SQLite4  Check-in [f88d080127]

** Called by the parser to compile a DETACH statement.
**
**     DETACH pDbname
*/
void sqlite4Detach(Parse *pParse, Expr *pDbname){
  static const FuncDef detach_func = {
    1,                /* nArg */
    SQLITE4_UTF8,      /* iPrefEnc */
    0,                /* flags */
    0,                /* pUserData */
    0,                /* pNext */
    detachFunc,       /* xFunc */
    0,                /* xStep */
    0,                /* xFinalize */
    "sqlite_detach",  /* zName */

** Called by the parser to compile an ATTACH statement.
**
**     ATTACH p AS pDbname KEY pKey
*/
void sqlite4Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){
  static const FuncDef attach_func = {
    3,                /* nArg */
    SQLITE4_UTF8,      /* iPrefEnc */
    0,                /* flags */
    0,                /* pUserData */
    0,                /* pNext */
    attachFunc,       /* xFunc */
    0,                /* xStep */
    0,                /* xFinalize */
    "sqlite_attach",  /* zName */

/* During the search for the best function definition, this procedure
** is called to test how well the function passed as the first argument
** matches the request for a function with nArg arguments in a system
** that uses encoding enc. The value returned indicates how well the
** request is matched. A higher value indicates a better match.
**
** The returned value is always between 0 and 6, as follows:
**
** 0: Not a match, or if nArg<0 and the function is has no implementation.
** 1: A variable arguments function that prefers UTF-8 when a UTF-16
**    encoding is requested, or vice versa.
** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
**    requested, or vice versa.
** 3: A variable arguments function using the same text encoding.
** 4: A function with the exact number of arguments requested that
**    prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
** 5: A function with the exact number of arguments requested that
**    prefers UTF-16LE when UTF-16BE is requested, or vice versa.
** 6: An exact match.
**
*/
static int matchQuality(FuncDef *p, int nArg, u8 enc){
  int match = 0;
  if( p->nArg==-1 || p->nArg==nArg 
   || (nArg==-1 && (p->xFunc!=0 || p->xStep!=0))
  ){
    match = 1;
    if( p->nArg==nArg || nArg==-1 ){
      match = 4;
    }
    if( enc==p->iPrefEnc ){
      match += 2;
    }
    else if( (enc==SQLITE4_UTF16LE && p->iPrefEnc==SQLITE4_UTF16BE) ||
             (enc==SQLITE4_UTF16BE && p->iPrefEnc==SQLITE4_UTF16LE) ){
      match += 1;
    }
  }
  return match;
}

/*
** Search a FuncDefTable for a function with the given name.  Return
** a pointer to the matching FuncDef if found, or 0 if there is no match.
*/
static FuncDef *functionSearch(

/*
** Locate a user function given a name, a number of arguments and a flag
** indicating whether the function prefers UTF-16 over UTF-8.  Return a
** pointer to the FuncDef structure that defines that function, or return
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.  When createFlag is true
** and the nArg parameter is -1, then only a function that accepts
** any number of arguments will be returned.
**
** If createFlag is false and nArg is -1, then the first valid
** function found is returned.  A function is valid if either xFunc
** or xStep is non-zero.
**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
FuncDef *sqlite4FindFunction(
  sqlite4 *db,       /* An open database */
  const char *zName, /* Name of the function.  Not null-terminated */
  int nName,         /* Number of characters in the name */
  int nArg,          /* Number of arguments.  -1 means any number */
  u8 enc,            /* Preferred text encoding */
  int createFlag     /* Create new entry if true and does not otherwise exist */
){
  FuncDef *p;         /* Iterator variable */
  FuncDef *pBest = 0; /* Best match found so far */
  int bestScore = 0;  /* Score of best match */


  assert( enc==SQLITE4_UTF8 || enc==SQLITE4_UTF16LE || enc==SQLITE4_UTF16BE );

  /* First search for a match amongst the application-defined functions.
  */
  p = functionSearch(&db->aFunc, zName, nName);
  while( p ){
    int score = matchQuality(p, nArg, enc);
    if( score>bestScore ){
      pBest = p;
      bestScore = score;
    }
    p = p->pSameName;
  }

  ** So we must not search for built-ins when creating a new function.
  */ 
  if( !createFlag && (pBest==0 || (db->flags & SQLITE4_PreferBuiltin)!=0) ){
    FuncDefTable *pFuncTab = &db->pEnv->aGlobalFuncs;
    bestScore = 0;
    p = functionSearch(pFuncTab, zName, nName);
    while( p ){
      int score = matchQuality(p, nArg, enc);
      if( score>bestScore ){
        pBest = p;
        bestScore = score;
      }
      p = p->pSameName;
    }
  }

