summaryrefslogtreecommitdiff
path: root/image/bmpread.c
blob: 15c103ae091d89abfac97aec2e29877fed20d91a (plain)
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
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
/*
 * This file is part of NetSurf, http://netsurf.sourceforge.net/
 * Licensed under the GNU General Public License,
 *		  http://www.opensource.org/licenses/gpl-license
 * Copyright 2006 Richard Wilson <info@tinct.net>
 */


#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "netsurf/image/bmpread.h"
#include "netsurf/image/bitmap.h"
#include "netsurf/utils/log.h"

#define READ_SHORT(a, o) (a[o]|(a[o+1]<<8))
#define READ_INT(a, o) (a[o]|(a[o+1]<<8)|(a[o+2]<<16)|(a[o+3]<<24))

bmp_result bmp_decode_rgb24(struct bmp_image *bmp, char *data, int bytes);
bmp_result bmp_decode_rgb(struct bmp_image *bmp, char *data, int bytes);
bmp_result bmp_decode_rle(struct bmp_image *bmp, char *data, int bytes, int size);


/**
 * Analyse a BMP prior to decoding.
 *
 * This function will scan the data provided and perform simple checks to
 * ensure the data is a valid BMP.
 *
 * This function must be called before bmp_decode() and sets up all the
 * relevant values in the bmp structure.
 *
 * \param bmp	the BMP image to analyse
 * \return BMP_OK on success
 */
bmp_result bmp_analyse(struct bmp_image *bmp) {
	char *data = bmp->bmp_data;
	unsigned int header_size;
	unsigned int i;
	int width, height;
	int palette_size;

	/* ensure we aren't already initialised */
	if (bmp->bitmap)
		return BMP_OK;

	/* standard 14-byte BMP file header is:
	 *
	 *	+0	SHORT	'BM'
	 *	+2	INT	size of file (in bytes)
	 *	+6	SHORT	reserved field (1)
	 *	+8	SHORT	reserved field (2)
	 *	+10	INT	starting position of image data (in bytes)
	 */
	if (bmp->buffer_size < 14)
		return BMP_INSUFFICIENT_DATA;
	if ((data[0] != 'B') || (data[1] != 'M'))
		return BMP_DATA_ERROR;
	bmp->bitmap_offset = READ_INT(data, 10);
	data += 14;

