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 if (C >= '0' && C <= '9') return C-'0'; 70 if (C >= 'a' && C <= 'f') return C-'a'+10U; 71 if (C >= 'A' && C <= 'F') return C-'A'+10U; 72 return -1U; 73 } 74 75 /// Checks if character \p C is one of the 10 decimal digits. 76 inline bool isDigit(char C) { return C >= '0' && C <= '9'; } 77 78 /// Checks if character \p C is a hexadecimal numeric character. 79 inline bool isHexDigit(char C) { return hexDigitValue(C) != -1U; } 80 81 /// Checks if character \p C is a valid letter as classified by "C" locale. 82 inline bool isAlpha(char C) { 83 return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z'); 84 } 85 86 /// Checks whether character \p C is either a decimal digit or an uppercase or 87 /// lowercase letter as classified by "C" locale. 88 inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); } 89 90 /// Checks whether character \p C is valid ASCII (high bit is zero). 91 inline bool isASCII(char C) { return static_cast<unsigned char>(C) <= 127; } 92 93 /// Checks whether all characters in S are ASCII. 94 inline bool isASCII(llvm::StringRef S) { 95 for (char C : S) 96 if (LLVM_UNLIKELY(!isASCII(C))) 97 return false; 98 return true; 99 } 100 101 /// Checks whether character \p C is printable. 102 /// 103 /// Locale-independent version of the C standard library isprint whose results 104 /// may differ on different platforms. 105 inline bool isPrint(char C) { 106 unsigned char UC = static_cast<unsigned char>(C); 107 return (0x20 <= UC) && (UC <= 0x7E); 108 } 109 110 /// Checks whether character \p C is whitespace in the "C" locale. 111 /// 112 /// Locale-independent version of the C standard library isspace. 113 inline bool isSpace(char C) { 114 return C == ' ' || C == '\f' || C == '\n' || C == '\r' || C == '\t' || 115 C == '\v'; 116 } 117 118 /// Returns the corresponding lowercase character if \p x is uppercase. 119 inline char toLower(char x) { 120 if (x >= 'A' && x <= 'Z') 121 return x - 'A' + 'a'; 122 return x; 123 } 124 125 /// Returns the corresponding uppercase character if \p x is lowercase. 126 inline char toUpper(char x) { 127 if (x >= 'a' && x <= 'z') 128 return x - 'a' + 'A'; 129 return x; 130 } 131 132 inline std::string utohexstr(uint64_t X, bool LowerCase = false) { 133 char Buffer[17]; 134 char *BufPtr = std::end(Buffer); 135 136 if (X == 0) *--BufPtr = '0'; 137 138 while (X) { 139 unsigned char Mod = static_cast<unsigned char>(X) & 15; 140 *--BufPtr = hexdigit(Mod, LowerCase); 141 X >>= 4; 142 } 143 144 return std::string(BufPtr, std::end(Buffer)); 145 } 146 147 /// Convert buffer \p Input to its hexadecimal representation. 148 /// The returned string is double the size of \p Input. 149 inline std::string toHex(StringRef Input, bool LowerCase = false) { 150 static const char *const LUT = "0123456789ABCDEF"; 151 const uint8_t Offset = LowerCase ? 32 : 0; 152 size_t Length = Input.size(); 153 154 std::string Output; 155 Output.reserve(2 * Length); 156 for (size_t i = 0; i < Length; ++i) { 157 const unsigned char c = Input[i]; 158 Output.push_back(LUT[c >> 4] | Offset); 159 Output.push_back(LUT[c & 15] | Offset); 160 } 161 return Output; 162 } 163 164 inline std::string toHex(ArrayRef<uint8_t> Input, bool LowerCase = false) { 165 return toHex(toStringRef(Input), LowerCase); 166 } 167 168 inline uint8_t hexFromNibbles(char MSB, char LSB) { 169 unsigned U1 = hexDigitValue(MSB); 170 unsigned U2 = hexDigitValue(LSB); 171 assert(U1 != -1U && U2 != -1U); 172 173 return static_cast<uint8_t>((U1 << 4) | U2); 174 } 175 176 /// Convert hexadecimal string \p Input to its binary representation. 177 /// The return string is half the size of \p Input. 