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StringRef.h
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1 //===- StringRef.h - Constant String Reference Wrapper ----------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_ADT_STRINGREF_H
11 #define LLVM_ADT_STRINGREF_H
12 
13 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/Support/Compiler.h"
16 #include <algorithm>
17 #include <cassert>
18 #include <cstddef>
19 #include <cstring>
20 #include <limits>
21 #include <string>
22 #include <type_traits>
23 #include <utility>
24 
25 namespace llvm {
26 
27  class APInt;
28  class hash_code;
29  template <typename T> class SmallVectorImpl;
30  class StringRef;
31 
32  /// Helper functions for StringRef::getAsInteger.
33  bool getAsUnsignedInteger(StringRef Str, unsigned Radix,
34  unsigned long long &Result);
35 
36  bool getAsSignedInteger(StringRef Str, unsigned Radix, long long &Result);
37 
38  bool consumeUnsignedInteger(StringRef &Str, unsigned Radix,
39  unsigned long long &Result);
40  bool consumeSignedInteger(StringRef &Str, unsigned Radix, long long &Result);
41 
42  /// StringRef - Represent a constant reference to a string, i.e. a character
43  /// array and a length, which need not be null terminated.
44  ///
45  /// This class does not own the string data, it is expected to be used in
46  /// situations where the character data resides in some other buffer, whose
47  /// lifetime extends past that of the StringRef. For this reason, it is not in
48  /// general safe to store a StringRef.
49  class StringRef {
50  public:
51  static const size_t npos = ~size_t(0);
52 
53  using iterator = const char *;
54  using const_iterator = const char *;
55  using size_type = size_t;
56 
57  private:
58  /// The start of the string, in an external buffer.
59  const char *Data = nullptr;
60 
61  /// The length of the string.
62  size_t Length = 0;
63 
64  // Workaround memcmp issue with null pointers (undefined behavior)
65  // by providing a specialized version
67  static int compareMemory(const char *Lhs, const char *Rhs, size_t Length) {
68  if (Length == 0) { return 0; }
69  return ::memcmp(Lhs,Rhs,Length);
70  }
71 
72  public:
73  /// @name Constructors
74  /// @{
75 
76  /// Construct an empty string ref.
77  /*implicit*/ StringRef() = default;
78 
79  /// Disable conversion from nullptr. This prevents things like
80  /// if (S == nullptr)
81  StringRef(std::nullptr_t) = delete;
82 
83  /// Construct a string ref from a cstring.
85  /*implicit*/ StringRef(const char *Str)
86  : Data(Str), Length(Str ? ::strlen(Str) : 0) {}
87 
88  /// Construct a string ref from a pointer and length.
90  /*implicit*/ constexpr StringRef(const char *data, size_t length)
91  : Data(data), Length(length) {}
92 
93  /// Construct a string ref from an std::string.
95  /*implicit*/ StringRef(const std::string &Str)
96  : Data(Str.data()), Length(Str.length()) {}
97 
98  static StringRef withNullAsEmpty(const char *data) {
99  return StringRef(data ? data : "");
100  }
101 
102  /// @}
103  /// @name Iterators
104  /// @{
105 
106  iterator begin() const { return Data; }
107 
108  iterator end() const { return Data + Length; }
109 
110  const unsigned char *bytes_begin() const {
111  return reinterpret_cast<const unsigned char *>(begin());
112  }
113  const unsigned char *bytes_end() const {
114  return reinterpret_cast<const unsigned char *>(end());
115  }
117  return make_range(bytes_begin(), bytes_end());
118  }
119 
120  /// @}
121  /// @name String Operations
122  /// @{
123 
124  /// data - Get a pointer to the start of the string (which may not be null
125  /// terminated).
128  const char *data() const { return Data; }
129 
130  /// empty - Check if the string is empty.
133  bool empty() const { return Length == 0; }
134 
135  /// size - Get the string size.
138  size_t size() const { return Length; }
139 
140  /// front - Get the first character in the string.
142  char front() const {
143  assert(!empty());
144  return Data[0];
145  }
146 
147  /// back - Get the last character in the string.
149  char back() const {
150  assert(!empty());
151  return Data[Length-1];
152  }
153 
154  // copy - Allocate copy in Allocator and return StringRef to it.
155  template <typename Allocator>
157  // Don't request a length 0 copy from the allocator.
158  if (empty())
159  return StringRef();
160  char *S = A.template Allocate<char>(Length);
161  std::copy(begin(), end(), S);
162  return StringRef(S, Length);
163  }
164 
165  /// equals - Check for string equality, this is more efficient than
166  /// compare() when the relative ordering of inequal strings isn't needed.
169  bool equals(StringRef RHS) const {
170  return (Length == RHS.Length &&
171  compareMemory(Data, RHS.Data, RHS.Length) == 0);
172  }
173 
174  /// equals_lower - Check for string equality, ignoring case.
176  bool equals_lower(StringRef RHS) const {
177  return Length == RHS.Length && compare_lower(RHS) == 0;
178  }
179 
180  /// compare - Compare two strings; the result is -1, 0, or 1 if this string
181  /// is lexicographically less than, equal to, or greater than the \p RHS.
