substitute.h (35718B)
1 // 2 // Copyright 2017 The Abseil Authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // https://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 // ----------------------------------------------------------------------------- 17 // File: substitute.h 18 // ----------------------------------------------------------------------------- 19 // 20 // This package contains functions for efficiently performing string 21 // substitutions using a format string with positional notation: 22 // `Substitute()` and `SubstituteAndAppend()`. 23 // 24 // Unlike printf-style format specifiers, `Substitute()` functions do not need 25 // to specify the type of the substitution arguments. Supported arguments 26 // following the format string, such as strings, string_views, ints, 27 // floats, and bools, are automatically converted to strings during the 28 // substitution process. (See below for a full list of supported types.) 29 // 30 // `Substitute()` does not allow you to specify *how* to format a value, beyond 31 // the default conversion to string. For example, you cannot format an integer 32 // in hex. 33 // 34 // The format string uses positional identifiers indicated by a dollar sign ($) 35 // and single digit positional ids to indicate which substitution arguments to 36 // use at that location within the format string. 37 // 38 // A '$$' sequence in the format string causes a literal '$' character to be 39 // output. 40 // 41 // Example 1: 42 // std::string s = Substitute("$1 purchased $0 $2 for $$10. Thanks $1!", 43 // 5, "Bob", "Apples"); 44 // EXPECT_EQ("Bob purchased 5 Apples for $10. Thanks Bob!", s); 45 // 46 // Example 2: 47 // std::string s = "Hi. "; 48 // SubstituteAndAppend(&s, "My name is $0 and I am $1 years old.", "Bob", 5); 49 // EXPECT_EQ("Hi. My name is Bob and I am 5 years old.", s); 50 // 51 // Supported types: 52 // * absl::string_view, std::string, const char* (null is equivalent to "") 53 // * int32_t, int64_t, uint32_t, uint64_t 54 // * float, double 55 // * bool (Printed as "true" or "false") 56 // * pointer types other than char* (Printed as "0x<lower case hex string>", 57 // except that null is printed as "NULL") 58 // * user-defined types via the `AbslStringify()` customization point. See the 59 // documentation for `absl::StrCat` for an explanation on how to use this. 60 // 61 // If an invalid format string is provided, Substitute returns an empty string 62 // and SubstituteAndAppend does not change the provided output string. 63 // A format string is invalid if it: 64 // * ends in an unescaped $ character, 65 // e.g. "Hello $", or 66 // * calls for a position argument which is not provided, 67 // e.g. Substitute("Hello $2", "world"), or 68 // * specifies a non-digit, non-$ character after an unescaped $ character, 69 // e.g. "Hello $f". 70 // In debug mode, i.e. #ifndef NDEBUG, such errors terminate the program. 71 72 #ifndef ABSL_STRINGS_SUBSTITUTE_H_ 73 #define ABSL_STRINGS_SUBSTITUTE_H_ 74 75 #include <cstring> 76 #include <string> 77 #include <type_traits> 78 #include <vector> 79 80 #include "absl/base/macros.h" 81 #include "absl/base/nullability.h" 82 #include "absl/base/port.h" 83 #include "absl/strings/ascii.h" 84 #include "absl/strings/escaping.h" 85 #include "absl/strings/internal/stringify_sink.h" 86 #include "absl/strings/numbers.h" 87 #include "absl/strings/str_cat.h" 88 #include "absl/strings/str_split.h" 89 #include "absl/strings/string_view.h" 90 #include "absl/strings/strip.h" 91 92 namespace absl { 93 ABSL_NAMESPACE_BEGIN 94 namespace substitute_internal { 95 96 // Arg 97 // 98 // This class provides an argument type for `absl::Substitute()` and 99 // `absl::SubstituteAndAppend()`. `Arg` handles implicit conversion of various 100 // types to a string. (`Arg` is very similar to the `AlphaNum` class in 101 // `StrCat()`.) 102 // 103 // This class has implicit constructors. 104 class Arg { 105 public: 106 // Overloads for string-y things 107 // 108 // Explicitly overload `const char*` so the compiler doesn't cast to `bool`. 