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mpv/mpvcore/bstr.c
wm4 00f735d5cb bstr: make UTF-8 check stricter
Don't accept overlong sequences. Don't accept codepoints past the
maximum unicode codepoint. Don't accept the UTF-16 surrogate codepoints.

I'm not sure if there are more codepoints that are defined to be
invalid, but we just want to make libavcodec happy, so this is enough.

(libavcodec's subtitle converter checks for valid UTF-8 and throws up
and dies if it's not - now we want to use bstr_sanitize_utf8_latin1() to
force valid UTF-8, so the strictness of our UTF-8 parser has to match at
least that of the libavcodec's check.)

I'm not sure whether the min test is actually 100% correct.

Note that libavcodec also treats BOM codepoints as invalid. This is
definitely a bug: the BOM is really just "zero-width non-breaking space"
redefined by Microsoft, but it is perfectly valid to appear in the
middle of a string. Official Unicode has merely deprecated the old
usage of the BOM codepoint, and didn't make it illegal. Besides, the
string could be from the start of a file, so even this check doesn't
make sense even with libavcodec's insane logic. We don't copy this bug.
2013-08-15 23:40:03 +02:00

386 lines
10 KiB
C

/*
* This file is part of MPlayer.
*
* MPlayer is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* MPlayer is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <stdarg.h>
#include <libavutil/common.h>
#include "talloc.h"
#include "mpvcore/bstr.h"
int bstrcmp(struct bstr str1, struct bstr str2)
{
int ret = memcmp(str1.start, str2.start, FFMIN(str1.len, str2.len));
if (!ret) {
if (str1.len == str2.len)
return 0;
else if (str1.len > str2.len)
return 1;
else
return -1;
}
return ret;
}
int bstrcasecmp(struct bstr str1, struct bstr str2)
{
int ret = strncasecmp(str1.start, str2.start, FFMIN(str1.len, str2.len));
if (!ret) {
if (str1.len == str2.len)
return 0;
else if (str1.len > str2.len)
return 1;
else
return -1;
}
return ret;
}
int bstrchr(struct bstr str, int c)
{
for (int i = 0; i < str.len; i++)
if (str.start[i] == c)
return i;
return -1;
}
int bstrrchr(struct bstr str, int c)
{
for (int i = str.len - 1; i >= 0; i--)
if (str.start[i] == c)
return i;
return -1;
}
int bstrcspn(struct bstr str, const char *reject)
{
int i;
for (i = 0; i < str.len; i++)
if (strchr(reject, str.start[i]))
break;
return i;
}
int bstrspn(struct bstr str, const char *accept)
{
int i;
for (i = 0; i < str.len; i++)
if (!strchr(accept, str.start[i]))
break;
return i;
}
int bstr_find(struct bstr haystack, struct bstr needle)
{
for (int i = 0; i < haystack.len; i++)
if (bstr_startswith(bstr_splice(haystack, i, haystack.len), needle))
return i;
return -1;
}
struct bstr bstr_lstrip(struct bstr str)
{
while (str.len && isspace(*str.start)) {
str.start++;
str.len--;
}
return str;
}
struct bstr bstr_strip(struct bstr str)
{
str = bstr_lstrip(str);
while (str.len && isspace(str.start[str.len - 1]))
str.len--;
return str;
}
struct bstr bstr_split(struct bstr str, const char *sep, struct bstr *rest)
{
int start;
for (start = 0; start < str.len; start++)
if (!strchr(sep, str.start[start]))
break;
str = bstr_cut(str, start);
int end = bstrcspn(str, sep);
if (rest) {
*rest = bstr_cut(str, end);
}
return bstr_splice(str, 0, end);
}
// Unlike with bstr_split(), tok is a string, and not a set of char.
// If tok is in str, return true, and: concat(out_left, tok, out_right) == str
// Otherwise, return false, and set out_left==str, out_right==""
bool bstr_split_tok(bstr str, const char *tok, bstr *out_left, bstr *out_right)
{
bstr bsep = bstr0(tok);
int pos = bstr_find(str, bsep);
if (pos < 0)
pos = str.len;
*out_left = bstr_splice(str, 0, pos);
*out_right = bstr_cut(str, pos + bsep.len);
return pos != str.len;
}
struct bstr bstr_splice(struct bstr str, int start, int end)
{
if (start < 0)
start += str.len;
if (end < 0)
end += str.len;
end = FFMIN(end, str.len);
start = FFMAX(start, 0);
end = FFMAX(end, start);
str.start += start;
str.len = end - start;
return str;
}
long long bstrtoll(struct bstr str, struct bstr *rest, int base)
{
str = bstr_lstrip(str);
char buf[51];
int len = FFMIN(str.len, 50);
memcpy(buf, str.start, len);
buf[len] = 0;
char *endptr;
long long r = strtoll(buf, &endptr, base);
if (rest)
*rest = bstr_cut(str, endptr - buf);
return r;
}
double bstrtod(struct bstr str, struct bstr *rest)
{
str = bstr_lstrip(str);
char buf[101];
int len = FFMIN(str.len, 100);
memcpy(buf, str.start, len);
buf[len] = 0;
char *endptr;
double r = strtod(buf, &endptr);
if (rest)
*rest = bstr_cut(str, endptr - buf);
return r;
