geqo_random.c

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/*------------------------------------------------------------------------
 *
 * geqo_random.c
 *     random number generator
 *
 * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/backend/optimizer/geqo/geqo_random.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "postgres.h"
 
#include "optimizer/geqo_random.h"
 
 
void
geqo_set_seed(PlannerInfo *root, double seed)
{
    GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private;
 
    pg_prng_fseed(&private->random_state, seed);
}
 
double
geqo_rand(PlannerInfo *root)
{
    GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private;
 
    return pg_prng_double(&private->random_state);
}
 
int
geqo_randint(PlannerInfo *root, int upper, int lower)
{
    GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private;
 
    /*
     * In current usage, "lower" is never negative so we can just use
     * pg_prng_uint64_range directly.
     */
    return (int) pg_prng_uint64_range(&private->random_state, lower, upper);
}