toml11/toml/comments.hpp
2021-04-16 15:28:58 +09:00

473 lines
20 KiB
C++

// Copyright Toru Niina 2019.
// Distributed under the MIT License.
#ifndef TOML11_COMMENTS_HPP
#define TOML11_COMMENTS_HPP
#include <initializer_list>
#include <iterator>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
#ifdef TOML11_PRESERVE_COMMENTS_BY_DEFAULT
# define TOML11_DEFAULT_COMMENT_STRATEGY ::toml::preserve_comments
#else
# define TOML11_DEFAULT_COMMENT_STRATEGY ::toml::discard_comments
#endif
// This file provides mainly two classes, `preserve_comments` and `discard_comments`.
// Those two are a container that have the same interface as `std::vector<std::string>`
// but bahaves in the opposite way. `preserve_comments` is just the same as
// `std::vector<std::string>` and each `std::string` corresponds to a comment line.
// Conversely, `discard_comments` discards all the strings and ignores everything
// assigned in it. `discard_comments` is always empty and you will encounter an
// error whenever you access to the element.
namespace toml
{
struct discard_comments; // forward decl
// use it in the following way
//
// const toml::basic_value<toml::preserve_comments> data =
// toml::parse<toml::preserve_comments>("example.toml");
//
// the interface is almost the same as std::vector<std::string>.
struct preserve_comments
{
// `container_type` is not provided in discard_comments.
// do not use this inner-type in a generic code.
using container_type = std::vector<std::string>;
using size_type = container_type::size_type;
using difference_type = container_type::difference_type;
using value_type = container_type::value_type;
using reference = container_type::reference;
using const_reference = container_type::const_reference;
using pointer = container_type::pointer;
using const_pointer = container_type::const_pointer;
using iterator = container_type::iterator;
using const_iterator = container_type::const_iterator;
using reverse_iterator = container_type::reverse_iterator;
using const_reverse_iterator = container_type::const_reverse_iterator;
preserve_comments() = default;
~preserve_comments() = default;
preserve_comments(preserve_comments const&) = default;
preserve_comments(preserve_comments &&) = default;
preserve_comments& operator=(preserve_comments const&) = default;
preserve_comments& operator=(preserve_comments &&) = default;
explicit preserve_comments(const std::vector<std::string>& c): comments(c){}
explicit preserve_comments(std::vector<std::string>&& c)
: comments(std::move(c))
{}
preserve_comments& operator=(const std::vector<std::string>& c)
{
comments = c;
return *this;
}
preserve_comments& operator=(std::vector<std::string>&& c)
{
comments = std::move(c);
return *this;
}
explicit preserve_comments(const discard_comments&) {}
explicit preserve_comments(size_type n): comments(n) {}
preserve_comments(size_type n, const std::string& x): comments(n, x) {}
preserve_comments(std::initializer_list<std::string> x): comments(x) {}
template<typename InputIterator>
preserve_comments(InputIterator first, InputIterator last)
: comments(first, last)
{}
template<typename InputIterator>
void assign(InputIterator first, InputIterator last) {comments.assign(first, last);}
void assign(std::initializer_list<std::string> ini) {comments.assign(ini);}
void assign(size_type n, const std::string& val) {comments.assign(n, val);}
// Related to the issue #97.
//
// It is known that `std::vector::insert` and `std::vector::erase` in
// the standard library implementation included in GCC 4.8.5 takes
// `std::vector::iterator` instead of `std::vector::const_iterator`.
// Because of the const-correctness, we cannot convert a `const_iterator` to
// an `iterator`. It causes compilation error in GCC 4.8.5.
