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