  /* If the createFlag parameter is true and the search did not reveal an
  ** exact match for the name, number of arguments and encoding, then add a
  ** new entry to the hash table and return it.
  */
  if( createFlag && (bestScore<6 || pBest->nArg!=nArg) && 
      (pBest = sqlite4DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
    pBest->zName = (char *)&pBest[1];
    pBest->nArg = (u16)nArg;
    pBest->iPrefEnc = enc;
    memcpy(pBest->zName, zName, nName);
    pBest->zName[nName] = 0;
    sqlite4FuncDefInsert(&db->aFunc, pBest, 0);
  }

  if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){
    return pBest;

      ExprList *pFarg;       /* List of function arguments */
      int nFarg;             /* Number of function arguments */
      FuncDef *pDef;         /* The function definition object */
      int nId;               /* Length of the function name in bytes */
      const char *zId;       /* The function name */
      int constMask = 0;     /* Mask of function arguments that are constant */
      int i;                 /* Loop counter */
      u8 enc = ENC(db);      /* The text encoding used by this database */
      CollSeq *pColl = 0;    /* A collating sequence */

      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      testcase( op==TK_CONST_FUNC );
      testcase( op==TK_FUNCTION );
      if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;
      }else{
        pFarg = pExpr->x.pList;
      }
      nFarg = pFarg ? pFarg->nExpr : 0;
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      zId = pExpr->u.zToken;
      nId = sqlite4Strlen30(zId);
      pDef = sqlite4FindFunction(db, zId, nId, nFarg, enc, 0);
      if( pDef==0 ){
        sqlite4ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
        break;
      }

      /* Attempt a direct implementation of the built-in COALESCE() and
      ** IFNULL() functions.  This avoids unnecessary evalation of

          if( sqlite4ExprCompare(pItem->pExpr, pExpr)==0 ){
            break;
          }
        }
        if( i>=pAggInfo->nFunc ){
          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
          */
          u8 enc = ENC(pParse->db);
          i = addAggInfoFunc(pParse->db, pAggInfo);
          if( i>=0 ){
            assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
            pItem = &pAggInfo->aFunc[i];
            pItem->pExpr = pExpr;
            pItem->iMem = ++pParse->nMem;
            assert( !ExprHasProperty(pExpr, EP_IntValue) );
            pItem->pFunc = sqlite4FindFunction(pParse->db,
                   pExpr->u.zToken, sqlite4Strlen30(pExpr->u.zToken),
                   pExpr->x.pList ? pExpr->x.pList->nExpr : 0, enc, 0);
            if( pExpr->flags & EP_Distinct ){
              pItem->iDistinct = pParse->nTab++;
            }else{
              pItem->iDistinct = -1;
            }
          }
        }

/*
** Register the default FTS5 tokenizer and functions with handle db.
*/
int sqlite4InitFts5(sqlite4 *db){
#ifdef SQLITE4_TEST
  int rc = sqlite4_create_function(
      db, "fts5_parse_expr", 3, SQLITE4_UTF8, 0, fts5_parse_expr, 0, 0, 0
  );
  if( rc!=SQLITE4_OK ) return rc;
#endif
  return sqlite4InitFts5Func(db);
}

}

/*
** Set the LIKEOPT flag on the 2-argument function with the given name.
*/
static void setLikeOptFlag(sqlite4 *db, const char *zName, u8 flagVal){
  FuncDef *pDef;
  pDef = sqlite4FindFunction(db, zName, sqlite4Strlen30(zName),
                             2, SQLITE4_UTF8, 0);
  if( ALWAYS(pDef) ){
    pDef->flags = flagVal;
  }
}

/*
** Register the built-in LIKE and GLOB functions.  The caseSensitive
** parameter determines whether or not the LIKE operator is case
** sensitive.  GLOB is always case sensitive.
*/
void sqlite4RegisterLikeFunctions(sqlite4 *db, int caseSensitive){
  struct compareInfo *pInfo;
  if( caseSensitive ){
    pInfo = (struct compareInfo*)&likeInfoAlt;
  }else{
    pInfo = (struct compareInfo*)&likeInfoNorm;
  }
  sqlite4CreateFunc(db, "like", 2, SQLITE4_UTF8, pInfo, likeFunc, 0, 0, 0);
  sqlite4CreateFunc(db, "like", 3, SQLITE4_UTF8, pInfo, likeFunc, 0, 0, 0);
  sqlite4CreateFunc(db, "glob", 2, SQLITE4_UTF8, 
      (struct compareInfo*)&globInfo, likeFunc, 0, 0, 0);
  setLikeOptFlag(db, "glob", SQLITE4_FUNC_LIKE | SQLITE4_FUNC_CASE);
  setLikeOptFlag(db, "like", 
      caseSensitive ? (SQLITE4_FUNC_LIKE | SQLITE4_FUNC_CASE) : SQLITE4_FUNC_LIKE);
}

