boost/boost/align/detail/aligned_alloc.hpp

/*
 (c) 2014 Glen Joseph Fernandes
 glenjofe at gmail dot com

 Distributed under the Boost Software
 License, Version 1.0.
 http://boost.org/LICENSE_1_0.txt
*/
#ifndef BOOST_ALIGN_DETAIL_ALIGNED_ALLOC_HPP
#define BOOST_ALIGN_DETAIL_ALIGNED_ALLOC_HPP

#include <boost/assert.hpp>
#include <boost/config.hpp>
#include <boost/align/align.hpp>
#include <boost/align/alignment_of.hpp>
#include <boost/align/detail/is_alignment.hpp>
#include <cstdlib>

namespace boost {
    namespace alignment {
        inline void* aligned_alloc(std::size_t alignment,
            std::size_t size) BOOST_NOEXCEPT
        {
            BOOST_ASSERT(detail::is_alignment(alignment));
            if (alignment < alignment_of<void*>::value) {
                alignment = alignment_of<void*>::value;
            }
            std::size_t n = size + alignment - 1;
            void* p1 = 0;
            void* p2 = std::malloc(n + sizeof p1);
            if (p2) {
                p1 = static_cast<char*>(p2) + sizeof p1;
                (void)align(alignment, size, p1, n);
                *(static_cast<void**>(p1) - 1) = p2;
            }
            return p1;
        }

        inline void aligned_free(void* ptr)
            BOOST_NOEXCEPT
        {
            if (ptr) {
                void* p = *(static_cast<void**>(ptr) - 1);
                std::free(p);
            }
        }
    }
}

#endif