113 lines
3.4 KiB
C
Executable File
113 lines
3.4 KiB
C
Executable File
/*
|
|
* WebP parser
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* WebP parser
|
|
*/
|
|
|
|
#include "libavutil/bswap.h"
|
|
#include "libavutil/common.h"
|
|
|
|
#include "parser.h"
|
|
|
|
typedef struct WebPParseContext {
|
|
ParseContext pc;
|
|
uint32_t fsize;
|
|
uint32_t remaining_size;
|
|
} WebPParseContext;
|
|
|
|
static int webp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
|
|
const uint8_t **poutbuf, int *poutbuf_size,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
WebPParseContext *ctx = s->priv_data;
|
|
uint64_t state = ctx->pc.state64;
|
|
int next = END_NOT_FOUND;
|
|
int i = 0;
|
|
|
|
*poutbuf = NULL;
|
|
*poutbuf_size = 0;
|
|
|
|
restart:
|
|
if (ctx->pc.frame_start_found <= 8) {
|
|
for (; i < buf_size; i++) {
|
|
state = (state << 8) | buf[i];
|
|
if (ctx->pc.frame_start_found == 0) {
|
|
if ((state >> 32) == MKBETAG('R', 'I', 'F', 'F')) {
|
|
ctx->fsize = av_bswap32(state);
|
|
if (ctx->fsize > 15 && ctx->fsize <= UINT32_MAX - 10) {
|
|
ctx->pc.frame_start_found = 1;
|
|
ctx->fsize += 8;
|
|
}
|
|
}
|
|
} else if (ctx->pc.frame_start_found == 8) {
|
|
if ((state >> 32) != MKBETAG('W', 'E', 'B', 'P')) {
|
|
ctx->pc.frame_start_found = 0;
|
|
continue;
|
|
}
|
|
ctx->pc.frame_start_found++;
|
|
ctx->remaining_size = ctx->fsize + i - 15;
|
|
if (ctx->pc.index + i > 15) {
|
|
next = i - 15;
|
|
state = 0;
|
|
break;
|
|
} else {
|
|
ctx->pc.state64 = 0;
|
|
goto restart;
|
|
}
|
|
} else if (ctx->pc.frame_start_found)
|
|
ctx->pc.frame_start_found++;
|
|
}
|
|
ctx->pc.state64 = state;
|
|
} else {
|
|
if (ctx->remaining_size) {
|
|
i = FFMIN(ctx->remaining_size, buf_size);
|
|
ctx->remaining_size -= i;
|
|
if (ctx->remaining_size)
|
|
goto flush;
|
|
|
|
ctx->pc.frame_start_found = 0;
|
|
goto restart;
|
|
}
|
|
}
|
|
|
|
flush:
|
|
if (ff_combine_frame(&ctx->pc, next, &buf, &buf_size) < 0)
|
|
return buf_size;
|
|
|
|
if (next != END_NOT_FOUND && next < 0)
|
|
ctx->pc.frame_start_found = FFMAX(ctx->pc.frame_start_found - i - 1, 0);
|
|
else
|
|
ctx->pc.frame_start_found = 0;
|
|
|
|
*poutbuf = buf;
|
|
*poutbuf_size = buf_size;
|
|
|
|
return next;
|
|
}
|
|
|
|
AVCodecParser ff_webp_parser = {
|
|
.codec_ids = { AV_CODEC_ID_WEBP },
|
|
.priv_data_size = sizeof(WebPParseContext),
|
|
.parser_parse = webp_parse,
|
|
.parser_close = ff_parse_close,
|
|
};
|