55 lines
2.4 KiB
JavaScript
55 lines
2.4 KiB
JavaScript
// Copyright 2013 the V8 project authors. All rights reserved.
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// Copyright (C) 2015-2016 Apple Inc. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"use strict";
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// This is based on Octane's RNG.
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function createRNG(seed)
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{
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return function() {
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// Robert Jenkins' 32 bit integer hash function.
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seed = ((seed + 0x7ed55d16) + (seed << 12)) & 0xffffffff;
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seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff;
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seed = ((seed + 0x165667b1) + (seed << 5)) & 0xffffffff;
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seed = ((seed + 0xd3a2646c) ^ (seed << 9)) & 0xffffffff;
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seed = ((seed + 0xfd7046c5) + (seed << 3)) & 0xffffffff;
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seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff;
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return (seed & 0xfffffff) / 0x10000000;
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};
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}
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function createRNGWithFixedSeed()
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{
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// This uses Octane's initial seed.
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return createRNG(49734321);
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}
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function createRNGWithRandomSeed()
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{
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return createRNG((Math.random() * 4294967296) | 0);
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}
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