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Fix Random.nextLong returning value out of range KT-47304

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Correctly zero-extend the lower Int part of the Long being produced
This commit is contained in:
Ilya Gorbunov
2021-09-29 06:50:41 +00:00
committed by Space
parent 43f64bc7b4
commit 193effc7c4
2 changed files with 10 additions and 8 deletions
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libraries/stdlib/src/kotlin/random/Random.kt
+2 -2
View File
@@ -1,5 +1,5 @@
/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
@@ -135,7 +135,7 @@ public abstract class Random {
nextInt().toLong() and 0xFFFF_FFFF
else -> {
val bitCount = fastLog2(nHigh)
nextBits(bitCount).toLong().shl(32) + nextInt()
nextBits(bitCount).toLong().shl(32) + (nextInt().toLong() and 0xFFFF_FFFF)
}
}
} else {
libraries/stdlib/test/random/RandomTest.kt
+8 -6
View File
@@ -1,5 +1,5 @@
/*
* Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
@@ -229,7 +229,7 @@ abstract class RandomSmokeTest {
assertEquals(0L, subject.nextLong(1))
}
for (bound in listOf(2, 23, 32, 0x1_0000_0000, 0x4000_0000_0000_0000, Long.MAX_VALUE)) {
for (bound in listOf(2, 23, 32, 0x1_0000_0000, 0x4_0000_0000, 0x4000_0000_0000_0000, Long.MAX_VALUE)) {
repeat(1000) {
val x = subject.nextLong(bound)
if (x !in 0L until bound)
@@ -246,7 +246,7 @@ abstract class RandomSmokeTest {
assertEquals(0uL, subject.nextULong(1uL))
}
for (bound in listOf(2uL, 23uL, 32uL, 0x1_0000_0000uL, 0x8000_0000_0000_000uL, ULong.MAX_VALUE)) {
for (bound in listOf(2uL, 23uL, 32uL, 0x1_0000_0000uL, 0x4_0000_0000uL, 0x8000_0000_0000_000uL, ULong.MAX_VALUE)) {
repeat(1000) {
val x = subject.nextULong(bound)
if (x !in 0uL until bound) {
@@ -267,8 +267,8 @@ abstract class RandomSmokeTest {
assertEquals(n, subject.nextLong(n, n + 1))
}
for ((from, until) in listOf((0L to 32L), (-1L to 5L), (0L to 0x1_0000_0000),
(0L to Long.MAX_VALUE), (-1L to Long.MAX_VALUE), (Long.MIN_VALUE to Long.MAX_VALUE))) {
for ((from, until) in listOf((0L to 32L), (-1L to 5L), (0L to 0x1_0000_0000), (-0x10L to 0x3_FFFF_FFF0L),
(0L to Long.MAX_VALUE), (-1L to Long.MAX_VALUE), (Long.MIN_VALUE to Long.MAX_VALUE))) {
repeat(1000) {
val x = subject.nextLong(from, until)
if (x !in from until until)
@@ -291,6 +291,7 @@ abstract class RandomSmokeTest {
(0uL to 32uL),
(1uL to 6uL),
(0uL to 0x1_0000_0000.toULong()),
(0x10uL to 0x4_0000_0010.toULong()),
(0uL to ULong.MAX_VALUE)
)) {
repeat(1000) {
@@ -314,7 +315,7 @@ abstract class RandomSmokeTest {
assertEquals(n, subject.nextLong(n..n))
}
for (range in listOf((0L until 2L), (-1L until 5L), (0L until 32L), (0L until Long.MAX_VALUE),
for (range in listOf((0L until 2L), (-1L until 5L), (0L until 32L), (0L until 1L.shl(33)), (0L until Long.MAX_VALUE),
(0L..Long.MAX_VALUE), (Long.MIN_VALUE..0L), (Long.MIN_VALUE..Long.MAX_VALUE))) {
repeat(1000) {
val x = subject.nextLong(range)
@@ -339,6 +340,7 @@ abstract class RandomSmokeTest {
(0uL..1uL),
(1uL..5uL),
(0uL..31uL),
(0uL until 0x4_0000_0000uL),
(0uL..(ULong.MAX_VALUE - 1uL)),
(1uL..ULong.MAX_VALUE),
(0uL..ULong.MAX_VALUE)