Thanks to visit codestin.com
Credit goes to github.com

Skip to content

[Swift] Moves capacity from storage to struct #8650

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
mustiikhalil merged 1 commit into from
Jul 29, 2025
Merged

[Swift] Moves capacity from storage to struct #8650

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
45 changes: 26 additions & 19 deletions swift/Sources/FlatBuffers/ByteBuffer.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,11 +40,11 @@ public struct ByteBuffer {

/// This storage doesn't own the memory, therefore, we won't deallocate on deinit.
private let isOwned: Bool
/// Capacity of UInt8 the buffer can hold
private let capacity: Int
/// Retained blob of data that requires the storage to retain a pointer to.
@usableFromInline
var retainedBlob: Blob
/// Capacity of UInt8 the buffer can hold
var capacity: Int

@usableFromInline
init(count: Int) {
Expand Down Expand Up @@ -179,11 +179,11 @@ public struct ByteBuffer {
/// The size of the elements written to the buffer + their paddings
private var _readerIndex: Int = 0
/// Reader is the position of the current Writer Index (capacity - size)
public var reader: Int { _storage.capacity &- _readerIndex }
public var reader: Int { capacity &- _readerIndex }
/// Current size of the buffer
public var size: UOffset { UOffset(_readerIndex) }
/// Current capacity for the buffer
public var capacity: Int { _storage.capacity }
public let capacity: Int

/// Constructor that creates a Flatbuffer object from an InternalByteBuffer
/// - Parameter
Expand All @@ -194,6 +194,7 @@ public struct ByteBuffer {
blob: .byteBuffer(byteBuffer),
capacity: byteBuffer.capacity)
_readerIndex = Int(byteBuffer.size)
self.capacity = byteBuffer.capacity
}

/// Constructor that creates a Flatbuffer from unsafe memory region by copying
Expand All @@ -209,7 +210,8 @@ public struct ByteBuffer {
{
_storage = Storage(count: capacity)
_storage.copy(from: memory, count: capacity)
_readerIndex = _storage.capacity
_readerIndex = capacity
self.capacity = capacity
}

/// Constructor that creates a Flatbuffer object from a UInt8
Expand All @@ -218,7 +220,8 @@ public struct ByteBuffer {
@inline(__always)
public init(bytes: [UInt8]) {
_storage = Storage(blob: .array(bytes), capacity: bytes.count)
_readerIndex = _storage.capacity
_readerIndex = bytes.count
capacity = bytes.count
}

#if !os(WASI)
Expand All @@ -228,7 +231,8 @@ public struct ByteBuffer {
@inline(__always)
public init(data: Data) {
_storage = Storage(blob: .data(data), capacity: data.count)
_readerIndex = _storage.capacity
_readerIndex = data.count
capacity = data.count
}

/// Constructor that creates a Flatbuffer object from a ContiguousBytes
Expand All @@ -241,7 +245,8 @@ public struct ByteBuffer {
count: Int)
{
_storage = Storage(blob: .bytes(contiguousBytes), capacity: count)
_readerIndex = _storage.capacity
_readerIndex = count
self.capacity = count
}
#endif

Expand All @@ -259,7 +264,8 @@ public struct ByteBuffer {
_storage = Storage(
blob: .pointer(memory),
capacity: capacity)
_readerIndex = _storage.capacity
_readerIndex = capacity
self.capacity = capacity
}

/// Creates a copy of the existing flatbuffer, by copying it to a different memory.
Expand All @@ -275,6 +281,7 @@ public struct ByteBuffer {
{
_storage = Storage(blob: blob, capacity: count)
_readerIndex = removeBytes
capacity = count
}

/// Write stores an object into the buffer directly or indirectly.
Expand All @@ -289,11 +296,11 @@ public struct ByteBuffer {
func write<T>(value: T, index: Int, direct: Bool = false) {
var index = index
if !direct {
index = _storage.capacity &- index
index = capacity &- index
}
assert(index < _storage.capacity, "Write index is out of writing bound")
assert(index < capacity, "Write index is out of writing bound")
assert(index >= 0, "Writer index should be above zero")
withUnsafePointer(to: value) { ptr in
_ = withUnsafePointer(to: value) { ptr in
_storage.withUnsafeRawPointer {
memcpy(
$0.advanced(by: index),
Expand Down Expand Up @@ -325,7 +332,7 @@ public struct ByteBuffer {
count: Int) -> [T]
{
assert(
index + count <= _storage.capacity,
index + count <= capacity,
"Reading out of bounds is illegal")

