128 lines
3.5 KiB
Java
128 lines
3.5 KiB
Java
/**
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*******************************************************************************
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* Copyright (C) 1996-2001, International Business Machines Corporation and *
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* others. All Rights Reserved. *
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*******************************************************************************
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*
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* $Source: /xsrl/Nsvn/icu/unicodetools/com/ibm/text/utility/IntStack.java,v $
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* $Date: 2002/06/15 02:47:14 $
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* $Revision: 1.4 $
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*
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*******************************************************************************
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*/
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package com.ibm.text.utility;
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// =============================================================
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// Simple stack mechanism, with push, pop and access
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// =============================================================
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public final class IntStack implements Comparable, Cloneable {
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private int[] values;
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private int top = 0;
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private int first = 0;
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public IntStack(int initialSize) {
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values = new int[initialSize];
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}
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public IntStack append(IntStack other) {
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// TODO speed up by copying arrays
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for (int i = 0; i < other.getTop(); ++i) {
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push(other.get(i));
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}
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return this;
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}
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public IntStack append(int value) {
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return push(value);
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}
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public int length() {
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return top - first;
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}
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public IntStack push(int value) {
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if (top >= values.length) { // must grow?
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int[] temp = new int[values.length*2];
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System.arraycopy(values,0,temp,0,values.length);
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values = temp;
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}
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values[top++] = value;
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return this;
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}
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public int pop() {
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if (top > first) {
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int result = values[--top];
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if (top == first && first > 0) {
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top = first = 0;
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}
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return result;
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}
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throw new IllegalArgumentException("Stack underflow");
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}
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public int popFront() {
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if (top > first) {
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int result = values[first++];
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if (top == first) {
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top = first = 0;
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}
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return result;
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}
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throw new IllegalArgumentException("Stack underflow");
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}
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public int get(int index) {
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if (first <= index && index < top) return values[index];
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throw new IllegalArgumentException("Stack index out of bounds");
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}
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public int getTop() {
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return top;
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}
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public boolean isEmpty() {
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return top - first == 0;
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}
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public void clear() {
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top = first = 0;
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}
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public int compareTo(Object other) {
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IntStack that = (IntStack) other;
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int myLen = top - first;
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int thatLen = that.top - that.first;
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int limit = first + ((myLen < thatLen) ? myLen : thatLen);
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int delta = that.first - first;
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for (int i = first; i < limit; ++i) {
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int result = values[i] - that.values[i + delta];
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if (result != 0) return result;
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}
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return myLen - thatLen;
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}
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public boolean equals(Object other) {
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return compareTo(other) == 0;
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}
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public int hashCode() {
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int result = top;
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for (int i = first; i < top; ++i) {
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result = result * 37 + values[i];
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}
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return result;
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}
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public Object clone() {
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try {
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IntStack result = (IntStack) (super.clone());
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result.values = (int[]) result.values.clone();
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return result;
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} catch (CloneNotSupportedException e) {
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throw new IllegalArgumentException("Will never happen");
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}
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}
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} |