aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/sgi.c
blob: 5adcb3791e650449fdb78a70688ad483c023e915 (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
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
/*
 * SGI image format
 * Todd Kirby <doubleshot@pacbell.net>
 *
 * 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 "avformat.h"
#include "avio.h"

/* #define DEBUG */

/* sgi image file signature */
#define SGI_MAGIC 474

#define SGI_HEADER_SIZE 512

#define SGI_GRAYSCALE 1
#define SGI_RGB 3
#define SGI_RGBA 4

#define SGI_SINGLE_CHAN 2
#define SGI_MULTI_CHAN 3

typedef struct SGIInfo{
    short magic;
    char rle;
    char bytes_per_channel;
    unsigned short dimension;
    unsigned short xsize;
    unsigned short ysize;
    unsigned short zsize;
} SGIInfo;


static int sgi_probe(AVProbeData *pd)
{
    /* test for sgi magic */
    if (pd->buf_size >= 2 && AV_RB16(&pd->buf[0]) == SGI_MAGIC) {
        return AVPROBE_SCORE_MAX;
    } else {
        return 0;
    }
}

/* read sgi header fields */
static void read_sgi_header(ByteIOContext *f, SGIInfo *info)
{
    info->magic = (unsigned short) get_be16(f);
    info->rle = get_byte(f);
    info->bytes_per_channel = get_byte(f);
    info->dimension = (unsigned short)get_be16(f);
    info->xsize = (unsigned short) get_be16(f);
    info->ysize = (unsigned short) get_be16(f);
    info->zsize = (unsigned short) get_be16(f);

    if(info->zsize > 4096)
        info->zsize= 0;

#ifdef DEBUG
    printf("sgi header fields:\n");
    printf("  magic: %d\n", info->magic);
    printf("    rle: %d\n", info->rle);
    printf("    bpc: %d\n", info->bytes_per_channel);
    printf("    dim: %d\n", info->dimension);
    printf("  xsize: %d\n", info->xsize);
    printf("  ysize: %d\n", info->ysize);
    printf("  zsize: %d\n", info->zsize);
#endif

    return;
}


/* read an uncompressed sgi image */
static int read_uncompressed_sgi(const SGIInfo *si,
        AVPicture *pict, ByteIOContext *f)
{
    int x, y, z, chan_offset, ret = 0;
    uint8_t *dest_row;

    /* skip header */
    url_fseek(f, SGI_HEADER_SIZE, SEEK_SET);

    pict->linesize[0] = si->xsize;

    for (z = 0; z < si->zsize; z++) {

#ifndef WORDS_BIGENDIAN
        /* rgba -> bgra for rgba32 on little endian cpus */
        if (si->zsize == 4 && z != 3)
            chan_offset = 2 - z;
        else
#endif
            chan_offset = z;

        for (y = si->ysize - 1; y >= 0; y--) {
            dest_row = pict->data[0] + (y * si->xsize * si->zsize);

            for (x = 0; x < si->xsize; x++) {
                dest_row[chan_offset] = get_byte(f);
                dest_row += si->zsize;
            }
        }
    }

    return ret;
}


/* expand an rle row into a channel */
static int expand_rle_row(ByteIOContext *f, unsigned char *optr,
        int chan_offset, int pixelstride)
{
    unsigned char pixel, count;
    int length = 0;

#ifndef WORDS_BIGENDIAN
    /* rgba -> bgra for rgba32 on little endian cpus */
    if (pixelstride == 4 && chan_offset != 3) {
       chan_offset = 2 - chan_offset;
    }
#endif

    optr += chan_offset;

    while (1) {
        pixel = get_byte(f);

        if (!(count = (pixel & 0x7f))) {
            return length;
        }
        if (pixel & 0x80) {
            while (count--) {
                *optr = get_byte(f);
                length++;
                optr += pixelstride;
            }
        } else {
            pixel = get_byte(f);

            while (count--) {
                *optr = pixel;
                length++;
                optr += pixelstride;
            }
        }
    }
}


