// Formatting library for C++ - experimental range support // // Copyright (c) 2012 - present, Victor Zverovich // All rights reserved. // // For the license information refer to format.h. // // Copyright (c) 2018 - present, Remotion (Igor Schulz) // All Rights Reserved // {fmt} support for ranges, containers and types tuple interface. #ifndef FMT_RANGES_H_ #define FMT_RANGES_H_ #include #include "format.h" // output only up to N items from the range. #ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT # define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256 #endif FMT_BEGIN_NAMESPACE template struct formatting_base { template FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { return ctx.begin(); } }; template struct formatting_range : formatting_base { static FMT_CONSTEXPR_DECL const std::size_t range_length_limit = FMT_RANGE_OUTPUT_LENGTH_LIMIT; // output only up to N items from the // range. Char prefix; Char delimiter; Char postfix; formatting_range() : prefix('{'), delimiter(','), postfix('}') {} static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true; static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false; }; template struct formatting_tuple : formatting_base { Char prefix; Char delimiter; Char postfix; formatting_tuple() : prefix('('), delimiter(','), postfix(')') {} static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true; static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false; }; namespace internal { template OutputIterator copy(const RangeT& range, OutputIterator out) { for (auto it = range.begin(), end = range.end(); it != end; ++it) *out++ = *it; return out; } template OutputIterator copy(const char* str, OutputIterator out) { while (*str) *out++ = *str++; return out; } template OutputIterator copy(char ch, OutputIterator out) { *out++ = ch; return out; } /// Return true value if T has std::string interface, like std::string_view. template class is_like_std_string { template static auto check(U* p) -> decltype((void)p->find('a'), p->length(), (void)p->data(), int()); template static void check(...); public: static FMT_CONSTEXPR_DECL const bool value = is_string::value || !std::is_void(nullptr))>::value; }; template struct is_like_std_string> : std::true_type {}; template struct conditional_helper {}; template struct is_range_ : std::false_type {}; #if !FMT_MSC_VER || FMT_MSC_VER > 1800 template struct is_range_< T, conditional_t().begin()), decltype(std::declval().end())>, void>> : std::true_type {}; #endif /// tuple_size and tuple_element check. template class is_tuple_like_ { template static auto check(U* p) -> decltype(std::tuple_size::value, (void)std::declval::type>(), int()); template static void check(...); public: static FMT_CONSTEXPR_DECL const bool value = !std::is_void(nullptr))>::value; }; // Check for integer_sequence #if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900 template using integer_sequence = std::integer_sequence; template using index_sequence = std::index_sequence; template using make_index_sequence = std::make_index_sequence; #else template struct integer_sequence { using value_type = T; static FMT_CONSTEXPR std::size_t size() { return sizeof...(N); } }; template using index_sequence = integer_sequence; template struct make_integer_sequence : make_integer_sequence {}; template struct make_integer_sequence : integer_sequence {}; template using make_index_sequence = make_integer_sequence; #endif template void for_each(index_sequence, Tuple&& tup, F&& f) FMT_NOEXCEPT { using std::get; // using free function get(T) now. const int _[] = {0, ((void)f(get(tup)), 0)...}; (void)_; // blocks warnings } template FMT_CONSTEXPR make_index_sequence::value> get_indexes( T const&) { return {}; } template void for_each(Tuple&& tup, F&& f) { const auto indexes = get_indexes(tup); for_each(indexes, std::forward(tup), std::forward(f)); } template ::type>::value)> FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) { return add_space ? " {}" : "{}"; } template ::type>::value)> FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) { return add_space ? " \"{}\"" : "\"{}\""; } FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) { return add_space ? " \"{}\"" : "\"{}\""; } FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) { return add_space ? L" \"{}\"" : L"\"{}\""; } FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) { return add_space ? " '{}'" : "'{}'"; } FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) { return add_space ? L" '{}'" : L"'{}'"; } } // namespace internal template struct is_tuple_like { static FMT_CONSTEXPR_DECL const bool value = internal::is_tuple_like_::value && !internal::is_range_::value; }; template struct formatter::value>> { private: // C++11 generic lambda for format() template struct format_each { template void operator()(const T& v) { if (i > 0) { if (formatting.add_prepostfix_space) { *out++ = ' '; } out = internal::copy(formatting.delimiter, out); } out = format_to(out, internal::format_str_quoted( (formatting.add_delimiter_spaces && i > 0), v), v); ++i; } formatting_tuple& formatting; std::size_t& i; typename std::add_lvalue_reference().out())>::type out; }; public: formatting_tuple formatting; template FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { return formatting.parse(ctx); } template auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) { auto out = ctx.out(); std::size_t i = 0; internal::copy(formatting.prefix, out); internal::for_each(values, format_each{formatting, i, out}); if (formatting.add_prepostfix_space) { *out++ = ' '; } internal::copy(formatting.postfix, out); return ctx.out(); } }; template struct is_range { static FMT_CONSTEXPR_DECL const bool value = internal::is_range_::value && !internal::is_like_std_string::value && !std::is_convertible>::value && !std::is_constructible, T>::value; }; template struct formatter::value>> { formatting_range formatting; template FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { return formatting.parse(ctx); } template typename FormatContext::iterator format(const RangeT& values, FormatContext& ctx) { auto out = internal::copy(formatting.prefix, ctx.out()); std::size_t i = 0; for (auto it = values.begin(), end = values.end(); it != end; ++it) { if (i > 0) { if (formatting.add_prepostfix_space) *out++ = ' '; out = internal::copy(formatting.delimiter, out); } out = format_to(out, internal::format_str_quoted( (formatting.add_delimiter_spaces && i > 0), *it), *it); if (++i > formatting.range_length_limit) { out = format_to(out, " ... "); break; } } if (formatting.add_prepostfix_space) *out++ = ' '; return internal::copy(formatting.postfix, out); } }; template struct tuple_arg_join : internal::view { const std::tuple& tuple; basic_string_view sep; tuple_arg_join(const std::tuple& t, basic_string_view s) : tuple{t}, sep{s} {} }; template struct formatter, Char> { template FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { return ctx.begin(); } template typename FormatContext::iterator format( const tuple_arg_join& value, FormatContext& ctx) { return format(value, ctx, internal::make_index_sequence{}); } private: template typename FormatContext::iterator format( const tuple_arg_join& value, FormatContext& ctx, internal::index_sequence) { return format_args(value, ctx, std::get(value.tuple)...); } template typename FormatContext::iterator format_args( const tuple_arg_join&, FormatContext& ctx) { // NOTE: for compilers that support C++17, this empty function instantiation // can be replaced with a constexpr branch in the variadic overload. return ctx.out(); } template typename FormatContext::iterator format_args( const tuple_arg_join& value, FormatContext& ctx, const Arg& arg, const Args&... args) { using base = formatter::type, Char>; auto out = ctx.out(); out = base{}.format(arg, ctx); if (sizeof...(Args) > 0) { out = std::copy(value.sep.begin(), value.sep.end(), out); ctx.advance_to(out); return format_args(value, ctx, args...); } return out; } }; /** \rst Returns an object that formats `tuple` with elements separated by `sep`. **Example**:: std::tuple t = {1, 'a'}; fmt::print("{}", fmt::join(t, ", ")); // Output: "1, a" \endrst */ template FMT_CONSTEXPR tuple_arg_join join(const std::tuple& tuple, string_view sep) { return {tuple, sep}; } template FMT_CONSTEXPR tuple_arg_join join(const std::tuple& tuple, wstring_view sep) { return {tuple, sep}; } FMT_END_NAMESPACE #endif // FMT_RANGES_H_