/*

 ============================================================================
                   The Apache Software License, Version 1.1
 ============================================================================

 Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.

 Redistribution and use in source and binary forms, with or without modifica-
 tion, are permitted provided that the following conditions are met:

 1. Redistributions of  source code must  retain the above copyright  notice,
    this list of conditions and the following disclaimer.

 2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

 3. The end-user documentation included with the redistribution, if any, must
    include  the following  acknowledgment:  "This product includes  software
    developed  by the  Apache Software Foundation  (http://www.apache.org/)."
    Alternately, this  acknowledgment may  appear in the software itself,  if
    and wherever such third-party acknowledgments normally appear.

 4. The names "Batik" and  "Apache Software Foundation" must  not  be
    used to  endorse or promote  products derived from  this software without
    prior written permission. For written permission, please contact
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 5. Products  derived from this software may not  be called "Apache", nor may
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 FITNESS  FOR A PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN NO  EVENT SHALL  THE
 APACHE SOFTWARE  FOUNDATION  OR ITS CONTRIBUTORS  BE LIABLE FOR  ANY DIRECT,
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 This software  consists of voluntary contributions made  by many individuals
 on  behalf of the Apache Software  Foundation. For more  information on the
 Apache Software Foundation, please see <http://www.apache.org/>.

*/

package org.apache.batik.ext.awt.image.codec.tiff;

import java.io.Serializable;

/**
 * A class representing a field in a TIFF 6.0 Image File Directory.
 *
 * <p> The TIFF file format is described in more detail in the
 * comments for the TIFFDescriptor class.
 *
 * <p> A field in a TIFF Image File Directory (IFD).  A field is defined
 * as a sequence of values of identical data type.  TIFF 6.0 defines
 * 12 data types, which are mapped internally onto the Java datatypes
 * byte, int, long, float, and double.
 *
 * <p><b> This class is not a committed part of the JAI API.  It may
 * be removed or changed in future releases of JAI.</b>
 *
 * @see TIFFDirectory
 */
public class TIFFField extends Object implements Comparable, Serializable {

    /** Flag for 8 bit unsigned integers. */
    public static final int TIFF_BYTE      =  1;

    /** Flag for null-terminated ASCII strings. */
    public static final int TIFF_ASCII     =  2;

    /** Flag for 16 bit unsigned integers. */
    public static final int TIFF_SHORT     =  3;

    /** Flag for 32 bit unsigned integers. */
    public static final int TIFF_LONG      =  4;

    /** Flag for pairs of 32 bit unsigned integers. */
    public static final int TIFF_RATIONAL  =  5;

    /** Flag for 8 bit signed integers. */
    public static final int TIFF_SBYTE     =  6;

    /** Flag for 8 bit uninterpreted bytes. */
    public static final int TIFF_UNDEFINED =  7;

    /** Flag for 16 bit signed integers. */
    public static final int TIFF_SSHORT    =  8;

    /** Flag for 32 bit signed integers. */
    public static final int TIFF_SLONG     =  9;

    /** Flag for pairs of 32 bit signed integers. */
    public static final int TIFF_SRATIONAL = 10;

    /** Flag for 32 bit IEEE floats. */
    public static final int TIFF_FLOAT     = 11;

    /** Flag for 64 bit IEEE doubles. */
    public static final int TIFF_DOUBLE    = 12;

    /** The tag number. */
    int tag;

    /** The tag type. */
    int type;

    /** The number of data items present in the field. */
    int count;

    /** The field data. */
    Object data;
    
    /** The default constructor. */
    TIFFField() {}

    /**
     * Constructs a TIFFField with arbitrary data.  The data
     * parameter must be an array of a Java type appropriate for the
     * type of the TIFF field.  Since there is no available 32-bit
     * unsigned datatype, long is used. The mapping between types is
     * as follows:
     *
     * <table border=1>
     * <tr>
     * <th> TIFF type </th> <th> Java type </th>
     * <tr>
     * <td><tt>TIFF_BYTE</tt></td>      <td><tt>byte</tt></td>
     * <tr>
     * <td><tt>TIFF_ASCII</tt></td>     <td><tt>String</tt></td>
     * <tr>
     * <td><tt>TIFF_SHORT</tt></td>     <td><tt>char</tt></td>
     * <tr>
     * <td><tt>TIFF_LONG</tt></td>      <td><tt>long</tt></td>
     * <tr>
     * <td><tt>TIFF_RATIONAL</tt></td>  <td><tt>long[2]</tt></td>
     * <tr>
     * <td><tt>TIFF_SBYTE</tt></td>     <td><tt>byte</tt></td>
     * <tr>
     * <td><tt>TIFF_UNDEFINED</tt></td> <td><tt>byte</tt></td>
     * <tr>
     * <td><tt>TIFF_SSHORT</tt></td>    <td><tt>short</tt></td>
     * <tr>
     * <td><tt>TIFF_SLONG</tt></td>     <td><tt>int</tt></td>
     * <tr>
     * <td><tt>TIFF_SRATIONAL</tt></td> <td><tt>int[2]</tt></td>
     * <tr>
     * <td><tt>TIFF_FLOAT</tt></td>     <td><tt>float</tt></td>
     * <tr>
     * <td><tt>TIFF_DOUBLE</tt></td>    <td><tt>double</tt></td>
     * </table>
     */
    public TIFFField(int tag, int type, int count, Object data) {
        this.tag = tag;
        this.type = type;
        this.count = count;
        this.data = data;
    }