/* read a run length encoded sgi image */
static int read_rle_sgi(const SGIInfo *sgi_info,
        AVPicture *pict, ByteIOContext *f)
{
    uint8_t *dest_row;
    unsigned long *start_table;
    int y, z, xsize, ysize, zsize, tablen;
    long start_offset;
    int ret = 0;

    xsize = sgi_info->xsize;
    ysize = sgi_info->ysize;
    zsize = sgi_info->zsize;

    /* skip header */
    url_fseek(f, SGI_HEADER_SIZE, SEEK_SET);

    /* size of rle offset and length tables */
    tablen = ysize * zsize * sizeof(long);

    start_table = (unsigned long *)av_malloc(tablen);

    if (!get_buffer(f, (uint8_t *)start_table, tablen)) {
        ret = AVERROR_IO;
        goto fail;
    }

    /* skip run length table */
    url_fseek(f, tablen, SEEK_CUR);

    for (z = 0; z < zsize; z++) {
        for (y = 0; y < ysize; y++) {
            dest_row = pict->data[0] + (ysize - 1 - y) * (xsize * zsize);

            start_offset = AV_RB32(&start_table[y + z * ysize]);

            /* don't seek if already at the next rle start offset */
            if (url_ftell(f) != start_offset) {
                url_fseek(f, start_offset, SEEK_SET);
            }

            if (expand_rle_row(f, dest_row, z, zsize) != xsize) {
              ret =  AVERROR_INVALIDDATA;
              goto fail;
            }
        }
    }

fail:
    av_free(start_table);

    return ret;
}


static int sgi_read(ByteIOContext *f,
        int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
{
    SGIInfo sgi_info, *s = &sgi_info;
    AVImageInfo info1, *info = &info1;
    int ret;

    read_sgi_header(f, s);

    if (s->bytes_per_channel != 1) {
        return AVERROR_INVALIDDATA;
    }

    /* check for supported image dimensions */
    if (s->dimension != 2 && s->dimension != 3) {
        return AVERROR_INVALIDDATA;
    }

    if (s->zsize == SGI_GRAYSCALE) {
        info->pix_fmt = PIX_FMT_GRAY8;
    } else if (s->zsize == SGI_RGB) {
        info->pix_fmt = PIX_FMT_RGB24;
    } else if (s->zsize == SGI_RGBA) {
        info->pix_fmt = PIX_FMT_RGBA32;
    } else {
        return AVERROR_INVALIDDATA;
    }

    info->width = s->xsize;
    info->height = s->ysize;

    ret = alloc_cb(opaque, info);
    if (ret)
        return ret;

    if (s->rle) {
        return read_rle_sgi(s, &info->pict, f);
    } else {
        return read_uncompressed_sgi(s, &info->pict, f);
    }

    return 0; /* not reached */
}

#ifdef CONFIG_MUXERS
static void write_sgi_header(ByteIOContext *f, const SGIInfo *info)
{
    int i;

    put_be16(f, SGI_MAGIC);
    put_byte(f, info->rle);
    put_byte(f, info->bytes_per_channel);
    put_be16(f, info->dimension);
    put_be16(f, info->xsize);
    put_be16(f, info->ysize);
    put_be16(f, info->zsize);

    /* The rest are constant in this implementation */
    put_be32(f, 0L); /* pixmin */
    put_be32(f, 255L); /* pixmax */
    put_be32(f, 0L); /* dummy */

