/*

    SDL_image:  An example image loading library for use with SDL

    Copyright (C) 1997-2009 Sam Lantinga

    This library 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.

    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

    Lesser General Public License for more details.

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

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

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

/* A simple library to load images of various formats as SDL surfaces */

#include <stdio.h>

#include <string.h>

#include <ctype.h>

#include "SDL_image.h"

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

/* Table of image detection and loading functions */

static struct {

	char *type;

	int (SDLCALL *is)(SDL_RWops *src);

	SDL_Surface *(SDLCALL *load)(SDL_RWops *src);

} supported[] = {

	/* keep magicless formats first */

	{ "PNG", IMG_isPNG, IMG_LoadPNG_RW }

};

extern int IMG_InitPNG();

extern void IMG_QuitPNG();

static int initialized = 0;

int IMG_Init(int flags)

{

	int result = 0;

	if (flags & IMG_INIT_PNG) {

		if ((initialized & IMG_INIT_PNG) || IMG_InitPNG() == 0) {

			result |= IMG_INIT_PNG;

		}

	}

	initialized |= result;

	return (result);

}

void IMG_Quit()

{

	if (initialized & IMG_INIT_PNG) {

		IMG_QuitPNG();

	}

	initialized = 0;

}

/* Load an image from a file */

SDL_Surface *IMG_Load(const char *file)

{

    SDL_RWops *src = SDL_RWFromFile(file, "rb");

    char *ext = strrchr(file, '.');

    if(ext) {

        ext++;

    }

    if(!src) {

        /* The error message has been set in SDL_RWFromFile */

        return NULL;

    }

    return IMG_LoadTyped_RW(src, 1, ext);

}

/* Load an image from an SDL datasource (for compatibility) */

SDL_Surface *IMG_Load_RW(SDL_RWops *src, int freesrc)

{

    return IMG_LoadTyped_RW(src, freesrc, NULL);

}

/* Portable case-insensitive string compare function */

static int IMG_string_equals(const char *str1, const char *str2)

{

	while ( *str1 && *str2 ) {

		if ( toupper((unsigned char)*str1) !=

		     toupper((unsigned char)*str2) )

			break;

		++str1;

		++str2;

	}

	return (!*str1 && !*str2);

}

/* Load an image from an SDL datasource, optionally specifying the type */

SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)

{

	int i;

	SDL_Surface *image;

	/* Make sure there is something to do.. */

	if ( src == NULL ) {

		IMG_SetError("Passed a NULL data source");

		return(NULL);

	}

	/* See whether or not this data source can handle seeking */

	if ( SDL_RWseek(src, 0, RW_SEEK_CUR) < 0 ) {

		IMG_SetError("Can't seek in this data source");

		if(freesrc)

			SDL_RWclose(src);

		return(NULL);

	}

	/* Detect the type of image being loaded */

	image = NULL;

	for ( i=0; i < ARRAYSIZE(supported); ++i ) {

		if(supported[i].is) {

			if(!supported[i].is(src))

				continue;

		} else {

			/* magicless format */

			if(!type

			   || !IMG_string_equals(type, supported[i].type))

				continue;

		}

#ifdef DEBUG_IMGLIB

		fprintf(stderr, "IMGLIB: Loading image as %s\n", supported[i].type);

#endif

		image = supported[i].load(src);

		if(freesrc)

			SDL_RWclose(src);

		return image;

	}

	if ( freesrc ) {

		SDL_RWclose(src);

	}

	IMG_SetError("Unsupported image format");

	return NULL;

}