Bitwise Operation Issues - Java-Gaming.org

Dane

Senior Newbie

Bitwise Operation Issues

« Posted 2013-02-17 11:27:01 »

I can't figure out why this isn't writing/reading properly.

Basically what I'm trying to do is write numbers to an array of bytes, and then read them. It's pretty self-explanatory if you take a look.

Any help would be greatly appreciated.

Test.java:

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import org.valhalla.io.Payload;

public class Test
{

   public Test()
   {
      try {
         Payload p = new Payload(32);
         p.putLong(0x7fffffffffffffffL);
         p.putInt(0xFFFFFF);
         p.putShort(0xFFFF);
         p.put(0xFF);
         p.putFloat(1.234f);
         
         p.reset(); // Resets the position back to zero.
         
         System.out.println("Value: " + p.getLong() + ", " + p.getInt() + ", " + p.getShort() + ", " + p.get() + ", " + p.getFloat());
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

   public static void main(String[] args) {
      new Test();
   }

}

Output:

1	Value: -1, 16777215, 65535, 255, 1.234

Payload.java:

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package org.valhalla.io;

import java.io.IOException;
import java.io.OutputStream;

public class Payload
{

   private byte[] data;
   private int position = 0;
   private OutputStream out;

   public Payload(int size)
   {
      this.data = new byte[size];
   }

   public Payload(OutputStream out, int size)
   {
      this.out = out;
      this.data = new byte[size];
   }

   public Payload(byte[] data)
   {
      this.data = data;
   }

   public int get() {
      return (data[position++] & 0xFF);
   }

   public Payload put(int i) {
      this.data[position++] = (byte) (i & 0xFF);
      return this;
   }

   public boolean getBoolean() {
      return get() == 1;
   }

   public Payload putBoolean(boolean flag) {
      this.put(flag ? 1 : 0);
      return this;
   }

   public int getShort() {
      return get() << 8 | get();
   }

   public Payload putShort(int i) {
      put(i >>> 8);
      put(i);
      return this;
   }

   public int getInt() {
      return getShort() << 16 | getShort();
   }

   public Payload putInt(int i) {
      putShort(i >>> 16);
      putShort(i);
      return this;
   }

   public long getLong() {
      return getInt() << 32L | getInt();
   }

   public Payload putLong(long l) {
      putInt((int) (l >>> 32L));
      putInt((int) l);
      return this;
   }

   public double getDouble() {
      return Double.longBitsToDouble(getLong());
   }

   public Payload putDouble(double d) {
      this.putLong(Double.doubleToLongBits(d));
      return this;
   }

   public float getFloat() {
      return Float.intBitsToFloat(getInt());
   }

   public Payload putFloat(float f) {
      this.putInt(Float.floatToIntBits(f));
      return this;
   }

   public Payload reset() {
      this.position = 0;
      return this;
   }

   public Payload clean() {
      for (int i = 0; i < this.data.length; i++) {
         this.data[i] = 0;
      }
      return this;
   }

   public Payload flush() throws IOException {
      if (this.getOutputStream() == null) {
         System.out.println("Warning: Attempted to flush payload with no output stream!");
         return this;
      }
      out.write(this.data);
      return this.clean().reset();
   }

   public Payload setData(byte[] data) {
      this.data = data;
      return this;
   }

   public final byte[] getData() {
      return this.data;
   }

   public Payload setOutputStream(OutputStream out) {
      this.out = out;
      return this;
   }

   public OutputStream getOutputStream() {
      return this.out;
   }

}

Doing it wrong since 0x7CC.

cylab

JGO Knight

Medals: 30

Re: Bitwise Operation Issues

« Reply #1 - Posted 2013-02-17 12:21:55 »

You clean your payload on every get, since the Pair constructor calls clean() on it...

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      public Pair(Payload payload, T value)
      {
         this.payload = payload;
         this.value = value;
         this.payload.clean().reset();
      }

Unoffensive tip: learn how stepping and variable inspection work in your IDEs debugger Wink

Btw. this code produces a lot of garbage (memory management wise), since you effectively creating multiple temporary Pair objects on every get call. Better refactor the gets to some equivalents of your put mechanism.

Mathias - I Know What [you] Did Last Summer!

Dane

Senior Newbie

Re: Bitwise Operation Issues

« Reply #2 - Posted 2013-02-17 12:39:01 »

Quote from: cylab on 2013-02-17 12:21:55

You clean your payload on every get, since the Pair constructor calls clean() on it...

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      public Pair(Payload payload, T value)
      {
         this.payload = payload;
         this.value = value;
         this.payload.clean().reset();
      }

Unoffensive tip: learn how stepping and variable inspection work in your IDEs debugger Wink

Thanks for this, I don't know what I was thinking when I put that in the constructor. Completely my fault for working on this at 3AM in the morning.

Also I hope I refactored properly, I've edited the original post with the updated source.

Edit: Also it appears getDouble or putDouble may not be working properly.

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         Payload p = new Payload(32);
          p.putDouble(123.10d);
         p.putFloat(123.10f);
         p.putLong(0x73FD73FDL);

         p.reset();

         System.out.println("Double: " + p.getDouble() + ", Float: " + p.getFloat() + ", Long: " + Long.toHexString(p.getLong()));

Output:

1	Double: 8.49591604E-315, Float: 123.1, Long: 73fd73fd

Doing it wrong since 0x7CC.

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