sqlitemultiplex_Init(interp);
    SqliteSuperlock_Init(interp);
    SqlitetestSyscall_Init(interp);
    Sqlitetestfuzzer_Init(interp);
    Sqlitetestwholenumber_Init(interp);

    Tcl_CreateObjCommand(interp,"load_testfixture_extensions",init_all_cmd,0,0);

#ifdef SQLITE_SSE
    Sqlitetestsse_Init(interp);
#endif
  }
#endif
}

#define TCLSH_MAIN main   /* Needed to fake out mktclapp */
int TCLSH_MAIN(int argc, char **argv){
  Tcl_Interp *interp;
  
  /* Call sqlite3_shutdown() once before doing anything else. This is to
  ** test that sqlite3_shutdown() can be safely called by a process before
  ** sqlite3_initialize() is. */
  sqlite3_shutdown();

#if TCLSH==2
  sqlite3_config(SQLITE_CONFIG_SINGLETHREAD);
#endif
  Tcl_FindExecutable(argv[0]);

  interp = Tcl_CreateInterp();
  init_all(interp);
  if( argc>=2 ){
    int i;
    char zArgc[32];
    sqlite3_snprintf(sizeof(zArgc), zArgc, "%d", argc-(3-TCLSH));
    Tcl_SetVar(interp,"argc", zArgc, TCL_GLOBAL_ONLY);
    Tcl_SetVar(interp,"argv0",argv[1],TCL_GLOBAL_ONLY);
    Tcl_SetVar(interp,"argv", "", TCL_GLOBAL_ONLY);
    for(i=3-TCLSH; i<argc; i++){
      Tcl_SetVar(interp, "argv", argv[i],
          TCL_GLOBAL_ONLY | TCL_LIST_ELEMENT | TCL_APPEND_VALUE);
    }
    if( TCLSH==1 && Tcl_EvalFile(interp, argv[1])!=TCL_OK ){
      const char *zInfo = Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY);
      if( zInfo==0 ) zInfo = Tcl_GetStringResult(interp);
      fprintf(stderr,"%s: %s\n", *argv, zInfo);
      return 1;
    }
  }
  if( TCLSH==2 || argc<=1 ){
    Tcl_GlobalEval(interp, zMainloop);
  }
  return 0;
}
#endif /* TCLSH */