File: IMG_xpm.c

package info (click to toggle)
sdl-image1.2 1.2.12-12
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 6,936 kB
  • sloc: sh: 10,169; ansic: 9,638; objc: 248; csh: 219; makefile: 87
file content (533 lines) | stat: -rw-r--r-- 11,886 bytes parent folder | download
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
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
/*
  SDL_image:  An example image loading library for use with SDL
  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/*
 * XPM (X PixMap) image loader:
 *
 * Supports the XPMv3 format, EXCEPT:
 * - hotspot coordinates are ignored
 * - only colour ('c') colour symbols are used
 * - rgb.txt is not used (for portability), so only RGB colours
 *   are recognized (#rrggbb etc) - only a few basic colour names are
 *   handled
 *
 * The result is an 8bpp indexed surface if possible, otherwise 32bpp.
 * The colourkey is correctly set if transparency is used.
 * 
 * Besides the standard API, also provides
 *
 *     SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
 *
 * that reads the image data from an XPM file included in the C source.
 *
 * TODO: include rgb.txt here. The full table (from solaris 2.6) only
 * requires about 13K in binary form.
 */

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

#include "SDL_image.h"

#ifdef LOAD_XPM

/* See if an image is contained in a data source */
int IMG_isXPM(SDL_RWops *src)
{
	int start;
	int is_XPM;
	char magic[9];

	if ( !src )
		return 0;
	start = SDL_RWtell(src);
	is_XPM = 0;
	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
		if ( memcmp(magic, "/* XPM */", sizeof(magic)) == 0 ) {
			is_XPM = 1;
		}
	}
	SDL_RWseek(src, start, RW_SEEK_SET);
	return(is_XPM);
}

/* Hash table to look up colors from pixel strings */
#define STARTING_HASH_SIZE 256

struct hash_entry {
	char *key;
	Uint32 color;
	struct hash_entry *next;
};

struct color_hash {
	struct hash_entry **table;
	struct hash_entry *entries; /* array of all entries */
	struct hash_entry *next_free;
	int size;
	int maxnum;
};

static int hash_key(const char *key, int cpp, int size)
{
	int hash;

	hash = 0;
	while ( cpp-- > 0 ) {
		hash = hash * 33 + *key++;
	}
	return hash & (size - 1);
}

static struct color_hash *create_colorhash(int maxnum)
{
	int bytes, s;
	struct color_hash *hash;

	/* we know how many entries we need, so we can allocate
	   everything here */
	hash = calloc(1, sizeof *hash);
	if(!hash)
		return NULL;

	/* use power-of-2 sized hash table for decoding speed */
	for(s = STARTING_HASH_SIZE; s < maxnum; s <<= 1)
		;
	hash->size = s;
	hash->maxnum = maxnum;

	bytes = hash->size * sizeof(struct hash_entry **);
	/* Check for overflow */
	if ((bytes / sizeof(struct hash_entry **)) != hash->size) {
		IMG_SetError("memory allocation overflow");
		free(hash);
		return NULL;
	}
	hash->table = (struct hash_entry **)calloc(1, bytes);
	if(!hash->table)
		return NULL;

	bytes = maxnum * sizeof(struct hash_entry);
	/* Check for overflow */
	if ((bytes / sizeof(struct hash_entry)) != maxnum) {
		IMG_SetError("memory allocation overflow");
		free(hash->table);
		free(hash);
		return NULL;
	}
	hash->entries = (struct hash_entry *)calloc(1, bytes);
	if(!hash->entries) {
		free(hash->table);
		return NULL;
	}
	hash->next_free = hash->entries;
	return hash;
}

static int add_colorhash(struct color_hash *hash,
                         char *key, int cpp, Uint32 color)
{
	int index = hash_key(key, cpp, hash->size);
	struct hash_entry *e = hash->next_free++;
	e->color = color;
	e->key = key;
	e->next = hash->table[index];
	hash->table[index] = e;
	return 1;
}

/* fast lookup that works if cpp == 1 */
#define QUICK_COLORHASH(hash, key) ((hash)->table[*(Uint8 *)(key)]->color)

static Uint32 get_colorhash(struct color_hash *hash, const char *key, int cpp)
{
	struct hash_entry *entry = hash->table[hash_key(key, cpp, hash->size)];
	while(entry) {
		if(memcmp(key, entry->key, cpp) == 0)
			return entry->color;
		entry = entry->next;
	}
	return 0;		/* garbage in - garbage out */
}

static void free_colorhash(struct color_hash *hash)
{
	if(hash && hash->table) {
		free(hash->table);
		free(hash->entries);
		free(hash);
	}
}

