IMG_xpm.c
author Sam Lantinga <slouken@libsdl.org>
Thu, 11 May 2006 18:46:23 +0000
changeset 139 e9827048fd14
parent 121 1bf9c0c87374
child 154 201cc5c1b373
permissions -rw-r--r--
Updated Visual C++ project
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/*
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    SDL_image:  An example image loading library for use with SDL
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    Copyright (C) 1997-2006 Sam Lantinga
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    This library is free software; you can redistribute it and/or
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    modify it under the terms of the GNU Lesser General Public
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    License as published by the Free Software Foundation; either
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    version 2.1 of the License, or (at your option) any later version.
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    This library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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    Lesser General Public License for more details.
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    You should have received a copy of the GNU Lesser General Public
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    License along with this library; if not, write to the Free Software
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    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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    Sam Lantinga
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    slouken@libsdl.org
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*/
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/*
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 * XPM (X PixMap) image loader:
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 *
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 * Supports the XPMv3 format, EXCEPT:
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 * - hotspot coordinates are ignored
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 * - only colour ('c') colour symbols are used
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 * - rgb.txt is not used (for portability), so only RGB colours
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 *   are recognized (#rrggbb etc) - only a few basic colour names are
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 *   handled
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 *
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 * The result is an 8bpp indexed surface if possible, otherwise 32bpp.
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 * The colourkey is correctly set if transparency is used.
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 * 
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 * Besides the standard API, also provides
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 *
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 *     SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
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 *
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 * that reads the image data from an XPM file included in the C source.
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 *
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 * TODO: include rgb.txt here. The full table (from solaris 2.6) only
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 * requires about 13K in binary form.
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 */
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include "SDL_image.h"
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#ifdef LOAD_XPM
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/* See if an image is contained in a data source */
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int IMG_isXPM(SDL_RWops *src)
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{
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	int start;
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	int is_XPM;
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	char magic[9];
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	start = SDL_RWtell(src);
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	is_XPM = 0;
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	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
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		if ( memcmp(magic, "/* XPM */", sizeof(magic)) == 0 ) {
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			is_XPM = 1;
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		}
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	}
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	SDL_RWseek(src, start, SEEK_SET);
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	return(is_XPM);
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}
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/* Hash table to look up colors from pixel strings */
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#define STARTING_HASH_SIZE 256
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struct hash_entry {
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	char *key;
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	Uint32 color;
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	struct hash_entry *next;
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};
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struct color_hash {
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	struct hash_entry **table;
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	struct hash_entry *entries; /* array of all entries */
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	struct hash_entry *next_free;
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	int size;
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	int maxnum;
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};
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static int hash_key(const char *key, int cpp, int size)
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{
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	int hash;
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	hash = 0;
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	while ( cpp-- > 0 ) {
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		hash = hash * 33 + *key++;
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	}
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	return hash & (size - 1);
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}
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static struct color_hash *create_colorhash(int maxnum)
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{
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	int bytes, s;
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	struct color_hash *hash;
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	/* we know how many entries we need, so we can allocate
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	   everything here */
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	hash = malloc(sizeof *hash);
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	if(!hash)
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		return NULL;
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	/* use power-of-2 sized hash table for decoding speed */
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	for(s = STARTING_HASH_SIZE; s < maxnum; s <<= 1)
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		;
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	hash->size = s;
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	hash->maxnum = maxnum;
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	bytes = hash->size * sizeof(struct hash_entry **);
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	hash->entries = NULL;	/* in case malloc fails */
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	hash->table = malloc(bytes);
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	if(!hash->table)
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		return NULL;
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	memset(hash->table, 0, bytes);
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	hash->entries = malloc(maxnum * sizeof(struct hash_entry));
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	if(!hash->entries)
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		return NULL;
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	hash->next_free = hash->entries;
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	return hash;
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}
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static int add_colorhash(struct color_hash *hash,
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                         char *key, int cpp, Uint32 color)
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{
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	int index = hash_key(key, cpp, hash->size);
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	struct hash_entry *e = hash->next_free++;
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	e->color = color;
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	e->key = key;
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	e->next = hash->table[index];
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	hash->table[index] = e;
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	return 1;
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}
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/* fast lookup that works if cpp == 1 */
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#define QUICK_COLORHASH(hash, key) ((hash)->table[*(Uint8 *)(key)]->color)
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static Uint32 get_colorhash(struct color_hash *hash, const char *key, int cpp)
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{
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	struct hash_entry *entry = hash->table[hash_key(key, cpp, hash->size)];
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	while(entry) {
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		if(memcmp(key, entry->key, cpp) == 0)
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			return entry->color;
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		entry = entry->next;
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	}
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	return 0;		/* garbage in - garbage out */
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}
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static void free_colorhash(struct color_hash *hash)
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{
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	if(hash && hash->table) {
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		free(hash->table);
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		free(hash->entries);
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		free(hash);
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	}
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}
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/* portable case-insensitive string comparison */
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static int string_equal(const char *a, const char *b, int n)
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{
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	while(*a && *b && n) {
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		if(toupper((unsigned char)*a) != toupper((unsigned char)*b))
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			return 0;
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		a++;
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		b++;
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		n--;
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	}
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	return *a == *b;
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}
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#define ARRAYSIZE(a) (int)(sizeof(a) / sizeof((a)[0]))
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/*
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 * convert colour spec to RGB (in 0xrrggbb format).
