◆ ReadBuffer() [2/2]

int System.IO.StreamReader.ReadBuffer	(	Span< char >	userBuffer,
		out bool	readToUserBuffer )
inlineprivate
Definition at line 580 of file StreamReader.cs.
    {
        _charLen = 0;
        _charPos = 0;
        if (!_checkPreamble)
        {
            _byteLen = 0;
        }
        int num = 0;
        readToUserBuffer = userBuffer.Length >= _maxCharsPerBuffer;
        do
        {
            if (_checkPreamble)
            {
                int num2 = _stream.Read(_byteBuffer, _bytePos, _byteBuffer.Length - _bytePos);
                if (num2 == 0)
                {
                    if (_byteLen > 0)
                    {
                        if (readToUserBuffer)
                        {
                            num = _decoder.GetChars(new ReadOnlySpan<byte>(_byteBuffer, 0, _byteLen), userBuffer.Slice(num), flush: false);
                            _charLen = 0;
                        }
                        else
                        {
                            num = _decoder.GetChars(_byteBuffer, 0, _byteLen, _charBuffer, num);
                            _charLen += num;
                        }
                    }
                    return num;
                }
                _byteLen += num2;
            }
            else
            {
                _byteLen = _stream.Read(_byteBuffer, 0, _byteBuffer.Length);
                if (_byteLen == 0)
                {
                    break;
                }
            }
            _isBlocked = _byteLen < _byteBuffer.Length;
            if (!IsPreamble())
            {
                if (_detectEncoding && _byteLen >= 2)
                {
                    DetectEncoding();
                    readToUserBuffer = userBuffer.Length >= _maxCharsPerBuffer;
                }
                _charPos = 0;
                if (readToUserBuffer)
                {
                    num += _decoder.GetChars(new ReadOnlySpan<byte>(_byteBuffer, 0, _byteLen), userBuffer.Slice(num), flush: false);
                    _charLen = 0;
                }
                else
                {
                    num = _decoder.GetChars(_byteBuffer, 0, _byteLen, _charBuffer, num);
                    _charLen += num;
                }
            }
        }
        while (num == 0);
        _isBlocked &= num < userBuffer.Length;
        return num;
    }