184  int compare(StringRef RHS) const {
185  // Check the prefix for a mismatch.
186  if (int Res = compareMemory(Data, RHS.Data, std::min(Length, RHS.Length)))
187  return Res < 0 ? -1 : 1;
188 
189  // Otherwise the prefixes match, so we only need to check the lengths.
190  if (Length == RHS.Length)
191  return 0;
192  return Length < RHS.Length ? -1 : 1;
193  }
194 
195  /// compare_lower - Compare two strings, ignoring case.
197  int compare_lower(StringRef RHS) const;
198 
199  /// compare_numeric - Compare two strings, treating sequences of digits as
200  /// numbers.
202  int compare_numeric(StringRef RHS) const;
203 
204  /// \brief Determine the edit distance between this string and another
205  /// string.
206  ///
207  /// \param Other the string to compare this string against.
208  ///
209  /// \param AllowReplacements whether to allow character
210  /// replacements (change one character into another) as a single
211  /// operation, rather than as two operations (an insertion and a
212  /// removal).
213  ///
214  /// \param MaxEditDistance If non-zero, the maximum edit distance that
215  /// this routine is allowed to compute. If the edit distance will exceed
216  /// that maximum, returns \c MaxEditDistance+1.
217  ///
218  /// \returns the minimum number of character insertions, removals,
219  /// or (if \p AllowReplacements is \c true) replacements needed to
220  /// transform one of the given strings into the other. If zero,
221  /// the strings are identical.
223  unsigned edit_distance(StringRef Other, bool AllowReplacements = true,
224  unsigned MaxEditDistance = 0) const;
225 
226  /// str - Get the contents as an std::string.
228  std::string str() const {
229  if (!Data) return std::string();
230  return std::string(Data, Length);
231  }
232 
233  /// @}
234  /// @name Operator Overloads
235  /// @{
236 
238  char operator[](size_t Index) const {
239  assert(Index < Length && "Invalid index!");
240  return Data[Index];
241  }
242 
243  /// Disallow accidental assignment from a temporary std::string.
244  ///
245  /// The declaration here is extra complicated so that `stringRef = {}`
246  /// and `stringRef = "abc"` continue to select the move assignment operator.
247  template <typename T>
248  typename std::enable_if<std::is_same<T, std::string>::value,
249  StringRef>::type &
250  operator=(T &&Str) = delete;
251 
252  /// @}
253  /// @name Type Conversions
254  /// @{
255 
256  operator std::string() const {
257  return str();
258  }
259 
260  /// @}
261  /// @name String Predicates
262  /// @{
263 
264  /// Check if this string starts with the given \p Prefix.
268  return Length >= Prefix.Length &&
269  compareMemory(Data, Prefix.Data, Prefix.Length) == 0;
270  }
271 
272  /// Check if this string starts with the given \p Prefix, ignoring case.
274  bool startswith_lower(StringRef Prefix) const;
275 
276  /// Check if this string ends with the given \p Suffix.
279  bool endswith(StringRef Suffix) const {
280  return Length >= Suffix.Length &&
281  compareMemory(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
282  }
283 
284  /// Check if this string ends with the given \p Suffix, ignoring case.
286  bool endswith_lower(StringRef Suffix) const;
287 
288  /// @}
289  /// @name String Searching
290  /// @{
291 
292  /// Search for the first character \p C in the string.
293  ///
294  /// \returns The index of the first occurrence of \p C, or npos if not
295  /// found.
298  size_t find(char C, size_t From = 0) const {
299  size_t FindBegin = std::min(From, Length);
300  if (FindBegin < Length) { // Avoid calling memchr with nullptr.
301  // Just forward to memchr, which is faster than a hand-rolled loop.
302  if (const void *P = ::memchr(Data + FindBegin, C, Length - FindBegin))
303  return static_cast<const char *>(P) - Data;
304  }
305  return npos;
306  }
307 
308  /// Search for the first character \p C in the string, ignoring case.
309  ///
310  /// \returns The index of the first occurrence of \p C, or npos if not
311  /// found.
313  size_t find_lower(char C, size_t From = 0) const;
314 
315  /// Search for the first character satisfying the predicate \p F
316  ///
317  /// \returns The index of the first character satisfying \p F starting from
318  /// \p From, or npos if not found.
321  size_t find_if(function_ref<bool(char)> F, size_t From = 0) const {
322  StringRef S = drop_front(From);
323  while (!S.empty()) {
324  if (F(S.front()))
325  return size() - S.size();
326  S = S.drop_front();
327  }
328  return npos;
329  }
330 
331  /// Search for the first character not satisfying the predicate \p F
332  ///
333  /// \returns The index of the first character not satisfying \p F starting
334  /// from \p From, or npos if not found.
337  size_t find_if_not(function_ref<bool(char)> F, size_t From = 0) const {
338  return find_if([F](char c) { return !F(c); }, From);
339  }
340 
341  /// Search for the first string \p Str in the string.
342  ///
343  /// \returns The index of the first occurrence of \p Str, or npos if not
344  /// found.
