module_random.c

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#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <kuroko/vm.h>
#include <kuroko/util.h>
 
static uint32_t x = 123456789;
static uint32_t y = 362436069;
static uint32_t z = 521288629;
static uint32_t w = 88675123;
 
static int _rand(void) {
    uint32_t t;
 
    t = x ^ (x << 11);
    x = y; y = z; z = w;
    w = w ^ (w >> 19) ^ t ^ (t >> 8);
 
    return (w & RAND_MAX);
}
 
void _srand(unsigned int seed) {
    x = 123456789  ^ (seed << 16) ^ (seed >> 16);
    y = 362436069;
    z = 521288629;
    w = 88675123;
}
 
KRK_Function(random) {
    FUNCTION_TAKES_NONE();
 
    double r = (double)_rand() / (double)(RAND_MAX);
 
    return FLOATING_VAL(r);
}
 
KRK_Function(seed) {
    FUNCTION_TAKES_AT_MOST(1);
    int seed;
 
    if (argc > 0) {
        CHECK_ARG(0,int,krk_integer_type,_seed);
        seed = _seed;
    } else {
        struct timeval tv;
        gettimeofday(&tv,NULL);
 
        seed = tv.tv_sec ^ tv.tv_usec;
    }
 
    _srand(seed);
    return NONE_VAL();
}
 
KRK_Module(random) {
    KRK_DOC(module, "Functions for generating pseudo-random numbers.");
 
    BIND_FUNC(module, random);
    BIND_FUNC(module, seed);
 
    FUNC_NAME(krk,seed)(0,NULL,0);
}