| /* |
| * PNM image parser |
| * Copyright (c) 2002, 2003 Fabrice Bellard |
| * |
| * 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 |
| */ |
| |
| #include "libavutil/avassert.h" |
| #include "libavutil/imgutils.h" |
| |
| #include "parser.h" //for ParseContext |
| #include "pnm.h" |
| |
| typedef struct PNMParseContext { |
| ParseContext pc; |
| int remaining_bytes; |
| int ascii_scan; |
| }PNMParseContext; |
| |
| static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx, |
| const uint8_t **poutbuf, int *poutbuf_size, |
| const uint8_t *buf, int buf_size) |
| { |
| PNMParseContext *pnmpc = s->priv_data; |
| ParseContext *pc = &pnmpc->pc; |
| PNMContext pnmctx; |
| int next = END_NOT_FOUND; |
| int skip = 0; |
| |
| for (; pc->overread > 0; pc->overread--) { |
| pc->buffer[pc->index++]= pc->buffer[pc->overread_index++]; |
| } |
| |
| if (pnmpc->remaining_bytes) { |
| int inc = FFMIN(pnmpc->remaining_bytes, buf_size); |
| skip += inc; |
| pnmpc->remaining_bytes -= inc; |
| |
| if (!pnmpc->remaining_bytes) |
| next = skip; |
| goto end; |
| } |
| |
| retry: |
| if (pc->index) { |
| pnmctx.bytestream_start = |
| pnmctx.bytestream = pc->buffer; |
| pnmctx.bytestream_end = pc->buffer + pc->index; |
| } else { |
| pnmctx.bytestream_start = |
| pnmctx.bytestream = (uint8_t *) buf + skip; /* casts avoid warnings */ |
| pnmctx.bytestream_end = (uint8_t *) buf + buf_size - skip; |
| } |
| if (ff_pnm_decode_header(avctx, &pnmctx) < 0) { |
| if (pnmctx.bytestream < pnmctx.bytestream_end) { |
| if (pc->index) { |
| pc->index = 0; |
| pnmpc->ascii_scan = 0; |
| } else { |
| unsigned step = FFMAX(1, pnmctx.bytestream - pnmctx.bytestream_start); |
| |
| skip += step; |
| } |
| goto retry; |
| } |
| } else if (pnmctx.type < 4) { |
| uint8_t *bs = pnmctx.bytestream; |
| const uint8_t *end = pnmctx.bytestream_end; |
| uint8_t *sync = bs; |
| |
| if (pc->index) { |
| av_assert0(pnmpc->ascii_scan <= end - bs); |
| bs += pnmpc->ascii_scan; |
| } |
| |
| while (bs < end) { |
| int c; |
| sync = bs; |
| c = *bs++; |
| if (c == '#') { |
| while (c != '\n' && bs < end) |
| c = *bs++; |
| } else if (c == 'P') { |
| next = bs - pnmctx.bytestream_start + skip - 1; |
| pnmpc->ascii_scan = 0; |
| break; |
| } |
| } |
| if (next == END_NOT_FOUND) |
| pnmpc->ascii_scan = sync - pnmctx.bytestream + skip; |
| } else { |
| next = pnmctx.bytestream - pnmctx.bytestream_start + skip |
| + av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1); |
| } |
| if (next != END_NOT_FOUND && pnmctx.bytestream_start != buf + skip) |
| next -= pc->index; |
| if (next > buf_size) { |
| pnmpc->remaining_bytes = next - buf_size; |
| next = END_NOT_FOUND; |
| } |
| end: |
| if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
| *poutbuf = NULL; |
| *poutbuf_size = 0; |
| return buf_size; |
| } |
| *poutbuf = buf; |
| *poutbuf_size = buf_size; |
| return next; |
| } |
| |
| AVCodecParser ff_pnm_parser = { |
| .codec_ids = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM, |
| AV_CODEC_ID_PBM, AV_CODEC_ID_PAM }, |
| .priv_data_size = sizeof(PNMParseContext), |
| .parser_parse = pnm_parse, |
| .parser_close = ff_parse_close, |
| }; |