/*
** The first parameter (pDef) is a function implementation. The
** second parameter (pExpr) is the first argument to this function.
** If pExpr is a column in a virtual table, then let the virtual
** table implementation have an opportunity to overload the function.
**
** This routine is used to allow virtual table implementations to
** overload MATCH, LIKE, GLOB, and REGEXP operators.
**
** Return either the pDef argument (indicating no change) or a
** new FuncDef structure that is marked as ephemeral using the
** SQLITE_FUNC_EPHEM flag.
*/
static FuncDef sqlite3VtabOverloadFunction(
sqlite3 db, /* Database connection for reporting malloc problems */
FuncDef pDef, /* Function to possibly overload */
int nArg, /* Number of arguments to the function */
Expr pExpr /* First argument to the function */
)
{
Table pTab;
sqlite3_vtab pVtab;
sqlite3_module pMod;
dxFunc xFunc = null;//void (*xFunc)(sqlite3_context*,int,sqlite3_value*) = 0;
object pArg = null;
FuncDef pNew;
int rc = 0;
string zLowerName;
string z;
/* Check to see the left operand is a column in a virtual table */
if (NEVER(pExpr == null))
{
return(pDef);
}
if (pExpr.op != TK_COLUMN)
{
return(pDef);
}
pTab = pExpr.pTab;
if (NEVER(pTab == null))
{
return(pDef);
}
if ((pTab.tabFlags & TF_Virtual) == 0)
{
return(pDef);
}
pVtab = sqlite3GetVTable(db, pTab).pVtab;
Debug.Assert(pVtab != null);
Debug.Assert(pVtab.pModule != null);
pMod = (sqlite3_module)pVtab.pModule;
if (pMod.xFindFunction == null)
{
return(pDef);
}
/* Call the xFindFunction method on the virtual table implementation
** to see if the implementation wants to overload this function
*/
zLowerName = pDef.zName;//sqlite3DbStrDup(db, pDef.zName);
if (zLowerName != null)
{
//for(z=(unsigned char)zLowerName; *z; z++){
// *z = sqlite3UpperToLower[*z];
//}
rc = pMod.xFindFunction(pVtab, nArg, zLowerName.ToLowerInvariant(), ref xFunc, ref pArg);
sqlite3DbFree(db, ref zLowerName);
}
if (rc == 0)
{
return(pDef);
}
/* Create a new ephemeral function definition for the overloaded
** function */
//sqlite3DbMallocZero(db, sizeof(*pNew)
// + sqlite3Strlen30(pDef.zName) + 1);
//if ( pNew == null )
//{
// return pDef;
//}
pNew = pDef.Copy();
pNew.zName = pDef.zName;
//pNew.zName = (char )&pNew[1];
//memcpy(pNew.zName, pDef.zName, sqlite3Strlen30(pDef.zName)+1);
pNew.xFunc = xFunc;
pNew.pUserData = pArg;
pNew.flags |= SQLITE_FUNC_EPHEM;
return(pNew);
}
/*
** The first parameter (pDef) is a function implementation. The
** second parameter (pExpr) is the first argument to this function.
** If pExpr is a column in a virtual table, then let the virtual
** table implementation have an opportunity to overload the function.
**
** This routine is used to allow virtual table implementations to
** overload MATCH, LIKE, GLOB, and REGEXP operators.
**
** Return either the pDef argument (indicating no change) or a
** new FuncDef structure that is marked as ephemeral using the
** SQLITE_FUNC_EPHEM flag.
*/
static FuncDef sqlite3VtabOverloadFunction(
sqlite3 db, /* Database connection for reporting malloc problems */
FuncDef pDef, /* Function to possibly overload */
int nArg, /* Number of arguments to the function */
Expr pExpr /* First argument to the function */
)
{
Table pTab;
sqlite3_vtab pVtab;
sqlite3_module pMod;
dxFunc xFunc = null;//void (*xFunc)(sqlite3_context*,int,sqlite3_value*) = 0;
object pArg = null;
FuncDef pNew;
int rc = 0;
string zLowerName;
string z;
/* Check to see the left operand is a column in a virtual table */
if ( NEVER( pExpr == null ) )
return pDef;
if ( pExpr.op != TK_COLUMN )
return pDef;
pTab = pExpr.pTab;
if ( NEVER( pTab == null ) )
return pDef;
if ( ( pTab.tabFlags & TF_Virtual ) == 0 )
return pDef;
pVtab = sqlite3GetVTable( db, pTab ).pVtab;
Debug.Assert( pVtab != null );
Debug.Assert( pVtab.pModule != null );
pMod = (sqlite3_module)pVtab.pModule;
if ( pMod.xFindFunction == null )
return pDef;
/* Call the xFindFunction method on the virtual table implementation
** to see if the implementation wants to overload this function
*/
zLowerName = pDef.zName;//sqlite3DbStrDup(db, pDef.zName);
if ( zLowerName != null )
{
//for(z=(unsigned char)zLowerName; *z; z++){
// *z = sqlite3UpperToLower[*z];
//}
rc = pMod.xFindFunction( pVtab, nArg, zLowerName.ToLowerInvariant(), ref xFunc, ref pArg );
sqlite3DbFree( db, ref zLowerName );
}
if ( rc == 0 )
{
return pDef;
}
/* Create a new ephemeral function definition for the overloaded
** function */
//sqlite3DbMallocZero(db, sizeof(*pNew)
// + sqlite3Strlen30(pDef.zName) + 1);
//if ( pNew == null )
//{
// return pDef;
//}
pNew = pDef.Copy();
pNew.zName = pDef.zName;
//pNew.zName = (char )&pNew[1];
//memcpy(pNew.zName, pDef.zName, sqlite3Strlen30(pDef.zName)+1);
pNew.xFunc = xFunc;
pNew.pUserData = pArg;
pNew.flags |= SQLITE_FUNC_EPHEM;
return pNew;
}