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 * return 1 if successful.
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 */
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static int color_to_rgb(char *spec, int speclen, Uint32 *rgb)
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{
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	/* poor man's rgb.txt */
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	static struct { char *name; Uint32 rgb; } known[] = {
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		{"none",  0xffffffff},
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		{"black", 0x00000000},
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		{"white", 0x00ffffff},
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		{"red",   0x00ff0000},
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		{"green", 0x0000ff00},
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		{"blue",  0x000000ff}
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	};
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	if(spec[0] == '#') {
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		char buf[7];
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		switch(speclen) {
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		case 4:
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			buf[0] = buf[1] = spec[1];
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			buf[2] = buf[3] = spec[2];
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			buf[4] = buf[5] = spec[3];
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			break;
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		case 7:
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			memcpy(buf, spec + 1, 6);
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			break;
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		case 13:
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			buf[0] = spec[1];
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			buf[1] = spec[2];
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			buf[2] = spec[5];
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			buf[3] = spec[6];
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			buf[4] = spec[9];
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			buf[5] = spec[10];
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			break;
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		}
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		buf[6] = '\0';
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		*rgb = strtol(buf, NULL, 16);
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		return 1;
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	} else {
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		int i;
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		for(i = 0; i < ARRAYSIZE(known); i++)
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			if(string_equal(known[i].name, spec, speclen)) {
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				*rgb = known[i].rgb;
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				return 1;
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			}
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		return 0;
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	}
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}
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#ifndef MAX
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#define MAX(a, b) ((a) > (b) ? (a) : (b))
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#endif
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static char *linebuf;
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static int buflen;
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static char *error;
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/*
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 * Read next line from the source.
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 * If len > 0, it's assumed to be at least len chars (for efficiency).
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 * Return NULL and set error upon EOF or parse error.
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 */
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static char *get_next_line(char ***lines, SDL_RWops *src, int len)
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{
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	if(lines) {
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		return *(*lines)++;
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	} else {
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		char c;
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		int n;
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		do {
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			if(SDL_RWread(src, &c, 1, 1) <= 0) {
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				error = "Premature end of data";
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				return NULL;
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			}
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		} while(c != '"');
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		if(len) {
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			len += 4;	/* "\",\n\0" */
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			if(len > buflen){
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				buflen = len;
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				linebuf = realloc(linebuf, buflen);
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				if(!linebuf) {
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					error = "Out of memory";
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					return NULL;
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				}
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			}
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			if(SDL_RWread(src, linebuf, len - 1, 1) <= 0) {
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				error = "Premature end of data";
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				return NULL;
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			}
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			n = len - 2;
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		} else {
