System.Security.Cryptography.FromBase64Transform.ConvertFromBase64 C# (CSharp) Method

        private byte[] ConvertFromBase64(byte[] temp, int effectiveCount)
        {
            // Get the number of 4 bytes blocks to transform
            int numBlocks = (effectiveCount + _inputIndex) / 4;

            byte[] transformBuffer = new byte[_inputIndex + effectiveCount];
            Buffer.BlockCopy(_inputBuffer, 0, transformBuffer, 0, _inputIndex);
            Buffer.BlockCopy(temp, 0, transformBuffer, _inputIndex, effectiveCount);

            _inputIndex = (effectiveCount + _inputIndex) % 4;
            Buffer.BlockCopy(temp, effectiveCount - _inputIndex, _inputBuffer, 0, _inputIndex);

            char[] tempChar = Encoding.ASCII.GetChars(transformBuffer, 0, 4 * numBlocks);
            byte[] tempBytes = Convert.FromBase64CharArray(tempChar, 0, 4 * numBlocks);
            return tempBytes;
        }