WriteBuffer
class WriteBuffer:MemoryBuffer
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public var offset = 0
public override init() {
// default memory with 32 bytes length
super.init(memory: malloc(32), capacity: 32, length: 0, freeWhenDone: true)
}
// make a read buffer for current memory
// reset self: realloc memory, reset capacity, offset
public func makeReadBufferAndReset() -> ReadBuffer {
// free when done
// means totaly make the memory's ownership to the new ReadBuffer
let buffer = ReadBuffer(memory: self.memory, length: self.offset, freeWhenDone: true)
self.memory = malloc(32)
self.capacity = 32
self.offset = 0
return buffer
}
public func readBufferNoCopy() -> ReadBuffer {
// frewWhenDon: false
// means: just for read
return ReadBuffer(memory: self.memory, length: self.offset, freeWhenDone: false)
}
// make data
override public func makeData() -> Data {
return Data(bytes: self.memory.assumingMemoryBound(to: UInt8.self), count: self.offset)
}
// reset offset to zero position
public func reset() {
self.offset = 0
}
// copy `data + offset` to `self.memory + self.offset`
public func write(_ data: UnsafeRawPointer, offset: Int = 0, length: Int) {
if self.offset + length > self.capacity {
self.capacity = self.offset + length + 256
if self.length == 0 {
self.memory = malloc(self.capacity)!
} else {
self.memory = realloc(self.memory, self.capacity)
}
}
memcpy(self.memory + self.offset, data + offset, length)
self.offset += length
self.length = self.offset
}
// write data to self.memory.advanced(by: offset)
// -[Data copyBytesTo:count:]
public func write(_ data: Data) {
let length = data.count
if self.offset + length > self.capacity {
self.capacity = self.offset + length + 256
if self.length == 0 {
self.memory = malloc(self.capacity)!
} else {
self.memory = realloc(self.memory, self.capacity)
}
}
data.copyBytes(to: self.memory.advanced(by: offset).assumingMemoryBound(to: UInt8.self), count: length)
self.offset += length
self.length = self.offset
}