// IntHashtable - a Hashtable that uses ints as the keys//// This is 90% based on JavaSoft's java.util.Hashtable.//// Visit the ACME Labs Java page for up-to-date versions of this and other// fine Java utilities: http://www.acme.com/java/package com.lowagie.text.pdf;import java.util.Arrays;/// A Hashtable that uses ints as the keys.// <P>// Use just like java.util.Hashtable, except that the keys must be ints.// This is much faster than creating a new Integer for each access.// <P>// <A HREF="/resources/classes/Acme/IntHashtable.java">Fetch the software.</A><BR>// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>// <P>// @see java.util.Hashtablepublic class IntHashtable {    /// The hash table data.    private IntHashtableEntry table[];        /// The total number of entries in the hash table.    private int count;        /// Rehashes the table when count exceeds this threshold.    private int threshold;        /// The load factor for the hashtable.    private float loadFactor;        /// Constructs a new, empty hashtable with the specified initial    // capacity and the specified load factor.    // @param initialCapacity the initial number of buckets    // @param loadFactor a number between 0.0 and 1.0, it defines    //		the threshold for rehashing the hashtable into    //		a bigger one.    // @exception IllegalArgumentException If the initial capacity    // is less than or equal to zero.    // @exception IllegalArgumentException If the load factor is    // less than or equal to zero.    public IntHashtable( int initialCapacity, float loadFactor ) {        if ( initialCapacity <= 0 || loadFactor <= 0.0 )            throw new IllegalArgumentException();        this.loadFactor = loadFactor;        table = new IntHashtableEntry[initialCapacity];        threshold = (int) ( initialCapacity * loadFactor );    }        /// Constructs a new, empty hashtable with the specified initial    // capacity.    // @param initialCapacity the initial number of buckets    public IntHashtable( int initialCapacity ) {        this( initialCapacity, 0.75f );    }        /// Constructs a new, empty hashtable. A default capacity and load factor    // is used. Note that the hashtable will automatically grow when it gets    // full.    public IntHashtable() {        this( 101, 0.75f );    }        /// Returns the number of elements contained in the hashtable.    public int size() {        return count;    }        /// Returns true if the hashtable contains no elements.    public boolean isEmpty() {        return count == 0;    }        /// Returns true if the specified object is an element of the hashtable.    // This operation is more expensive than the containsKey() method.    // @param value the value that we are looking for    // @exception NullPointerException If the value being searched    // for is equal to null.    // @see IntHashtable#containsKey    public boolean contains( int value ) {        IntHashtableEntry tab[] = table;        for ( int i = tab.length ; i-- > 0 ; ) {            for ( IntHashtableEntry e = tab[i] ; e != null ; e = e.next ) {                if ( e.value == value )                    return true;            }        }        return false;    }        /// Returns true if the collection contains an element for the key.    // @param key the key that we are looking for    // @see IntHashtable#contains    public boolean containsKey( int key ) {        IntHashtableEntry tab[] = table;        int hash = key;        int index = ( hash & 0x7FFFFFFF ) % tab.length;        for ( IntHashtableEntry e = tab[index] ; e != null ; e = e.next ) {            if ( e.hash == hash && e.key == key )                return true;        }        return false;    }        /// Gets the object associated with the specified key in the    // hashtable.    // @param key the specified key    // @returns the element for the key or null if the key    // 		is not defined in the hash table.    // @see IntHashtable#put    public int get( int key ) {        IntHashtableEntry tab[] = table;        int hash = key;        int index = ( hash & 0x7FFFFFFF ) % tab.length;        for ( IntHashtableEntry e = tab[index] ; e != null ; e = e.next ) {            if ( e.hash == hash && e.key == key )                return e.value;        }        return 0;    }        /// Rehashes the content of the table into a bigger table.    // This method is called automatically when the hashtable's    // size exceeds the threshold.    protected void rehash() {        int oldCapacity = table.length;        IntHashtableEntry oldTable[] = table;                int newCapacity = oldCapacity * 2 + 1;        IntHashtableEntry newTable[] = new IntHashtableEntry[newCapacity];                threshold = (int) ( newCapacity * loadFactor );        table = newTable;                for ( int i = oldCapacity ; i-- > 0 ; ) {            for ( IntHashtableEntry old = oldTable[i] ; old != null ; ) {                IntHashtableEntry e = old;                old = old.next;                                int index = ( e.hash & 0x7FFFFFFF ) % newCapacity;                e.next = newTable[index];                newTable[index] = e;            }        }    }        /// Puts the specified element into the hashtable, using the specified    // key.  The element may be retrieved by doing a get() with the same key.    // The key and the element cannot be null.    // @param key the specified key in the hashtable    // @param value the specified element    // @exception NullPointerException If the value of the element    // is equal to null.    // @see IntHashtable#get    // @return the old value of the key, or null if it did not have one.    public int put( int key, int value ) {        // Makes sure the key is not already in the hashtable.        IntHashtableEntry tab[] = table;        int hash = key;        int index = ( hash & 0x7FFFFFFF ) % tab.length;        for ( IntHashtableEntry e = tab[index] ; e != null ; e = e.next ) {            if ( e.hash == hash && e.key == key ) {                int old = e.value;                e.value = value;                return old;            }        }                if ( count >= threshold ) {            // Rehash the table if the threshold is exceeded.            rehash();            return put( key, value );        }                // Creates the new entry.        IntHashtableEntry e = new IntHashtableEntry();        e.hash = hash;        e.key = key;        e.value = value;        e.next = tab[index];        tab[index] = e;        ++count;        return 0;    }        /// Removes the element corresponding to the key. Does nothing if the    // key is not present.    // @param key the key that needs to be removed    // @return the value of key, or null if the key was not found.    public int remove( int key ) {        IntHashtableEntry tab[] = table;        int hash = key;        int index = ( hash & 0x7FFFFFFF ) % tab.length;        for ( IntHashtableEntry e = tab[index], prev = null ; e != null ; prev = e, e = e.next ) {            if ( e.hash == hash && e.key == key ) {                if ( prev != null )                    prev.next = e.next;                else                    tab[index] = e.next;                --count;                return e.value;            }        }        return 0;    }        /// Clears the hash table so that it has no more elements in it.    public void clear() {        IntHashtableEntry tab[] = table;        for ( int index = tab.length; --index >= 0; )            tab[index] = null;        count = 0;    }        public int[] toOrderedKeys() {        int res[] = new int[count];        int ptr = 0;        int index = table.length;        IntHashtableEntry entry = null;        while (true) {            if (entry == null)                while ((index-- > 0) && ((entry = table[index]) == null));            if (entry == null)                break;            IntHashtableEntry e = entry;            entry = e.next;            res[ptr++] = e.key;        }        Arrays.sort(res);        return res;    }        class IntHashtableEntry {        int hash;        int key;        int value;        IntHashtableEntry next;    }    }