private string ReadString()
{
EnsureBuffers();
StringBuilder builder = null;
int totalBytesRead = 0;
// used in case of left over multibyte characters in the buffer
int offset = 0;
while (true)
{
int count = offset;
byte b;
while (count < MaxCharBytesSize && (b = _reader.ReadByte()) > 0)
{
_byteBuffer[count++] = b;
}
int byteCount = count - offset;
totalBytesRead += byteCount;
if (count < MaxCharBytesSize && builder == null)
{
// pref optimization to avoid reading into a string builder
// if string is smaller than the buffer then return it directly
int length = Encoding.UTF8.GetChars(_byteBuffer, 0, byteCount, _charBuffer, 0);
MovePosition(totalBytesRead + 1);
return new string(_charBuffer, 0, length);
}
else
{
// calculate the index of the end of the last full character in the buffer
int lastFullCharStop = GetLastFullCharStop(count - 1);
int charCount = Encoding.UTF8.GetChars(_byteBuffer, 0, lastFullCharStop + 1, _charBuffer, 0);
if (builder == null)
{
builder = new StringBuilder(MaxCharBytesSize * 2);
}
builder.Append(_charBuffer, 0, charCount);
if (lastFullCharStop < byteCount - 1)
{
offset = byteCount - lastFullCharStop - 1;
// copy left over multi byte characters to beginning of buffer for next iteration
Array.Copy(_byteBuffer, lastFullCharStop + 1, _byteBuffer, 0, offset);
}
else
{
// reached end of string
if (count < MaxCharBytesSize)
{
MovePosition(totalBytesRead + 1);
return builder.ToString();
}
offset = 0;
}
}
}
}