ceph/src/boost/libs/type_index/include/boost/type_index/ctti_type_index.hpp

   1 //
   2 // Copyright (c) Antony Polukhin, 2013-2016.
   3 //
   4 //
   5 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   6 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8
   9 #ifndef BOOST_TYPE_INDEX_CTTI_TYPE_INDEX_HPP
  10 #define BOOST_TYPE_INDEX_CTTI_TYPE_INDEX_HPP
  11
  12 /// \file ctti_type_index.hpp
  13 /// \brief Contains boost::typeindex::ctti_type_index class that is constexpr if C++14 constexpr is supported by compiler.
  14 ///
  15 /// boost::typeindex::ctti_type_index class can be used as a drop-in replacement
  16 /// for std::type_index.
  17 ///
  18 /// It is used in situations when typeid() method is not available or
  19 /// BOOST_TYPE_INDEX_FORCE_NO_RTTI_COMPATIBILITY macro is defined.
  20
  21 #include <boost/type_index/type_index_facade.hpp>
  22 #include <boost/type_index/detail/compile_time_type_info.hpp>
  23
  24 #include <cstring>
  25 #include <boost/static_assert.hpp>
  26 #include <boost/type_traits/remove_cv.hpp>
  27 #include <boost/type_traits/remove_reference.hpp>
  28
  29 #ifdef BOOST_HAS_PRAGMA_ONCE
  30 # pragma once
  31 #endif
  32
  33 namespace boost { namespace typeindex {
  34
  35 namespace detail {
  36
  37 // That's the most trickiest part of the TypeIndex library:
  38 //      1) we do not want to give user ability to manually construct and compare `struct-that-represents-type`
  39 //      2) we need to distinguish between `struct-that-represents-type` and `const char*`
  40 //      3) we need a thread-safe way to have references to instances `struct-that-represents-type`
  41 //      4) we need a compile-time control to make sure that user does not copy or
  42 // default construct `struct-that-represents-type`
  43 //
  44 // Solution would be the following:
  45
  46 /// \class ctti_data
  47 /// Standard-layout class with private constructors and assignment operators.
  48 ///
  49 /// You can not work with this class directly. The  purpose of this class is to hold type info
  50 /// \b when \b RTTI \b is \b off and allow ctti_type_index construction from itself.
  51 ///
  52 /// \b Example:
  53 /// \code
  54 /// const detail::ctti_data& foo();
  55 /// ...
  56 /// type_index ti = type_index(foo());
  57 /// std::cout << ti.pretty_name();
  58 /// \endcode
  59 class ctti_data {
  60 #ifndef BOOST_NO_CXX11_DELETED_FUNCTIONS
  61 public:
  62     ctti_data() = delete;
  63     ctti_data(const ctti_data&) = delete;
  64     ctti_data& operator=(const ctti_data&) = delete;
  65 #else
  66 private:
  67     ctti_data();
  68     ctti_data(const ctti_data&);
  69     ctti_data& operator=(const ctti_data&);
  70 #endif
  71 };
  72
  73 } // namespace detail
  74
  75 /// Helper method for getting detail::ctti_data of a template parameter T.
  76 template <class T>
  77 inline const detail::ctti_data& ctti_construct() BOOST_NOEXCEPT {
  78     // Standard C++11, 5.2.10 Reinterpret cast:
  79     // An object pointer can be explicitly converted to an object pointer of a different type. When a prvalue
  80     // v of type "pointer to T1" is converted to the type "pointer to cv T2", the result is static_cast<cv
  81     // T2*>(static_cast<cv void*>(v)) if both T1 and T2 are standard-layout types (3.9) and the alignment
  82     // requirements of T2 are no stricter than those of T1, or if either type is void. Converting a prvalue of type
  83     // "pointer to T1" to the type "pointer to T2" (where T1 and T2 are object types and where the alignment
  84     // requirements of T2 are no stricter than those of T1) and back to its original type yields the original pointer
  85     // value.
  86     //
  87     // Alignments are checked in `type_index_test_ctti_alignment.cpp` test.
  88     return *reinterpret_cast<const detail::ctti_data*>(boost::detail::ctti<T>::n());
  89 }
  90
  91 /// \class ctti_type_index
  92 /// This class is a wrapper that pretends to work exactly like stl_type_index, but does
  93 /// not require RTTI support. \b For \b description \b of \b functions \b see type_index_facade.
  94 ///
  95 /// This class on C++14 compatible compilers has following functions marked as constexpr:
  96 ///     * default constructor
  97 ///     * copy constructors and assignemnt operations
  98 ///     * class methods: name(), before(const ctti_type_index& rhs), equal(const ctti_type_index& rhs)
  99 ///     * static methods type_id<T>(), type_id_with_cvr<T>()
 100 ///     * comparison operators
 101 ///
 102 /// This class produces slightly longer type names, so consider using stl_type_index
 103 /// in situations when typeid() is working.
