comparing byte arrays

Question

I have two byte-arrays (in Java) representing two (possibly negative) numbers.

How do I compare them (ie., finding out which one is smaller/greater)?

Currently, I just compare them by resurrecting them into two java's int and then doing the comparison. But that'd give the wrong result in cases where one of the byte-array represents a negative number and the other positive.It's impossible to tell whether the left-most bit is the sign or just part of the number, right?

Thanks

stackoverflow.com/questions/1026761/… - look it up over here. — user
– user, Commented Oct 19, 2012 at 21:30
Are your bytes ordered from most significant to least or the other way? If from most to least: Isn't the left-most bit the sign in the first byte and just part of the number in all following bytes? Do you have a constant number of bytes, or do they vary? — jlordo
– jlordo, Commented Oct 19, 2012 at 22:08
If they're both guaranteed to be 4 bytes, the leftmost bit is always the sign bit. — Louis Wasserman
– Louis Wasserman, Commented Oct 19, 2012 at 22:15

Mirko Adari · Accepted Answer · 2012-10-19 21:59:22Z

3

Why reinvent the wheel? Use ByteBuffer:

int a = ByteBuffer.wrap(byteArrayA).getInt();
int b = ByteBuffer.wrap(byteArrayB).getInt();
System.out.println(a == b);

answered Oct 19, 2012 at 21:59

Mirko Adari

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1 Comment

Mirko Adari Over a year ago

You can specify order with ByteBuffer. order(ByteOrder.BIG_ENDIAN)

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