#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__) && !defined(__clang__)
# if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) <= 40805
# define TOML11_WORKAROUND_GCC_4_8_X_STANDARD_LIBRARY_IMPLEMENTATION
# endif
#endif
#ifdef TOML11_WORKAROUND_GCC_4_8_X_STANDARD_LIBRARY_IMPLEMENTATION
iterator insert(iterator p, const std::string& x)
{
return comments.insert(p, x);
}
iterator insert(iterator p, std::string&& x)
{
return comments.insert(p, std::move(x));
}
void insert(iterator p, size_type n, const std::string& x)
{
return comments.insert(p, n, x);
}
template<typename InputIterator>
void insert(iterator p, InputIterator first, InputIterator last)
{
return comments.insert(p, first, last);
}
void insert(iterator p, std::initializer_list<std::string> ini)
{
return comments.insert(p, ini);
}
template<typename ... Ts>
iterator emplace(iterator p, Ts&& ... args)
{
return comments.emplace(p, std::forward<Ts>(args)...);
}
iterator erase(iterator pos) {return comments.erase(pos);}
iterator erase(iterator first, iterator last)
{
return comments.erase(first, last);
}
#else
iterator insert(const_iterator p, const std::string& x)
{
return comments.insert(p, x);
}
iterator insert(const_iterator p, std::string&& x)
{
return comments.insert(p, std::move(x));
}
iterator insert(const_iterator p, size_type n, const std::string& x)
{
return comments.insert(p, n, x);
}
template<typename InputIterator>
iterator insert(const_iterator p, InputIterator first, InputIterator last)
{
return comments.insert(p, first, last);
}
iterator insert(const_iterator p, std::initializer_list<std::string> ini)
{
return comments.insert(p, ini);
}
template<typename ... Ts>
iterator emplace(const_iterator p, Ts&& ... args)
{
return comments.emplace(p, std::forward<Ts>(args)...);
}
iterator erase(const_iterator pos) {return comments.erase(pos);}
iterator erase(const_iterator first, const_iterator last)
{
return comments.erase(first, last);
}
#endif
void swap(preserve_comments& other) {comments.swap(other.comments);}
void push_back(const std::string& v) {comments.push_back(v);}
void push_back(std::string&& v) {comments.push_back(std::move(v));}
void pop_back() {comments.pop_back();}
template<typename ... Ts>
void emplace_back(Ts&& ... args) {comments.emplace_back(std::forward<Ts>(args)...);}
void clear() {comments.clear();}
size_type size() const noexcept {return comments.size();}
size_type max_size() const noexcept {return comments.max_size();}
size_type capacity() const noexcept {return comments.capacity();}
bool empty() const noexcept {return comments.empty();}
void reserve(size_type n) {comments.reserve(n);}
void resize(size_type n) {comments.resize(n);}
void resize(size_type n, const std::string& c) {comments.resize(n, c);}
void shrink_to_fit() {comments.shrink_to_fit();}
reference operator[](const size_type n) noexcept {return comments[n];}
const_reference operator[](const size_type n) const noexcept {return comments[n];}
reference at(const size_type n) {return comments.at(n);}
const_reference at(const size_type n) const {return comments.at(n);}
reference front() noexcept {return comments.front();}
const_reference front() const noexcept {return comments.front();}
reference back() noexcept {return comments.back();}
const_reference back() const noexcept {return comments.back();}
pointer data() noexcept {return comments.data();}
const_pointer data() const noexcept {return comments.data();}
iterator begin() noexcept {return comments.begin();}
iterator end() noexcept {return comments.end();}
const_iterator begin() const noexcept {return comments.begin();}
const_iterator end() const noexcept {return comments.end();}
const_iterator cbegin() const noexcept {return comments.cbegin();}
const_iterator cend() const noexcept {return comments.cend();}
reverse_iterator rbegin() noexcept {return comments.rbegin();}
reverse_iterator rend() noexcept {return comments.rend();}
const_reverse_iterator rbegin() const noexcept {return comments.rbegin();}
const_reverse_iterator rend() const noexcept {return comments.rend();}
const_reverse_iterator crbegin() const noexcept {return comments.crbegin();}
const_reverse_iterator crend() const noexcept {return comments.crend();}
friend bool operator==(const preserve_comments&, const preserve_comments&);
friend bool operator!=(const preserve_comments&, const preserve_comments&);
friend bool operator< (const preserve_comments&, const preserve_comments&);
friend bool operator<=(const preserve_comments&, const preserve_comments&);
friend bool operator> (const preserve_comments&, const preserve_comments&);
friend bool operator>=(const preserve_comments&, const preserve_comments&);
friend void swap(preserve_comments&, std::vector<std::string>&);
friend void swap(std::vector<std::string>&, preserve_comments&);
private:
container_type comments;
};
inline bool operator==(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments == rhs.comments;}
inline bool operator!=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments != rhs.comments;}
inline bool operator< (const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments < rhs.comments;}
inline bool operator<=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments <= rhs.comments;}
inline bool operator> (const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments > rhs.comments;}
inline bool operator>=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments >= rhs.comments;}
inline void swap(preserve_comments& lhs, preserve_comments& rhs)
{
lhs.swap(rhs);
return;
}
inline void swap(preserve_comments& lhs, std::vector<std::string>& rhs)
{
lhs.comments.swap(rhs);
return;
}
inline void swap(std::vector<std::string>& lhs, preserve_comments& rhs)
{
lhs.swap(rhs.comments);
return;
}
template<typename charT, typename traits>
std::basic_ostream<charT, traits>&
operator<<(std::basic_ostream<charT, traits>& os, const preserve_comments& com)
{
for(const auto& c : com)
{
os << '#' << c << '\n';
}
return os;
}
namespace detail
{
// To provide the same interface with `preserve_comments`, `discard_comments`
// should have an iterator. But it does not contain anything, so we need to
// add an iterator that points nothing.
