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                            const uint8_t *buf, int buf_size)
39{
40    BMPContext *s = avctx->priv_data;
41    AVFrame *picture = data;
42    AVFrame *p = &s->picture;
43    unsigned int fsize, hsize;
44    int width, height;
45    unsigned int depth;
46    BiCompression comp;
47    unsigned int ihsize;
48    int i, j, n, linesize;
49    uint32_t rgb[3];
50    uint8_t *ptr;
51    int dsize;
52    const uint8_t *buf0 = buf;
53
54    if(buf_size < 14){
55        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
56        return -1;
57    }
58
59    if(bytestream_get_byte(&buf) != 'B' ||
60       bytestream_get_byte(&buf) != 'M') {
61        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
62        return -1;
63    }
64
65    fsize = bytestream_get_le32(&buf);
66    if(buf_size < fsize){
67        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d), trying to decode anyway\n",
68               buf_size, fsize);
69        fsize = buf_size;
70    }
71
72    buf += 2; /* reserved1 */
73    buf += 2; /* reserved2 */
74
75    hsize = bytestream_get_le32(&buf); /* header size */
76    ihsize = bytestream_get_le32(&buf);       /* more header size */
77    if(ihsize + 14 > hsize){
78        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
79        return -1;
80    }
81
82    /* sometimes file size is set to some headers size, set a real size in that case */
83    if(fsize == 14 || fsize == ihsize + 14)
84        fsize = buf_size - 2;
85
86    if(fsize <= hsize){
87        av_log(avctx, AV_LOG_ERROR, "declared file size is less than header size (%d < %d)\n",
88               fsize, hsize);
89        return -1;
90    }
91
92    switch(ihsize){
93    case  40: // windib v3
94    case  64: // OS/2 v2
95    case 108: // windib v4
96    case 124: // windib v5
97        width = bytestream_get_le32(&buf);
98        height = bytestream_get_le32(&buf);
99        break;
100    case  12: // OS/2 v1
101        width  = bytestream_get_le16(&buf);
102        height = bytestream_get_le16(&buf);
103        break;
104    default:
105        av_log(avctx, AV_LOG_ERROR, "unsupported BMP file, patch welcome\n");
106        return -1;
107    }
108
109    if(bytestream_get_le16(&buf) != 1){ /* planes */
110        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
111        return -1;
112    }
113
114    depth = bytestream_get_le16(&buf);
115
116    if(ihsize == 40)
117        comp = bytestream_get_le32(&buf);
118    else
119        comp = BMP_RGB;
120
121    if(comp != BMP_RGB && comp != BMP_BITFIELDS && comp != BMP_RLE4 && comp != BMP_RLE8){
122        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
123        return -1;
124    }
125
126    if(comp == BMP_BITFIELDS){
127        buf += 20;
128        rgb[0] = bytestream_get_le32(&buf);
129        rgb[1] = bytestream_get_le32(&buf);
130        rgb[2] = bytestream_get_le32(&buf);
131    }
132
133    avctx->width = width;
134    avctx->height = height > 0? height: -height;
135
136    avctx->pix_fmt = PIX_FMT_NONE;
137
138    switch(depth){
139    case 32:
140        if(comp == BMP_BITFIELDS){
141            rgb[0] = (rgb[0] >> 15) & 3;
142            rgb[1] = (rgb[1] >> 15) & 3;
143            rgb[2] = (rgb[2] >> 15) & 3;
144
145            if(rgb[0] + rgb[1] + rgb[2] != 3 ||
146               rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
147                break;
148            }
149        } else {
150            rgb[0] = 2;
151            rgb[1] = 1;
152            rgb[2] = 0;
153        }
154
155        avctx->pix_fmt = PIX_FMT_BGR24;
156        break;
157    case 24:
158        avctx->pix_fmt = PIX_FMT_BGR24;
159        break;
160    case 16:
161        if(comp == BMP_RGB)
162            avctx->pix_fmt = PIX_FMT_RGB555;
163        if(comp == BMP_BITFIELDS)
164            avctx->pix_fmt = rgb[1] == 0x07E0 ? PIX_FMT_RGB565 : PIX_FMT_RGB555;
165        break;
166    case 8:
167        if(hsize - ihsize - 14 > 0)
168            avctx->pix_fmt = PIX_FMT_PAL8;
169        else
170            avctx->pix_fmt = PIX_FMT_GRAY8;
171        break;
172    case 4:
173        if(hsize - ihsize - 14 > 0){
174            avctx->pix_fmt = PIX_FMT_PAL8;
175        }else{
176            av_log(avctx, AV_LOG_ERROR, "Unknown palette for 16-colour BMP\n");
177            return -1;
178        }
179        break;
180    case 1:
181        avctx->pix_fmt = PIX_FMT_MONOBLACK;
182        break;
183    default:
184        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
185        return -1;
186    }
187
188    if(avctx->pix_fmt == PIX_FMT_NONE){
189        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
