1 //===- llvm/ADT/StringExtras.h - Useful string functions --------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains some functions that are useful when dealing with strings. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_ADT_STRINGEXTRAS_H 14 #define LLVM_ADT_STRINGEXTRAS_H 15 16 #include "llvm/ADT/ArrayRef.h" 17 #include "llvm/ADT/SmallString.h" 18 #include "llvm/ADT/StringRef.h" 19 #include "llvm/ADT/Twine.h" 20 #include <cassert> 21 #include <cstddef> 22 #include <cstdint> 23 #include <cstdlib> 24 #include <cstring> 25 #include <iterator> 26 #include <string> 27 #include <utility> 28 29 namespace llvm { 30 31 template<typename T> class SmallVectorImpl; 32 class raw_ostream; 33 34 /// hexdigit - Return the hexadecimal character for the 35 /// given number \p X (which should be less than 16). 36 inline char hexdigit(unsigned X, bool LowerCase = false) { 37 const char HexChar = LowerCase ? 'a' : 'A'; 38 return X < 10 ? '0' + X : HexChar + X - 10; 39 } 40 41 /// Given an array of c-style strings terminated by a null pointer, construct 42 /// a vector of StringRefs representing the same strings without the terminating 43 /// null string. 44 inline std::vector<StringRef> toStringRefArray(const char *const *Strings) { 45 std::vector<StringRef> Result; 46 while (*Strings) 47 Result.push_back(*Strings++); 48 return Result; 49 } 50 51 /// Construct a string ref from a boolean. 52 inline StringRef toStringRef(bool B) { return StringRef(B ? "true" : "false"); } 53 54 /// Construct a string ref from an array ref of unsigned chars. 55 inline StringRef toStringRef(ArrayRef<uint8_t> Input) { 56 return StringRef(reinterpret_cast<const char *>(Input.begin()), Input.size()); 57 } 58 59 /// Construct a string ref from an array ref of unsigned chars. 60 inline ArrayRef<uint8_t> arrayRefFromStringRef(StringRef Input) { 61 return {Input.bytes_begin(), Input.bytes_end()}; 62 } 63 64 /// Interpret the given character \p C as a hexadecimal digit and return its 65 /// value. 66 /// 67 /// If \p C is not a valid hex digit, -1U is returned. 68 inline unsigned hexDigitValue(char C) { 69 struct HexTable { 70 unsigned LUT[255] = {}; 71 constexpr HexTable() { 72 // Default initialize everything to invalid. 73 for (int i = 0; i < 255; ++i) 74 LUT[i] = ~0U; 75 // Initialize `0`-`9`. 76 for (int i = 0; i < 10; ++i) 77 LUT['0' + i] = i; 78 // Initialize `A`-`F` and `a`-`f`. 79 for (int i = 0; i < 6; ++i) 80 LUT['A' + i] = LUT['a' + i] = 10 + i; 81 } 82 }; 83 constexpr HexTable Table; 84 return Table.LUT[static_cast<unsigned char>(C)]; 85 } 86 87 /// Checks if character \p C is one of the 10 decimal digits. 88 inline bool isDigit(char C) { return C >= '0' && C <= '9'; } 89 90 /// Checks if character \p C is a hexadecimal numeric character. 91 inline bool isHexDigit(char C) { return hexDigitValue(C) != ~0U; } 92 93 /// Checks if character \p C is a valid letter as classified by "C" locale. 94 inline bool isAlpha(char C) { 95 return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z'); 96 } 97 98 /// Checks whether character \p C is either a decimal digit or an uppercase or 99 /// lowercase letter as classified by "C" locale. 100 inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); } 101 102 /// Checks whether character \p C is valid ASCII (high bit is zero). 103 inline bool isASCII(char C) { return static_cast<unsigned char>(C) <= 127; } 104 105 /// Checks whether all characters in S are ASCII. 106 inline bool isASCII(llvm::StringRef S) { 107 for (char C : S) 108 if (LLVM_UNLIKELY(!isASCII(C))) 109 return false; 110 return true; 111 } 112 113 /// Checks whether character \p C is printable. 114 /// 115 /// Locale-independent version of the C standard library isprint whose results 116 /// may differ on different platforms. 117 inline bool isPrint(char C) { 118 unsigned char UC = static_cast<unsigned char>(C); 119 return (0x20 <= UC) && (UC <= 0x7E); 120 } 121 122 /// Checks whether character \p C is whitespace in the "C" locale. 123 /// 124 /// Locale-independent version of the C standard library isspace. 