KT-33761 Add reduceRightOrNull

2019-12-13 19:06:59 +01:00
parent f5d696d3c4
commit 06008c40ab
7 changed files with 321 additions and 0 deletions
@@ -13136,6 +13136,141 @@ public inline fun CharArray.reduceRightIndexed(operation: (index: Int, Char, acc
    return accumulator
 }

+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun <S, T : S> Array<out T>.reduceRightOrNull(operation: (T, acc: S) -> S): S? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator: S = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun ByteArray.reduceRightOrNull(operation: (Byte, acc: Byte) -> Byte): Byte? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun ShortArray.reduceRightOrNull(operation: (Short, acc: Short) -> Short): Short? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun IntArray.reduceRightOrNull(operation: (Int, acc: Int) -> Int): Int? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun LongArray.reduceRightOrNull(operation: (Long, acc: Long) -> Long): Long? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun FloatArray.reduceRightOrNull(operation: (Float, acc: Float) -> Float): Float? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun DoubleArray.reduceRightOrNull(operation: (Double, acc: Double) -> Double): Double? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun BooleanArray.reduceRightOrNull(operation: (Boolean, acc: Boolean) -> Boolean): Boolean? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
+/**
+ * Accumulates value starting with last element and applying [operation] from right to left to each element and current accumulator value. Returns null if the array is empty.
+ */
+@SinceKotlin("1.3")
+@ExperimentalStdlibApi
+public inline fun CharArray.reduceRightOrNull(operation: (Char, acc: Char) -> Char): Char? {
+    var index = lastIndex
+    if (index < 0) return null
+    var accumulator = get(index--)
+    while (index >= 0) {
+        accumulator = operation(get(index--), accumulator)
+    }
+    return accumulator
+}
+
 /**
 * Returns the sum of all values produced by [selector] function applied to each element in the array.
 */