/* SetOfIntegerSyntax.java -- 
   Copyright (C) 2003, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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this exception to your version of the library, but you are not
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package javax.print.attribute;

import java.io.Serializable;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;

/**
 * <code>SetOfIntegerSyntax</code> is the abstract base class of all attribute 
 * classes which provide a set of non-negative integers as value (e.g. the
 * page ranges to print) represented as single values or ranges of values.
 * <p>
 * A <code>SetOfIntegerSyntax</code> instance consists of an integer array of
 * ranges. Ranges may have the same lower and upper bound representing a single
 * integer value. Ranges with a lower bound greater than the upper bound are 
 * null ranges and discarded. Ranges may overlap in their values. In no case 
 * negative integers are allowed.
 * </p>
 * <p>
 * There are several constructors available:
 * <ul>
 * <li><code>SetOfIntegerSyntax(int member)</code><br>
 * Constructor for an instance with only one integer value.
 * </li><br>
 * <li><code>SetOfIntegerSyntax(int lowerBound, int upperBound)</code><br>
 * Constructor for an instance with one range of integer values.
 * </li><br>
 * <li><code>SetOfIntegerSyntax(int[][] members)</code><br>
 * Flexible constructor for an instance with several single integer values 
 * and/or several ranges of integer values. The allowed array form is an 
 * array of integer arrays of length one or two. Examples are: 
 * <code>int[0][]</code> for empty set of integers, <code>int[][] {{1}}</code>
 * , <code>int[][] {{1,5}}</code>, <code>int[][] {{1,5},{7,9}}</code>,
 * <code>int[][] {{3,7},{19}}</code>.
 * </li><br>
 * <li><code>SetOfIntegerSyntax(String s)</code><br>
 * Flexible constructor for an instance with several single integer values 
 * and/or several ranges of integer values. The allowed String instance have
 * to be a String with comma separated ranges of integer values or single 
 * values. Ranges are represented by two integer with a hypen (-) or colon (:)
 * between the lower and upper bound value. Whitespace characters are ignored.
 * Examples are: <code>""</code> for an empty set of integers, 
 * <code>"1"</code>, <code>"1-5"</code>, <code>"1-5,7-9"</code>, 
 * <code>"3-7,19"</code> and <code>"1:2,4"</code>.
 * </li>
 * </ul>
 * </p>
 * <p>
 * <b>Internal storage:</b><br>
 * The set of integers are stored internally in a normalized array form.
 * In the normalized array form the set of integer ranges are represented
 * in as few ranges as possible and overlapping ranges are merged. The ranges 
 * are always represented as an integer array of length two with ranges 
 * stored in {lower bound, upper bound} form. The ranges are stored in 
 * ascending order, without any null ranges.
 * </p>
 * @author Michael Koch (konqueror@gmx.de)
 */
public abstract class SetOfIntegerSyntax
  implements Cloneable, Serializable
{
  private static final long serialVersionUID = 3666874174847632203L;

  private int[][] members;

  private static int[][] normalize(int[][] values, int size)
  {
    // Sort into increasing order.  First the first index is
    // compared, then the second.
    Arrays.sort(values, 0, size, new Comparator()
                {
                  public int compare(Object o1, Object o2)
                  {
                    int[] v1 = (int[]) o1;
                    int[] v2 = (int[]) o2;
                    if (v1[0] == v2[0])
                      return v1[1] - v2[1];
                    return v1[0] - v2[0];
                  }
                });

    // Now coalesce overlapping ranges.
    int outIndex = 0;
    for (int i = 0; i < size; ++i)
      {
        // Note that we compare with values[i][1]+1, since
        // we can coalesce {0,1} with {2,x}.
        int save = i;
        while (i + 1 < size && values[i + 1][0] <= values[i][1] + 1)
          {
            values[i][1] = Math.max(values[i][1], values[i + 1][1]);
            ++i;
          }
        values[outIndex++] = values[save];
      }
    
    int[][] result = new int[outIndex][];
    System.arraycopy(values, 0, result, 0, outIndex);
    
    return result;
  }
  
  /**
   * Creates a <code>SetOfIntegerSyntax</code> object.
   *
   * @param member the member value
   *
   * @exception IllegalArgumentException if member is &lt; 0
   */
  protected SetOfIntegerSyntax(int member)
  {
    if (member < 0)
      throw new IllegalArgumentException("member may not be less than 0");

    this.members = new int[][]{{member, member}};
  }

  /**
   * Creates a <code>SetOfIntegerSyntax</code> object.
   *
   * @param members the members to use in this set. If
   * <code>null</code> an empty set is created.
   *
   * @exception IllegalArgumentException if any element is invalid
   * @exception NullPointerException if any element of members is null
   */
  protected SetOfIntegerSyntax(int[][] members)
  {
    int[][] newMembers;
    int outIndex = 0;
    if (members == null)
      newMembers = new int[0][];
    else
      {
        newMembers = new int[members.length][];
        for (int index = 0; index < members.length; index++)
          {
            int lower;
            int upper;

            if (members[index].length == 1)
              {
                lower = members[index][0];
                upper = members[index][0];
              }
            else if (members[index].length == 2)
              {
                lower = members[index][0];
                upper = members[index][1];
              }
            else
              throw new IllegalArgumentException("invalid member element");

