public override void Convert( byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed ) {
bytesUsed = 0;
charsUsed = 0;
// finish a character from the bytes that were cached last time
int i = 0;
int lbc = lastBytesCount;
if ( lbc > 0 ) {
// copy remaining bytes into the cache
for ( ; lbc < 4 && byteCount > 0; lbc++ ) {
lastBytes[lbc] = bytes[byteIndex];
byteIndex++;
byteCount--;
bytesUsed++;
}
// still not enough bytes -> return
if ( lbc < 4 ) {
lastBytesCount = lbc;
completed = true;
return;
}
// decode 1 character from the byte cache
i = GetFullChars( lastBytes, 0 , 4, chars, charIndex );
Debug.Assert( i == 1 );
charIndex += i;
charCount -= i;
charsUsed = i;
lastBytesCount = 0;
// if that's all that was requested -> return
if ( charCount == 0 ) {
completed = ( byteCount == 0 );
return;
}
}
else {
i = 0;
}
// modify the byte count for GetFullChars depending on how many characters were requested
if ( charCount * 4 < byteCount ) {
byteCount = charCount * 4;
completed = false;
}
else {
completed = true;
}
bytesUsed += byteCount;
// decode block of byte quadruplets
charsUsed = GetFullChars( bytes, byteIndex, byteCount, chars, charIndex ) + i;
// cache remaining bytes that does not make up a character
int bytesLeft = ( byteCount & 0x3 );
if ( bytesLeft >= 0 ) {
for( int j = 0; j < bytesLeft; j++ ) {
lastBytes[j] = bytes[byteIndex + byteCount - bytesLeft + j];
}
lastBytesCount = bytesLeft;
}
}
