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/* utility.c - burneye2 supporting functions
*
* by scut
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <utility.h>
int quiet = 0;
int rand_fd = -1;
int
fnote (const char *fmt, ...)
{
int len;
va_list ap;
if (quiet)
return (0);
va_start (ap, fmt);
len = vfprintf (stderr, fmt, ap);
va_end (ap);
return (len);
}
void
be_randinit_file (const char *filename)
{
if (rand_fd != -1)
return;
rand_fd = open (filename, 0);
if (rand_fd < 0)
exit (EXIT_FAILURE);
}
void
be_randinit (void)
{
be_randinit_file ("/dev/urandom");
}
void
be_randend (void)
{
close (rand_fd);
rand_fd = -1;
}
unsigned int
be_random (unsigned int max)
{
ssize_t nret;
unsigned int tmp;
if (rand_fd == -1)
be_randinit ();
nret = read (rand_fd, &tmp, sizeof (tmp));
if (nret != sizeof (tmp)) {
if (nret < 0)
perror ("be_random, read random-file");
else
fprintf (stderr, "be_random, random data depleted\n");
exit (EXIT_FAILURE);
}
/* 0 denotes special 0 to 2^32 - 1 range
*/
if (max == 0)
return (tmp);
return (tmp % max);
}
int
be_random_coin (double prob)
{
double rand;
rand = (double) be_random (UINT_MAX);
rand /= (double) UINT_MAX;
if (rand <= prob)
return (1);
return (0);
}
unsigned int
be_random_prob (unsigned int items_count, double *items_prob)
{
double sum = 0.0,
rand;
unsigned int in;
for (in = 0 ; in < items_count ; ++in)
sum += items_prob[in];
in = be_random (UINT_MAX);
rand = in;
rand /= (double) UINT_MAX;
rand *= sum;
sum = 0.0;
for (in = 0 ; sum < rand && in < items_count ; ++in)
sum += items_prob[in];
if (in > 0)
in -= 1;
return (in);
}
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