DataReader.java

/**
 *
 */
package de.deaod.wc3doo;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteOrder;

/**
 * Class to read multi-byte integers and floats from an input Stream
 *
 * @author Deaod <[email protected]>
 * @version 1.0
 * @see InputStream
 */
public class DataReader {
    private ByteOrder   byteOrder = ByteOrder.nativeOrder();
    private InputStream input;

    /**
     * Constructs a reader with the specified input stream as input.
     *
     * @param input the input stream to read from.
     */
    public DataReader(InputStream input) {
        this.input = input;
    }

    /**
     * Constructs a reader with the specified input stream as input and the specified byte order as default byte order.
     *
     * @param input the input stream to read from.
     * @param byteOrder the byte order to use as default.
     */
    public DataReader(InputStream input, ByteOrder byteOrder) {
        this.input = input;
        this.byteOrder = byteOrder;
    }

    //

    /**
     * Returns the default byte order with which to read from the array. After constructing an instance of DataReader,
     * the default byte order is the native one.
     *
     * @return The default byte order with which to read from the array.
     * @see #readShort()
     * @see #readInt()
     * @see #readLong()
     * @see #readFloat()
     * @see #readDouble()
     * @see ByteOrder
     */
    public ByteOrder getByteOrder() {
        return this.byteOrder;
    }

    /**
     * Changes the default byte order to the specified one.
     *
     * @param byteOrder the new default byte order
     * @see #readShort()
     * @see #readInt()
     * @see #readLong()
     * @see #readFloat()
     * @see #readDouble()
     * @see ByteOrder
     */
    public void setByteOrder(ByteOrder byteOrder) {
        this.byteOrder = byteOrder;
    }

    //

    /**
     * Reads an 8-bit integer from the input stream. Blocks until the next byte is available.
     *
     * @return The 8-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public byte readByte() throws IOException {
        int b = this.input.read();
        if (b < 0)
            throw new IOException("Unexpected End of Stream");
        return (byte) b;
    }

    //

    /**
     * Reads a 16-bit integer from the input stream with Little Endian byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 16-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public short readShortLE() throws IOException {
        short result = 0;
        result |= (readByte() << 0) & 0x00FF;
        result |= (readByte() << 8) & 0xFF00;
        return result;
    }

    /**
     * Reads a 16-bit integer from the input stream with Big Endian byte order. Blocks until enough bytes have been read
     * from the input stream.
     *
     * @return The 16-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public short readShortBE() throws IOException {
        short result = 0;
        result |= (readByte() << 8) & 0xFF00;
        result |= (readByte() << 0) & 0x00FF;
        return result;
    }

    /**
     * Reads a 16-bit integer from the input stream with the default byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 16-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     * @see #getByteOrder()
     * @see #setByteOrder(ByteOrder)
     */
    public short readShort() throws IOException {
        if (this.byteOrder == ByteOrder.BIG_ENDIAN) {
            return readShortBE();
        } else {
            return readShortLE();
        }
    }

    //

    /**
     * Reads a 32-bit integer from the input stream with Little Endian byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 32-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public int readIntLE() throws IOException {
        int result = 0;
        result |= (readByte() << 0) & 0x000000FF;
        result |= (readByte() << 8) & 0x0000FF00;
        result |= (readByte() << 16) & 0x00FF0000;
        result |= (readByte() << 24) & 0xFF000000;
        return result;
    }

    /**
     * Reads a 32-bit integer from the input stream with Big Endian byte order. Blocks until enough bytes have been read
     * from the input stream.
     *
     * @return The 32-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public int readIntBE() throws IOException {
        int result = 0;
        result |= (readByte() << 24) & 0xFF000000;
        result |= (readByte() << 16) & 0x00FF0000;
        result |= (readByte() << 8) & 0x0000FF00;
        result |= (readByte() << 0) & 0x000000FF;
        return result;
    }

    /**
     * Reads a 32-bit integer from the input stream with the default byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 32-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     * @see #getByteOrder()
     * @see #setByteOrder(ByteOrder)
     */
    public int readInt() throws IOException {
        if (this.byteOrder == ByteOrder.BIG_ENDIAN) {
            return readIntBE();
        } else {
            return readIntLE();
        }
    }

    //

    /**
     * Reads a 64-bit integer from the input stream with Little Endian byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 64-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public long readLongLE() throws IOException {
        long result = 0;
        result |= ((long) readByte() << 0L) & 0x00000000000000FFL;
        result |= ((long) readByte() << 8L) & 0x000000000000FF00L;
        result |= ((long) readByte() << 16L) & 0x0000000000FF0000L;
        result |= ((long) readByte() << 24L) & 0x00000000FF000000L;
        result |= ((long) readByte() << 32L) & 0x000000FF00000000L;
        result |= ((long) readByte() << 40L) & 0x0000FF0000000000L;
        result |= ((long) readByte() << 48L) & 0x00FF000000000000L;
        result |= ((long) readByte() << 56L) & 0xFF00000000000000L;
        return result;
    }

    /**
     * Reads a 64-bit integer from the input stream with Big Endian byte order. Blocks until enough bytes have been read
     * from the input stream.
     *
     * @return The 64-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     */
    public long readLongBE() throws IOException {
        long result = 0;
        result |= ((long) readByte() << 56L) & 0xFF00000000000000L;
        result |= ((long) readByte() << 48L) & 0x00FF000000000000L;
        result |= ((long) readByte() << 40L) & 0x0000FF0000000000L;
        result |= ((long) readByte() << 32L) & 0x000000FF00000000L;
        result |= ((long) readByte() << 24L) & 0x00000000FF000000L;
        result |= ((long) readByte() << 16L) & 0x0000000000FF0000L;
        result |= ((long) readByte() << 8L) & 0x000000000000FF00L;
        result |= ((long) readByte() << 0L) & 0x00000000000000FFL;
        return result;
    }

    /**
     * Reads a 64-bit integer from the input stream with the default byte order. Blocks until enough bytes have been
     * read from the input stream.
     *
     * @return The 64-bit integer value read from the input stream.
     * @throws IOException if the underlying input stream throws an exception or the end of the input stream is reached
     *             unexpectedly.
     * @see #getByteOrder()
     * @see #setByteOrder(ByteOrder)
     */
    public long readLong() throws IOException {
        if (this.byteOrder == ByteOrder.BIG_ENDIAN) {
            return readLongBE();
        } else {
            return readLongLE();
        }
    }

    //

    public float readFloatLE() throws IOException {
        return Float.intBitsToFloat(readIntLE());
    }

    public float readFloatBE() throws IOException {
        return Float.intBitsToFloat(readIntBE());
    }

    public float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }

    //

    public double readDoubleLE() throws IOException {
        return Double.longBitsToDouble(readLongLE());
    }

    public double readDoubleBE() throws IOException {
        return Double.longBitsToDouble(readLongBE());
    }

    public double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }

    //

    public int read(byte[] destination, int offset, int length) throws IOException {
        return this.input.read(destination, offset, length);
    }

    public int read(byte[] destination) throws IOException {
        return read(destination, 0, destination.length);
    }
}