/*

   || !pExpr->x.pList 
   || pExpr->x.pList->nExpr!=2
  ){
    return 0;
  }
  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
  pDef = sqlite4FindFunction(db, pExpr->u.zToken, 
                             sqlite4Strlen30(pExpr->u.zToken),
                             2, SQLITE4_UTF8, 0);
  if( NEVER(pDef==0) || (pDef->flags & SQLITE4_FUNC_LIKE)==0 ){
    return 0;
  }

  /* The memcpy() statement assumes that the wildcard characters are
  ** the first three statements in the compareInfo structure.  The
  ** asserts() that follow verify that assumption

    FUNCTION(round,              1, 0, 0, roundFunc        ),
    FUNCTION(round,              2, 0, 0, roundFunc        ),
    FUNCTION(upper,              1, 0, 0, upperFunc        ),
    FUNCTION(lower,              1, 0, 0, lowerFunc        ),
    FUNCTION(coalesce,           1, 0, 0, 0                ),
    FUNCTION(coalesce,           0, 0, 0, 0                ),
/*  FUNCTION(coalesce,          -1, 0, 0, ifnullFunc       ), */
    {-1,SQLITE4_UTF8,SQLITE4_FUNC_COALESCE,0,0,ifnullFunc,0,0,"coalesce",0,0},
    FUNCTION(hex,                1, 0, 0, hexFunc          ),
/*  FUNCTION(ifnull,             2, 0, 0, ifnullFunc       ), */
    {2,SQLITE4_UTF8,SQLITE4_FUNC_COALESCE,0,0,ifnullFunc,0,0,"ifnull",0,0},
    FUNCTION(random,             0, 0, 0, randomFunc       ),
    FUNCTION(randomblob,         1, 0, 0, randomBlob       ),
    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
    FUNCTION(sqlite_version,     0, 0, 0, versionFunc      ),
    FUNCTION(sqlite_source_id,   0, 0, 0, sourceidFunc     ),
    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
#ifndef SQLITE4_OMIT_COMPILEOPTION_DIAGS

    FUNCTION(load_extension,     1, 0, 0, loadExt          ),
    FUNCTION(load_extension,     2, 0, 0, loadExt          ),
  #endif
    AGGREGATE(sum,               1, 0, 0, sumStep,         sumFinalize    ),
    AGGREGATE(total,             1, 0, 0, sumStep,         totalFinalize    ),
    AGGREGATE(avg,               1, 0, 0, sumStep,         avgFinalize    ),
 /* AGGREGATE(count,             0, 0, 0, countStep,       countFinalize  ), */
    {0,SQLITE4_UTF8,SQLITE4_FUNC_COUNT,0,0,0,countStep,countFinalize,"count",0,0},
    AGGREGATE(count,             1, 0, 0, countStep,       countFinalize  ),
    AGGREGATE(group_concat,      1, 0, 0, groupConcatStep, groupConcatFinalize),
    AGGREGATE(group_concat,      2, 0, 0, groupConcatStep, groupConcatFinalize),
  
    LIKEFUNC(glob, 2, &globInfo, SQLITE4_FUNC_LIKE|SQLITE4_FUNC_CASE),
  #ifdef SQLITE4_CASE_SENSITIVE_LIKE
    LIKEFUNC(like, 2, &likeInfoAlt, SQLITE4_FUNC_LIKE|SQLITE4_FUNC_CASE),

** that if a malloc() fails in sqlite4_create_function(), an error code
** is returned and the mallocFailed flag cleared. 
*/
int sqlite4CreateFunc(
  sqlite4 *db,
  const char *zFunctionName,
  int nArg,
  int enc,
  void *pUserData,
  void (*xFunc)(sqlite4_context*,int,sqlite4_value **),
  void (*xStep)(sqlite4_context*,int,sqlite4_value **),
  void (*xFinal)(sqlite4_context*),
  FuncDestructor *pDestructor
){
  FuncDef *p;
  int nName;

  assert( sqlite4_mutex_held(db->mutex) );
  if( zFunctionName==0 ||
      (xFunc && (xFinal || xStep)) || 
      (!xFunc && (xFinal && !xStep)) ||
      (!xFunc && (!xFinal && xStep)) ||
      (nArg<-1 || nArg>SQLITE4_MAX_FUNCTION_ARG) ||
      (255<(nName = sqlite4Strlen30( zFunctionName))) ){
    return SQLITE4_MISUSE_BKPT;
  }
  
#ifndef SQLITE4_OMIT_UTF16
  /* If SQLITE4_UTF16 is specified as the encoding type, transform this
  ** to one of SQLITE4_UTF16LE or SQLITE4_UTF16BE using the
  ** SQLITE4_UTF16NATIVE macro. SQLITE4_UTF16 is not used internally.
  **
  ** If SQLITE4_ANY is specified, add three versions of the function
  ** to the hash table.
  */
  if( enc==SQLITE4_UTF16 ){
    enc = SQLITE4_UTF16NATIVE;
  }else if( enc==SQLITE4_ANY ){
    int rc;
    rc = sqlite4CreateFunc(db, zFunctionName, nArg, SQLITE4_UTF8,
         pUserData, xFunc, xStep, xFinal, pDestructor);
    if( rc==SQLITE4_OK ){
      rc = sqlite4CreateFunc(db, zFunctionName, nArg, SQLITE4_UTF16LE,
          pUserData, xFunc, xStep, xFinal, pDestructor);
    }
    if( rc!=SQLITE4_OK ){
      return rc;
    }
    enc = SQLITE4_UTF16BE;
  }
#else
  enc = SQLITE4_UTF8;
#endif
  
