/*
 *                 Sun Public License Notice
 * 
 * The contents of this file are subject to the Sun Public License
 * Version 1.0 (the "License"). You may not use this file except in
 * compliance with the License. A copy of the License is available at
 * http://www.sun.com/
 * 
 * The Original Code is NetBeans. The Initial Developer of the Original
 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2004 Sun
 * Microsystems, Inc. All Rights Reserved.
 */
/*
 * IntMap.java
 *
 * Created on March 29, 2004, 6:40 PM
 */

package org.netbeans.core.output2;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

/**
 * Sparse array integer keyed map.  Similar to a standard Collections map,
 * but considerably more efficient for this purpose, it simply an array 
 * if integer indices that have values and an array of objects mapped to
 * those indices.  Entries may be added only in ascending order, enabling
 * use of Arrays.binarySearch() to quickly locate the relevant entry.
 * 

 * Used to maintain the mapping between the (relatively few) OutputListeners
 * and their associated getLine numbers.
 *
 * @author  Tim Boudreau
 */
final class IntMap {
    private int[] keys = new int[] { Integer.MAX_VALUE, Integer.MAX_VALUE, 
        Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
        
    private Object[] vals = new Object[5];
    private int last = -1;
    
    /** Creates a new instance of IntMap */
    IntMap() {
    }
    
    public int first() {
        return isEmpty() ? -1 : keys[0];
    }
    
    public int nearest (int line, boolean backward) {
        if (isEmpty()) {
            return -1;
        }
        if (last == 0) {
            return keys[last];
        }
        if (line < keys[0]) {
            return backward ? keys[last] : keys[0];
        }
        if (line > keys[last]) {
            return backward ? keys[last] : keys[0];
        }
        int idx = Arrays.binarySearch (keys, line);
        if (idx < 0) {
            for (int i=1; i <= last; i++) {
                if (keys[i-1] < line && keys[i] > line) {
                    idx = i;
                    break;
                }
            }
            return backward ? keys[idx-1] : keys[idx];
        } else {
            if (backward) {
                idx = idx == 0 ? last : idx - 1;
            } else {
                idx = idx == last ? 0 : idx + 1;
            }
            return keys[idx];
        }
    }

    public int[] getKeys () {
        int[] result = new int[last+1];
        System.arraycopy (keys, 0, result, 0, last+1);
        return result;
    }
    
    public Object get (int key) {
        int idx = Arrays.binarySearch (keys, key);
        if (idx > -1 && idx <= last) {
            return vals[idx];
        }
        return null;
    }
    
    public void put (int key, Object val) {
        if (last > 0) {
            assert key > keys[last];
        }
        if (last == keys.length - 1) {
            growArrays();
        }
        last++;
        keys[last] = key;
        vals[last] = val;
    }
    
    private void growArrays() {
        int newSize = last * 2;
        int[] newKeys = new int[newSize];
        Object[] newVals = new Object[newSize];
        Arrays.fill (newKeys, Integer.MAX_VALUE); //So binarySearch works
        System.arraycopy (keys, 0, newKeys, 0, keys.length);
        System.arraycopy (vals, 0, newVals, 0, vals.length);
        keys = newKeys;
        vals = newVals;
    }
    
    /**
     * Get the key which follows the passed key, or -1.  Will wrap around 0.
     */
    public int nextEntry (int entry) {
        int result = -1;
        if (!isEmpty()) {
            int idx = Arrays.binarySearch (keys, entry);
            if (idx >= 0) {
                result = idx == keys.length -1 ? keys[0] : keys[idx+1];
            }
        }
        return result;
    }
    
    /**
     * Get the key which precedes the passed key, or -1.  Will wrap around 0.
     */
    public int prevEntry (int entry) {
        int result = -1;
        if (!isEmpty()) {
            int idx = Arrays.binarySearch (keys, entry);
            if (idx >= 0) {
                result = idx == 0 -1 ? keys[keys.length-1] : keys[idx-1];
            }
        }
        return result;
    }
    
    
    public boolean isEmpty() {
        return last == -1;
    }
    
    public int size() {
        return last + 1;
    }
    
    public String toString() {
        StringBuffer sb = new StringBuffer("IntMap@" + 
            System.identityHashCode(this)); //NOI18N
        
        for (int i=0; i < size(); i++) {
            sb.append ("["); //NOI18N
            sb.append (keys[i]);
            sb.append (":"); //NOI18N
            sb.append (vals[i]);
            sb.append ("]"); //NOI18N
        }
        if (size() == 0) {
            sb.append ("empty"); //NOI18N
        }
        return sb.toString();
    }
}