    /**
     * Returns the tag number, between 0 and 65535.
     */
    public int getTag() {
        return tag;
    }

    /**
     * Returns the type of the data stored in the IFD.
     * For a TIFF6.0 file, the value will equal one of the
     * TIFF_ constants defined in this class.  For future
     * revisions of TIFF, higher values are possible.
     *
     */
    public int getType() {
        return type;
    }

    /**
     * Returns the number of elements in the IFD.
     */
    public int getCount() {
        return count;
    }

    /**
     * Returns the data as an uninterpreted array of bytes.
     * The type of the field must be one of TIFF_BYTE, TIFF_SBYTE,
     * or TIFF_UNDEFINED;
     *
     * <p> For data in TIFF_BYTE format, the application must take
     * care when promoting the data to longer integral types
     * to avoid sign extension.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_BYTE, TIFF_SBYTE, or TIFF_UNDEFINED.
     */
    public byte[] getAsBytes() {
        return (byte[])data;
    }

    /**
     * Returns TIFF_SHORT data as an array of chars (unsigned 16-bit
     * integers).
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_SHORT.
     */
    public char[] getAsChars() {
        return (char[])data;
    }

    /**
     * Returns TIFF_SSHORT data as an array of shorts (signed 16-bit
     * integers).
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_SSHORT.
     */
    public short[] getAsShorts() {
        return (short[])data;
    }

    /**
     * Returns TIFF_SLONG data as an array of ints (signed 32-bit
     * integers).
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_SLONG.
     */
    public int[] getAsInts() {
        return (int[])data;
    }

    /**
     * Returns TIFF_LONG data as an array of longs (signed 64-bit
     * integers).
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_LONG.
     */
    public long[] getAsLongs() {
        return (long[])data;
    }

    /**
     * Returns TIFF_FLOAT data as an array of floats. 
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_FLOAT.
     */
    public float[] getAsFloats() {
        return (float[])data;
    }

    /**
     * Returns TIFF_DOUBLE data as an array of doubles. 
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_DOUBLE.
     */
    public double[] getAsDoubles() {
        return (double[])data;
    }

    /**
     * Returns TIFF_SRATIONAL data as an array of 2-element arrays of ints.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_SRATIONAL.
     */
    public int[][] getAsSRationals() {
        return (int[][])data;
    }

    /**
     * Returns TIFF_RATIONAL data as an array of 2-element arrays of longs.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_RATTIONAL.
     */
    public long[][] getAsRationals() {
        return (long[][])data;
    }

    /**
     * Returns data in TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT,
     * TIFF_SSHORT, or TIFF_SLONG format as an int.
     *
     * <p> TIFF_BYTE and TIFF_UNDEFINED data are treated as unsigned;
     * that is, no sign extension will take place and the returned
     * value will be in the range [0, 255].  TIFF_SBYTE data will
     * be returned in the range [-128, 127].
     *
     * <p> A ClassCastException will be thrown if the field is not of
     * type TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT,
     * TIFF_SSHORT, or TIFF_SLONG.
     */
    public int getAsInt(int index) {
        switch (type) {
        case TIFF_BYTE: case TIFF_UNDEFINED:
            return ((byte[])data)[index] & 0xff;
        case TIFF_SBYTE:
            return ((byte[])data)[index];
        case TIFF_SHORT:
            return ((char[])data)[index] & 0xffff;
        case TIFF_SSHORT:
            return ((short[])data)[index];
        case TIFF_SLONG:
            return ((int[])data)[index];
        default:
            throw new ClassCastException();
        }
    }