  /* Check if an existing function is being overridden or deleted. If so,
  ** and there are active VMs, then return SQLITE4_BUSY. If a function
  ** is being overridden/deleted but there are no active VMs, allow the
  ** operation to continue but invalidate all precompiled statements.
  */
  p = sqlite4FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
  if( p && p->iPrefEnc==enc && p->nArg==nArg ){
    if( db->activeVdbeCnt ){
      sqlite4Error(db, SQLITE4_BUSY, 
        "unable to delete/modify user-function due to active statements");
      assert( !db->mallocFailed );
      return SQLITE4_BUSY;
    }else{
      sqlite4ExpirePreparedStatements(db);
    }
  }

  p = sqlite4FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
  assert(p || db->mallocFailed);
  if( !p ){
    return SQLITE4_NOMEM;
  }

  /* If an older version of the function with a configured destructor is
  ** being replaced invoke the destructor function here. */

** This function is the same as sqlite4_create_function(), except that
** it does not grab the database handle mutex or call sqlite4ApiExit().
*/
static int createFunctionDestructor(
  sqlite4 *db,
  const char *zFunc,
  int nArg,
  int enc,
  void *p,
  void (*xFunc)(sqlite4_context*,int,sqlite4_value **),
  void (*xStep)(sqlite4_context*,int,sqlite4_value **),
  void (*xFinal)(sqlite4_context*),
  void (*xDestroy)(void *)
){
  int rc;
  FuncDestructor *pArg = 0;

  if( xDestroy ){
    pArg = (FuncDestructor *)sqlite4DbMallocZero(db, sizeof(FuncDestructor));
    if( !pArg ){
      xDestroy(p);
      return SQLITE4_NOMEM;
    }
    pArg->xDestroy = xDestroy;
    pArg->pUserData = p;
  }
  rc = sqlite4CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
  if( pArg && pArg->nRef==0 ){
    assert( rc!=SQLITE4_OK );
    xDestroy(p);
    sqlite4DbFree(db, pArg);
  }

  return rc;
}

/*
** Create new user functions.
*/
int sqlite4_create_function(
  sqlite4 *db,
  const char *zFunc,
  int nArg,
  int enc,
  void *p,
  void (*xFunc)(sqlite4_context*,int,sqlite4_value **),
  void (*xStep)(sqlite4_context*,int,sqlite4_value **),
  void (*xFinal)(sqlite4_context*),
  void (*xDestroy)(void *)
){
  int rc;
  sqlite4_mutex_enter(db->mutex);
  rc = createFunctionDestructor(
      db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, xDestroy
  );
  rc = sqlite4ApiExit(db, rc);
  sqlite4_mutex_leave(db->mutex);
  return rc;
}

int sqlite4_create_mi_function(
  sqlite4 *db,
  const char *zFunc,
  int nArg,
  int enc,
  void *p,
  void (*xFunc)(sqlite4_context*,int,sqlite4_value **),
  void (*xDestroy)(void *)
){
  int rc;
  int n;

  n = nArg + (nArg>=0);
  sqlite4_mutex_enter(db->mutex);
  rc = sqlite4_create_function(db, zFunc, n, enc, p, xFunc, 0,0, xDestroy);
  if( rc==SQLITE4_OK ){
    FuncDef *p = sqlite4FindFunction(db, zFunc, -1, n, enc, 0);
    p->bMatchinfo = 1;
  }
  rc = sqlite4ApiExit(db, rc);
  sqlite4_mutex_leave(db->mutex);
  return rc;
}

  sqlite4 *db,
  const char *zName,
  int nArg
){
  int nName = sqlite4Strlen30(zName);
  int rc = SQLITE4_OK;
  sqlite4_mutex_enter(db->mutex);
  if( sqlite4FindFunction(db, zName, nName, nArg, SQLITE4_UTF8, 0)==0 ){
    rc = sqlite4CreateFunc(db, zName, nArg, SQLITE4_UTF8,
                           0, sqlite4InvalidFunction, 0, 0, 0);
  }
  rc = sqlite4ApiExit(db, rc);
  sqlite4_mutex_leave(db->mutex);
  return rc;
}

