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61 lines
1.7 KiB
Swift
61 lines
1.7 KiB
Swift
//===--- PRNG.swift -------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftShims
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public func rand32() -> UInt32 {
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return _swift_stdlib_cxx11_mt19937()
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}
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public func rand32(exclusiveUpperBound limit: UInt32) -> UInt32 {
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return _swift_stdlib_cxx11_mt19937_uniform(limit)
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}
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public func rand64() -> UInt64 {
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return
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(UInt64(_swift_stdlib_cxx11_mt19937()) << 32) |
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UInt64(_swift_stdlib_cxx11_mt19937())
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}
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public func randInt() -> Int {
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#if arch(i386) || arch(arm)
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return Int(Int32(bitPattern: rand32()))
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#elseif arch(x86_64) || arch(arm64) || arch(powerpc64) || arch(powerpc64le) || arch(s390x)
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return Int(Int64(bitPattern: rand64()))
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#else
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fatalError("unimplemented")
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#endif
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}
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public func randArray64(_ count: Int) -> [UInt64] {
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var result = [UInt64](repeating: 0, count: count)
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for i in result.indices {
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result[i] = rand64()
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}
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return result
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}
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public func randArray(_ count: Int) -> [Int] {
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var result = [Int](repeating: 0, count: count)
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for i in result.indices {
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result[i] = randInt()
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}
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return result
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}
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public func pickRandom<
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C : RandomAccessCollection
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>(_ c: C) -> C.Iterator.Element {
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let i = Int(rand32(exclusiveUpperBound: numericCast(c.count)))
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return c[c.index(c.startIndex, offsetBy: numericCast(i))]
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}
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