pointer_const_array_impl.hpp

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/*
 * Copyright (c) 2012-2015:  G-CSC, Goethe University Frankfurt
 * Author: Sebastian Reiter
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 */
 
#ifndef __H__UG__pointer_array_impl__
#define __H__UG__pointer_array_impl__
 
#include <cstring>
#include <algorithm>
 
namespace ug
{
 
template <class TPtr>
PointerConstArray<TPtr>::
PointerConstArray() :
  m_array(NULL), m_data(NULL), m_size(0), m_capacity(0)
{
}
 
template <class TPtr>
PointerConstArray<TPtr>::
PointerConstArray(const PointerConstArray& pa)
{
  assign_pointer_const_array(pa);
}
 
template <class TPtr>
PointerConstArray<TPtr>::
~PointerConstArray()
{
//  only free local memory...
  if(m_data)
    delete[] m_data;
}
 
template <class TPtr>
PointerConstArray<TPtr>& PointerConstArray<TPtr>::
operator=(const PointerConstArray& pa)
{
//  free memory if necessary
  if(m_data)
    delete[] m_data;
 
//  assign the new class
  assign_pointer_const_array(pa);
 
//  return reference to this
  return *this;
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
assign_pointer_const_array(const PointerConstArray& pa)
{
  m_size = pa.m_size;
//  check whether pa points to an external array or not
  if(pa.m_array != pa.m_data){
  //  we'll point to the same external array
    m_array = pa.m_array;
    m_data = NULL;
    m_capacity = 0;
  }
  else{
  //  we'll create our own array and copy the contents
    if(m_size){
      m_data = new TPtr[m_size];
      memcpy(m_data, pa.m_data, sizeof(TPtr) * m_size);
    }else
      m_data = NULL;
    m_capacity = m_size;
    m_array = m_data;
  }
}
 
template <class TPtr>
inline size_t PointerConstArray<TPtr>::
size() const
{
  return m_size;
}
 
template <class TPtr>
inline bool PointerConstArray<TPtr>::
empty() const
{
  return m_size == 0;
}
 
template <class TPtr>
inline TPtr const PointerConstArray<TPtr>::
operator[](size_t i) const
{
  UG_ASSERT(i < m_size, "bad index!");
  return m_array[i];
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
set_external_array(TPtr const *array, size_t size, bool bCopy)
{
  if(bCopy){
  //don't call resize!
    if(size > m_capacity){
      delete[] m_data;
      m_data = new TPtr[size];
      m_capacity = size;
    }
 
    if(size > 0)
      memcpy(m_data, array, sizeof(TPtr) * size);
 
    m_array = m_data;
    m_size = size;
  }
  else{
    m_array = array;
    m_size = size;
  }
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
reserve(size_t capacity)
{
//  only copy old data, if we're actually using it
  reserve(capacity, m_array == m_data);
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
reserve(size_t capacity, bool copyOldData)
{
  if(capacity > m_capacity){
    PtrArray newData = new TPtr[capacity];
 
    if(m_data && copyOldData)
      memcpy(newData, m_data, sizeof(TPtr) * m_capacity);
 
    m_capacity = capacity;
 
  //  update pointers to new memory location and free old data.
  //  if m_array still points to an external array, we won't update the pointer.
    if(m_array == m_data)
      m_array = newData;
 
    delete[] m_data;
    m_data = newData;
  }
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
clear()
{
  m_size = 0;
}
 
template <class TPtr>
void PointerConstArray<TPtr>::
push_back(TPtr p)
{
  using namespace std;
//  first make sure, that m_array is contained in m_data
  if(m_array != m_data){
  //  since we push something back, we double the capacity now
    reserve(max<size_t>(1, m_size * 2), false);
    if(m_size > 0)
      memcpy(m_data, m_array, sizeof(TPtr) * m_size);
    m_array = m_data;
  }
 
//  now check whether there's space left in m_data
  if(m_size >= m_capacity)
    reserve(max<size_t>(1, m_capacity * 2), true);
 
//  assign the new entry
  m_data[m_size] = p;
  ++m_size;
}
 
}// end of namespace
 
#endif