Martin Stjernholm | c15e7e4 | 2020-12-02 22:50:53 +0000 | [diff] [blame] | 1 | // Formatting library for C++ - experimental range support |
| 2 | // |
| 3 | // Copyright (c) 2012 - present, Victor Zverovich |
| 4 | // All rights reserved. |
| 5 | // |
| 6 | // For the license information refer to format.h. |
| 7 | // |
| 8 | // Copyright (c) 2018 - present, Remotion (Igor Schulz) |
| 9 | // All Rights Reserved |
| 10 | // {fmt} support for ranges, containers and types tuple interface. |
| 11 | |
| 12 | #ifndef FMT_RANGES_H_ |
| 13 | #define FMT_RANGES_H_ |
| 14 | |
| 15 | #include <initializer_list> |
| 16 | #include <type_traits> |
| 17 | |
| 18 | #include "format.h" |
| 19 | |
| 20 | // output only up to N items from the range. |
| 21 | #ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT |
| 22 | # define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256 |
| 23 | #endif |
| 24 | |
| 25 | FMT_BEGIN_NAMESPACE |
| 26 | |
| 27 | template <typename Char> struct formatting_base { |
| 28 | template <typename ParseContext> |
| 29 | FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { |
| 30 | return ctx.begin(); |
| 31 | } |
| 32 | }; |
| 33 | |
| 34 | template <typename Char, typename Enable = void> |
| 35 | struct formatting_range : formatting_base<Char> { |
| 36 | static FMT_CONSTEXPR_DECL const size_t range_length_limit = |
| 37 | FMT_RANGE_OUTPUT_LENGTH_LIMIT; // output only up to N items from the |
| 38 | // range. |
| 39 | Char prefix; |
| 40 | Char delimiter; |
| 41 | Char postfix; |
| 42 | formatting_range() : prefix('{'), delimiter(','), postfix('}') {} |
| 43 | static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true; |
| 44 | static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false; |
| 45 | }; |
| 46 | |
| 47 | template <typename Char, typename Enable = void> |
| 48 | struct formatting_tuple : formatting_base<Char> { |
| 49 | Char prefix; |
| 50 | Char delimiter; |
| 51 | Char postfix; |
| 52 | formatting_tuple() : prefix('('), delimiter(','), postfix(')') {} |
| 53 | static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true; |
| 54 | static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false; |
| 55 | }; |
| 56 | |
| 57 | namespace detail { |
| 58 | |
| 59 | template <typename RangeT, typename OutputIterator> |
| 60 | OutputIterator copy(const RangeT& range, OutputIterator out) { |
| 61 | for (auto it = range.begin(), end = range.end(); it != end; ++it) |
| 62 | *out++ = *it; |
| 63 | return out; |
| 64 | } |
| 65 | |
| 66 | template <typename OutputIterator> |
| 67 | OutputIterator copy(const char* str, OutputIterator out) { |
| 68 | while (*str) *out++ = *str++; |
| 69 | return out; |
| 70 | } |
| 71 | |
| 72 | template <typename OutputIterator> |
| 73 | OutputIterator copy(char ch, OutputIterator out) { |
| 74 | *out++ = ch; |
| 75 | return out; |
| 76 | } |
| 77 | |
| 78 | /// Return true value if T has std::string interface, like std::string_view. |
| 79 | template <typename T> class is_like_std_string { |
| 80 | template <typename U> |
| 81 | static auto check(U* p) |
| 82 | -> decltype((void)p->find('a'), p->length(), (void)p->data(), int()); |
| 83 | template <typename> static void check(...); |
| 84 | |
| 85 | public: |
| 86 | static FMT_CONSTEXPR_DECL const bool value = |
| 87 | is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value; |
| 88 | }; |
| 89 | |
| 90 | template <typename Char> |
| 91 | struct is_like_std_string<fmt::basic_string_view<Char>> : std::true_type {}; |
| 92 | |
| 93 | template <typename... Ts> struct conditional_helper {}; |
| 94 | |
| 95 | template <typename T, typename _ = void> struct is_range_ : std::false_type {}; |
| 96 | |
| 97 | #if !FMT_MSC_VER || FMT_MSC_VER > 1800 |
| 98 | template <typename T> |
