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//
// immer: immutable data structures for C++
// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
//
// This software is distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
//
#pragma once
#include <cstdio>
namespace immer {
/*!
* Appends a default constructed extra object of type `T` at the
* *before* the requested region.
*
* @tparam T Type of the appended data.
* @tparam Base Type of the parent heap.
*/
template <typename T, typename Base>
struct with_data : Base
{
using base_t = Base;
template <typename... Tags>
static void* allocate(std::size_t size, Tags... tags)
{
auto p = base_t::allocate(size + sizeof(T), tags...);
return new (p) T{} + 1;
}
template <typename... Tags>
static void deallocate(std::size_t size, void* p, Tags... tags)
{
auto dp = static_cast<T*>(p) - 1;
dp->~T();
base_t::deallocate(size + sizeof(T), dp, tags...);
}
};
} // namespace immer
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