109 Arg(absl::Nullable<const char*> value) // NOLINT(google-explicit-constructor) 110 : piece_(absl::NullSafeStringView(value)) {} 111 template <typename Allocator> 112 Arg( // NOLINT 113 const std::basic_string<char, std::char_traits<char>, Allocator>& 114 value) noexcept 115 : piece_(value) {} 116 Arg(absl::string_view value) // NOLINT(google-explicit-constructor) 117 : piece_(value) {} 118 119 // Overloads for primitives 120 // 121 // No overloads are available for signed and unsigned char because if people 122 // are explicitly declaring their chars as signed or unsigned then they are 123 // probably using them as 8-bit integers and would probably prefer an integer 124 // representation. However, we can't really know, so we make the caller decide 125 // what to do. 126 Arg(char value) // NOLINT(google-explicit-constructor) 127 : piece_(scratch_, 1) { 128 scratch_[0] = value; 129 } 130 Arg(short value) // NOLINT(*) 131 : piece_(scratch_, 132 static_cast<size_t>( 133 numbers_internal::FastIntToBuffer(value, scratch_) - 134 scratch_)) {} 135 Arg(unsigned short value) // NOLINT(*) 136 : piece_(scratch_, 137 static_cast<size_t>( 138 numbers_internal::FastIntToBuffer(value, scratch_) - 139 scratch_)) {} 140 Arg(int value) // NOLINT(google-explicit-constructor) 141 : piece_(scratch_, 142 static_cast<size_t>( 143 numbers_internal::FastIntToBuffer(value, scratch_) - 144 scratch_)) {} 145 Arg(unsigned int value) // NOLINT(google-explicit-constructor) 146 : piece_(scratch_, 147 static_cast<size_t>( 148 numbers_internal::FastIntToBuffer(value, scratch_) - 149 scratch_)) {} 150 Arg(long value) // NOLINT(*) 151 : piece_(scratch_, 152 static_cast<size_t>( 153 numbers_internal::FastIntToBuffer(value, scratch_) - 154 scratch_)) {} 155 Arg(unsigned long value) // NOLINT(*) 156 : piece_(scratch_, 157 static_cast<size_t>( 158 numbers_internal::FastIntToBuffer(value, scratch_) - 159 scratch_)) {} 160 Arg(long long value) // NOLINT(*) 161 : piece_(scratch_, 162 static_cast<size_t>( 163 numbers_internal::FastIntToBuffer(value, scratch_) - 164 scratch_)) {} 165 Arg(unsigned long long value) // NOLINT(*) 166 : piece_(scratch_, 167 static_cast<size_t>( 168 numbers_internal::FastIntToBuffer(value, scratch_) - 169 scratch_)) {} 170 Arg(float value) // NOLINT(google-explicit-constructor) 171 : piece_(scratch_, numbers_internal::SixDigitsToBuffer(value, scratch_)) { 172 } 173 Arg(double value) // NOLINT(google-explicit-constructor) 174 : piece_(scratch_, numbers_internal::SixDigitsToBuffer(value, scratch_)) { 175 } 176 Arg(bool value) // NOLINT(google-explicit-constructor) 177 : piece_(value ? "true" : "false") {} 178 179 template <typename T, typename = typename std::enable_if< 180 HasAbslStringify<T>::value>::type> 181 Arg( // NOLINT(google-explicit-constructor) 182 const T& v, strings_internal::StringifySink&& sink = {}) 183 : piece_(strings_internal::ExtractStringification(sink, v)) {} 184 185 Arg(Hex hex); // NOLINT(google-explicit-constructor) 186 Arg(Dec dec); // NOLINT(google-explicit-constructor) 187 188 // vector<bool>::reference and const_reference require special help to convert 189 // to `Arg` because it requires two user defined conversions. 190 template <typename T, 191 absl::enable_if_t< 192 std::is_class<T>::value && 193 (std::is_same<T, std::vector<bool>::reference>::value || 194 std::is_same<T, std::vector<bool>::const_reference>::value)>* = 195 nullptr> 196 Arg(T value) // NOLINT(google-explicit-constructor) 197 : Arg(static_cast<bool>(value)) {} 198 199 // `void*` values, with the exception of `char*`, are printed as 200 // "0x<hex value>". However, in the case of `nullptr`, "NULL" is printed. 201 Arg( // NOLINT(google-explicit-constructor) 202 absl::Nullable<const void*> value); 203 204 // Normal enums are already handled by the integer formatters. 205 // This overload matches only scoped enums. 206 template <typename T, 207 typename = typename std::enable_if< 208 std::is_enum<T>{} && !std::is_convertible<T, int>{} && 209 !HasAbslStringify<T>::value>::type> 210 Arg(T value) // NOLINT(google-explicit-constructor) 211 : Arg(static_cast<typename std::underlying_type<T>::type>(value)) {} 212 213 Arg(const Arg&) = delete; 214 Arg& operator=(const Arg&) = delete; 215 216 absl::string_view piece() const { return piece_; } 217 218 private: 219 absl::string_view piece_; 220 char scratch_[numbers_internal::kFastToBufferSize]; 221 }; 222 223 // Internal helper function. Don't call this from outside this implementation. 224 // This interface may change without notice. 225 void SubstituteAndAppendArray( 226 absl::Nonnull<std::string*> output, absl::string_view format, 227 absl::Nullable<const absl::string_view*> args_array, size_t num_args); 228 229 #if defined(ABSL_BAD_CALL_IF) 230 constexpr int CalculateOneBit(absl::Nonnull<const char*> format) { 231 // Returns: 232 // * 2^N for '$N' when N is in [0-9] 233 // * 0 for correct '$' escaping: '$$'. 234 // * -1 otherwise. 235 return (*format < '0' || *format > '9') ? (*format == '$' ? 