src/cpp-common/vendor/fmt/compile.h

   1 // Formatting library for C++ - experimental format string compilation
   2 //
   3 // Copyright (c) 2012 - present, Victor Zverovich and fmt contributors
   4 // All rights reserved.
   5 //
   6 // For the license information refer to format.h.
   7
   8 #ifndef FMT_COMPILE_H_
   9 #define FMT_COMPILE_H_
  10
  11 #include "format.h"
  12
  13 FMT_BEGIN_NAMESPACE
  14 namespace detail {
  15
  16 template <typename Char, typename InputIt>
  17 FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
  18                                                 counting_iterator it) {
  19   return it + (end - begin);
  20 }
  21
  22 // A compile-time string which is compiled into fast formatting code.
  23 class compiled_string {};
  24
  25 template <typename S>
  26 struct is_compiled_string : std::is_base_of<compiled_string, S> {};
  27
  28 /**
  29   \rst
  30   Converts a string literal *s* into a format string that will be parsed at
  31   compile time and converted into efficient formatting code. Requires C++17
  32   ``constexpr if`` compiler support.
  33
  34   **Example**::
  35
  36     // Converts 42 into std::string using the most efficient method and no
  37     // runtime format string processing.
  38     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
  39   \endrst
  40  */
  41 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
  42 #  define FMT_COMPILE(s) \
  43     FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
  44 #else
  45 #  define FMT_COMPILE(s) FMT_STRING(s)
  46 #endif
  47
  48 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
  49 template <typename Char, size_t N,
  50           fmt::detail_exported::fixed_string<Char, N> Str>
  51 struct udl_compiled_string : compiled_string {
  52   using char_type = Char;
  53   explicit constexpr operator basic_string_view<char_type>() const {
  54     return {Str.data, N - 1};
  55   }
  56 };
  57 #endif
  58
  59 template <typename T, typename... Tail>
  60 const T& first(const T& value, const Tail&...) {
  61   return value;
  62 }
  63
  64 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
  65 template <typename... Args> struct type_list {};
  66
  67 // Returns a reference to the argument at index N from [first, rest...].
  68 template <int N, typename T, typename... Args>
  69 constexpr const auto& get([[maybe_unused]] const T& first,
  70                           [[maybe_unused]] const Args&... rest) {
  71   static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
  72   if constexpr (N == 0)
  73     return first;
  74   else
  75     return detail::get<N - 1>(rest...);
  76 }
  77
  78 template <typename Char, typename... Args>
  79 constexpr int get_arg_index_by_name(basic_string_view<Char> name,
  80                                     type_list<Args...>) {
  81   return get_arg_index_by_name<Args...>(name);
  82 }
  83
  84 template <int N, typename> struct get_type_impl;
  85
  86 template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
  87   using type =
  88       remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
  89 };
  90
  91 template <int N, typename T>
  92 using get_type = typename get_type_impl<N, T>::type;
  93
  94 template <typename T> struct is_compiled_format : std::false_type {};
  95
  96 template <typename Char> struct text {
  97   basic_string_view<Char> data;
  98   using char_type = Char;
  99
 100   template <typename OutputIt, typename... Args>
 101   constexpr OutputIt format(OutputIt out, const Args&...) const {
 102     return write<Char>(out, data);
 103   }
 104 };
 105
 106 template <typename Char>
 107 struct is_compiled_format<text<Char>> : std::true_type {};
 108
 109 template <typename Char>
 110 constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
 111                                size_t size) {
 112   return {{&s[pos], size}};
 113 }
 114
 115 template <typename Char> struct code_unit {
 116   Char value;
 117   using char_type = Char;
 118
 119   template <typename OutputIt, typename... Args>
 120   constexpr OutputIt format(OutputIt out, const Args&...) const {
 121     *out++ = value;
 122     return out;
 123   }
 124 };
 125
 126 // This ensures that the argument type is convertible to `const T&`.
 127 template <typename T, int N, typename... Args>
 128 constexpr const T& get_arg_checked(const Args&... args) {
 129   const auto& arg = detail::get<N>(args...);
 130   if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
 131     return arg.value;
 132   } else {
 133     return arg;
 134   }
 135 }
 136
 137 template <typename Char>
 138 struct is_compiled_format<code_unit<Char>> : std::true_type {};
 139
 140 // A replacement field that refers to argument N.
