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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*
* Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
*
* To the extent possible under law, the author has dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty.
*
* See <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <inttypes.h>
#include <isc/thread.h>
/*
* This is xoshiro128** 1.0, our 32-bit all-purpose, rock-solid generator.
* It has excellent (sub-ns) speed, a state size (128 bits) that is large
* enough for mild parallelism, and it passes all tests we are aware of.
*
* For generating just single-precision (i.e., 32-bit) floating-point
* numbers, xoshiro128+ is even faster.
*
* The state must be seeded so that it is not everywhere zero.
*/
ISC_THREAD_LOCAL uint32_t seed[4] = { 0 };
static uint32_t
rotl(const uint32_t x, int k) {
return ((x << k) | (x >> (32 - k)));
}
static uint32_t
next(void) {
uint32_t result_starstar, t;
result_starstar = rotl(seed[0] * 5, 7) * 9;
t = seed[1] << 9;
seed[2] ^= seed[0];
seed[3] ^= seed[1];
seed[1] ^= seed[2];
seed[0] ^= seed[3];
seed[2] ^= t;
seed[3] = rotl(seed[3], 11);
return (result_starstar);
}
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