            zErr = sqlite4MPrintf(
                db, "entry missing from index %s: ", pIdx->zName
            );
            sqlite4VdbeAddOp4(v, OP_String8, 0, regTmp, 0, zErr, 0);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeAddOp3(v, OP_Function, 0, regKey, regTmp);
            sqlite4VdbeChangeP4(v, -1,
                (char *)sqlite4FindFunction(db, "hex", 3, 1, SQLITE4_UTF8, 0), 
                P4_FUNCDEF
            );
            sqlite4VdbeChangeP5(v, 1);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeAddOp4(v, OP_String8, 0, regTmp, 0, "\n", 0);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeJumpHere(v, jmp);

            zErr = sqlite4MPrintf(
                db, "entry missing from index %s: ", pIdx->zName
            );
            sqlite4VdbeAddOp4(v, OP_String8, 0, regTmp, 0, zErr, 0);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeAddOp3(v, OP_Function, 0, regKey, regTmp);
            sqlite4VdbeChangeP4(v, -1,
                (char *)sqlite4FindFunction(db, "hex", 3, 1, SQLITE4_UTF8, 0), 
                P4_FUNCDEF
            );
            sqlite4VdbeChangeP5(v, 1);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeAddOp4(v, OP_String8, 0, regTmp, 0, "\n", 0);
            sqlite4VdbeAddOp3(v, OP_Concat, regTmp, regErrstr, regErrstr);
            sqlite4VdbeJumpHere(v, jmp);

      FuncDef *pDef;              /* Information about the function */
      u8 enc = ENC(pParse->db);   /* The database encoding */

      testcase( pExpr->op==TK_CONST_FUNC );
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      zId = pExpr->u.zToken;
      nId = sqlite4Strlen30(zId);
      pDef = sqlite4FindFunction(pParse->db, zId, nId, n, enc, 0);
      if( pDef==0 ){
        pDef = sqlite4FindFunction(pParse->db, zId, nId, -1, enc, 0);
        if( pDef==0 ){
          no_such_func = 1;
        }else{
          wrong_num_args = 1;
        }
      }else{
        is_agg = pDef->xFunc==0;

** the database fails to open, print an error message and exit.
*/
static void open_db(struct callback_data *p){
  if( p->db==0 ){
    sqlite4_open(0, p->zDbFilename, &p->db, 0);
    db = p->db;
    if( db && sqlite4_errcode(db)==SQLITE4_OK ){
      sqlite4_create_function(db, "shellstatic", 0, SQLITE4_UTF8, 0,
          shellstaticFunc, 0, 0, 0);
    }
    if( db==0 || SQLITE4_OK!=sqlite4_errcode(db) ){
      fprintf(stderr,"Error: unable to open database \"%s\": %s\n", 
          p->zDbFilename, sqlite4_errmsg(db));
      exit(1);
    }

** ^The third parameter (nArg) is the number of arguments that the SQL 
** function or aggregate takes. ^If this parameter is -1, then the SQL 
** function or aggregate may take any number of arguments between 0 and 
** the limit set by [sqlite4_limit]([SQLITE4_LIMIT_FUNCTION_ARG]).  If 
** the third parameter is less than -1 or greater than 127 then the 
** behavior is undefined.
**
** ^The fourth parameter, eTextRep, specifies the
** [SQLITE4_UTF8 | text encoding] this SQL function prefers for
** its parameters.  Every SQL function implementation must be able to work
** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
** more efficient with one encoding than another.  ^An application may
** invoke sqlite4_create_function() multiple times with the same function 
** but with different values of eTextRep. ^When multiple implementations 
** of the same function are available, SQLite will pick the one that 
** involves the least amount of data conversion. If there is only a single 
** implementation which does not care what text encoding is used, then the 
** fourth argument should be [SQLITE4_ANY].
**
** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
** function can gain access to this pointer using [sqlite4_context_appdata()].)^
**
** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
** pointers to C-language functions that implement the SQL function or
** aggregate. ^A scalar SQL function requires an implementation of the xFunc
** callback only; NULL pointers must be passed as the xStep and xFinal
** parameters. ^An aggregate SQL function requires an implementation of xStep
** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
** SQL function or aggregate, pass NULL pointers for all three function
** callbacks.
**
** ^(If the ninth parameter is not NULL, then it is destructor for the 
** application data pointer. The destructor is invoked when the function 
** is deleted, either by being overloaded or when the database connection 
** closes.)^ ^The destructor is also invoked if the call to
** sqlite4_create_function() fails. ^When the destructor callback 
** is invoked, it is passed a single argument which is a copy of the 
** application data pointer which was the fifth parameter to 
** sqlite4_create_function().
**
** ^It is permitted to register multiple implementations of the same
** functions with the same name but with either differing numbers of
** arguments or differing preferred text encodings.  ^SQLite will use
** the implementation that most closely matches the way in which the
** SQL function is used.  ^A function implementation with a non-negative
** nArg parameter is a better match than a function implementation with
** a negative nArg.  ^A function where the preferred text encoding
** matches the database encoding is a better
** match than a function where the encoding is different.  
** ^A function where the encoding difference is between UTF16le and UTF16be
** is a closer match than a function where the encoding difference is
** between UTF8 and UTF16.
**
** ^Built-in functions may be overloaded by new application-defined functions.
**
** ^An application-defined function is permitted to call other
** SQLite interfaces.  However, such calls must not
** close the database connection nor finalize or reset the prepared
** statement in which the function is running.
*/
int sqlite4_create_function(
  sqlite4 *db,
  const char *zFunctionName,
  int nArg,
  int eTextRep,
  void *pApp,
  void (*xFunc)(sqlite4_context*,int,sqlite4_value**),
  void (*xStep)(sqlite4_context*,int,sqlite4_value**),
  void (*xFinal)(sqlite4_context*),
  void(*xDestroy)(void*)
);

