libcruft-util/alloc/raw/affix.hpp

/*
 * 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 Danny Robson <danny@nerdcruft.net>
 */

#ifndef CRUFT_UTIL_ALLOC_RAW_AFFIX_HPP
#define CRUFT_UTIL_ALLOC_RAW_AFFIX_HPP

#include "../../view.hpp"

#include <cstddef>

namespace util::alloc::raw {
    /// a raw memory allocator which initialises an instance of PrefixT
    /// immediately before each allocation and, if specified, an instance
    /// of SuffixT after the allocation.
    ///
    /// uses an instance of ParentT to actually perform the bulk allocations.
    ///
    /// useful for sentinels, reference counts, etc.
    template <class ParentT, class PrefixT, class SuffixT>
    class affix {
        util::view<std::byte*> allocate (size_t bytes);
        util::view<std::byte*> allocate (size_t bytes, size_t align);

        void deallocate (util::view<std::byte*> ptr) { return deallocate (ptr.data (), ptr.size ()); }
        void deallocate (util::view<std::byte*> ptr, size_t alignment) { return deallocate (ptr.data (), ptr.size (), alignment); }
        void deallocate (void *ptr, size_t bytes);
        void deallocate (void *ptr, size_t bytes, size_t align);

        std::byte* begin (void);
        const std::byte* begin (void) const;

        std::byte* end (void);
        const std::byte* end (void) const;

        size_t offset (const void*) const;
    };
}

#endif