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
29static int convert(uint8_t x)
30{
31    if (x >= 'a')
32        x -= 87;
33    else if (x >= 'A')
34        x -= 55;
35    else
36        x -= '0';
37    return x;
38}
39
40static int parse_str_int(const uint8_t *p, int len, const uint8_t *key)
41{
42    const uint8_t *end = p + len;
43
44    for(; p<end - strlen(key); p++) {
45        if (!memcmp(p, key, strlen(key)))
46            break;
47    }
48    p += strlen(key);
49    if (p >= end)
50        return INT_MIN;
51
52    for(; p<end; p++) {
53        char *eptr;
54        int64_t ret = strtol(p, &eptr, 10);
55        if ((const uint8_t *)eptr != p)
56            return ret;
57    }
58    return INT_MIN;
59}
60
61static int xbm_decode_frame(AVCodecContext *avctx, void *data,
62                            int *got_frame, AVPacket *avpkt)
63{
64    AVFrame *p = data;
65    int ret, linesize, i, j;
66    int width  = 0;
67    int height = 0;
68    const uint8_t *end, *ptr = avpkt->data;
69    const uint8_t *next;
70    uint8_t *dst;
71
72    avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
73    end = avpkt->data + avpkt->size;
74
75    width  = parse_str_int(avpkt->data, avpkt->size, "_width");
76    height = parse_str_int(avpkt->data, avpkt->size, "_height");
77
78    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
79        return ret;
80
81    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
82        return ret;
83
84    // goto start of image data
85    next = memchr(ptr, '{', avpkt->size);
86    if (!next)
87        next = memchr(ptr, '(', avpkt->size);
88    if (!next)
89        return AVERROR_INVALIDDATA;
90    ptr = next + 1;
91
92    linesize = (avctx->width + 7) / 8;
93    for (i = 0; i < avctx->height; i++) {
94        dst = p->data[0] + i * p->linesize[0];
95        for (j = 0; j < linesize; j++) {
96            uint8_t val;
97
98            while (ptr < end && *ptr != 'x' && *ptr != '$')
99                ptr++;
100
101            ptr ++;
102            if (ptr < end && av_isxdigit(*ptr)) {
103                val = convert(*ptr++);
104                if (av_isxdigit(*ptr))
105                    val = (val << 4) + convert(*ptr++);
106                *dst++ = ff_reverse[val];
107                if (av_isxdigit(*ptr) && j+1 < linesize) {
108                    j++;
109                    val = convert(*ptr++);
110                    if (av_isxdigit(*ptr))
111                        val = (val << 4) + convert(*ptr++);
112                    *dst++ = ff_reverse[val];
113                }
114            } else {
115                av_log(avctx, AV_LOG_ERROR,
116                       "Unexpected data at %.8s.\n", ptr);
117                return AVERROR_INVALIDDATA;
118            }
119        }
120    }
121
122    p->key_frame = 1;
123    p->pict_type = AV_PICTURE_TYPE_I;
124
125    *got_frame       = 1;
126
127    return avpkt->size;
128}
129
130AVCodec ff_xbm_decoder = {
131    .name         = "xbm",
132    .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
133    .type         = AVMEDIA_TYPE_VIDEO,
134    .id           = AV_CODEC_ID_XBM,
135    .decode       = xbm_decode_frame,
136    .capabilities = CODEC_CAP_DR1,
137};
138