mirror of
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377 lines
9.5 KiB
C++
377 lines
9.5 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* MODULE NOTES:
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*
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* The Deque is a very small, very efficient container object
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* than can hold elements of type void*, offering the following features:
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* Its interface supports pushing and popping of elements.
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* It can iterate (via an interator class) its elements.
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* When full, it can efficiently resize dynamically.
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*
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*
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* NOTE: The only bit of trickery here is that this deque is
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* built upon a ring-buffer. Like all ring buffers, the first
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* element may not be at index[0]. The mOrigin member determines
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* where the first child is. This point is quietly hidden from
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* customers of this class.
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*
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*/
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#ifndef _NSDEQUE
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#define _NSDEQUE
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#include "nscore.h"
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/**
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* The nsDequeFunctor class is used when you want to create
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* callbacks between the deque and your generic code.
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* Use these objects in a call to ForEach();
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*
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*/
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class nsDequeFunctor{
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public:
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virtual void* operator()(void* anObject)=0;
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};
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/******************************************************
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* Here comes the nsDeque class itself...
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******************************************************/
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/**
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* The deque (double-ended queue) class is a common container type,
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* whose behavior mimics a line in your favorite checkout stand.
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* Classic CS describes the common behavior of a queue as FIFO.
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* A deque allows insertion and removal at both ends of
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* the container.
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*
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* The deque stores pointers to items.
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*/
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class nsDequeIterator;
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class NS_COM_GLUE nsDeque {
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friend class nsDequeIterator;
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public:
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nsDeque(nsDequeFunctor* aDeallocator = nsnull);
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~nsDeque();
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/**
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* Returns the number of elements currently stored in
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* this deque.
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*
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* @return number of elements currently in the deque
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*/
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inline PRInt32 GetSize() const {return mSize;}
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/**
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* Appends new member at the end of the deque.
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*
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* @param item to store in deque
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* @return *this
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*/
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nsDeque& Push(void* aItem);
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/**
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* Inserts new member at the front of the deque.
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*
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* @param item to store in deque
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* @return *this
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*/
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nsDeque& PushFront(void* aItem);
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/**
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* Remove and return the last item in the container.
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*
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* @return the item that was the last item in container
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*/
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void* Pop();
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/**
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* Remove and return the first item in the container.
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*
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* @return the item that was first item in container
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*/
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void* PopFront();
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/**
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* Retrieve the bottom item without removing it.
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*
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* @return the first item in container
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*/
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void* Peek();
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/**
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* Return topmost item without removing it.
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*
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* @return the first item in container
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*/
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void* PeekFront();
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/**
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* Retrieve the i'th member from the deque without removing it.
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*
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* @param index of desired item
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* @return i'th element in list
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*/
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void* ObjectAt(int aIndex) const;
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/**
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* Removes and returns the i'th member from the deque.
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*
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* @param index of desired item
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* @return the element which was removed
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*/
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void* RemoveObjectAt(int aIndex);
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/**
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* Remove all items from container without destroying them.
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*
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* @return *this
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*/
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nsDeque& Empty();
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/**
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* Remove and delete all items from container.
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* Deletes are handled by the deallocator nsDequeFunctor
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* which is specified at deque construction.
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*
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* @return *this
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*/
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nsDeque& Erase();
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/**
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* Creates a new iterator, pointing to the first
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* item in the deque.
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*
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* @return new dequeIterator
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*/
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nsDequeIterator Begin() const;
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/**
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* Creates a new iterator, pointing to the last
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* item in the deque.
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*
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* @return new dequeIterator
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*/
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nsDequeIterator End() const;
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void* Last() const;
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/**
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* Call this method when you want to iterate all the
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* members of the container, passing a functor along
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* to call your code.
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*
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* @param aFunctor object to call for each member
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* @return *this
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*/
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void ForEach(nsDequeFunctor& aFunctor) const;
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/**
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* Call this method when you want to iterate all the
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* members of the container, calling the functor you
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* passed with each member. This process will interrupt
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* if your function returns non 0 to this method.
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*
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* @param aFunctor object to call for each member
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* @return first nonzero result of aFunctor or 0.
