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/*-------------------------------------------------------------------------
*
* misc.c--
*
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/misc.c,v 1.13 1998/06/09 19:20:59 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <sys/types.h>
#include <sys/file.h>
#include <time.h>
#include "postgres.h"
#include "utils/datum.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
/*-------------------------------------------------------------------------
* Check if data is Null
*/
bool
nullvalue(Datum value, bool *isNull)
{
if (*isNull)
{
*isNull = false;
return (true);
}
return (false);
}
/*----------------------------------------------------------------------*
* check if data is not Null *
*--------------------------------------------------------------------- */
bool
nonnullvalue(Datum value, bool *isNull)
{
if (*isNull)
{
*isNull = false;
return (false);
}
return (true);
}
/*
* oidrand (oid o, int4 X)-
* takes in an oid and a int4 X, and will return 'true'
* about 1/X of the time.
* Useful for doing random sampling or subsetting.
* if X == 0, this will always return true;
*
* Example use:
* select * from TEMP where oidrand(TEMP.oid, 10)
* will return about 1/10 of the tuples in TEMP
*
*/
static bool random_initialized = false;
bool
oidrand(Oid o, int32 X)
{
bool result;
if (X == 0)
return true;
/*
* We do this because the cancel key is actually a random, so we don't
* want them to be able to request random numbers using our postmaster
* seeded value.
*/
if (!random_initialized)
{
srandom((unsigned int)time(NULL));
random_initialized = true;
}
result = (random() % X == 0);
return result;
}
/*
oidsrand(int32 X) -
seeds the random number generator
always return true
*/
bool
oidsrand(int32 X)
{
srand(X);
random_initialized = true;
return true;
}
int32
userfntest(int i)
{
return (i);
}
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