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
28 typedef struct PNMParseContext {
29 ParseContext pc;
30 int remaining_bytes;
31 int ascii_scan;
32 }PNMParseContext;
33
pnm_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)34 static 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
61 retry:
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 && next + (uint64_t)ret <= INT_MAX)
115 next += ret;
116 }
117 if (next != END_NOT_FOUND && pnmctx.bytestream_start != buf + skip)
118 next -= pc->index;
119 if (next > buf_size) {
120 pnmpc->remaining_bytes = next - buf_size;
121 next = END_NOT_FOUND;
122 }
123 end:
124 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
125 *poutbuf = NULL;
126 *poutbuf_size = 0;
127 return buf_size;
128 }
129 *poutbuf = buf;
130 *poutbuf_size = buf_size;
131 return next;
132 }
133
134 AVCodecParser ff_pnm_parser = {
135 .codec_ids = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,
136 AV_CODEC_ID_PBM, AV_CODEC_ID_PAM },
137 .priv_data_size = sizeof(PNMParseContext),
138 .parser_parse = pnm_parse,
139 .parser_close = ff_parse_close,
140 };
141