binaryio.swift

func read(handle: UnsafeMutablePointer<FILE>) throws -> Int {
    var buffer: [Int] = [Int](repeating: 0, count: 1)
    guard fread(&buffer, Int(MemoryLayout<Int>.size), 1, handle) == 1 else {
        throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
    }
    return buffer[0]
}

func write(value: Int, handle: UnsafeMutablePointer<FILE>) throws {
    do {
        guard fwrite([value], MemoryLayout<Int>.size, 1, handle) == 1 else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
        }
    } catch {
        throw error
    }
}

func read(handle: UnsafeMutablePointer<FILE>) throws -> String {
    do {
        let length: Int = try read(handle: handle)
        let buffer = UnsafeMutablePointer<unichar>.allocate(capacity: length)
        defer { buffer.deallocate(capacity: length) }
        guard fread(buffer, MemoryLayout<unichar>.size, length, handle) == length else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
        }
        guard let string = String(bytesNoCopy: buffer, length: MemoryLayout<unichar>.size * length, encoding: String.Encoding.utf16LittleEndian, freeWhenDone: false) else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "Failed to decode binary data to String."])
        }
        return string
    } catch {
        throw error
    }
}

func write(value: String, handle: UnsafeMutablePointer<FILE>) throws {
    do {
        let length = (value as NSString).length
        try write(value: length, handle: handle)
        let buffer = UnsafeMutablePointer<unichar>.allocate(capacity: length)
        defer { buffer.deallocate(capacity: length) }
        (value as NSString).getCharacters(buffer)
        guard fwrite(buffer, MemoryLayout<unichar>.size, length, handle) == length else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
        }
    } catch {
        throw error
    }
}

func readWithStringData(handle: UnsafeMutablePointer<FILE>) throws -> String {
    do {
        let length: Int = try read(handle: handle)
        let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: length)
        defer { buffer.deallocate(capacity: length) }
        guard fread(buffer, MemoryLayout<UInt8>.size, length, handle) == length else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
        }
        guard let string = String(bytesNoCopy: buffer, length: length, encoding: .utf8, freeWhenDone: false) else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "Failed to decode binary data to String."])
        }
        return string
    } catch {
        throw error
    }
}

func writeWithStringData(value: String, handle: UnsafeMutablePointer<FILE>) throws {
    do {
        guard let data = value.data(using: String.Encoding.utf8) else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "Can not decode string to binary."])
        }
        let length = Int((data as NSData).length)
        try write(value: length, handle: handle)
        guard fwrite((data as NSData).bytes, Int(1), length, handle) == length else {
            throw NSError(domain: "com.sonson.2tch", code: 0, userInfo: ["message": "An error occurred during writing to the handle (errno: \(errno))"])
        }
    } catch {
        throw error
    }
}