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/*-------------------------------------------------------------------------
*
* tuplesort.h
* Generalized tuple sorting routines.
*
* This module handles sorting of heap tuples, index tuples, or single
* Datums (and could easily support other kinds of sortable objects,
* if necessary). It works efficiently for both small and large amounts
* of data. Small amounts are sorted in-memory using qsort(). Large
* amounts are sorted using temporary files and a standard external sort
* algorithm.
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: tuplesort.h,v 1.5 2000/06/15 03:33:11 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef TUPLESORT_H
#define TUPLESORT_H
#include "access/htup.h"
#include "access/itup.h"
/* Tuplesortstate is an opaque type whose details are not known outside tuplesort.c. */
typedef struct Tuplesortstate Tuplesortstate;
/*
* We provide two different interfaces to what is essentially the same
* code: one for sorting HeapTuples and one for sorting IndexTuples.
* They differ primarily in the way that the sort key information is
* supplied.
* Yet a third slightly different interface supports sorting bare Datums.
*/
extern Tuplesortstate *tuplesort_begin_heap(TupleDesc tupDesc,
int nkeys, ScanKey keys,
bool randomAccess);
extern Tuplesortstate *tuplesort_begin_index(Relation indexRel,
bool enforceUnique,
bool randomAccess);
extern Tuplesortstate *tuplesort_begin_datum(Oid datumType,
Oid sortOperator,
bool randomAccess);
extern void tuplesort_puttuple(Tuplesortstate *state, void *tuple);
extern void tuplesort_putdatum(Tuplesortstate *state, Datum val,
bool isNull);
extern void tuplesort_performsort(Tuplesortstate *state);
extern void *tuplesort_gettuple(Tuplesortstate *state, bool forward,
bool *should_free);
#define tuplesort_getheaptuple(state, forward, should_free) \
((HeapTuple) tuplesort_gettuple(state, forward, should_free))
#define tuplesort_getindextuple(state, forward, should_free) \
((IndexTuple) tuplesort_gettuple(state, forward, should_free))
extern bool tuplesort_getdatum(Tuplesortstate *state, bool forward,
Datum *val, bool *isNull);
extern void tuplesort_end(Tuplesortstate *state);
/*
* These routines may only be called if randomAccess was specified 'true'.
* Likewise, backwards scan in gettuple/getdatum is only allowed if
* randomAccess was specified.
*/
extern void tuplesort_rescan(Tuplesortstate *state);
extern void tuplesort_markpos(Tuplesortstate *state);
extern void tuplesort_restorepos(Tuplesortstate *state);
#endif /* TUPLESORT_H */
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