ceph/src/boost/boost/vmd/tuple/pop_back.hpp

   1
   2 //  (C) Copyright Edward Diener 2015
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6
   7 #if !defined(BOOST_VMD_TUPLE_POP_BACK_HPP)
   8 #define BOOST_VMD_TUPLE_POP_BACK_HPP
   9
  10 #include <boost/vmd/detail/setup.hpp>
  11
  12 #if BOOST_PP_VARIADICS
  13
  14 #include <boost/preprocessor/comparison/equal.hpp>
  15 #include <boost/preprocessor/control/iif.hpp>
  16 #include <boost/preprocessor/tuple/pop_back.hpp>
  17 #include <boost/preprocessor/tuple/size.hpp>
  18 #include <boost/vmd/empty.hpp>
  19
  20 /*
  21
  22   The succeeding comments in this file are in doxygen format.
  23
  24 */
  25
  26 /** \file
  27 */
  28
  29 /** \def BOOST_VMD_TUPLE_POP_BACK(tuple)
  30
  31     \brief pops an element from the end of a tuple.
  32
  33     tuple = tuple to pop an element from.
  34
  35     If the tuple is an empty tuple the result is undefined.
  36     If the tuple is a single element the result is an empty tuple.
  37     Otherwise the result is a tuple after removing the last element.
  38 */
  39
  40 #define BOOST_VMD_TUPLE_POP_BACK(tuple) \
  41     BOOST_PP_IIF \
  42         ( \
  43         BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1), \
  44         BOOST_VMD_EMPTY, \
  45         BOOST_PP_TUPLE_POP_BACK \
  46         ) \
  47     (tuple) \
  48 /**/
  49
  50 /** \def BOOST_VMD_TUPLE_POP_BACK_Z(z,tuple)
  51
  52     \brief pops an element from the end of a tuple. It reenters BOOST_PP_REPEAT with maximum efficiency.
  53
  54     z     = the next available BOOST_PP_REPEAT dimension.
  55     tuple = tuple to pop an element from.
  56
  57     If the tuple is an empty tuple the result is undefined.
  58     If the tuple is a single element the result is an empty tuple.
  59     Otherwise the result is a tuple after removing the last element.
  60 */
  61
  62 #define BOOST_VMD_TUPLE_POP_BACK_Z(z,tuple) \
  63     BOOST_PP_IIF \
  64         ( \
  65         BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1), \
  66         BOOST_VMD_EMPTY, \
  67         BOOST_PP_TUPLE_POP_BACK_Z \
  68         ) \
  69     (z,tuple) \
  70 /**/
  71
  72 #endif /* BOOST_PP_VARIADICS */
  73 #endif /* BOOST_VMD_TUPLE_POP_BACK_HPP */