1//===- StringRef.h - Constant String Reference Wrapper ----------*- 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#ifndef LLVM_ADT_STRINGREF_H
10#define LLVM_ADT_STRINGREF_H
11
12#include "llvm/ADT/DenseMapInfo.h"
13#include "llvm/ADT/STLFunctionalExtras.h"
14#include "llvm/ADT/iterator_range.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 <string_view>
23#include <type_traits>
24#include <utility>
25
26namespace llvm {
27
28 class APInt;
29 class hash_code;
30 template <typename T> class SmallVectorImpl;
31 class StringRef;
32
33 /// Helper functions for StringRef::getAsInteger.
34 bool getAsUnsignedInteger(StringRef Str, unsigned Radix,
35 unsigned long long &Result);
36
37 bool getAsSignedInteger(StringRef Str, unsigned Radix, long long &Result);
38
39 bool consumeUnsignedInteger(StringRef &Str, unsigned Radix,
40 unsigned long long &Result);
41 bool consumeSignedInteger(StringRef &Str, unsigned Radix, long long &Result);
42
43 /// StringRef - Represent a constant reference to a string, i.e. a character
44 /// array and a length, which need not be null terminated.
45 ///
46 /// This class does not own the string data, it is expected to be used in
47 /// situations where the character data resides in some other buffer, whose
48 /// lifetime extends past that of the StringRef. For this reason, it is not in
49 /// general safe to store a StringRef.
50 class LLVM_GSL_POINTER StringRef {
51 public:
52 static constexpr size_t npos = ~size_t(0);
53
54 using iterator = const char *;
55 using const_iterator = const char *;
56 using size_type = size_t;
57
58 private:
59 /// The start of the string, in an external buffer.
60 const char *Data = nullptr;
61
62 /// The length of the string.
63 size_t Length = 0;
64
65 // Workaround memcmp issue with null pointers (undefined behavior)
66 // 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(s1: Lhs,s2: Rhs,n: 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.
84 /*implicit*/ constexpr StringRef(const char *Str)
85 : Data(Str), Length(Str ?
86 // GCC 7 doesn't have constexpr char_traits. Fall back to __builtin_strlen.
87#if defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE < 8
88 __builtin_strlen(Str)
89#else
90 std::char_traits<char>::length(s: Str)
91#endif
92 : 0) {
93 }
94
95 /// Construct a string ref from a pointer and length.
96 /*implicit*/ constexpr StringRef(const char *data, size_t length)
97 : Data(data), Length(length) {}
98
99 /// Construct a string ref from an std::string.
100 /*implicit*/ StringRef(const std::string &Str)
101 : Data(Str.data()), Length(Str.length()) {}
102
103 /// Construct a string ref from an std::string_view.
104 /*implicit*/ constexpr StringRef(std::string_view Str)
105 : Data(Str.data()), Length(Str.size()) {}
106
107 /// @}
108 /// @name Iterators
109 /// @{
110
111 iterator begin() const { return Data; }
112
113 iterator end() const { return Data + Length; }
114
115 const unsigned char *bytes_begin() const {
116 return reinterpret_cast<const unsigned char *>(begin());
117 }
118 const unsigned char *bytes_end() const {
119 return reinterpret_cast<const unsigned char *>(end());
120 }
121 iterator_range<const unsigned char *> bytes() const {
122 return make_range(x: bytes_begin(), y: bytes_end());
123 }
124
125 /// @}
126 /// @name String Operations
127 /// @{
128
129 /// data - Get a pointer to the start of the string (which may not be null
130 /// terminated).
131 [[nodiscard]] constexpr const char *data() const { return Data; }
132
133 /// empty - Check if the string is empty.
134 [[nodiscard]] constexpr bool empty() const { return Length == 0; }
135
136 /// size - Get the string size.
137 [[nodiscard]] constexpr size_t size() const { return Length; }
138
139 /// front - Get the first character in the string.
140 [[nodiscard]] char front() const {
141 assert(!empty());
142 return Data[0];
143 }
144
145 /// back - Get the last character in the string.
