secretive/SecretAgentKit/OpenSSHReader.swift

import Foundation

public class OpenSSHReader {

    var remaining: Data

    public init(data: Data) {
        remaining = Data(data)
    }

    public func readNextChunk() throws -> Data {
        let lengthRange = 0..<(UInt32.bitWidth/8)
        let lengthChunk = remaining[lengthRange]
        remaining.removeSubrange(lengthRange)
        let littleEndianLength = lengthChunk.withUnsafeBytes { pointer in
            return pointer.load(as: UInt32.self)
        }
        let length = Int(littleEndianLength.bigEndian)
        let dataRange = 0..<length
        let ret = Data(remaining[dataRange])
        remaining.removeSubrange(dataRange)
        return ret
    }

}