BigfootDev/flatbuffers-bigfoot
1
0
Fork 0
forked from BigfootDev/flatbuffers
Code Pull Requests Activity

[Swift] Rebuild the way swift handles structs from scratch (#6326)

Browse Source 
* Rebuild the way swift handles structs from scratch

* Updates docs, and sample binary

* Replaces InMemory to Mutable

* Migrates docs from inmemory

* use inline for some functions

* Renamed Mutable objects

* Updates documentation
This commit is contained in:
mustiikhalil
2020-12-18 01:55:32 +03:00
committed by GitHub
parent 05192553f4
commit 4e79d129cb
21 changed files with 1051 additions and 720 deletions
Download Patch File Download Diff File Expand all files Collapse all files

133
swift/Sources/FlatBuffers/FlatBufferBuilder.swift
View File

@@ -20,11 +20,11 @@ public struct FlatBufferBuilder {
/// Storage for the Vtables used in the buffer are stored in here, so they would be written later in EndTable
@usableFromInline internal var _vtableStorage = VTableStorage()
/// Flatbuffer data will be written into
@usableFromInline internal var _bb: ByteBuffer
/// Reference Vtables that were already written to the buffer
private var _vtables: [UOffset] = []
/// Flatbuffer data will be written into
private var _bb: ByteBuffer
/// A check if the buffer is being written into by a different table
private var isNested = false
/// Dictonary that stores a map of all the strings that were written to the buffer
@@ -227,7 +227,7 @@ public struct FlatBufferBuilder {
/// Changes the minimuim alignment of the buffer
/// - Parameter size: size of the current alignment
@usableFromInline
@inline(__always)
mutating internal func minAlignment(size: Int) {
if size > _minAlignment {
_minAlignment = size
@@ -238,7 +238,7 @@ public struct FlatBufferBuilder {
/// - Parameters:
/// - bufSize: Current size of the buffer + the offset of the object to be written
/// - elementSize: Element size
@usableFromInline
@inline(__always)
mutating internal func padding(bufSize: UInt32, elementSize: UInt32) -> UInt32 {
((~bufSize) &+ 1) & (elementSize - 1)
}
@@ -282,7 +282,7 @@ public struct FlatBufferBuilder {
_vtableStorage.add(loc: FieldLoc(offset: offset, position: position))
}
// MARK: - Vectors
// MARK: - Inserting Vectors
/// Starts a vector of length and Element size
mutating public func startVector(_ len: Int, elementSize: Int) {
@@ -296,10 +296,10 @@ public struct FlatBufferBuilder {
///
/// The current function will fatalError if startVector is called before serializing the vector
/// - Parameter len: Length of the buffer
mutating public func endVector(len: Int) -> UOffset {
mutating public func endVector(len: Int) -> Offset<UOffset> {
assert(isNested, "Calling endVector without calling startVector")
isNested = false
return push(element: Int32(len))
return Offset(offset: push(element: Int32(len)))
}
/// Creates a vector of type Scalar in the buffer
@@ -317,7 +317,7 @@ public struct FlatBufferBuilder {
let size = size
startVector(size, elementSize: MemoryLayout<T>.size)
_bb.push(elements: elements)
return Offset(offset: endVector(len: size))
return endVector(len: size)
}
/// Creates a vector of type Enums in the buffer
@@ -337,7 +337,7 @@ public struct FlatBufferBuilder {
for e in elements.reversed() {
_bb.push(value: e.value, len: T.byteSize)
}
return Offset(offset: endVector(len: size))
return endVector(len: size)
}
/// Creates a vector of type Offsets in the buffer
@@ -356,7 +356,7 @@ public struct FlatBufferBuilder {
for o in offsets.reversed() {
push(element: o)
}
return Offset(offset: endVector(len: len))
return endVector(len: len)
}
/// Creates a vector of Strings
@@ -370,101 +370,47 @@ public struct FlatBufferBuilder {
return createVector(ofOffsets: offsets)
}
/// Creates a vector of Flatbuffer structs.
///
/// The function takes a Type to know what size it is, and alignment
/// - Parameters:
/// - structs: An array of UnsafeMutableRawPointer
/// - type: Type of the struct being written
/// - returns: Offset of the vector
@available(
*,
deprecated,
message: "0.9.0 will be removing the following method. Regenerate the code")
mutating public func createVector<T: Readable>(
structs: [UnsafeMutableRawPointer],
type: T.Type) -> Offset<UOffset>
{
startVector(structs.count &* T.size, elementSize: T.alignment)
/// Creates a vector of `Native swift structs` which were padded to flatbuffers standards
/// - Parameter structs: A vector of structs
/// - Returns: offset of the vector
mutating public func createVector<T: NativeStruct>(ofStructs structs: [T]) -> Offset<UOffset> {