146 [[nodiscard]] char back() const {
147 assert(!empty());
148 return Data[Length-1];
149 }
150
151 // copy - Allocate copy in Allocator and return StringRef to it.
152 template <typename Allocator>
153 [[nodiscard]] StringRef copy(Allocator &A) const {
154 // Don't request a length 0 copy from the allocator.
155 if (empty())
156 return StringRef();
157 char *S = A.template Allocate<char>(Length);
158 std::copy(begin(), end(), S);
159 return StringRef(S, Length);
160 }
161
162 /// equals - Check for string equality, this is more efficient than
163 /// compare() when the relative ordering of inequal strings isn't needed.
164 [[nodiscard]] bool equals(StringRef RHS) const {
165 return (Length == RHS.Length &&
166 compareMemory(Lhs: Data, Rhs: RHS.Data, Length: RHS.Length) == 0);
167 }
168
169 /// Check for string equality, ignoring case.
170 [[nodiscard]] bool equals_insensitive(StringRef RHS) const {
171 return Length == RHS.Length && compare_insensitive(RHS) == 0;
172 }
173
174 /// compare - Compare two strings; the result is negative, zero, or positive
175 /// if this string is lexicographically less than, equal to, or greater than
176 /// the \p RHS.
177 [[nodiscard]] int compare(StringRef RHS) const {
178 // Check the prefix for a mismatch.
179 if (int Res = compareMemory(Lhs: Data, Rhs: RHS.Data, Length: std::min(a: Length, b: RHS.Length)))
180 return Res < 0 ? -1 : 1;
181
182 // Otherwise the prefixes match, so we only need to check the lengths.
183 if (Length == RHS.Length)
184 return 0;
185 return Length < RHS.Length ? -1 : 1;
186 }
187
188 /// Compare two strings, ignoring case.
189 [[nodiscard]] int compare_insensitive(StringRef RHS) const;
190
191 /// compare_numeric - Compare two strings, treating sequences of digits as
192 /// numbers.
193 [[nodiscard]] int compare_numeric(StringRef RHS) const;
194
195 /// Determine the edit distance between this string and another
196 /// string.
197 ///
198 /// \param Other the string to compare this string against.
199 ///
200 /// \param AllowReplacements whether to allow character
201 /// replacements (change one character into another) as a single
202 /// operation, rather than as two operations (an insertion and a
203 /// removal).
204 ///
205 /// \param MaxEditDistance If non-zero, the maximum edit distance that
206 /// this routine is allowed to compute. If the edit distance will exceed
207 /// that maximum, returns \c MaxEditDistance+1.
208 ///
209 /// \returns the minimum number of character insertions, removals,
210 /// or (if \p AllowReplacements is \c true) replacements needed to
211 /// transform one of the given strings into the other. If zero,
212 /// the strings are identical.
213 [[nodiscard]] unsigned edit_distance(StringRef Other,
214 bool AllowReplacements = true,
215 unsigned MaxEditDistance = 0) const;
216
217 [[nodiscard]] unsigned
218 edit_distance_insensitive(StringRef Other, bool AllowReplacements = true,
219 unsigned MaxEditDistance = 0) const;
220
221 /// str - Get the contents as an std::string.
222 [[nodiscard]] std::string str() const {
223 if (!Data) return std::string();
224 return std::string(Data, Length);
225 }
226
227 /// @}
228 /// @name Operator Overloads
229 /// @{
230
231 [[nodiscard]] char operator[](size_t Index) const {
232 assert(Index < Length && "Invalid index!");
233 return Data[Index];
234 }
235
236 /// Disallow accidental assignment from a temporary std::string.
237 ///
238 /// The declaration here is extra complicated so that `stringRef = {}`
239 /// and `stringRef = "abc"` continue to select the move assignment operator.
240 template <typename T>
241 std::enable_if_t<std::is_same<T, std::string>::value, StringRef> &
242 operator=(T &&Str) = delete;
243
244 /// @}
245 /// @name Type Conversions
246 /// @{
247
248 constexpr operator std::string_view() const {
249 return std::string_view(data(), size());
250 }
251
252 /// @}
253 /// @name String Predicates
254 /// @{
255
256 /// Check if this string starts with the given \p Prefix.
