K2Informatics.Erlnet.OtpInputStream.byte_array_to_long C# (CSharp) Method

        public static long byte_array_to_long(byte[] b, bool unsigned)
        {
            long v = 0;
            switch (b.Length)
            {
                case 0:
                    v = 0;
                    break;
                case 2:
                    v = ((b[0] & 0xFF) << 8) + (b[1] & 0xFF);
                    v = (short)v; // Sign extend
                    if (v < 0 && unsigned)
                    {
                        throw new OtpErlangDecodeException("Value not unsigned: " + v);
                    }
                    break;
                case 4:
                    v = ((b[0] & 0xFF) << 24) + ((b[1] & 0xFF) << 16)
                        + ((b[2] & 0xFF) << 8) + (b[3] & 0xFF);
                    v = (int)v; // Sign extend
                    if (v < 0 && unsigned)
                    {
                        throw new OtpErlangDecodeException("Value not unsigned: " + v);
                    }
                    break;
                default:
                    int i = 0;
                    byte c = b[i];
                    // Skip non-essential leading bytes
                    if (unsigned)
                    {
                        if (c < 0)
                        {
                            throw new OtpErlangDecodeException("Value not unsigned: " + b);
                        }
                        while (b[i] == 0)
                        {
                            i++; // Skip leading zero sign bytes
                        }
                    }
                    else
                    {
                        if (c == 0 || c == 0xFF) // Leading sign byte
                        {
                            i = 1;
                            // Skip all leading sign bytes
                            while (i < b.Length && b[i] == c)
                            {
                                i++;
                            }
                            if (i < b.Length)
                            {
                                // Check first non-sign byte to see if its sign
                                // matches the whole number's sign. If not one more
                                // byte is needed to represent the value.
                                if (((c ^ b[i]) & 0x80) != 0)
                                {
                                    i--;
                                }
                            }
                        }
                    }
                    if (b.Length - i > 8)
                    {
                        // More than 64 bits of value
                        throw new OtpErlangDecodeException("Value does not fit in long: " + b);
                    }
                    // Convert the necessary bytes
                    for (v = c < 0 ? -1 : 0; i < b.Length; i++)
                    {
                        v = (long)((((ulong)v) << 8) | ((ulong)(b[i] & 0xFF)));
                    }
                    break;
            }
            return v;
        }