101 lines
2.0 KiB
C
101 lines
2.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* misc.c--
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*
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/misc.c,v 1.3 1996/07/22 21:56:02 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <sys/file.h>
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#include "postgres.h"
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#include "utils/datum.h"
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#include "catalog/pg_type.h"
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#include "utils/builtins.h"
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#if !defined(PORTNAME_aix) && \
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!defined(PORTNAME_BSD44_derived) && \
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!defined(PORTNAME_bsdi) && \
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!defined(PORTNAME_bsdi_2_1) && \
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!defined(PORTNAME_irix5) && \
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!defined(PORTNAME_linux)
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extern int random();
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extern int srandom(unsigned);
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#endif
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/*-------------------------------------------------------------------------
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* Check if data is Null
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*/
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bool
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NullValue(Datum value, bool *isNull)
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{
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if (*isNull) {
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*isNull = false;
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return(true);
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}
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return(false);
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}
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/*----------------------------------------------------------------------*
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* check if data is not Null *
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*--------------------------------------------------------------------- */
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bool
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NonNullValue(Datum value, bool *isNull)
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{
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if (*isNull) {
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*isNull = false;
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return(false);
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}
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return(true);
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}
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/*
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* oidrand (oid o, int4 X)-
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* takes in an oid and a int4 X, and will return 'true'
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* about 1/X of the time.
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* Useful for doing random sampling or subsetting.
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* if X == 0, this will always return true;
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*
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* Example use:
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* select * from TEMP where oidrand(TEMP.oid, 10)
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* will return about 1/10 of the tuples in TEMP
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*
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*/
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bool
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oidrand(Oid o, int32 X)
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{
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bool result;
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if (X == 0) return true;
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result = (random() % X == 0);
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return result;
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}
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/*
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oidsrand(int32 X) -
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seeds the random number generator
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always return true
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*/
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bool
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oidsrand(int32 X)
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{
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srand(X);
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return true;
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}
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int32
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userfntest(int i)
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{
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return (i);
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}
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