Provide Xoshiro256**, Xoshiro256++ and LCG64 PRNGs

gradle.properties

@@ -4,7 +4,7 @@ kotlin.code.style=official
 specifyKotlinAsDependency=false
 
 projectGroup=ru.dbotthepony.kommons
-projectVersion=3.1.3
+projectVersion=3.2.0
 
 guavaDepVersion=33.0.0
 gsonDepVersion=2.8.9

src/main/kotlin/ru/dbotthepony/kommons/random/LCG64Random.kt

@@ -0,0 +1,27 @@
+package ru.dbotthepony.kommons.random
+
+import java.util.random.RandomGenerator
+
+/**
+ * Classical LCG PRNG, utilizing [MULTIPLIER] and [INCREMENT] as constants.
+ *
+ * Internal state is presented as 64-bit integer, and high-order bits of internal state are
+ * used to generate numbers.
+ */
+open class LCG64Random(private var seed: Long) : RandomGenerator {
+	final override fun nextLong(): Long {
+		val a = nextInt().toLong()
+		val b = nextInt().toLong() and 0xFFFFFFFFL
+		return a.shl(32) or b
+	}
+
+	final override fun nextInt(): Int {
+		this.seed = MULTIPLIER * this.seed + INCREMENT
+		return this.seed.ushr(32).toInt()
+	}
+
+	companion object {
+		const val MULTIPLIER = 6364136223846793005
+		const val INCREMENT = 1442695040888963407
+	}
+}

src/main/kotlin/ru/dbotthepony/kommons/random/Xoshiro256PlusPlusRandom.kt

@@ -0,0 +1,58 @@
+package ru.dbotthepony.kommons.random
+
+import java.util.random.RandomGenerator
+
+open class Xoshiro256PlusPlusRandom protected constructor(
+	private var s0: Long,
+	private var s1: Long,
+	private var s2: Long,
+	private var s3: Long,
+	mark: Nothing?
+) : RandomGenerator {
+	init {
+		if (s0 or s1 or s2 or s3 == 0L) {
+			s0 = 0x73CF3D83FFF44FF3L
+			s1 = 0x6412312B70F3CD37L
+			s2 = -0X6BB4C4E1327BFDCFL
+			s3 = -0X4BE0F5BB5F3F5240L
+		}
+	}
+
+	constructor(s0: Long, s1: Long, s2: Long, s3: Long) : this(s0, s1, s2, s3, null) {
+		// discard some values so generator can get going if provided seed was "weak"
+		for (i in 0 until 32)
+			nextLong()
+	}
+
+	constructor(seed: Long) : this(1L, 0L, 0L, 0L, null) {
+		val rng = LCG64Random(seed)
+		s0 = rng.nextLong()
+		s1 = rng.nextLong()
+		s2 = rng.nextLong()
+		s3 = rng.nextLong()
+	}
+
+	final override fun nextLong(): Long {
+		val result = (s0 + s3).rotateLeft(23) + s1
+		val t = s1.shl(17)
+		s2 = s2.xor(s0)
+		s3 = s3.xor(s1)
+		s1 = s1.xor(s2)
+		s0 = s0.xor(s3)
+		s2 = s2.xor(t)
+		s3 = s3.rotateLeft(45)
+		return result
+	}
+
+	companion object {
+		@JvmStatic
+		fun raw(
+			s0: Long,
+			s1: Long,
+			s2: Long,
+			s3: Long,
+		): Xoshiro256PlusPlusRandom {
+			return Xoshiro256PlusPlusRandom(s0, s1, s2, s3, null)
+		}
+	}
+}

src/main/kotlin/ru/dbotthepony/kommons/random/Xoshiro256StarStarRandom.kt

@@ -0,0 +1,58 @@
+package ru.dbotthepony.kommons.random
+
+import java.util.random.RandomGenerator
+
+open class Xoshiro256StarStarRandom protected constructor(
+	private var s0: Long,
+	private var s1: Long,
+	private var s2: Long,
+	private var s3: Long,
+	mark: Nothing?
+) : RandomGenerator {
+	init {
+		if (s0 or s1 or s2 or s3 == 0L) {
+			s0 = 0x73CF3D83FFF44FF3L
+			s1 = 0x6412312B70F3CD37L
+			s2 = -0X6BB4C4E1327BFDCFL
+			s3 = -0X4BE0F5BB5F3F5240L
+		}
+	}
+
+	constructor(s0: Long, s1: Long, s2: Long, s3: Long) : this(s0, s1, s2, s3, null) {
+		// discard some values so generator can get going if provided seed was "weak"
+		for (i in 0 until 32)
+			nextLong()
+	}
+
+	constructor(seed: Long) : this(1L, 0L, 0L, 0L, null) {
+		val rng = LCG64Random(seed)
+		s0 = rng.nextLong()
+		s1 = rng.nextLong()
+		s2 = rng.nextLong()
+		s3 = rng.nextLong()
+	}
+
+	final override fun nextLong(): Long {
+		val result = (s1 * 5).rotateLeft(7) * 9
+		val t = s1.shl(17)
+		s2 = s2.xor(s0)
+		s3 = s3.xor(s1)
+		s1 = s1.xor(s2)
+		s0 = s0.xor(s3)
+		s2 = s2.xor(t)
+		s3 = s3.rotateLeft(45)
+		return result
+	}
+
+	companion object {
+		@JvmStatic
+		fun raw(
+			s0: Long,
+			s1: Long,
+			s2: Long,
+			s3: Long,
+		): Xoshiro256StarStarRandom {
+			return Xoshiro256StarStarRandom(s0, s1, s2, s3, null)
+		}
+	}
+}