125 inline bool isSpace(char C) { 126 return C == ' ' || C == '\f' || C == '\n' || C == '\r' || C == '\t' || 127 C == '\v'; 128 } 129 130 /// Returns the corresponding lowercase character if \p x is uppercase. 131 inline char toLower(char x) { 132 if (x >= 'A' && x <= 'Z') 133 return x - 'A' + 'a'; 134 return x; 135 } 136 137 /// Returns the corresponding uppercase character if \p x is lowercase. 138 inline char toUpper(char x) { 139 if (x >= 'a' && x <= 'z') 140 return x - 'a' + 'A'; 141 return x; 142 } 143 144 inline std::string utohexstr(uint64_t X, bool LowerCase = false) { 145 char Buffer[17]; 146 char *BufPtr = std::end(Buffer); 147 148 if (X == 0) *--BufPtr = '0'; 149 150 while (X) { 151 unsigned char Mod = static_cast<unsigned char>(X) & 15; 152 *--BufPtr = hexdigit(Mod, LowerCase); 153 X >>= 4; 154 } 155 156 return std::string(BufPtr, std::end(Buffer)); 157 } 158 159 /// Convert buffer \p Input to its hexadecimal representation. 160 /// The returned string is double the size of \p Input. 161 inline std::string toHex(StringRef Input, bool LowerCase = false) { 162 static const char *const LUT = "0123456789ABCDEF"; 163 const uint8_t Offset = LowerCase ? 32 : 0; 164 size_t Length = Input.size(); 165 166 std::string Output; 167 Output.reserve(2 * Length); 168 for (size_t i = 0; i < Length; ++i) { 169 const unsigned char c = Input[i]; 170 Output.push_back(LUT[c >> 4] | Offset); 171 Output.push_back(LUT[c & 15] | Offset); 172 } 173 return Output; 174 } 175 176 inline std::string toHex(ArrayRef<uint8_t> Input, bool LowerCase = false) { 177 return toHex(toStringRef(Input), LowerCase); 178 } 179 180 /// Store the binary representation of the two provided values, \p MSB and 181 /// \p LSB, that make up the nibbles of a hexadecimal digit. If \p MSB or \p LSB 182 /// do not correspond to proper nibbles of a hexadecimal digit, this method 183 /// returns false. Otherwise, returns true. 184 inline bool tryGetHexFromNibbles(char MSB, char LSB, uint8_t &Hex) { 185 unsigned U1 = hexDigitValue(MSB); 186 unsigned U2 = hexDigitValue(LSB); 187 if (U1 == ~0U || U2 == ~0U) 188 return false; 189 190 Hex = static_cast<uint8_t>((U1 << 4) | U2); 191 return true; 192 } 193 194 /// Return the binary representation of the two provided values, \p MSB and 195 /// \p LSB, that make up the nibbles of a hexadecimal digit. 196 inline uint8_t hexFromNibbles(char MSB, char LSB) { 197 uint8_t Hex = 0; 198 bool GotHex = tryGetHexFromNibbles(MSB, LSB, Hex); 199 (void)GotHex; 200 assert(GotHex && "MSB and/or LSB do not correspond to hex digits"); 201 return Hex; 202 } 203 204 /// Convert hexadecimal string \p Input to its binary representation and store 205 /// the result in \p Output. Returns true if the binary representation could be 206 /// converted from the hexadecimal string. Returns false if \p Input contains 207 /// non-hexadecimal digits. The output string is half the size of \p Input. 208 inline bool tryGetFromHex(StringRef Input, std::string &Output) { 209 if (Input.empty()) 210 return true; 211 212 Output.reserve((Input.size() + 1) / 2); 213 if (Input.size() % 2 == 1) { 214 uint8_t Hex = 0; 215 if (!tryGetHexFromNibbles('0', Input.front(), Hex)) 216 return false; 217 218 Output.push_back(Hex); 219 Input = Input.drop_front(); 220 } 221 222 assert(Input.size() % 2 == 0); 223 while (!Input.empty()) { 224 uint8_t Hex = 0; 225 if (!tryGetHexFromNibbles(Input[0], Input[1], Hex)) 226 return false; 227 228 Output.push_back(Hex); 229 Input = Input.drop_front(2); 230 } 231 return true; 232 } 233 234 /// Convert hexadecimal string \p Input to its binary representation. 235 /// The return string is half the size of \p Input. 236 inline std::string fromHex(StringRef Input) { 237 std::string Hex; 238 bool GotHex = tryGetFromHex(Input, Hex); 239 (void)GotHex; 240 assert(GotHex && "Input contains non hex digits"); 241 return Hex; 242 } 243 244 /// Convert the string \p S to an integer of the specified type using 245 /// the radix \p Base. If \p Base is 0, auto-detects the radix. 246 /// Returns true if the number was successfully converted, false otherwise. 