// Copyright 2013 the V8 project authors. All rights reserved.
// Copyright (C) 2015-2016 Apple Inc. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
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//       with the distribution.
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//
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"use strict";

// This is based on Octane's RNG.
function createRNG(seed)
{
    return function() {
        // Robert Jenkins' 32 bit integer hash function.
        seed = ((seed + 0x7ed55d16) + (seed << 12))  & 0xffffffff;
        seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff;
        seed = ((seed + 0x165667b1) + (seed << 5))   & 0xffffffff;
        seed = ((seed + 0xd3a2646c) ^ (seed << 9))   & 0xffffffff;
        seed = ((seed + 0xfd7046c5) + (seed << 3))   & 0xffffffff;
        seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff;
        return (seed & 0xfffffff) / 0x10000000;
    };
}

function createRNGWithFixedSeed()
{
    // This uses Octane's initial seed.
    return createRNG(49734321);
}

function createRNGWithRandomSeed()
{
    return createRNG((Math.random() * 4294967296) | 0);
}