 104 class ctti_type_index: public type_index_facade<ctti_type_index, detail::ctti_data> {
 105     const char* data_;
 106
 107     inline std::size_t get_raw_name_length() const BOOST_NOEXCEPT;
 108
 109     BOOST_CXX14_CONSTEXPR inline explicit ctti_type_index(const char* data) BOOST_NOEXCEPT
 110         : data_(data)
 111     {}
 112
 113 public:
 114     typedef detail::ctti_data type_info_t;
 115
 116     BOOST_CXX14_CONSTEXPR inline ctti_type_index() BOOST_NOEXCEPT
 117         : data_(boost::detail::ctti<void>::n())
 118     {}
 119
 120     inline ctti_type_index(const type_info_t& data) BOOST_NOEXCEPT
 121         : data_(reinterpret_cast<const char*>(&data))
 122     {}
 123
 124     inline const type_info_t& type_info() const BOOST_NOEXCEPT;
 125     BOOST_CXX14_CONSTEXPR inline const char* raw_name() const BOOST_NOEXCEPT;
 126     BOOST_CXX14_CONSTEXPR inline const char* name() const BOOST_NOEXCEPT;
 127     inline std::string  pretty_name() const;
 128     inline std::size_t  hash_code() const BOOST_NOEXCEPT;
 129
 130     BOOST_CXX14_CONSTEXPR inline bool equal(const ctti_type_index& rhs) const BOOST_NOEXCEPT;
 131     BOOST_CXX14_CONSTEXPR inline bool before(const ctti_type_index& rhs) const BOOST_NOEXCEPT;
 132
 133     template <class T>
 134     BOOST_CXX14_CONSTEXPR inline static ctti_type_index type_id() BOOST_NOEXCEPT;
 135
 136     template <class T>
 137     BOOST_CXX14_CONSTEXPR inline static ctti_type_index type_id_with_cvr() BOOST_NOEXCEPT;
 138
 139     template <class T>
 140     inline static ctti_type_index type_id_runtime(const T& variable) BOOST_NOEXCEPT;
 141 };
 142
 143
 144 inline const ctti_type_index::type_info_t& ctti_type_index::type_info() const BOOST_NOEXCEPT {
 145     return *reinterpret_cast<const detail::ctti_data*>(data_);
 146 }
 147
 148
 149 BOOST_CXX14_CONSTEXPR inline bool ctti_type_index::equal(const ctti_type_index& rhs) const BOOST_NOEXCEPT {
 150     const char* const left = raw_name();
 151     const char* const right = rhs.raw_name();
 152     return /*left == right ||*/ !boost::typeindex::detail::constexpr_strcmp(left, right);
 153 }
 154
 155 BOOST_CXX14_CONSTEXPR inline bool ctti_type_index::before(const ctti_type_index& rhs) const BOOST_NOEXCEPT {
 156     const char* const left = raw_name();
 157     const char* const right = rhs.raw_name();
 158     return /*left != right &&*/ boost::typeindex::detail::constexpr_strcmp(left, right) < 0;
 159 }
 160
 161
 162 template <class T>
 163 BOOST_CXX14_CONSTEXPR inline ctti_type_index ctti_type_index::type_id() BOOST_NOEXCEPT {
 164     typedef BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type no_ref_t;
 165     typedef BOOST_DEDUCED_TYPENAME boost::remove_cv<no_ref_t>::type no_cvr_t;
 166     return ctti_type_index(boost::detail::ctti<no_cvr_t>::n());
 167 }
 168
 169
 170
 171 template <class T>
 172 BOOST_CXX14_CONSTEXPR inline ctti_type_index ctti_type_index::type_id_with_cvr() BOOST_NOEXCEPT {
 173     return ctti_type_index(boost::detail::ctti<T>::n());
 174 }
 175
 176
 177 template <class T>
 178 inline ctti_type_index ctti_type_index::type_id_runtime(const T& variable) BOOST_NOEXCEPT {
 179     return variable.boost_type_index_type_id_runtime_();
 180 }
 181
 182
 183 BOOST_CXX14_CONSTEXPR inline const char* ctti_type_index::raw_name() const BOOST_NOEXCEPT {
 184     return data_;
 185 }
 186
 187
 188 BOOST_CXX14_CONSTEXPR inline const char* ctti_type_index::name() const BOOST_NOEXCEPT {
 189     return data_;
 190 }
 191
 192 inline std::size_t ctti_type_index::get_raw_name_length() const BOOST_NOEXCEPT {
 193     return std::strlen(raw_name() + detail::ctti_skip_size_at_end);
 194 }
 195
 196
 197 inline std::string ctti_type_index::pretty_name() const {
 198     std::size_t len = get_raw_name_length();
 199     while (raw_name()[len - 1] == ' ') --len; // MSVC sometimes adds whitespaces
 200     return std::string(raw_name(), len);
 201 }
 202
 203
 204 inline std::size_t ctti_type_index::hash_code() const BOOST_NOEXCEPT {
 205     return boost::hash_range(raw_name(), raw_name() + get_raw_name_length());
 206 }
 207
 208
 209 }} // namespace boost::typeindex
 210
 211 #endif // BOOST_TYPE_INDEX_CTTI_TYPE_INDEX_HPP
 212