| 99 | struct is_range_< |
| 100 | T, conditional_t<false, |
| 101 | conditional_helper<decltype(std::declval<T>().begin()), |
| 102 | decltype(std::declval<T>().end())>, |
| 103 | void>> : std::true_type {}; |
| 104 | #endif |
| 105 | |
| 106 | /// tuple_size and tuple_element check. |
| 107 | template <typename T> class is_tuple_like_ { |
| 108 | template <typename U> |
| 109 | static auto check(U* p) -> decltype(std::tuple_size<U>::value, int()); |
| 110 | template <typename> static void check(...); |
| 111 | |
| 112 | public: |
| 113 | static FMT_CONSTEXPR_DECL const bool value = |
| 114 | !std::is_void<decltype(check<T>(nullptr))>::value; |
| 115 | }; |
| 116 | |
| 117 | // Check for integer_sequence |
| 118 | #if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900 |
| 119 | template <typename T, T... N> |
| 120 | using integer_sequence = std::integer_sequence<T, N...>; |
| 121 | template <size_t... N> using index_sequence = std::index_sequence<N...>; |
| 122 | template <size_t N> using make_index_sequence = std::make_index_sequence<N>; |
| 123 | #else |
| 124 | template <typename T, T... N> struct integer_sequence { |
| 125 | using value_type = T; |
| 126 | |
| 127 | static FMT_CONSTEXPR size_t size() { return sizeof...(N); } |
| 128 | }; |
| 129 | |
| 130 | template <size_t... N> using index_sequence = integer_sequence<size_t, N...>; |
| 131 | |
| 132 | template <typename T, size_t N, T... Ns> |
| 133 | struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {}; |
| 134 | template <typename T, T... Ns> |
| 135 | struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {}; |
| 136 | |
| 137 | template <size_t N> |
| 138 | using make_index_sequence = make_integer_sequence<size_t, N>; |
| 139 | #endif |
| 140 | |
| 141 | template <class Tuple, class F, size_t... Is> |
| 142 | void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT { |
| 143 | using std::get; |
| 144 | // using free function get<I>(T) now. |
| 145 | const int _[] = {0, ((void)f(get<Is>(tup)), 0)...}; |
| 146 | (void)_; // blocks warnings |
| 147 | } |
| 148 | |
| 149 | template <class T> |
| 150 | FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes( |
| 151 | T const&) { |
| 152 | return {}; |
| 153 | } |
| 154 | |
| 155 | template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) { |
| 156 | const auto indexes = get_indexes(tup); |
| 157 | for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f)); |
| 158 | } |
| 159 | |
| 160 | template <typename Range> |
| 161 | using value_type = remove_cvref_t<decltype(*std::declval<Range>().begin())>; |
| 162 | |
| 163 | template <typename Arg, FMT_ENABLE_IF(!is_like_std_string< |
| 164 | typename std::decay<Arg>::type>::value)> |
| 165 | FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) { |
| 166 | return add_space ? " {}" : "{}"; |
| 167 | } |
| 168 | |
| 169 | template <typename Arg, FMT_ENABLE_IF(is_like_std_string< |
| 170 | typename std::decay<Arg>::type>::value)> |
| 171 | FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) { |
| 172 | return add_space ? " \"{}\"" : "\"{}\""; |
| 173 | } |
| 174 | |
| 175 | FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) { |
| 176 | return add_space ? " \"{}\"" : "\"{}\""; |
| 177 | } |
| 178 | FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) { |
| 179 | return add_space ? L" \"{}\"" : L"\"{}\""; |
| 180 | } |
| 181 | |
| 182 | FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) { |
| 183 | return add_space ? " '{}'" : "'{}'"; |
| 184 | } |
| 185 | FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) { |
| 186 | return add_space ? L" '{}'" : L"'{}'"; |
| 187 | } |
| 188 | } // namespace detail |
| 189 | |
| 190 | template <typename T> struct is_tuple_like { |
