Question

In java I have put one byte like this. How do I reserve next 3 bytes? I heard that it’s better to pack data in multiples of 4 bytes

final byte PACKET_TYPE = 3;
bBuffer.put(PACKET_TYPE);

Also, if I want to fix a string data field as 48 bytes then how do I handle if string data is less than 48 bytes? I don’t want to add the size of string…

Thanks in advance…

Answer 1

In a word, padding:

final byte PACKET_TYPE = 3;
final byte PAD_BYTE = 0;
bBuffer.put(PACKET_TYPE);
bBuffer.put(PAD_BYTE);
bBuffer.put(PAD_BYTE);
bBuffer.put(PAD_BYTE);

For a fixed-width string field, you could pad with null bytes (a byte of 0), assuming, of course, that the string itself will never contain such bytes.