257 [[nodiscard]] bool starts_with(StringRef Prefix) const {
258 return Length >= Prefix.Length &&
259 compareMemory(Lhs: Data, Rhs: Prefix.Data, Length: Prefix.Length) == 0;
260 }
261
262 /// Check if this string starts with the given \p Prefix, ignoring case.
263 [[nodiscard]] bool starts_with_insensitive(StringRef Prefix) const;
264
265 /// Check if this string ends with the given \p Suffix.
266 [[nodiscard]] bool ends_with(StringRef Suffix) const {
267 return Length >= Suffix.Length &&
268 compareMemory(Lhs: end() - Suffix.Length, Rhs: Suffix.Data, Length: Suffix.Length) ==
269 0;
270 }
271
272 /// Check if this string ends with the given \p Suffix, ignoring case.
273 [[nodiscard]] bool ends_with_insensitive(StringRef Suffix) const;
274
275 /// @}
276 /// @name String Searching
277 /// @{
278
279 /// Search for the first character \p C in the string.
280 ///
281 /// \returns The index of the first occurrence of \p C, or npos if not
282 /// found.
283 [[nodiscard]] size_t find(char C, size_t From = 0) const {
284 return std::string_view(*this).find(c: C, pos: From);
285 }
286
287 /// Search for the first character \p C in the string, ignoring case.
288 ///
289 /// \returns The index of the first occurrence of \p C, or npos if not
290 /// found.
291 [[nodiscard]] size_t find_insensitive(char C, size_t From = 0) const;
292
293 /// Search for the first character satisfying the predicate \p F
294 ///
295 /// \returns The index of the first character satisfying \p F starting from
296 /// \p From, or npos if not found.
297 [[nodiscard]] size_t find_if(function_ref<bool(char)> F,
298 size_t From = 0) const {
299 StringRef S = drop_front(N: From);
300 while (!S.empty()) {
301 if (F(S.front()))
302 return size() - S.size();
303 S = S.drop_front();
304 }
305 return npos;
306 }
307
308 /// Search for the first character not satisfying the predicate \p F
309 ///
310 /// \returns The index of the first character not satisfying \p F starting
311 /// from \p From, or npos if not found.
312 [[nodiscard]] size_t find_if_not(function_ref<bool(char)> F,
313 size_t From = 0) const {
314 return find_if(F: [F](char c) { return !F(c); }, From);
315 }
316
317 /// Search for the first string \p Str in the string.
318 ///
319 /// \returns The index of the first occurrence of \p Str, or npos if not
320 /// found.
321 [[nodiscard]] size_t find(StringRef Str, size_t From = 0) const;
322
323 /// Search for the first string \p Str in the string, ignoring case.
324 ///
325 /// \returns The index of the first occurrence of \p Str, or npos if not
326 /// found.
327 [[nodiscard]] size_t find_insensitive(StringRef Str, size_t From = 0) const;
328
329 /// Search for the last character \p C in the string.
330 ///
331 /// \returns The index of the last occurrence of \p C, or npos if not
332 /// found.
333 [[nodiscard]] size_t rfind(char C, size_t From = npos) const {
334 size_t I = std::min(a: From, b: Length);
335 while (I) {
336 --I;
337 if (Data[I] == C)
338 return I;
339 }
340 return npos;
341 }
342
343 /// Search for the last character \p C in the string, ignoring case.
344 ///
345 /// \returns The index of the last occurrence of \p C, or npos if not
346 /// found.
347 [[nodiscard]] size_t rfind_insensitive(char C, size_t From = npos) const;
348
349 /// Search for the last string \p Str in the string.
350 ///
351 /// \returns The index of the last occurrence of \p Str, or npos if not
352 /// found.
353 [[nodiscard]] size_t rfind(StringRef Str) const;
354
355 /// Search for the last string \p Str in the string, ignoring case.
356 ///
357 /// \returns The index of the last occurrence of \p Str, or npos if not
358 /// found.
359 [[nodiscard]] size_t rfind_insensitive(StringRef Str) const;
360
361 /// Find the first character in the string that is \p C, or npos if not
362 /// found. Same as find.
