rusefi
/
lua
mirror of https://github.com/rusefi/lua.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

using unsigned int (instead of int) in 'table.sort' to avoid overflows 

(when computing the pivot and in original table size)
This commit is contained in:
Roberto Ierusalimschy 2015-11-23 09:17:31 -02:00
parent dc9ac5b8c2
commit c231a5e2b6
1 changed files with 23 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
ltablib.c
View File

@ -1,5 +1,5 @@
/*
** $Id: ltablib.c,v 1.86 2015/11/20 12:30:20 roberto Exp roberto $
** $Id: ltablib.c,v 1.87 2015/11/23 11:09:27 roberto Exp roberto $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
@ -230,7 +230,7 @@ static int unpack (lua_State *L) {
** =======================================================
*/
static void set2 (lua_State *L, int i, int j) {
static void set2 (lua_State *L, unsigned int i, unsigned int j) {
lua_seti(L, 1, i);
lua_seti(L, 1, j);
}
@ -258,9 +258,10 @@ static int sort_comp (lua_State *L, int a, int b) {
** Pos-condition: a[lo .. i - 1] <= a[i] == P <= a[i + 1 .. up]
** returns 'i'.
*/
static int partition (lua_State *L, int lo, int up) {
int i = lo; /* will be incremented before first use */
int j = up - 1; /* will be decremented before first use */
static unsigned int partition (lua_State *L, unsigned int lo,
unsigned int up) {
unsigned int i = lo; /* will be incremented before first use */
unsigned int j = up - 1; /* will be decremented before first use */
/* loop invariant: a[lo .. i] <= P <= a[j .. up] */
for (;;) {
/* next loop: repeat ++i while a[i] < P */
@ -292,28 +293,30 @@ static int partition (lua_State *L, int lo, int up) {
/*
** Choose a "random" pivot in the middle part of the interval [lo, up].
** (If you don't want/need this "randomness", (lo+up)/2 is an excelent
** (If you don't want/need this "randomness", (lo+up)/2 is an excellent
** choice.)
*/
#if !defined(l_sortpivot)
/* Use 'time' and 'clock' as sources of "randomness" */
#include <time.h>
static int choosePivot (int lo, int up) {
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 */
unsigned int r4 = (unsigned int)(up - lo) / 4u; /* range/4 */
unsigned int p = (c + t) % (r4 * 2) + (lo + r4);
lua_assert(lo + r4 <= p && p <= up - r4);
return (int)p;
return p;
}
#define l_sortpivot(lo,up) choosePivot(lo,up)
#endif
static void auxsort (lua_State *L, int lo, int up) {
static void auxsort (lua_State *L, unsigned int lo, unsigned int up) {
while (lo < up) { /* loop for tail recursion */
int p; /* Pivot index */
unsigned int p; /* Pivot index */
/* sort elements 'lo', 'p', and 'up' */
lua_geti(L, 1, lo);
lua_geti(L, 1, up);
@ -323,7 +326,7 @@ static void auxsort (lua_State *L, int lo, int up) {
lua_pop(L, 2); /* remove both values */
if (up - lo == 1) /* only 2 elements? */
return; /* already sorted */
if (up - lo < 100) /* small interval? */
if (up - lo < 100u) /* small interval? */
p = (lo + up)/2; /* middle element is a good pivot */
else /* for larger intervals, it is worth a random pivot */
p = l_sortpivot(lo, up);
@ -360,12 +363,15 @@ static void auxsort (lua_State *L, int lo, int up) {
static int sort (lua_State *L) {
int n = (int)aux_getn(L, 1, TAB_RW);
luaL_checkstack(L, 50, ""); /* assume array is smaller than 2^50 */
if (!lua_isnoneornil(L, 2)) /* is there a 2nd argument? */
luaL_checktype(L, 2, LUA_TFUNCTION);
lua_settop(L, 2); /* make sure there are two arguments */
auxsort(L, 1, n);
lua_Integer n = aux_getn(L, 1, TAB_RW);
if (n > 1) { /* non-trivial interval? */
luaL_argcheck(L, n < INT_MAX, 1, "array too big");
luaL_checkstack(L, 40, ""); /* assume array is smaller than 2^40 */
if (!lua_isnoneornil(L, 2)) /* is there a 2nd argument? */
luaL_checktype(L, 2, LUA_TFUNCTION); /* must be a function */
lua_settop(L, 2); /* make sure there are two arguments */
auxsort(L, 1, (unsigned int)n);
}
return 0;
}