1/*=============================================================================
2 Copyright (c) 2001-2011 Joel de Guzman
3
4 Distributed under the Boost Software License, Version 1.0. (See accompanying
5 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6==============================================================================*/
7#if !defined(FUSION_ERASE_07232005_0534)
8#define FUSION_ERASE_07232005_0534
9
10#include <boost/fusion/support/config.hpp>
11#include <boost/fusion/iterator/equal_to.hpp>
12#include <boost/fusion/iterator/mpl/convert_iterator.hpp>
13#include <boost/fusion/view/joint_view/joint_view.hpp>
14#include <boost/fusion/view/iterator_range/iterator_range.hpp>
15#include <boost/fusion/support/detail/as_fusion_element.hpp>
16#include <boost/fusion/sequence/intrinsic/begin.hpp>
17#include <boost/fusion/sequence/intrinsic/end.hpp>
18#include <boost/fusion/adapted/mpl/mpl_iterator.hpp>
19#include <boost/fusion/support/is_sequence.hpp>
20#include <boost/utility/enable_if.hpp>
21#include <boost/mpl/if.hpp>
22
23namespace boost { namespace fusion
24{
25 namespace result_of
26 {
27 template <typename Sequence, typename First>
28 struct compute_erase_last // put this in detail!!!
29 {
30 typedef typename result_of::end<Sequence>::type seq_last_type;
31 typedef typename convert_iterator<First>::type first_type;
32 typedef typename
33 mpl::if_<
34 result_of::equal_to<first_type, seq_last_type>
35 , first_type
36 , typename result_of::next<first_type>::type
37 >::type
38 type;
39
40 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
41 static type
42 call(First const& first, mpl::false_)
43 {
44 return fusion::next(convert_iterator<First>::call(first));
45 }
46
47 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
48 static type
49 call(First const& first, mpl::true_)
50 {
51 return convert_iterator<First>::call(first);
52 }
53
54 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
55 static type
56 call(First const& first)
57 {
58 return call(first, result_of::equal_to<first_type, seq_last_type>());
59 }
60 };
61
62 struct use_default;
63
64 template <class T, class Default>
65 struct fusion_default_help
66 : mpl::if_<
67 is_same<T, use_default>
68 , Default
69 , T
70 >
71 {
72 };
73
74 template <
75 typename Sequence
76 , typename First
77 , typename Last = use_default>
78 struct erase
79 {
80 typedef typename result_of::begin<Sequence>::type seq_first_type;
81 typedef typename result_of::end<Sequence>::type seq_last_type;
82 BOOST_STATIC_ASSERT((!result_of::equal_to<seq_first_type, seq_last_type>::value));
83
84 typedef First FirstType;
85 typedef typename
86 fusion_default_help<
87 Last
88 , typename compute_erase_last<Sequence, First>::type
89 >::type
90 LastType;
91
92 typedef typename convert_iterator<FirstType>::type first_type;
93 typedef typename convert_iterator<LastType>::type last_type;
94 typedef iterator_range<seq_first_type, first_type> left_type;
95 typedef iterator_range<last_type, seq_last_type> right_type;
96 typedef joint_view<left_type, right_type> type;
97 };
98 }
99
100 template <typename Sequence, typename First>
101 BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
102 inline typename
103 lazy_enable_if<
104 traits::is_sequence<Sequence>
105 , typename result_of::erase<Sequence const, First>
106 >::type
107 erase(Sequence const& seq, First const& first)
108 {
109 typedef result_of::erase<Sequence const, First> result_of;
110 typedef typename result_of::left_type left_type;
111 typedef typename result_of::right_type right_type;
112 typedef typename result_of::type result_type;
113
114 left_type left(
115 fusion::begin(seq)
116 , convert_iterator<First>::call(first));
117 right_type right(
118 fusion::result_of::compute_erase_last<Sequence const, First>::call(first)
119 , fusion::end(seq));
120 return result_type(left, right);
121 }
122
123 template <typename Sequence, typename First, typename Last>
124 BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
125 inline typename result_of::erase<Sequence const, First, Last>::type
126 erase(Sequence const& seq, First const& first, Last const& last)
127 {
128 typedef result_of::erase<Sequence const, First, Last> result_of;
129 typedef typename result_of::left_type left_type;
130 typedef typename result_of::right_type right_type;
131 typedef typename result_of::type result_type;
132
133 left_type left(fusion::begin(seq), first);
134 right_type right(last, fusion::end(seq));
135 return result_type(left, right);
136 }
137}}
138
139#endif
140
141

source code of include/boost/fusion/algorithm/transformation/erase.hpp