 141 template <typename Char, typename T, int N> struct field {
 142   using char_type = Char;
 143
 144   template <typename OutputIt, typename... Args>
 145   constexpr OutputIt format(OutputIt out, const Args&... args) const {
 146     const T& arg = get_arg_checked<T, N>(args...);
 147     if constexpr (std::is_convertible_v<T, basic_string_view<Char>>) {
 148       auto s = basic_string_view<Char>(arg);
 149       return copy_str<Char>(s.begin(), s.end(), out);
 150     }
 151     return write<Char>(out, arg);
 152   }
 153 };
 154
 155 template <typename Char, typename T, int N>
 156 struct is_compiled_format<field<Char, T, N>> : std::true_type {};
 157
 158 // A replacement field that refers to argument with name.
 159 template <typename Char> struct runtime_named_field {
 160   using char_type = Char;
 161   basic_string_view<Char> name;
 162
 163   template <typename OutputIt, typename T>
 164   constexpr static bool try_format_argument(
 165       OutputIt& out,
 166       // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
 167       [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
 168     if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
 169       if (arg_name == arg.name) {
 170         out = write<Char>(out, arg.value);
 171         return true;
 172       }
 173     }
 174     return false;
 175   }
 176
 177   template <typename OutputIt, typename... Args>
 178   constexpr OutputIt format(OutputIt out, const Args&... args) const {
 179     bool found = (try_format_argument(out, name, args) || ...);
 180     if (!found) {
 181       FMT_THROW(format_error("argument with specified name is not found"));
 182     }
 183     return out;
 184   }
 185 };
 186
 187 template <typename Char>
 188 struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};
 189
 190 // A replacement field that refers to argument N and has format specifiers.
 191 template <typename Char, typename T, int N> struct spec_field {
 192   using char_type = Char;
 193   formatter<T, Char> fmt;
 194
 195   template <typename OutputIt, typename... Args>
 196   constexpr FMT_INLINE OutputIt format(OutputIt out,
 197                                        const Args&... args) const {
 198     const auto& vargs =
 199         fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
 200     basic_format_context<OutputIt, Char> ctx(out, vargs);
 201     return fmt.format(get_arg_checked<T, N>(args...), ctx);
 202   }
 203 };
 204
 205 template <typename Char, typename T, int N>
 206 struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};
 207
 208 template <typename L, typename R> struct concat {
 209   L lhs;
 210   R rhs;
 211   using char_type = typename L::char_type;
 212
 213   template <typename OutputIt, typename... Args>
 214   constexpr OutputIt format(OutputIt out, const Args&... args) const {
 215     out = lhs.format(out, args...);
 216     return rhs.format(out, args...);
 217   }
 218 };
 219
 220 template <typename L, typename R>
 221 struct is_compiled_format<concat<L, R>> : std::true_type {};
 222
 223 template <typename L, typename R>
 224 constexpr concat<L, R> make_concat(L lhs, R rhs) {
 225   return {lhs, rhs};
 226 }
 227
 228 struct unknown_format {};
 229
 230 template <typename Char>
 231 constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
 232   for (size_t size = str.size(); pos != size; ++pos) {
 233     if (str[pos] == '{' || str[pos] == '}') break;
 234   }
 235   return pos;
 236 }
 237
 238 template <typename Args, size_t POS, int ID, typename S>
 239 constexpr auto compile_format_string(S format_str);
 240
 241 template <typename Args, size_t POS, int ID, typename T, typename S>
 242 constexpr auto parse_tail(T head, S format_str) {
 243   if constexpr (POS !=
 244                 basic_string_view<typename S::char_type>(format_str).size()) {
 245     constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
 246     if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
 247                                unknown_format>())
 248       return tail;
 249     else
 250       return make_concat(head, tail);
 251   } else {
 252     return head;
 253   }
 254 }
 255
 256 template <typename T, typename Char> struct parse_specs_result {
 257   formatter<T, Char> fmt;
 258   size_t end;
 259   int next_arg_id;
 260 };
 261
 262 enum { manual_indexing_id = -1 };
 263
 264 template <typename T, typename Char>
 265 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 266                                                   size_t pos, int next_arg_id) {
 267   str.remove_prefix(pos);
 268   auto ctx =
 269       compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
 270   auto f = formatter<T, Char>();
 271   auto end = f.parse(ctx);
 272   return {f, pos + fmt::detail::to_unsigned(end - str.data()),
 273           next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
 274 }
 275
 276 template <typename Char> struct arg_id_handler {
 277   arg_ref<Char> arg_id;
 278
 279   constexpr int on_auto() {
 280     FMT_ASSERT(false, "handler cannot be used with automatic indexing");
 281     return 0;
 282   }
 283   constexpr int on_index(int id) {
 284     arg_id = arg_ref<Char>(id);
 285     return 0;
 286   }
 287   constexpr int on_name(basic_string_view<Char> id) {
 288     arg_id = arg_ref<Char>(id);
 289     return 0;
 290   }
 291 };
 292
