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src/backend/utils/adt/skipsupport.c
61 строка
2 KB
Bruce Momjian
Update copyright for 2026
01 янв 2026, 21:24
01 янв 2026, 21:24
451c439
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/*------------------------------------------------------------------------- * * skipsupport.c * Support routines for B-Tree skip scan. * * * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION * src/backend/utils/adt/skipsupport.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/nbtree.h" #include "utils/lsyscache.h" #include "utils/skipsupport.h" /* * Fill in SkipSupport given an operator class (opfamily + opcintype). * * On success, returns skip support struct, allocating in caller's memory * context. Otherwise returns NULL, indicating that operator class has no * skip support function. */ SkipSupport PrepareSkipSupportFromOpclass(Oid opfamily, Oid opcintype, bool reverse) { 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; }