//
// It always points null, so DO NOT unwrap this iterator. It always crashes
// your program.
template<typename T, bool is_const>
struct empty_iterator
{
using value_type = T;
using reference_type = typename std::conditional<is_const, T const&, T&>::type;
using pointer_type = typename std::conditional<is_const, T const*, T*>::type;
using difference_type = std::ptrdiff_t;
using iterator_category = std::random_access_iterator_tag;
empty_iterator() = default;
~empty_iterator() = default;
empty_iterator(empty_iterator const&) = default;
empty_iterator(empty_iterator &&) = default;
empty_iterator& operator=(empty_iterator const&) = default;
empty_iterator& operator=(empty_iterator &&) = default;
// DO NOT call these operators.
reference_type operator*() const noexcept {std::terminate();}
pointer_type operator->() const noexcept {return nullptr;}
reference_type operator[](difference_type) const noexcept {return this->operator*();}
// These operators do nothing.
empty_iterator& operator++() noexcept {return *this;}
empty_iterator operator++(int) noexcept {return *this;}
empty_iterator& operator--() noexcept {return *this;}
empty_iterator operator--(int) noexcept {return *this;}
empty_iterator& operator+=(difference_type) noexcept {return *this;}
empty_iterator& operator-=(difference_type) noexcept {return *this;}
empty_iterator operator+(difference_type) const noexcept {return *this;}
empty_iterator operator-(difference_type) const noexcept {return *this;}
};
template<typename T, bool C>
bool operator==(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
template<typename T, bool C>
bool operator!=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
template<typename T, bool C>
bool operator< (const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
template<typename T, bool C>
bool operator<=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
template<typename T, bool C>
bool operator> (const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
template<typename T, bool C>
bool operator>=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
template<typename T, bool C>
typename empty_iterator<T, C>::difference_type
operator-(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return 0;}
template<typename T, bool C>
empty_iterator<T, C>
operator+(typename empty_iterator<T, C>::difference_type, const empty_iterator<T, C>& rhs) noexcept {return rhs;}
template<typename T, bool C>
empty_iterator<T, C>
operator+(const empty_iterator<T, C>& lhs, typename empty_iterator<T, C>::difference_type) noexcept {return lhs;}
} // detail
// The default comment type. It discards all the comments. It requires only one
// byte to contain, so the memory footprint is smaller than preserve_comments.
//
// It just ignores `push_back`, `insert`, `erase`, and any other modifications.
// IT always returns size() == 0, the iterator taken by `begin()` is always the
// same as that of `end()`, and accessing through `operator[]` or iterators
// always causes a segmentation fault. DO NOT access to the element of this.
//
// Why this is chose as the default type is because the last version (2.x.y)
// does not contain any comments in a value. To minimize the impact on the
// efficiency, this is choosed as a default.
//
// To reduce the memory footprint, later we can try empty base optimization (EBO).
