random.c

Go to the documentation of this file.

#include <stdlib.h>
#include <SDL.h>
#include <time.h>

#ifndef WIN32

static FILE *urand = NULL;
#endif                                                                       

void RandInit() {
    #ifndef WIN32
    // see if /dev/urandom (pretty common on UNIX-like systems) has already
    // been opened, and if not, open it
    if ((urand == NULL) && ((urand = fopen("/dev/urandom", "rb")) == NULL))
    #endif
    {
        // couldn't open /dev/urandom, or on systen that doesn't support it
        srand((unsigned int)time(NULL));
    }
}

Uint32 RandNum() {
    #ifndef WIN32
    // check for already open file handle to /dev/urandom
    if (urand) {
        int num;
        // read in the next 4 bytes of randomness
        fread(&num, 4, 1, urand);
        return num;
    }
    #endif
    // use the ANSI C interface to a pseudo random number generator
    return (rand() << 16) | rand();
}

void RandUninit() {
    #ifndef WIN32
    // check for already open file handle to /dev/urandom
    if (urand) {
        // close the file
        fclose(urand);
    }
    #endif
}

---