skipsupport.h File Reference

#include "utils/relcache.h"

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Data Structures
struct	SkipSupportData

Typedefs
typedef struct SkipSupportData *	SkipSupport
typedef Datum(*	SkipSupportIncDec) (Relation rel, Datum existing, bool *overflow)
typedef struct SkipSupportData	SkipSupportData

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

Typedef Documentation

SkipSupport

typedef struct SkipSupportData* SkipSupport

Definition at line 50 of file skipsupport.h.

SkipSupportData

typedef struct SkipSupportData SkipSupportData

SkipSupportIncDec

typedef Datum(* SkipSupportIncDec) (Relation rel, Datum existing, bool *overflow)

Definition at line 51 of file skipsupport.h.

Function Documentation

PrepareSkipSupportFromOpclass()

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

extern

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_object(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, fb(), get_opfamily_proc(), SkipSupportData::high_elem, SkipSupportData::increment, SkipSupportData::low_elem, OidFunctionCall1, OidIsValid, palloc_object, and PointerGetDatum().

Referenced by _bt_preprocess_array_keys().