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*/
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const void* FirstThat(nsDequeFunctor& aFunctor) const;
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void SetDeallocator(nsDequeFunctor* aDeallocator);
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protected:
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PRInt32 mSize;
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PRInt32 mCapacity;
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PRInt32 mOrigin;
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nsDequeFunctor* mDeallocator;
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void* mBuffer[8];
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void** mData;
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private:
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/**
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* Copy constructor (PRIVATE)
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*
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* @param another deque
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*/
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nsDeque(const nsDeque& other);
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/**
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* Deque assignment operator (PRIVATE)
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*
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* @param another deque
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* @return *this
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*/
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nsDeque& operator=(const nsDeque& anOther);
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bool GrowCapacity();
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};
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/******************************************************
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* Here comes the nsDequeIterator class...
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******************************************************/
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class NS_COM_GLUE nsDequeIterator {
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public:
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/**
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* DequeIterator is an object that knows how to iterate
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* (forward and backward) through a Deque. Normally,
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* you don't need to do this, but there are some special
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* cases where it is pretty handy.
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*
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* One warning: the iterator is not bound to an item,
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* it is bound to an index, so if you insert or remove
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* from the beginning while using an iterator
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* (which is not recommended) then the iterator will
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* point to a different item. @see GetCurrent()
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*
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* Here you go.
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*
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* @param aQueue is the deque object to be iterated
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* @param aIndex is the starting position for your iteration
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*/
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nsDequeIterator(const nsDeque& aQueue, int aIndex=0);
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/**
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* Create a copy of a DequeIterator
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*
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* @param aCopy is another iterator to copy from
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*/
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nsDequeIterator(const nsDequeIterator& aCopy);
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/**
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* Moves iterator to first element in the deque
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* @return *this
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*/
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nsDequeIterator& First();
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/**
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* Standard assignment operator for dequeiterator
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* @param aCopy is another iterator to copy from
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* @return *this
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*/
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nsDequeIterator& operator=(const nsDequeIterator& aCopy);
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/**
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* preform ! operation against two iterators to test for equivalence
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* (or lack thereof)!
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*
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* @param aIter is the object to be compared to
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* @return TRUE if NOT equal.
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*/
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bool operator!=(nsDequeIterator& aIter);
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/**
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* Compare two iterators for increasing order.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if this object points to an element before
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* the element pointed to by aIter.
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* FALSE if this and aIter are not iterating over
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* the same deque.
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*/
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bool operator<(nsDequeIterator& aIter);
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/**
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* Compare two iterators for equivalence.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if EQUAL
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*/
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bool operator==(nsDequeIterator& aIter);
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/**
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* Compare two iterators for non strict decreasing order.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if this object points to the same element, or
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* an element after the element pointed to by aIter.
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* FALSE if this and aIter are not iterating over
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* the same deque.
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*/
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bool operator>=(nsDequeIterator& aIter);
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/**
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* Pre-increment operator
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* Iterator will advance one index towards the end.
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*
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* @return object_at(++index)
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*/
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void* operator++();
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/**
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* Post-increment operator
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* Iterator will advance one index towards the end.
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*
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* @param param is ignored
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* @return object_at(mIndex++)
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*/
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void* operator++(int);
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/**
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* Pre-decrement operator
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* Iterator will advance one index towards the beginning.
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*
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* @return object_at(--index)
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*/
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void* operator--();
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/**
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* Post-decrement operator
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* Iterator will advance one index towards the beginning.
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*
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* @param param is ignored
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* @return object_at(index--)
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*/
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void* operator--(int);
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/**
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* Retrieve the the iterator's notion of current node.
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*
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* Note that the iterator floats, so you don't need to do:
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* <code>++iter; aDeque.PopFront();</code>
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* Unless you actually want your iterator to jump 2 positions
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* relative to its origin.
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*
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* Picture: [1 2i 3 4]
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* PopFront()
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* Picture: [2 3i 4]
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* Note that I still happily points to object at the second index.
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*
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* @return object at i'th index
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*/
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void* GetCurrent();
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/**
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* Call this method when you want to iterate all the
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* members of the container, passing a functor along
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* to call your code.
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*
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* @param aFunctor object to call for each member
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* @return *this
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*/
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void ForEach(nsDequeFunctor& aFunctor) const;
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/**
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* Call this method when you want to iterate all the
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* members of the container, calling the functor you
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* passed with each member. This process will interrupt
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* if your function returns non 0 to this method.
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*
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* @param aFunctor object to call for each member
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* @return first nonzero result of aFunctor or 0.
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*/
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const void* FirstThat(nsDequeFunctor& aFunctor) const;
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protected:
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PRInt32 mIndex;
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const nsDeque& mDeque;
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};
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#endif
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