datablk.java

jpeg2000编解码

/*
 * CVS Identifier:
 *
 * $Id: DataBlk.java,v 1.2 2002/08/08 08:48:20 grosbois Exp $
 *
 * Interface:           DataBlk
 *
 * Description:         A generic interface to hold 2D blocks of data.
 *
 *
 *
 * COPYRIGHT:
 * 
 * This software module was originally developed by Rapha雔 Grosbois and
 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
 * Askel鰂 (Ericsson Radio Systems AB); and Bertrand Berthelot, David
 * Bouchard, F閘ix Henry, Gerard Mozelle and Patrice Onno (Canon Research
 * Centre France S.A) in the course of development of the JPEG2000
 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
 * software module is an implementation of a part of the JPEG 2000
 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
 * Partners) agree not to assert against ISO/IEC and users of the JPEG
 * 2000 Standard (Users) any of their rights under the copyright, not
 * including other intellectual property rights, for this software module
 * with respect to the usage by ISO/IEC and Users of this software module
 * or modifications thereof for use in hardware or software products
 * claiming conformance to the JPEG 2000 Standard. Those intending to use
 * this software module in hardware or software products are advised that
 * their use may infringe existing patents. The original developers of
 * this software module, JJ2000 Partners and ISO/IEC assume no liability
 * for use of this software module or modifications thereof. No license
 * or right to this software module is granted for non JPEG 2000 Standard
 * conforming products. JJ2000 Partners have full right to use this
 * software module for his/her own purpose, assign or donate this
 * software module to any third party and to inhibit third parties from
 * using this software module for non JPEG 2000 Standard conforming
 * products. This copyright notice must be included in all copies or
 * derivative works of this software module.
 * 
 * Copyright (c) 1999/2000 JJ2000 Partners.
 * */
package jj2000.j2k.image;

import security.*;

/**
 * This is a generic abstract class to store data from a block of an
 * image. This class does not have the notion of components. Therefore, it
 * should be used for data from a single component. Subclasses should
 * implement the different types of storage (<tt>int</tt>, <tt>float</tt>,
 * etc.).
 *
 * <p>The data is always stored in one array, of the type matching the data
 * type (i.e. for 'int' it's an 'int[]'). The data should be stored in the
 * array in standard scan-line order. That is the samples go from the top-left
 * corner of the code-block to the lower-right corner by line and then
 * column.</p>
 *
 * <p>The member variable 'offset' gives the index in the array of the first
 * data element (i.e. the top-left coefficient (ulx,uly)). The member variable
 * 'scanw' gives the width of the scan that is used to store the data, that
 * can be different from the width of the block. Element '(x,y)' of the
 * code-block (i.e. '(ulx,uly)' is the top-left coefficient), will appear at
 * position 'offset+(y-uly)*scanw+(x-ulx)' in the array of data.</p>
 *
 * <p>A block of data can have the <i>progressive</i> attribute set. Data is
 * progressive when it is obtained by successive refinement and the values in
 * this block are approximations of the "final" values. When the final values
 * are returned the progressive attribute must be turned off.</p>
 *
 * <p>The classes <tt>DataBlkInt</tt> and <tt>DataBlkFloat</tt> provide
 * implementations for <tt>int</tt> and <tt>float</tt> types respectively.</p>
 *
 * @see DataBlkInt
 *
 * @see DataBlkFloat
 * */
public abstract class DataBlk {

    /** The identifier for the <tt>byte</tt> data type, as signed 8 bits. */
    public final static int TYPE_BYTE = 0;

    /** The identifier for the <tt>short</tt> data type, as signed 16 bits. */
    public final static int TYPE_SHORT = 1;

    /** The identifier for the <tt>int</tt> data type, as signed 32 bits. */
    public final static int TYPE_INT = 3;

    /** The identifier for the <tt>float</tt> data type */
    public final static int TYPE_FLOAT = 4;

    /** The horizontal coordinate (in pixels) of the upper-left corner of the
     *  block of data. This is relative to the component of the image from
     *  where this block was filled or is to be filled.  */
    public int ulx;

    /** The vertical coordinate of the upper-left corner of the block of
     *  data. This is relative to the component of the image from where this
     *  block was filled or is to be filled.  */
    public int uly;