346  size_t find(StringRef Str, size_t From = 0) const;
347 
348  /// Search for the first string \p Str in the string, ignoring case.
349  ///
350  /// \returns The index of the first occurrence of \p Str, or npos if not
351  /// found.
353  size_t find_lower(StringRef Str, size_t From = 0) const;
354 
355  /// Search for the last character \p C in the string.
356  ///
357  /// \returns The index of the last occurrence of \p C, or npos if not
358  /// found.
360  size_t rfind(char C, size_t From = npos) const {
361  From = std::min(From, Length);
362  size_t i = From;
363  while (i != 0) {
364  --i;
365  if (Data[i] == C)
366  return i;
367  }
368  return npos;
369  }
370 
371  /// Search for the last character \p C in the string, ignoring case.
372  ///
373  /// \returns The index of the last occurrence of \p C, or npos if not
374  /// found.
376  size_t rfind_lower(char C, size_t From = npos) const;
377 
378  /// Search for the last string \p Str in the string.
379  ///
380  /// \returns The index of the last occurrence of \p Str, or npos if not
381  /// found.
383  size_t rfind(StringRef Str) const;
384 
385  /// Search for the last string \p Str in the string, ignoring case.
386  ///
387  /// \returns The index of the last occurrence of \p Str, or npos if not
388  /// found.
390  size_t rfind_lower(StringRef Str) const;
391 
392  /// Find the first character in the string that is \p C, or npos if not
393  /// found. Same as find.
395  size_t find_first_of(char C, size_t From = 0) const {
396  return find(C, From);
397  }
398 
399  /// Find the first character in the string that is in \p Chars, or npos if
400  /// not found.
401  ///
402  /// Complexity: O(size() + Chars.size())
404  size_t find_first_of(StringRef Chars, size_t From = 0) const;
405 
406  /// Find the first character in the string that is not \p C or npos if not
407  /// found.
409  size_t find_first_not_of(char C, size_t From = 0) const;
410 
411  /// Find the first character in the string that is not in the string
412  /// \p Chars, or npos if not found.
413  ///
414  /// Complexity: O(size() + Chars.size())
416  size_t find_first_not_of(StringRef Chars, size_t From = 0) const;
417 
418  /// Find the last character in the string that is \p C, or npos if not
419  /// found.
421  size_t find_last_of(char C, size_t From = npos) const {
422  return rfind(C, From);
423  }
424 
425  /// Find the last character in the string that is in \p C, or npos if not
426  /// found.
427  ///
428  /// Complexity: O(size() + Chars.size())
430  size_t find_last_of(StringRef Chars, size_t From = npos) const;
431 
432  /// Find the last character in the string that is not \p C, or npos if not
433  /// found.
435  size_t find_last_not_of(char C, size_t From = npos) const;
436 
437  /// Find the last character in the string that is not in \p Chars, or
438  /// npos if not found.
439  ///
440  /// Complexity: O(size() + Chars.size())
442  size_t find_last_not_of(StringRef Chars, size_t From = npos) const;
443 
444  /// Return true if the given string is a substring of *this, and false
445  /// otherwise.
448  bool contains(StringRef Other) const { return find(Other) != npos; }
449 
450  /// Return true if the given character is contained in *this, and false
451  /// otherwise.
454  bool contains(char C) const { return find_first_of(C) != npos; }
455 
456  /// Return true if the given string is a substring of *this, and false
457  /// otherwise.
460  bool contains_lower(StringRef Other) const {
461  return find_lower(Other) != npos;
462  }
463 
464  /// Return true if the given character is contained in *this, and false
465  /// otherwise.
468  bool contains_lower(char C) const { return find_lower(C) != npos; }
469 
470  /// @}
471  /// @name Helpful Algorithms
472  /// @{
473 
474  /// Return the number of occurrences of \p C in the string.
476  size_t count(char C) const {
477  size_t Count = 0;
478  for (size_t i = 0, e = Length; i != e; ++i)
479  if (Data[i] == C)
480  ++Count;
481  return Count;
482  }
483 
484  /// Return the number of non-overlapped occurrences of \p Str in
485  /// the string.
486  size_t count(StringRef Str) const;
487 
488  /// Parse the current string as an integer of the specified radix. If
489  /// \p Radix is specified as zero, this does radix autosensing using
490  /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
491  ///
492  /// If the string is invalid or if only a subset of the string is valid,
493  /// this returns true to signify the error. The string is considered
494  /// erroneous if empty or if it overflows T.
495  template <typename T>
496  typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
497  getAsInteger(unsigned Radix, T &Result) const {
498  long long LLVal;
499  if (getAsSignedInteger(*this, Radix, LLVal) ||
500  static_cast<T>(LLVal) != LLVal)
501  return true;
502  Result = LLVal;
503  return false;
504  }
505 
506  template <typename T>
507  typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
508  getAsInteger(unsigned Radix, T &Result) const {
509  unsigned long long ULLVal;
510  // The additional cast to unsigned long long is required to avoid the
511  // Visual C++ warning C4805: '!=' : unsafe mix of type 'bool' and type
512  // 'unsigned __int64' when instantiating getAsInteger with T = bool.
