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"strsub" accepts negative indices (count from the end of the string).

This commit is contained in:
Roberto Ierusalimschy 1997-06-16 17:29:59 -03:00
parent 4d2de484f6
commit 1848bcc15b
1 changed files with 6 additions and 3 deletions
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9
strlib.c
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@ -3,7 +3,7 @@
** String library to LUA
*/
char *rcs_strlib="$Id: strlib.c,v 1.40 1997/04/06 14:08:08 roberto Exp roberto $";
char *rcs_strlib="$Id: strlib.c,v 1.41 1997/04/06 14:17:06 roberto Exp roberto $";
#include <string.h>
#include <stdio.h>
@ -106,9 +106,12 @@ static void str_len (void)
static void str_sub (void)
{
char *s = luaL_check_string(1);
long l = strlen(s);
long start = (long)luaL_check_number(2);
long end = (long)luaL_opt_number(3, strlen(s));
if (1 <= start && start <= end && end <= strlen(s)) {
long end = (long)luaL_opt_number(3, -1);
if (start < 0) start = l+start+1;
if (end < 0) end = l+end+1;
if (1 <= start && start <= end && end <= l) {
luaI_emptybuff();
addnchar(s+start-1, end-start+1);
lua_pushstring(luaI_addchar(0));