// -*- C++ -*-
// ---------------------------------------------------------------------------

#ifndef HEP_STACK_SRC
#define HEP_STACK_SRC

/*
 * Simplified stack class.
 * It is intended to be used as a replacement of the standard class where
 * full functionality of <stack> is not required, but it is essential
 * to have highly portable and effective code.
 *
 * This file should be used exclusively inside *.cc files.
 * Usage inside header files can result to a clash with standard <stack>.
 *
 * @author Evgeni Chernyaev  <Evgueni.Tcherniaev@cern.ch>
 */
template<class T>
class stack {
 private:
  int k, max_size;
  T * v;

 public:
  stack() :  k(0), max_size(20), v(new T[20]) {}
  ~stack() { delete [] v; }  

  int    size()    const { return k; }
  T      top ()    const { return v[k-1]; }
  T &    top ()          { return v[k-1]; }
  void   pop ()          { k--; }
  void   push(T a) {
    if (k == max_size) {
      T * w     = v;
      max_size *= 2;
      v         = new T[max_size];
      for (int i=0; i<k; i++) v[i] = w[i];
      delete [] w;
    }
    v[k++] = a;
  }
};

#endif /* HEP_STACK_SRC */