libcruft-util/alloc/allocator.hpp

75 lines
2.0 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
*/
#pragma once
#include "../view.hpp"
#include <cstddef>
#include <utility>
// C++11 allocator concept conformant(ish) allocator adaptor, going from our
// allocator interface to that of the STL and friends.
namespace util::alloc {
template <typename ValueT, typename BackingT>
class allocator {
public:
typedef ValueT value_type;
template <typename ...Args>
explicit allocator (Args&& ...args):
m_backing (std::forward<Args> (args)...)
{ ; }
util::view<ValueT*>
allocate (size_t count)
{
return {
reinterpret_cast<ValueT*> (
m_backing.template allocate (
sizeof (ValueT) * count,
alignof (ValueT)
)
),
count
};
}
void
deallocate (ValueT *t, size_t count)
{
return m_backing.template deallocate (t, sizeof (ValueT) * count);
}
private:
BackingT &m_backing;
};
///////////////////////////////////////////////////////////////////////////
// convenience type-inferring constructor for allocators.
template <typename ValueT, typename BackingT>
auto
make_allocator (BackingT &backing)
{
return allocator<ValueT,BackingT> (backing);
}
}