boost/geometry/srs/shared_grids_std.hpp

   1 // Boost.Geometry
   2
   3 // Copyright (c) 2018-2019, Oracle and/or its affiliates.
   4 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
   5
   6 // Use, modification and distribution is subject to the Boost Software License,
   7 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   8 // http://www.boost.org/LICENSE_1_0.txt)
   9
  10 #ifndef BOOST_GEOMETRY_SRS_SHARED_GRIDS_STD_HPP
  11 #define BOOST_GEOMETRY_SRS_SHARED_GRIDS_STD_HPP
  12
  13
  14 #include <boost/config.hpp>
  15
  16 #ifdef BOOST_NO_CXX14_HDR_SHARED_MUTEX
  17 #error "C++14 <shared_mutex> header required."
  18 #endif
  19
  20 #include <boost/geometry/srs/projections/grids.hpp>
  21
  22 #include <mutex>
  23 #include <shared_mutex>
  24
  25
  26 namespace boost { namespace geometry
  27 {
  28
  29 namespace srs
  30 {
  31
  32 class shared_grids_std
  33 {
  34
  35 // VS 2015 Update 2
  36 #if defined(_MSC_FULL_VER) && (_MSC_FULL_VER >= 190023918)
  37     typedef std::shared_mutex mutex_type;
  38 // Other C++17
  39 #elif !defined(BOOST_NO_CXX14_HDR_SHARED_MUTEX) && (__cplusplus > 201402L)
  40     typedef std::shared_mutex mutex_type;
  41 #else
  42     typedef std::shared_timed_mutex mutex_type;
  43 #endif
  44
  45 public:
  46     std::size_t size() const
  47     {
  48         std::shared_lock<mutex_type> lock(mutex);
  49         return gridinfo.size();
  50     }
  51
  52     bool empty() const
  53     {
  54         std::shared_lock<mutex_type> lock(mutex);
  55         return gridinfo.empty();
  56     }
  57
  58     typedef projections::detail::shared_grids_tag tag;
  59
  60     struct read_locked
  61     {
  62         read_locked(shared_grids_std & g)
  63             : gridinfo(g.gridinfo)
  64             , lock(g.mutex)
  65         {}
  66
  67         // should be const&
  68         projections::detail::pj_gridinfo & gridinfo;
  69
  70     private:
  71         std::shared_lock<mutex_type> lock;
  72     };
  73
  74     struct write_locked
  75     {
  76         write_locked(shared_grids_std & g)
  77             : gridinfo(g.gridinfo)
  78             , lock(g.mutex)
  79         {}
  80
  81         projections::detail::pj_gridinfo & gridinfo;
  82
  83     private:
  84         std::unique_lock<mutex_type> lock;
  85     };
  86
  87 private:
  88     projections::detail::pj_gridinfo gridinfo;
  89     mutable mutex_type mutex;
  90 };
  91
  92
  93 } // namespace srs
  94
  95
  96 }} // namespace boost::geometry
  97
  98
  99 #endif // BOOST_GEOMETRY_SRS_SHARED_GRIDS_STD_HPP