}
struct bstr *bstr_splitlines(void *talloc_ctx, struct bstr str)
{
if (str.len == 0)
return NULL;
int count = 0;
for (int i = 0; i < str.len; i++)
if (str.start[i] == '\n')
count++;
if (str.start[str.len - 1] != '\n')
count++;
struct bstr *r = talloc_array_ptrtype(talloc_ctx, r, count);
unsigned char *p = str.start;
for (int i = 0; i < count - 1; i++) {
r[i].start = p;
while (*p++ != '\n');
r[i].len = p - r[i].start;
}
r[count - 1].start = p;
r[count - 1].len = str.start + str.len - p;
return r;
}
struct bstr bstr_getline(struct bstr str, struct bstr *rest)
{
int pos = bstrchr(str, '\n');
if (pos < 0)
pos = str.len;
if (rest)
*rest = bstr_cut(str, pos + 1);
return bstr_splice(str, 0, pos + 1);
}
struct bstr bstr_strip_linebreaks(struct bstr str)
{
if (bstr_endswith0(str, "\r\n")) {
str = bstr_splice(str, 0, str.len - 2);
} else if (bstr_endswith0(str, "\n")) {
str = bstr_splice(str, 0, str.len - 1);
}
return str;
}
bool bstr_eatstart(struct bstr *s, struct bstr prefix)
{
if (!bstr_startswith(*s, prefix))
return false;
*s = bstr_cut(*s, prefix.len);
return true;
}
void bstr_lower(struct bstr str)
{
for (int i = 0; i < str.len; i++)
str.start[i] = tolower(str.start[i]);
}
int bstr_sscanf(struct bstr str, const char *format, ...)
{
char *ptr = bstrdup0(NULL, str);
va_list va;
va_start(va, format);
int ret = vsscanf(ptr, format, va);
va_end(va);
talloc_free(ptr);
return ret;
}
int bstr_parse_utf8_code_length(unsigned char b)
{
if (b < 128)
return 1;
int bytes = 7 - av_log2(b ^ 255);
return (bytes >= 2 && bytes <= 4) ? bytes : -1;
}
int bstr_decode_utf8(struct bstr s, struct bstr *out_next)
{
if (s.len == 0)
return -1;
unsigned int codepoint = s.start[0];
s.start++; s.len--;
if (codepoint >= 128) {
int bytes = bstr_parse_utf8_code_length(codepoint);
if (bytes < 0 || s.len < bytes - 1)
return -1;
codepoint &= 127 >> bytes;
for (int n = 1; n < bytes; n++) {
int tmp = (unsigned char)s.start[0];
if ((tmp & 0xC0) != 0x80)
return -1;
codepoint = (codepoint << 6) | (tmp & ~0xC0);
s.start++; s.len--;
}
if (codepoint > 0x10FFFF || (codepoint >= 0xD800 && codepoint <= 0xDFFF))
return -1;
// Overlong sequences - check taken from libavcodec.
// (The only reason we even bother with this is to make libavcodec's
// retarded subtitle utf-8 check happy.)
unsigned int min = bytes == 2 ? 0x80 : 1 << (5 * bytes - 4);
if (codepoint < min)
return -1;
}
if (out_next)
*out_next = s;
return codepoint;
}
int bstr_validate_utf8(struct bstr s)
{
while (s.len) {
if (bstr_decode_utf8(s, &s) < 0) {
// Try to guess whether the sequence was just cut-off.
unsigned int codepoint = (unsigned char)s.start[0];
int bytes = bstr_parse_utf8_code_length(codepoint);
if (bytes > 1 && s.len < 6) {
// Manually check validity of left bytes
for (int n = 1; n < bytes; n++) {
if (n >= s.len) {
// Everything valid until now - just cut off.
return -(bytes - s.len);
}
int tmp = (unsigned char)s.start[n];
if ((tmp & 0xC0) != 0x80)
break;
}
}
return -8;
}
}
return 0;
}
static void append_bstr(bstr *buf, bstr s)
{
buf->start = talloc_realloc(NULL, buf->start, unsigned char, buf->len + s.len);
memcpy(buf->start + buf->len, s.start, s.len);
buf->len += s.len;
}
struct bstr bstr_sanitize_utf8_latin1(void *talloc_ctx, struct bstr s)
{
bstr new = {0};
bstr left = s;
unsigned char *first_ok = s.start;
while (left.len) {
int r = bstr_decode_utf8(left, &left);
if (r < 0) {
append_bstr(&new, (bstr){first_ok, left.start - first_ok});
uint32_t codepoint = (unsigned char)left.start[0];
char data[8];
uint8_t tmp;
char *output = data;
PUT_UTF8(codepoint, tmp, *output++ = tmp;);
append_bstr(&new, (bstr){data, output - data});
left.start += 1;
left.len -= 1;
first_ok = left.start;
}
}
if (!new.start)
return s;
if (first_ok != left.start)
append_bstr(&new, (bstr){first_ok, left.start - first_ok});
// For convenience
append_bstr(&new, (bstr){"\0", 1});
new.len -= 1;
talloc_steal(talloc_ctx, new.start);
return new;
}
bool bstr_case_startswith(struct bstr s, struct bstr prefix)
{
struct bstr start = bstr_splice(s, 0, prefix.len);
return start.len == prefix.len && bstrcasecmp(start, prefix) == 0;
}
bool bstr_case_endswith(struct bstr s, struct bstr suffix)
{
struct bstr end = bstr_cut(s, -suffix.len);
return end.len == suffix.len && bstrcasecmp(end, suffix) == 0;
}
struct bstr bstr_strip_ext(struct bstr str)
{
int dotpos = bstrrchr(str, '.');
if (dotpos < 0)
return str;
return (struct bstr){str.start, dotpos};
}
struct bstr bstr_get_ext(struct bstr s)
{
int dotpos = bstrrchr(s, '.');
if (dotpos < 0)
return (struct bstr){NULL, 0};
return bstr_splice(s, dotpos + 1, s.len);
}