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/*********************************************************************
* kd-forest *
* Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com> *
* *
* This program is free software. It comes without any warranty, to *
* the extent permitted by applicable law. You can redistribute it *
* and/or modify it under the terms of the Do What The Fuck You Want *
* To Public License, Version 2, as published by Sam Hocevar. See *
* the COPYING file or http://www.wtfpl.net/ for more details. *
*********************************************************************/
#include "util.h"
#include <stdlib.h>
void *
xmalloc(size_t size)
{
void *ret = malloc(size);
if (!ret) {
abort();
}
return ret;
}
void *
xrealloc(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
if (!ret) {
abort();
}
return ret;
}
// Based on sample rand() implementation from POSIX.1-2001
static unsigned long xrand_next = 0;
void xsrand(unsigned int seed) {
xrand_next = seed;
}
static unsigned int xrand_simple(void) {
xrand_next = xrand_next*1103515245 + 12345;
return (unsigned int)(xrand_next/65536)%32768;
}
static unsigned int xrand_full(void) {
unsigned int low = xrand_simple();
unsigned int high = xrand_simple();
return low | (high << 15);
}
#define XRAND_RANGE 1073741824U
unsigned int
xrand(unsigned int range)
{
// Compensate for bias if XRAND_RANGE isn't a multiple of range
unsigned int limit = XRAND_RANGE - XRAND_RANGE%range;
unsigned int res;
do {
res = xrand_full();
} while (res >= limit);
return res%range;
}
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