getfem_copyable_ptr.h

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/* -*- c++ -*- (enables emacs c++ mode) */
/*===========================================================================
 
 Copyright (C) 2012-2020 Andriy Andreykiv
 
 This file is a part of GetFEM
 
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 (at your option) any later version along with the GCC Runtime Library
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 License and GCC Runtime Library Exception for more details.
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/**@file getfem_copyable_ptr.h
@author  Andriy Andreykiv <andriy.andreykiv@gmail.com>
@date October 6th, 2015.
@brief A smart pointer that copies the value it points to on copy operations
*/
#pragma once
 
#include <memory>
#include <cstddef>
 
namespace getfem {
 
/**
  A wrapper around a unique_ptr that clones the value on copy
*/
template<class T> class copyable_ptr{
  std::unique_ptr<T> p_ = std::unique_ptr<T>(nullptr);
public:
  copyable_ptr() = default;
 
  copyable_ptr(std::unique_ptr<T> p) : p_(std::move(p)) {}
 
  copyable_ptr(const copyable_ptr<T> &x)
    : p_(x.p_ ? std::make_unique<T>(*x.p_) : nullptr)  {}
 
  copyable_ptr(copyable_ptr<T> &&x) : p_(std::move(*x.p_))  {}
 
  copyable_ptr<T> &operator=(const copyable_ptr<T> &x){
    if (x.p_) p_ = std::make_unique<T>(*x.p_);
    return *this;
  }
 
  copyable_ptr<T> &operator=(copyable_ptr<T> &&x){
    p_ = std::move(x.p_);
    return *this;
  }
 
  operator bool() const {return p_.operator bool();}
 
  T& operator*() const {return p_.operator*();}
 
  T* operator->() const {return p_.operator->();}
};
 
} // namespace getfem