Convert int to unsigned short java

Question

I have written a .obj parser in java to modelize 3D objects on iPhone. I would like to export the data as a binary file, which must be as small as possible. I have plenty of indices that would fit a unsigned short, but they are represented as int in java.

I would like to use the ByteBuffer class to do the conversion just before writing the data in a file. I suppose I will have to manipulate bytes before pushing them into the ByteBuffer but I have no idea how to do so.

Thank you in advance if you can help me.

There is no such thing as an unsigned anything in java... – Andrew White Jul 06 '11 at 16:11 — Andrew White, Jul 06 '11 at 16:11
Why not just cast to char ? This results in 16 bits – Mike Kwan Jul 06 '11 at 16:11 — Mike Kwan, Jul 06 '11 at 16:11
@Andrew White yes I know that, I wouldn't ask if I didn't. – Friedrik Jul 06 '11 at 16:17 — Friedrik, Jul 06 '11 at 16:17

score 11 · Accepted Answer · answered Jul 06 '11 at 16:10

11

In Java, an unsigned short can be represented as a char. Just cast the int to char and use putChar() on the ByteBuffer.

myBuffer.putChar((char) my16BitInt);

answered Jul 06 '11 at 16:10

Michael Myers

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+1: This does the same as `myBuffer.putShort((short) my16BitInt);` – Peter Lawrey Jul 06 '11 at 16:20

Martijn Courteaux · Answer 2 · 2017-01-12T21:07:11.453

4

short toUint16(int i)
{
    return (short) i;
}

int toUint32(short s)
{
    return s & 0xFFFF;
}

edited Jan 12 '17 at 21:07

answered Jul 06 '11 at 16:16

Martijn Courteaux

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`return s & 0xFFFF;` – Winter Jan 12 '17 at 18:26

score 2 · Answer 3 · answered Jul 06 '11 at 16:11

2

You can extract single bytes from your integers with

int i;
byte b1 = i & 0xFF;
byte b2 = (i >> 8) & 0xFF;

answered Jul 06 '11 at 16:11

Darcara

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score 0 · Answer 4 · answered Jul 06 '11 at 16:13

0

Use http://download.oracle.com/javase/6/docs/api/java/io/DataOutputStream.html

dos.writeShort(value & 0xFFFF);

answered Jul 06 '11 at 16:13

Leonard Brünings

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Convert int to unsigned short java

4 Answers4

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