	/* a variety of different bitmap headers can now follow, depending
	 * on the BMP variant. A full description of the various headers
	 * can be found at http://www.fileformat.info/format/bmp/
	 */
	header_size = READ_INT(data, 0);
	if (bmp->buffer_size < (14 + header_size))
		return BMP_INSUFFICIENT_DATA;
	if (header_size == 12) {
		/* the following header is for os/2 and windows 2.x and consists of:
		 *
		 *	+0	INT	size of this header (in bytes)
		 *	+4	SHORT	image�width�(in�pixels)
		 *	+6	SHORT	image�height�(in�pixels)
		 *	+8	SHORT	number�of�color�planes�(always 1)
		 *	+10	SHORT	number�of�bits�per�pixel
		 */
		width = READ_SHORT(data, 4);
		height = READ_SHORT(data, 6);
		if (width < 0)
			return BMP_DATA_ERROR;
		if (height < 0) {
		  	bmp->reversed = true;
		  	height = -height;
		}
		bmp->width = width;
		bmp->height = height;
		if (READ_SHORT(data, 8) != 1)
			return BMP_DATA_ERROR;
		bmp->bpp = READ_SHORT(data, 10);
		bmp->colours = (1 << bmp->bpp);
		palette_size = 3;
	} else if (header_size < 40) {
		return BMP_DATA_ERROR;
	} else {
	  	/* the following header is for windows 3.x and onwards. it is a
	  	 * minimum of 40 bytes and (as of Windows 95) a maximum of 108 bytes.
		 *
		 *	+0	INT	size�of�this�header�(in�bytes)
		 *	+4	INT	image�width�(in�pixels)
		 *	+8	INT	image height�(in�pixels)
�		 *	+12	SHORT	number�of�color�planes�(always 1)
		 *	+14	SHORT	number�of�bits�per�pixel
		 *	+16	INT	compression�methods�used
		 *	+20	INT	size�of�bitmap�(in�bytes)
		 *	+24	INT	horizontal�resolution�(in�pixels�per�meter)
		 *	+28	INT	vertical�resolution�(in�pixels�per�meter)
		 *	+32	INT	number�of�colors�in�the�image
		 *	+36	INT	number�of�important�colors
		 *	+40	INT	mask�identifying�bits�of�red�component
		 *	+44	INT	mask�identifying�bits�of�green�component
		 *	+48	INT	mask�identifying�bits�of�blue�component
		 *	+52	INT	mask�identifying�bits�of�alpha�component
		 *	+56	INT	color�space�type
		 *	+60	INT	x�coordinate�of�red�endpoint
		 *	+64	INT	y�coordinate�of�red�endpoint
		 *	+68	INT	z�coordinate�of�red�endpoint
		 *	+72	INT	x�coordinate�of�green�endpoint
		 *	+76	INT	y�coordinate�of�green�endpoint
		 *	+80	INT	z�coordinate�of�green�endpoint
		 *	+84	INT	x�coordinate�of�blue�endpoint
		 *	+88	INT	y�coordinate�of�blue�endpoint
		 *	+92	INT	z�coordinate�of�blue�endpoint
		 *	+96	INT	gamma�red�coordinate�scale�value
		 *	+100	INT	gamma�green�coordinate�scale�value
		 *	+104	INT	gamma�blue�coordinate�scale�value
		 */
		width = READ_INT(data, 4);
		height = READ_INT(data, 8);
		if (width < 0)
			return BMP_DATA_ERROR;
		if (height < 0) {
		  	bmp->reversed = true;
		  	height = -height;
		}
		bmp->width = width;
		bmp->height = height;
		if (READ_SHORT(data, 12) != 1)
			return BMP_DATA_ERROR;
		bmp->bpp = READ_SHORT(data, 14);
		bmp->encoding = READ_INT(data, 16);
		if (bmp->encoding >= BMP_ENCODING_BITFIELDS)	/* unsupported so far */
			return BMP_DATA_ERROR;
		bmp->colours = READ_INT(data, 32);
		if (bmp->colours == 0)
			bmp->colours = (1 << bmp->bpp);
		palette_size = 4;
		/* we don't understand the rest of the data yet */
	}
	data += header_size;

	/* we only have a palette for <16bpp */
	if (bmp->bpp < 16) {
		/* we now have a series of palette entries of the format:
		 *
		 *	+0	BYTE	blue
		 *	+1	BYTE	green
		 *	+2	BYTE	red
		 *
		 * if the palette is from an OS/2 or Win2.x file then the entries
		 * are padded with an extra byte. 
		 */
		if (bmp->buffer_size < (14 + header_size + (4 * bmp->colours)))
			return BMP_INSUFFICIENT_DATA;
		bmp->colour_table = (unsigned int *)
				malloc(bmp->colours * sizeof(int));
		if (!bmp->colour_table)
			return BMP_INSUFFICIENT_MEMORY;
		for (i = 0; i < bmp->colours; i++) {
			bmp->colour_table[i] = (data[2] | (data[1] << 8) |
					(data[0] << 16) | (0xff << 24));
			data += palette_size;
		}
	}

	/* create our bitmap */
	bmp->bitmap = bitmap_create(bmp->width, bmp->height,
			BITMAP_NEW | BITMAP_OPAQUE | BITMAP_CLEAR_MEMORY);
	if (!bmp->bitmap) {
		if (bmp->colour_table)
			free(bmp->colour_table);
		bmp->colour_table = NULL;
		return BMP_INSUFFICIENT_MEMORY;
	}
	return BMP_OK;
}


/**
 * Decode a BMP
 *
 * This function decodes the BMP data such that bmp->bitmap is a valid
 * image. The state of bmp->decoded is set to TRUE on exit such that it
 * can easily be identified which BMPs are in a fully decoded state.
 *
 * \param bmp	the BMP image to decode
 * \return BMP_OK on success
 */
bmp_result bmp_decode(struct bmp_image *bmp) {
	char *data;
	int bytes;

	assert(bmp->bitmap);

	data = bmp->bmp_data + bmp->bitmap_offset;
	bytes = bmp->buffer_size - bmp->bitmap_offset;

	switch (bmp->encoding) {
		case BMP_ENCODING_RGB:
			if (bmp->bpp >= 24)
				return bmp_decode_rgb24(bmp, data, bytes);
			else if (bmp->bpp > 8)
				return BMP_DATA_ERROR;
			else
				return bmp_decode_rgb(bmp, data, bytes);
		case BMP_ENCODING_RLE8:
			return bmp_decode_rle(bmp, data, bytes, 8);
		case BMP_ENCODING_RLE4:
			return bmp_decode_rle(bmp, data, bytes, 4);
		case BMP_ENCODING_BITFIELDS:
			/* todo: implement me */
			break;
	}
	return BMP_DATA_ERROR;
}