/* portable case-insensitive string comparison */
static int string_equal(const char *a, const char *b, int n)
{
	while(*a && *b && n) {
		if(toupper((unsigned char)*a) != toupper((unsigned char)*b))
			return 0;
		a++;
		b++;
		n--;
	}
	return *a == *b;
}

#define ARRAYSIZE(a) (int)(sizeof(a) / sizeof((a)[0]))

/*
 * convert colour spec to RGB (in 0xrrggbb format).
 * return 1 if successful.
 */
static int color_to_rgb(char *spec, int speclen, Uint32 *rgb)
{
	/* poor man's rgb.txt */
	static struct { char *name; Uint32 rgb; } known[] = {
		{"none",  0xffffffff},
		{"black", 0x00000000},
		{"white", 0x00ffffff},
		{"red",   0x00ff0000},
		{"green", 0x0000ff00},
		{"blue",  0x000000ff}
	};

	if(spec[0] == '#') {
		char buf[7];
		switch(speclen) {
		case 4:
			buf[0] = buf[1] = spec[1];
			buf[2] = buf[3] = spec[2];
			buf[4] = buf[5] = spec[3];
			break;
		case 7:
			memcpy(buf, spec + 1, 6);
			break;
		case 13:
			buf[0] = spec[1];
			buf[1] = spec[2];
			buf[2] = spec[5];
			buf[3] = spec[6];
			buf[4] = spec[9];
			buf[5] = spec[10];
			break;
		}
		buf[6] = '\0';
		*rgb = strtol(buf, NULL, 16);
		return 1;
	} else {
		int i;
		for(i = 0; i < ARRAYSIZE(known); i++)
			if(string_equal(known[i].name, spec, speclen)) {
				*rgb = known[i].rgb;
				return 1;
			}
		return 0;
	}
}

#ifndef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif

static char *linebuf;
static int buflen;
static char *error;

/*
 * Read next line from the source.
 * If len > 0, it's assumed to be at least len chars (for efficiency).
 * Return NULL and set error upon EOF or parse error.
 */
static char *get_next_line(char ***lines, SDL_RWops *src, int len)
{
	char *linebufnew;

	if(lines) {
		return *(*lines)++;
	} else {
		char c;
		int n;
		do {
			if(SDL_RWread(src, &c, 1, 1) <= 0) {
				error = "Premature end of data";
				return NULL;
			}
		} while(c != '"');
		if(len) {
			len += 4;	/* "\",\n\0" */
			if(len > buflen){
				buflen = len;
				linebufnew = realloc(linebuf, buflen);
				if(!linebufnew) {
					free(linebuf);
					error = "Out of memory";
					return NULL;
				}
				linebuf = linebufnew;
			}
			if(SDL_RWread(src, linebuf, len - 1, 1) <= 0) {
				error = "Premature end of data";
				return NULL;
			}
			n = len - 2;
		} else {
			n = 0;
			do {
				if(n >= buflen - 1) {
					if(buflen == 0)
						buflen = 16;
					buflen *= 2;
					linebufnew = realloc(linebuf, buflen);
					if(!linebufnew) {
						free(linebuf);
						error = "Out of memory";
						return NULL;
					}
					linebuf = linebufnew;
				}
				if(SDL_RWread(src, linebuf + n, 1, 1) <= 0) {
					error = "Premature end of data";
					return NULL;
				}
			} while(linebuf[n++] != '"');
			n--;
		}
		linebuf[n] = '\0';
		return linebuf;
	}
}

#define SKIPSPACE(p)				\
do {						\
	while(isspace((unsigned char)*(p)))	\
	      ++(p);				\
} while(0)

#define SKIPNONSPACE(p)					\
do {							\
	while(!isspace((unsigned char)*(p)) && *p)	\
	      ++(p);					\
} while(0)

/* read XPM from either array or RWops */
static SDL_Surface *load_xpm(char **xpm, SDL_RWops *src)
{
	int start = 0;
	SDL_Surface *image = NULL;
	int index;
	int x, y;
	int w, h, ncolors, cpp;
	int indexed;
	Uint8 *dst;
	struct color_hash *colors = NULL;
	SDL_Color *im_colors = NULL;
	char *keystrings = NULL, *nextkey;
	char *line;
	char ***xpmlines = NULL;
	int pixels_len;

	error = NULL;
	linebuf = NULL;
	buflen = 0;

	if ( src ) 
		start = SDL_RWtell(src);

	if(xpm)
		xpmlines = &xpm;

	line = get_next_line(xpmlines, src, 0);
	if(!line)
		goto done;
	/*
	 * The header string of an XPMv3 image has the format
	 *
	 * <width> <height> <ncolors> <cpp> [ <hotspot_x> <hotspot_y> ]
	 *
	 * where the hotspot coords are intended for mouse cursors.
	 * Right now we don't use the hotspots but it should be handled
	 * one day.
	 */
	if(sscanf(line, "%d %d %d %d", &w, &h, &ncolors, &cpp) != 4
	   || w <= 0 || h <= 0 || ncolors <= 0 || cpp <= 0) {
		error = "Invalid format description";
		goto done;
	}

