1 /*-------------------------------------------------------------------------
4 * Generalized tuple sorting routines.
6 * This module handles sorting of heap tuples, index tuples, or single
7 * Datums (and could easily support other kinds of sortable objects,
8 * if necessary). It works efficiently for both small and large amounts
9 * of data. Small amounts are sorted in-memory using qsort(). Large
10 * amounts are sorted using temporary files and a standard external sort
13 * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
14 * Portions Copyright (c) 1994, Regents of the University of California
16 * $Id: tuplesort.h,v 1.4 2000/04/12 17:16:56 momjian Exp $
18 *-------------------------------------------------------------------------
23 #include "access/htup.h"
24 #include "access/itup.h"
25 #include "access/skey.h"
26 #include "access/tupdesc.h"
27 #include "utils/rel.h"
29 /* Tuplesortstate is an opaque type whose details are not known outside tuplesort.c. */
31 typedef struct Tuplesortstate Tuplesortstate;
34 * We provide two different interfaces to what is essentially the same
35 * code: one for sorting HeapTuples and one for sorting IndexTuples.
36 * They differ primarily in the way that the sort key information is
38 * Yet a third slightly different interface supports sorting bare Datums.
41 extern Tuplesortstate *tuplesort_begin_heap(TupleDesc tupDesc,
42 int nkeys, ScanKey keys,
44 extern Tuplesortstate *tuplesort_begin_index(Relation indexRel,
47 extern Tuplesortstate *tuplesort_begin_datum(Oid datumType,
51 extern void tuplesort_puttuple(Tuplesortstate *state, void *tuple);
53 extern void tuplesort_putdatum(Tuplesortstate *state, Datum val,
56 extern void tuplesort_performsort(Tuplesortstate *state);
58 extern void *tuplesort_gettuple(Tuplesortstate *state, bool forward,
61 #define tuplesort_getheaptuple(state, forward, should_free) \
62 ((HeapTuple) tuplesort_gettuple(state, forward, should_free))
63 #define tuplesort_getindextuple(state, forward, should_free) \
64 ((IndexTuple) tuplesort_gettuple(state, forward, should_free))
66 extern bool tuplesort_getdatum(Tuplesortstate *state, bool forward,
67 Datum *val, bool *isNull);
69 extern void tuplesort_end(Tuplesortstate *state);
72 * These routines may only be called if randomAccess was specified 'true'.
73 * Likewise, backwards scan in gettuple/getdatum is only allowed if
74 * randomAccess was specified.
77 extern void tuplesort_rescan(Tuplesortstate *state);
78 extern void tuplesort_markpos(Tuplesortstate *state);
79 extern void tuplesort_restorepos(Tuplesortstate *state);
81 #endif /* TUPLESORT_H */