#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>

#include "random.h"

#define RAND_BUF_SIZE	1024
#define RND_DEV		"/dev/urandom"

unsigned int get_random(void)
{
	static int rndbuf[RAND_BUF_SIZE];
	static int index = RAND_BUF_SIZE;
	int fd, error, i = 0, ret;

	if (index < RAND_BUF_SIZE)
		return rndbuf[index++];

	fd = open(RND_DEV, O_RDONLY);
	if (fd < 0) {
		error = errno;
		fprintf(stderr, "Error opening file %s: %s\n",
			RND_DEV, strerror(error));
		ret = error;
		goto err;
	}

	do {
		ret = read(fd, rndbuf + i,
			  RAND_BUF_SIZE * (sizeof(rndbuf[0]) - i));

		if (ret <= 0) {
			error = errno;
			fprintf(stderr, "Error reading file %s: %s\n",
				RND_DEV, strerror(error));
			ret = error;
			goto err;
		}

		i += ret;
	} while (i < RAND_BUF_SIZE * sizeof(rndbuf[0]));
	index = 0;

	close(fd);
	return get_random();

err:
	close(fd);
	return ret;
}

double get_random_double(void)
{
	return get_random() / (double)((unsigned int)(-1));
}