 293 template <typename Char> struct parse_arg_id_result {
 294   arg_ref<Char> arg_id;
 295   const Char* arg_id_end;
 296 };
 297
 298 template <int ID, typename Char>
 299 constexpr auto parse_arg_id(const Char* begin, const Char* end) {
 300   auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
 301   auto arg_id_end = parse_arg_id(begin, end, handler);
 302   return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
 303 }
 304
 305 template <typename T, typename Enable = void> struct field_type {
 306   using type = remove_cvref_t<T>;
 307 };
 308
 309 template <typename T>
 310 struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
 311   using type = remove_cvref_t<decltype(T::value)>;
 312 };
 313
 314 template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
 315           typename S>
 316 constexpr auto parse_replacement_field_then_tail(S format_str) {
 317   using char_type = typename S::char_type;
 318   constexpr auto str = basic_string_view<char_type>(format_str);
 319   constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
 320   if constexpr (c == '}') {
 321     return parse_tail<Args, END_POS + 1, NEXT_ID>(
 322         field<char_type, typename field_type<T>::type, ARG_INDEX>(),
 323         format_str);
 324   } else if constexpr (c != ':') {
 325     FMT_THROW(format_error("expected ':'"));
 326   } else {
 327     constexpr auto result = parse_specs<typename field_type<T>::type>(
 328         str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
 329     if constexpr (result.end >= str.size() || str[result.end] != '}') {
 330       FMT_THROW(format_error("expected '}'"));
 331       return 0;
 332     } else {
 333       return parse_tail<Args, result.end + 1, result.next_arg_id>(
 334           spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
 335               result.fmt},
 336           format_str);
 337     }
 338   }
 339 }
 340
 341 // Compiles a non-empty format string and returns the compiled representation
 342 // or unknown_format() on unrecognized input.
 343 template <typename Args, size_t POS, int ID, typename S>
 344 constexpr auto compile_format_string(S format_str) {
 345   using char_type = typename S::char_type;
 346   constexpr auto str = basic_string_view<char_type>(format_str);
 347   if constexpr (str[POS] == '{') {
 348     if constexpr (POS + 1 == str.size())
 349       FMT_THROW(format_error("unmatched '{' in format string"));
 350     if constexpr (str[POS + 1] == '{') {
 351       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
 352     } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
 353       static_assert(ID != manual_indexing_id,
 354                     "cannot switch from manual to automatic argument indexing");
 355       constexpr auto next_id =
 356           ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
 357       return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
 358                                                POS + 1, ID, next_id>(
 359           format_str);
 360     } else {
 361       constexpr auto arg_id_result =
 362           parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
 363       constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
 364       constexpr char_type c =
 365           arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
 366       static_assert(c == '}' || c == ':', "missing '}' in format string");
 367       if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
 368         static_assert(
 369             ID == manual_indexing_id || ID == 0,
 370             "cannot switch from automatic to manual argument indexing");
 371         constexpr auto arg_index = arg_id_result.arg_id.val.index;
 372         return parse_replacement_field_then_tail<get_type<arg_index, Args>,
 373                                                  Args, arg_id_end_pos,
 374                                                  arg_index, manual_indexing_id>(
 375             format_str);
 376       } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
 377         constexpr auto arg_index =
 378             get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
 379         if constexpr (arg_index >= 0) {
 380           constexpr auto next_id =
 381               ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
 382           return parse_replacement_field_then_tail<
 383               decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
 384               arg_index, next_id>(format_str);
 385         } else if constexpr (c == '}') {
 386           return parse_tail<Args, arg_id_end_pos + 1, ID>(
 387               runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
 388               format_str);
 389         } else if constexpr (c == ':') {
 390           return unknown_format();  // no type info for specs parsing
 391         }
 392       }
 393     }
 394   } else if constexpr (str[POS] == '}') {
 395     if constexpr (POS + 1 == str.size())
 396       FMT_THROW(format_error("unmatched '}' in format string"));
 397     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
 398   } else {
 399     constexpr auto end = parse_text(str, POS + 1);
 400     if constexpr (end - POS > 1) {
 401       return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
 402                                        format_str);
 403     } else {
 404       return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
