SQLite

  /* 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<FUNC_PERFECT_MATCH && 
      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
    FuncDef *pOther;
    u8 *z;
    pBest->zName = (const char*)&pBest[1];
    pBest->nArg = (u16)nArg;
    pBest->funcFlags = enc;
    memcpy((char*)&pBest[1], zName, nName+1);
    for(z=(u8*)pBest->zName; *z; z++) *z = sqlite3UpperToLower[*z];
    pOther = (FuncDef*)sqlite3HashInsert(&db->aFunc, pBest->zName, pBest);
    if( pOther==pBest ){
      sqlite3DbFree(db, pBest);
      sqlite3OomFault(db);
      return 0;
    }else{
      pBest->pNext = pOther;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( xDestroy ){
    pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
    if( !pArg ){
      sqlite3OomFault(db);
      xDestroy(p);
      goto out;
    }
    pArg->nRef = 0;
    pArg->xDestroy = xDestroy;
    pArg->pUserData = p;
  }
  rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
  if( pArg && pArg->nRef==0 ){
    assert( rc!=SQLITE_OK );
    xDestroy(p);
    sqlite3_free(pArg);
  }

 out:
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

  sqlite3DbFree(db, zFunc8);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}
#endif


/*
** The following is the implementation of an SQL function that always
** fails with an error message stating that the function is used in the
** wrong context.  The sqlite3_overload_function() API might construct
** SQL function that use this routine so that the functions will exist
** for name resolution but are actually overloaded by the xFindFunction
** method of virtual tables.
*/
static void sqlite3InvalidFunction(
  sqlite3_context *context,  /* The function calling context */
  int NotUsed,               /* Number of arguments to the function */
  sqlite3_value **NotUsed2   /* Value of each argument */
){
  const char *zName = (const char*)sqlite3_user_data(context);
  char *zErr;
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  zErr = sqlite3_mprintf(
      "unable to use function %s in the requested context", zName);
  sqlite3_result_error(context, zErr, -1);
  sqlite3_free(zErr);
}

/*
** Declare that a function has been overloaded by a virtual table.
**
** If the function already exists as a regular global function, then
** this routine is a no-op.  If the function does not exist, then create
** a new one that always throws a run-time error.  
**
** When virtual tables intend to provide an overloaded function, they
** should call this routine to make sure the global function exists.
** A global function must exist in order for name resolution to work
** properly.
*/
int sqlite3_overload_function(
  sqlite3 *db,
  const char *zName,
  int nArg
){
  int rc;
  char *zCopy;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;




  sqlite3_mutex_leave(db->mutex);
  if( rc ) return SQLITE_OK;
  zCopy = sqlite3_mprintf(zName);
  if( zCopy==0 ) return SQLITE_NOMEM;
  return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
                           zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
}

#ifndef SQLITE_OMIT_TRACE
/*
** Register a trace function.  The pArg from the previously registered trace
** is returned.  
**

int sqlite3KeyInfoIsWriteable(KeyInfo*);
#endif
int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *,
  void (*)(sqlite3_context*,int,sqlite3_value **),
  void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*),
  FuncDestructor *pDestructor
);
void sqlite3NoopDestructor(void*);
void sqlite3OomFault(sqlite3*);
void sqlite3OomClear(sqlite3*);
int sqlite3ApiExit(sqlite3 *db, int);
int sqlite3OpenTempDatabase(Parse *);

void sqlite3StrAccumInit(StrAccum*, sqlite3*, char*, int, int);
char *sqlite3StrAccumFinish(StrAccum*);

void sqlite3VtabArgInit(Parse*);
void sqlite3VtabArgExtend(Parse*, Token*);
int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
int sqlite3VtabCallConnect(Parse*, Table*);
int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
int sqlite3VtabBegin(sqlite3 *, VTable *);
FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);

sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
void sqlite3ParserReset(Parse*);
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);

  if( *piTime==0 ){
    rc = sqlite3OsCurrentTimeInt64(p->pOut->db->pVfs, piTime);
    if( rc ) *piTime = 0;
  }
  return *piTime;
}























/*
** Create a new aggregate context for p and return a pointer to
** its pMem->z element.
*/
static SQLITE_NOINLINE void *createAggContext(sqlite3_context *p, int nByte){
  Mem *pMem = p->pMem;
  assert( (pMem->flags & MEM_Agg)==0 );

  }else{
    pMem->u.i = val;
    pMem->flags = MEM_Int;
  }
}

/* A no-op destructor */
void sqlite3NoopDestructor(void *p){ UNUSED_PARAMETER(p); }

/*
** Set the value stored in *pMem should already be a NULL.
** Also store a pointer to go with it.
*/
void sqlite3VdbeMemSetPointer(
  Mem *pMem,

  Table *pTab;
  sqlite3_vtab *pVtab;
  sqlite3_module *pMod;
  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**) = 0;
  void *pArg = 0;
  FuncDef *pNew;
  int rc = 0;




  /* Check to see the left operand is a column in a virtual table */
  if( NEVER(pExpr==0) ) return pDef;
  if( pExpr->op!=TK_COLUMN ) return pDef;
  pTab = pExpr->pTab;
  if( pTab==0 ) return pDef;
  if( !IsVirtual(pTab) ) return pDef;
  pVtab = sqlite3GetVTable(db, pTab)->pVtab;
  assert( pVtab!=0 );
  assert( pVtab->pModule!=0 );
  pMod = (sqlite3_module *)pVtab->pModule;
  if( pMod->xFindFunction==0 ) return pDef;
 
  /* Call the xFindFunction method on the virtual table implementation
  ** to see if the implementation wants to overload this function.
  **
  ** Though undocumented, we have historically always invoked xFindFunction
  ** with an all lower-case function name.  Continue in this tradition to
  ** avoid any chance of an incompatibility.
  */
#ifdef SQLITE_DEBUG
  {
    int i;
    for(i=0; pDef->zName[i]; i++){

      unsigned char x = (unsigned char)pDef->zName[i];
      assert( x==sqlite3UpperToLower[x] );
    }


  }
#endif
  rc = pMod->xFindFunction(pVtab, nArg, pDef->zName, &xSFunc, &pArg);
  if( rc==0 ){
    return pDef;
  }

  /* Create a new ephemeral function definition for the overloaded
  ** function */
  pNew = sqlite3DbMallocZero(db, sizeof(*pNew)