Function ASNDerWriteLength

spnegotokenhandler/derparse.c:493–568

////////////////////////////////////////////////////////////////////////////

int ASNDerWriteLength(unsigned char* pbData, long nLength)
{
	int   nNumBytesRequired = ASNDerCalcNumLengthBytes(nLength);
	int   nNumLengthBytes = nNumBytesRequired - 1;


	if (nNumBytesRequired > 1)
	{

		// Write out the number of bytes following which will be used
		*pbData = (unsigned char)(LEN_XTND | nNumLengthBytes);

		// Point to where we'll actually write the length
		pbData++;

#ifdef __LITTLE_ENDIAN__

		// There may be a cleaner way to do this, but for now, this seems to be
		// an easy way to do the transformation
		switch (nNumLengthBytes)
		{
		case 1:
		{
			// Cast the length to a single byte, since we know that it
			// is 0x7F or less (or we wouldn't only need a single byte).

			*pbData = (unsigned char)nLength;
			break;
		}

		case 2:
		{
			*pbData = *(((unsigned char*)& nLength) + 1);
			*(pbData + 1) = *(((unsigned char*)& nLength));
			break;
		}

		case 3:
		{
			*pbData = *(((unsigned char*)& nLength) + 3);
			*(pbData + 1) = *(((unsigned char*)& nLength) + 2);
			*(pbData + 2) = *(((unsigned char*)& nLength));
			break;
		}

		case 4:
		{
			*pbData = *(((unsigned char*)& nLength) + 3);
			*(pbData + 1) = *(((unsigned char*)& nLength) + 2);
			*(pbData + 2) = *(((unsigned char*)& nLength) + 1);
			*(pbData + 3) = *(((unsigned char*)& nLength));
			break;
		}

		}  // SWITCH ( nNumLengthBytes )

#else
		// We are Big-Endian, so the length can be copied in from the source