aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/xbmdec.c
blob: c1fc6cb65004382ee00fd321bfe34983b7ab5a6d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
 * XBM image format
 *
 * Copyright (c) 2012 Paul B Mahol
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/avstring.h"

#include "avcodec.h"
#include "internal.h"
#include "mathops.h"

static int get_nibble(uint8_t x)
{
    int ret = 255;

    if (x <= '9') {
        if (x >= '0')
            ret = x - '0';
    } else if (x >= 'a') {
        if (x <= 'f')
            ret = x - ('a' - 10);
    } else if (x >= 'A' && x <= 'F')
        ret = x - ('A' - 10);
    return ret;
}

static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t *key)
{
    int keylen = strlen(key);
    const uint8_t *e = end - keylen;

    for(; p < e; p++) {
        if (!memcmp(p, key, keylen))
            break;
    }
    p += keylen;
    if (p >= end)
        return INT_MIN;

    for(; p<end; p++) {
        char *eptr;
        int64_t ret = strtol(p, &eptr, 10);
        if ((const uint8_t *)eptr != p)
            return ret;
    }
    return INT_MIN;
}

static int xbm_decode_frame(AVCodecContext *avctx, void *data,
                            int *got_frame, AVPacket *avpkt)
{
    AVFrame *p = data;
    int ret, linesize, i, j;
    int width  = 0;
    int height = 0;
    const uint8_t *end, *ptr = avpkt->data;
    const uint8_t *next;
    uint8_t *dst;

    avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
    end = avpkt->data + avpkt->size;

    width  = parse_str_int(avpkt->data, end, "_width");
    height = parse_str_int(avpkt->data, end, "_height");

    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
        return ret;

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
        return ret;

    // goto start of image data
    next = memchr(ptr, '{', avpkt->size);
    if (!next)
        next = memchr(ptr, '(', avpkt->size);
    if (!next)
        return AVERROR_INVALIDDATA;
    ptr = next + 1;

    linesize = (avctx->width + 7) / 8;
    for (i = 0; i < avctx->height; i++) {
        dst = p->data[0] + i * p->linesize[0];
        for (j = 0; j < linesize; j++) {
            uint8_t nib, val;

            while (ptr < end && *ptr != 'x' && *ptr != '$')
                ptr++;

            ptr ++;
            if (ptr < end && (val = get_nibble(*ptr)) <= 15) {
                ptr++;
                if ((nib = get_nibble(*ptr)) <= 15) {
                    val = (val << 4) + nib;
                    ptr++;
                }
                *dst++ = ff_reverse[val];
                if ((val = get_nibble(*ptr)) <= 15 && j+1 < linesize) {
                    j++;
                    ptr++;
                    if ((nib = get_nibble(*ptr)) <= 15) {
                        val = (val << 4) + nib;
                        ptr++;
                    }
                    *dst++ = ff_reverse[val];
                }
            } else {
                av_log(avctx, AV_LOG_ERROR,
                       "Unexpected data at %.8s.\n", ptr);
                return AVERROR_INVALIDDATA;
            }
        }
    }

    p->key_frame = 1;
    p->pict_type = AV_PICTURE_TYPE_I;

    *got_frame       = 1;

    return avpkt->size;
}

AVCodec ff_xbm_decoder = {
    .name         = "xbm",
    .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
    .type         = AVMEDIA_TYPE_VIDEO,
    .id           = AV_CODEC_ID_XBM,
    .decode       = xbm_decode_frame,
    .capabilities = AV_CODEC_CAP_DR1,
};