 405                                        format_str);
 406     }
 407   }
 408 }
 409
 410 template <typename... Args, typename S,
 411           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 412 constexpr auto compile(S format_str) {
 413   constexpr auto str = basic_string_view<typename S::char_type>(format_str);
 414   if constexpr (str.size() == 0) {
 415     return detail::make_text(str, 0, 0);
 416   } else {
 417     constexpr auto result =
 418         detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
 419             format_str);
 420     return result;
 421   }
 422 }
 423 #endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 424 }  // namespace detail
 425
 426 FMT_BEGIN_EXPORT
 427
 428 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 429
 430 template <typename CompiledFormat, typename... Args,
 431           typename Char = typename CompiledFormat::char_type,
 432           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 433 FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
 434                                           const Args&... args) {
 435   auto s = std::basic_string<Char>();
 436   cf.format(std::back_inserter(s), args...);
 437   return s;
 438 }
 439
 440 template <typename OutputIt, typename CompiledFormat, typename... Args,
 441           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 442 constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
 443                                         const Args&... args) {
 444   return cf.format(out, args...);
 445 }
 446
 447 template <typename S, typename... Args,
 448           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 449 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
 450                                                            Args&&... args) {
 451   if constexpr (std::is_same<typename S::char_type, char>::value) {
 452     constexpr auto str = basic_string_view<typename S::char_type>(S());
 453     if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
 454       const auto& first = detail::first(args...);
 455       if constexpr (detail::is_named_arg<
 456                         remove_cvref_t<decltype(first)>>::value) {
 457         return fmt::to_string(first.value);
 458       } else {
 459         return fmt::to_string(first);
 460       }
 461     }
 462   }
 463   constexpr auto compiled = detail::compile<Args...>(S());
 464   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
 465                              detail::unknown_format>()) {
 466     return fmt::format(
 467         static_cast<basic_string_view<typename S::char_type>>(S()),
 468         std::forward<Args>(args)...);
 469   } else {
 470     return fmt::format(compiled, std::forward<Args>(args)...);
 471   }
 472 }
 473
 474 template <typename OutputIt, typename S, typename... Args,
 475           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 476 FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
 477   constexpr auto compiled = detail::compile<Args...>(S());
 478   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
 479                              detail::unknown_format>()) {
 480     return fmt::format_to(
 481         out, static_cast<basic_string_view<typename S::char_type>>(S()),
 482         std::forward<Args>(args)...);
 483   } else {
 484     return fmt::format_to(out, compiled, std::forward<Args>(args)...);
 485   }
 486 }
 487 #endif
 488
 489 template <typename OutputIt, typename S, typename... Args,
 490           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 491 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
 492                                          const S& format_str, Args&&... args) {
 493   using traits = detail::fixed_buffer_traits;
 494   auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
 495   format_to(std::back_inserter(buf), format_str, std::forward<Args>(args)...);
 496   return {buf.out(), buf.count()};
 497 }
 498
 499 template <typename S, typename... Args,
 500           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 501 FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
 502                                       const Args&... args) {
 503   return fmt::format_to(detail::counting_iterator(), format_str, args...)
 504       .count();
 505 }
 506
 507 template <typename S, typename... Args,
 508           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 509 void print(std::FILE* f, const S& format_str, const Args&... args) {
 510   memory_buffer buffer;
 511   fmt::format_to(std::back_inserter(buffer), format_str, args...);
 512   detail::print(f, {buffer.data(), buffer.size()});
 513 }
 514
 515 template <typename S, typename... Args,
 516           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 517 void print(const S& format_str, const Args&... args) {
 518   print(stdout, format_str, args...);
 519 }
 520
 521 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 522 inline namespace literals {
 523 template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
 524   using char_t = remove_cvref_t<decltype(Str.data[0])>;
 525   return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
 526                                      Str>();
 527 }
 528 }  // namespace literals
 529 #endif
 530
 531 FMT_END_EXPORT
 532 FMT_END_NAMESPACE
 533
 534 #endif  // FMT_COMPILE_H_