513  if (getAsUnsignedInteger(*this, Radix, ULLVal) ||
514  static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
515  return true;
516  Result = ULLVal;
517  return false;
518  }
519 
520  /// Parse the current string as an integer of the specified radix. If
521  /// \p Radix is specified as zero, this does radix autosensing using
522  /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
523  ///
524  /// If the string does not begin with a number of the specified radix,
525  /// this returns true to signify the error. The string is considered
526  /// erroneous if empty or if it overflows T.
527  /// The portion of the string representing the discovered numeric value
528  /// is removed from the beginning of the string.
529  template <typename T>
530  typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
531  consumeInteger(unsigned Radix, T &Result) {
532  long long LLVal;
533  if (consumeSignedInteger(*this, Radix, LLVal) ||
534  static_cast<long long>(static_cast<T>(LLVal)) != LLVal)
535  return true;
536  Result = LLVal;
537  return false;
538  }
539 
540  template <typename T>
541  typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
542  consumeInteger(unsigned Radix, T &Result) {
543  unsigned long long ULLVal;
544  if (consumeUnsignedInteger(*this, Radix, ULLVal) ||
545  static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
546  return true;
547  Result = ULLVal;
548  return false;
549  }
550 
551  /// Parse the current string as an integer of the specified \p Radix, or of
552  /// an autosensed radix if the \p Radix given is 0. The current value in
553  /// \p Result is discarded, and the storage is changed to be wide enough to
554  /// store the parsed integer.
555  ///
556  /// \returns true if the string does not solely consist of a valid
557  /// non-empty number in the appropriate base.
558  ///
559  /// APInt::fromString is superficially similar but assumes the
560  /// string is well-formed in the given radix.
561  bool getAsInteger(unsigned Radix, APInt &Result) const;
562 
563  /// Parse the current string as an IEEE double-precision floating
564  /// point value. The string must be a well-formed double.
565  ///
566  /// If \p AllowInexact is false, the function will fail if the string
567  /// cannot be represented exactly. Otherwise, the function only fails
568  /// in case of an overflow or underflow.
569  bool getAsDouble(double &Result, bool AllowInexact = true) const;
570 
571  /// @}
572  /// @name String Operations
573  /// @{
574 
575  // Convert the given ASCII string to lowercase.
577  std::string lower() const;
578 
579  /// Convert the given ASCII string to uppercase.
581  std::string upper() const;
582 
583  /// @}
584  /// @name Substring Operations
585  /// @{
586 
587  /// Return a reference to the substring from [Start, Start + N).
588  ///
589  /// \param Start The index of the starting character in the substring; if
590  /// the index is npos or greater than the length of the string then the
591  /// empty substring will be returned.
592  ///
593  /// \param N The number of characters to included in the substring. If N
594  /// exceeds the number of characters remaining in the string, the string
595  /// suffix (starting with \p Start) will be returned.
598  StringRef substr(size_t Start, size_t N = npos) const {
599  Start = std::min(Start, Length);
600  return StringRef(Data + Start, std::min(N, Length - Start));
601  }
602 
603  /// Return a StringRef equal to 'this' but with only the first \p N
604  /// elements remaining. If \p N is greater than the length of the
605  /// string, the entire string is returned.
608  StringRef take_front(size_t N = 1) const {
609  if (N >= size())
610  return *this;
611  return drop_back(size() - N);
612  }
613 
614  /// Return a StringRef equal to 'this' but with only the last \p N
615  /// elements remaining. If \p N is greater than the length of the
616  /// string, the entire string is returned.
619  StringRef take_back(size_t N = 1) const {
620  if (N >= size())
621  return *this;
622  return drop_front(size() - N);
623  }
624 
625  /// Return the longest prefix of 'this' such that every character
626  /// in the prefix satisfies the given predicate.
629  StringRef take_while(function_ref<bool(char)> F) const {
630  return substr(0, find_if_not(F));
631  }
632 
633  /// Return the longest prefix of 'this' such that no character in
634  /// the prefix satisfies the given predicate.
637  StringRef take_until(function_ref<bool(char)> F) const {
638  return substr(0, find_if(F));
639  }
640 
641  /// Return a StringRef equal to 'this' but with the first \p N elements
642  /// dropped.
645  StringRef drop_front(size_t N = 1) const {
646  assert(size() >= N && "Dropping more elements than exist");
647  return substr(N);
648  }
649 
650  /// Return a StringRef equal to 'this' but with the last \p N elements
651  /// dropped.
654  StringRef drop_back(size_t N = 1) const {
655  assert(size() >= N && "Dropping more elements than exist");
656  return substr(0, size()-N);
657  }
658 
659  /// Return a StringRef equal to 'this', but with all characters satisfying
660  /// the given predicate dropped from the beginning of the string.
663  StringRef drop_while(function_ref<bool(char)> F) const {
664  return substr(find_if_not(F));
665  }
666 
667  /// Return a StringRef equal to 'this', but with all characters not
668  /// satisfying the given predicate dropped from the beginning of the string.
