Scala example source code file (ByteArray.java)

This example Scala source code file (ByteArray.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

byte_block_bits, byte_block_bits, byte_block_mask, byte_block_mask, byte_block_size, byte_block_size, bytearray, bytearray, io, ioexception, the

The Scala ByteArray.java source code

/* FJBG -- Fast Java Bytecode Generator
 * Copyright 2002-2011 LAMP/EPFL
 * @author  Michel Schinz
 */

package ch.epfl.lamp.util;

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

/**
 * Array of bytes.
 *
 * @author Michel Schinz
 * @version 1.0
 */

public class ByteArray {
    protected final static int BYTE_BLOCK_BITS = 8;
    protected final static int BYTE_BLOCK_SIZE = 1 << BYTE_BLOCK_BITS;
    protected final static int BYTE_BLOCK_MASK = BYTE_BLOCK_SIZE - 1;

    protected byte[][] data = new byte[][] { new byte[BYTE_BLOCK_SIZE] };
    protected int pos = 0;  // The next free position.

    protected boolean frozen = false;

    public ByteArray() { }

    public ByteArray(InputStream stream, int size) throws IOException {
        pos = size;
        for (int i = 0; size > 0; ++i) {
            int sizeToRead = Math.min(BYTE_BLOCK_SIZE, size);
            stream.read(data[i], 0, sizeToRead);

            size -= sizeToRead;
            if (size > 0) addNewBlock();
        }
    }

    public void freeze() { frozen = true; }

    public int nextBytePosition() {
        return pos;
    }

    public int getSize() {
        return pos;
    }

    protected void addNewBlock() {
        int nextBlockPos = pos >>> BYTE_BLOCK_BITS;
        if (nextBlockPos == data.length) {
            byte[][] newData = new byte[data.length * 2][];
            System.arraycopy(data, 0, newData, 0, data.length);
            data = newData;
        }
        assert data[nextBlockPos] == null : pos + " " + nextBlockPos;
        data[nextBlockPos] = new byte[BYTE_BLOCK_SIZE];
    }

    protected void addByte(int b) {
        assert !frozen;

        if ((pos & BYTE_BLOCK_MASK) == 0 && pos > 0)
            addNewBlock();
        int currPos = pos++;
        data[currPos >>> BYTE_BLOCK_BITS][currPos & BYTE_BLOCK_MASK] = (byte)b;
    }

    public void addU1(int i) {
        assert i <= 0xFF : i;
        addByte(i);
    }

    public void addU2(int i) {
        assert i <= 0xFFFF : i;

        addByte(i >>> 8);
        addByte(i & 0xFF);
    }

    public void addU4(int i) {
        addByte(i >>> 24);
        addByte((i >>> 16) & 0xFF);
        addByte((i >>>  8) & 0xFF);
        addByte(i & 0xFF);
    }

    public void putByte(int targetPos, int b) {
        assert !frozen;
        assert targetPos < pos : targetPos + " >= " + pos;

        data[targetPos >>> BYTE_BLOCK_BITS][targetPos & BYTE_BLOCK_MASK] = (byte)b;
    }

    public void putU2(int targetPos, int i) {
        assert i < 0xFFFF : i;
        putByte(targetPos, i >>> 8);
        putByte(targetPos + 1, i & 0xFF);
    }

    public void putU4(int targetPos, int i) {
        putByte(targetPos, i >>> 24);
        putByte(targetPos + 1, (i >>> 16) & 0xFF);
        putByte(targetPos + 2, (i >>>  8) & 0xFF);
        putByte(targetPos + 3, i & 0xFF);
    }

    public int getU1(int sourcePos) {
        assert sourcePos < pos : sourcePos + " >= " + pos;
        return data[sourcePos >>> BYTE_BLOCK_BITS][sourcePos & BYTE_BLOCK_MASK] & 0xFF;
    }

    public int getU2(int sourcePos) {
        return (getU1(sourcePos) << 8) | getU1(sourcePos + 1);
    }

    public int getU4(int sourcePos) {
        return (getU2(sourcePos) << 16) | getU2(sourcePos + 2);
    }

    public int getS1(int sourcePos) {
        assert sourcePos < pos : sourcePos + " >= " + pos;
        return data[sourcePos >>> BYTE_BLOCK_BITS][sourcePos & BYTE_BLOCK_MASK];
    }

    public int getS2(int sourcePos) {
        return (getS1(sourcePos) << 8) | getU1(sourcePos + 1);
    }

    public int getS4(int sourcePos) {
        return (getS2(sourcePos) << 16) | getU2(sourcePos + 2);
    }

    public void writeTo(OutputStream stream) throws IOException {
        if (!frozen) freeze();

        for (int i = 0; i < data.length && data[i] != null; ++i) {
            int len = Math.min(BYTE_BLOCK_SIZE, pos - (i << BYTE_BLOCK_BITS));
            stream.write(data[i], 0, len);
        }
    }
}