json/detail/stack.hpp

0001 //
0002 // Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
0003 //
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // Official repository: https://github.com/boostorg/json
0008 //
0009
0010 #ifndef BOOST_JSON_DETAIL_STACK_HPP
0011 #define BOOST_JSON_DETAIL_STACK_HPP
0012
0013 #include <boost/json/detail/config.hpp>
0014 #include <boost/json/storage_ptr.hpp>
0015 #include <boost/mp11/integral.hpp>
0016 #include <cstring>
0017 #include <type_traits>
0018
0019 namespace boost {
0020 namespace json {
0021 namespace detail {
0022
0023 #if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
0024
0025 template<class T>
0026 struct is_trivially_copy_assignable
0027     : mp11::mp_bool<
0028         std::is_copy_assignable<T>::value &&
0029           std::has_trivial_copy_assign<T>::value >
0030 {};
0031
0032 #else
0033
0034 using std::is_trivially_copy_assignable;
0035
0036 #endif
0037
0038 class stack
0039 {
0040     template< class T = void >
0041     struct non_trivial;
0042
0043     storage_ptr sp_;
0044     std::size_t cap_ = 0;
0045     std::size_t size_ = 0;
0046     non_trivial<>* head_ = nullptr;
0047     unsigned char* base_ = nullptr;
0048     unsigned char* buf_ = nullptr;
0049
0050 public:
0051     BOOST_JSON_DECL
0052     ~stack();
0053
0054     stack() = default;
0055
0056     stack(
0057         storage_ptr sp,
0058         unsigned char* buf,
0059         std::size_t buf_size) noexcept;
0060
0061     bool
0062     empty() const noexcept
0063     {
0064         return size_ == 0;
0065     }
0066
0067     BOOST_JSON_DECL
0068     void
0069     clear() noexcept;
0070
0071     void
0072     reserve(std::size_t n)
0073     {
0074         if(n > cap_)
0075             reserve_impl(n);
0076     }
0077
0078     template<class T>
0079     void
0080     push(T&& t)
0081     {
0082         using U = remove_cvref<T>;
0083         push( static_cast<T&&>(t), is_trivially_copy_assignable<U>() );
0084     }
0085
0086     template<class T>
0087     void
0088     push_unchecked(
0089         T const& t);
0090
0091     template<class T>
0092     void
0093     peek(T& t);
0094
0095     template<class T>
0096     void
0097     pop(T& t)
0098     {
0099         using U = remove_cvref<T>;
0100         pop( t, is_trivially_copy_assignable<U>() );
0101     }
0102
0103 private:
0104     template<class T> void push(
0105         T const& t, std::true_type);
0106     template<class T> void push(
0107         T&& t, std::false_type);
0108     template<class T> void pop(
0109         T& t, std::true_type);
0110     template<class T> void pop(
0111         T& t, std::false_type);
0112
0113     BOOST_JSON_DECL
0114     void
0115     reserve_impl(
0116         std::size_t n);
0117 };
0118
0119 } // detail
0120 } // namespace json
0121 } // namespace boost
0122
0123 #include <boost/json/detail/impl/stack.hpp>
0124
0125 #endif