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In-place reversing.

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#KT-9034
This commit is contained in:
Ilya Gorbunov
2015-10-30 18:30:25 +03:00
parent 1400bdc09a
commit 4fc54a12b8
7 changed files with 200 additions and 27 deletions
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libraries/stdlib/src/generated/_Arrays.kt
+136
View File
@@ -4143,6 +4143,142 @@ public inline fun ShortArray.takeWhile(predicate: (Short) -> Boolean): List<Shor
return list
}
/**
* Reverses elements in the array in-place.
*/
public fun <T> Array<out T>.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
val _this = this as Array<T>
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = _this[index]
_this[index] = _this[reverseIndex]
_this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun BooleanArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun ByteArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun CharArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun DoubleArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun FloatArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun IntArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun LongArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Reverses elements in the array in-place.
*/
public fun ShortArray.reverse(): Unit {
val midPoint = (size / 2) - 1
if (midPoint < 0) return
var reverseIndex = lastIndex
for (index in 0..midPoint) {
val tmp = this[index]
this[index] = this[reverseIndex]
this[reverseIndex] = tmp
reverseIndex--
}
}
/**
* Returns a list with elements in reversed order.
*/
libraries/stdlib/src/generated/_Collections.kt
+7
View File
@@ -789,6 +789,13 @@ public inline fun <T> Iterable<T>.takeWhile(predicate: (T) -> Boolean): List<T>
return list
}
/**
* Reverses elements in the collection in-place.
*/
public fun <T> MutableList<T>.reverse(): Unit {
java.util.Collections.reverse(this)
}
/**
* Returns a list with elements in reversed order.
*/
libraries/stdlib/test/collections/ArraysTest.kt
+11
View File
@@ -546,6 +546,17 @@ class ArraysTest {
} is UnsupportedOperationException)
}
@test fun reverseInPlace() {
assertArrayNotSameButEquals(intArrayOf(3, 2, 1), intArrayOf(1, 2, 3).apply { reverse() })
assertArrayNotSameButEquals(byteArrayOf(3, 2, 1), byteArrayOf(1, 2, 3).apply { reverse() })
assertArrayNotSameButEquals(shortArrayOf(3, 2, 1), shortArrayOf(1, 2, 3).apply { reverse() })
assertArrayNotSameButEquals(longArrayOf(3, 2, 1), longArrayOf(1, 2, 3).apply { reverse() })
assertArrayNotSameButEquals(floatArrayOf(3F, 2F, 1F), floatArrayOf(1F, 2F, 3F).apply { reverse() })
assertArrayNotSameButEquals(doubleArrayOf(3.0, 2.0, 1.0), doubleArrayOf(1.0, 2.0, 3.0).apply { reverse() })
assertArrayNotSameButEquals(charArrayOf('3', '2', '1'), charArrayOf('1', '2', '3').apply { reverse() })
assertArrayNotSameButEquals(booleanArrayOf(false, false, true), booleanArrayOf(true, false, false).apply { reverse() })
}
@test fun reversed() {
expect(listOf(3, 2, 1)) { intArrayOf(1, 2, 3).reversed() }
expect(listOf<Byte>(3, 2, 1)) { byteArrayOf(1, 2, 3).reversed() }
libraries/stdlib/test/collections/CollectionTest.kt
+20 -13
View File
@@ -310,22 +310,29 @@ class CollectionTest {
}
}
@test fun reverse() {
@test fun reverseInPlace() {
val data = arrayListOf<String>()
data.reverse()
assertTrue(data.isEmpty())
data.add("foo")
data.reverse()
assertEquals(listOf("foo"), data)
data.add("bar")
data.reverse()
assertEquals(listOf("bar", "foo"), data)
data.add("zoo")
data.reverse()
assertEquals(listOf("zoo", "foo", "bar"), data)
}
@test fun reversed() {
val data = listOf("foo", "bar")
val rev = data.reversed()
assertEquals(listOf("bar", "foo"), rev)
}
@test fun reverseFunctionShouldReturnReversedCopyForList() {
val list: List<Int> = listOf(2, 3, 1)
expect(listOf(1, 3, 2)) { list.reversed() }
expect(listOf(2, 3, 1)) { list }
}
@test fun reverseFunctionShouldReturnReversedCopyForIterable() {
val iterable: Iterable<Int> = listOf(2, 3, 1)
expect(listOf(1, 3, 2)) { iterable.reversed() }
expect(listOf(2, 3, 1)) { iterable }
assertNotEquals(data, rev)
}