Fraction is now NaN capable

src/main/kotlin/ru/dbotthepony/mc/otm/core/Fraction.kt

@@ -43,7 +43,10 @@ inline fun invertCompare(int: Int): Int {
 	return if (int < 0) 1 else -1
 }
 
+private val BI_MINUS_ZERO = BigInteger("-0")
+
 @JvmRecord
+@Suppress("unused")
 data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @JvmField val divisor: BigInteger = BigInteger.ONE, @JvmField val compact: Boolean = true) {
 	@JvmOverloads constructor(value: Long, compact: Boolean = true) : this(BigInteger.valueOf(value), compact = compact)
 	@JvmOverloads constructor(value: Int, compact: Boolean = true) : this(BigInteger.valueOf(value.toLong()), compact = compact)
@@ -69,6 +72,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		val c = divisor.signum()
 
 		if (a != b && a != c) {
+			if (divisor == BigInteger.ZERO || divisor == BI_MINUS_ZERO)
+				return Fraction(-value, -divisor)
+
 			val mod = value % divisor
 
 			if (mod == BigInteger.ZERO)
@@ -77,6 +83,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 			return Fraction(-value, -divisor)
 		}
 
+		if (divisor == BigInteger.ZERO || divisor == BI_MINUS_ZERO)
+			return this
+
 		val mod = value % divisor
 
 		if (mod == BigInteger.ZERO)
@@ -86,13 +95,19 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	fun isZero(): Boolean {
+		if (isNaN()) return false
 		return value == BigInteger.ZERO
 	}
 
 	fun compact(): Fraction {
+		if (isNaN()) return this
+
 		if (value == BigInteger.ZERO || value == BigInteger.ONE || divisor == BigInteger.ONE)
 			return this
 
+		if (divisor == BigInteger.ZERO || divisor == BI_MINUS_ZERO)
+			return this
+
 		val mod = value % divisor
 
 		if (mod == BigInteger.ZERO)
@@ -102,6 +117,8 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	fun canonize(): Fraction {
+		if (isNaN()) return this
+
 		if (value == BigInteger.ZERO || value == BigInteger.ONE || divisor == BigInteger.ONE || divisor == BigInteger.ZERO)
 			return this
 
@@ -120,6 +137,8 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		if (other == null)
 			return false
 
+		if (isNaN() || other.isNaN()) return false
+
 		val a = compact()
 		val b = other.compact()
 
@@ -127,6 +146,8 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun compareTo(other: Fraction): Int {
+		if (isNaN() || other.isNaN()) return 0
+
 		if (divisor == other.divisor)
 			return value.compareTo(other.value)
 
@@ -156,7 +177,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		return cmp
 	}
 
-	fun plusCompact(other: Fraction): Fraction {
+	private fun plusCompact(other: Fraction): Fraction {
+		if (isNaN()) return this
+
 		if (divisor == other.divisor) {
 			if (divisor == BigInteger.ONE)
 				return Fraction(value + other.value)
@@ -166,6 +189,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 			if (new.compareTo(BigInteger.ZERO) == 0)
 				return ZERO
 
+			if (divisor == BigInteger.ZERO || divisor == BI_MINUS_ZERO)
+				return Fraction(new, divisor)
+
 			val mod = new % divisor
 
 			if (mod == BigInteger.ZERO)
@@ -176,6 +202,10 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 
 		val new = value * other.divisor + other.value * divisor
 		val div = divisor * other.divisor
+
+		if (div == BigInteger.ZERO || div == BI_MINUS_ZERO)
+			return Fraction(new, div)
+
 		val mod = new % div
 
 		if (mod == BigInteger.ZERO)
@@ -185,6 +215,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun plus(other: Fraction): Fraction {
+		if (isNaN()) return this
+		if (other.isNaN()) return other
+
 		if (compact)
 			return plusCompact(other)
 
@@ -195,7 +228,7 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		return Fraction(value * other.divisor + other.value * divisor, divisor * other.divisor, compact = false)
 	}
 
-	fun minusCompact(other: Fraction): Fraction {
+	private fun minusCompact(other: Fraction): Fraction {
 		if (divisor == other.divisor) {
 			if (divisor == BigInteger.ONE)
 				return Fraction(value - other.value)
@@ -205,6 +238,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 			if (new.compareTo(BigInteger.ZERO) == 0)
 				return ZERO
 
