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/* ISC license. */
#include <skalibs/sysdeps.h>
#ifdef SKALIBS_HASARC4RANDOM
#include <skalibs/nonposix.h>
#include <stdlib.h>
#include <skalibs/random.h>
uint32 random_uint32 (uint32 n)
{
return arc4random_uniform(n) ;
}
#else
#include <skalibs/uint32.h>
#include <skalibs/bytestr.h>
#include <skalibs/random.h>
static inline uint32 random_mask2 (register uint32 n)
{
for (;;)
{
register uint32 m = n | (n >> 1) ;
if (m == n) return n ;
n = m ;
}
}
static inline unsigned int random_nchars (register uint32 n)
{
return n <= 0xff ? 1 :
n <= 0xffff ? 2 :
n <= 0xffffffUL ? 3 : 4 ;
}
uint32 random_uint32 (uint32 n)
{
if (!n) return 0 ;
else
{
uint32 i = n, m = random_mask2(n-1) ;
unsigned int nchars = random_nchars(n) ;
char tmp[4] ;
while (i >= n)
{
random_string(tmp, nchars) ;
byte_zero(tmp + nchars, 4 - nchars) ;
uint32_unpack(tmp, &i) ;
i &= m ;
}
return i ;
}
}
#endif
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