50 lines
2.0 KiB
Swift
50 lines
2.0 KiB
Swift
//
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// SeededRandomNumberGenerator.swift
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// WolfNumerics
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//
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// Created by Wolf McNally on 10/28/18.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#if canImport(GameKit)
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import GameKit
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@available(iOS 9.0, macOS 10.11, tvOS 9.0, *)
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public final class SeededRandomNumberGenerator: RandomNumberGenerator {
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private let source: GKMersenneTwisterRandomSource
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private let distribution: GKRandomDistribution
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public init(seed: UInt64) {
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source = GKMersenneTwisterRandomSource(seed: seed)
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distribution = GKRandomDistribution(randomSource: source, lowestValue: Int(UInt16.min), highestValue: Int(UInt16.max))
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}
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public convenience init(seed: Int) {
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self.init(seed: UInt64(seed))
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}
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public func next() -> UInt64 {
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return (UInt64(distribution.nextInt()) << 48)
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| (UInt64(distribution.nextInt()) << 32)
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| (UInt64(distribution.nextInt()) << 16)
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| (UInt64(distribution.nextInt()) << 0)
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}
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}
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#endif
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