SDL_image: An example image loading library for use with SDL

Copyright (C) 1999, 2000, 2001 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

*/

/* $Id$ */

/*

* 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 <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)

{

return (SDL_RWread(src, magic, sizeof(magic), 1)

&& memcmp(magic, "/* XPM */", 9) == 0);

}

/* 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 hash_entry **table;

struct hash_entry *entries; /* array of all entries */

struct hash_entry *next_free;

int size;

int maxnum;

};

{

int hash;

hash = 0;

while ( cpp-- > 0 ) {

}

struct color_hash *hash;

/* we know how many entries we need, so we can allocate

everything here */

hash = malloc(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 **);

hash->entries = NULL; /* in case malloc fails */

hash->table = malloc(bytes);

if(!hash->table)

return NULL;

memset(hash->table, 0, bytes);

hash->entries = malloc(maxnum * sizeof(struct hash_entry));

if(!hash->entries)

return NULL;

hash->next_free = hash->entries;

return hash;

}

static int add_colorhash(struct color_hash *hash,

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;

}

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;

}

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;

}

/*

* convert colour spec to RGB (in 0xrrggbb format).

{

/* 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];

case 7:

memcpy(buf, spec + 1, 6);

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];

}

buf[6] = '\0';

*rgb = strtol(buf, NULL, 16);

return 1;

} else {

int i;

for(i = 0; i < ARRAYSIZE(known); i++)

*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.

*/

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;

linebuf = realloc(linebuf, buflen);

if(!linebuf) {

error = "Out of memory";

return NULL;

}

}

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;

linebuf = realloc(linebuf, buflen);

if(!linebuf) {

error = "Out of memory";

return NULL;

}

}

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 w, h, ncolors, cpp;

int indexed;

Uint8 *dst;

char *keystrings = NULL, *nextkey;

char *line;

char ***xpmlines = NULL;

int pixels_len;

error = NULL;

linebuf = NULL;

buflen = 0;

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.

*/

error = "Invalid format description";

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?) */

/* Read the colors */

error = "Out of memory";

goto done;

char *p;

line = get_next_line(xpmlines, src, 0);

if(!line)

goto done;

/* parse a colour definition */

for(;;) {

char nametype;

char *colname;

Uint32 rgb, pixel;

SKIPSPACE(p);

if(!*p) {

error = "colour parse error";

nametype = *p;

SKIPNONSPACE(p);

SKIPSPACE(p);

colname = p;

SKIPNONSPACE(p);

if(nametype == 's')

continue; /* skip symbolic colour names */

continue;

if(indexed) {

SDL_Color *c = im_colors + index;

c->r = rgb >> 16;

c->g = rgb >> 8;

c->b = rgb;

pixel = rgb;

add_colorhash(colors, nextkey, cpp, pixel);

nextkey += cpp;

if(rgb == 0xffffffff)

}

}

/* 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] = QUICK_COLORHASH(colors,

else

for(x = 0; x < w; x++)

dst[x] = get_colorhash(colors,

cpp);

} else {

for (x = 0; x < w; x++)

((Uint32*)dst)[x] = get_colorhash(colors,

cpp);

}

dst += image->pitch;

image = NULL;

IMG_SetError(error);

}

free(keystrings);

return(image);

}

/* Load a XPM type image from an RWops datasource */

SDL_Surface *IMG_LoadXPM_RW(SDL_RWops *src)

{

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 */