internal override unsafe int GetBytes(char *chars, int charCount,
byte *bytes, int byteCount, EncoderNLS baseEncoder)
{
Debug.Assert(byteCount >= 0, "[UTF7Encoding.GetBytes]byteCount >=0");
Debug.Assert(chars != null, "[UTF7Encoding.GetBytes]chars!=null");
Debug.Assert(charCount >= 0, "[UTF7Encoding.GetBytes]charCount >=0");
// Get encoder info
UTF7Encoding.Encoder encoder = (UTF7Encoding.Encoder)baseEncoder;
// Default bits & count
int bits = 0;
int bitCount = -1;
// prepare our helpers
Encoding.EncodingByteBuffer buffer = new Encoding.EncodingByteBuffer(
this, encoder, bytes, byteCount, chars, charCount);
if (encoder != null)
{
bits = encoder.bits;
bitCount = encoder.bitCount;
// May have had too many left over
while (bitCount >= 6)
{
bitCount -= 6;
// If we fail we'll never really have enough room
if (!buffer.AddByte(_base64Bytes[(bits >> bitCount) & 0x3F]))
{
ThrowBytesOverflow(encoder, buffer.Count == 0);
}
}
}
while (buffer.MoreData)
{
char currentChar = buffer.GetNextChar();
if (currentChar < 0x80 && _directEncode[currentChar])
{
if (bitCount >= 0)
{
if (bitCount > 0)
{
// Try to add the next byte
if (!buffer.AddByte(_base64Bytes[bits << 6 - bitCount & 0x3F]))
{
break; // Stop here, didn't throw
}
bitCount = 0;
}
// Need to get emit '-' and our char, 2 bytes total
if (!buffer.AddByte((byte)'-'))
{
break; // Stop here, didn't throw
}
bitCount = -1;
}
// Need to emit our char
if (!buffer.AddByte((byte)currentChar))
{
break; // Stop here, didn't throw
}
}
else if (bitCount < 0 && currentChar == '+')
{
if (!buffer.AddByte((byte)'+', (byte)'-'))
{
break; // Stop here, didn't throw
}
}
else
{
if (bitCount < 0)
{
// Need to emit a + and 12 bits (3 bytes)
// Only 12 of the 16 bits will be emitted this time, the other 4 wait 'til next time
if (!buffer.AddByte((byte)'+'))
{
break; // Stop here, didn't throw
}
// We're now in bit mode, but haven't stored data yet
bitCount = 0;
}
// Add our bits
bits = bits << 16 | currentChar;
bitCount += 16;
while (bitCount >= 6)
{
bitCount -= 6;
if (!buffer.AddByte(_base64Bytes[(bits >> bitCount) & 0x3F]))
{
bitCount += 6; // We didn't use these bits
currentChar = buffer.GetNextChar(); // We're processing this char still, but AddByte
// --'d it when we ran out of space
break; // Stop here, not enough room for bytes
}
}
if (bitCount >= 6)
{
break; // Didn't have room to encode enough bits
}
}
}
// Now if we have bits left over we have to encode them.
// MustFlush may have been cleared by encoding.ThrowBytesOverflow earlier if converting
if (bitCount >= 0 && (encoder == null || encoder.MustFlush))
{
// Do we have bits we have to stick in?
if (bitCount > 0)
{
if (buffer.AddByte(_base64Bytes[(bits << (6 - bitCount)) & 0x3F]))
{
// Emitted spare bits, 0 bits left
bitCount = 0;
}
}
// If converting and failed bitCount above, then we'll fail this too
if (buffer.AddByte((byte)'-'))
{
// turned off bit mode';
bits = 0;
bitCount = -1;
}
else
{
// If not successful, convert will maintain state for next time, also
// AddByte will have decremented our char count, however we need it to remain the same
buffer.GetNextChar();
}
}
// Do we have an encoder we're allowed to use?
// bytes == null if counting, so don't use encoder then
if (bytes != null && encoder != null)
{
// We already cleared bits & bitcount for mustflush case
encoder.bits = bits;
encoder.bitCount = bitCount;
encoder._charsUsed = buffer.CharsUsed;
}
return(buffer.Count);
}
