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Remove expensive availability checks from Data replaceSubrange #1571

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Merged
merged 2 commits into from
Nov 4, 2025
Merged

Remove expensive availability checks from Data replaceSubrange #1571

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3c99826
(163828996) Remove expensive availability checks from Data replaceSub…
jmschonfeld Nov 1, 2025
8b6149e
Cleanup range arithmetic
jmschonfeld Nov 3, 2025
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40 changes: 10 additions & 30 deletions Sources/FoundationEssentials/Data/Representations/Data+InlineSlice.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -172,24 +172,12 @@ extension Data {
mutating func append(contentsOf buffer: UnsafeRawBufferPointer) {
assert(endIndex + buffer.count < HalfInt.max)
ensureUniqueReference()
let upperbound = storage.length + storage._offset
#if FOUNDATION_FRAMEWORK
if #available(macOS 14, iOS 17, watchOS 10, tvOS 17, *) {
storage.replaceBytes(
in: range.upperBound ..< upperbound,
with: buffer.baseAddress,
length: buffer.count)
} else {
storage.replaceBytes(
in: NSRange(
location: range.upperBound,
length: storage.length - (range.upperBound - storage._offset)),
with: buffer.baseAddress,
length: buffer.count)
}
#else
storage.replaceBytes(in: range.upperBound ..< upperbound, with: buffer.baseAddress, length: buffer.count)
#endif
storage.replaceBytes(
in: (
location: range.upperBound,
length: storage.length - (range.upperBound - storage._offset)),
with: buffer.baseAddress,
length: buffer.count)
slice = slice.lowerBound..<HalfInt(Int(slice.upperBound) + buffer.count)
}

Expand Down Expand Up @@ -231,18 +219,10 @@ extension Data {

ensureUniqueReference()
let upper = range.upperBound
#if FOUNDATION_FRAMEWORK
if #available(macOS 14, iOS 17, watchOS 10, tvOS 17, *) {
storage.replaceBytes(in: subrange, with: bytes, length: cnt)
} else {
let nsRange = NSRange(
location: subrange.lowerBound,
length: subrange.upperBound - subrange.lowerBound)
storage.replaceBytes(in: nsRange, with: bytes, length: cnt)
}
#else
storage.replaceBytes(in: subrange, with: bytes, length: cnt)
#endif
let nsRange = (
location: subrange.lowerBound,
length: subrange.upperBound - subrange.lowerBound)
storage.replaceBytes(in: nsRange, with: bytes, length: cnt)
let resultingUpper = upper - (subrange.upperBound - subrange.lowerBound) + cnt
slice = slice.lowerBound..<HalfInt(resultingUpper)
}
Expand Down
39 changes: 10 additions & 29 deletions Sources/FoundationEssentials/Data/Representations/Data+LargeSlice.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -160,23 +160,12 @@ extension Data {
mutating func append(contentsOf buffer: UnsafeRawBufferPointer) {
ensureUniqueReference()
let upperbound = storage.length + storage._offset
#if FOUNDATION_FRAMEWORK
if #available(macOS 14, iOS 17, watchOS 10, tvOS 17, *) {
storage.replaceBytes(
in: range.upperBound ..< upperbound,
with: buffer.baseAddress,
length: buffer.count)
} else {
storage.replaceBytes(
in: NSRange(
location: range.upperBound,
length: storage.length - (range.upperBound - storage._offset)),
with: buffer.baseAddress,
length: buffer.count)
}
#else
storage.replaceBytes(in: range.upperBound ..< upperbound, with: buffer.baseAddress, length: buffer.count)
#endif
storage.replaceBytes(
in: (
location: range.upperBound,
length: storage.length - (range.upperBound - storage._offset)),
with: buffer.baseAddress,
length: buffer.count)
slice.range = slice.range.lowerBound..<slice.range.upperBound + buffer.count
}

Expand Down Expand Up @@ -214,18 +203,10 @@ extension Data {

ensureUniqueReference()
let upper = range.upperBound
#if FOUNDATION_FRAMEWORK
if #available(macOS 14, iOS 17, watchOS 10, tvOS 17, *) {
storage.replaceBytes(in: subrange, with: bytes, length: cnt)
} else {
let nsRange = NSRange(
location: subrange.lowerBound,
length: subrange.upperBound - subrange.lowerBound)
storage.replaceBytes(in: nsRange, with: bytes, length: cnt)
}
#else
storage.replaceBytes(in: subrange, with: bytes, length: cnt)
#endif
let nsRange = (
location: subrange.lowerBound,
length: subrange.upperBound - subrange.lowerBound)
storage.replaceBytes(in: nsRange, with: bytes, length: cnt)
let resultingUpper = upper - (subrange.upperBound - subrange.lowerBound) + cnt
slice.range = slice.range.lowerBound..<resultingUpper
}
Expand Down
24 changes: 17 additions & 7 deletions Sources/FoundationEssentials/Data/Representations/DataStorage.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -330,14 +330,24 @@ internal final class __DataStorage : @unchecked Sendable {
UnsafeMutableRawBufferPointer(start: pointer, count: range.upperBound - range.lowerBound).copyMemory(from: offsetPointer)
}

#if FOUNDATION_FRAMEWORK
// This was an ABI entrypoint added in macOS 14-aligned releases in an attempt to work around the original declaration using NSRange instead of Range<Int>
// Using this entrypoint from existing inlinable code required an availability check, and that check has proved to be extremely expensive
// This entrypoint is left to preserve ABI compatibility, but inlinable code has since switched back to calling the original entrypoint using a tuple that is layout-compatible with NSRange
@available(macOS 14, iOS 17, tvOS 17, watchOS 10, *)
#endif
@usableFromInline // This is not @inlinable as it is a non-trivial, non-generic function.
@usableFromInline
func replaceBytes(in range_: Range<Int>, with replacementBytes: UnsafeRawPointer?, length replacementLength: Int) {
let range = range_.lowerBound - _offset ..< range_.upperBound - _offset
// Call through to the main implementation
self.replaceBytes(in: (range_.lowerBound, range_.upperBound &- range_.lowerBound), with: replacementBytes, length: replacementLength)
}

// This ABI entrypoint was original written using NSRange instead of Range<Int>. The ABI contract of this function must continue to accept NSRange values from code inlined into callers
// To avoid using the real NSRange type at the source level, we use a tuple that is layout-compatible with NSRange instead and use @_silgen_name to preserve the original symbol name that includes "NSRange"
@usableFromInline
@_silgen_name("$s10Foundation13__DataStorageC12replaceBytes2in4with6lengthySo8_NSRangeV_SVSgSitF")
internal func replaceBytes(in range_: (location: Int, length: Int), with replacementBytes: UnsafeRawPointer?, length replacementLength: Int) {
let range = (location: range_.location - _offset, length: range_.length)
let currentLength = _length
let resultingLength = currentLength - (range.upperBound - range.lowerBound) + replacementLength
let resultingLength = currentLength - range.length + replacementLength
let shift = resultingLength - currentLength
let mutableBytes: UnsafeMutableRawPointer
if resultingLength > currentLength {
Expand All @@ -348,8 +358,8 @@ internal final class __DataStorage : @unchecked Sendable {
}
mutableBytes = _bytes!
/* shift the trailing bytes */
let start = range.lowerBound
let length = range.upperBound - range.lowerBound
let start = range.location
let length = range.length
if shift != 0 {
memmove(mutableBytes + start + replacementLength, mutableBytes + start + length, currentLength - start - length)
}
Expand Down