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
25 #include "avcodec.h"
26 #include "internal.h"
27 #include "mathops.h"
28
get_nibble(uint8_t x)29 static int get_nibble(uint8_t x)
30 {
31 int ret = 255;
32
33 if (x <= '9') {
34 if (x >= '0')
35 ret = x - '0';
36 } else if (x >= 'a') {
37 if (x <= 'f')
38 ret = x - ('a' - 10);
39 } else if (x >= 'A' && x <= 'F')
40 ret = x - ('A' - 10);
41 return ret;
42 }
43
parse_str_int(const uint8_t * p,const uint8_t * end,const uint8_t * key)44 static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t *key)
45 {
46 int keylen = strlen(key);
47 const uint8_t *e = end - keylen;
48
49 for(; p < e; p++) {
50 if (!memcmp(p, key, keylen))
51 break;
52 }
53 p += keylen;
54 if (p >= end)
55 return INT_MIN;
56
57 for(; p<end; p++) {
58 char *eptr;
59 int64_t ret = strtol(p, &eptr, 10);
60 if ((const uint8_t *)eptr != p)
61 return ret;
62 }
63 return INT_MIN;
64 }
65
xbm_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)66 static int xbm_decode_frame(AVCodecContext *avctx, void *data,
67 int *got_frame, AVPacket *avpkt)
68 {
69 AVFrame *p = data;
70 int ret, linesize, i, j;
71 int width = 0;
72 int height = 0;
73 const uint8_t *end, *ptr = avpkt->data;
74 const uint8_t *next;
75 uint8_t *dst;
76
77 avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
78 end = avpkt->data + avpkt->size;
79
80 width = parse_str_int(avpkt->data, end, "_width");
81 height = parse_str_int(avpkt->data, end, "_height");
82
83 if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
84 return ret;
85
86 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
87 return ret;
88
89 // goto start of image data
90 next = memchr(ptr, '{', avpkt->size);
91 if (!next)
92 next = memchr(ptr, '(', avpkt->size);
93 if (!next)
94 return AVERROR_INVALIDDATA;
95 ptr = next + 1;
96
97 linesize = (avctx->width + 7) / 8;
98 for (i = 0; i < avctx->height; i++) {
99 dst = p->data[0] + i * p->linesize[0];
100 for (j = 0; j < linesize; j++) {
101 uint8_t nib, val;
102
103 while (ptr < end && *ptr != 'x' && *ptr != '$')
104 ptr++;
105
106 ptr ++;
107 if (ptr < end && (val = get_nibble(*ptr)) <= 15) {
108 ptr++;
109 if ((nib = get_nibble(*ptr)) <= 15) {
110 val = (val << 4) + nib;
111 ptr++;
112 }
113 *dst++ = ff_reverse[val];
114 if ((val = get_nibble(*ptr)) <= 15 && j+1 < linesize) {
115 j++;
116 ptr++;
117 if ((nib = get_nibble(*ptr)) <= 15) {
118 val = (val << 4) + nib;
119 ptr++;
120 }
121 *dst++ = ff_reverse[val];
122 }
123 } else {
124 av_log(avctx, AV_LOG_ERROR,
125 "Unexpected data at %.8s.\n", ptr);
126 return AVERROR_INVALIDDATA;
127 }
128 }
129 }
130
131 p->key_frame = 1;
132 p->pict_type = AV_PICTURE_TYPE_I;
133
134 *got_frame = 1;
135
136 return avpkt->size;
137 }
138
139 AVCodec ff_xbm_decoder = {
140 .name = "xbm",
141 .long_name = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
142 .type = AVMEDIA_TYPE_VIDEO,
143 .id = AV_CODEC_ID_XBM,
144 .decode = xbm_decode_frame,
145 .capabilities = AV_CODEC_CAP_DR1,
146 };
147