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