+			if (divisor == BigInteger.ZERO || divisor == BI_MINUS_ZERO)
+				return Fraction(new, divisor)
+
 			val mod = new % divisor
 
 			if (mod == BigInteger.ZERO)
@@ -215,6 +251,10 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 
 		val new = value * other.divisor - other.value * divisor
 		val div = divisor * other.divisor
+
+		if (div == BigInteger.ZERO || div == BI_MINUS_ZERO)
+			return Fraction(new, div)
+
 		val mod = new % div
 
 		if (mod == BigInteger.ZERO)
@@ -224,6 +264,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun minus(other: Fraction): Fraction {
+		if (isNaN()) return this
+		if (other.isNaN()) return other
+
 		if (compact)
 			return minusCompact(other)
 
@@ -234,13 +277,17 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		return Fraction(value * other.divisor - other.value * divisor, divisor * other.divisor, compact = false)
 	}
 
-	fun timesCompact(other: Fraction): Fraction {
+	private fun timesCompact(other: Fraction): Fraction {
 		val new = value * other.value
 
 		if (new.compareTo(BigInteger.ZERO) == 0)
 			return ZERO
 
 		val div = divisor * other.divisor
+
+		if (div == BigInteger.ZERO || div == BI_MINUS_ZERO)
+			return Fraction(new, div)
+
 		val mod = new % div
 
 		if (mod == BigInteger.ZERO)
@@ -250,19 +297,26 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun times(other: Fraction): Fraction {
+		if (isNaN()) return this
+		if (other.isNaN()) return other
+
 		if (compact)
 			return timesCompact(other)
 
 		return Fraction(value * other.value, divisor * other.divisor, compact = false)
 	}
 
-	fun divCompact(other: Fraction): Fraction {
+	private fun divCompact(other: Fraction): Fraction {
 		val new = value * other.divisor
 
 		if (new.compareTo(BigInteger.ZERO) == 0)
 			return ZERO
 
 		val div = divisor * other.value
+
+		if (div == BigInteger.ZERO || div == BI_MINUS_ZERO)
+			return Fraction(new, div)
+
 		val mod = new % div
 
 		if (mod == BigInteger.ZERO)
@@ -272,6 +326,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun div(other: Fraction): Fraction {
+		if (isNaN()) return this
+		if (other.isNaN()) return other
+
 		if (compact)
 			return divCompact(other)
 
@@ -279,6 +336,7 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	operator fun unaryMinus(): Fraction {
+		if (isNaN()) return this
 		return Fraction(-value, divisor)
 	}
 
@@ -347,19 +405,27 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	 */
 
 	operator fun rem(other: Fraction): Fraction {
+		if (isNaN()) return this
+		if (other.isNaN()) return other
 		return Fraction((this / other).wholePart())
 	}
 
 	// Преобразования
 	fun toFloat(): Float {
+		if (isNaN()) return Float.NaN
 		return (value / divisor).toFloat() + ((value % divisor).toFloat() / divisor.toFloat())
 	}
 
 	fun toDouble(): Double {
+		if (isNaN()) return Double.NaN
 		return (value / divisor).toDouble() + ((value % divisor).toDouble() / divisor.toDouble())
 	}
 
 	fun toByteArray(): ByteArray {
+		if (isNaN()) {
+			return byteArrayOf(1, 0, 1, 0)
+		}
+
 		val bytesA = value.toByteArray()
 		val bytesB = divisor.toByteArray()
 
@@ -367,41 +433,52 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	fun toInt(): Int {
+		if (isNaN()) throw ArithmeticException("Fraction is not a number")
 		return (value / divisor).toInt()
 	}
 
 	fun toLong(): Long {
+		if (isNaN()) throw ArithmeticException("Fraction is not a number")
 		return (value / divisor).toLong()
 	}
 
 	@JvmOverloads
 	fun toBigDecimal(context: MathContext = DEFAULT_MATH_CONTEXT): BigDecimal {
+		if (isNaN()) throw ArithmeticException("Fraction is not a number")
 		return BigDecimal(value).divide(BigDecimal(divisor), context)
 	}
 