178 inline std::string fromHex(StringRef Input) { 179 if (Input.empty()) 180 return std::string(); 181 182 std::string Output; 183 Output.reserve((Input.size() + 1) / 2); 184 if (Input.size() % 2 == 1) { 185 Output.push_back(hexFromNibbles('0', Input.front())); 186 Input = Input.drop_front(); 187 } 188 189 assert(Input.size() % 2 == 0); 190 while (!Input.empty()) { 191 uint8_t Hex = hexFromNibbles(Input[0], Input[1]); 192 Output.push_back(Hex); 193 Input = Input.drop_front(2); 194 } 195 return Output; 196 } 197 198 /// Convert the string \p S to an integer of the specified type using 199 /// the radix \p Base. If \p Base is 0, auto-detects the radix. 200 /// Returns true if the number was successfully converted, false otherwise. 201 template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) { 202 return !S.getAsInteger(Base, Num); 203 } 204 205 namespace detail { 206 template <typename N> 207 inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) { 208 SmallString<32> Storage; 209 StringRef S = T.toNullTerminatedStringRef(Storage); 210 char *End; 211 N Temp = StrTo(S.data(), &End); 212 if (*End != '\0') 213 return false; 214 Num = Temp; 215 return true; 216 } 217 } 218 219 inline bool to_float(const Twine &T, float &Num) { 220 return detail::to_float(T, Num, strtof); 221 } 222 223 inline bool to_float(const Twine &T, double &Num) { 224 return detail::to_float(T, Num, strtod); 225 } 226 227 inline bool to_float(const Twine &T, long double &Num) { 228 return detail::to_float(T, Num, strtold); 229 } 230 231 inline std::string utostr(uint64_t X, bool isNeg = false) { 232 char Buffer[21]; 233 char *BufPtr = std::end(Buffer); 234 235 if (X == 0) *--BufPtr = '0'; // Handle special case... 236 237 while (X) { 238 *--BufPtr = '0' + char(X % 10); 239 X /= 10; 240 } 241 242 if (isNeg) *--BufPtr = '-'; // Add negative sign... 243 return std::string(BufPtr, std::end(Buffer)); 244 } 245 246 inline std::string itostr(int64_t X) { 247 if (X < 0) 248 return utostr(-static_cast<uint64_t>(X), true); 249 else 250 return utostr(static_cast<uint64_t>(X)); 251 } 252 253 /// StrInStrNoCase - Portable version of strcasestr. Locates the first 254 /// occurrence of string 's1' in string 's2', ignoring case. Returns 255 /// the offset of s2 in s1 or npos if s2 cannot be found. 256 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2); 257 258 /// getToken - This function extracts one token from source, ignoring any 259 /// leading characters that appear in the Delimiters string, and ending the 260 /// token at any of the characters that appear in the Delimiters string. If 261 /// there are no tokens in the source string, an empty string is returned. 262 /// The function returns a pair containing the extracted token and the 263 /// remaining tail string. 264 std::pair<StringRef, StringRef> getToken(StringRef Source, 265 StringRef Delimiters = " \t\n\v\f\r"); 266 267 /// SplitString - Split up the specified string according to the specified 268 /// delimiters, appending the result fragments to the output list. 269 void SplitString(StringRef Source, 270 SmallVectorImpl<StringRef> &OutFragments, 271 StringRef Delimiters = " \t\n\v\f\r"); 272 273 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th). 274 inline StringRef getOrdinalSuffix(unsigned Val) { 275 // It is critically important that we do this perfectly for 276 // user-written sequences with over 100 elements. 277 switch (Val % 100) { 278 case 11: 279 case 12: 280 case 13: 281 return "th"; 282 default: 283 switch (Val % 10) { 284 case 1: return "st"; 285 case 2: return "nd"; 286 case 3: return "rd"; 287 default: return "th"; 288 } 289 } 290 } 291 292 /// Print each character of the specified string, escaping it if it is not 293 /// printable or if it is an escape char. 294 void printEscapedString(StringRef Name, raw_ostream &Out); 295 296 /// Print each character of the specified string, escaping HTML special 297 /// characters. 298 void printHTMLEscaped(StringRef String, raw_ostream &Out); 299 300 /// printLowerCase - Print each character as lowercase if it is uppercase. 301 void printLowerCase(StringRef String, raw_ostream &Out); 302 303 /// Converts a string from camel-case to snake-case by replacing all uppercase 304 /// letters with '_' followed by the letter in lowercase, except if the 305 /// uppercase letter is the first character of the string. 