190        return -1;
191    }
192
193    if(p->data[0])
194        avctx->release_buffer(avctx, p);
195
196    p->reference = 0;
197    if(avctx->get_buffer(avctx, p) < 0){
198        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
199        return -1;
200    }
201    p->pict_type = FF_I_TYPE;
202    p->key_frame = 1;
203
204    buf = buf0 + hsize;
205    dsize = buf_size - hsize;
206
207    /* Line size in file multiple of 4 */
208    n = ((avctx->width * depth) / 8 + 3) & ~3;
209
210    if(n * avctx->height > dsize && comp != BMP_RLE4 && comp != BMP_RLE8){
211        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
212               dsize, n * avctx->height);
213        return -1;
214    }
215
216    // RLE may skip decoding some picture areas, so blank picture before decoding
217    if(comp == BMP_RLE4 || comp == BMP_RLE8)
218        memset(p->data[0], 0, avctx->height * p->linesize[0]);
219
220    if(depth == 4 || depth == 8)
221        memset(p->data[1], 0, 1024);
222
223    if(height > 0){
224        ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
225        linesize = -p->linesize[0];
226    } else {
227        ptr = p->data[0];
228        linesize = p->linesize[0];
229    }
230
231    if(avctx->pix_fmt == PIX_FMT_PAL8){
232        buf = buf0 + 14 + ihsize; //palette location
233        if((hsize-ihsize-14)>>depth < 4){ // OS/2 bitmap, 3 bytes per palette entry
234            for(i = 0; i < (1 << depth); i++)
235                ((uint32_t*)p->data[1])[i] = bytestream_get_le24(&buf);
236        }else{
237            for(i = 0; i < (1 << depth); i++)
238                ((uint32_t*)p->data[1])[i] = bytestream_get_le32(&buf);
239        }
240        buf = buf0 + hsize;
241    }
242    if(comp == BMP_RLE4 || comp == BMP_RLE8){
243        ff_msrle_decode(avctx, (AVPicture*)p, depth, buf, dsize);
244    }else{
245        switch(depth){
246        case 1:
247            for(i = 0; i < avctx->height; i++){
248                memcpy(ptr, buf, n);
249                buf += n;
250                ptr += linesize;
251            }
252            break;
253        case 4:
254            for(i = 0; i < avctx->height; i++){
255                int j;
256                for(j = 0; j < n; j++){
257                    ptr[j*2+0] = (buf[j] >> 4) & 0xF;
258                    ptr[j*2+1] = buf[j] & 0xF;
259                }
260                buf += n;
261                ptr += linesize;
262            }
263            break;
264        case 8:
265            for(i = 0; i < avctx->height; i++){
266                memcpy(ptr, buf, avctx->width);
267                buf += n;
268                ptr += linesize;
269            }
270            break;
271        case 24:
272            for(i = 0; i < avctx->height; i++){
273                memcpy(ptr, buf, avctx->width*(depth>>3));
274                buf += n;
275                ptr += linesize;
276            }
277            break;
278        case 16:
279            for(i = 0; i < avctx->height; i++){
280                const uint16_t *src = (const uint16_t *) buf;
281                uint16_t *dst = (uint16_t *) ptr;
282
283                for(j = 0; j < avctx->width; j++)
284                    *dst++ = le2me_16(*src++);
285
286                buf += n;
287                ptr += linesize;
288            }
289            break;
290        case 32:
291            for(i = 0; i < avctx->height; i++){
292                const uint8_t *src = buf;
293                uint8_t *dst = ptr;
294
295                for(j = 0; j < avctx->width; j++){
296                    dst[0] = src[rgb[2]];
297                    dst[1] = src[rgb[1]];
298                    dst[2] = src[rgb[0]];
299                    dst += 3;
300                    src += 4;
301                }
302
303                buf += n;
304                ptr += linesize;
305            }
306            break;
307        default:
308            av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
309            return -1;
310        }
311    }
312
313    *picture = s->picture;
314    *data_size = sizeof(AVPicture);
315
316    return buf_size;
317}
318
319static av_cold int bmp_decode_end(AVCodecContext *avctx)
320{
321    BMPContext* c = avctx->priv_data;
322
323    if (c->picture.data[0])
324        avctx->release_buffer(avctx, &c->picture);
325
326    return 0;
327}
328
329AVCodec bmp_decoder = {
330    "bmp",
331    CODEC_TYPE_VIDEO,
332    CODEC_ID_BMP,
333    sizeof(BMPContext),
334    bmp_decode_init,
335    NULL,
336    bmp_decode_end,
337    bmp_decode_frame,
338    .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
339};
340