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			n = 0;
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			do {
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				if(n >= buflen - 1) {
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					if(buflen == 0)
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						buflen = 16;
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					buflen *= 2;
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					linebuf = realloc(linebuf, buflen);
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					if(!linebuf) {
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						error = "Out of memory";
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						return NULL;
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					}
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				}
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				if(SDL_RWread(src, linebuf + n, 1, 1) <= 0) {
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					error = "Premature end of data";
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					return NULL;
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				}
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			} while(linebuf[n++] != '"');
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			n--;
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		}
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   291
		linebuf[n] = '\0';
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		return linebuf;
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	}
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}
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   296
#define SKIPSPACE(p)				\
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   297
do {						\
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   298
	while(isspace((unsigned char)*(p)))	\
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   299
	      ++(p);				\
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   300
} while(0)
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   301
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   302
#define SKIPNONSPACE(p)					\
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do {							\
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   304
	while(!isspace((unsigned char)*(p)) && *p)	\
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   305
	      ++(p);					\
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   306
} while(0)
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   307
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   308
/* read XPM from either array or RWops */
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static SDL_Surface *load_xpm(char **xpm, SDL_RWops *src)
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   310
{
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   311
	int start;
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   312
	SDL_Surface *image = NULL;
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   313
	int index;
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   314
	int x, y;
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   315
	int w, h, ncolors, cpp;
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   316
	int indexed;
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   317
	Uint8 *dst;
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   318
	struct color_hash *colors = NULL;
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   319
	SDL_Color *im_colors = NULL;
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   320
	char *keystrings = NULL, *nextkey;
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   321
	char *line;
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   322
	char ***xpmlines = NULL;
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   323
	int pixels_len;
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   324
slouken@38
   325
	error = NULL;
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   326
	linebuf = NULL;
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   327
	buflen = 0;
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   328
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   329
	start = SDL_RWtell(src);
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   330
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   331
	if(xpm)
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   332
		xpmlines = &xpm;
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   333
slouken@35
   334
	line = get_next_line(xpmlines, src, 0);
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   335
	if(!line)
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   336
		goto done;
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   337
	/*
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   338
	 * The header string of an XPMv3 image has the format
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   339
	 *
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   340
	 * <width> <height> <ncolors> <cpp> [ <hotspot_x> <hotspot_y> ]
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   341
	 *
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   342
	 * where the hotspot coords are intended for mouse cursors.
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   343
	 * Right now we don't use the hotspots but it should be handled
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   344
	 * one day.
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   345
	 */
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   346
	if(sscanf(line, "%d %d %d %d", &w, &h, &ncolors, &cpp) != 4
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   347
	   || w <= 0 || h <= 0 || ncolors <= 0 || cpp <= 0) {
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   348
		error = "Invalid format description";
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   349
		goto done;
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   350
	}
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   351
slouken@11
   352
	keystrings = malloc(ncolors * cpp);
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   353
	if(!keystrings) {
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   354
		error = "Out of memory";
