mirror of
https://github.com/fmtlib/fmt.git
synced 2024-11-07 17:41:11 +00:00
484 lines
15 KiB
C++
484 lines
15 KiB
C++
// Formatting library for C++ - experimental range support
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//
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// Copyright (c) 2012 - present, Victor Zverovich
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// All rights reserved.
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//
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// For the license information refer to format.h.
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//
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// Copyright (c) 2018 - present, Remotion (Igor Schulz)
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// All Rights Reserved
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// {fmt} support for ranges, containers and types tuple interface.
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#ifndef FMT_RANGES_H_
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#define FMT_RANGES_H_
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#include <initializer_list>
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#include <type_traits>
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#include "format.h"
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// output only up to N items from the range.
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#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
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# define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
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#endif
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FMT_BEGIN_NAMESPACE
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template <typename Char> struct formatting_base {
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
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return ctx.begin();
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}
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};
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template <typename Char, typename Enable = void>
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struct formatting_range : formatting_base<Char> {
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static FMT_CONSTEXPR_DECL const size_t range_length_limit =
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FMT_RANGE_OUTPUT_LENGTH_LIMIT; // output only up to N items from the
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// range.
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Char prefix;
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Char delimiter;
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Char postfix;
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formatting_range() : prefix('{'), delimiter(','), postfix('}') {}
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static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
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static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
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};
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template <typename Char, typename Enable = void>
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struct formatting_tuple : formatting_base<Char> {
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Char prefix;
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Char delimiter;
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Char postfix;
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formatting_tuple() : prefix('('), delimiter(','), postfix(')') {}
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static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
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static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
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};
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namespace detail {
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template <typename RangeT, typename OutputIterator>
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OutputIterator copy(const RangeT& range, OutputIterator out) {
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for (auto it = range.begin(), end = range.end(); it != end; ++it)
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*out++ = *it;
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return out;
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}
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template <typename OutputIterator>
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OutputIterator copy(const char* str, OutputIterator out) {
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while (*str) *out++ = *str++;
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return out;
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}
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template <typename OutputIterator>
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OutputIterator copy(char ch, OutputIterator out) {
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*out++ = ch;
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return out;
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}
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/// Return true value if T has std::string interface, like std::string_view.
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template <typename T> class is_like_std_string {
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template <typename U>
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static auto check(U* p)
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-> decltype((void)p->find('a'), p->length(), (void)p->data(), int());
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template <typename> static void check(...);
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public:
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static FMT_CONSTEXPR_DECL const bool value =
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is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value;
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};
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template <typename Char>
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struct is_like_std_string<fmt::basic_string_view<Char>> : std::true_type {};
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template <typename... Ts> struct conditional_helper {};
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template <typename T, typename _ = void> struct is_range_ : std::false_type {};
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#if !FMT_MSC_VER || FMT_MSC_VER > 1800
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# define FMT_DECLTYPE_RETURN(val) \
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->decltype(val) { return val; } \
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static_assert( \
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true, "") // This makes it so that a semicolon is required after the
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// macro, which helps clang-format handle the formatting.
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// C array overload
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template <typename T, std::size_t N>
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auto range_begin(const T (&arr)[N]) -> const T* {
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return arr;
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}
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template <typename T, std::size_t N>
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auto range_end(const T (&arr)[N]) -> const T* {
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return arr + N;
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}
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template <typename T, typename Enable = void>
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struct has_member_fn_begin_end_t : std::false_type {};
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template <typename T>
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struct has_member_fn_begin_end_t<T, void_t<decltype(std::declval<T>().begin()),
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decltype(std::declval<T>().end())>>
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: std::true_type {};
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// Member function overload
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template <typename T>
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auto range_begin(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).begin());
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template <typename T>
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auto range_end(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).end());
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// ADL overload. Only participates in overload resolution if member functions
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// are not found.