    /**
     * Returns data in TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT,
     * TIFF_SSHORT, TIFF_SLONG, or TIFF_LONG format as a long.
     *
     * <p> TIFF_BYTE and TIFF_UNDEFINED data are treated as unsigned;
     * that is, no sign extension will take place and the returned
     * value will be in the range [0, 255].  TIFF_SBYTE data will
     * be returned in the range [-128, 127].
     *
     * <p> A ClassCastException will be thrown if the field is not of
     * type TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT,
     * TIFF_SSHORT, TIFF_SLONG, or TIFF_LONG.
     */
    public long getAsLong(int index) {
        switch (type) {
        case TIFF_BYTE: case TIFF_UNDEFINED:
            return ((byte[])data)[index] & 0xff;
        case TIFF_SBYTE:
            return ((byte[])data)[index];
        case TIFF_SHORT:
            return ((char[])data)[index] & 0xffff;
        case TIFF_SSHORT:
            return ((short[])data)[index];
        case TIFF_SLONG:
            return ((int[])data)[index];
        case TIFF_LONG:
            return ((long[])data)[index];
        default:
            throw new ClassCastException();
        }
    }
    
    /**
     * Returns data in any numerical format as a float.  Data in
     * TIFF_SRATIONAL or TIFF_RATIONAL format are evaluated by
     * dividing the numerator into the denominator using
     * double-precision arithmetic and then truncating to single
     * precision.  Data in TIFF_SLONG, TIFF_LONG, or TIFF_DOUBLE
     * format may suffer from truncation.
     *
     * <p> A ClassCastException will be thrown if the field is
     * of type TIFF_UNDEFINED or TIFF_ASCII.
     */
    public float getAsFloat(int index) {
        switch (type) {
        case TIFF_BYTE:
            return ((byte[])data)[index] & 0xff;
        case TIFF_SBYTE:
            return ((byte[])data)[index];
        case TIFF_SHORT:
            return ((char[])data)[index] & 0xffff;
        case TIFF_SSHORT:
            return ((short[])data)[index];
        case TIFF_SLONG:
            return ((int[])data)[index];
        case TIFF_LONG:
            return ((long[])data)[index];
        case TIFF_FLOAT:
            return ((float[])data)[index];
        case TIFF_DOUBLE:
            return (float)((double[])data)[index];
        case TIFF_SRATIONAL:
            int[] ivalue = getAsSRational(index);
            return (float)((double)ivalue[0]/ivalue[1]);
        case TIFF_RATIONAL:
            long[] lvalue = getAsRational(index);
            return (float)((double)lvalue[0]/lvalue[1]);
        default:
            throw new ClassCastException();
        }
    }

    /**
     * Returns data in any numerical format as a float.  Data in
     * TIFF_SRATIONAL or TIFF_RATIONAL format are evaluated by
     * dividing the numerator into the denominator using
     * double-precision arithmetic.
     *
     * <p> A ClassCastException will be thrown if the field is of
     * type TIFF_UNDEFINED or TIFF_ASCII.
     */
    public double getAsDouble(int index) {
        switch (type) {
        case TIFF_BYTE:
            return ((byte[])data)[index] & 0xff;
        case TIFF_SBYTE:
            return ((byte[])data)[index];
        case TIFF_SHORT:
            return ((char[])data)[index] & 0xffff;
        case TIFF_SSHORT:
            return ((short[])data)[index];
        case TIFF_SLONG:
            return ((int[])data)[index];
        case TIFF_LONG:
            return ((long[])data)[index];
        case TIFF_FLOAT:
            return ((float[])data)[index];
        case TIFF_DOUBLE:
            return ((double[])data)[index];
        case TIFF_SRATIONAL:
            int[] ivalue = getAsSRational(index);
            return (double)ivalue[0]/ivalue[1];
        case TIFF_RATIONAL:
            long[] lvalue = getAsRational(index);
            return (double)lvalue[0]/lvalue[1];
        default:
            throw new ClassCastException();
        }
    }

    /**
     * Returns a TIFF_ASCII data item as a String.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_ASCII.
     */
    public String getAsString(int index) {
        return ((String[])data)[index];
    }

    /**
     * Returns a TIFF_SRATIONAL data item as a two-element array
     * of ints.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_SRATIONAL.
     */
    public int[] getAsSRational(int index) {
        return ((int[][])data)[index];
    }

    /**
     * Returns a TIFF_RATIONAL data item as a two-element array
     * of ints.
     *
     * <p> A ClassCastException will be thrown if the field is not
     * of type TIFF_RATIONAL.
     */
    public long[] getAsRational(int index) {
        return ((long[][])data)[index];
    }

    /**
     * Compares this <code>TIFFField</code> with another
     * <code>TIFFField</code> by comparing the tags.
     *
     * <p><b>Note: this class has a natural ordering that is inconsistent
     * with <code>equals()</code>.</b>
     *
     * @throws IllegalArgumentException if the parameter is <code>null</code>.
     * @throws ClassCastException if the parameter is not a
     *         <code>TIFFField</code>.
     */
    public int compareTo(Object o) {
        if(o == null) {
            throw new IllegalArgumentException();
        }

        int oTag = ((TIFFField)o).getTag();

        if(tag < oTag) {
            return -1;
        } else if(tag > oTag) {
            return 1;
        } else {
            return 0;
        }
    }
}