0 : -1) 236 : (1 << (*format - '0')); 237 } 238 239 constexpr const char* SkipNumber(absl::Nonnull<const char*> format) { 240 return !*format ? format : (format + 1); 241 } 242 243 constexpr int PlaceholderBitmask(absl::Nonnull<const char*> format) { 244 return !*format 245 ? 0 246 : *format != '$' ? PlaceholderBitmask(format + 1) 247 : (CalculateOneBit(format + 1) | 248 PlaceholderBitmask(SkipNumber(format + 1))); 249 } 250 #endif // ABSL_BAD_CALL_IF 251 252 } // namespace substitute_internal 253 254 // 255 // PUBLIC API 256 // 257 258 // SubstituteAndAppend() 259 // 260 // Substitutes variables into a given format string and appends to a given 261 // output string. See file comments above for usage. 262 // 263 // The declarations of `SubstituteAndAppend()` below consist of overloads 264 // for passing 0 to 10 arguments, respectively. 265 // 266 // NOTE: A zero-argument `SubstituteAndAppend()` may be used within variadic 267 // templates to allow a variable number of arguments. 268 // 269 // Example: 270 // template <typename... Args> 271 // void VarMsg(std::string* boilerplate, absl::string_view format, 272 // const Args&... args) { 273 // absl::SubstituteAndAppend(boilerplate, format, args...); 274 // } 275 // 276 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 277 absl::string_view format) { 278 substitute_internal::SubstituteAndAppendArray(output, format, nullptr, 0); 279 } 280 281 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 282 absl::string_view format, 283 const substitute_internal::Arg& a0) { 284 const absl::string_view args[] = {a0.piece()}; 285 substitute_internal::SubstituteAndAppendArray(output, format, args, 286 ABSL_ARRAYSIZE(args)); 287 } 288 289 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 290 absl::string_view format, 291 const substitute_internal::Arg& a0, 292 const substitute_internal::Arg& a1) { 293 const absl::string_view args[] = {a0.piece(), a1.piece()}; 294 substitute_internal::SubstituteAndAppendArray(output, format, args, 295 ABSL_ARRAYSIZE(args)); 296 } 297 298 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 299 absl::string_view format, 300 const substitute_internal::Arg& a0, 301 const substitute_internal::Arg& a1, 302 const substitute_internal::Arg& a2) { 303 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece()}; 304 substitute_internal::SubstituteAndAppendArray(output, format, args, 305 ABSL_ARRAYSIZE(args)); 306 } 307 308 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 309 absl::string_view format, 310 const substitute_internal::Arg& a0, 311 const substitute_internal::Arg& a1, 312 const substitute_internal::Arg& a2, 313 const substitute_internal::Arg& a3) { 314 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 315 a3.piece()}; 316 substitute_internal::SubstituteAndAppendArray(output, format, args, 317 ABSL_ARRAYSIZE(args)); 318 } 319 320 inline void SubstituteAndAppend(absl::Nonnull<std::string*> output, 321 absl::string_view format, 322 const substitute_internal::Arg& a0, 323 const substitute_internal::Arg& a1, 324 const substitute_internal::Arg& a2, 325 const substitute_internal::Arg& a3, 326 const substitute_internal::Arg& a4) { 327 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 328 a3.piece(), a4.piece()}; 329 substitute_internal::SubstituteAndAppendArray(output, format, args, 330 ABSL_ARRAYSIZE(args)); 331 } 332 333 inline void SubstituteAndAppend( 334 absl::Nonnull<std::string*> output, absl::string_view format, 335 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 336 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 337 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5) { 338 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 339 a3.piece(), a4.piece(), a5.piece()}; 340 substitute_internal::SubstituteAndAppendArray(output, format, args, 341 ABSL_ARRAYSIZE(args)); 342 } 343 344 inline void SubstituteAndAppend( 345 absl::Nonnull<std::string*> output, absl::string_view format, 346 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 347 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 348 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 349 const substitute_internal::Arg& a6) { 350 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 351 a3.piece(), a4.piece(), a5.piece(), 352 a6.piece()}; 353 substitute_internal::SubstituteAndAppendArray(output, format, args, 354 ABSL_ARRAYSIZE(args)); 355 } 356 357 inline void SubstituteAndAppend( 358 absl::Nonnull<std::string*> output, absl::string_view format, 359 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 360 