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92f5a8d4 | 1 | /* Copyright 2016-2019 Joaquin M Lopez Munoz. |
b32b8144 FG |
2 | * Distributed under the Boost Software License, Version 1.0. |
3 | * (See accompanying file LICENSE_1_0.txt or copy at | |
4 | * http://www.boost.org/LICENSE_1_0.txt) | |
5 | * | |
6 | * See http://www.boost.org/libs/poly_collection for library home page. | |
7 | */ | |
8 | ||
9 | #ifndef BOOST_POLY_COLLECTION_DETAIL_STRIDE_ITERATOR_HPP | |
10 | #define BOOST_POLY_COLLECTION_DETAIL_STRIDE_ITERATOR_HPP | |
11 | ||
12 | #if defined(_MSC_VER) | |
13 | #pragma once | |
14 | #endif | |
15 | ||
92f5a8d4 | 16 | #include <boost/detail/workaround.hpp> |
b32b8144 FG |
17 | #include <boost/iterator/iterator_facade.hpp> |
18 | #include <type_traits> | |
19 | ||
20 | namespace boost{ | |
21 | ||
22 | namespace poly_collection{ | |
23 | ||
24 | namespace detail{ | |
25 | ||
26 | /* random-access iterator to Value elements laid out stride *chars* apart */ | |
27 | ||
28 | template<typename Value> | |
29 | class stride_iterator: | |
30 | public boost::iterator_facade< | |
31 | stride_iterator<Value>, | |
32 | Value, | |
33 | boost::random_access_traversal_tag | |
34 | > | |
35 | { | |
36 | public: | |
37 | stride_iterator()=default; | |
38 | stride_iterator(Value* p,std::size_t stride)noexcept:p{p},stride_{stride}{} | |
39 | stride_iterator(const stride_iterator&)=default; | |
40 | stride_iterator& operator=(const stride_iterator&)=default; | |
41 | ||
42 | template< | |
43 | typename NonConstValue, | |
44 | typename std::enable_if< | |
45 | std::is_same<Value,const NonConstValue>::value>::type* =nullptr | |
46 | > | |
47 | stride_iterator(const stride_iterator<NonConstValue>& x)noexcept: | |
48 | p{x.p},stride_{x.stride_}{} | |
49 | ||
50 | template< | |
51 | typename NonConstValue, | |
52 | typename std::enable_if< | |
53 | std::is_same<Value,const NonConstValue>::value>::type* =nullptr | |
54 | > | |
55 | stride_iterator& operator=(const stride_iterator<NonConstValue>& x)noexcept | |
56 | { | |
57 | p=x.p;stride_=x.stride_; | |
58 | return *this; | |
59 | } | |
60 | ||
61 | /* interoperability with [Derived]Value* */ | |
62 | ||
63 | stride_iterator& operator=(Value* p_)noexcept{p=p_;return *this;} | |
64 | operator Value*()const noexcept{return p;} | |
65 | ||
66 | template< | |
67 | typename DerivedValue, | |
68 | typename std::enable_if< | |
69 | std::is_base_of<Value,DerivedValue>::value&& | |
70 | (std::is_const<Value>::value||!std::is_const<DerivedValue>::value) | |
71 | >::type* =nullptr | |
72 | > | |
73 | explicit stride_iterator(DerivedValue* x)noexcept: | |
74 | p{x},stride_{sizeof(DerivedValue)}{} | |
75 | ||
92f5a8d4 TL |
76 | #if BOOST_WORKAROUND(BOOST_GCC_VERSION,>=40900)||\ |
77 | BOOST_WORKAROUND(BOOST_CLANG,>=1)&&\ | |
78 | (__clang_major__>3 || __clang_major__==3 && __clang_minor__ >= 8) | |
79 | /* https://github.com/boostorg/poly_collection/issues/15 */ | |
80 | ||
81 | #define BOOST_POLY_COLLECTION_NO_SANITIZE | |
82 | ||
83 | /* UBSan seems not to be supported in some environments */ | |
84 | #if defined(BOOST_GCC_VERSION) | |
85 | #pragma GCC diagnostic push | |
86 | #pragma GCC diagnostic ignored "-Wattributes" | |
87 | #elif defined(BOOST_CLANG) | |
88 | #pragma clang diagnostic push | |
89 | #pragma clang diagnostic ignored "-Wattributes" | |
90 | #endif | |
91 | #endif | |
92 | ||
b32b8144 FG |
93 | template< |
94 | typename DerivedValue, | |
95 | typename std::enable_if< | |
96 | std::is_base_of<Value,DerivedValue>::value&& | |
97 | (!std::is_const<Value>::value||std::is_const<DerivedValue>::value) | |
98 | >::type* =nullptr | |
99 | > | |
92f5a8d4 TL |
100 | #if defined(BOOST_POLY_COLLECTION_NO_SANITIZE) |
101 | __attribute__((no_sanitize("undefined"))) | |
102 | #endif | |
b32b8144 FG |
103 | explicit operator DerivedValue*()const noexcept |
104 | {return static_cast<DerivedValue*>(p);} | |
105 | ||
92f5a8d4 TL |
106 | #if defined(BOOST_POLY_COLLECTION_NO_SANITIZE) |
107 | #if defined(BOOST_GCC_VERSION) | |
108 | #pragma GCC diagnostic pop | |
109 | #elif defined(BOOST_CLANG) | |
110 | #pragma clang diagnostic pop | |
111 | #endif | |
112 | ||
113 | #undef BOOST_POLY_COLLECTION_NO_SANITIZE | |
114 | #endif | |
115 | ||
b32b8144 FG |
116 | std::size_t stride()const noexcept{return stride_;} |
117 | ||
118 | private: | |
119 | template<typename> | |
120 | friend class stride_iterator; | |
121 | ||
122 | using char_pointer=typename std::conditional< | |
123 | std::is_const<Value>::value, | |
124 | const char*, | |
125 | char* | |
126 | >::type; | |
127 | ||
128 | static char_pointer char_ptr(Value* p)noexcept | |
129 | {return reinterpret_cast<char_pointer>(p);} | |
130 | static Value* value_ptr(char_pointer p)noexcept | |
131 | {return reinterpret_cast<Value*>(p);} | |
132 | ||
133 | friend class boost::iterator_core_access; | |
134 | ||
135 | Value& dereference()const noexcept{return *p;} | |
136 | bool equal(const stride_iterator& x)const noexcept{return p==x.p;} | |
137 | void increment()noexcept{p=value_ptr(char_ptr(p)+stride_);} | |
138 | void decrement()noexcept{p=value_ptr(char_ptr(p)-stride_);} | |
139 | template<typename Integral> | |
11fdf7f2 TL |
140 | void advance(Integral n)noexcept |
141 | {p=value_ptr(char_ptr(p)+n*(std::ptrdiff_t)stride_);} | |
b32b8144 | 142 | std::ptrdiff_t distance_to(const stride_iterator& x)const noexcept |
11fdf7f2 | 143 | {return (char_ptr(x.p)-char_ptr(p))/(std::ptrdiff_t)stride_;} |
b32b8144 FG |
144 | |
145 | Value* p; | |
146 | std::size_t stride_; | |
147 | }; | |
148 | ||
149 | } /* namespace poly_collection::detail */ | |
150 | ||
151 | } /* namespace poly_collection */ | |
152 | ||
153 | } /* namespace boost */ | |
154 | ||
155 | #endif |