            // We only want to reject non-null ranges where lower<0.
            if (lower <= upper && lower < 0)
              throw new IllegalArgumentException("invalid member element");

            if (lower <= upper)
              {
                int[] range = new int[2];
                range[0] = lower;
                range[1] = upper;
                newMembers[outIndex++] = range;
              }
          }
      }
    
    this.members = normalize(newMembers, outIndex);
  }
  
  private boolean skipWhitespace(StringCharacterIterator i)
  {
    while (Character.isWhitespace(i.current()))
      i.next();
    return i.current() == CharacterIterator.DONE;
  }
  
  private boolean skipNumber(StringCharacterIterator i)
  {
    boolean readAny = false;
    while (Character.isDigit(i.current()))
      {
        readAny = true;
        i.next();
      }
    return readAny;
  }

  /**
   * Creates a <code>SetOfIntegerSyntax</code> object.
   *
   * @param s the members to use in this set in string form. If
   * <code>null</code> an empty set is created.
   *
   * @exception IllegalArgumentException if any element is invalid
   */
  protected SetOfIntegerSyntax(String s)
  {
    if (s == null)
      this.members = normalize(new int[0][], 0);
    else
      {      
        ArrayList vals = new ArrayList();
        
        StringCharacterIterator it = new StringCharacterIterator(s);
        
        while (true)
          {
            // Skip whitespace.
            if (skipWhitespace(it))
              break;
            
            // Parse integer.
            int index = it.getIndex();
            if (! skipNumber(it))
              throw new IllegalArgumentException();
            int[] item = new int[2];
            item[0] = Integer.parseInt(s.substring(index, it.getIndex()));
            
            if (! skipWhitespace(it))
              {
                char c = it.current();
                if (c == ':' || c == '-')
                  {
                  it.next();
                  if (skipWhitespace(it))
                    throw new IllegalArgumentException();
                  index = it.getIndex();
                  if (! skipNumber(it))
                    throw new IllegalArgumentException();
                  item[1] = Integer.parseInt(s.substring(index, it.getIndex()));
                  }
                else
                  item[1] = item[0];
              }
            else
              item[1] = item[0];
            
            if (item[0] <= item[1]) 
              vals.add(item);
            
            if (skipWhitespace(it))
              break;
            if (it.current() != ',')
              throw new IllegalArgumentException();
            it.next();
          }
        
        members = normalize((int[][]) vals.toArray(new int[0][]), vals.size());
      }
  }

  /**
   * Creates a <code>SetOfIntegerSyntax</code> object.
   *
   * @param lowerBound the lower bound value
   * @param upperBound the upper bound value
   *
   * @exception IllegalArgumentException if lowerBound &lt;= upperbound
   * and lowerBound &lt; 0
   */
  protected SetOfIntegerSyntax(int lowerBound, int upperBound)
  {
    // We only want to reject non-null ranges where lower<0.
    if (lowerBound <= upperBound
        && lowerBound < 0)
      throw new IllegalArgumentException();

    members = (lowerBound <= upperBound ? new int[][]{{lowerBound, upperBound}}
                                        : new int[0][]);
  }

  /**
   * Checks if this set contains the given value.
   *
   * @param value the value to test for
   *
   * @return true if this set contains value, false otherwise
   */
  public boolean contains(int value)
  {
    // This only works on a normalized member array.
    for (int index = 0; index < members.length; index++)
      {
        if (value < members[index][0])
          return false;
        else if (value <= members[index][1])
          return true;
      }

    return false;
  }

  /**
   * Checks if this set contains the given value.
   *
   * @param value the value to test for
   *
   * @return true if this set contains value, false otherwise
   */
  public boolean contains(IntegerSyntax value)
  {
    return contains(value.getValue());
  }

  /**
   * Tests if the given object is equal to this object.
   *
   * @param obj the object to test
   *
   * @return true if both objects are equal, false otherwise.
   */
  public boolean equals(Object obj)
  {
    if (! (obj instanceof SetOfIntegerSyntax))
      return false;
    SetOfIntegerSyntax other = (SetOfIntegerSyntax) obj;
    if (other.members.length != members.length)
      return false;
    for (int i = 0; i < members.length; ++i)
      {
        if (members[i][0] != other.members[i][0]
            || members[i][1] != other.members[i][1])
          return false;
      }
    return true;
  }

  /**
   * Returns an array describing the members included in this set.
   *
   * @return The members in normalized array form.
   */
  public int[][] getMembers()
  {
    return (int[][]) members.clone();
  }

  /**
   * Returns the hashcode for this object.
   *
   * @return The hashcode.
   */
  public int hashCode()
  {
    int result = 0;
    for (int i = 0; i < members.length; ++i)
      result += members[i][0] + members[i][1];
    return result;
  }

  /**
   * Returns the smallest value that is greater than x which is in this set.
   *
   * @param x an integer value
   *
   * @return The next smallest integer value, or <code>-1</code> if there 
   * is no greater integer in the set.
   */
  public int next(int x)
  {
    for (int i = 0; i < members.length; ++i)
      {
        if (x >= members[i][1])
          continue;
        if (x < members[i][0])
          return members[i][0];
        // X is in this range.
        return x + 1;
      }
    return -1;
  }

  /**
   * Returns the string representation for this object.
   * The value is a zero length string for an empty set, or a comma seperated
   * list of ranges and single values in the form <code>"1-2,5-7,10"</code>.
   *
   * @return The string representation.
   */
  public String toString()
  {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < members.length; ++i)
      {
        if (i > 0)
          sb.append(',');
        sb.append(members[i][0]);
        if (members[i][0] != members[i][1])
          {
            sb.append('-');
            sb.append(members[i][1]);
          }
      }
    return sb.toString();
  }
}