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SDL_getenv.c
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/* Not all environments have a working getenv()/putenv() */
#ifdef TEST_MAIN
#define NEED_SDL_GETENV
#endif
#include "SDL_getenv.h"
#ifdef NEED_SDL_GETENV
#include <stdlib.h>
#include <string.h>
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 = (char *)malloc(strlen(variable)+1);
if ( ! new_variable ) {
return(-1);
}
strcpy(new_variable, variable);
/* 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 ( strncmp(SDL_env[i], name, len) == 0 ) {
break;
}
}
/* If we found it, just replace the entry */
if ( SDL_env[i] ) {
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 = 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 {
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 = strlen(name);
for ( i=0; SDL_env[i] && !value; ++i ) {
if ( (strncmp(SDL_env[i], name, len) == 0) &&
(SDL_env[i][len] == '=') ) {
value = &SDL_env[i][len+1];
}
}
}
return value;
}
#endif /* NEED_GETENV */
#ifdef TEST_MAIN
#include <stdio.h>
int main(int argc, char *argv[])
{
char *value;
printf("Checking for non-existent variable... ");
fflush(stdout);
if ( ! getenv("EXISTS") ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Setting FIRST=VALUE1 in the environment... ");
fflush(stdout);
if ( putenv("FIRST=VALUE1") == 0 ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Getting FIRST from the environment... ");
fflush(stdout);
value = getenv("FIRST");
if ( value && (strcmp(value, "VALUE1") == 0) ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Setting SECOND=VALUE2 in the environment... ");
fflush(stdout);
if ( putenv("SECOND=VALUE2") == 0 ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Getting SECOND from the environment... ");
fflush(stdout);
value = getenv("SECOND");
if ( value && (strcmp(value, "VALUE2") == 0) ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Setting FIRST=NOVALUE in the environment... ");
fflush(stdout);
if ( putenv("FIRST=NOVALUE") == 0 ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Getting FIRST from the environment... ");
fflush(stdout);
value = getenv("FIRST");
if ( value && (strcmp(value, "NOVALUE") == 0) ) {
printf("okay\n");
} else {
printf("failed\n");
}
printf("Checking for non-existent variable... ");
fflush(stdout);
if ( ! getenv("EXISTS") ) {
printf("okay\n");
} else {
printf("failed\n");
}
return(0);
}
#endif /* TEST_MAIN */