247 template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) { 248 return !S.getAsInteger(Base, Num); 249 } 250 251 namespace detail { 252 template <typename N> 253 inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) { 254 SmallString<32> Storage; 255 StringRef S = T.toNullTerminatedStringRef(Storage); 256 char *End; 257 N Temp = StrTo(S.data(), &End); 258 if (*End != '\0') 259 return false; 260 Num = Temp; 261 return true; 262 } 263 } 264 265 inline bool to_float(const Twine &T, float &Num) { 266 return detail::to_float(T, Num, strtof); 267 } 268 269 inline bool to_float(const Twine &T, double &Num) { 270 return detail::to_float(T, Num, strtod); 271 } 272 273 inline bool to_float(const Twine &T, long double &Num) { 274 return detail::to_float(T, Num, strtold); 275 } 276 277 inline std::string utostr(uint64_t X, bool isNeg = false) { 278 char Buffer[21]; 279 char *BufPtr = std::end(Buffer); 280 281 if (X == 0) *--BufPtr = '0'; // Handle special case... 282 283 while (X) { 284 *--BufPtr = '0' + char(X % 10); 285 X /= 10; 286 } 287 288 if (isNeg) *--BufPtr = '-'; // Add negative sign... 289 return std::string(BufPtr, std::end(Buffer)); 290 } 291 292 inline std::string itostr(int64_t X) { 293 if (X < 0) 294 return utostr(static_cast<uint64_t>(1) + ~static_cast<uint64_t>(X), true); 295 else 296 return utostr(static_cast<uint64_t>(X)); 297 } 298 299 /// StrInStrNoCase - Portable version of strcasestr. Locates the first 300 /// occurrence of string 's1' in string 's2', ignoring case. Returns 301 /// the offset of s2 in s1 or npos if s2 cannot be found. 302 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2); 303 304 /// getToken - This function extracts one token from source, ignoring any 305 /// leading characters that appear in the Delimiters string, and ending the 306 /// token at any of the characters that appear in the Delimiters string. If 307 /// there are no tokens in the source string, an empty string is returned. 308 /// The function returns a pair containing the extracted token and the 309 /// remaining tail string. 310 std::pair<StringRef, StringRef> getToken(StringRef Source, 311 StringRef Delimiters = " \t\n\v\f\r"); 312 313 /// SplitString - Split up the specified string according to the specified 314 /// delimiters, appending the result fragments to the output list. 315 void SplitString(StringRef Source, 316 SmallVectorImpl<StringRef> &OutFragments, 317 StringRef Delimiters = " \t\n\v\f\r"); 318 319 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th). 320 inline StringRef getOrdinalSuffix(unsigned Val) { 321 // It is critically important that we do this perfectly for 322 // user-written sequences with over 100 elements. 323 switch (Val % 100) { 324 case 11: 325 case 12: 326 case 13: 327 return "th"; 328 default: 329 switch (Val % 10) { 330 case 1: return "st"; 331 case 2: return "nd"; 332 case 3: return "rd"; 333 default: return "th"; 334 } 335 } 336 } 337 338 /// Print each character of the specified string, escaping it if it is not 339 /// printable or if it is an escape char. 340 void printEscapedString(StringRef Name, raw_ostream &Out); 341 342 /// Print each character of the specified string, escaping HTML special 343 /// characters. 344 void printHTMLEscaped(StringRef String, raw_ostream &Out); 345 346 /// printLowerCase - Print each character as lowercase if it is uppercase. 347 void printLowerCase(StringRef String, raw_ostream &Out); 348 349 /// Converts a string from camel-case to snake-case by replacing all uppercase 350 /// letters with '_' followed by the letter in lowercase, except if the 351 /// uppercase letter is the first character of the string. 352 std::string convertToSnakeFromCamelCase(StringRef input); 353 354 /// Converts a string from snake-case to camel-case by replacing all occurrences 355 /// of '_' followed by a lowercase letter with the letter in uppercase. 