1/*
2 * PNM image parser
3 * Copyright (c) 2002, 2003 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/avassert.h"
23#include "libavutil/imgutils.h"
24
25#include "parser.h" //for ParseContext
26#include "pnm.h"
27
28typedef struct PNMParseContext {
29    ParseContext pc;
30    int remaining_bytes;
31    int ascii_scan;
32}PNMParseContext;
33
34static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
35                     const uint8_t **poutbuf, int *poutbuf_size,
36                     const uint8_t *buf, int buf_size)
37{
38    PNMParseContext *pnmpc = s->priv_data;
39    ParseContext *pc = &pnmpc->pc;
40    PNMContext pnmctx;
41    int next = END_NOT_FOUND;
42    int skip = 0;
43
44    if (pc->overread > 0) {
45        memmove(pc->buffer + pc->index, pc->buffer + pc->overread_index, pc->overread);
46        pc->index          += pc->overread;
47        pc->overread_index += pc->overread;
48        pc->overread = 0;
49    }
50
51    if (pnmpc->remaining_bytes) {
52        int inc = FFMIN(pnmpc->remaining_bytes, buf_size);
53        skip += inc;
54        pnmpc->remaining_bytes -= inc;
55
56        if (!pnmpc->remaining_bytes)
57            next = skip;
58        goto end;
59    }
60
61retry:
62    if (pc->index) {
63        pnmctx.bytestream_start =
64        pnmctx.bytestream       = pc->buffer;
65        pnmctx.bytestream_end   = pc->buffer + pc->index;
66    } else {
67        pnmctx.bytestream_start =
68        pnmctx.bytestream       = (uint8_t *) buf + skip; /* casts avoid warnings */
69        pnmctx.bytestream_end   = (uint8_t *) buf + buf_size - skip;
70    }
71    if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
72        if (pnmctx.bytestream < pnmctx.bytestream_end) {
73            if (pc->index) {
74                pc->index = 0;
75                pnmpc->ascii_scan = 0;
76            } else {
77                unsigned step = FFMAX(1, pnmctx.bytestream - pnmctx.bytestream_start);
78
79                skip += step;
80            }
81            goto retry;
82        }
83    } else if (pnmctx.type < 4) {
84              uint8_t *bs  = pnmctx.bytestream;
85        const uint8_t *end = pnmctx.bytestream_end;
86        uint8_t *sync      = bs;
87
88        if (pc->index) {
89            av_assert0(pnmpc->ascii_scan <= end - bs);
90            bs += pnmpc->ascii_scan;
91        }
92
93        while (bs < end) {
94            int c;
95            sync = bs;
96            c = *bs++;
97            if (c == '#')  {
98                uint8_t *match = memchr(bs, '\n', end-bs);
99                if (match)
100                    bs = match + 1;
101                else
102                    break;
103            } else if (c == 'P') {
104                next = bs - pnmctx.bytestream_start + skip - 1;
105                pnmpc->ascii_scan = 0;
106                break;
107            }
108        }
109        if (next == END_NOT_FOUND)
110            pnmpc->ascii_scan = sync - pnmctx.bytestream + skip;
111    } else {
112        int ret = av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
113        next = pnmctx.bytestream - pnmctx.bytestream_start + skip;
114        if (ret > 0 && pnmctx.half)
115            ret >>= 1;
116        if (ret >= 0 && next + (uint64_t)ret <= INT_MAX)
117            next += ret;
118    }
119    if (next != END_NOT_FOUND && pnmctx.bytestream_start != buf + skip)
120        next -= pc->index;
121    if (next > buf_size) {
122        pnmpc->remaining_bytes = next - buf_size;
123        next = END_NOT_FOUND;
124    }
125end:
126    if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
127        *poutbuf      = NULL;
128        *poutbuf_size = 0;
129        return buf_size;
130    }
131    *poutbuf      = buf;
132    *poutbuf_size = buf_size;
133    return next;
134}
135
136const AVCodecParser ff_pnm_parser = {
137    .codec_ids      = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,
138                        AV_CODEC_ID_PBM, AV_CODEC_ID_PAM, AV_CODEC_ID_PFM,
139                        AV_CODEC_ID_PHM },
140    .priv_data_size = sizeof(PNMParseContext),
141    .parser_parse   = pnm_parse,
142    .parser_close   = ff_parse_close,
143};
144