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894995c41e
Fixes: [Semmle Security Reports #19439] Fixes: dos_sscanf2.mkv Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
320 lines
11 KiB
C
320 lines
11 KiB
C
/*
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* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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* Copyright (c) 2017 Clément Bœsch <u@pkh.me>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avassert.h"
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#include "libavutil/avstring.h"
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#include "libavutil/common.h"
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#include "libavutil/parseutils.h"
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#include "htmlsubtitles.h"
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#include <ctype.h>
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static int html_color_parse(void *log_ctx, const char *str)
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{
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uint8_t rgba[4];
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int nb_sharps = 0;
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while (str[nb_sharps] == '#')
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nb_sharps++;
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str += FFMAX(0, nb_sharps - 1);
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if (av_parse_color(rgba, str, strcspn(str, "\" >"), log_ctx) < 0)
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return -1;
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return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
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}
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static void rstrip_spaces_buf(AVBPrint *buf)
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{
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if (av_bprint_is_complete(buf))
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while (buf->len > 0 && buf->str[buf->len - 1] == ' ')
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buf->str[--buf->len] = 0;
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}
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/*
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* Fast code for scanning text enclosed in braces. Functionally
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* equivalent to this sscanf call:
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*
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* sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0
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*/
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static int scanbraces(const char* in) {
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if (strncmp(in, "{\\an", 4) != 0) {
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return 0;
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}
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if (!isdigit(in[4])) {
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return 0;
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}
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if (in[5] != '}') {
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return 0;
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}
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return 1;
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}
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/* skip all {\xxx} substrings except for {\an%d}
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and all microdvd like styles such as {Y:xxx} */
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static void handle_open_brace(AVBPrint *dst, const char **inp, int *an, int *closing_brace_missing)
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{
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const char *in = *inp;
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*an += scanbraces(in);
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if (!*closing_brace_missing) {
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if ( (*an != 1 && in[1] == '\\')
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|| (in[1] && strchr("CcFfoPSsYy", in[1]) && in[2] == ':')) {
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char *bracep = strchr(in+2, '}');
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if (bracep) {
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*inp = bracep;
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return;
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} else
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*closing_brace_missing = 1;
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}
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}
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av_bprint_chars(dst, *in, 1);
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}
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struct font_tag {
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char face[128];
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int size;
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uint32_t color;
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};
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/*
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* Fast code for scanning the rest of a tag. Functionally equivalent to
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* this sscanf call:
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*
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* sscanf(in, "%127[^<>]>%n", buffer, lenp) == 2
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*/
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static int scantag(const char* in, char* buffer, int* lenp) {
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int len;
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for (len = 0; len < 128; len++) {
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const char c = *in++;
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switch (c) {
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case '\0':
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return 0;
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case '<':
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return 0;
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case '>':
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buffer[len] = '\0';
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*lenp = len+1;
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return 1;
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default:
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break;
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}
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buffer[len] = c;
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}
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return 0;
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}
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/*
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* The general politic of the convert is to mask unsupported tags or formatting
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* errors (but still alert the user/subtitles writer with an error/warning)
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* without dropping any actual text content for the final user.
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*/
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int ff_htmlmarkup_to_ass(void *log_ctx, AVBPrint *dst, const char *in)
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{
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char *param, buffer[128];
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int len, tag_close, sptr = 0, line_start = 1, an = 0, end = 0;
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int closing_brace_missing = 0;
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int i, likely_a_tag;
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/*
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* state stack is only present for fonts since they are the only tags where
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* the state is not binary. Here is a typical use case:
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*
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* <font color="red" size=10>
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* red 10
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* <font size=50> RED AND BIG </font>
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* red 10 again
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* </font>
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*
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* On the other hand, using the state system for all the tags should be
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* avoided because it breaks wrongly nested tags such as:
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*
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* <b> foo <i> bar </b> bla </i>
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*
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* We don't want to break here; instead, we will treat all these tags as
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* binary state markers. Basically, "<b>" will activate bold, and "</b>"
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* will deactivate it, whatever the current state.
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*
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* This will also prevents cases where we have a random closing tag
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* remaining after the opening one was dropped. Yes, this happens and we
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* still don't want to print a "</b>" at the end of the dialog event.
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*/
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struct font_tag stack[16];
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memset(&stack[0], 0, sizeof(stack[0]));
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for (; !end && *in; in++) {
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switch (*in) {
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case '\r':
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break;
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case '\n':
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if (line_start) {
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end = 1;
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break;
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}
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rstrip_spaces_buf(dst);
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av_bprintf(dst, "\\N");
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line_start = 1;
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break;
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case ' ':
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if (!line_start)
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av_bprint_chars(dst, *in, 1);
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break;
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case '{':
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handle_open_brace(dst, &in, &an, &closing_brace_missing);
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break;
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case '<':
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/*
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* "<<" are likely latin guillemets in ASCII or some kind of random
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* style effect; see sub/badsyntax.srt in the FATE samples
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* directory for real test cases.