return _storage.readWithUnsafeRawPointer(position: index) {
Expand All @@ -348,7 +355,7 @@ public struct ByteBuffer {
body: (UnsafeRawBufferPointer) throws -> T) rethrows -> T
{
assert(
index + count <= _storage.capacity,
index + count <= capacity,
"Reading out of bounds is illegal")
return try _storage.readWithUnsafeRawPointer(position: index) {
try body(UnsafeRawBufferPointer(start: $0, count: count))
Expand All @@ -368,7 +375,7 @@ public struct ByteBuffer {
type: String.Encoding = .utf8) -> String?
{
assert(
index + count <= _storage.capacity,
index + count <= capacity,
"Reading out of bounds is illegal")
return _storage.readWithUnsafeRawPointer(position: index) {
let buf = UnsafeBufferPointer(
Expand All @@ -390,7 +397,7 @@ public struct ByteBuffer {
count: Int) -> String?
{
assert(
index + count <= _storage.capacity,
index + count <= capacity,
"Reading out of bounds is illegal")
return _storage.readWithUnsafeRawPointer(position: index) {
String(cString: $0.bindMemory(to: UInt8.self, capacity: count))
Expand All @@ -404,11 +411,11 @@ public struct ByteBuffer {
public func duplicate(removing removeBytes: Int = 0) -> ByteBuffer {
assert(removeBytes > 0, "Can NOT remove negative bytes")
assert(
removeBytes < _storage.capacity,
removeBytes < capacity,
"Can NOT remove more bytes than the ones allocated")
return ByteBuffer(
blob: _storage.retainedBlob,
count: _storage.capacity,
count: capacity,
removing: _readerIndex &- removeBytes)
}

Expand Down Expand Up @@ -456,7 +463,7 @@ extension ByteBuffer: CustomDebugStringConvertible {
public var debugDescription: String {
"""
buffer located at: \(_storage.retainedBlob),
with capacity of \(_storage.capacity),
with capacity of \(capacity),
{ writtenSize: \(_readerIndex), readerSize: \(reader),
size: \(size) }
"""
Expand Down
4 changes: 2 additions & 2 deletions swift/Sources/FlatBuffers/Mutable.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ extension Mutable where Self == Table {
/// - index: index of the Element
public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
guard index != 0 else { return false }
return mutate(value: value, o: index + position)
return mutate(value: value, o: index &+ position)
}

/// Directly mutates the element by calling mutate
Expand All @@ -70,7 +70,7 @@ extension Mutable where Self == Struct {
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
mutate(value: value, o: index + position)
mutate(value: value, o: index &+ position)
}

/// Directly mutates the element by calling mutate
Expand Down
2 changes: 1 addition & 1 deletion swift/Sources/FlatBuffers/Struct.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ public struct Struct {
/// - o: Current offset of the data
/// - Returns: Data of Type T that conforms to type Scalar
public func readBuffer<T: Scalar>(of type: T.Type, at o: Int32) -> T {
let r = bb.read(def: T.self, position: Int(o + position))
let r = bb.read(def: T.self, position: Int(o &+ position))
return r
}
}
4 changes: 2 additions & 2 deletions swift/Sources/FlatBuffers/Table.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ public struct Table {
public func vector(at o: Int32) -> Int32 {
var o = o
o &+= position
return o &+ bb.read(def: Int32.self, position: Int(o)) + 4
return o &+ bb.read(def: Int32.self, position: Int(o)) &+ 4
}

/// Reading an indirect offset of a table.
Expand All @@ -176,7 +176,7 @@ public struct Table {
/// - fbb: ByteBuffer
/// - Returns: table offset
static public func indirect(_ o: Int32, _ fbb: ByteBuffer) -> Int32 {
o + fbb.read(def: Int32.self, position: Int(o))
o &+ fbb.read(def: Int32.self, position: Int(o))
}

/// Gets a vtable value according to an table Offset and a field offset
Expand Down
54 changes: 32 additions & 22 deletions swift/Sources/FlatBuffers/_InternalByteBuffer.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,15 +31,12 @@ struct _InternalByteBuffer {
final class Storage {
/// pointer to the start of the buffer object in memory
private(set) var memory: UnsafeMutableRawPointer
/// Capacity of UInt8 the buffer can hold
private(set) var capacity: Int