306 std::string convertToSnakeFromCamelCase(StringRef input); 307 308 /// Converts a string from snake-case to camel-case by replacing all occurrences 309 /// of '_' followed by a lowercase letter with the letter in uppercase. 310 /// Optionally allow capitalization of the first letter (if it is a lowercase 311 /// letter) 312 std::string convertToCamelFromSnakeCase(StringRef input, 313 bool capitalizeFirst = false); 314 315 namespace detail { 316 317 template <typename IteratorT> 318 inline std::string join_impl(IteratorT Begin, IteratorT End, 319 StringRef Separator, std::input_iterator_tag) { 320 std::string S; 321 if (Begin == End) 322 return S; 323 324 S += (*Begin); 325 while (++Begin != End) { 326 S += Separator; 327 S += (*Begin); 328 } 329 return S; 330 } 331 332 template <typename IteratorT> 333 inline std::string join_impl(IteratorT Begin, IteratorT End, 334 StringRef Separator, std::forward_iterator_tag) { 335 std::string S; 336 if (Begin == End) 337 return S; 338 339 size_t Len = (std::distance(Begin, End) - 1) * Separator.size(); 340 for (IteratorT I = Begin; I != End; ++I) 341 Len += (*Begin).size(); 342 S.reserve(Len); 343 S += (*Begin); 344 while (++Begin != End) { 345 S += Separator; 346 S += (*Begin); 347 } 348 return S; 349 } 350 351 template <typename Sep> 352 inline void join_items_impl(std::string &Result, Sep Separator) {} 353 354 template <typename Sep, typename Arg> 355 inline void join_items_impl(std::string &Result, Sep Separator, 356 const Arg &Item) { 357 Result += Item; 358 } 359 360 template <typename Sep, typename Arg1, typename... Args> 361 inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1, 362 Args &&... Items) { 363 Result += A1; 364 Result += Separator; 365 join_items_impl(Result, Separator, std::forward<Args>(Items)...); 366 } 367 368 inline size_t join_one_item_size(char) { return 1; } 369 inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; } 370 371 template <typename T> inline size_t join_one_item_size(const T &Str) { 372 return Str.size(); 373 } 374 375 inline size_t join_items_size() { return 0; } 376 377 template <typename A1> inline size_t join_items_size(const A1 &A) { 378 return join_one_item_size(A); 379 } 380 template <typename A1, typename... Args> 381 inline size_t join_items_size(const A1 &A, Args &&... Items) { 382 return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...); 383 } 384 385 } // end namespace detail 386 387 /// Joins the strings in the range [Begin, End), adding Separator between 388 /// the elements. 389 template <typename IteratorT> 390 inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) { 391 using tag = typename std::iterator_traits<IteratorT>::iterator_category; 392 return detail::join_impl(Begin, End, Separator, tag()); 393 } 394 395 /// Joins the strings in the range [R.begin(), R.end()), adding Separator 396 /// between the elements. 397 template <typename Range> 398 inline std::string join(Range &&R, StringRef Separator) { 399 return join(R.begin(), R.end(), Separator); 400 } 401 402 /// Joins the strings in the parameter pack \p Items, adding \p Separator 403 /// between the elements. All arguments must be implicitly convertible to 404 /// std::string, or there should be an overload of std::string::operator+=() 405 /// that accepts the argument explicitly. 406 template <typename Sep, typename... Args> 407 inline std::string join_items(Sep Separator, Args &&... Items) { 408 std::string Result; 409 if (sizeof...(Items) == 0) 410 return Result; 411 412 size_t NS = detail::join_one_item_size(Separator); 413 size_t NI = detail::join_items_size(std::forward<Args>(Items)...); 414 Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1); 415 detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...); 416 return Result; 417 } 418 419 } // end namespace llvm 420 421 #endif // LLVM_ADT_STRINGEXTRAS_H 422