671  StringRef drop_until(function_ref<bool(char)> F) const {
672  return substr(find_if(F));
673  }
674 
675  /// Returns true if this StringRef has the given prefix and removes that
676  /// prefix.
678  bool consume_front(StringRef Prefix) {
679  if (!startswith(Prefix))
680  return false;
681 
682  *this = drop_front(Prefix.size());
683  return true;
684  }
685 
686  /// Returns true if this StringRef has the given suffix and removes that
687  /// suffix.
689  bool consume_back(StringRef Suffix) {
690  if (!endswith(Suffix))
691  return false;
692 
693  *this = drop_back(Suffix.size());
694  return true;
695  }
696 
697  /// Return a reference to the substring from [Start, End).
698  ///
699  /// \param Start The index of the starting character in the substring; if
700  /// the index is npos or greater than the length of the string then the
701  /// empty substring will be returned.
702  ///
703  /// \param End The index following the last character to include in the
704  /// substring. If this is npos or exceeds the number of characters
705  /// remaining in the string, the string suffix (starting with \p Start)
706  /// will be returned. If this is less than \p Start, an empty string will
707  /// be returned.
710  StringRef slice(size_t Start, size_t End) const {
711  Start = std::min(Start, Length);
712  End = std::min(std::max(Start, End), Length);
713  return StringRef(Data + Start, End - Start);
714  }
715 
716  /// Split into two substrings around the first occurrence of a separator
717  /// character.
718  ///
719  /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
720  /// such that (*this == LHS + Separator + RHS) is true and RHS is
721  /// maximal. If \p Separator is not in the string, then the result is a
722  /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
723  ///
724  /// \param Separator The character to split on.
725  /// \returns The split substrings.
727  std::pair<StringRef, StringRef> split(char Separator) const {
728  size_t Idx = find(Separator);
729  if (Idx == npos)
730  return std::make_pair(*this, StringRef());
731  return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
732  }
733 
734  /// Split into two substrings around the first occurrence of a separator
735  /// string.
736  ///
737  /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
738  /// such that (*this == LHS + Separator + RHS) is true and RHS is
739  /// maximal. If \p Separator is not in the string, then the result is a
740  /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
741  ///
742  /// \param Separator - The string to split on.
743  /// \return - The split substrings.
745  std::pair<StringRef, StringRef> split(StringRef Separator) const {
746  size_t Idx = find(Separator);
747  if (Idx == npos)
748  return std::make_pair(*this, StringRef());
749  return std::make_pair(slice(0, Idx), slice(Idx + Separator.size(), npos));
750  }
751 
752  /// Split into substrings around the occurrences of a separator string.
753  ///
754  /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
755  /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
756  /// elements are added to A.
757  /// If \p KeepEmpty is false, empty strings are not added to \p A. They
758  /// still count when considering \p MaxSplit
759  /// An useful invariant is that
760  /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
761  ///
762  /// \param A - Where to put the substrings.
763  /// \param Separator - The string to split on.
764  /// \param MaxSplit - The maximum number of times the string is split.
765  /// \param KeepEmpty - True if empty substring should be added.
767  StringRef Separator, int MaxSplit = -1,
768  bool KeepEmpty = true) const;
769 
770  /// Split into substrings around the occurrences of a separator character.
771  ///
772  /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
773  /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
774  /// elements are added to A.
775  /// If \p KeepEmpty is false, empty strings are not added to \p A. They
776  /// still count when considering \p MaxSplit
777  /// An useful invariant is that
778  /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
779  ///
780  /// \param A - Where to put the substrings.
781  /// \param Separator - The string to split on.
782  /// \param MaxSplit - The maximum number of times the string is split.
783  /// \param KeepEmpty - True if empty substring should be added.
784  void split(SmallVectorImpl<StringRef> &A, char Separator, int MaxSplit = -1,
785  bool KeepEmpty = true) const;
786 
787  /// Split into two substrings around the last occurrence of a separator
788  /// character.
789  ///
790  /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
791  /// such that (*this == LHS + Separator + RHS) is true and RHS is
792  /// minimal. If \p Separator is not in the string, then the result is a
793  /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
794  ///
795  /// \param Separator - The character to split on.
796  /// \return - The split substrings.
798  std::pair<StringRef, StringRef> rsplit(char Separator) const {
799  size_t Idx = rfind(Separator);
800  if (Idx == npos)
801  return std::make_pair(*this, StringRef());
802  return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
803  }
804 
805  /// Return string with consecutive \p Char characters starting from the
806  /// the left removed.
808  StringRef ltrim(char Char) const {
809  return drop_front(std::min(Length, find_first_not_of(Char)));
810  }
811 
812  /// Return string with consecutive characters in \p Chars starting from
813  /// the left removed.
815  StringRef ltrim(StringRef Chars = " \t\n\v\f\r") const {
816  return drop_front(std::min(Length, find_first_not_of(Chars)));
817  }
818 
819  /// Return string with consecutive \p Char characters starting from the
820  /// right removed.
822  StringRef rtrim(char Char) const {
823  return drop_back(Length - std::min(Length, find_last_not_of(Char) + 1));
824  }
825 
826  /// Return string with consecutive characters in \p Chars starting from
827  /// the right removed.