    /** The width of the block, in pixels. */
    public int w;

    /** The height of the block, in pixels. */
    public int h;

    /** The offset in the array of the top-left coefficient */
    public int offset;

    /** The width of the scanlines used to store the data in the array */
    public int scanw;

    /** The progressive attribute (<tt>false</tt> by default) */
    public boolean progressive;

    /** Whether or not this code-block is or has to be scrambled */
    public boolean scrambled = false;

    /** Scrambling type (only valid if <tt>scrambled</tt> is true) */
    public int scramblingType = ScramblingTypes.NO_SCRAMBLING;

    /** Seed value to use for scrambling */
    public long seed = 0;

    /** First scrambled codewords */
    public int scrambOff = -1;

    /**
     * Returns the size in bits, given the data type. The data type must be
     * one defined in this class. An <tt>IllegalArgumentException</tt> is
     * thrown if <tt>type</tt> is not defined in this class. 
     *
     * @param type The data type.
     *
     * @return The size in bits of the data type.
     * */
    public static int getSize(int type) {
        switch (type) {
        case TYPE_BYTE:
            return 8;
        case TYPE_SHORT:
            return 16;
        case TYPE_INT:
        case TYPE_FLOAT:
            return 32;
        default:
            throw new IllegalArgumentException();
        }
    }
    
    /**
     * Returns the data type of the <tt>DataBlk</tt> object, as
     * defined in this class. Known data type are <tt>TYPE_BYTE</tt>,
     * <tt>TYPE_SHORT</tt>, <tt>TYPE_INT</tt> or <tt>TYPE_FLOAT</tt>.
     *
     * @return The data type of the object, as defined in thsi class.
     * @see #TYPE_BYTE
     * @see #TYPE_SHORT
     * @see #TYPE_INT
     * @see #TYPE_FLOAT
     * */
    public abstract int getDataType();

    /**
     * Returns the array containing the data, or null if there is no data. The
     * returned array is of the type returned by <tt>getDataType()</tt> (e.g.,
     * for <tt>TYPE_INT</tt>, it is a <tt>int[]</tt>).
     *
     * <p>Each implementing class should provide a type specific equivalent
     * method (e.g., <tt>getDataInt()</tt> in <tt>DataBlkInt</tt>) which
     * returns an array of the correct type explicetely and not through an
     * <tt>Object</tt>.</p>
     *
     * @return The array containing the data, or <tt>null</tt> if there is no
     * data.
     *
     * @see #getDataType
     * */
    public abstract Object getData();

    /**
     * Sets the data array to the specified one. The type of the specified
     * data array must match the one returned by <tt>getDataType()</tt> (e.g.,
     * for <tt>TYPE_INT</tt>, it should be a <tt>int[]</tt>). If the wrong
     * type of array is given a <tt>ClassCastException</tt> will be thrown.
     *
     * <p>The size of the array is not necessarily checked for consistency
     * with <tt>w</tt> and <tt>h</tt> or any other fields.</p>
     *
     * <p>Each implementing class should provide a type specific equivalent
     * method (e.g., <tt>setDataInt()</tt> in <tt>DataBlkInt</tt>) which takes
     * an array of the correct type explicetely and not through an
     * <tt>Object</tt>.</p>
     *
     * @param arr The new data array to use
     *
     * @see #getDataType
     * */
    public abstract void setData(Object arr);

    /**
     * Returns a string of informations about the DataBlk
     *
     * @return Block dimensions and progressiveness in a string
     * */
    public String toString(){
	String typeString = "";
	switch(getDataType()){
	case  TYPE_BYTE:
	    typeString = "Unsigned Byte";
	    break;
	case  TYPE_SHORT:
	    typeString = "Short";
	    break;
	case  TYPE_INT:
	    typeString = "Integer";
	    break;
	case  TYPE_FLOAT:
	    typeString = "Float";
	    break;
	}

	return
	    "DataBlk: "+
	    "upper-left("+ulx+","+uly+"), width="+w+
	    ", height="+h+", progressive="+progressive+
            ", offset="+offset+", scanw="+scanw+
	    ", type="+typeString;
    }
}