stack.h

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#ifndef STACK_H
#define STACK_H

#include <itpp/base/itassert.h>


namespace itpp
{

template<class T>
class Stack
{
public:
  Stack();
  Stack(int n);
  Stack(const Stack<T> &s);
  virtual ~Stack();

  T pop();
  T peek() const;
  void push(T v);
  void clear();

  void operator=(const Stack<T> &s);

  int size() const { return ndata; }
  int no_elements() const { return valptr; }
  void set_size(int n, bool copy = false);

private:
  int valptr;
  int ndata;
  T *data;

private:
  void alloc(int n);
  void free();
};

// --------------------------- Implementation starts here ----------------------------------

template<class T>
Stack<T>::Stack()
{
  data = 0;
  ndata = 0;
  valptr = 0;
}

template<class T>
Stack<T>::Stack(int n)
{
  alloc(n);
  valptr = 0;
}

template<class T>
Stack<T>::Stack(const Stack<T> &s)
{
  data = NULL;
  ndata = 0;
  valptr = s.valptr;
  alloc(s.ndata);
  for (int i = 0; i < s.ndata; i++)
    data[i] = s.data[i];
}

template<class T>
Stack<T>::~Stack()
{
  free();
}

template <class T>
T Stack<T>::pop()
{
  it_error_if(valptr == 0, "Stack<T>::pop: Empty stack");
  valptr--;
  return data[valptr];
}

template <class T>
T Stack<T>::peek() const
{
  it_error_if(valptr == 0, "Stack<T>::peek: Empty stack");
  return data[valptr-1];
}

template <class T>
void Stack<T>::push(T v)
{
  it_error_if(valptr >= ndata, "Stack<T>::push: Full stack");
  data[valptr] = v;
  valptr++;
}

template <class T>
void Stack<T>::clear()
{
  valptr = 0;
}

template<class T>
void Stack<T>::alloc(int n)
{
  if (n == 0) {
    data = NULL;
    ndata = 0;
  }
  else {
    data = new T[n];
    it_assert_debug(data != 0, "Out of memory in Stack::alloc");
  }
  ndata = n;
}

template<class T>
void Stack<T>::free()
{

  delete [] data;

  data = 0;
  ndata = 0;
}

template<class T>
void Stack<T>::operator=(const Stack<T> &s)
{
  set_size(s.ndata);
  for (int i = 0; i < ndata; i++)
    data[i] = s.data[i];
  valptr = 0;
}

template<class T>
void Stack<T>::set_size(int sz, bool copy)
{
  int i, min;
  T *tmp;

  if (ndata == sz)
    return;

  if (copy) {
    tmp = data;
    min = ndata < sz ? ndata : sz;
    alloc(sz);
    for (i = 0; i < min; i++)
      data[i] = tmp[i];
    delete [] tmp;
  }
  else {
    free();
    alloc(sz);
  }
  ndata = sz;
}

} // namespace itpp

#endif // #ifndef STACK_H