** Each SQL function is defined by an instance of the following
** structure.  A pointer to this structure is stored in the sqlite.aFunc
** hash table.  When multiple functions have the same name, the hash table
** points to a linked list of these structures.
*/
struct FuncDef {
  i16 nArg;            /* Number of arguments.  -1 means unlimited */
  u8 iPrefEnc;         /* Preferred text encoding (SQLITE4_UTF8, 16LE, 16BE) */
  u8 flags;            /* Some combination of SQLITE4_FUNC_* */
  void *pUserData;     /* User data parameter */
  FuncDef *pSameName;  /* Next with a different name but the same hash */
  void (*xFunc)(sqlite4_context*,int,sqlite4_value**); /* Regular function */
  void (*xStep)(sqlite4_context*,int,sqlite4_value**); /* Aggregate step */
  void (*xFinalize)(sqlite4_context*);                /* Aggregate finalizer */
  char *zName;         /* SQL name of the function. */

**     that accepts nArg arguments and is implemented by a call to C 
**     function likeFunc. Argument pArg is cast to a (void *) and made
**     available as the function user-data (sqlite4_context_appdata()). The
**     FuncDef.flags variable is set to the value passed as the flags
**     parameter.
*/
#define FUNCTION(zName, nArg, iArg, bNC, xFunc) \
  {nArg, SQLITE4_UTF8, bNC*SQLITE4_FUNC_NEEDCOLL, \
   SQLITE4_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
#define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
  {nArg, SQLITE4_UTF8, bNC*SQLITE4_FUNC_NEEDCOLL, \
   pArg, 0, xFunc, 0, 0, #zName, 0, 0}
#define LIKEFUNC(zName, nArg, arg, flags) \
  {nArg, SQLITE4_UTF8, flags, (void *)arg, 0, likeFunc, 0, 0, #zName, 0, 0}
#define AGGREGATE(zName, nArg, arg, nc, xStep, xFinal) \
  {nArg, SQLITE4_UTF8, nc*SQLITE4_FUNC_NEEDCOLL, \
   SQLITE4_INT_TO_PTR(arg), 0, 0, xStep,xFinal,#zName,0,0}

/*
** All current savepoints are stored in a linked list starting at
** sqlite4.pSavepoint. The first element in the list is the most recently
** opened savepoint. Savepoints are added to the list by the vdbe
** OP_Savepoint instruction.

void sqlite4HaltConstraint(Parse*, int, char*, int);
Expr *sqlite4ExprDup(sqlite4*,Expr*,int);
ExprList *sqlite4ExprListDup(sqlite4*,ExprList*,int);
SrcList *sqlite4SrcListDup(sqlite4*,SrcList*,int);
IdList *sqlite4IdListDup(sqlite4*,IdList*);
Select *sqlite4SelectDup(sqlite4*,Select*,int);
void sqlite4FuncDefInsert(FuncDefTable*, FuncDef*, int);
FuncDef *sqlite4FindFunction(sqlite4*,const char*,int,int,u8,int);
void sqlite4RegisterBuiltinFunctions(sqlite4*);
void sqlite4RegisterDateTimeFunctions(sqlite4_env*);
void sqlite4RegisterGlobalFunctions(sqlite4_env*);
int sqlite4SafetyCheckOk(sqlite4*);
int sqlite4SafetyCheckSickOrOk(sqlite4*);
void sqlite4ChangeCookie(Parse*, int);

void sqlite4DefaultRowEst(Index*);
void sqlite4RegisterLikeFunctions(sqlite4*, int);
int sqlite4IsLikeFunction(sqlite4*,Expr*,int*,char*);
void sqlite4SchemaClear(sqlite4_env*,Schema*);
Schema *sqlite4SchemaGet(sqlite4*);
int sqlite4SchemaToIndex(sqlite4 *db, Schema *);
KeyInfo *sqlite4IndexKeyinfo(Parse *, Index *);
int sqlite4CreateFunc(sqlite4 *, const char *, int, int, void *, 
  void (*)(sqlite4_context*,int,sqlite4_value **),
  void (*)(sqlite4_context*,int,sqlite4_value **), void (*)(sqlite4_context*),
  FuncDestructor *pDestructor
);
int sqlite4ApiExit(sqlite4 *db, int);
int sqlite4OpenTempDatabase(Parse *);

