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Avoid using 'int' for UTF-8 values 

An 'int' may have only 16 bits, so it may not be big enough for UTF-8
values. The new type 'utfint' (in the utf8 library) ensures at least
21 bits for those values.
This commit is contained in:
Roberto Ierusalimschy 2018-07-12 15:56:44 -03:00
parent 96f9643f33
commit fb18346ddd
1 changed files with 22 additions and 11 deletions
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33
lutf8lib.c
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@ -1,5 +1,5 @@
/*
** $Id: lutf8lib.c,v 1.16 2016/12/22 13:08:50 roberto Exp roberto $
** $Id: lutf8lib.c $
** Standard library for UTF-8 manipulation
** See Copyright Notice in lua.h
*/
@ -20,8 +20,19 @@
#include "lauxlib.h"
#include "lualib.h"
#define MAXUNICODE 0x10FFFF
/*
** Integer type for decoded UTF-8 values; MAXUNICODE needs 21 bits.
*/
#if LUAI_BITSINT >= 21
typedef unsigned int utfint;
#else
typedef unsigned long utfint;
#endif
#define iscont(p) ((*(p) & 0xC0) == 0x80)
@ -37,11 +48,11 @@ static lua_Integer u_posrelat (lua_Integer pos, size_t len) {
/*
** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid.
*/
static const char *utf8_decode (const char *o, int *val) {
static const char *utf8_decode (const char *o, utfint *val) {
static const unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};
const unsigned char *s = (const unsigned char *)o;
unsigned int c = s[0];
unsigned int res = 0; /* final result */
utfint res = 0; /* final result */
if (c < 0x80) /* ascii? */
res = c;
else {
@ -53,7 +64,7 @@ static const char *utf8_decode (const char *o, int *val) {
res = (res << 6) | (cc & 0x3F); /* add lower 6 bits from cont. byte */
c <<= 1; /* to test next bit */
}
res |= ((c & 0x7F) << (count * 5)); /* add first byte */
res |= ((utfint)(c & 0x7F) << (count * 5)); /* add first byte */
if (count > 3 || res > MAXUNICODE || res <= limits[count])
return NULL; /* invalid byte sequence */
s += count; /* skip continuation bytes read */
@ -69,8 +80,8 @@ static const char *utf8_decode (const char *o, int *val) {
** that interval
*/
static int utflen (lua_State *L) {
int n = 0;
size_t len;
lua_Integer n = 0; /* counter for the number of characters */
size_t len; /* string length in bytes */
const char *s = luaL_checklstring(L, 1, &len);
lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len);
@ -109,12 +120,12 @@ static int codepoint (lua_State *L) {
if (posi > pose) return 0; /* empty interval; return no values */
if (pose - posi >= INT_MAX) /* (lua_Integer -> int) overflow? */
return luaL_error(L, "string slice too long");
n = (int)(pose - posi) + 1;
n = (int)(pose - posi) + 1; /* upper bound for number of returns */
luaL_checkstack(L, n, "string slice too long");
n = 0;
se = s + pose;
n = 0; /* count the number of returns */
se = s + pose; /* string end */
for (s += posi - 1; s < se;) {
int code;
utfint code;
s = utf8_decode(s, &code);
if (s == NULL)
return luaL_error(L, "invalid UTF-8 code");
@ -211,7 +222,7 @@ static int iter_aux (lua_State *L) {
if (n >= (lua_Integer)len)
return 0; /* no more codepoints */
else {
int code;
utfint code;
const char *next = utf8_decode(s + n, &code);
if (next == NULL || iscont(next))
return luaL_error(L, "invalid UTF-8 code");