btree_gist.c

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/*
 * contrib/btree_gist/btree_gist.c
 */
#include "postgres.h"
 
#include "access/cmptype.h"
#include "access/stratnum.h"
#include "utils/builtins.h"
 
PG_MODULE_MAGIC_EXT(
                    .name = "btree_gist",
                    .version = PG_VERSION
);
 
PG_FUNCTION_INFO_V1(gbt_decompress);
PG_FUNCTION_INFO_V1(gbtreekey_in);
PG_FUNCTION_INFO_V1(gbtreekey_out);
PG_FUNCTION_INFO_V1(gist_stratnum_btree);
 
/**************************************************
 * In/Out for keys
 **************************************************/
 
 
Datum
gbtreekey_in(PG_FUNCTION_ARGS)
{
    Oid         typioparam = PG_GETARG_OID(1);
 
    ereport(ERROR,
            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
             errmsg("cannot accept a value of type %s",
                    format_type_extended(typioparam, -1,
                                         FORMAT_TYPE_ALLOW_INVALID))));
 
    PG_RETURN_VOID();           /* keep compiler quiet */
}
 
Datum
gbtreekey_out(PG_FUNCTION_ARGS)
{
    /* Sadly, we do not receive any indication of the specific type */
    ereport(ERROR,
            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
             errmsg("cannot display a value of type %s", "gbtreekey?")));
 
    PG_RETURN_VOID();           /* keep compiler quiet */
}
 
 
/*
** GiST DeCompress methods
** do not do anything.
*/
Datum
gbt_decompress(PG_FUNCTION_ARGS)
{
    PG_RETURN_POINTER(PG_GETARG_POINTER(0));
}
 
/*
 * Returns the btree number for supported operators, otherwise invalid.
 */
Datum
gist_stratnum_btree(PG_FUNCTION_ARGS)
{
    CompareType cmptype = PG_GETARG_INT32(0);
 
    switch (cmptype)
    {
        case COMPARE_EQ:
            PG_RETURN_UINT16(BTEqualStrategyNumber);
        case COMPARE_LT:
            PG_RETURN_UINT16(BTLessStrategyNumber);
        case COMPARE_LE:
            PG_RETURN_UINT16(BTLessEqualStrategyNumber);
        case COMPARE_GT:
            PG_RETURN_UINT16(BTGreaterStrategyNumber);
        case COMPARE_GE:
            PG_RETURN_UINT16(BTGreaterEqualStrategyNumber);
        default:
            PG_RETURN_UINT16(InvalidStrategy);
    }
}