1 files changed, 63 insertions, 0 deletions
diff --git a/lib/isc/xoshiro128starstar.c b/lib/isc/xoshiro128starstar.c
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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);
+}