static int32
gbt_textcmp(const bytea *a, const bytea *b)
{
return DatumGetInt32(DirectFunctionCall2Coll(bttextcmp,
DEFAULT_COLLATION_OID,
PointerGetDatum(a),
PointerGetDatum(b)));
}
static bool
gbt_textlt(const void *a, const void *b)
{
return DatumGetBool(DirectFunctionCall2Coll(text_lt,
DEFAULT_COLLATION_OID,
PointerGetDatum(a),
PointerGetDatum(b)));
}
static int32
gbt_textcmp(const void *a, const void *b, Oid collation)
{
return DatumGetInt32(DirectFunctionCall2Coll(bttextcmp,
collation,
PointerGetDatum(a),
PointerGetDatum(b)));
}
static bool
gbt_textlt(const void *a, const void *b, Oid collation)
{
return DatumGetBool(DirectFunctionCall2Coll(text_lt,
collation,
PointerGetDatum(a),
PointerGetDatum(b)));
}
/*
* Datum a is a value from extract_query method and for BTLess*
* strategy it is a left-most value. So, use original datum from QueryInfo
* to decide to stop scanning or not. Datum b is always from index.
*/
static Datum
gin_btree_compare_prefix(FunctionCallInfo fcinfo)
{
Datum a = PG_GETARG_DATUM(0);
Datum b = PG_GETARG_DATUM(1);
QueryInfo *data = (QueryInfo *) PG_GETARG_POINTER(3);
int32 res,
cmp;
cmp = DatumGetInt32(DirectFunctionCall2Coll(
data->typecmp,
PG_GET_COLLATION(),
(data->strategy == BTLessStrategyNumber ||
data->strategy == BTLessEqualStrategyNumber)
? data->datum : a,
b));
switch (data->strategy)
{
case BTLessStrategyNumber:
/* If original datum > indexed one then return match */
if (cmp > 0)
res = 0;
else
res = 1;
break;
case BTLessEqualStrategyNumber:
/* The same except equality */
if (cmp >= 0)
res = 0;
else
res = 1;
break;
case BTEqualStrategyNumber:
if (cmp != 0)
res = 1;
else
res = 0;
break;
case BTGreaterEqualStrategyNumber:
/* If original datum <= indexed one then return match */
if (cmp <= 0)
res = 0;
else
res = 1;
break;
case BTGreaterStrategyNumber:
/* If original datum <= indexed one then return match */
/* If original datum == indexed one then continue scan */
if (cmp < 0)
res = 0;
else if (cmp == 0)
res = -1;
else
res = 1;
break;
default:
elog(ERROR, "unrecognized strategy number: %d",
data->strategy);
res = 0;
}
PG_RETURN_INT32(res);
}
