Qucs-core  0.0.19
sample3-inl.h
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00001 // Copyright 2005, Google Inc.
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00017 //
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00029 
00030 // A sample program demonstrating using Google C++ testing framework.
00031 //
00032 // Author: wan@google.com (Zhanyong Wan)
00033 
00034 #ifndef GTEST_SAMPLES_SAMPLE3_INL_H_
00035 #define GTEST_SAMPLES_SAMPLE3_INL_H_
00036 
00037 #include <stddef.h>
00038 
00039 
00040 // Queue is a simple queue implemented as a singled-linked list.
00041 //
00042 // The element type must support copy constructor.
00043 template <typename E>  // E is the element type
00044 class Queue;
00045 
00046 // QueueNode is a node in a Queue, which consists of an element of
00047 // type E and a pointer to the next node.
00048 template <typename E>  // E is the element type
00049 class QueueNode {
00050   friend class Queue<E>;
00051 
00052  public:
00053   // Gets the element in this node.
00054   const E& element() const { return element_; }
00055 
00056   // Gets the next node in the queue.
00057   QueueNode* next() { return next_; }
00058   const QueueNode* next() const { return next_; }
00059 
00060  private:
00061   // Creates a node with a given element value.  The next pointer is
00062   // set to NULL.
00063   explicit QueueNode(const E& an_element) : element_(an_element), next_(NULL) {}
00064 
00065   // We disable the default assignment operator and copy c'tor.
00066   const QueueNode& operator = (const QueueNode&);
00067   QueueNode(const QueueNode&);
00068 
00069   E element_;
00070   QueueNode* next_;
00071 };
00072 
00073 template <typename E>  // E is the element type.
00074 class Queue {
00075  public:
00076   // Creates an empty queue.
00077   Queue() : head_(NULL), last_(NULL), size_(0) {}
00078 
00079   // D'tor.  Clears the queue.
00080   ~Queue() { Clear(); }
00081 
00082   // Clears the queue.
00083   void Clear() {
00084     if (size_ > 0) {
00085       // 1. Deletes every node.
00086       QueueNode<E>* node = head_;
00087       QueueNode<E>* next = node->next();
00088       for (; ;) {
00089         delete node;
00090         node = next;
00091         if (node == NULL) break;
00092         next = node->next();
00093       }
00094 
00095       // 2. Resets the member variables.
00096       head_ = last_ = NULL;
00097       size_ = 0;
00098     }
00099   }
00100 
00101   // Gets the number of elements.
00102   size_t Size() const { return size_; }
00103 
00104   // Gets the first element of the queue, or NULL if the queue is empty.
00105   QueueNode<E>* Head() { return head_; }
00106   const QueueNode<E>* Head() const { return head_; }
00107 
00108   // Gets the last element of the queue, or NULL if the queue is empty.
00109   QueueNode<E>* Last() { return last_; }
00110   const QueueNode<E>* Last() const { return last_; }
00111 
00112   // Adds an element to the end of the queue.  A copy of the element is
00113   // created using the copy constructor, and then stored in the queue.
00114   // Changes made to the element in the queue doesn't affect the source
00115   // object, and vice versa.
00116   void Enqueue(const E& element) {
00117     QueueNode<E>* new_node = new QueueNode<E>(element);
00118 
00119     if (size_ == 0) {
00120       head_ = last_ = new_node;
00121       size_ = 1;
00122     } else {
00123       last_->next_ = new_node;
00124       last_ = new_node;
00125       size_++;
00126     }
00127   }
00128 
00129   // Removes the head of the queue and returns it.  Returns NULL if
00130   // the queue is empty.
00131   E* Dequeue() {
00132     if (size_ == 0) {
00133       return NULL;
00134     }
00135 
00136     const QueueNode<E>* const old_head = head_;
00137     head_ = head_->next_;
00138     size_--;
00139     if (size_ == 0) {
00140       last_ = NULL;
00141     }
00142 
00143     E* element = new E(old_head->element());
00144     delete old_head;
00145 
00146     return element;
00147   }
00148 
00149   // Applies a function/functor on each element of the queue, and
00150   // returns the result in a new queue.  The original queue is not
00151   // affected.
00152   template <typename F>
00153   Queue* Map(F function) const {
00154     Queue* new_queue = new Queue();
00155     for (const QueueNode<E>* node = head_; node != NULL; node = node->next_) {
00156       new_queue->Enqueue(function(node->element()));
00157     }
00158 
00159     return new_queue;
00160   }
00161 
00162  private:
00163   QueueNode<E>* head_;  // The first node of the queue.
00164   QueueNode<E>* last_;  // The last node of the queue.
00165   size_t size_;  // The number of elements in the queue.
00166 
00167   // We disallow copying a queue.
00168   Queue(const Queue&);
00169   const Queue& operator = (const Queue&);
00170 };
00171 
00172 #endif  // GTEST_SAMPLES_SAMPLE3_INL_H_