namespace System.Text { internal class EncodingCharBuffer { private unsafe char* _chars; private unsafe readonly char* _charStart; private unsafe readonly char* _charEnd; private int _charCountResult; private readonly EncodingNLS _enc; private readonly System.Text.DecoderNLS _decoder; private unsafe readonly byte* _byteStart; private unsafe readonly byte* _byteEnd; private unsafe byte* _bytes; private readonly DecoderFallbackBuffer _fallbackBuffer; private DecoderFallbackBufferHelper _fallbackBufferHelper; internal unsafe bool MoreData => _bytes < _byteEnd; internal unsafe int BytesUsed => (int)(_bytes - _byteStart); internal int Count => _charCountResult; internal unsafe EncodingCharBuffer(EncodingNLS enc, System.Text.DecoderNLS decoder, char* charStart, int charCount, byte* byteStart, int byteCount) { _enc = enc; _decoder = decoder; _chars = charStart; _charStart = charStart; _charEnd = charStart + charCount; _byteStart = byteStart; _bytes = byteStart; _byteEnd = byteStart + byteCount; if (_decoder == null) _fallbackBuffer = enc.DecoderFallback.CreateFallbackBuffer(); else _fallbackBuffer = _decoder.FallbackBuffer; _fallbackBufferHelper = new DecoderFallbackBufferHelper(_fallbackBuffer); _fallbackBufferHelper.InternalInitialize(_bytes, _charEnd); } internal unsafe bool AddChar(char ch, int numBytes) { if (_chars != null) { if (_chars >= _charEnd) { _bytes -= numBytes; _enc.ThrowCharsOverflow(_decoder, _bytes <= _byteStart); return false; } char* chars = _chars; _chars = chars + 1; *chars = ch; } _charCountResult++; return true; } internal bool AddChar(char ch) { return AddChar(ch, 1); } internal unsafe bool AddChar(char ch1, char ch2, int numBytes) { if (_chars >= _charEnd - 1) { _bytes -= numBytes; _enc.ThrowCharsOverflow(_decoder, _bytes <= _byteStart); return false; } if (AddChar(ch1, numBytes)) return AddChar(ch2, numBytes); return false; } internal unsafe void AdjustBytes(int count) { _bytes += count; } internal unsafe bool EvenMoreData(int count) { return _bytes <= _byteEnd - count; } internal unsafe byte GetNextByte() { if (_bytes >= _byteEnd) return 0; return *(_bytes++); } internal bool Fallback(byte fallbackByte) { byte[] byteBuffer = new byte[1] { fallbackByte }; return Fallback(byteBuffer); } internal bool Fallback(byte byte1, byte byte2) { byte[] byteBuffer = new byte[2] { byte1, byte2 }; return Fallback(byteBuffer); } internal bool Fallback(byte byte1, byte byte2, byte byte3, byte byte4) { byte[] byteBuffer = new byte[4] { byte1, byte2, byte3, byte4 }; return Fallback(byteBuffer); } internal unsafe bool Fallback(byte[] byteBuffer) { if (_chars != null) { char* chars = _chars; if (!_fallbackBufferHelper.InternalFallback(byteBuffer, _bytes, ref _chars)) { _bytes -= byteBuffer.Length; _fallbackBufferHelper.InternalReset(); _enc.ThrowCharsOverflow(_decoder, _chars == _charStart); return false; } _charCountResult += (int)(_chars - chars); } else _charCountResult += _fallbackBufferHelper.InternalFallback(byteBuffer, _bytes); return true; } } }