1/*
2 * BMP image format decoder
3 * Copyright (c) 2005 Mans Rullgard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "avcodec.h"
23#include "bytestream.h"
24#include "bmp.h"
25#include "msrledec.h"
26
27static av_cold int bmp_decode_init(AVCodecContext *avctx){
28    BMPContext *s = avctx->priv_data;
29
30    avcodec_get_frame_defaults((AVFrame*)&s->picture);
31    avctx->coded_frame = (AVFrame*)&s->picture;
32
33    return 0;
34}
35
36static int bmp_decode_frame(AVCodecContext *avctx,
37                            void *data, int *data_size,
38                            AVPacket *avpkt)
39{
40    const uint8_t *buf = avpkt->data;
41    int buf_size = avpkt->size;
42    BMPContext *s = avctx->priv_data;
43    AVFrame *picture = data;
44    AVFrame *p = &s->picture;
45    unsigned int fsize, hsize;
46    int width, height;
47    unsigned int depth;
48    BiCompression comp;
49    unsigned int ihsize;
50    int i, j, n, linesize;
51    uint32_t rgb[3];
52    uint8_t *ptr;
53    int dsize;
54    const uint8_t *buf0 = buf;
55
56    if(buf_size < 14){
57        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
58        return -1;
59    }
60
61    if(bytestream_get_byte(&buf) != 'B' ||
62       bytestream_get_byte(&buf) != 'M') {
63        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
64        return -1;
65    }
66
67    fsize = bytestream_get_le32(&buf);
68    if(buf_size < fsize){
69        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d), trying to decode anyway\n",
70               buf_size, fsize);
71        fsize = buf_size;
72    }
73
74    buf += 2; /* reserved1 */
75    buf += 2; /* reserved2 */
76
77    hsize = bytestream_get_le32(&buf); /* header size */
78    ihsize = bytestream_get_le32(&buf);       /* more header size */
79    if(ihsize + 14 > hsize){
80        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
81        return -1;
82    }
83
84    /* sometimes file size is set to some headers size, set a real size in that case */
85    if(fsize == 14 || fsize == ihsize + 14)
86        fsize = buf_size - 2;
87
88    if(fsize <= hsize){
89        av_log(avctx, AV_LOG_ERROR, "declared file size is less than header size (%d < %d)\n",
90               fsize, hsize);
91        return -1;
92    }
93
94    switch(ihsize){
95    case  40: // windib v3
96    case  64: // OS/2 v2
97    case 108: // windib v4
98    case 124: // windib v5
99        width = bytestream_get_le32(&buf);
100        height = bytestream_get_le32(&buf);
101        break;
102    case  12: // OS/2 v1
103        width  = bytestream_get_le16(&buf);
104        height = bytestream_get_le16(&buf);
105        break;
106    default:
107        av_log(avctx, AV_LOG_ERROR, "unsupported BMP file, patch welcome\n");
108        return -1;
109    }
110
111    if(bytestream_get_le16(&buf) != 1){ /* planes */
112        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
113        return -1;
114    }
115
116    depth = bytestream_get_le16(&buf);
117
118    if(ihsize == 40)
119        comp = bytestream_get_le32(&buf);
120    else
121        comp = BMP_RGB;
122
123    if(comp != BMP_RGB && comp != BMP_BITFIELDS && comp != BMP_RLE4 && comp != BMP_RLE8){
124        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
125        return -1;
126    }
127
128    if(comp == BMP_BITFIELDS){
129        buf += 20;
130        rgb[0] = bytestream_get_le32(&buf);
131        rgb[1] = bytestream_get_le32(&buf);
132        rgb[2] = bytestream_get_le32(&buf);
133    }
134
135    avctx->width = width;
136    avctx->height = height > 0? height: -height;
137
138    avctx->pix_fmt = PIX_FMT_NONE;
139
140    switch(depth){
141    case 32:
142        if(comp == BMP_BITFIELDS){
143            rgb[0] = (rgb[0] >> 15) & 3;
144            rgb[1] = (rgb[1] >> 15) & 3;
145            rgb[2] = (rgb[2] >> 15) & 3;
146
147            if(rgb[0] + rgb[1] + rgb[2] != 3 ||
148               rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
149                break;
150            }
151        } else {
152            rgb[0] = 2;
153            rgb[1] = 1;
154            rgb[2] = 0;
155        }
156
157        avctx->pix_fmt = PIX_FMT_BGR24;
158        break;
159    case 24:
160        avctx->pix_fmt = PIX_FMT_BGR24;
161        break;
162    case 16:
163        if(comp == BMP_RGB)
164            avctx->pix_fmt = PIX_FMT_RGB555;
165        if(comp == BMP_BITFIELDS)
166            avctx->pix_fmt = rgb[1] == 0x07E0 ? PIX_FMT_RGB565 : PIX_FMT_RGB555;
167        break;
168    case 8:
169        if(hsize - ihsize - 14 > 0)
170            avctx->pix_fmt = PIX_FMT_PAL8;
171        else
172            avctx->pix_fmt = PIX_FMT_GRAY8;
173        break;
174    case 4:
175        if(hsize - ihsize - 14 > 0){
176            avctx->pix_fmt = PIX_FMT_PAL8;
177        }else{
178            av_log(avctx, AV_LOG_ERROR, "Unknown palette for 16-colour BMP\n");
179            return -1;
180        }
181        break;
182    case 1:
183        avctx->pix_fmt = PIX_FMT_MONOBLACK;
184        break;
185    default:
186        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