363 [[nodiscard]] size_t find_first_of(char C, size_t From = 0) const {
364 return find(C, From);
365 }
366
367 /// Find the first character in the string that is in \p Chars, or npos if
368 /// not found.
369 ///
370 /// Complexity: O(size() + Chars.size())
371 [[nodiscard]] size_t find_first_of(StringRef Chars, size_t From = 0) const;
372
373 /// Find the first character in the string that is not \p C or npos if not
374 /// found.
375 [[nodiscard]] size_t find_first_not_of(char C, size_t From = 0) const;
376
377 /// Find the first character in the string that is not in the string
378 /// \p Chars, or npos if not found.
379 ///
380 /// Complexity: O(size() + Chars.size())
381 [[nodiscard]] size_t find_first_not_of(StringRef Chars,
382 size_t From = 0) const;
383
384 /// Find the last character in the string that is \p C, or npos if not
385 /// found.
386 [[nodiscard]] size_t find_last_of(char C, size_t From = npos) const {
387 return rfind(C, From);
388 }
389
390 /// Find the last character in the string that is in \p C, or npos if not
391 /// found.
392 ///
393 /// Complexity: O(size() + Chars.size())
394 [[nodiscard]] size_t find_last_of(StringRef Chars,
395 size_t From = npos) const;
396
397 /// Find the last character in the string that is not \p C, or npos if not
398 /// found.
399 [[nodiscard]] size_t find_last_not_of(char C, size_t From = npos) const;
400
401 /// Find the last character in the string that is not in \p Chars, or
402 /// npos if not found.
403 ///
404 /// Complexity: O(size() + Chars.size())
405 [[nodiscard]] size_t find_last_not_of(StringRef Chars,
406 size_t From = npos) const;
407
408 /// Return true if the given string is a substring of *this, and false
409 /// otherwise.
410 [[nodiscard]] bool contains(StringRef Other) const {
411 return find(Str: Other) != npos;
412 }
413
414 /// Return true if the given character is contained in *this, and false
415 /// otherwise.
416 [[nodiscard]] bool contains(char C) const {
417 return find_first_of(C) != npos;
418 }
419
420 /// Return true if the given string is a substring of *this, and false
421 /// otherwise.
422 [[nodiscard]] bool contains_insensitive(StringRef Other) const {
423 return find_insensitive(Str: Other) != npos;
424 }
425
426 /// Return true if the given character is contained in *this, and false
427 /// otherwise.
428 [[nodiscard]] bool contains_insensitive(char C) const {
429 return find_insensitive(C) != npos;
430 }
431
432 /// @}
433 /// @name Helpful Algorithms
434 /// @{
435
436 /// Return the number of occurrences of \p C in the string.
437 [[nodiscard]] size_t count(char C) const {
438 size_t Count = 0;
439 for (size_t I = 0; I != Length; ++I)
440 if (Data[I] == C)
441 ++Count;
442 return Count;
443 }
444
445 /// Return the number of non-overlapped occurrences of \p Str in
446 /// the string.
447 size_t count(StringRef Str) const;
448
449 /// Parse the current string as an integer of the specified radix. If
450 /// \p Radix is specified as zero, this does radix autosensing using
451 /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
452 ///
453 /// If the string is invalid or if only a subset of the string is valid,
454 /// this returns true to signify the error. The string is considered
455 /// erroneous if empty or if it overflows T.
456 template <typename T> bool getAsInteger(unsigned Radix, T &Result) const {
457 if constexpr (std::numeric_limits<T>::is_signed) {
458 long long LLVal;
459 if (getAsSignedInteger(Str: *this, Radix, Result&: LLVal) ||
460 static_cast<T>(LLVal) != LLVal)
461 return true;
462 Result = LLVal;
463 } else {
464 unsigned long long ULLVal;
465 // The additional cast to unsigned long long is required to avoid the
466 // Visual C++ warning C4805: '!=' : unsafe mix of type 'bool' and type
467 // 'unsigned __int64' when instantiating getAsInteger with T = bool.