829  StringRef rtrim(StringRef Chars = " \t\n\v\f\r") const {
830  return drop_back(Length - std::min(Length, find_last_not_of(Chars) + 1));
831  }
832 
833  /// Return string with consecutive \p Char characters starting from the
834  /// left and right removed.
836  StringRef trim(char Char) const {
837  return ltrim(Char).rtrim(Char);
838  }
839 
840  /// Return string with consecutive characters in \p Chars starting from
841  /// the left and right removed.
843  StringRef trim(StringRef Chars = " \t\n\v\f\r") const {
844  return ltrim(Chars).rtrim(Chars);
845  }
846 
847  /// @}
848  };
849 
850  /// A wrapper around a string literal that serves as a proxy for constructing
851  /// global tables of StringRefs with the length computed at compile time.
852  /// In order to avoid the invocation of a global constructor, StringLiteral
853  /// should *only* be used in a constexpr context, as such:
854  ///
855  /// constexpr StringLiteral S("test");
856  ///
857  class StringLiteral : public StringRef {
858  public:
859  template <size_t N>
860  constexpr StringLiteral(const char (&Str)[N])
861 #if defined(__clang__) && __has_attribute(enable_if)
862 #pragma clang diagnostic push
863 #pragma clang diagnostic ignored "-Wgcc-compat"
864  __attribute((enable_if(__builtin_strlen(Str) == N - 1,
865  "invalid string literal")))
866 #pragma clang diagnostic pop
867 #endif
868  : StringRef(Str, N - 1) {
869  }
870  };
871 
872  /// @name StringRef Comparison Operators
873  /// @{
874 
876  inline bool operator==(StringRef LHS, StringRef RHS) {
877  return LHS.equals(RHS);
878  }
879 
881  inline bool operator!=(StringRef LHS, StringRef RHS) { return !(LHS == RHS); }
882 
883  inline bool operator<(StringRef LHS, StringRef RHS) {
884  return LHS.compare(RHS) == -1;
885  }
886 
887  inline bool operator<=(StringRef LHS, StringRef RHS) {
888  return LHS.compare(RHS) != 1;
889  }
890 
891  inline bool operator>(StringRef LHS, StringRef RHS) {
892  return LHS.compare(RHS) == 1;
893  }
894 
895  inline bool operator>=(StringRef LHS, StringRef RHS) {
896  return LHS.compare(RHS) != -1;
897  }
898 
899  inline std::string &operator+=(std::string &buffer, StringRef string) {
900  return buffer.append(string.data(), string.size());
901  }
902 
903  /// @}
904 
905  /// \brief Compute a hash_code for a StringRef.
908 
909  // StringRefs can be treated like a POD type.
910  template <typename T> struct isPodLike;
911  template <> struct isPodLike<StringRef> { static const bool value = true; };
912 
913 } // end namespace llvm
914 
915 #endif // LLVM_ADT_STRINGREF_H
uint64_t CallInst * C
std::string & operator+=(std::string &buffer, StringRef string)
Definition: StringRef.h:899
std::enable_if<!std::numeric_limits< T >::is_signed, bool >::type getAsInteger(unsigned Radix, T &Result) const
Definition: StringRef.h:508
static StringRef withNullAsEmpty(const char *data)
Definition: StringRef.h:98
LLVM_NODISCARD char operator[](size_t Index) const
Definition: StringRef.h:238
LLVM_NODISCARD bool startswith_lower(StringRef Prefix) const
Check if this string starts with the given Prefix, ignoring case.
Definition: StringRef.cpp:62
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
LLVM_NODISCARD std::string str() const
str - Get the contents as an std::string.
Definition: StringRef.h:228
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool contains(StringRef Other) const
Return true if the given string is a substring of *this, and false otherwise.
Definition: StringRef.h:448
const unsigned char * bytes_end() const
Definition: StringRef.h:113
LLVM_NODISCARD bool equals_lower(StringRef RHS) const
equals_lower - Check for string equality, ignoring case.
Definition: StringRef.h:176
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE size_t find_if(function_ref< bool(char)> F, size_t From=0) const
Search for the first character satisfying the predicate F.
Definition: StringRef.h:321
bool consumeUnsignedInteger(StringRef &Str, unsigned Radix, unsigned long long &Result)
Definition: StringRef.cpp:426
LLVM_NODISCARD size_t rfind(char C, size_t From=npos) const
Search for the last character C in the string.
Definition: StringRef.h:360
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
bool getAsUnsignedInteger(StringRef Str, unsigned Radix, unsigned long long &Result)
Helper functions for StringRef::getAsInteger.
Definition: StringRef.cpp:504
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE size_t size() const
size - Get the string size.
Definition: StringRef.h:138
bool operator>(int64_t V1, const APSInt &V2)
Definition: APSInt.h:327
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:87
LLVM_NODISCARD size_t find_last_of(char C, size_t From=npos) const
Find the last character in the string that is C, or npos if not found.
Definition: StringRef.h:421
F(f)
LLVM_NODISCARD bool endswith_lower(StringRef Suffix) const
Check if this string ends with the given Suffix, ignoring case.
