87 lines
2.6 KiB
Swift
Executable File
87 lines
2.6 KiB
Swift
Executable File
// MIT License
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//
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// Copyright (c) 2017 Milen Dzhumerov
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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import Foundation
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class ByteBufferDecoder {
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private let bytes: UnsafePointer<UInt8>
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private var offset: Int
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private(set) var byteSwap: Bool
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init(bytes: UnsafePointer<UInt8>, byteSwap: Bool) {
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self.bytes = bytes
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self.offset = 0
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self.byteSwap = byteSwap
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}
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func advance<T: ByteSwappable & Equatable>() -> T {
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return advance {
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// Needs temporary `result` due to Swift's type inference
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let result: T = castBytes()
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return result.byte(swapped: byteSwap)
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}
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}
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func advanceByteSwappable<T: ByteSwappable & Equatable>(expect expectedValue: T) -> T {
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return advance {
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let memoryValue: T = castBytes()
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let swappedValue = expectedValue.byte(swapped: true)
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if memoryValue == expectedValue || memoryValue == swappedValue {
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byteSwap = (memoryValue == swappedValue)
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return expectedValue
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}
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return memoryValue
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}
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}
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fileprivate func castBytes<T>() -> T {
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return bytes.advanced(by: offset).withMemoryRebound(to: T.self, capacity: 1) {
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return $0.pointee
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}
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}
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private func advance<T>(_ body: () -> T) -> T {
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let value = body()
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offset += MemoryLayout<T>.size
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return value
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}
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}
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class ByteBufferEncoder {
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private(set) var bytes = Data()
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func encode<T>(_ value: T) {
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var mutableValue = value
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withUnsafeBytes(of: &mutableValue) { (pointer) in
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let valueBytes = Array(pointer[0..<pointer.count])
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bytes.append(contentsOf: valueBytes)
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}
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}
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func append(_ data: Data) {
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bytes.append(data)
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}
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}
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