93 lines
2.6 KiB
Java
93 lines
2.6 KiB
Java
/*******************************************************************************
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* Copyright (c) 2002 - 2006 IBM Corporation.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* IBM Corporation - initial API and implementation
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*******************************************************************************/
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package com.ibm.wala.util.intset;
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import com.ibm.wala.util.debug.Trace;
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/**
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*
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* an int vector implementation designed for low occupancy. Note that get() from
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* this vector is a binary search.
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*
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* This should only be used for small sets ... insertion and deletion are linear
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* in size of set.
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*
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* @author sfink
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*/
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public class SparseIntVector implements IntVector {
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private final static int INITIAL_SIZE = 5;
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private final double EXPANSION = 1.5;
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/**
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* if indices[i] = x, then data[i] == get(x)
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*/
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private MutableSparseIntSet indices = new MutableSparseIntSet();
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private int[] data = new int[INITIAL_SIZE];
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private final int defaultValue;
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SparseIntVector(int defaultValue) {
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this.defaultValue = defaultValue;
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}
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/*
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* (non-Javadoc)
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*
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* @see com.ibm.wala.util.intset.IntVector#get(int)
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*/
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public int get(int x) {
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int index = indices.getIndex(x);
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if (index == -1) {
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return defaultValue;
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} else {
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return data[index];
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}
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}
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/*
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* TODO: this can be optimized (non-Javadoc)
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*
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* @see com.ibm.wala.util.intset.IntVector#set(int, int)
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*/
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public void set(int x, int value) {
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int index = indices.getIndex(x);
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if (index == -1) {
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indices.add(x);
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index = indices.getIndex(x);
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ensureCapacity(indices.size() + 1);
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if (index < (data.length - 1)) {
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System.arraycopy(data, index, data, index + 1, indices.size() - index);
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}
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}
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data[index] = value;
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}
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private void ensureCapacity(int capacity) {
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if (data.length < capacity + 1) {
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int[] old = data;
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data = new int[1 + (int) (capacity * EXPANSION)];
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System.arraycopy(old, 0, data, 0, old.length);
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}
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}
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/*
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* (non-Javadoc)
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*
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* @see com.ibm.wala.util.debug.VerboseAction#performVerboseAction()
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*/
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public void performVerboseAction() {
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Trace.println(getClass() + " stats: ");
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Trace.println("data.length " + data.length);
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Trace.println("indices.size() " + indices.size());
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}
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} |