yaml-cpp

sample3-inl.h (5360B)

---

 // Copyright 2005, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // A sample program demonstrating using Google C++ testing framework.
 
 #ifndef GTEST_SAMPLES_SAMPLE3_INL_H_
 #define GTEST_SAMPLES_SAMPLE3_INL_H_
 
 #include <stddef.h>
 
 
 // Queue is a simple queue implemented as a singled-linked list.
 //
 // The element type must support copy constructor.
 template <typename E>  // E is the element type
 class Queue;
 
 // QueueNode is a node in a Queue, which consists of an element of
 // type E and a pointer to the next node.
 template <typename E>  // E is the element type
 class QueueNode {
   friend class Queue<E>;
 
  public:
   // Gets the element in this node.
   const E& element() const { return element_; }
 
   // Gets the next node in the queue.
   QueueNode* next() { return next_; }
   const QueueNode* next() const { return next_; }
 
  private:
   // Creates a node with a given element value.  The next pointer is
   // set to NULL.
   explicit QueueNode(const E& an_element)
       : element_(an_element), next_(nullptr) {}
 
   // We disable the default assignment operator and copy c'tor.
   const QueueNode& operator = (const QueueNode&);
   QueueNode(const QueueNode&);
 
   E element_;
   QueueNode* next_;
 };
 
 template <typename E>  // E is the element type.
 class Queue {
  public:
   // Creates an empty queue.
   Queue() : head_(nullptr), last_(nullptr), size_(0) {}
 
   // D'tor.  Clears the queue.
   ~Queue() { Clear(); }
 
   // Clears the queue.
   void Clear() {
     if (size_ > 0) {
       // 1. Deletes every node.
       QueueNode<E>* node = head_;
       QueueNode<E>* next = node->next();
       for (; ;) {
         delete node;
         node = next;
         if (node == nullptr) break;
         next = node->next();
       }
 
       // 2. Resets the member variables.
       head_ = last_ = nullptr;
       size_ = 0;
     }
   }
 
   // Gets the number of elements.
   size_t Size() const { return size_; }
 
   // Gets the first element of the queue, or NULL if the queue is empty.
   QueueNode<E>* Head() { return head_; }
   const QueueNode<E>* Head() const { return head_; }
 
   // Gets the last element of the queue, or NULL if the queue is empty.
   QueueNode<E>* Last() { return last_; }
   const QueueNode<E>* Last() const { return last_; }
 
   // Adds an element to the end of the queue.  A copy of the element is
   // created using the copy constructor, and then stored in the queue.
   // Changes made to the element in the queue doesn't affect the source
   // object, and vice versa.
   void Enqueue(const E& element) {
     QueueNode<E>* new_node = new QueueNode<E>(element);
 
     if (size_ == 0) {
       head_ = last_ = new_node;
       size_ = 1;
     } else {
       last_->next_ = new_node;
       last_ = new_node;
       size_++;
     }
   }
 
   // Removes the head of the queue and returns it.  Returns NULL if
   // the queue is empty.
   E* Dequeue() {
     if (size_ == 0) {
       return nullptr;
     }
 
     const QueueNode<E>* const old_head = head_;
     head_ = head_->next_;
     size_--;
     if (size_ == 0) {
       last_ = nullptr;
     }
 
     E* element = new E(old_head->element());
     delete old_head;
 
     return element;
   }
 
   // Applies a function/functor on each element of the queue, and
   // returns the result in a new queue.  The original queue is not
   // affected.
   template <typename F>
   Queue* Map(F function) const {
     Queue* new_queue = new Queue();
     for (const QueueNode<E>* node = head_; node != nullptr;
          node = node->next_) {
       new_queue->Enqueue(function(node->element()));
     }
 
     return new_queue;
   }
 
  private:
   QueueNode<E>* head_;  // The first node of the queue.
   QueueNode<E>* last_;  // The last node of the queue.
   size_t size_;  // The number of elements in the queue.
 
   // We disallow copying a queue.
   Queue(const Queue&);
   const Queue& operator = (const Queue&);
 };
 
 #endif  // GTEST_SAMPLES_SAMPLE3_INL_H_