struct discard_comments
{
using size_type = std::size_t;
using difference_type = std::ptrdiff_t;
using value_type = std::string;
using reference = std::string&;
using const_reference = std::string const&;
using pointer = std::string*;
using const_pointer = std::string const*;
using iterator = detail::empty_iterator<std::string, false>;
using const_iterator = detail::empty_iterator<std::string, true>;
using reverse_iterator = detail::empty_iterator<std::string, false>;
using const_reverse_iterator = detail::empty_iterator<std::string, true>;
discard_comments() = default;
~discard_comments() = default;
discard_comments(discard_comments const&) = default;
discard_comments(discard_comments &&) = default;
discard_comments& operator=(discard_comments const&) = default;
discard_comments& operator=(discard_comments &&) = default;
explicit discard_comments(const std::vector<std::string>&) noexcept {}
explicit discard_comments(std::vector<std::string>&&) noexcept {}
discard_comments& operator=(const std::vector<std::string>&) noexcept {return *this;}
discard_comments& operator=(std::vector<std::string>&&) noexcept {return *this;}
explicit discard_comments(const preserve_comments&) noexcept {}
explicit discard_comments(size_type) noexcept {}
discard_comments(size_type, const std::string&) noexcept {}
discard_comments(std::initializer_list<std::string>) noexcept {}
template<typename InputIterator>
discard_comments(InputIterator, InputIterator) noexcept {}
template<typename InputIterator>
void assign(InputIterator, InputIterator) noexcept {}
void assign(std::initializer_list<std::string>) noexcept {}
void assign(size_type, const std::string&) noexcept {}
iterator insert(const_iterator, const std::string&) {return iterator{};}
iterator insert(const_iterator, std::string&&) {return iterator{};}
iterator insert(const_iterator, size_type, const std::string&) {return iterator{};}
template<typename InputIterator>
iterator insert(const_iterator, InputIterator, InputIterator) {return iterator{};}
iterator insert(const_iterator, std::initializer_list<std::string>) {return iterator{};}
template<typename ... Ts>
iterator emplace(const_iterator, Ts&& ...) {return iterator{};}
iterator erase(const_iterator) {return iterator{};}
iterator erase(const_iterator, const_iterator) {return iterator{};}
void swap(discard_comments&) {return;}
void push_back(const std::string&) {return;}
void push_back(std::string&& ) {return;}
void pop_back() {return;}
template<typename ... Ts>
void emplace_back(Ts&& ...) {return;}
void clear() {return;}
size_type size() const noexcept {return 0;}
size_type max_size() const noexcept {return 0;}
size_type capacity() const noexcept {return 0;}
bool empty() const noexcept {return true;}
void reserve(size_type) {return;}
void resize(size_type) {return;}
void resize(size_type, const std::string&) {return;}
void shrink_to_fit() {return;}
// DO NOT access to the element of this container. This container is always
// empty, so accessing through operator[], front/back, data causes address
// error.
reference operator[](const size_type) noexcept {return *data();}
const_reference operator[](const size_type) const noexcept {return *data();}
reference at(const size_type) {throw std::out_of_range("toml::discard_comment is always empty.");}
const_reference at(const size_type) const {throw std::out_of_range("toml::discard_comment is always empty.");}
reference front() noexcept {return *data();}
const_reference front() const noexcept {return *data();}
reference back() noexcept {return *data();}
const_reference back() const noexcept {return *data();}
pointer data() noexcept {return nullptr;}
const_pointer data() const noexcept {return nullptr;}
iterator begin() noexcept {return iterator{};}
iterator end() noexcept {return iterator{};}
const_iterator begin() const noexcept {return const_iterator{};}
const_iterator end() const noexcept {return const_iterator{};}
const_iterator cbegin() const noexcept {return const_iterator{};}
const_iterator cend() const noexcept {return const_iterator{};}
reverse_iterator rbegin() noexcept {return iterator{};}
reverse_iterator rend() noexcept {return iterator{};}
const_reverse_iterator rbegin() const noexcept {return const_iterator{};}
const_reverse_iterator rend() const noexcept {return const_iterator{};}
const_reverse_iterator crbegin() const noexcept {return const_iterator{};}
const_reverse_iterator crend() const noexcept {return const_iterator{};}
};
inline bool operator==(const discard_comments&, const discard_comments&) noexcept {return true;}
inline bool operator!=(const discard_comments&, const discard_comments&) noexcept {return false;}
inline bool operator< (const discard_comments&, const discard_comments&) noexcept {return false;}
inline bool operator<=(const discard_comments&, const discard_comments&) noexcept {return true;}
inline bool operator> (const discard_comments&, const discard_comments&) noexcept {return false;}
inline bool operator>=(const discard_comments&, const discard_comments&) noexcept {return true;}
inline void swap(const discard_comments&, const discard_comments&) noexcept {return;}
template<typename charT, typename traits>
std::basic_ostream<charT, traits>&
operator<<(std::basic_ostream<charT, traits>& os, const discard_comments&)
{
return os;
}
} // toml11
#endif// TOML11_COMMENTS_HPP