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template <typename T>
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auto range_begin(T&& rng)
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-> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
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decltype(begin(static_cast<T&&>(rng)))> {
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return begin(static_cast<T&&>(rng));
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}
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template <typename T>
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auto range_end(T&& rng) -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
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decltype(end(static_cast<T&&>(rng)))> {
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return end(static_cast<T&&>(rng));
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}
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template <typename T, typename Enable = void>
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struct has_const_begin_end : std::false_type {};
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template <typename T, typename Enable = void>
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struct has_mutable_begin_end : std::false_type {};
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template <typename T>
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struct has_const_begin_end<
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T, void_t<decltype(detail::range_begin(
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std::declval<const remove_cvref_t<T>&>())),
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decltype(detail::range_begin(
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std::declval<const remove_cvref_t<T>&>()))>>
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: std::true_type {};
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template <typename T>
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struct has_mutable_begin_end<
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T, void_t<decltype(detail::range_begin(std::declval<T>())),
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decltype(detail::range_begin(std::declval<T>())),
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enable_if_t<std::is_copy_constructible<T>::value>>>
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: std::true_type {};
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template <typename T>
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struct is_range_<T, void>
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: std::integral_constant<bool, (has_const_begin_end<T>::value ||
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has_mutable_begin_end<T>::value)> {};
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template <typename T, typename Enable = void> struct range_to_view;
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template <typename T>
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struct range_to_view<T, enable_if_t<has_const_begin_end<T>::value>> {
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struct view_t {
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const T* m_range_ptr;
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auto begin() const FMT_DECLTYPE_RETURN(detail::range_begin(*m_range_ptr));
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auto end() const FMT_DECLTYPE_RETURN(detail::range_end(*m_range_ptr));
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};
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static auto view(const T& range) -> view_t { return {&range}; }
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};
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template <typename T>
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struct range_to_view<T, enable_if_t<!has_const_begin_end<T>::value &&
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has_mutable_begin_end<T>::value>> {
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struct view_t {
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T m_range_copy;
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auto begin() FMT_DECLTYPE_RETURN(detail::range_begin(m_range_copy));
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auto end() FMT_DECLTYPE_RETURN(detail::range_end(m_range_copy));
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};
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static auto view(const T& range) -> view_t { return {range}; }
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};
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# undef FMT_DECLTYPE_RETURN
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#endif
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/// tuple_size and tuple_element check.
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template <typename T> class is_tuple_like_ {
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template <typename U>
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static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
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template <typename> static void check(...);
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public:
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static FMT_CONSTEXPR_DECL const bool value =
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!std::is_void<decltype(check<T>(nullptr))>::value;
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};
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// Check for integer_sequence
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#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
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template <typename T, T... N>
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using integer_sequence = std::integer_sequence<T, N...>;
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template <size_t... N> using index_sequence = std::index_sequence<N...>;
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template <size_t N> using make_index_sequence = std::make_index_sequence<N>;
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#else
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template <typename T, T... N> struct integer_sequence {
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using value_type = T;
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static FMT_CONSTEXPR size_t size() { return sizeof...(N); }
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};
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template <size_t... N> using index_sequence = integer_sequence<size_t, N...>;
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template <typename T, size_t N, T... Ns>
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struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
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template <typename T, T... Ns>
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struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
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template <size_t N>
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using make_index_sequence = make_integer_sequence<size_t, N>;
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#endif
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template <class Tuple, class F, size_t... Is>
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void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT {
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using std::get;
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// using free function get<I>(T) now.
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const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
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(void)_; // blocks warnings
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}
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template <class T>
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FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes(
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T const&) {
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return {};
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}
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template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
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const auto indexes = get_indexes(tup);
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for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
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}
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template <typename Range>
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using value_type =
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remove_cvref_t<decltype(*detail::range_begin(std::declval<Range>()))>;
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template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
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typename std::decay<Arg>::type>::value)>
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FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
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return add_space ? " {}" : "{}";
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}
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template <typename Arg, FMT_ENABLE_IF(is_like_std_string<
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typename std::decay<Arg>::type>::value)>
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FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
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return add_space ? " \"{}\"" : "\"{}\"";
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}
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FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) {
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return add_space ? " \"{}\"" : "\"{}\"";
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}
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FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) {
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return add_space ? L" \"{}\"" : L"\"{}\"";
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}
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FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
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return add_space ? " '{}'" : "'{}'";
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}
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FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
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return add_space ? L" '{}'" : L"'{}'";
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}
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} // namespace detail
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template <typename T> struct is_tuple_like {
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static FMT_CONSTEXPR_DECL const bool value =
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detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
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};
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template <typename TupleT, typename Char>
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struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
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private:
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// C++11 generic lambda for format()
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template <typename FormatContext> struct format_each {
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template <typename T> void operator()(const T& v) {
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if (i > 0) {
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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out = detail::copy(formatting.delimiter, out);
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}
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out = format_to(out,
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detail::format_str_quoted(
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(formatting.add_delimiter_spaces && i > 0), v),
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v);
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++i;
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}
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formatting_tuple<Char>& formatting;
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size_t& i;
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typename std::add_lvalue_reference<decltype(
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std::declval<FormatContext>().out())>::type out;
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};
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public:
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formatting_tuple<Char> formatting;
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
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return formatting.parse(ctx);
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}
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template <typename FormatContext = format_context>
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auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
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auto out = ctx.out();
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size_t i = 0;
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detail::copy(formatting.prefix, out);
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detail::for_each(values, format_each<FormatContext>{formatting, i, out});
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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detail::copy(formatting.postfix, out);
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return ctx.out();
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}
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};
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template <typename T, typename Char> struct is_range {
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static FMT_CONSTEXPR_DECL const bool value =
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detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
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!std::is_convertible<T, std::basic_string<Char>>::value &&
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!std::is_constructible<detail::std_string_view<Char>, T>::value;
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};
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template <typename T, typename Char>
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struct formatter<
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T, Char,
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enable_if_t<fmt::is_range<T, Char>::value
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// Workaround a bug in MSVC 2017 and earlier.