    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 = sqlite4_create_function(pDb->db, zName, nArg, SQLITE4_UTF8,
        pFunc, tclSqlFunc, 0, 0, 0);
    if( rc!=SQLITE4_OK ){
      rc = TCL_ERROR;
      Tcl_SetResult(interp, (char *)sqlite4_errmsg(pDb->db), TCL_VOLATILE);
    }
    break;
  }

  char zBuf[33];
  p = sqlite4_aggregate_context(context, sizeof(*p));
  MD5Final(digest,p);
  MD5DigestToBase16(digest, zBuf);
  sqlite4_result_text(context, zBuf, -1, SQLITE4_TRANSIENT, 0);
}
int Md5_Register(sqlite4 *db){
  int rc = sqlite4_create_function(db, "md5sum", -1, SQLITE4_UTF8, 0, 0, 
                                 md5step, md5finalize, 0);
  sqlite4_overload_function(db, "md5sum", -1);  /* To exercise this API */
  return rc;
}
#endif /* defined(SQLITE4_TEST) */

# with functions created using sqlite4_create_function_v2() is 
# correctly invoked.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl


ifcapable utf16 {
  do_test func3-1.1 {
    set destroyed 0
    proc destroy {} { set ::destroyed 1 }
    sqlite4_create_function_v2 db f2 -1 any -func f2 -destroy destroy
    set destroyed
  } 0
  do_test func3-1.2 {
    sqlite4_create_function_v2 db f2 -1 utf8 -func f2
    set destroyed
  } 0
  do_test func3-1.3 {
    sqlite4_create_function_v2 db f2 -1 utf16le -func f2
    set destroyed
  } 0
  do_test func3-1.4 {
    sqlite4_create_function_v2 db f2 -1 utf16be -func f2
    set destroyed
  } 1
}

do_test func3-2.1 {
  set destroyed 0
  proc destroy {} { set ::destroyed 1 }
  sqlite4_create_function_v2 db f3 -1 utf8 -func f3 -destroy destroy
  set destroyed
} 0
do_test func3-2.2 {

  printf.test 
  quote.test

  savepoint.test savepoint5.test 

  select1.test select2.test select3.test select4.test select5.test 
  select6.test select7.test select8.test select9.test selectA.test 
  selectB.test selectC.test 

  sort.test
  storage1.test

  subquery.test subquery2.test
  substr.test 

4 0 "SELECT (a/2) FROM t1 GROUP BY (a/2)" {0 1 2 3}
5 0 "SELECT a+b FROM t1 GROUP BY (a+b)" {12 15 18 3 6 9}
6 1 "SELECT a+b FROM t1 GROUP BY (a+b) ORDER BY 1" {3 6 9 12 15 18}
7 0 "SELECT a*b FROM t1 WHERE (c%2)" {18 2 50}
8 0 "SELECT count(*) FROM t1, t1 AS t2 WHERE t1.a=t2.a" {6}
9 0 "SELECT * FROM t1 WHERE a=1 AND b=2" {{1 2 3}}
10 0 "SELECT * FROM t1 WHERE a>3 AND b<12" {{4 8 12} {5 10 15}}





}

finish_test

    { "test_isolation",        2, SQLITE4_UTF8, test_isolation},
    { "test_counter",          1, SQLITE4_UTF8, counterFunc},
  };
  int i;

  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
    sqlite4_create_function(db, aFuncs[i].zName, aFuncs[i].nArg,
        aFuncs[i].eTextRep, 0, aFuncs[i].xFunc, 0, 0, 0);
  }

  return SQLITE4_OK;
}

/*
** A bogus step function and finalizer function.

  sqlite4 *db;
  int rc;
  int mxArg;

  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

  rc = sqlite4_create_function(
      db, "tx", 1, SQLITE4_UTF8, 0, tStep, tStep, tFinal, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", 1, SQLITE4_UTF8, 0, tStep, tStep, 0,0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", 1, SQLITE4_UTF8, 0, tStep, 0,tFinal,0);
  if( rc!=SQLITE4_MISUSE) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", 1, SQLITE4_UTF8, 0, 0, 0, tFinal, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", 1, SQLITE4_UTF8, 0, 0, tStep, 0, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", -2, SQLITE4_UTF8, 0, tStep, 0, 0, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "tx", 128, SQLITE4_UTF8, 0, tStep, 0, 0, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  rc = sqlite4_create_function(db, "funcxx"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789",
       1, SQLITE4_UTF8, 0, tStep, 0, 0, 0);
  if( rc!=SQLITE4_MISUSE ) goto abuse_err;