468 if (getAsUnsignedInteger(Str: *this, Radix, Result&: ULLVal) ||
469 static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
470 return true;
471 Result = ULLVal;
472 }
473 return false;
474 }
475
476 /// Parse the current string as an integer of the specified radix. If
477 /// \p Radix is specified as zero, this does radix autosensing using
478 /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
479 ///
480 /// If the string does not begin with a number of the specified radix,
481 /// this returns true to signify the error. The string is considered
482 /// erroneous if empty or if it overflows T.
483 /// The portion of the string representing the discovered numeric value
484 /// is removed from the beginning of the string.
485 template <typename T> bool consumeInteger(unsigned Radix, T &Result) {
486 if constexpr (std::numeric_limits<T>::is_signed) {
487 long long LLVal;
488 if (consumeSignedInteger(Str&: *this, Radix, Result&: LLVal) ||
489 static_cast<long long>(static_cast<T>(LLVal)) != LLVal)
490 return true;
491 Result = LLVal;
492 } else {
493 unsigned long long ULLVal;
494 if (consumeUnsignedInteger(Str&: *this, Radix, Result&: ULLVal) ||
495 static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
496 return true;
497 Result = ULLVal;
498 }
499 return false;
500 }
501
502 /// Parse the current string as an integer of the specified \p Radix, or of
503 /// an autosensed radix if the \p Radix given is 0. The current value in
504 /// \p Result is discarded, and the storage is changed to be wide enough to
505 /// store the parsed integer.
506 ///
507 /// \returns true if the string does not solely consist of a valid
508 /// non-empty number in the appropriate base.
509 ///
510 /// APInt::fromString is superficially similar but assumes the
511 /// string is well-formed in the given radix.
512 bool getAsInteger(unsigned Radix, APInt &Result) const;
513
514 /// Parse the current string as an integer of the specified \p Radix. If
515 /// \p Radix is specified as zero, this does radix autosensing using
516 /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
517 ///
518 /// If the string does not begin with a number of the specified radix,
519 /// this returns true to signify the error. The string is considered
520 /// erroneous if empty.
521 /// The portion of the string representing the discovered numeric value
522 /// is removed from the beginning of the string.
523 bool consumeInteger(unsigned Radix, APInt &Result);
524
525 /// Parse the current string as an IEEE double-precision floating
526 /// point value. The string must be a well-formed double.
527 ///
528 /// If \p AllowInexact is false, the function will fail if the string
529 /// cannot be represented exactly. Otherwise, the function only fails
530 /// in case of an overflow or underflow, or an invalid floating point
531 /// representation.
532 bool getAsDouble(double &Result, bool AllowInexact = true) const;
533
534 /// @}
535 /// @name String Operations
536 /// @{
537
538 // Convert the given ASCII string to lowercase.
539 [[nodiscard]] std::string lower() const;
540
541 /// Convert the given ASCII string to uppercase.
542 [[nodiscard]] std::string upper() const;
543
544 /// @}
545 /// @name Substring Operations
546 /// @{
547
548 /// Return a reference to the substring from [Start, Start + N).
549 ///
550 /// \param Start The index of the starting character in the substring; if
551 /// the index is npos or greater than the length of the string then the
552 /// empty substring will be returned.
553 ///
554 /// \param N The number of characters to included in the substring. If N
555 /// exceeds the number of characters remaining in the string, the string
556 /// suffix (starting with \p Start) will be returned.
557 [[nodiscard]] constexpr StringRef substr(size_t Start,
558 size_t N = npos) const {
559 Start = std::min(a: Start, b: Length);
560 return StringRef(Data + Start, std::min(a: N, b: Length - Start));
561 }
562
563 /// Return a StringRef equal to 'this' but with only the first \p N
564 /// elements remaining. If \p N is greater than the length of the
565 /// string, the entire string is returned.
566 [[nodiscard]] StringRef take_front(size_t N = 1) const {
567 if (N >= size())
568 return *this;
569 return drop_back(N: size() - N);
570 }
571
572 /// Return a StringRef equal to 'this' but with only the last \p N
573 /// elements remaining. If \p N is greater than the length of the
574 /// string, the entire string is returned.
