| /* |
| * 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, |
| }; |