internal bool TryDrainRemainingDataForGetBytes(Span <byte> bytes, out int bytesWritten)
{
int originalBytesLength = bytes.Length;
Rune thisRune;
while ((thisRune = GetNextRune()).Value != 0)
{
switch (encoding.EncodeRune(thisRune, bytes, out int bytesWrittenJustNow))
{
case OperationStatus.Done:
bytes = bytes.Slice(bytesWrittenJustNow);
continue;
case OperationStatus.DestinationTooSmall:
// Since we're not consuming the Rune we just read, back up as many chars as necessary
// to undo the read we just performed, then report to our caller that we ran out of space.
for (int i = 0; i < thisRune.Utf16SequenceLength; i++)
{
MovePrevious();
}
bytesWritten = originalBytesLength - bytes.Length;
return(false); // ran out of destination buffer
case OperationStatus.InvalidData:
// We can't fallback the fallback. We can't make forward progress, so report to our caller
// that something went terribly wrong. The error message contains the fallback char that
// couldn't be converted. (Ideally we'd provide the first char that originally triggered
// the fallback, but it's complicated to keep this state around, and a fallback producing
// invalid data should be a very rare occurrence.)
ThrowLastCharRecursive(thisRune.Value);
break; // will never be hit; call above throws
default:
Debug.Fail("Unexpected return value.");
break;
}
}
bytesWritten = originalBytesLength - bytes.Length;
return(true); // finished successfully
}