/**
 * Decode BMP data stored in 24bpp colour.
 *
 * \param bmp	the BMP image to decode
 * \param data	the data to decode
 * \param bytes	the number of bytes of data available
 * \return BMP_OK on success
 */
bmp_result bmp_decode_rgb24(struct bmp_image *bmp, char *data, int bytes) {
	char *top, *bottom, *end;
	unsigned int *scanline;
	unsigned int x, y, swidth, skip;
	unsigned int addr;

	swidth = bitmap_get_rowstride(bmp->bitmap);
	top = bitmap_get_buffer(bmp->bitmap);
	bottom = top + swidth * (bmp->height - 1);
	end = data + bytes;
	addr = ((unsigned int)data) & 3;
	skip = bmp->bpp >> 3;
	bmp->decoded = true;

	for (y = 0; y < bmp->height; y++) {
		while (addr != (((unsigned int)data) & 3))
			data++;
		if ((data + (skip * bmp->width)) > end)
			return BMP_INSUFFICIENT_DATA;
		if (bmp->reversed)
			scanline = (unsigned int *)(top + (y * swidth));
		else
			scanline = (unsigned int *)(bottom - (y * swidth));
		for (x = 0; x < bmp->width; x++) {
			scanline[x] = data[2] | (data[1] << 8) | (data[0] << 16);
			data += skip;
		}
	}
	return BMP_OK;
}


/**
 * Decode BMP data stored with a palette and in 8bpp colour or less.
 *
 * \param bmp	the BMP image to decode
 * \param data	the data to decode
 * \param bytes	the number of bytes of data available
 * \return BMP_OK on success
 */
bmp_result bmp_decode_rgb(struct bmp_image *bmp, char *data, int bytes) {
	char *top, *bottom, *end;
	unsigned int *scanline;
	unsigned int addr;
	unsigned int x, y, swidth;
	int i;
	int bit_shifts[8];
	int ppb = 8 / bmp->bpp;
	int bit_mask = (1 << bmp->bpp) - 1;
	int cur_byte = 0, bit;

	for (i = 0; i < ppb; i++)
	    bit_shifts[i] = 8 - ((i + 1) * bmp->bpp);

	swidth = bitmap_get_rowstride(bmp->bitmap);
	top = bitmap_get_buffer(bmp->bitmap);
	bottom = top + swidth * (bmp->height - 1);
	end = data + bytes;
	addr = ((unsigned int)data) & 3;
	bmp->decoded = true;

	for (y = 0; y < bmp->height; y++) {
		while (addr != (((unsigned int)data) & 3))
			data++;
		bit = 32;
		if ((data + (bmp->width / ppb)) > end)
			return BMP_INSUFFICIENT_DATA;
		if (bmp->reversed)
			scanline = (unsigned int *)(top + (y * swidth));
		else
			scanline = (unsigned int *)(bottom - (y * swidth));
		for (x = 0; x < bmp->width; x++) {
			if (bit >= ppb) {
				bit = 0;
				cur_byte = *data++;
			}
			scanline[x] = bmp->colour_table[(cur_byte >>
					bit_shifts[bit++]) & bit_mask];
		}
	}
	return BMP_OK;
}


/**
 * Decode BMP data stored encoded in either RLE4 or RLE8.
 *
 * \param bmp	the BMP image to decode
 * \param data	the data to decode
 * \param bytes	the number of bytes of data available
 * \param size	the size of the RLE tokens (4 or 8)
 * \return BMP_OK on success
 */
bmp_result bmp_decode_rle(struct bmp_image *bmp, char *data, int bytes, int size) {
	char *top, *bottom, *end;
	unsigned int *scanline;
	unsigned int swidth;
	int i, length, pixels_left;
	unsigned int x = 0, y = 0, last_y = 0;
	unsigned int pixel = 0, pixel2;

	swidth = bitmap_get_rowstride(bmp->bitmap);
	top = bitmap_get_buffer(bmp->bitmap);
	bottom = top + swidth * (bmp->height - 1);
	end = data + bytes;
	bmp->decoded = true;
	