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*/
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likely_a_tag = 1;
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for (i = 0; in[1] == '<'; i++) {
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av_bprint_chars(dst, '<', 1);
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likely_a_tag = 0;
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in++;
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}
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tag_close = in[1] == '/';
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if (tag_close)
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likely_a_tag = 1;
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av_assert0(in[0] == '<');
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len = 0;
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if (scantag(in+tag_close+1, buffer, &len) && len > 0) {
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const int skip = len + tag_close;
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const char *tagname = buffer;
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while (*tagname == ' ') {
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likely_a_tag = 0;
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tagname++;
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}
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if ((param = strchr(tagname, ' ')))
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*param++ = 0;
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/* Check if this is likely a tag */
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#define LIKELY_A_TAG_CHAR(x) (((x) >= '0' && (x) <= '9') || \
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((x) >= 'a' && (x) <= 'z') || \
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((x) >= 'A' && (x) <= 'Z') || \
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(x) == '_' || (x) == '/')
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for (i = 0; tagname[i]; i++) {
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if (!LIKELY_A_TAG_CHAR(tagname[i])) {
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likely_a_tag = 0;
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break;
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}
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}
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if (!av_strcasecmp(tagname, "font")) {
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if (tag_close && sptr > 0) {
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struct font_tag *cur_tag = &stack[sptr--];
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struct font_tag *last_tag = &stack[sptr];
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if (cur_tag->size) {
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if (!last_tag->size)
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av_bprintf(dst, "{\\fs}");
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else if (last_tag->size != cur_tag->size)
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av_bprintf(dst, "{\\fs%d}", last_tag->size);
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}
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if (cur_tag->color & 0xff000000) {
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if (!(last_tag->color & 0xff000000))
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av_bprintf(dst, "{\\c}");
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else if (last_tag->color != cur_tag->color)
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av_bprintf(dst, "{\\c&H%"PRIX32"&}", last_tag->color & 0xffffff);
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}
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if (cur_tag->face[0]) {
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if (!last_tag->face[0])
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av_bprintf(dst, "{\\fn}");
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else if (strcmp(last_tag->face, cur_tag->face))
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av_bprintf(dst, "{\\fn%s}", last_tag->face);
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}
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} else if (!tag_close && sptr < FF_ARRAY_ELEMS(stack) - 1) {
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struct font_tag *new_tag = &stack[sptr + 1];
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*new_tag = stack[sptr++];
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while (param) {
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if (!av_strncasecmp(param, "size=", 5)) {
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param += 5 + (param[5] == '"');
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if (sscanf(param, "%u", &new_tag->size) == 1)
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av_bprintf(dst, "{\\fs%u}", new_tag->size);
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} else if (!av_strncasecmp(param, "color=", 6)) {
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int color;
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param += 6 + (param[6] == '"');
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color = html_color_parse(log_ctx, param);
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if (color >= 0) {
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new_tag->color = 0xff000000 | color;
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av_bprintf(dst, "{\\c&H%"PRIX32"&}", new_tag->color & 0xffffff);
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}
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} else if (!av_strncasecmp(param, "face=", 5)) {
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param += 5 + (param[5] == '"');
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len = strcspn(param,
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param[-1] == '"' ? "\"" :" ");
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av_strlcpy(new_tag->face, param,
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FFMIN(sizeof(new_tag->face), len+1));
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param += len;
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av_bprintf(dst, "{\\fn%s}", new_tag->face);
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}
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if ((param = strchr(param, ' ')))
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param++;
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}
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}
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in += skip;
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} else if (tagname[0] && !tagname[1] && strchr("bisu", av_tolower(tagname[0]))) {
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av_bprintf(dst, "{\\%c%d}", (char)av_tolower(tagname[0]), !tag_close);
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in += skip;
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} else if (!av_strncasecmp(tagname, "br", 2) &&
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(!tagname[2] || (tagname[2] == '/' && !tagname[3]))) {
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av_bprintf(dst, "\\N");
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in += skip;
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} else if (likely_a_tag) {
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if (!tag_close) // warn only once
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av_log(log_ctx, AV_LOG_WARNING, "Unrecognized tag %s\n", tagname);
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in += skip;
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} else {
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av_bprint_chars(dst, '<', 1);
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}
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} else {
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av_bprint_chars(dst, *in, 1);
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}
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break;
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default:
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av_bprint_chars(dst, *in, 1);
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break;
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}
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if (*in != ' ' && *in != '\r' && *in != '\n')
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line_start = 0;
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}
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if (!av_bprint_is_complete(dst))
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return AVERROR(ENOMEM);
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while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2))
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dst->len -= 2;
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dst->str[dst->len] = 0;
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rstrip_spaces_buf(dst);
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return 0;
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}
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