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 361 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 362 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7) { 363 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 364 a3.piece(), a4.piece(), a5.piece(), 365 a6.piece(), a7.piece()}; 366 substitute_internal::SubstituteAndAppendArray(output, format, args, 367 ABSL_ARRAYSIZE(args)); 368 } 369 370 inline void SubstituteAndAppend( 371 absl::Nonnull<std::string*> output, absl::string_view format, 372 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 373 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 374 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 375 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7, 376 const substitute_internal::Arg& a8) { 377 const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(), 378 a3.piece(), a4.piece(), a5.piece(), 379 a6.piece(), a7.piece(), a8.piece()}; 380 substitute_internal::SubstituteAndAppendArray(output, format, args, 381 ABSL_ARRAYSIZE(args)); 382 } 383 384 inline void SubstituteAndAppend( 385 absl::Nonnull<std::string*> output, absl::string_view format, 386 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 387 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 388 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 389 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7, 390 const substitute_internal::Arg& a8, const substitute_internal::Arg& a9) { 391 const absl::string_view args[] = { 392 a0.piece(), a1.piece(), a2.piece(), a3.piece(), a4.piece(), 393 a5.piece(), a6.piece(), a7.piece(), a8.piece(), a9.piece()}; 394 substitute_internal::SubstituteAndAppendArray(output, format, args, 395 ABSL_ARRAYSIZE(args)); 396 } 397 398 #if defined(ABSL_BAD_CALL_IF) 399 // This body of functions catches cases where the number of placeholders 400 // doesn't match the number of data arguments. 401 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 402 absl::Nonnull<const char*> format) 403 ABSL_BAD_CALL_IF( 404 substitute_internal::PlaceholderBitmask(format) != 0, 405 "There were no substitution arguments " 406 "but this format string either has a $[0-9] in it or contains " 407 "an unescaped $ character (use $$ instead)"); 408 409 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 410 absl::Nonnull<const char*> format, 411 const substitute_internal::Arg& a0) 412 ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 1, 413 "There was 1 substitution argument given, but " 414 "this format string is missing its $0, contains " 415 "one of $1-$9, or contains an unescaped $ character (use " 416 "$$ instead)"); 417 418 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 419 absl::Nonnull<const char*> format, 420 const substitute_internal::Arg& a0, 421 const substitute_internal::Arg& a1) 422 ABSL_BAD_CALL_IF( 423 substitute_internal::PlaceholderBitmask(format) != 3, 424 "There were 2 substitution arguments given, but this format string is " 425 "missing its $0/$1, contains one of $2-$9, or contains an " 426 "unescaped $ character (use $$ instead)"); 427 428 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 429 absl::Nonnull<const char*> format, 430 const substitute_internal::Arg& a0, 431 const substitute_internal::Arg& a1, 432 const substitute_internal::Arg& a2) 433 ABSL_BAD_CALL_IF( 434 substitute_internal::PlaceholderBitmask(format) != 7, 435 "There were 3 substitution arguments given, but " 436 "this format string is missing its $0/$1/$2, contains one of " 437 "$3-$9, or contains an unescaped $ character (use $$ instead)"); 438 439 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 440 absl::Nonnull<const char*> format, 441 const substitute_internal::Arg& a0, 442 const substitute_internal::Arg& a1, 443 const substitute_internal::Arg& a2, 444 const substitute_internal::Arg& a3) 445 ABSL_BAD_CALL_IF( 446 substitute_internal::PlaceholderBitmask(format) != 15, 447 "There were 4 substitution arguments given, but " 448 "this format string is missing its $0-$3, contains one of " 449 "$4-$9, or contains an unescaped $ character (use $$ instead)"); 450 451 void SubstituteAndAppend(absl::Nonnull<std::string*> output, 452 absl::Nonnull<const char*> format, 453 const substitute_internal::Arg& a0, 454 const substitute_internal::Arg& a1, 455 const substitute_internal::Arg& a2, 456 const substitute_internal::Arg& a3, 457 const substitute_internal::Arg& a4) 458 ABSL_BAD_CALL_IF( 459 substitute_internal::PlaceholderBitmask(format) != 31, 460 "There were 5 substitution arguments given, but " 461 "this