	/* Check for allocation overflow */
	if ((size_t)(ncolors * cpp)/cpp != ncolors) {
		error = "Invalid color specification";
		goto done;
	}
	keystrings = malloc(ncolors * cpp);
	if(!keystrings) {
		error = "Out of memory";
		goto done;
	}
	nextkey = keystrings;

	/* Create the new surface */
	if(ncolors <= 256) {
		indexed = 1;
		image = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 8,
					     0, 0, 0, 0);
		im_colors = image->format->palette->colors;
		image->format->palette->ncolors = ncolors;
	} else {
		indexed = 0;
		image = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
					     0xff0000, 0x00ff00, 0x0000ff, 0);
	}
	if(!image) {
		/* Hmm, some SDL error (out of memory?) */
		goto done;
	}

	/* Read the colors */
	colors = create_colorhash(ncolors);
	if (!colors) {
		error = "Out of memory";
		goto done;
	}
	for(index = 0; index < ncolors; ++index ) {
		char *p;
		line = get_next_line(xpmlines, src, 0);
		if(!line)
			goto done;

		p = line + cpp + 1;

		/* parse a colour definition */
		for(;;) {
			char nametype;
			char *colname;
			Uint32 rgb, pixel;

			SKIPSPACE(p);
			if(!*p) {
				error = "colour parse error";
				goto done;
			}
			nametype = *p;
			SKIPNONSPACE(p);
			SKIPSPACE(p);
			colname = p;
			SKIPNONSPACE(p);
			if(nametype == 's')
				continue;      /* skip symbolic colour names */

			if(!color_to_rgb(colname, p - colname, &rgb))
				continue;

			memcpy(nextkey, line, cpp);
			if(indexed) {
				SDL_Color *c = im_colors + index;
				c->r = (Uint8)(rgb >> 16);
				c->g = (Uint8)(rgb >> 8);
				c->b = (Uint8)(rgb);
				pixel = index;
			} else
				pixel = rgb;
			add_colorhash(colors, nextkey, cpp, pixel);
			nextkey += cpp;
			if(rgb == 0xffffffff)
				SDL_SetColorKey(image, SDL_SRCCOLORKEY, pixel);
			break;
		}
	}

	/* Read the pixels */
	pixels_len = w * cpp;
	dst = image->pixels;
	for(y = 0; y < h; y++) {
		line = get_next_line(xpmlines, src, pixels_len);
		if(indexed) {
			/* optimization for some common cases */
			if(cpp == 1)
				for(x = 0; x < w; x++)
					dst[x] = (Uint8)QUICK_COLORHASH(colors,
								 line + x);
			else
				for(x = 0; x < w; x++)
					dst[x] = (Uint8)get_colorhash(colors,
							       line + x * cpp,
							       cpp);
		} else {
			for (x = 0; x < w; x++)
				((Uint32*)dst)[x] = get_colorhash(colors,
								line + x * cpp,
								  cpp);
		}
		dst += image->pitch;
	}

done:
	if(error) {
		if ( src )
			SDL_RWseek(src, start, RW_SEEK_SET);
		if ( image ) {
			SDL_FreeSurface(image);
			image = NULL;
		}
		IMG_SetError(error);
	}
	free(keystrings);
	free_colorhash(colors);
	free(linebuf);
	return(image);
}

/* Load a XPM type image from an RWops datasource */
SDL_Surface *IMG_LoadXPM_RW(SDL_RWops *src)
{
	if ( !src ) {
		/* The error message has been set in SDL_RWFromFile */
		return NULL;
	}
	return load_xpm(NULL, src);
}

SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
{
	return load_xpm(xpm, NULL);
}

#else  /* not LOAD_XPM */

/* See if an image is contained in a data source */
int IMG_isXPM(SDL_RWops *src)
{
	return(0);
}


/* Load a XPM type image from an SDL datasource */
SDL_Surface *IMG_LoadXPM_RW(SDL_RWops *src)
{
	return(NULL);
}

SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
{
    return NULL;
}
#endif /* not LOAD_XPM */