123 lines
2.8 KiB
C++
123 lines
2.8 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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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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#ifndef txStack_h___
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#define txStack_h___
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#include "nsTArray.h"
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class txStack : private nsTArray<void*>
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{
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public:
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/**
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* Returns the specified object from the top of this stack,
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* without removing it from the stack.
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*
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* @return a pointer to the object that is the top of this stack.
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*/
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inline void* peek()
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{
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NS_ASSERTION(!isEmpty(), "peeking at empty stack");
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return !isEmpty() ? ElementAt(Length() - 1) : nullptr;
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}
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/**
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* Adds the specified object to the top of this stack.
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*
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* @param obj a pointer to the object that is to be added to the
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* top of this stack.
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*/
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inline nsresult push(void* aObject)
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{
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return AppendElement(aObject) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
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}
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/**
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* Removes and returns the specified object from the top of this
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* stack.
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*
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* @return a pointer to the object that was the top of this stack.
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*/
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inline void* pop()
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{
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void* object = nullptr;
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NS_ASSERTION(!isEmpty(), "popping from empty stack");
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if (!isEmpty())
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{
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const uint32_t count = Length() - 1;
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object = ElementAt(count);
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RemoveElementAt(count);
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}
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return object;
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}
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/**
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* Returns true if there are no objects in the stack.
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*
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* @return true if there are no objects in the stack.
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*/
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inline bool isEmpty()
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{
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return IsEmpty();
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}
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/**
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* Returns the number of elements in the Stack.
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*
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* @return the number of elements in the Stack.
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*/
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inline int32_t size()
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{
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return Length();
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}
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private:
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friend class txStackIterator;
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};
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class txStackIterator
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{
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public:
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/**
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* Creates an iterator for the given stack.
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*
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* @param aStack the stack to create an iterator for.
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*/
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inline
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explicit txStackIterator(txStack* aStack) : mStack(aStack),
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mPosition(0)
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{
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}
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/**
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* Returns true if there is more objects on the stack.
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*
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* @return .
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*/
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inline bool hasNext()
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{
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return (mPosition < mStack->Length());
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}
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/**
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* Returns the next object pointer from the stack.
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*
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* @return .
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*/
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inline void* next()
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{
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if (mPosition == mStack->Length()) {
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return nullptr;
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}
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return mStack->ElementAt(mPosition++);
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}
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private:
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txStack* mStack;
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uint32_t mPosition;
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};
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#endif /* txStack_h___ */
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