 	// Утилиты
 	fun wholePart(): BigInteger {
+		if (isNaN()) throw ArithmeticException("Fraction is not a number")
 		return value / divisor
 	}
 
 	fun fractionPart(): Fraction {
+		if (isNaN()) return this
 		return Fraction(value % divisor, divisor)
 	}
 
 	fun modPart(): BigInteger {
+		if (isNaN()) throw ArithmeticException("Fraction is not a number")
 		return value % divisor
 	}
 
 	override fun toString(): String {
+		if (isNaN()) return "NaN"
+
 		return "$value/$divisor"
 	}
 
 	fun formattedString(): String {
+		if (isNaN()) return "NaN"
 		return "${wholePart()} ${modPart()}/$divisor"
 	}
 
 	@JvmOverloads
 	fun decimalString(nums: Int = 2, strict: Boolean = false): String {
+		if (isNaN()) return "NaN"
+
 		val whole = wholePart()
 		val fraction = modPart()
 
@@ -438,6 +515,8 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 	}
 
 	fun signnum(): Int {
+		if (isNaN()) return 0
+
 		val a = value.signum()
 		val b = divisor.signum()
 
@@ -503,7 +582,10 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 
 	// Позволяет получить процент от деления данного на divisor с точностью до 5 цифр
 	fun percentage(divisor: Fraction): Float {
+		if (isNaN() || divisor.isNaN()) return Float.NaN
+
 		val mul = (this * TEN_THOUSAND) / divisor
+		if (mul.isNaN()) return Float.NaN
 
 		return mul.wholePart().toFloat() / 10_000f
 	}
@@ -512,6 +594,9 @@ data class Fraction @JvmOverloads constructor(@JvmField val value: BigInteger, @
 		@JvmField
 		val ZERO = Fraction(BigInteger.ZERO)
 
+		@JvmField
+		val NaN = Fraction(BigInteger.ZERO, BigInteger.ZERO)
+
 		@JvmField
 		val ONE_HUNDRED = Fraction(BigInteger.valueOf(100))
 

src/test/kotlin/ru/dbotthepony/mc/otm/tests/FractionTests.kt

@@ -2,6 +2,7 @@ package ru.dbotthepony.mc.otm.tests
 
 import org.junit.jupiter.api.DisplayName
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
 import ru.dbotthepony.mc.otm.core.Fraction
 import java.math.BigDecimal
 import java.math.BigInteger
@@ -36,6 +37,34 @@ object FractionTests {
 		println("canonical -1/-2 == ${Fraction(-1, -2).canonize()}")
 	}
 
+	@Test
+	@DisplayName("Fraction NaN behavior")
+	fun nan() {
+		assert((Fraction.NaN + Fraction.ONE).isNaN())
+		assert((Fraction.NaN - Fraction.ONE).isNaN())
+		assert((Fraction.NaN / Fraction.ONE).isNaN())
+		assert((Fraction.NaN * Fraction.ONE).isNaN())
+
+		assert((Fraction.ONE + Fraction.NaN).isNaN())
+		assert((Fraction.ONE - Fraction.NaN).isNaN())
+		assert((Fraction.ONE / Fraction.NaN).isNaN())
+		assert((Fraction.ONE * Fraction.NaN).isNaN())
+
+		assert((Fraction.ONE / Fraction.ZERO).isNaN())
+		assert((Fraction.ONE * Fraction(0, 0)).isNaN())
+		assert((Fraction.ONE * Fraction(1, 0)).isNaN())
+
+		assert(Fraction.NaN.toFloat().isNaN())
+		assert(Fraction.NaN.toDouble().isNaN())
+
+		assertThrows<ArithmeticException> {Fraction.NaN.toInt()}
+		assertThrows<ArithmeticException> {Fraction.NaN.toLong()}
+		assertThrows<ArithmeticException> {Fraction.NaN.wholePart()}
+
+		assert(Fraction.fromByteArray(Fraction.NaN.toByteArray()).isNaN())
+		assert(Fraction.NaN.percentage(Fraction.ONE).isNaN())
+	}
+
 	@Test
 	@DisplayName("Fraction comparison")
 	fun equality() {