| 191 | static FMT_CONSTEXPR_DECL const bool value = |
| 192 | detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value; |
| 193 | }; |
| 194 | |
| 195 | template <typename TupleT, typename Char> |
| 196 | struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> { |
| 197 | private: |
| 198 | // C++11 generic lambda for format() |
| 199 | template <typename FormatContext> struct format_each { |
| 200 | template <typename T> void operator()(const T& v) { |
| 201 | if (i > 0) { |
| 202 | if (formatting.add_prepostfix_space) { |
| 203 | *out++ = ' '; |
| 204 | } |
| 205 | out = detail::copy(formatting.delimiter, out); |
| 206 | } |
| 207 | out = format_to(out, |
| 208 | detail::format_str_quoted( |
| 209 | (formatting.add_delimiter_spaces && i > 0), v), |
| 210 | v); |
| 211 | ++i; |
| 212 | } |
| 213 | |
| 214 | formatting_tuple<Char>& formatting; |
| 215 | size_t& i; |
| 216 | typename std::add_lvalue_reference<decltype( |
| 217 | std::declval<FormatContext>().out())>::type out; |
| 218 | }; |
| 219 | |
| 220 | public: |
| 221 | formatting_tuple<Char> formatting; |
| 222 | |
| 223 | template <typename ParseContext> |
| 224 | FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { |
| 225 | return formatting.parse(ctx); |
| 226 | } |
| 227 | |
| 228 | template <typename FormatContext = format_context> |
| 229 | auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) { |
| 230 | auto out = ctx.out(); |
| 231 | size_t i = 0; |
| 232 | detail::copy(formatting.prefix, out); |
| 233 | |
| 234 | detail::for_each(values, format_each<FormatContext>{formatting, i, out}); |
| 235 | if (formatting.add_prepostfix_space) { |
| 236 | *out++ = ' '; |
| 237 | } |
| 238 | detail::copy(formatting.postfix, out); |
| 239 | |
| 240 | return ctx.out(); |
| 241 | } |
| 242 | }; |
| 243 | |
| 244 | template <typename T, typename Char> struct is_range { |
| 245 | static FMT_CONSTEXPR_DECL const bool value = |
| 246 | detail::is_range_<T>::value && !detail::is_like_std_string<T>::value && |
| 247 | !std::is_convertible<T, std::basic_string<Char>>::value && |
| 248 | !std::is_constructible<detail::std_string_view<Char>, T>::value; |
| 249 | }; |
| 250 | |
| 251 | template <typename T, typename Char> |
| 252 | struct formatter< |
| 253 | T, Char, |
| 254 | enable_if_t<fmt::is_range<T, Char>::value |
| 255 | // Workaround a bug in MSVC 2017 and earlier. |
| 256 | #if !FMT_MSC_VER || FMT_MSC_VER >= 1927 |
| 257 | && |
| 258 | (has_formatter<detail::value_type<T>, format_context>::value || |
| 259 | detail::has_fallback_formatter<detail::value_type<T>, |
| 260 | format_context>::value) |
| 261 | #endif |
| 262 | >> { |
| 263 | formatting_range<Char> formatting; |
| 264 | |
| 265 | template <typename ParseContext> |
| 266 | FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { |
| 267 | return formatting.parse(ctx); |
| 268 | } |
| 269 | |
| 270 | template <typename FormatContext> |
| 271 | typename FormatContext::iterator format(const T& values, FormatContext& ctx) { |
| 272 | auto out = detail::copy(formatting.prefix, ctx.out()); |
| 273 | size_t i = 0; |
| 274 | auto it = values.begin(); |
| 275 | auto end = values.end(); |
| 276 | for (; it != end; ++it) { |
| 277 | if (i > 0) { |
| 278 | if (formatting.add_prepostfix_space) *out++ = ' '; |
| 279 | out = detail::copy(formatting.delimiter, out); |
| 280 | } |
| 281 | out = format_to(out, |
| 282 | detail::format_str_quoted( |
| 283 | (formatting.add_delimiter_spaces && i > 0), *it), |
| 284 | *it); |
| 285 | if (++i > formatting.range_length_limit) { |
| 286 | out = format_to(out, " ... <other elements>"); |
| 287 | break; |
| 288 | } |
| 289 | } |
| 290 | if (formatting.add_prepostfix_space) *out++ = ' '; |
| 291 | return detail::copy(formatting.postfix, out); |
| 292 | } |
