ceph/src/boost/libs/vmd/include/boost/vmd/is_empty_array.hpp

   1
   2 //  (C) Copyright Edward Diener 2011-2015
   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_IS_EMPTY_ARRAY_HPP)
   8 #define BOOST_VMD_IS_EMPTY_ARRAY_HPP
   9
  10 #include <boost/vmd/detail/setup.hpp>
  11
  12 #if BOOST_PP_VARIADICS
  13
  14 #include <boost/preprocessor/control/iif.hpp>
  15 #include <boost/vmd/is_array.hpp>
  16 #include <boost/vmd/identity.hpp>
  17 #include <boost/vmd/detail/is_empty_array.hpp>
  18
  19 /*
  20
  21   The succeeding comments in this file are in doxygen format.
  22
  23 */
  24
  25 /** \file
  26 */
  27
  28 /** \def BOOST_VMD_IS_EMPTY_ARRAY(sequence)
  29
  30     \brief Tests whether a sequence is an empty Boost PP array.
  31
  32     An empty Boost PP array is a two element tuple where the first
  33     size element is 0 and the second element is a tuple with a single
  34     empty element, ie. '(0,())'.
  35
  36     sequence = a possible empty array
  37
  38     returns = 1 if the sequence is an empty Boost PP array
  39               0 if it is not.
  40
  41     The macro will generate a preprocessing error if the sequence
  42     is in the form of an array but its first tuple element, instead
  43     of being a number, is a preprocessor token which VMD cannot parse,
  44     as in the example '(&0,())' which is a valid tuple but an invalid
  45     array.
  46
  47 */
  48
  49 #define BOOST_VMD_IS_EMPTY_ARRAY(sequence) \
  50     BOOST_VMD_IDENTITY_RESULT \
  51         ( \
  52         BOOST_PP_IIF \
  53             ( \
  54             BOOST_VMD_IS_ARRAY(sequence), \
  55             BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \
  56             BOOST_VMD_IDENTITY(0) \
  57             ) \
  58         (sequence) \
  59         ) \
  60 /**/
  61
  62 /** \def BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence)
  63
  64     \brief Tests whether a sequence is an empty Boost PP array. Re-entrant version.
  65
  66     An empty Boost PP array is a two element tuple where the first
  67     size element is 0 and the second element is a tuple with a single
  68     empty element, ie. '(0,())'.
  69
  70     d        = The next available BOOST_PP_WHILE iteration.
  71     sequence = a possible empty array
  72
  73     returns = 1 if the sequence is an empty Boost PP array
  74               0 if it is not.
  75
  76     The macro will generate a preprocessing error if the sequence
  77     is in the form of an array but its first tuple element, instead
  78     of being a number, is a preprocessor token which VMD cannot parse,
  79     as in the example '(&0,())' which is a valid tuple but an invalid
  80     array.
  81
  82 */
  83
  84 #define BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence) \
  85     BOOST_VMD_IDENTITY_RESULT \
  86         ( \
  87         BOOST_PP_IIF \
  88             ( \
  89             BOOST_VMD_IS_ARRAY_D(d,sequence), \
  90             BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \
  91             BOOST_VMD_IDENTITY(0) \
  92             ) \
  93         (sequence) \
  94         ) \
  95 /**/
  96
  97 #endif /* BOOST_PP_VARIADICS */
  98 #endif /* BOOST_VMD_IS_EMPTY_ARRAY_HPP */