nobloat.h

来自「很经典的书籍」· C头文件 代码 · 共 94 行

//: C05:Nobloat.h
// Shares code for storing pointers in a Stack
#ifndef NOBLOAT_H
#define NOBLOAT_H
#include <cassert>
#include <cstddef>
#include <cstring>

// The primary template
template<class T>
class Stack {
  T* data;
  std::size_t count;
  std::size_t capacity;
  enum {INIT = 5};
public:
  Stack() {
    count = 0;
    capacity = INIT;
    data = new T[INIT];
  }
  void push(const T& t) {
    if (count == capacity) {
      // Grow array store
      std::size_t newCapacity = 2*capacity;
      T* newData = new T[newCapacity];
      for (size_t i = 0; i < count; ++i)
        newData[i] = data[i];
      delete [] data;
      data = newData;
      capacity = newCapacity;
    }
    assert(count < capacity);
    data[count++] = t;
  }
  void pop() {
    assert(count > 0);
    --count;
  }
  T top() const {
    assert(count > 0);
    return data[count-1];
  }
  size_t size() const {return count;}
};

// Full specialization for void*
template<>
class Stack<void *> {
  void** data;
  std::size_t count;
  std::size_t capacity;
  enum {INIT = 5};
public:
  Stack() {
    count = 0;
    capacity = INIT;
    data = new void*[INIT];
  }
  void push(void* const & t) {
    if (count == capacity) {
      std::size_t newCapacity = 2*capacity;
      void** newData = new void*[newCapacity];
      std::memcpy(newData, data, count*sizeof(void*));
      delete [] data;
      data = newData;
      capacity = newCapacity;
    }
    assert(count < capacity);
    data[count++] = t;
  }
  void pop() {
    assert(count > 0);
    --count;
  }
  void* top() const {
    assert(count > 0);
    return data[count-1];
  }
  std::size_t size() const {return count;}
};

// Partial specialization for other pointer types
template<class T>
class Stack<T*> : private Stack<void *> {
  typedef Stack<void *> Base;
public:
  void push(T* const & t) {Base::push(t);}
  void pop() {Base::pop();}
  T* top() const {return static_cast<T*>(Base::top());}
  std::size_t size() {return Base::size();}
};
#endif // NOBLOAT_H ///:~