libcruft-util/io_posix.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 2010-2016 Danny Robson <danny@nerdcruft.net>
 */

#ifndef __UTIL_IO_POSIX_HPP
#define __UTIL_IO_POSIX_HPP

#include "posix/fd.hpp"

#include "view.hpp"

#include <type_traits>
#include <experimental/filesystem>

#include <sys/mman.h>
#include <fcntl.h>

namespace util {
    namespace detail { namespace posix {
        class mapped_file {
        public:
            mapped_file (const std::experimental::filesystem::path&, int fflags = O_RDONLY | O_BINARY, int mflags = PROT_READ);
            mapped_file (const util::posix::fd&,  int mflags = PROT_READ);

            mapped_file (const mapped_file&) = delete;
            mapped_file& operator= (const mapped_file&) = delete;

            ~mapped_file ();

            bool empty (void) const;

            /// returns the total allocated mapped region in bytes.
            ///
            /// result is typed size_t (rather than a signed type) because we
            /// often use this in conjunction with sizeof and packed structure.
            /// it is greatly simpler to cast to signed where it's actually
            /// required rather than the other way around.
            size_t size (void) const;

            const uint8_t* data (void) const &;
            uint8_t*       data (void) &;

            uint8_t* begin (void) &;
            uint8_t* end   (void) &;

            const uint8_t* begin (void) const &;
            const uint8_t* end   (void) const &;

            const uint8_t* cbegin (void) const &;
            const uint8_t* cend   (void) const &;

            template <typename T>
            util::view<std::add_const_t<T>*>
            as_view () const &;

            template <typename T>
            util::view<T*>
            as_view () &;

        private:
            uint8_t *m_data;
            size_t   m_size;
        };
    } }

    typedef detail::posix::mapped_file mapped_file;
}

#include "io_posix.ipp"

#endif