forked from ningnawang/QMAT
-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathfunction_input_iterator.hpp
More file actions
180 lines (152 loc) · 5.78 KB
/
Copy pathfunction_input_iterator.hpp
File metadata and controls
180 lines (152 loc) · 5.78 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
// Copyright 2009 (C) Dean Michael Berris <me@deanberris.com>
// Copyright 2012 (C) Google, Inc.
// Copyright 2012 (C) Jeffrey Lee Hellrung, Jr.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOST_FUNCTION_INPUT_ITERATOR
#define BOOST_FUNCTION_INPUT_ITERATOR
#include <boost/config.hpp>
#include <boost/assert.hpp>
#include <boost/core/addressof.hpp>
#include <boost/type_traits/conditional.hpp>
#include <boost/function_types/is_function_pointer.hpp>
#include <boost/function_types/result_type.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/none.hpp>
#include <boost/optional/optional.hpp>
#include <boost/utility/result_of.hpp>
#ifdef BOOST_RESULT_OF_USE_TR1
#include <boost/type_traits/is_function.hpp>
#endif
namespace boost {
namespace iterators {
template <class Function, class Input>
class function_input_iterator;
namespace impl {
// Computes the return type of an lvalue-call with an empty argument,
// i.e. decltype(declval<F&>()()). F should be a nullary lvalue-callable
// or function.
template <class F>
struct result_of_nullary_lvalue_call
{
typedef typename result_of<
#ifdef BOOST_RESULT_OF_USE_TR1
typename boost::conditional<is_function<F>::value, F&, F>::type()
#else
F&()
#endif
>::type type;
};
template <class Function, class Input>
class function_object_input_iterator :
public iterator_facade<
iterators::function_input_iterator<Function, Input>,
typename result_of_nullary_lvalue_call<Function>::type,
single_pass_traversal_tag,
typename result_of_nullary_lvalue_call<Function>::type const &
>
{
public:
function_object_input_iterator() {}
function_object_input_iterator(Function & f_, Input state_ = Input())
: f(boost::addressof(f_)), state(state_) {}
void increment() {
if (value)
value = none;
else
(*f)();
++state;
}
typename result_of_nullary_lvalue_call<Function>::type const &
dereference() const {
if (!value)
value = (*f)();
return value.get();
}
bool equal(function_object_input_iterator const & other) const {
return f == other.f && state == other.state;
}
private:
Function * f;
Input state;
mutable optional<typename result_of_nullary_lvalue_call<Function>::type> value;
};
template <class Function, class Input>
class function_pointer_input_iterator :
public iterator_facade<
iterators::function_input_iterator<Function, Input>,
typename function_types::result_type<Function>::type,
single_pass_traversal_tag,
typename function_types::result_type<Function>::type const &
>
{
public:
function_pointer_input_iterator() {}
function_pointer_input_iterator(Function &f_, Input state_ = Input())
: f(f_), state(state_) {}
void increment() {
if (value)
value = none;
else
(*f)();
++state;
}
typename function_types::result_type<Function>::type const &
dereference() const {
if (!value)
value = (*f)();
return value.get();
}
bool equal(function_pointer_input_iterator const & other) const {
return f == other.f && state == other.state;
}
private:
Function f;
Input state;
mutable optional<typename function_types::result_type<Function>::type> value;
};
} // namespace impl
template <class Function, class Input>
class function_input_iterator :
public boost::conditional<
function_types::is_function_pointer<Function>::value,
impl::function_pointer_input_iterator<Function,Input>,
impl::function_object_input_iterator<Function,Input>
>::type
{
typedef typename boost::conditional<
function_types::is_function_pointer<Function>::value,
impl::function_pointer_input_iterator<Function,Input>,
impl::function_object_input_iterator<Function,Input>
>::type base_type;
public:
function_input_iterator(Function & f, Input i)
: base_type(f, i) {}
};
template <class Function, class Input>
inline function_input_iterator<Function, Input>
make_function_input_iterator(Function & f, Input state) {
typedef function_input_iterator<Function, Input> result_t;
return result_t(f, state);
}
template <class Function, class Input>
inline function_input_iterator<Function*, Input>
make_function_input_iterator(Function * f, Input state) {
typedef function_input_iterator<Function*, Input> result_t;
return result_t(f, state);
}
struct infinite
{
infinite & operator++() { return *this; }
infinite & operator++(int) { return *this; }
bool operator==(infinite &) const { return false; };
bool operator==(infinite const &) const { return false; };
};
} // namespace iterators
using iterators::function_input_iterator;
using iterators::make_function_input_iterator;
using iterators::infinite;
} // namespace boost
#endif