startVector(structs.count * MemoryLayout<T>.size, elementSize: MemoryLayout<T>.alignment)
for i in structs.reversed() {
create(struct: i, type: T.self)
_ = create(struct: i)
}
return Offset(offset: endVector(len: structs.count))
}
/// Starts a vector of struct that considers the size and alignment of the struct
/// - Parameters:
/// - count: number of elements to be written
/// - size: size of struct
/// - alignment: alignment of the struct
mutating public func startVectorOfStructs(count: Int, size: Int, alignment: Int) {
startVector(count &* size, elementSize: alignment)
}
/// Ends the vector of structs and writtens the current offset
/// - Parameter count: number of written elements
/// - Returns: Offset of type UOffset
mutating public func endVectorOfStructs(count: Int) -> Offset<UOffset> {
Offset<UOffset>(offset: endVector(len: count))
return endVector(len: structs.count)
}
// MARK: - Inserting Structs
/// Writes a Flatbuffer struct into the buffer
/// Fills the buffer with a native struct that's build and padded according to flatbuffers standards
/// - Parameters:
/// - s: Flatbuffer struct
/// - type: Type of the element to be serialized
/// - returns: Offset of the Object
@available(
*,
deprecated,
message: "0.9.0 will be removing the following method. Regenerate the code")
/// - s: `Native swift` struct to insert
/// - position: The predefined position of the object
/// - Returns: offset of written struct
@discardableResult
mutating public func create<T: Readable>(
struct s: UnsafeMutableRawPointer,
type: T.Type) -> Offset<UOffset>
mutating public func create<T: NativeStruct>(
struct s: T, position: VOffset) -> Offset<UOffset>
{
let size = T.size
preAlign(len: size, alignment: T.alignment)
let offset = create(struct: s)
_vtableStorage.add(loc: FieldLoc(offset: _bb.size, position: VOffset(position)))
return offset
}
/// Fills the buffer with a native struct that's build and padded according to flatbuffers standards
/// - Parameters:
/// - s: `Native swift` struct to insert
/// - Returns: offset of written struct
@discardableResult
mutating public func create<T: NativeStruct>(
struct s: T) -> Offset<UOffset>
{
let size = MemoryLayout<T>.size
preAlign(len: size, alignment: MemoryLayout<T>.alignment)
_bb.push(struct: s, size: size)
return Offset(offset: _bb.size)
}
/// prepares the ByteBuffer to receive a struct of size and alignment
/// - Parameters:
/// - size: size of written struct
/// - alignment: alignment of written struct
mutating public func createStructOf(size: Int, alignment: Int) {
preAlign(len: size, alignment: alignment)
_bb.prepareBufferToReceiveStruct(of: size)
}
/// Adds scalars front to back instead of the default behavior of the normal add
/// - Parameters:
/// - v: element of type Scalar
/// - postion: position relative to the `writerIndex`
mutating public func reverseAdd<T: Scalar>(v: T, postion: Int) {
_bb.reversePush(
value: v,
position: postion,
len: MemoryLayout<T>.size)
}
/// Ends the struct and returns the current buffer size
/// - Returns: Offset of type UOffset
@discardableResult
public func endStruct() -> Offset<UOffset> {
Offset(offset: _bb.size)
}
/// Adds the offset of a struct into the vTable
///
/// The function fatalErrors if we pass an offset that is out of range
/// - Parameter o: offset
mutating public func add(structOffset o: VOffset) {
_vtableStorage.add(loc: FieldLoc(offset: _bb.size, position: VOffset(o)))
}
// MARK: - Inserting Strings
/// Insets a string into the buffer using UTF8
@@ -596,6 +542,7 @@ extension FlatBufferBuilder: CustomDebugStringConvertible {
/// Builds a buffer with byte count of fieldloc.size * count of field numbers
/// - Parameter count: number of fields to be written
@inline(__always)
func start(count: Int) {
assert(count >= 0, "number of fields should NOT be negative")
let capacity = count &* size
@@ -621,6 +568,7 @@ extension FlatBufferBuilder: CustomDebugStringConvertible {
/// Ensure that the buffer has enough space instead of recreating the buffer each time.
/// - Parameter space: space required for the new vtable
@inline(__always)
func ensure(space: Int) {
guard space &+ writtenIndex > capacity else { return }
memory.deallocate()
@@ -631,6 +579,7 @@ extension FlatBufferBuilder: CustomDebugStringConvertible {
/// Loads an object of type `FieldLoc` from buffer memory
/// - Parameter index: index of element
/// - Returns: a FieldLoc at index
@inline(__always)
func load(at index: Int) -> FieldLoc {
memory.load(fromByteOffset: index, as: FieldLoc.self)
}