powershell-pulp

2.1.0

lib/Helpers.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace PowershellPulp
{
    public class Helpers
    {
        /// <summary>
        /// This helper function parses an integer size from the reader using the ASN.1 format
        /// </summary>
        /// <param name="rd"></param>
        /// <returns></returns>
        public static int DecodeIntegerSize(System.IO.BinaryReader rd)
        {
            byte byteValue;
            int count;
 
            byteValue = rd.ReadByte();
            if (byteValue != 0x02) // indicates an ASN.1 integer value follows
                return 0;
 
            byteValue = rd.ReadByte();
            if (byteValue == 0x81)
            {
                count = rd.ReadByte(); // data size is the following byte
            }
            else if (byteValue == 0x82)
            {
                byte hi = rd.ReadByte(); // data size in next 2 bytes
                byte lo = rd.ReadByte();
                count = BitConverter.ToUInt16(new[] { lo, hi }, 0);
            }
            else
            {
                count = byteValue; // we already have the data size
            }
 
            //remove high order zeros in data
            while (rd.ReadByte() == 0x00)
            {
                count -= 1;
            }
            rd.BaseStream.Seek(-1, System.IO.SeekOrigin.Current);
 
            return count;
        }
 
        /// <summary>
        ///
        /// </summary>
        /// <param name="pemString"></param>
        /// <param name="type"></param>
        /// <returns></returns>
        public static byte[] GetBytesFromPEM(string pemString, PemStringType type)
        {
            string header; string footer;
 
            switch (type)
            {
                case PemStringType.Certificate:
                    header = "-----BEGIN CERTIFICATE-----";
                    footer = "-----END CERTIFICATE-----";
                    break;
                case PemStringType.RsaPrivateKey:
                    header = "-----BEGIN RSA PRIVATE KEY-----";
                    footer = "-----END RSA PRIVATE KEY-----";
                    break;
                default:
                    return null;
            }
 
            int start = pemString.IndexOf(header) + header.Length;
            int end = pemString.IndexOf(footer, start) - start;
            return Convert.FromBase64String(pemString.Substring(start, end));
        }
 
        /// <summary>
        ///
        /// </summary>
        /// <param name="inputBytes"></param>
        /// <param name="alignSize"></param>
        /// <returns></returns>
        public static byte[] AlignBytes(byte[] inputBytes, int alignSize)
        {
            int inputBytesSize = inputBytes.Length;
 
            if ((alignSize != -1) && (inputBytesSize < alignSize))
            {
                byte[] buf = new byte[alignSize];
                for (int i = 0; i < inputBytesSize; ++i)
                {
                    buf[i + (alignSize - inputBytesSize)] = inputBytes[i];
                }
                return buf;
            }
            else
            {
                return inputBytes; // Already aligned, or doesn't need alignment
            }
        }
    }
}