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Remove arc4random_uniform from arc4random.c

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This was previously moved into its own file (matching OpenBSD) which
prematurely committed in commit 73541f2.
This commit is contained in:
Darren Tucker 2022-09-02 14:17:28 +10:00
parent 5f45c2395c
commit c83e467ead
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1 changed files with 0 additions and 38 deletions
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38
openbsd-compat/arc4random.c
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@ -242,44 +242,6 @@ arc4random_buf(void *_buf, size_t n)
}
#endif /* !defined(HAVE_ARC4RANDOM_BUF) && defined(HAVE_ARC4RANDOM) */
#ifndef HAVE_ARC4RANDOM_UNIFORM
/*
* Calculate a uniformly distributed random number less than upper_bound
* avoiding "modulo bias".
*
* Uniformity is achieved by generating new random numbers until the one
* returned is outside the range [0, 2**32 % upper_bound). This
* guarantees the selected random number will be inside
* [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
* after reduction modulo upper_bound.
*/
u_int32_t
arc4random_uniform(u_int32_t upper_bound)
{
u_int32_t r, min;
if (upper_bound < 2)
return 0;
/* 2**32 % x == (2**32 - x) % x */
min = -upper_bound % upper_bound;
/*
* This could theoretically loop forever but each retry has
* p > 0.5 (worst case, usually far better) of selecting a
* number inside the range we need, so it should rarely need
* to re-roll.
*/
for (;;) {
r = arc4random();
if (r >= min)
break;
}
return r % upper_bound;
}
#endif /* !HAVE_ARC4RANDOM_UNIFORM */
#if 0
/*-------- Test code for i386 --------*/
#include <stdio.h>