187        return -1;
188    }
189
190    if(avctx->pix_fmt == PIX_FMT_NONE){
191        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
192        return -1;
193    }
194
195    if(p->data[0])
196        avctx->release_buffer(avctx, p);
197
198    p->reference = 0;
199    if(avctx->get_buffer(avctx, p) < 0){
200        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
201        return -1;
202    }
203    p->pict_type = FF_I_TYPE;
204    p->key_frame = 1;
205
206    buf = buf0 + hsize;
207    dsize = buf_size - hsize;
208
209    /* Line size in file multiple of 4 */
210    n = ((avctx->width * depth) / 8 + 3) & ~3;
211
212    if(n * avctx->height > dsize && comp != BMP_RLE4 && comp != BMP_RLE8){
213        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
214               dsize, n * avctx->height);
215        return -1;
216    }
217
218    // RLE may skip decoding some picture areas, so blank picture before decoding
219    if(comp == BMP_RLE4 || comp == BMP_RLE8)
220        memset(p->data[0], 0, avctx->height * p->linesize[0]);
221
222    if(depth == 4 || depth == 8)
223        memset(p->data[1], 0, 1024);
224
225    if(height > 0){
226        ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
227        linesize = -p->linesize[0];
228    } else {
229        ptr = p->data[0];
230        linesize = p->linesize[0];
231    }
232
233    if(avctx->pix_fmt == PIX_FMT_PAL8){
234        int colors = 1 << depth;
235        if(ihsize >= 36){
236            int t;
237            buf = buf0 + 46;
238            t = bytestream_get_le32(&buf);
239            if(t < 0 || t > (1 << depth)){
240                av_log(avctx, AV_LOG_ERROR, "Incorrect number of colors - %X for bitdepth %d\n", t, depth);
241            }else if(t){
242                colors = t;
243            }
244        }
245        buf = buf0 + 14 + ihsize; //palette location
246        if((hsize-ihsize-14) < (colors << 2)){ // OS/2 bitmap, 3 bytes per palette entry
247            for(i = 0; i < colors; i++)
248                ((uint32_t*)p->data[1])[i] = bytestream_get_le24(&buf);
249        }else{
250            for(i = 0; i < colors; i++)
251                ((uint32_t*)p->data[1])[i] = bytestream_get_le32(&buf);
252        }
253        buf = buf0 + hsize;
254    }
255    if(comp == BMP_RLE4 || comp == BMP_RLE8){
256        if(height < 0){
257            p->data[0] += p->linesize[0] * (avctx->height - 1);
258            p->linesize[0] = -p->linesize[0];
259        }
260        ff_msrle_decode(avctx, (AVPicture*)p, depth, buf, dsize);
261        if(height < 0){
262            p->data[0] += p->linesize[0] * (avctx->height - 1);
263            p->linesize[0] = -p->linesize[0];
264        }
265    }else{
266        switch(depth){
267        case 1:
268        case 8:
269        case 24:
270            for(i = 0; i < avctx->height; i++){
271                memcpy(ptr, buf, n);
272                buf += n;
273                ptr += linesize;
274            }
275            break;
276        case 4:
277            for(i = 0; i < avctx->height; i++){
278                int j;
279                for(j = 0; j < n; j++){
280                    ptr[j*2+0] = (buf[j] >> 4) & 0xF;
281                    ptr[j*2+1] = buf[j] & 0xF;
282                }
283                buf += n;
284                ptr += linesize;
285            }
286            break;
287        case 16:
288            for(i = 0; i < avctx->height; i++){
289                const uint16_t *src = (const uint16_t *) buf;
290                uint16_t *dst = (uint16_t *) ptr;
291
292                for(j = 0; j < avctx->width; j++)
293                    *dst++ = le2me_16(*src++);
294
295                buf += n;
296                ptr += linesize;
297            }
298            break;
299        case 32:
300            for(i = 0; i < avctx->height; i++){
301                const uint8_t *src = buf;
302                uint8_t *dst = ptr;
303
304                for(j = 0; j < avctx->width; j++){
305                    dst[0] = src[rgb[2]];
306                    dst[1] = src[rgb[1]];
307                    dst[2] = src[rgb[0]];
308                    dst += 3;
309                    src += 4;
310                }
311
312                buf += n;
313                ptr += linesize;
314            }
315            break;
316        default:
317            av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
318            return -1;
319        }
320    }
321
322    *picture = s->picture;
323    *data_size = sizeof(AVPicture);
324
325    return buf_size;
326}
327
328static av_cold int bmp_decode_end(AVCodecContext *avctx)
329{
330    BMPContext* c = avctx->priv_data;
331
332    if (c->picture.data[0])
333        avctx->release_buffer(avctx, &c->picture);
334
335    return 0;
336}
337
338AVCodec bmp_decoder = {
339    "bmp",
340    AVMEDIA_TYPE_VIDEO,
341    CODEC_ID_BMP,
342    sizeof(BMPContext),
343    bmp_decode_init,
344    NULL,
345    bmp_decode_end,
346    bmp_decode_frame,
347    CODEC_CAP_DR1,
348    .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
349};
350