Implement binarySearch method for UArrays (KT-27262)

2019-01-23 18:47:36 +03:00
parent 6cd9858147
commit 550c74bb6b
4 changed files with 292 additions and 1 deletions
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license 
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+@file:kotlin.jvm.JvmMultifileClass
+@file:kotlin.jvm.JvmName("UArraysKt")
+
+package kotlin.collections
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateStandardLib.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+
+/**
+ * Searches the array or the range of the array for the provided [element] using the binary search algorithm.
+ * The array is expected to be sorted, otherwise the result is undefined.
+ * 
+ * If the array contains multiple elements equal to the specified [element], there is no guarantee which one will be found.
+ * 
+ * @return the index of the element, if it is contained in the array within the specified range;
+ * otherwise, the inverted insertion point `(-insertion point - 1)`.
+ * The insertion point is defined as the index at which the element should be inserted,
+ * so that the array (or the specified subrange of array) still remains sorted.
+ */
+@SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
+public fun UIntArray.binarySearch(element: UInt, fromIndex: Int = 0, toIndex: Int = size): Int {
+    AbstractList.checkRangeIndexes(fromIndex, toIndex, size)
+    val signedElement = element.toInt()
+    var low = fromIndex
+    var high = toIndex - 1
+    while (low <= high) {
+        val mid = (low + high).ushr(1) // safe from overflows
+        val midVal = storage[mid]
+        val cmp = uintCompare(midVal, signedElement)
+        if (cmp < 0)
+            low = mid + 1
+        else if (cmp > 0)
+            high = mid - 1
+        else
+            return mid // key found
+    }
+    return -(low + 1)  // key not found
+}
+
+/**
+ * Searches the array or the range of the array for the provided [element] using the binary search algorithm.
+ * The array is expected to be sorted, otherwise the result is undefined.
+ * 
+ * If the array contains multiple elements equal to the specified [element], there is no guarantee which one will be found.
+ * 
+ * @return the index of the element, if it is contained in the array within the specified range;
+ * otherwise, the inverted insertion point `(-insertion point - 1)`.
+ * The insertion point is defined as the index at which the element should be inserted,
+ * so that the array (or the specified subrange of array) still remains sorted.
+ */
+@SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
+public fun ULongArray.binarySearch(element: ULong, fromIndex: Int = 0, toIndex: Int = size): Int {
+    AbstractList.checkRangeIndexes(fromIndex, toIndex, size)
+    val signedElement = element.toLong()
+    var low = fromIndex
+    var high = toIndex - 1
+    while (low <= high) {
+        val mid = (low + high).ushr(1) // safe from overflows
+        val midVal = storage[mid]
+        val cmp = ulongCompare(midVal, signedElement)
+        if (cmp < 0)
+            low = mid + 1
+        else if (cmp > 0)
+            high = mid - 1
+        else
+            return mid // key found
+    }
+    return -(low + 1)  // key not found
+}
+
+/**
+ * Searches the array or the range of the array for the provided [element] using the binary search algorithm.
+ * The array is expected to be sorted, otherwise the result is undefined.
+ * 
+ * If the array contains multiple elements equal to the specified [element], there is no guarantee which one will be found.
+ * 
+ * @return the index of the element, if it is contained in the array within the specified range;
+ * otherwise, the inverted insertion point `(-insertion point - 1)`.
+ * The insertion point is defined as the index at which the element should be inserted,
+ * so that the array (or the specified subrange of array) still remains sorted.
+ */
+@SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
+public fun UByteArray.binarySearch(element: UByte, fromIndex: Int = 0, toIndex: Int = size): Int {
+    AbstractList.checkRangeIndexes(fromIndex, toIndex, size)
+    val signedElement = element.toInt()
+    var low = fromIndex
+    var high = toIndex - 1
+    while (low <= high) {
+        val mid = (low + high).ushr(1) // safe from overflows
+        val midVal = storage[mid]
+        val cmp = uintCompare(midVal.toInt(), signedElement)
+        if (cmp < 0)
+            low = mid + 1
+        else if (cmp > 0)
+            high = mid - 1
+        else
+            return mid // key found
+    }
+    return -(low + 1)  // key not found
+}
+
+/**
+ * Searches the array or the range of the array for the provided [element] using the binary search algorithm.
+ * The array is expected to be sorted, otherwise the result is undefined.
+ * 
+ * If the array contains multiple elements equal to the specified [element], there is no guarantee which one will be found.
+ * 
+ * @return the index of the element, if it is contained in the array within the specified range;
+ * otherwise, the inverted insertion point `(-insertion point - 1)`.
+ * The insertion point is defined as the index at which the element should be inserted,
+ * so that the array (or the specified subrange of array) still remains sorted.
+ */
+@SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
+public fun UShortArray.binarySearch(element: UShort, fromIndex: Int = 0, toIndex: Int = size): Int {
+    AbstractList.checkRangeIndexes(fromIndex, toIndex, size)
+    val signedElement = element.toInt()
+    var low = fromIndex
+    var high = toIndex - 1
+    while (low <= high) {
+        val mid = (low + high).ushr(1) // safe from overflows
+        val midVal = storage[mid]
+        val cmp = uintCompare(midVal.toInt(), signedElement)
+        if (cmp < 0)
+            low = mid + 1
+        else if (cmp > 0)
+            high = mid - 1
+        else
+            return mid // key found
+    }
+    return -(low + 1)  // key not found
+}
+