Definition: StringRef.cpp:68
LLVM_NODISCARD StringRef ltrim(char Char) const
Return string with consecutive Char characters starting from the the left removed.
Definition: StringRef.h:808
std::enable_if<!std::numeric_limits< T >::is_signed, bool >::type consumeInteger(unsigned Radix, T &Result)
Definition: StringRef.h:542
LLVM_NODISCARD unsigned edit_distance(StringRef Other, bool AllowReplacements=true, unsigned MaxEditDistance=0) const
Determine the edit distance between this string and another string.
Definition: StringRef.cpp:110
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:128
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef take_back(size_t N=1) const
Return a StringRef equal to &#39;this&#39; but with only the last N elements remaining.
Definition: StringRef.h:619
bool operator<=(int64_t V1, const APSInt &V2)
Definition: APSInt.h:324
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool endswith(StringRef Suffix) const
Check if this string ends with the given Suffix.
Definition: StringRef.h:279
bool operator>=(int64_t V1, const APSInt &V2)
Definition: APSInt.h:325
LLVM_NODISCARD StringRef copy(Allocator &A) const
Definition: StringRef.h:156
LLVM_NODISCARD size_t count(char C) const
Return the number of occurrences of C in the string.
Definition: StringRef.h:476
LLVM_ATTRIBUTE_ALWAYS_INLINE bool consume_back(StringRef Suffix)
Returns true if this StringRef has the given suffix and removes that suffix.
Definition: StringRef.h:689
#define LLVM_ATTRIBUTE_ALWAYS_INLINE
LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do so, mark a method "always...
Definition: Compiler.h:198
iterator_range< const unsigned char * > bytes() const
Definition: StringRef.h:116
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef take_until(function_ref< bool(char)> F) const
Return the longest prefix of &#39;this&#39; such that no character in the prefix satisfies the given predicat...
Definition: StringRef.h:637
ELFYAML::ELF_STO Other
Definition: ELFYAML.cpp:720
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool startswith(StringRef Prefix) const
Check if this string starts with the given Prefix.
Definition: StringRef.h:267
LLVM_ATTRIBUTE_ALWAYS_INLINE bool consume_front(StringRef Prefix)
Returns true if this StringRef has the given prefix and removes that prefix.
Definition: StringRef.h:678
std::enable_if< std::numeric_limits< T >::is_signed, bool >::type consumeInteger(unsigned Radix, T &Result)
Parse the current string as an integer of the specified radix.
Definition: StringRef.h:531
LLVM_NODISCARD StringRef rtrim(StringRef Chars=" \\\) const
Return string with consecutive characters in Chars starting from the right removed.
Definition: StringRef.h:829
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:133
LLVM_NODISCARD std::pair< StringRef, StringRef > rsplit(char Separator) const
Split into two substrings around the last occurrence of a separator character.
Definition: StringRef.h:798
hash_code hash_value(const APFloat &Arg)
See friend declarations above.
Definition: APFloat.cpp:4425
StringRef()=default
Construct an empty string ref.
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef substr(size_t Start, size_t N=npos) const
Return a reference to the substring from [Start, Start + N).
Definition: StringRef.h:598
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool contains_lower(char C) const
Return true if the given character is contained in *this, and false otherwise.
Definition: StringRef.h:468
LLVM_ATTRIBUTE_ALWAYS_INLINE constexpr StringRef(const char *data, size_t length)
Construct a string ref from a pointer and length.
Definition: StringRef.h:90
LLVM_NODISCARD std::string upper() const
Convert the given ASCII string to uppercase.
Definition: StringRef.cpp:131
#define P(N)
A wrapper around a string literal that serves as a proxy for constructing global tables of StringRefs...
Definition: StringRef.h:857
LLVM_NODISCARD StringRef trim(char Char) const
Return string with consecutive Char characters starting from the left and right removed.
Definition: StringRef.h:836
LLVM_NODISCARD size_t find_first_not_of(char C, size_t From=0) const
Find the first character in the string that is not C or npos if not found.
Definition: StringRef.cpp:265
static const unsigned End
LLVM_NODISCARD size_t rfind_lower(char C, size_t From=npos) const
Search for the last character C in the string, ignoring case.
Definition: StringRef.cpp:208
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE int compare(StringRef RHS) const
compare - Compare two strings; the result is -1, 0, or 1 if this string is lexicographically less tha...
Definition: StringRef.h:184
LLVM_NODISCARD StringRef ltrim(StringRef Chars=" \\\) const
Return string with consecutive characters in Chars starting from the left removed.
Definition: StringRef.h:815
LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef(const std::string &Str)
Construct a string ref from an std::string.
Definition: StringRef.h:95
LLVM_NODISCARD char back() const
back - Get the last character in the string.
Definition: StringRef.h:149
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE size_t find_if_not(function_ref< bool(char)> F, size_t From=0) const
Search for the first character not satisfying the predicate F.
Definition: StringRef.h:337
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef drop_back(size_t N=1) const
Return a StringRef equal to &#39;this&#39; but with the last N elements dropped.