slouken@35
   355
		goto done;
slouken@11
   356
	}
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   357
	nextkey = keystrings;
slouken@7
   358
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   359
	/* Create the new surface */
slouken@11
   360
	if(ncolors <= 256) {
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   361
		indexed = 1;
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   362
		image = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 8,
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   363
					     0, 0, 0, 0);
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   364
		im_colors = image->format->palette->colors;
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   365
		image->format->palette->ncolors = ncolors;
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   366
	} else {
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   367
		indexed = 0;
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   368
		image = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
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   369
					     0xff0000, 0x00ff00, 0x0000ff, 0);
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   370
	}
slouken@11
   371
	if(!image) {
slouken@11
   372
		/* Hmm, some SDL error (out of memory?) */
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   373
		goto done;
slouken@11
   374
	}
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   375
slouken@7
   376
	/* Read the colors */
slouken@11
   377
	colors = create_colorhash(ncolors);
slouken@35
   378
	if (!colors) {
slouken@11
   379
		error = "Out of memory";
slouken@11
   380
		goto done;
slouken@7
   381
	}
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   382
	for(index = 0; index < ncolors; ++index ) {
slouken@35
   383
		char *p;
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   384
		line = get_next_line(xpmlines, src, 0);
slouken@35
   385
		if(!line)
slouken@35
   386
			goto done;
slouken@11
   387
slouken@35
   388
		p = line + cpp + 1;
slouken@11
   389
slouken@11
   390
		/* parse a colour definition */
slouken@11
   391
		for(;;) {
slouken@11
   392
			char nametype;
slouken@11
   393
			char *colname;
slouken@35
   394
			Uint32 rgb, pixel;
slouken@11
   395
slouken@35
   396
			SKIPSPACE(p);
slouken@35
   397
			if(!*p) {
slouken@35
   398
				error = "colour parse error";
slouken@11
   399
				goto done;
slouken@7
   400
			}
slouken@35
   401
			nametype = *p;
slouken@35
   402
			SKIPNONSPACE(p);
slouken@35
   403
			SKIPSPACE(p);
slouken@35
   404
			colname = p;
slouken@35
   405
			SKIPNONSPACE(p);
slouken@11
   406
			if(nametype == 's')
slouken@11
   407
				continue;      /* skip symbolic colour names */
slouken@11
   408
slouken@35
   409
			if(!color_to_rgb(colname, p - colname, &rgb))
slouken@11
   410
				continue;
slouken@11
   411
slouken@35
   412
			memcpy(nextkey, line, cpp);
slouken@11
   413
			if(indexed) {
slouken@11
   414
				SDL_Color *c = im_colors + index;
slouken@139
   415
				c->r = (Uint8)(rgb >> 16);
slouken@139
   416
				c->g = (Uint8)(rgb >> 8);
slouken@139
   417
				c->b = (Uint8)(rgb);
slouken@35
   418
				pixel = index;
slouken@11
   419
			} else
slouken@35
   420
				pixel = rgb;
slouken@35
   421
			add_colorhash(colors, nextkey, cpp, pixel);
slouken@11
   422
			nextkey += cpp;
slouken@11
   423
			if(rgb == 0xffffffff)
slouken@35
   424
				SDL_SetColorKey(image, SDL_SRCCOLORKEY, pixel);
slouken@11
   425
			break;
slouken@7
   426
		}
slouken@7
   427
	}
slouken@7
   428
slouken@7
   429
	/* Read the pixels */
slouken@11
   430
	pixels_len = w * cpp;
slouken@11
   431
	dst = image->pixels;
slouken@35
   432
	for(y = 0; y < h; y++) {
slouken@35
   433
		line = get_next_line(xpmlines, src, pixels_len);
slouken@11
   434
		if(indexed) {
slouken@11
   435
			/* optimization for some common cases */
slouken@11
   436
			if(cpp == 1)
slouken@11
   437
				for(x = 0; x < w; x++)
slouken@139
   438
					dst[x] = (Uint8)QUICK_COLORHASH(colors,
slouken@35
   439
								 line + x);
slouken@11
   440
			else
slouken@11
   441
				for(x = 0; x < w; x++)
slouken@139
   442
					dst[x] = (Uint8)get_colorhash(colors,
slouken@35
   443
							       line + x * cpp,
slouken@11
   444
							       cpp);
slouken@11
   445
		} else {
slouken@11
   446
			for (x = 0; x < w; x++)
slouken@11
   447
				((Uint32*)dst)[x] = get_colorhash(colors,
slouken@35
   448
								line + x * cpp,
slouken@11
   449
								  cpp);
slouken@7
   450
		}
slouken@11
   451
		dst += image->pitch;
slouken@7
   452
	}
slouken@11
   453
slouken@11
   454
done:
slouken@11
   455
	if(error) {
slouken@118
   456
		SDL_RWseek(src, start, SEEK_SET);
slouken@118
   457
		if ( image ) {
slouken@118
   458
			SDL_FreeSurface(image);
slouken@118
   459
			image = NULL;
slouken@118
   460
		}
slouken@11
   461
		IMG_SetError(error);
slouken@7
   462
	}
slouken@11
   463
	free(keystrings);
slouken@7
   464
	free_colorhash(colors);
slouken@35
   465
	free(linebuf);
slouken@7
   466
	return(image);
slouken@7
   467
}
slouken@7
   468
slouken@35
   469
/* Load a XPM type image from an RWops datasource */
slouken@35
   470
SDL_Surface *IMG_LoadXPM_RW(SDL_RWops *src)
slouken@35
   471
{
slouken@98
   472
	if ( !src ) {
slouken@98
   473
		/* The error message has been set in SDL_RWFromFile */
slouken@98
   474
		return NULL;
slouken@98
   475
	}
slouken@35
   476
	return load_xpm(NULL, src);
slouken@35
   477
}
slouken@35
   478
slouken@35
   479
SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
slouken@35
   480
{
slouken@35
   481
	return load_xpm(xpm, NULL);
slouken@35
   482
}
slouken@35
   483
slouken@35
   484
#else  /* not LOAD_XPM */
slouken@7
   485
slouken@7
   486
/* See if an image is contained in a data source */
slouken@7
   487
int IMG_isXPM(SDL_RWops *src)
slouken@7
   488
{
slouken@7
   489
	return(0);
slouken@7
   490
}
slouken@7
   491
slouken@35
   492
slouken@7
   493
/* Load a XPM type image from an SDL datasource */
slouken@7
   494
SDL_Surface *IMG_LoadXPM_RW(SDL_RWops *src)
slouken@7
   495
{
slouken@7
   496
	return(NULL);
slouken@7
   497
}
slouken@7
   498
slouken@35
   499
SDL_Surface *IMG_ReadXPMFromArray(char **xpm)
slouken@35
   500
{
slouken@35
   501
    return NULL;
slouken@35
   502
}
slouken@35
   503
#endif /* not LOAD_XPM */