to rethink the specification. Why are you trying to compress data
like this? What other ways are there to compress the data?
Trying to do a lot of bit-twiddling will slow down your application.
Sorry there is a typo in the first post, value3 is 4 bits not 12
It's not up to me how the data is packaged unfortunately, I am dealing
with a platform that has very limited resources so every bit counts.
Probably the most efficient is just to do the bit shifting and
masking as proposed by other.
If you are willing to spend a bit more memory and CPU for the
sake of cleaner code, then I have a little record package
to write and read native structures.
See demo below.
Arne
====================
import dk.vajhoej.record.FieldType;
import dk.vajhoej.record.Struct;
import dk.vajhoej.record.StructField;
import dk.vajhoej.record.StructWriter;
@Struct
public class ThreeBitFields {
@StructField(n=0,type=FieldType.BIT,length=6)
private int value1;
@StructField(n=1,type=FieldType.BIT,length=6)
private int value2;
@StructField(n=2,type=FieldType.BIT,length=4)
private int value3;
public int getValue1() {
return value1;
}
public void setValue1(int value1) {
this.value1 = value1;
}
public int getValue2() {
return value2;
}
public void setValue2(int value2) {
this.value2 = value2;
}
public int getValue3() {
return value3;
}
public void setValue3(int value3) {
this.value3 = value3;
}
public static void main(String[] args) throws Exception {
ThreeBitFields o = new ThreeBitFields();
o.setValue1(1);
o.setValue2(3);
o.setValue3(5);
StructWriter sw = new StructWriter();
sw.write(o);
byte[] b = sw.getBytes();
for(int i = 0; i < b.length; i++) {
System.out.printf("%02X", b[i]);
}
System.out.println();
}
}
All, thanks for your advice.