System.Net.WebUtility.UrlDecodeInternal C# (CSharp) Method

        private static byte[] UrlDecodeInternal(byte[] bytes, int offset, int count)
        {
            if (!ValidateUrlEncodingParameters(bytes, offset, count))
            {
                return null;
            }

            int decodedBytesCount = 0;
            byte[] decodedBytes = new byte[count];

            for (int i = 0; i < count; i++)
            {
                int pos = offset + i;
                byte b = bytes[pos];

                if (b == '+')
                {
                    b = (byte)' ';
                }
                else if (b == '%' && i < count - 2)
                {
                    int h1 = HexToInt((char)bytes[pos + 1]);
                    int h2 = HexToInt((char)bytes[pos + 2]);

                    if (h1 >= 0 && h2 >= 0)
                    {     // valid 2 hex chars
                        b = (byte)((h1 << 4) | h2);
                        i += 2;
                    }
                }

                decodedBytes[decodedBytesCount++] = b;
            }

            if (decodedBytesCount < decodedBytes.Length)
            {
                Array.Resize(ref decodedBytes, decodedBytesCount);
            }

            return decodedBytes;
        }