  /* This last function registration should actually work.  Generate
  ** a no-op function (that always returns NULL) and which has the
  ** maximum-length function name and the maximum number of parameters.
  */
  sqlite4_limit(db, SQLITE4_LIMIT_FUNCTION_ARG, 10000);
  mxArg = sqlite4_limit(db, SQLITE4_LIMIT_FUNCTION_ARG, -1);
  rc = sqlite4_create_function(db, "nullx"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789"
       "_123456789_123456789_123456789_123456789_123456789",
       mxArg, SQLITE4_UTF8, 0, tStep, 0, 0, 0);
  if( rc!=SQLITE4_OK ) goto abuse_err;
                                
  return TCL_OK;

abuse_err:
  Tcl_AppendResult(interp, "sqlite4_create_function abused test failed", 
                   (char*)0);

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " DB\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite4_create_function(db, "x_coalesce", -1, SQLITE4_ANY, 0, 
        t1_ifnullFunc, 0, 0, 0);
  if( rc==SQLITE4_OK ){
    rc = sqlite4_create_function(db, "hex8", 1, SQLITE4_ANY, 0, 
          hex8Func, 0, 0, 0);
  }
#ifndef SQLITE4_OMIT_UTF16
  if( rc==SQLITE4_OK ){
    rc = sqlite4_create_function(db, "hex16", 1, SQLITE4_ANY, 0, 
          hex16Func, 0, 0, 0);
  }
#endif
  if( rc==SQLITE4_OK ){
    rc = sqlite4_create_function(db, "tkt2213func", 1, SQLITE4_ANY, 0, 
          tkt2213Function, 0, 0, 0);
  }

  if( rc==SQLITE4_OK ){
    rc = sqlite4_create_function(
        db, "x_sqlite_exec", 1, SQLITE4_UTF16, db, sqlite4ExecFunc, 0, 0, 0
    );
  }

  if( sqlite4TestErrCode(interp, db, rc) ) return TCL_ERROR;
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), 0);
  return TCL_OK;
}

  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite4_create_function(db, "x_count", 0, SQLITE4_UTF8, 0, 0,
      t1CountStep, t1CountFinalize, 0);
  if( rc==SQLITE4_OK ){
    rc = sqlite4_create_function(db, "x_count", 1, SQLITE4_UTF8, 0, 0,
        t1CountStep, t1CountFinalize, 0);
  }
  if( sqlite4TestErrCode(interp, db, rc) ) return TCL_ERROR;
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), 0);
  return TCL_OK;
}

  if( p->pDestroy ) p->pDestroy = Tcl_DuplicateObj(p->pDestroy); 

  if( p->pFunc ) Tcl_IncrRefCount(p->pFunc); 
  if( p->pStep ) Tcl_IncrRefCount(p->pStep); 
  if( p->pFinal ) Tcl_IncrRefCount(p->pFinal); 
  if( p->pDestroy ) Tcl_IncrRefCount(p->pDestroy); 

  rc = sqlite4_create_function(db, zFunc, nArg, enc, (void *)p, 
      (p->pFunc ? cf2Func : 0),
      (p->pStep ? cf2Step : 0),
      (p->pFinal ? cf2Final : 0),
      cf2Destroy
  );
  if( rc!=SQLITE4_OK ){
    Tcl_ResetResult(interp);

  int rc;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
       " DB FUNCTION-NAME", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite4_create_function(db, argv[2], -1, SQLITE4_UTF8, 0, 
      testFunc, 0, 0, 0);
  if( rc!=0 ){
    Tcl_AppendResult(interp, sqlite4ErrStr(rc), 0);
    return TCL_ERROR;
  }
  if( sqlite4TestErrCode(interp, db, rc) ) return TCL_ERROR;
  return TCL_OK;
}

  int val;

  if( objc!=5 ) goto bad_args;
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

  if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[2], &val) ) return TCL_ERROR;
  if( val ){
    sqlite4_create_function(db, "test_function", 1, SQLITE4_UTF8, 
        interp, test_function_utf8, 0, 0, 0);
  }
  if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[3], &val) ) return TCL_ERROR;
  if( val ){
    sqlite4_create_function(db, "test_function", 1, SQLITE4_UTF16LE, 
        interp, test_function_utf16le, 0, 0, 0);
  }
  if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[4], &val) ) return TCL_ERROR;
  if( val ){
    sqlite4_create_function(db, "test_function", 1, SQLITE4_UTF16BE, 
        interp, test_function_utf16be, 0, 0, 0);
  }

  return TCL_OK;
bad_args:
  Tcl_AppendResult(interp, "wrong # args: should be \"",
      Tcl_GetStringFromObj(objv[0], 0), " <DB> <utf8> <utf16le> <utf16be>", 0);

  sqlite4 *db;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
        " DB function-name", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite4_create_function(db, argv[2], -1, SQLITE4_UTF8, 0, 0, 0, 0, 0);
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
  return TCL_OK;
}

/*
** Usage: sqlite_delete_collation DB collation-name
**