| 293 | }; |
| 294 | |
| 295 | template <typename Char, typename... T> struct tuple_arg_join : detail::view { |
| 296 | const std::tuple<T...>& tuple; |
| 297 | basic_string_view<Char> sep; |
| 298 | |
| 299 | tuple_arg_join(const std::tuple<T...>& t, basic_string_view<Char> s) |
| 300 | : tuple{t}, sep{s} {} |
| 301 | }; |
| 302 | |
| 303 | template <typename Char, typename... T> |
| 304 | struct formatter<tuple_arg_join<Char, T...>, Char> { |
| 305 | template <typename ParseContext> |
| 306 | FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { |
| 307 | return ctx.begin(); |
| 308 | } |
| 309 | |
| 310 | template <typename FormatContext> |
| 311 | typename FormatContext::iterator format( |
| 312 | const tuple_arg_join<Char, T...>& value, FormatContext& ctx) { |
| 313 | return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{}); |
| 314 | } |
| 315 | |
| 316 | private: |
| 317 | template <typename FormatContext, size_t... N> |
| 318 | typename FormatContext::iterator format( |
| 319 | const tuple_arg_join<Char, T...>& value, FormatContext& ctx, |
| 320 | detail::index_sequence<N...>) { |
| 321 | return format_args(value, ctx, std::get<N>(value.tuple)...); |
| 322 | } |
| 323 | |
| 324 | template <typename FormatContext> |
| 325 | typename FormatContext::iterator format_args( |
| 326 | const tuple_arg_join<Char, T...>&, FormatContext& ctx) { |
| 327 | // NOTE: for compilers that support C++17, this empty function instantiation |
| 328 | // can be replaced with a constexpr branch in the variadic overload. |
| 329 | return ctx.out(); |
| 330 | } |
| 331 | |
| 332 | template <typename FormatContext, typename Arg, typename... Args> |
| 333 | typename FormatContext::iterator format_args( |
| 334 | const tuple_arg_join<Char, T...>& value, FormatContext& ctx, |
| 335 | const Arg& arg, const Args&... args) { |
| 336 | using base = formatter<typename std::decay<Arg>::type, Char>; |
| 337 | auto out = ctx.out(); |
| 338 | out = base{}.format(arg, ctx); |
| 339 | if (sizeof...(Args) > 0) { |
| 340 | out = std::copy(value.sep.begin(), value.sep.end(), out); |
| 341 | ctx.advance_to(out); |
| 342 | return format_args(value, ctx, args...); |
| 343 | } |
| 344 | return out; |
| 345 | } |
| 346 | }; |
| 347 | |
| 348 | /** |
| 349 | \rst |
| 350 | Returns an object that formats `tuple` with elements separated by `sep`. |
| 351 | |
| 352 | **Example**:: |
| 353 | |
| 354 | std::tuple<int, char> t = {1, 'a'}; |
| 355 | fmt::print("{}", fmt::join(t, ", ")); |
| 356 | // Output: "1, a" |
| 357 | \endrst |
| 358 | */ |
| 359 | template <typename... T> |
| 360 | FMT_CONSTEXPR tuple_arg_join<char, T...> join(const std::tuple<T...>& tuple, |
| 361 | string_view sep) { |
| 362 | return {tuple, sep}; |
| 363 | } |
| 364 | |
| 365 | template <typename... T> |
| 366 | FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple, |
| 367 | wstring_view sep) { |
| 368 | return {tuple, sep}; |
| 369 | } |
| 370 | |
| 371 | /** |
| 372 | \rst |
| 373 | Returns an object that formats `initializer_list` with elements separated by |
| 374 | `sep`. |
| 375 | |
| 376 | **Example**:: |
| 377 | |
| 378 | fmt::print("{}", fmt::join({1, 2, 3}, ", ")); |
| 379 | // Output: "1, 2, 3" |
| 380 | \endrst |
| 381 | */ |
| 382 | template <typename T> |
| 383 | arg_join<const T*, const T*, char> join(std::initializer_list<T> list, |
| 384 | string_view sep) { |
| 385 | return join(std::begin(list), std::end(list), sep); |
| 386 | } |
| 387 | |
| 388 | template <typename T> |
| 389 | arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list, |
| 390 | wstring_view sep) { |
| 391 | return join(std::begin(list), std::end(list), sep); |
| 392 | } |
| 393 | |
| 394 | FMT_END_NAMESPACE |
| 395 | |
| 396 | #endif // FMT_RANGES_H_ |