System.Collections.BitArray.BitArray C# (CSharp) Method

        public BitArray(byte[] bytes)
        {
            if (bytes == null)
            {
                throw new ArgumentNullException(nameof(bytes));
            }
            Contract.EndContractBlock();
            // this value is chosen to prevent overflow when computing m_length.
            // m_length is of type int32 and is exposed as a property, so 
            // type of m_length can't be changed to accommodate.
            if (bytes.Length > int.MaxValue / BitsPerByte)
            {
                throw new ArgumentException(SR.Format(SR.Argument_ArrayTooLarge, BitsPerByte), nameof(bytes));
            }

            m_array = new int[GetArrayLength(bytes.Length, BytesPerInt32)];
            m_length = bytes.Length * BitsPerByte;

            int i = 0;
            int j = 0;
            while (bytes.Length - j >= 4)
            {
                m_array[i++] = (bytes[j] & 0xff) |
                              ((bytes[j + 1] & 0xff) << 8) |
                              ((bytes[j + 2] & 0xff) << 16) |
                              ((bytes[j + 3] & 0xff) << 24);
                j += 4;
            }

            Debug.Assert(bytes.Length - j >= 0, "BitArray byteLength problem");
            Debug.Assert(bytes.Length - j < 4, "BitArray byteLength problem #2");

            switch (bytes.Length - j)
            {
                case 3:
                    m_array[i] = ((bytes[j + 2] & 0xff) << 16);
                    goto case 2;
                // fall through
                case 2:
                    m_array[i] |= ((bytes[j + 1] & 0xff) << 8);
                    goto case 1;
                // fall through
                case 1:
                    m_array[i] |= (bytes[j] & 0xff);
                    break;
            }

            _version = 0;
        }