57 lines
1.6 KiB
Scala
57 lines
1.6 KiB
Scala
package lila.common
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import scala.collection.mutable.StringBuilder
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abstract class Random {
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protected def current: java.util.Random
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def nextBoolean(): Boolean = current.nextBoolean()
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def nextDouble(): Double = current.nextDouble()
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def nextFloat(): Float = current.nextFloat()
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def nextInt(): Int = current.nextInt()
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def nextInt(n: Int): Int = current.nextInt(n)
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def nextLong(): Long = current.nextLong()
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def nextGaussian(): Double = current.nextGaussian()
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def nextBytes(len: Int): Array[Byte] = {
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val bytes = new Array[Byte](len)
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current.nextBytes(bytes)
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bytes
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}
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private def nextAlphanumeric(): Char = {
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val chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
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chars charAt nextInt(chars.length) // Constant time
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}
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def nextString(len: Int): String = {
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val sb = new StringBuilder(len)
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for (_ <- 0 until len) sb += nextAlphanumeric()
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sb.result()
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}
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def shuffle[T, C](xs: IterableOnce[T])(implicit bf: scala.collection.BuildFrom[xs.type, T, C]): C =
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new scala.util.Random(current).shuffle(xs)
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def oneOf[A](vec: Vector[A]): Option[A] =
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vec.nonEmpty ?? {
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vec lift nextInt(vec.size)
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}
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// odds(1) = 100% true
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// odds(2) = 50% true
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// odds(3) = 33% true
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def odds(n: Int): Boolean = nextInt(n) == 0
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}
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object ThreadLocalRandom extends Random {
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override def current = java.util.concurrent.ThreadLocalRandom.current
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def nextLong(n: Long): Long = current.nextLong(n)
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}
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object SecureRandom extends Random {
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override val current = new java.security.SecureRandom()
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}
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