/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 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

*/

#include "SDL_config.h"

#include "SDL_stdinc.h"

#ifndef HAVE_GETENV

#if defined(__WIN32__) && !defined(_WIN32_WCE)

/* Note this isn't thread-safe! */

static char *SDL_envmem = NULL;	/* Ugh, memory leak */

static DWORD SDL_envmemlen = 0;

/* Put a variable of the form "name=value" into the environment */

int SDL_putenv(const char *variable)

{

	DWORD bufferlen;

	char *value;

	const char *sep;

	sep = SDL_strchr(variable, '=');

	if ( sep == NULL ) {

		return -1;

	}

	bufferlen = SDL_strlen(variable)+1;

	if ( bufferlen > SDL_envmemlen ) {

		char *newmem = (char *)SDL_realloc(SDL_envmem, bufferlen);

		if ( newmem == NULL ) {

			return -1;

		}

		SDL_envmem = newmem;

		SDL_envmemlen = bufferlen;

	}

	SDL_strlcpy(SDL_envmem, variable, bufferlen);

	value = SDL_envmem + (sep - variable);

	*value++ = '\0';

	if ( !SetEnvironmentVariable(SDL_envmem, *value ? value : NULL) ) {

		return -1;

	}

	return 0;

}

/* Retrieve a variable named "name" from the environment */

char *SDL_getenv(const char *name)

{

	DWORD bufferlen;

	bufferlen = GetEnvironmentVariable(name, SDL_envmem, SDL_envmemlen);

	if ( bufferlen == 0 ) {

		return NULL;

	}

	if ( bufferlen > SDL_envmemlen ) {

		char *newmem = (char *)SDL_realloc(SDL_envmem, bufferlen);

		if ( newmem == NULL ) {

			return NULL;

		}

		SDL_envmem = newmem;

		SDL_envmemlen = bufferlen;

		GetEnvironmentVariable(name, SDL_envmem, SDL_envmemlen);

	}

	return SDL_envmem;

}

#else /* roll our own */

static char **SDL_env = (char **)0;

/* Put a variable of the form "name=value" into the environment */

int SDL_putenv(const char *variable)

{

	const char *name, *value;

	int added;

	int len, i;

	char **new_env;

	char *new_variable;

	/* A little error checking */

	if ( ! variable ) {

		return(-1);

	}

	name = variable;

	for ( value=variable; *value && (*value != '='); ++value ) {

		/* Keep looking for '=' */ ;

	}

	if ( *value ) {

		++value;

	} else {

		return(-1);

	}

	/* Allocate memory for the variable */

	new_variable = SDL_strdup(variable);

	if ( ! new_variable ) {

		return(-1);

	}

	/* Actually put it into the environment */

	added = 0;

	i = 0;

	if ( SDL_env ) {

		/* Check to see if it's already there... */

		len = (value - name);

		for ( ; SDL_env[i]; ++i ) {

			if ( SDL_strncmp(SDL_env[i], name, len) == 0 ) {

				break;

			}

		}

		/* If we found it, just replace the entry */

		if ( SDL_env[i] ) {

			SDL_free(SDL_env[i]);

			SDL_env[i] = new_variable;

			added = 1;

		}

	}

	/* Didn't find it in the environment, expand and add */

	if ( ! added ) {

		new_env = SDL_realloc(SDL_env, (i+2)*sizeof(char *));

		if ( new_env ) {

			SDL_env = new_env;

			SDL_env[i++] = new_variable;

			SDL_env[i++] = (char *)0;

			added = 1;

		} else {

			SDL_free(new_variable);

		}

	}

	return (added ? 0 : -1);

}

/* Retrieve a variable named "name" from the environment */

char *SDL_getenv(const char *name)

{

	int len, i;

	char *value;

	value = (char *)0;

	if ( SDL_env ) {

		len = SDL_strlen(name);

		for ( i=0; SDL_env[i] && !value; ++i ) {

			if ( (SDL_strncmp(SDL_env[i], name, len) == 0) &&

			     (SDL_env[i][len] == '=') ) {

				value = &SDL_env[i][len+1];

			}

		}

	}

	return value;

}

#endif /* __WIN32__ */

#endif /* !HAVE_GETENV */

#ifdef TEST_MAIN

#include <stdio.h>

int main(int argc, char *argv[])

{

	char *value;

	printf("Checking for non-existent variable... ");

	fflush(stdout);

	if ( ! SDL_getenv("EXISTS") ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Setting FIRST=VALUE1 in the environment... ");

	fflush(stdout);

	if ( SDL_putenv("FIRST=VALUE1") == 0 ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Getting FIRST from the environment... ");

	fflush(stdout);

	value = SDL_getenv("FIRST");

	if ( value && (SDL_strcmp(value, "VALUE1") == 0) ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Setting SECOND=VALUE2 in the environment... ");

	fflush(stdout);

	if ( SDL_putenv("SECOND=VALUE2") == 0 ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Getting SECOND from the environment... ");

	fflush(stdout);

	value = SDL_getenv("SECOND");

	if ( value && (SDL_strcmp(value, "VALUE2") == 0) ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Setting FIRST=NOVALUE in the environment... ");

	fflush(stdout);

	if ( SDL_putenv("FIRST=NOVALUE") == 0 ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Getting FIRST from the environment... ");

	fflush(stdout);

	value = SDL_getenv("FIRST");

	if ( value && (SDL_strcmp(value, "NOVALUE") == 0) ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	printf("Checking for non-existent variable... ");

	fflush(stdout);

	if ( ! SDL_getenv("EXISTS") ) {

		printf("okay\n");

	} else {

		printf("failed\n");

	}

	return(0);

}

#endif /* TEST_MAIN */