	do {
	  	if (data + 2 > end)
	  		return BMP_INSUFFICIENT_DATA;
		length = *data++;
		if (length == 0) {
			length = *data++;
			if (length == 0) {
			  	/* 00 - 00 means end of scanline */
				x = 0;
				if (last_y == y) {
					if (++y > bmp->height)
						return BMP_DATA_ERROR;
				}
				last_y = y;
			} else if (length == 1) {
			  	/* 00 - 01 means end of RLE data */
				return BMP_OK;
			} else if (length == 2) {
			  	/* 00 - 02 - XX - YY means move cursor */
			  	if (data + 2 > end)
			  		return BMP_INSUFFICIENT_DATA;
				x += *data++;
				if (x >= bmp->width)
					return BMP_DATA_ERROR;
				y += *data++;
				if (y >= bmp->height)
					return BMP_DATA_ERROR;
			} else {
				/* 00 - NN means escape pixels */
				if (bmp->reversed) {
					pixels_left = (y + 1) * bmp->width - x;
					scanline = (unsigned int *)(top + (y * swidth));
				} else {
					pixels_left = (bmp->height - y + 1) * bmp->width - x;
					scanline = (unsigned int *)(bottom - (y * swidth));
				}
			  	if (length > pixels_left)
			  		length = pixels_left;
			  	if (data + length > end)
	  				return BMP_INSUFFICIENT_DATA;

			  	/* the following code could be easily optimised by simply
			  	 * checking the bounds on entry and using some simply copying
			  	 * routines if so */
				if (size == 8) {
					for (i = 0; i < length; i++) {
						if (x >= bmp->width) {
							x = 0;
							if (++y > bmp->height)
								return BMP_DATA_ERROR;
							scanline -= bmp->width;
						}
						scanline[x++] = bmp->colour_table[(int)*data++];
					}
				} else {
					for (i = 0; i < length; i++) {
						if (x >= bmp->width) {
							x = 0;
							if (++y > bmp->height)
								return BMP_DATA_ERROR;
							scanline -= bmp->width;
						}
					  	if ((i & 1) == 0) {
							pixel = *data++;
							scanline[x++] = bmp->colour_table
									[pixel >> 4];
						} else {				  
							scanline[x++] = bmp->colour_table
									[pixel & 0xf];
						}
					}
					length = (length + 1) >> 1;
				}
				if ((length & 1) && (*data++ != 0x00))
					return BMP_DATA_ERROR;

			}
		} else {
		  	/* NN means perform RLE for NN pixels */ 
			if (bmp->reversed) {
				pixels_left = (y + 1) * bmp->width - x;
				scanline = (unsigned int *)(top + (y * swidth));
			} else {
				pixels_left = (bmp->height - y + 1) * bmp->width - x;
				scanline = (unsigned int *)(bottom - (y * swidth));
			}
		  	if (length > pixels_left)
		  		length = pixels_left;

		  	/* the following code could be easily optimised by simply
		  	 * checking the bounds on entry and using some simply copying
		  	 * routines if so */
			if (size == 8) {
				pixel = bmp->colour_table[(int)*data++];
				for (i = 0; i < length; i++) {
					if (x >= bmp->width) {
						x = 0;
						if (++y > bmp->height)
							return BMP_DATA_ERROR;
						scanline -= bmp->width;
					}
					scanline[x++] = pixel;
				}
			} else {
				pixel2 = *data++;
				pixel = bmp->colour_table[pixel2 >> 4];
				pixel2 = bmp->colour_table[pixel2 & 0xf];
				for (i = 0; i < length; i++) {
					if (x >= bmp->width) {
						x = 0;
						if (++y > bmp->height)
							return BMP_DATA_ERROR;
						scanline -= bmp->width;
					}
					if ((i & 1) == 0)
						scanline[x++] = pixel;
					else
						scanline[x++] = pixel2;
				}
			}
		}
	} while (data < end);
	return BMP_OK;
}


/**
 * Finalise a BMP prior to destruction.
 *
 * \param bmp	the BMP image to finalise
 */
void bmp_finalise(struct bmp_image *bmp) {
	if (bmp->bitmap)
		bitmap_destroy(bmp->bitmap);
	bmp->bitmap = NULL;
	if (bmp->colour_table)
		free(bmp->colour_table);
	bmp->colour_table = NULL;
}