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handling 'clock_t' and 'time_t' correctly in ISO C point of view

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Roberto Ierusalimschy 2015-11-24 14:54:32 -02:00
parent 71344b5cac
commit 7dc3ca7b8e
1 changed files with 14 additions and 5 deletions
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19
ltablib.c
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@ -1,5 +1,5 @@
/*
** $Id: ltablib.c,v 1.87 2015/11/23 11:09:27 roberto Exp roberto $
** $Id: ltablib.c,v 1.86 2015/11/20 12:30:20 roberto Exp roberto $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
@ -12,6 +12,7 @@
#include <limits.h>
#include <stddef.h>
#include <string.h>
#include "lua.h"
@ -298,14 +299,22 @@ static unsigned int partition (lua_State *L, unsigned int lo,
*/
#if !defined(l_sortpivot)
/* Use 'time' and 'clock' as sources of "randomness" */
#include <time.h>
#define szi (sizeof(unsigned int))
#define sof(e) (sizeof(e)/szi)
static unsigned int choosePivot (unsigned int lo, unsigned int up) {
unsigned int t = (unsigned int)(unsigned long)time(NULL); /* time */
unsigned int c = (unsigned int)(unsigned long)clock(); /* clock */
clock_t c = clock();
time_t t = time(NULL);
unsigned int buff[sof(c) + sof(t)];
unsigned int r4 = (unsigned int)(up - lo) / 4u; /* range/4 */
unsigned int p = (c + t) % (r4 * 2) + (lo + r4);
unsigned int p, i, h = 0;
memcpy(buff, &c, sof(c) * szi);
memcpy(buff + sof(c), &t, sof(t) * szi);
for (i = 0; i < sof(buff); i++)
h += buff[i];
p = h % (r4 * 2) + (lo + r4);
lua_assert(lo + r4 <= p && p <= up - r4);
return p;
}