format string is missing its $0-$4, contains one of " 462 "$5-$9, or contains an unescaped $ character (use $$ instead)"); 463 464 void SubstituteAndAppend( 465 absl::Nonnull<std::string*> output, absl::Nonnull<const char*> format, 466 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 467 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 468 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5) 469 ABSL_BAD_CALL_IF( 470 substitute_internal::PlaceholderBitmask(format) != 63, 471 "There were 6 substitution arguments given, but " 472 "this format string is missing its $0-$5, contains one of " 473 "$6-$9, or contains an unescaped $ character (use $$ instead)"); 474 475 void SubstituteAndAppend( 476 absl::Nonnull<std::string*> output, absl::Nonnull<const char*> format, 477 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 478 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 479 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 480 const substitute_internal::Arg& a6) 481 ABSL_BAD_CALL_IF( 482 substitute_internal::PlaceholderBitmask(format) != 127, 483 "There were 7 substitution arguments given, but " 484 "this format string is missing its $0-$6, contains one of " 485 "$7-$9, or contains an unescaped $ character (use $$ instead)"); 486 487 void SubstituteAndAppend( 488 absl::Nonnull<std::string*> output, absl::Nonnull<const char*> format, 489 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 490 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 491 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 492 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7) 493 ABSL_BAD_CALL_IF( 494 substitute_internal::PlaceholderBitmask(format) != 255, 495 "There were 8 substitution arguments given, but " 496 "this format string is missing its $0-$7, contains one of " 497 "$8-$9, or contains an unescaped $ character (use $$ instead)"); 498 499 void SubstituteAndAppend( 500 absl::Nonnull<std::string*> output, absl::Nonnull<const char*> format, 501 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 502 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 503 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 504 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7, 505 const substitute_internal::Arg& a8) 506 ABSL_BAD_CALL_IF( 507 substitute_internal::PlaceholderBitmask(format) != 511, 508 "There were 9 substitution arguments given, but " 509 "this format string is missing its $0-$8, contains a $9, or " 510 "contains an unescaped $ character (use $$ instead)"); 511 512 void SubstituteAndAppend( 513 absl::Nonnull<std::string*> output, absl::Nonnull<const char*> format, 514 const substitute_internal::Arg& a0, const substitute_internal::Arg& a1, 515 const substitute_internal::Arg& a2, const substitute_internal::Arg& a3, 516 const substitute_internal::Arg& a4, const substitute_internal::Arg& a5, 517 const substitute_internal::Arg& a6, const substitute_internal::Arg& a7, 518 const substitute_internal::Arg& a8, const substitute_internal::Arg& a9) 519 ABSL_BAD_CALL_IF( 520 substitute_internal::PlaceholderBitmask(format) != 1023, 521 "There were 10 substitution arguments given, but this " 522 "format string either doesn't contain all of $0 through $9 or " 523 "contains an unescaped $ character (use $$ instead)"); 524 #endif // ABSL_BAD_CALL_IF 525 526 // Substitute() 527 // 528 // Substitutes variables into a given format string. See file comments above 529 // for usage. 530 // 531 // The declarations of `Substitute()` below consist of overloads for passing 0 532 // to 10 arguments, respectively. 533 // 534 // NOTE: A zero-argument `Substitute()` may be used within variadic templates to 535 // allow a variable number of arguments. 536 // 537 // Example: 538 // template <typename... Args> 539 // void VarMsg(absl::string_view format, const Args&... args) { 540 // std::string s = absl::Substitute(format, args...); 541 542 [[nodiscard]] inline std::string Substitute(absl::string_view format) { 543 std::string result; 544 SubstituteAndAppend(&result, format); 545 return result; 546 } 547 548 [[nodiscard]] inline std::string Substitute( 549 absl::string_view format, const substitute_internal::Arg& a0) { 550 std::string result; 551 SubstituteAndAppend(&result, format, a0); 552 return result; 553 } 554 555 [[nodiscard]] inline std::string Substitute( 556 absl::string_view format, const substitute_internal::Arg& a0, 557 const substitute_internal::Arg& a1) { 558 std::string result; 559 SubstituteAndAppend(&result, format, a0, a1); 560 return result; 561 } 562 563 [[nodiscard]] inline std::string Substitute( 564 absl::string_view format, const substitute_internal::Arg& a0, 565 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2) { 566 std::string result; 567 SubstituteAndAppend(&result, format, a0, a1, a2); 568 return result; 569 } 570 571 [[nodiscard]] inline std::string Substitute( 572 absl::string_view format, const substitute_internal::Arg& a0, 573 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 574 const substitute_internal::Arg& a3) { 575 std::string result; 576 SubstituteAndAppend(&result, format, a0, a1, a2, a3); 577 return result; 578 } 579 580 [[nodiscard]] inline std::string Substitute( 581 absl::string_view format, const substitute_internal::Arg& a0, 582 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 583 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4) { 584 std::string result; 585 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4); 586 return result; 587 } 588 589 [[nodiscard]] inline std::string Substitute( 590 absl::string_view format, const substitute_internal::Arg& a0, 591 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 592 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 593 const substitute_internal::Arg& a5) { 594 std::string result; 595 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5); 596 return result; 597 } 598 599 [[nodiscard]] inline std::string Substitute( 600 absl::string_view format, const substitute_internal::Arg& a0, 601 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 602 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 603 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6) { 604 std::string result; 605 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6); 606 return result; 607 } 608 609 [[nodiscard]] inline std::string Substitute( 610 absl::string_view format, const substitute_internal::Arg& a0, 611 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 612 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 613 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 614 const substitute_internal::Arg& a7) { 615 std::string result; 616 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7); 617 return result; 618 } 619 620 [[nodiscard]] inline std::string Substitute( 621 absl::string_view format, const substitute_internal::Arg& a0, 622 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 623 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 624 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 625 const substitute_internal::Arg& a7, const substitute_internal::Arg& a8) { 626 std::string result; 627 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7, a8); 628 return result; 629 } 630 631 [[nodiscard]] inline std::string Substitute( 632 absl::string_view format, const substitute_internal::Arg& a0, 633 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 634 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 635 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 636 const substitute_internal::Arg& a7, const substitute_internal::Arg& a8, 637 const substitute_internal::Arg& a9) { 638 std::string result; 639 SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); 640 return result; 641 } 642 643 #if defined(ABSL_BAD_CALL_IF) 644 // This body of functions catches cases where the number of placeholders 645 // doesn't match the number of data arguments. 646 std::string Substitute(absl::Nonnull<const char*> format) 647 ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 0, 648 "There were no substitution arguments " 649 "but this format string either has a $[0-9] in it or " 650 "contains an unescaped $ character (use $$ instead)"); 651 652 std::string Substitute(absl::Nonnull<const char*> format, 653 const substitute_internal::Arg& a0) 654 ABSL_BAD_CALL_IF( 655 substitute_internal::PlaceholderBitmask(format) != 1, 656 "There was 1 substitution argument given, but " 657 "this format string is missing its $0, contains one of $1-$9, " 658 "or contains an unescaped $ character (use $$ instead)"); 659 660 std::string Substitute(absl::Nonnull<const char*> format, 661 const substitute_internal::Arg& a0, 662 const substitute_internal::Arg& a1) 663 ABSL_BAD_CALL_IF( 664 substitute_internal::PlaceholderBitmask(format) != 3, 665 "There were 2 substitution arguments given, but " 666 "this format string is missing its $0/$1, contains one of " 667 "$2-$9, or contains an unescaped $ character (use $$ instead)"); 668 669 std::string Substitute(absl::Nonnull<const char*> format, 670 const substitute_internal::Arg& a0, 671 const