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112 lines
2.0 KiB
112 lines
2.0 KiB
//
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// Stack.cc
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//
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// Stack: This class implements a linked list of objects. It itself is also an
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// object
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//
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// Part of the ht://Dig package <http://www.htdig.org/>
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// Copyright (c) 1999-2004 The ht://Dig Group
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// For copyright details, see the file COPYING in your distribution
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// or the GNU Library General Public License (LGPL) version 2 or later
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// <http://www.gnu.org/copyleft/lgpl.html>
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//
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// $Id: Stack.cc,v 1.5 2004/05/28 13:15:21 lha Exp $
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//
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#ifdef HAVE_CONFIG_H
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#include "htconfig.h"
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#endif /* HAVE_CONFIG_H */
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#include "Stack.h"
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struct stacknode
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{
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stacknode *next;
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Object *obj;
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};
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//***************************************************************************
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// Stack::Stack()
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//
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Stack::Stack()
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{
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sp = 0;
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size = 0;
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}
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//***************************************************************************
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// Stack::~Stack()
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//
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Stack::~Stack()
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{
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while (sp)
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{
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Object *obj = pop();
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delete obj;
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}
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}
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//***************************************************************************
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// void Stack::destroy()
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//
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void Stack::destroy()
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{
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while (sp)
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{
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Object *obj = pop();
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delete obj;
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}
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}
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//***************************************************************************
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// void Stack::push(Object *obj)
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// PURPOSE:
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// Push an object onto the stack.
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//
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void Stack::push(Object *obj)
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{
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stacknode *node = new stacknode;
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node->obj = obj;
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node->next = (stacknode *) sp;
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sp = node;
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size++;
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}
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//***************************************************************************
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// Object *Stack::pop()
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// PURPOSE:
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// Return the object at the top of the stack and remove it from the stack.
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//
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Object *Stack::pop()
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{
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if (size == 0)
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return 0;
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stacknode *node = (stacknode *) sp;
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Object *obj = node->obj;
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sp = (void *) node->next;
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delete node;
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size--;
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return obj;
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}
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//***************************************************************************
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// Object *Stack::peek()
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// PURPOSE:
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// Return the object at the top of the stack.
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//
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Object *Stack::peek()
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{
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if (size == 0)
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return 0;
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return ((stacknode *)sp)->obj;
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}
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