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      1 /*
      2  [The "BSD licence"]
      3  Copyright (c) 2005-2008 Terence Parr
      4  All rights reserved.
      5 
      6  Redistribution and use in source and binary forms, with or without
      7  modification, are permitted provided that the following conditions
      8  are met:
      9  1. Redistributions of source code must retain the above copyright
     10     notice, this list of conditions and the following disclaimer.
     11  2. Redistributions in binary form must reproduce the above copyright
     12     notice, this list of conditions and the following disclaimer in the
     13     documentation and/or other materials provided with the distribution.
     14  3. The name of the author may not be used to endorse or promote products
     15     derived from this software without specific prior written permission.
     16 
     17  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     18  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 */
     28 package org.antlr.runtime.misc;
     29 
     30 /** A dynamic array that uses int not Integer objects. In principle this
     31  *  is more efficient in time, but certainly in space.
     32  *
     33  *  This is simple enough that you can access the data array directly,
     34  *  but make sure that you append elements only with add() so that you
     35  *  get dynamic sizing.  Make sure to call ensureCapacity() when you are
     36  *  manually adding new elements.
     37  *
     38  *  Doesn't impl List because it doesn't return objects and I mean this
     39  *  really as just an array not a List per se.  Manipulate the elements
     40  *  at will.  This has stack methods too.
     41  *
     42  *  When runtime can be 1.5, I'll make this generic.
     43  */
     44 public class IntArray {
     45 	public static final int INITIAL_SIZE = 10;
     46 	public int[] data;
     47 	protected int p = -1;
     48 
     49 	public void add(int v) {
     50 		ensureCapacity(p+1);
     51 		data[++p] = v;
     52 	}
     53 
     54 	public void push(int v) {
     55 		add(v);
     56 	}
     57 
     58 	public int pop() {
     59 		int v = data[p];
     60 		p--;
     61 		return v;
     62 	}
     63 
     64 	/** This only tracks elements added via push/add. */
     65 	public int size() {
     66 		return p;
     67 	}
     68 
     69     public void clear() {
     70         p = -1;
     71     }
     72 
     73     public void ensureCapacity(int index) {
     74 		if ( data==null ) {
     75 			data = new int[INITIAL_SIZE];
     76 		}
     77 		else if ( (index+1)>=data.length ) {
     78 			int newSize = data.length*2;
     79 			if ( index>newSize ) {
     80 				newSize = index+1;
     81 			}
     82 			int[] newData = new int[newSize];
     83 			System.arraycopy(data, 0, newData, 0, data.length);
     84 			data = newData;
     85 		}
     86 	}
     87 }
     88