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stdlib: Don't check for overflows when adding 1 to Array.count

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That addition can not possibly overflow. If Array.count would be Int max, the allocation of the array buffer would have failed way before.
This commit is contained in:
Erik Eckstein
2021-11-23 18:26:29 +01:00
parent 2a9c148e7a
commit 97424b76f4
3 changed files with 16 additions and 16 deletions
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12
stdlib/public/core/ContiguousArray.swift
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@@ -724,7 +724,7 @@ extension ContiguousArray: RangeReplaceableCollection {
@inline(never)
@inlinable // @specializable
internal mutating func _copyToNewBuffer(oldCount: Int) {
let newCount = oldCount + 1
let newCount = oldCount &+ 1
var newBuffer = _buffer._forceCreateUniqueMutableBuffer(
countForNewBuffer: oldCount, minNewCapacity: newCount)
_buffer._arrayOutOfPlaceUpdate(
@@ -736,7 +736,7 @@ extension ContiguousArray: RangeReplaceableCollection {
internal mutating func _makeUniqueAndReserveCapacityIfNotUnique() {
if _slowPath(!_buffer.beginCOWMutation()) {
_createNewBuffer(bufferIsUnique: false,
minimumCapacity: count + 1,
minimumCapacity: count &+ 1,
growForAppend: true)
}
}
@@ -756,9 +756,9 @@ extension ContiguousArray: RangeReplaceableCollection {
let capacity = _buffer.mutableCapacity
_internalInvariant(capacity == 0 || _buffer.isMutableAndUniquelyReferenced())
if _slowPath(oldCount + 1 > capacity) {
if _slowPath(oldCount &+ 1 > capacity) {
_createNewBuffer(bufferIsUnique: capacity > 0,
minimumCapacity: oldCount + 1,
minimumCapacity: oldCount &+ 1,
growForAppend: true)
}
}
@@ -770,9 +770,9 @@ extension ContiguousArray: RangeReplaceableCollection {
newElement: __owned Element
) {
_internalInvariant(_buffer.isMutableAndUniquelyReferenced())
_internalInvariant(_buffer.mutableCapacity >= _buffer.mutableCount + 1)
_internalInvariant(_buffer.mutableCapacity >= _buffer.mutableCount &+ 1)
_buffer.mutableCount = oldCount + 1
_buffer.mutableCount = oldCount &+ 1
(_buffer.mutableFirstElementAddress + oldCount).initialize(to: newElement)
}