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