substitute_internal::Arg& a1, 672 const substitute_internal::Arg& a2) 673 ABSL_BAD_CALL_IF( 674 substitute_internal::PlaceholderBitmask(format) != 7, 675 "There were 3 substitution arguments given, but " 676 "this format string is missing its $0/$1/$2, contains one of " 677 "$3-$9, or contains an unescaped $ character (use $$ instead)"); 678 679 std::string Substitute(absl::Nonnull<const char*> format, 680 const substitute_internal::Arg& a0, 681 const substitute_internal::Arg& a1, 682 const substitute_internal::Arg& a2, 683 const substitute_internal::Arg& a3) 684 ABSL_BAD_CALL_IF( 685 substitute_internal::PlaceholderBitmask(format) != 15, 686 "There were 4 substitution arguments given, but " 687 "this format string is missing its $0-$3, contains one of " 688 "$4-$9, or contains an unescaped $ character (use $$ instead)"); 689 690 std::string Substitute(absl::Nonnull<const char*> format, 691 const substitute_internal::Arg& a0, 692 const substitute_internal::Arg& a1, 693 const substitute_internal::Arg& a2, 694 const substitute_internal::Arg& a3, 695 const substitute_internal::Arg& a4) 696 ABSL_BAD_CALL_IF( 697 substitute_internal::PlaceholderBitmask(format) != 31, 698 "There were 5 substitution arguments given, but " 699 "this format string is missing its $0-$4, contains one of " 700 "$5-$9, or contains an unescaped $ character (use $$ instead)"); 701 702 std::string Substitute(absl::Nonnull<const char*> format, 703 const substitute_internal::Arg& a0, 704 const substitute_internal::Arg& a1, 705 const substitute_internal::Arg& a2, 706 const substitute_internal::Arg& a3, 707 const substitute_internal::Arg& a4, 708 const substitute_internal::Arg& a5) 709 ABSL_BAD_CALL_IF( 710 substitute_internal::PlaceholderBitmask(format) != 63, 711 "There were 6 substitution arguments given, but " 712 "this format string is missing its $0-$5, contains one of " 713 "$6-$9, or contains an unescaped $ character (use $$ instead)"); 714 715 std::string Substitute( 716 absl::Nonnull<const char*> format, const substitute_internal::Arg& a0, 717 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 718 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 719 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6) 720 ABSL_BAD_CALL_IF( 721 substitute_internal::PlaceholderBitmask(format) != 127, 722 "There were 7 substitution arguments given, but " 723 "this format string is missing its $0-$6, contains one of " 724 "$7-$9, or contains an unescaped $ character (use $$ instead)"); 725 726 std::string Substitute( 727 absl::Nonnull<const char*> format, const substitute_internal::Arg& a0, 728 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 729 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 730 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 731 const substitute_internal::Arg& a7) 732 ABSL_BAD_CALL_IF( 733 substitute_internal::PlaceholderBitmask(format) != 255, 734 "There were 8 substitution arguments given, but " 735 "this format string is missing its $0-$7, contains one of " 736 "$8-$9, or contains an unescaped $ character (use $$ instead)"); 737 738 std::string Substitute( 739 absl::Nonnull<const char*> format, const substitute_internal::Arg& a0, 740 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 741 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 742 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 743 const substitute_internal::Arg& a7, const substitute_internal::Arg& a8) 744 ABSL_BAD_CALL_IF( 745 substitute_internal::PlaceholderBitmask(format) != 511, 746 "There were 9 substitution arguments given, but " 747 "this format string is missing its $0-$8, contains a $9, or " 748 "contains an unescaped $ character (use $$ instead)"); 749 750 std::string Substitute( 751 absl::Nonnull<const char*> format, const substitute_internal::Arg& a0, 752 const substitute_internal::Arg& a1, const substitute_internal::Arg& a2, 753 const substitute_internal::Arg& a3, const substitute_internal::Arg& a4, 754 const substitute_internal::Arg& a5, const substitute_internal::Arg& a6, 755 const substitute_internal::Arg& a7, const substitute_internal::Arg& a8, 756 const substitute_internal::Arg& a9) 757 ABSL_BAD_CALL_IF( 758 substitute_internal::PlaceholderBitmask(format) != 1023, 759 "There were 10 substitution arguments given, but this " 760 "format string either doesn't contain all of $0 through $9 or " 761 "contains an unescaped $ character (use $$ instead)"); 762 #endif // ABSL_BAD_CALL_IF 763 764 ABSL_NAMESPACE_END 765 } // namespace absl 766 767 #endif // ABSL_STRINGS_SUBSTITUTE_H_