skipsupport.c File Reference

#include "postgres.h"
#include "access/nbtree.h"
#include "utils/lsyscache.h"
#include "utils/skipsupport.h"

Include dependency graph for skipsupport.c:

Go to the source code of this file.

Functions
SkipSupport	PrepareSkipSupportFromOpclass (Oid opfamily, Oid opcintype, bool reverse)

Function Documentation

PrepareSkipSupportFromOpclass()

SkipSupport PrepareSkipSupportFromOpclass	(	Oid	opfamily,
		Oid	opcintype,
		bool	reverse
	)

Definition at line 30 of file skipsupport.c.

{
    Oid         skipSupportFunction;
    SkipSupport sksup;
 
    /* Look for a skip support function */
    skipSupportFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
                                            BTSKIPSUPPORT_PROC);
    if (!OidIsValid(skipSupportFunction))
        return NULL;
 
    sksup = palloc(sizeof(SkipSupportData));
    OidFunctionCall1(skipSupportFunction, PointerGetDatum(sksup));
 
    if (reverse)
    {
        /*
         * DESC/reverse case: swap low_elem with high_elem, and swap decrement
         * with increment
         */
        Datum       low_elem = sksup->low_elem;
        SkipSupportIncDec decrement = sksup->decrement;
 
        sksup->low_elem = sksup->high_elem;
        sksup->decrement = sksup->increment;
 
        sksup->high_elem = low_elem;
        sksup->increment = decrement;
    }
 
    return sksup;
}

References BTSKIPSUPPORT_PROC, SkipSupportData::decrement, get_opfamily_proc(), SkipSupportData::high_elem, SkipSupportData::increment, SkipSupportData::low_elem, OidFunctionCall1, OidIsValid, palloc(), and PointerGetDatum().

Referenced by _bt_preprocess_array_keys().