/*
** $Id: lstrlib.c,v 1.132.1.5 2010/05/14 15:34:19 roberto Exp $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define lstrlib_c
#define LUA_LIB
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
/* macro to `unsign' a character */
#define uchar(c) ((unsigned char)(c))
static int str_len (lua_State *L) {
size_t l;
luaL_checklstring(L, 1, &l);
lua_pushinteger(L, l);
return 1;
}
static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {
/* relative string position: negative means back from end */
if (pos < 0) pos += (ptrdiff_t)len + 1;
return (pos >= 0) ? pos : 0;
}
static int str_sub (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);
ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);
if (start < 1) start = 1;
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