@usableFromInline
init(count: Int, alignment: Int) {
memory = UnsafeMutableRawPointer.allocate(
byteCount: count,
alignment: alignment)
capacity = count
}

deinit {
Expand All @@ -54,15 +51,12 @@ struct _InternalByteBuffer {
/// Reallocates the buffer incase the object to be written doesnt fit in the current buffer
/// - Parameter size: Size of the current object
@usableFromInline
func reallocate(_ size: Int, writerSize: Int, alignment: Int) {
let currentWritingIndex = capacity &- writerSize
while capacity <= writerSize &+ size {
capacity = capacity << 1
}

/// solution take from Apple-NIO
capacity = capacity.convertToPowerofTwo

func reallocate(
capacity: Int,
writerSize: Int,
currentWritingIndex: Int,
alignment: Int
) {
let newData = UnsafeMutableRawPointer.allocate(
byteCount: capacity,
alignment: alignment)
Expand All @@ -84,7 +78,7 @@ struct _InternalByteBuffer {
/// Alignment of the current memory being written to the buffer
var alignment = 1
/// Current Index which is being used to write to the buffer, it is written from the end to the start of the buffer
var writerIndex: Int { _storage.capacity &- _writerSize }
var writerIndex: Int { capacity &- _writerSize }

/// Reader is the position of the current Writer Index (capacity - size)
public var reader: Int { writerIndex }
Expand All @@ -94,14 +88,15 @@ struct _InternalByteBuffer {
@usableFromInline
var memory: UnsafeMutableRawPointer { _storage.memory }
/// Current capacity for the buffer
public var capacity: Int { _storage.capacity }
public private(set) var capacity: Int

/// Constructor that creates a Flatbuffer instance with a size
/// - Parameter:
/// - size: Length of the buffer
/// - allowReadingUnalignedBuffers: allow reading from unaligned buffer
init(initialSize size: Int) {
initialSize = size.convertToPowerofTwo
capacity = initialSize
_storage = Storage(count: initialSize, alignment: alignment)
_storage.initialize(for: initialSize)
}
Expand Down Expand Up @@ -246,11 +241,11 @@ struct _InternalByteBuffer {
func write<T>(value: T, index: Int, direct: Bool = false) {
var index = index
if !direct {
index = _storage.capacity &- index
index = capacity &- index
}
assert(index < _storage.capacity, "Write index is out of writing bound")
assert(index < capacity, "Write index is out of writing bound")
assert(index >= 0, "Writer index should be above zero")
withUnsafePointer(to: value) {
_ = withUnsafePointer(to: value) {
memcpy(
_storage.memory.advanced(by: index),
$0,
Expand All @@ -262,10 +257,24 @@ struct _InternalByteBuffer {
/// - Parameter size: size of object
@discardableResult
@usableFromInline
@inline(__always)
mutating func ensureSpace(size: Int) -> Int {
if size &+ _writerSize > _storage.capacity {
_storage.reallocate(size, writerSize: _writerSize, alignment: alignment)
let expectedWriterIndex = size &+ _writerSize
if expectedWriterIndex > capacity {

let currentWritingIndex = capacity &- _writerSize
while capacity <= expectedWriterIndex {
capacity = capacity << 1
}

/// solution take from Apple-NIO
capacity = capacity.convertToPowerofTwo


_storage.reallocate(
capacity: capacity,
writerSize: _writerSize,
currentWritingIndex: currentWritingIndex,
alignment: alignment)
}
assert(size < FlatBufferMaxSize, "Buffer can't grow beyond 2 Gigabytes")
return size
Expand Down Expand Up @@ -295,8 +304,9 @@ struct _InternalByteBuffer {
_writerSize = 0
alignment = 1
if keepingCapacity {
_storage.initialize(for: _storage.capacity)
_storage.initialize(for: capacity)
} else {
capacity = initialSize
_storage = Storage(count: initialSize, alignment: alignment)
}
}
Expand Down Expand Up @@ -358,7 +368,7 @@ extension _InternalByteBuffer: CustomDebugStringConvertible {

public var debugDescription: String {
"""
buffer located at: \(_storage.memory), with capacity of \(_storage.capacity)
buffer located at: \(_storage.memory), with capacity of \(capacity)
{ writerSize: \(_writerSize), readerSize: \(reader), writerIndex: \(
writerIndex) }
"""
Expand Down
Loading
Loading