1 /*
2 * XBM image format
3 *
4 * Copyright (c) 2012 Paul B Mahol
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "libavutil/avstring.h"
24 #include "libavutil/reverse.h"
25
26 #include "avcodec.h"
27 #include "codec_internal.h"
28 #include "internal.h"
29 #include "mathops.h"
30
get_nibble(uint8_t x)31 static int get_nibble(uint8_t x)
32 {
33 int ret = 255;
34
35 if (x <= '9') {
36 if (x >= '0')
37 ret = x - '0';
38 } else if (x >= 'a') {
39 if (x <= 'f')
40 ret = x - ('a' - 10);
41 } else if (x >= 'A' && x <= 'F')
42 ret = x - ('A' - 10);
43 return ret;
44 }
45
parse_str_int(const uint8_t * p,const uint8_t * end,const uint8_t * key)46 static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t *key)
47 {
48 int keylen = strlen(key);
49 const uint8_t *e = end - keylen;
50
51 for(; p < e; p++) {
52 if (!memcmp(p, key, keylen))
53 break;
54 }
55 p += keylen;
56 if (p >= end)
57 return INT_MIN;
58
59 for(; p<end; p++) {
60 char *eptr;
61 int64_t ret = strtol(p, &eptr, 10);
62 if ((const uint8_t *)eptr != p)
63 return ret;
64 }
65 return INT_MIN;
66 }
67
xbm_decode_frame(AVCodecContext * avctx,AVFrame * p,int * got_frame,AVPacket * avpkt)68 static int xbm_decode_frame(AVCodecContext *avctx, AVFrame *p,
69 int *got_frame, AVPacket *avpkt)
70 {
71 int ret, linesize, i, j;
72 int width = 0;
73 int height = 0;
74 const uint8_t *end, *ptr = avpkt->data;
75 const uint8_t *next;
76 uint8_t *dst;
77
78 avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
79 end = avpkt->data + avpkt->size;
80
81 width = parse_str_int(avpkt->data, end, "_width");
82 height = parse_str_int(avpkt->data, end, "_height");
83
84 if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
85 return ret;
86
87 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
88 return ret;
89
90 // goto start of image data
91 next = memchr(ptr, '{', avpkt->size);
92 if (!next)
93 next = memchr(ptr, '(', avpkt->size);
94 if (!next)
95 return AVERROR_INVALIDDATA;
96 ptr = next + 1;
97
98 linesize = (avctx->width + 7) / 8;
99 for (i = 0; i < avctx->height; i++) {
100 dst = p->data[0] + i * p->linesize[0];
101 for (j = 0; j < linesize; j++) {
102 uint8_t nib, val;
103
104 while (ptr < end && *ptr != 'x' && *ptr != '$')
105 ptr++;
106
107 ptr ++;
108 if (ptr < end && (val = get_nibble(*ptr)) <= 15) {
109 ptr++;
110 if ((nib = get_nibble(*ptr)) <= 15) {
111 val = (val << 4) + nib;
112 ptr++;
113 }
114 *dst++ = ff_reverse[val];
115 if ((val = get_nibble(*ptr)) <= 15 && j+1 < linesize) {
116 j++;
117 ptr++;
118 if ((nib = get_nibble(*ptr)) <= 15) {
119 val = (val << 4) + nib;
120 ptr++;
121 }
122 *dst++ = ff_reverse[val];
123 }
124 } else {
125 av_log(avctx, AV_LOG_ERROR,
126 "Unexpected data at %.8s.\n", ptr);
127 return AVERROR_INVALIDDATA;
128 }
129 }
130 }
131
132 p->key_frame = 1;
133 p->pict_type = AV_PICTURE_TYPE_I;
134
135 *got_frame = 1;
136
137 return avpkt->size;
138 }
139
140 const FFCodec ff_xbm_decoder = {
141 .p.name = "xbm",
142 .p.long_name = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
143 .p.type = AVMEDIA_TYPE_VIDEO,
144 .p.id = AV_CODEC_ID_XBM,
145 .p.capabilities = AV_CODEC_CAP_DR1,
146 FF_CODEC_DECODE_CB(xbm_decode_frame),
147 };
148