356 /// Optionally allow capitalization of the first letter (if it is a lowercase 357 /// letter) 358 std::string convertToCamelFromSnakeCase(StringRef input, 359 bool capitalizeFirst = false); 360 361 namespace detail { 362 363 template <typename IteratorT> 364 inline std::string join_impl(IteratorT Begin, IteratorT End, 365 StringRef Separator, std::input_iterator_tag) { 366 std::string S; 367 if (Begin == End) 368 return S; 369 370 S += (*Begin); 371 while (++Begin != End) { 372 S += Separator; 373 S += (*Begin); 374 } 375 return S; 376 } 377 378 template <typename IteratorT> 379 inline std::string join_impl(IteratorT Begin, IteratorT End, 380 StringRef Separator, std::forward_iterator_tag) { 381 std::string S; 382 if (Begin == End) 383 return S; 384 385 size_t Len = (std::distance(Begin, End) - 1) * Separator.size(); 386 for (IteratorT I = Begin; I != End; ++I) 387 Len += (*I).size(); 388 S.reserve(Len); 389 size_t PrevCapacity = S.capacity(); 390 (void)PrevCapacity; 391 S += (*Begin); 392 while (++Begin != End) { 393 S += Separator; 394 S += (*Begin); 395 } 396 assert(PrevCapacity == S.capacity() && "String grew during building"); 397 return S; 398 } 399 400 template <typename Sep> 401 inline void join_items_impl(std::string &Result, Sep Separator) {} 402 403 template <typename Sep, typename Arg> 404 inline void join_items_impl(std::string &Result, Sep Separator, 405 const Arg &Item) { 406 Result += Item; 407 } 408 409 template <typename Sep, typename Arg1, typename... Args> 410 inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1, 411 Args &&... Items) { 412 Result += A1; 413 Result += Separator; 414 join_items_impl(Result, Separator, std::forward<Args>(Items)...); 415 } 416 417 inline size_t join_one_item_size(char) { return 1; } 418 inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; } 419 420 template <typename T> inline size_t join_one_item_size(const T &Str) { 421 return Str.size(); 422 } 423 424 inline size_t join_items_size() { return 0; } 425 426 template <typename A1> inline size_t join_items_size(const A1 &A) { 427 return join_one_item_size(A); 428 } 429 template <typename A1, typename... Args> 430 inline size_t join_items_size(const A1 &A, Args &&... Items) { 431 return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...); 432 } 433 434 } // end namespace detail 435 436 /// Joins the strings in the range [Begin, End), adding Separator between 437 /// the elements. 438 template <typename IteratorT> 439 inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) { 440 using tag = typename std::iterator_traits<IteratorT>::iterator_category; 441 return detail::join_impl(Begin, End, Separator, tag()); 442 } 443 444 /// Joins the strings in the range [R.begin(), R.end()), adding Separator 445 /// between the elements. 446 template <typename Range> 447 inline std::string join(Range &&R, StringRef Separator) { 448 return join(R.begin(), R.end(), Separator); 449 } 450 451 /// Joins the strings in the parameter pack \p Items, adding \p Separator 452 /// between the elements. All arguments must be implicitly convertible to 453 /// std::string, or there should be an overload of std::string::operator+=() 454 /// that accepts the argument explicitly. 455 template <typename Sep, typename... Args> 456 inline std::string join_items(Sep Separator, Args &&... Items) { 457 std::string Result; 458 if (sizeof...(Items) == 0) 459 return Result; 460 461 size_t NS = detail::join_one_item_size(Separator); 462 size_t NI = detail::join_items_size(std::forward<Args>(Items)...); 463 Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1); 464 detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...); 465 return Result; 466 } 467 468 /// A helper class to return the specified delimiter string after the first 469 /// invocation of operator StringRef(). Used to generate a comma-separated 470 /// list from a loop like so: 471 /// 472 /// \code 473 /// ListSeparator LS; 474 /// for (auto &I : C) 475 /// OS << LS << I.getName(); 476 /// \end 477 class ListSeparator { 478 bool First = true; 479 StringRef Separator; 480 481 public: 482 ListSeparator(StringRef Separator = ", ") : Separator(Separator) {} 483 operator StringRef() { 484 if (First) { 485 First = false; 486 return {}; 487 } 488 return Separator; 489 } 490 }; 491 492 } // end namespace llvm 493 494 #endif // LLVM_ADT_STRINGEXTRAS_H 495