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// Copyright 2023 Alejandro Colomar <alx@kernel.org>
// SPDX-License-Identifier: LGPL-3.0-or-later WITH LGPL-3.0-linking-exception
#ifndef INCLUDE_C_RAND_CSRAND_CSRAND_UNIFORM_H_
#define INCLUDE_C_RAND_CSRAND_CSRAND_UNIFORM_H_
#include <stdint.h>
#include <c/bit/ceil.h>
#include <c/rand/csrand/csrand.h>
#pragma clang assume_nonnull begin
inline uint64_t c_csrand64_uniform(uint64_t n);
inline uint64_t c_csrand64_interval(uint64_t min, uint64_t max);
inline uint64_t
c_csrand64_uniform(uint64_t n)
{
uint64_t r, max, mask;
max = n - 1;
mask = c_bit_ceil_wrap_64(n) - 1;
do {
r = c_csrand64();
r &= mask;
} while (r > max);
return r;
}
inline uint64_t
c_csrand64_interval(uint64_t min, uint64_t max)
{
return c_csrand64_uniform(max - min + 1) + min;
}
#pragma clang assume_nonnull end
#endif // Header guard
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