Definition: StringRef.h:654
std::enable_if< std::numeric_limits< T >::is_signed, bool >::type getAsInteger(unsigned Radix, T &Result) const
Parse the current string as an integer of the specified radix.
Definition: StringRef.h:497
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef take_while(function_ref< bool(char)> F) const
Return the longest prefix of &#39;this&#39; such that every character in the prefix satisfies the given predi...
Definition: StringRef.h:629
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef drop_front(size_t N=1) const
Return a StringRef equal to &#39;this&#39; but with the first N elements dropped.
Definition: StringRef.h:645
LLVM_NODISCARD int compare_lower(StringRef RHS) const
compare_lower - Compare two strings, ignoring case.
Definition: StringRef.cpp:53
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef drop_until(function_ref< bool(char)> F) const
Return a StringRef equal to &#39;this&#39;, but with all characters not satisfying the given predicate droppe...
Definition: StringRef.h:671
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
Basic Register Allocator
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool contains(char C) const
Return true if the given character is contained in *this, and false otherwise.
Definition: StringRef.h:454
isPodLike - This is a type trait that is used to determine whether a given type can be copied around ...
Definition: ArrayRef.h:530
LLVM_NODISCARD std::pair< StringRef, StringRef > split(char Separator) const
Split into two substrings around the first occurrence of a separator character.
Definition: StringRef.h:727
bool getAsDouble(double &Result, bool AllowInexact=true) const
Parse the current string as an IEEE double-precision floating point value.
Definition: StringRef.cpp:599
std::enable_if< std::is_same< T, std::string >::value, StringRef >::type & operator=(T &&Str)=delete
Disallow accidental assignment from a temporary std::string.
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef slice(size_t Start, size_t End) const
Return a reference to the substring from [Start, End).
Definition: StringRef.h:710
LLVM_NODISCARD size_t find_lower(char C, size_t From=0) const
Search for the first character C in the string, ignoring case.
Definition: StringRef.cpp:73
LLVM_NODISCARD size_t find_last_not_of(char C, size_t From=npos) const
Find the last character in the string that is not C, or npos if not found.
Definition: StringRef.cpp:306
A range adaptor for a pair of iterators.
Class for arbitrary precision integers.
Definition: APInt.h:69
An opaque object representing a hash code.
Definition: Hashing.h:72
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool equals(StringRef RHS) const
equals - Check for string equality, this is more efficient than compare() when the relative ordering ...
Definition: StringRef.h:169
iterator begin() const
Definition: StringRef.h:106
LLVM_NODISCARD int compare_numeric(StringRef RHS) const
compare_numeric - Compare two strings, treating sequences of digits as numbers.
Definition: StringRef.cpp:79
constexpr StringLiteral(const char(&Str)[N])
Definition: StringRef.h:860
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:1948
const unsigned char * bytes_begin() const
Definition: StringRef.h:110
Merge contiguous icmps into a memcmp
Definition: MergeICmps.cpp:643
static const size_t npos
Definition: StringRef.h:51
LLVM_NODISCARD StringRef trim(StringRef Chars=" \\\) const
Return string with consecutive characters in Chars starting from the left and right removed...
Definition: StringRef.h:843
LLVM_NODISCARD size_t find_first_of(char C, size_t From=0) const
Find the first character in the string that is C, or npos if not found.
Definition: StringRef.h:395
#define N
#define LLVM_NODISCARD
LLVM_NODISCARD - Warn if a type or return value is discarded.
Definition: Compiler.h:126
LLVM_NODISCARD std::string lower() const
Definition: StringRef.cpp:123
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM_NODISCARD char front() const
front - Get the first character in the string.
Definition: StringRef.h:142
bool operator<(int64_t V1, const APSInt &V2)
Definition: APSInt.h:326
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool contains_lower(StringRef Other) const
Return true if the given string is a substring of *this, and false otherwise.
Definition: StringRef.h:460
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef drop_while(function_ref< bool(char)> F) const
Return a StringRef equal to &#39;this&#39;, but with all characters satisfying the given predicate dropped fr...
Definition: StringRef.h:663
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef take_front(size_t N=1) const
Return a StringRef equal to &#39;this&#39; but with only the first N elements remaining.
Definition: StringRef.h:608
LLVM_NODISCARD StringRef rtrim(char Char) const
Return string with consecutive Char characters starting from the right removed.
Definition: StringRef.h:822
LLVM_NODISCARD std::pair< StringRef, StringRef > split(StringRef Separator) const
Split into two substrings around the first occurrence of a separator string.
Definition: StringRef.h:745
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1946
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE size_t find(char C, size_t From=0) const
Search for the first character C in the string.
Definition: StringRef.h:298
bool consumeSignedInteger(StringRef &Str, unsigned Radix, long long &Result)
Definition: StringRef.cpp:474
iterator end() const
Definition: StringRef.h:108
bool getAsSignedInteger(StringRef Str, unsigned Radix, long long &Result)
Definition: StringRef.cpp:514
LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef(const char *Str)
Construct a string ref from a cstring.
Definition: StringRef.h:85