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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef txStack_h___
#define txStack_h___
#include "nsTArray.h"
class txStack : private nsTArray<void*>
{
public:
/**
* Returns the specified object from the top of this stack,
* without removing it from the stack.
*
* @return a pointer to the object that is the top of this stack.
*/
inline void* peek()
{
NS_ASSERTION(!isEmpty(), "peeking at empty stack");
return !isEmpty() ? ElementAt(Length() - 1) : nullptr;
}
/**
* Adds the specified object to the top of this stack.
*
* @param obj a pointer to the object that is to be added to the
* top of this stack.
*/
inline nsresult push(void* aObject)
{
return AppendElement(aObject) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}
/**
* Removes and returns the specified object from the top of this
* stack.
*
* @return a pointer to the object that was the top of this stack.
*/
inline void* pop()
{
void* object = nullptr;
NS_ASSERTION(!isEmpty(), "popping from empty stack");
if (!isEmpty())
{
const uint32_t count = Length() - 1;
object = ElementAt(count);
RemoveElementAt(count);
}
return object;
}
/**
* Returns true if there are no objects in the stack.
*
* @return true if there are no objects in the stack.
*/
inline bool isEmpty()
{
return IsEmpty();
}
/**
* Returns the number of elements in the Stack.
*
* @return the number of elements in the Stack.
*/
inline int32_t size()
{
return Length();
}
private:
friend class txStackIterator;
};
class txStackIterator
{
public:
/**
* Creates an iterator for the given stack.
*
* @param aStack the stack to create an iterator for.
*/
inline
explicit txStackIterator(txStack* aStack) : mStack(aStack),
mPosition(0)
{
}
/**
* Returns true if there is more objects on the stack.
*
* @return .
*/
inline bool hasNext()
{
return (mPosition < mStack->Length());
}
/**
* Returns the next object pointer from the stack.
*
* @return .
*/
inline void* next()
{
if (mPosition == mStack->Length()) {
return nullptr;
}
return mStack->ElementAt(mPosition++);
}
private:
txStack* mStack;
uint32_t mPosition;
};
#endif /* txStack_h___ */
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