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#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
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&& has_formatter<detail::value_type<T>, format_context>::value
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#endif
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>> {
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formatting_range<Char> formatting;
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
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return formatting.parse(ctx);
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}
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template <typename FormatContext>
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typename FormatContext::iterator format(const T& values, FormatContext& ctx) {
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auto out = detail::copy(formatting.prefix, ctx.out());
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size_t i = 0;
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auto view = detail::range_to_view<T>::view(values);
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auto it = view.begin();
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auto end = view.end();
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for (; it != end; ++it) {
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if (i > 0) {
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if (formatting.add_prepostfix_space) *out++ = ' ';
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out = detail::copy(formatting.delimiter, out);
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}
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out = format_to(out,
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detail::format_str_quoted(
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(formatting.add_delimiter_spaces && i > 0), *it),
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*it);
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if (++i > formatting.range_length_limit) {
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out = format_to(out, " ... <other elements>");
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break;
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}
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}
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if (formatting.add_prepostfix_space) *out++ = ' ';
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return detail::copy(formatting.postfix, out);
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}
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};
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template <typename Char, typename... T> struct tuple_arg_join : detail::view {
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const std::tuple<T...>& tuple;
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basic_string_view<Char> sep;
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tuple_arg_join(const std::tuple<T...>& t, basic_string_view<Char> s)
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: tuple{t}, sep{s} {}
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};
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template <typename Char, typename... T>
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struct formatter<tuple_arg_join<Char, T...>, Char> {
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
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return ctx.begin();
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}
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template <typename FormatContext>
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typename FormatContext::iterator format(
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const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
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return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
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}
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private:
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template <typename FormatContext, size_t... N>
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typename FormatContext::iterator format(
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const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
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detail::index_sequence<N...>) {
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return format_args(value, ctx, std::get<N>(value.tuple)...);
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}
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template <typename FormatContext>
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typename FormatContext::iterator format_args(
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const tuple_arg_join<Char, T...>&, FormatContext& ctx) {
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// NOTE: for compilers that support C++17, this empty function instantiation
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// can be replaced with a constexpr branch in the variadic overload.
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return ctx.out();
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}
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template <typename FormatContext, typename Arg, typename... Args>
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typename FormatContext::iterator format_args(
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const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
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const Arg& arg, const Args&... args) {
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using base = formatter<typename std::decay<Arg>::type, Char>;
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auto out = ctx.out();
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out = base{}.format(arg, ctx);
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if (sizeof...(Args) > 0) {
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out = std::copy(value.sep.begin(), value.sep.end(), out);
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ctx.advance_to(out);
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return format_args(value, ctx, args...);
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}
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return out;
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}
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};
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/**
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\rst
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Returns an object that formats `tuple` with elements separated by `sep`.
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**Example**::
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std::tuple<int, char> t = {1, 'a'};
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fmt::print("{}", fmt::join(t, ", "));
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// Output: "1, a"
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\endrst
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*/
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template <typename... T>
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FMT_CONSTEXPR tuple_arg_join<char, T...> join(const std::tuple<T...>& tuple,
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string_view sep) {
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return {tuple, sep};
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}
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template <typename... T>
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FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
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wstring_view sep) {
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return {tuple, sep};
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}
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/**
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\rst
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Returns an object that formats `initializer_list` with elements separated by
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`sep`.
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**Example**::
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fmt::print("{}", fmt::join({1, 2, 3}, ", "));
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// Output: "1, 2, 3"
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\endrst
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*/
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template <typename T>
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arg_join<const T*, const T*, char> join(std::initializer_list<T> list,
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string_view sep) {
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return join(std::begin(list), std::end(list), sep);
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}
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template <typename T>
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arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list,
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wstring_view sep) {
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return join(std::begin(list), std::end(list), sep);
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}
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FMT_END_NAMESPACE
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#endif // FMT_RANGES_H_
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