CryptoSwift/Sources/CryptoSwift/ZeroPadding.swift

//
//  ZeroPadding.swift
//  CryptoSwift
//
//  Created by Marcin Krzyzanowski on 13/06/16.
//  Copyright © 2016 Marcin Krzyzanowski. All rights reserved.
//

/// All the bytes that are required to be padded are padded with zero.
/// Zero padding may not be reversible if the original file ends with one or more zero bytes.
public struct ZeroPadding: Padding {
    public init() {
    }

    public func add(to bytes: Array<UInt8>, blockSize:Int) -> Array<UInt8> {
        let paddingCount = blockSize - (bytes.count % blockSize)
        if paddingCount > 0 {
            return bytes + Array<UInt8>(repeating: 0, count: paddingCount)
        }
        return bytes
    }

    public func remove(from bytes: Array<UInt8>, blockSize:Int?) -> Array<UInt8> {
        for (idx, value) in bytes.reversed().enumerated() {
            if value != 0 {
                return Array(bytes[0..<bytes.count - idx])
            }
        }
        return bytes;

    }
}