include/llvm/ADT/StringExtras.h

   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