block_allocator.h

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// Author(s): Maurice Laveaux
// Copyright: see the accompanying file COPYING or copy at
// https://github.com/mCRL2org/mCRL2/blob/master/COPYING
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
 
#ifndef MCRL2_UTILITIES_BLOCK_ALLOCATOR_H_
#define MCRL2_UTILITIES_BLOCK_ALLOCATOR_H_
 
#include "memory_pool.h"
 
#include <memory>
#include <stddef.h>
 
namespace mcrl2
{
namespace utilities
{
 
template <class T,
          std::size_t ElementsPerBlock = 1024,
          bool ThreadSafe = false>
class block_allocator : public memory_pool<T, ElementsPerBlock, ThreadSafe>
{
private:
  using super = memory_pool<T, ElementsPerBlock, ThreadSafe>;
 
public:
  using value_type = T;
  using size_type = std::size_t;
  using difference_type = std::ptrdiff_t;
 
  template <class U>
  struct rebind
  {
      typedef block_allocator<U, ElementsPerBlock, ThreadSafe> other;
  };
 
  block_allocator() = default;
 
  T* allocate(size_type n, const void* hint = nullptr)
  {
    if (n != 1 || hint)
    {
      throw std::bad_alloc();
    }
 
    return super::allocate();
  }
 
  void deallocate(T* p, size_type)
  {
    super::deallocate(p);
  }
 
  // Move assignment and construction is possible.
  block_allocator(block_allocator&&) = default;
  block_allocator& operator=(block_allocator&&) = default;
};
 
} // namespace utilities
} // namespace mcrl2
 
#endif