    /* name */
    for (i = 0; i < 80; i++) {
        put_byte(f, 0);
    }

    put_be32(f, 0L); /* colormap */

    /* The rest of the 512 byte header is unused. */
    for (i = 0; i < 404; i++) {
        put_byte(f, 0);
    }
}


static int rle_row(ByteIOContext *f, char *row, int stride, int rowsize)
{
    int length, count, i, x;
    char *start, repeat = 0;

    for (x = rowsize, length = 0; x > 0;) {
        start = row;
        row += (2 * stride);
        x -= 2;

        while (x > 0 && (row[-2 * stride] != row[-1 * stride] ||
                    row[-1 * stride] != row[0])) {
            row += stride;
            x--;
        };

        row -= (2 * stride);
        x += 2;

        count = (row - start) / stride;
        while (count > 0) {
            i = count > 126 ? 126 : count;
            count -= i;

            put_byte(f, 0x80 | i);
            length++;

            while (i > 0) {
                put_byte(f, *start);
                start += stride;
                i--;
                length++;
            };
        };

        if (x <= 0) {
            break;
        }

        start = row;
        repeat = row[0];

        row += stride;
        x--;

        while (x > 0 && *row == repeat) {
            row += stride;
            x--;
        };

        count = (row - start) / stride;
        while (count > 0) {
            i = count > 126 ? 126 : count;
            count -= i;

            put_byte(f, i);
            length++;

            put_byte(f, repeat);
            length++;
        };
    };

    length++;

    put_byte(f, 0);
    return (length);
}


static int sgi_write(ByteIOContext *pb, AVImageInfo *info)
{
    SGIInfo sgi_info, *si = &sgi_info;
    long *offsettab, *lengthtab;
    int i, y, z;
    int tablesize, chan_offset;
    uint8_t *srcrow;

    si->xsize = info->width;
    si->ysize = info->height;
    si->rle = 1;
    si->bytes_per_channel = 1;

    switch(info->pix_fmt) {
        case PIX_FMT_GRAY8:
            si->dimension = SGI_SINGLE_CHAN;
            si->zsize = SGI_GRAYSCALE;
            break;
        case PIX_FMT_RGB24:
            si->dimension = SGI_MULTI_CHAN;
            si->zsize = SGI_RGB;
            break;
         case PIX_FMT_RGBA32:
            si->dimension = SGI_MULTI_CHAN;
            si->zsize = SGI_RGBA;
            break;
        default:
            return AVERROR_INVALIDDATA;
    }

    write_sgi_header(pb, si);

    tablesize = si->zsize * si->ysize * sizeof(long);

    /* skip rle offset and length tables, write them at the end. */
    url_fseek(pb, tablesize * 2, SEEK_CUR);
    put_flush_packet(pb);

    lengthtab = av_malloc(tablesize);
    offsettab = av_malloc(tablesize);

    for (z = 0; z < si->zsize; z++) {

#ifndef WORDS_BIGENDIAN
        /* rgba -> bgra for rgba32 on little endian cpus */
        if (si->zsize == 4 && z != 3)
            chan_offset = 2 - z;
        else
#endif
            chan_offset = z;

        srcrow = info->pict.data[0] + chan_offset;

        for (y = si->ysize -1; y >= 0; y--) {
            offsettab[(z * si->ysize) + y] = url_ftell(pb);
            lengthtab[(z * si->ysize) + y] = rle_row(pb, srcrow,
                    si->zsize, si->xsize);
            srcrow += info->pict.linesize[0];
        }
    }

    url_fseek(pb, 512, SEEK_SET);

    /* write offset table */
    for (i = 0; i < (si->ysize * si->zsize); i++) {
        put_be32(pb, offsettab[i]);
    }

    /* write length table */
    for (i = 0; i < (si->ysize * si->zsize); i++) {
        put_be32(pb, lengthtab[i]);
    }

    put_flush_packet(pb);

    av_free(lengthtab);
    av_free(offsettab);

    return 0;
}
#endif // CONFIG_MUXERS

AVImageFormat sgi_image_format = {
    "sgi",
    "sgi,rgb,rgba,bw",
    sgi_probe,
    sgi_read,
    (1 << PIX_FMT_GRAY8) | (1 << PIX_FMT_RGB24) | (1 << PIX_FMT_RGBA32),
#ifdef CONFIG_MUXERS
    sgi_write,
#else
    NULL,
#endif // CONFIG_MUXERS
};