aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/msrle.c
blob: fae5616e51e52dbcc69c8c82693338654d9055ca (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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
/*
 * Micrsoft RLE Video Decoder
 * Copyright (C) 2003 the ffmpeg project
 *
 * 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
 */

/**
 * @file msrle.c
 * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
 * For more information about the MS RLE format, visit:
 *   http://www.pcisys.net/~melanson/codecs/
 *
 * The MS RLE decoder outputs PAL8 colorspace data.
 *
 * Note that this decoder expects the palette colors from the end of the
 * BITMAPINFO header passed through palctrl.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "avcodec.h"
#include "dsputil.h"

typedef struct MsrleContext {
    AVCodecContext *avctx;
    AVFrame frame;

    unsigned char *buf;
    int size;

} MsrleContext;

#define FETCH_NEXT_STREAM_BYTE() \
    if (stream_ptr >= s->size) \
    { \
      av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
      return; \
    } \
    stream_byte = s->buf[stream_ptr++];

static void msrle_decode_pal4(MsrleContext *s)
{
    int stream_ptr = 0;
    unsigned char rle_code;
    unsigned char extra_byte, odd_pixel;
    unsigned char stream_byte;
    int pixel_ptr = 0;
    int row_dec = s->frame.linesize[0];
    int row_ptr = (s->avctx->height - 1) * row_dec;
    int frame_size = row_dec * s->avctx->height;
    int i;

    /* make the palette available */
    memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
    if (s->avctx->palctrl->palette_changed) {
        s->frame.palette_has_changed = 1;
        s->avctx->palctrl->palette_changed = 0;
    }

    while (row_ptr >= 0) {
        FETCH_NEXT_STREAM_BYTE();
        rle_code = stream_byte;
        if (rle_code == 0) {
            /* fetch the next byte to see how to handle escape code */
            FETCH_NEXT_STREAM_BYTE();
            if (stream_byte == 0) {
                /* line is done, goto the next one */
                row_ptr -= row_dec;
                pixel_ptr = 0;
            } else if (stream_byte == 1) {
                /* decode is done */
                return;
            } else if (stream_byte == 2) {
                /* reposition frame decode coordinates */
                FETCH_NEXT_STREAM_BYTE();
                pixel_ptr += stream_byte;
                FETCH_NEXT_STREAM_BYTE();
                row_ptr -= stream_byte * row_dec;
        } else {
            // copy pixels from encoded stream
            odd_pixel =  stream_byte & 1;
            rle_code = (stream_byte + 1) / 2;
            extra_byte = rle_code & 0x01;
            if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                (row_ptr < 0)) {
                av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
                return;
            }

            for (i = 0; i < rle_code; i++) {
                if (pixel_ptr >= s->avctx->width)
                    break;
                FETCH_NEXT_STREAM_BYTE();
                s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
                pixel_ptr++;
                if (i + 1 == rle_code && odd_pixel)
                    break;
                if (pixel_ptr >= s->avctx->width)
                    break;
                s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
                pixel_ptr++;
            }

            // if the RLE code is odd, skip a byte in the stream
            if (extra_byte)
              stream_ptr++;
            }
        } else {
            // decode a run of data
            if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                (row_ptr < 0)) {
                av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
                return;
            }
            FETCH_NEXT_STREAM_BYTE();
            for (i = 0; i < rle_code; i++) {
                if (pixel_ptr >= s->avctx->width)
                    break;
                if ((i & 1) == 0)
                    s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
                else
                    s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
                pixel_ptr++;
            }
        }
    }

    /* one last sanity check on the way out */
    if (stream_ptr < s->size)
        av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
            stream_ptr, s->size);
}



static void msrle_decode_pal8(MsrleContext *s)
{
    int stream_ptr = 0;
    unsigned char rle_code;
    unsigned char extra_byte;
    unsigned char stream_byte;
    int pixel_ptr = 0;
    int row_dec = s->frame.linesize[0];
    int row_ptr = (s->avctx->height - 1) * row_dec;
    int frame_size = row_dec * s->avctx->height;

    /* make the palette available */
    memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
    if (s->avctx->palctrl->palette_changed) {
        s->frame.palette_has_changed = 1;
        s->avctx->palctrl->palette_changed = 0;
    }

    while (row_ptr >= 0) {
        FETCH_NEXT_STREAM_BYTE();
        rle_code = stream_byte;
        if (rle_code == 0) {
            /* fetch the next byte to see how to handle escape code */
            FETCH_NEXT_STREAM_BYTE();
            if (stream_byte == 0) {
                /* line is done, goto the next one */
                row_ptr -= row_dec;
                pixel_ptr = 0;
            } else if (stream_byte == 1) {
                /* decode is done */
                return;
            } else if (stream_byte == 2) {
                /* reposition frame decode coordinates */
                FETCH_NEXT_STREAM_BYTE();
                pixel_ptr += stream_byte;
                FETCH_NEXT_STREAM_BYTE();
                row_ptr -= stream_byte * row_dec;
            } else {
                /* copy pixels from encoded stream */
                if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                    (row_ptr < 0)) {
                    av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
                    return;
                }

                rle_code = stream_byte;
                extra_byte = stream_byte & 0x01;
                if (stream_ptr + rle_code + extra_byte > s->size) {
                    av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (2)\n");
                    return;
                }

                while (rle_code--) {
                    FETCH_NEXT_STREAM_BYTE();
                    s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
                    pixel_ptr++;
                }

                /* if the RLE code is odd, skip a byte in the stream */
                if (extra_byte)
                    stream_ptr++;
            }
        } else {
            /* decode a run of data */
            if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                (row_ptr < 0)) {
                av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (2)\n");
                return;
            }

            FETCH_NEXT_STREAM_BYTE();

            while(rle_code--) {
                s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
                pixel_ptr++;
            }
        }
    }

    /* one last sanity check on the way out */
    if (stream_ptr < s->size)
        av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
            stream_ptr, s->size);
}

static int msrle_decode_init(AVCodecContext *avctx)
{
    MsrleContext *s = (MsrleContext *)avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = PIX_FMT_PAL8;
    avctx->has_b_frames = 0;
    s->frame.data[0] = NULL;

    return 0;
}

static int msrle_decode_frame(AVCodecContext *avctx,
                              void *data, int *data_size,
                              uint8_t *buf, int buf_size)
{
    MsrleContext *s = (MsrleContext *)avctx->priv_data;

    s->buf = buf;
    s->size = buf_size;

    s->frame.reference = 1;
    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    if (avctx->reget_buffer(avctx, &s->frame)) {
        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
        return -1;
    }

    switch (avctx->bits_per_sample) {
        case 8:
            msrle_decode_pal8(s);
            break;
        case 4:
            msrle_decode_pal4(s);
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n",
                   avctx->bits_per_sample);
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = s->frame;

    /* report that the buffer was completely consumed */
    return buf_size;
}

static int msrle_decode_end(AVCodecContext *avctx)
{
    MsrleContext *s = (MsrleContext *)avctx->priv_data;

    /* release the last frame */
    if (s->frame.data[0])
        avctx->release_buffer(avctx, &s->frame);

    return 0;
}

AVCodec msrle_decoder = {
    "msrle",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MSRLE,
    sizeof(MsrleContext),
    msrle_decode_init,
    NULL,
    msrle_decode_end,
    msrle_decode_frame,
    CODEC_CAP_DR1,
};