575 [[nodiscard]] StringRef take_back(size_t N = 1) const {
576 if (N >= size())
577 return *this;
578 return drop_front(N: size() - N);
579 }
580
581 /// Return the longest prefix of 'this' such that every character
582 /// in the prefix satisfies the given predicate.
583 [[nodiscard]] StringRef take_while(function_ref<bool(char)> F) const {
584 return substr(Start: 0, N: find_if_not(F));
585 }
586
587 /// Return the longest prefix of 'this' such that no character in
588 /// the prefix satisfies the given predicate.
589 [[nodiscard]] StringRef take_until(function_ref<bool(char)> F) const {
590 return substr(Start: 0, N: find_if(F));
591 }
592
593 /// Return a StringRef equal to 'this' but with the first \p N elements
594 /// dropped.
595 [[nodiscard]] StringRef drop_front(size_t N = 1) const {
596 assert(size() >= N && "Dropping more elements than exist");
597 return substr(Start: N);
598 }
599
600 /// Return a StringRef equal to 'this' but with the last \p N elements
601 /// dropped.
602 [[nodiscard]] StringRef drop_back(size_t N = 1) const {
603 assert(size() >= N && "Dropping more elements than exist");
604 return substr(Start: 0, N: size()-N);
605 }
606
607 /// Return a StringRef equal to 'this', but with all characters satisfying
608 /// the given predicate dropped from the beginning of the string.
609 [[nodiscard]] StringRef drop_while(function_ref<bool(char)> F) const {
610 return substr(Start: find_if_not(F));
611 }
612
613 /// Return a StringRef equal to 'this', but with all characters not
614 /// satisfying the given predicate dropped from the beginning of the string.
615 [[nodiscard]] StringRef drop_until(function_ref<bool(char)> F) const {
616 return substr(Start: find_if(F));
617 }
618
619 /// Returns true if this StringRef has the given prefix and removes that
620 /// prefix.
621 bool consume_front(StringRef Prefix) {
622 if (!starts_with(Prefix))
623 return false;
624
625 *this = substr(Start: Prefix.size());
626 return true;
627 }
628
629 /// Returns true if this StringRef has the given prefix, ignoring case,
630 /// and removes that prefix.
631 bool consume_front_insensitive(StringRef Prefix) {
632 if (!starts_with_insensitive(Prefix))
633 return false;
634
635 *this = substr(Start: Prefix.size());
636 return true;
637 }
638
639 /// Returns true if this StringRef has the given suffix and removes that
640 /// suffix.
641 bool consume_back(StringRef Suffix) {
642 if (!ends_with(Suffix))
643 return false;
644
645 *this = substr(Start: 0, N: size() - Suffix.size());
646 return true;
647 }
648
649 /// Returns true if this StringRef has the given suffix, ignoring case,
650 /// and removes that suffix.
651 bool consume_back_insensitive(StringRef Suffix) {
652 if (!ends_with_insensitive(Suffix))
653 return false;
654
655 *this = substr(Start: 0, N: size() - Suffix.size());
656 return true;
657 }
658
659 /// Return a reference to the substring from [Start, End).
660 ///
661 /// \param Start The index of the starting character in the substring; if
662 /// the index is npos or greater than the length of the string then the
663 /// empty substring will be returned.
664 ///
665 /// \param End The index following the last character to include in the
666 /// substring. If this is npos or exceeds the number of characters
667 /// remaining in the string, the string suffix (starting with \p Start)
668 /// will be returned. If this is less than \p Start, an empty string will
669 /// be returned.
670 [[nodiscard]] StringRef slice(size_t Start, size_t End) const {
671 Start = std::min(a: Start, b: Length);
672 End = std::clamp(val: End, lo: Start, hi: Length);
673 return StringRef(Data + Start, End - Start);
674 }
675
676 /// Split into two substrings around the first occurrence of a separator
677 /// character.
678 ///
679 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
680 /// such that (*this == LHS + Separator + RHS) is true and RHS is
681 /// maximal. If \p Separator is not in the string, then the result is a
682 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
683 ///
684 /// \param Separator The character to split on.
685 /// \returns The split substrings.
686 [[nodiscard]] std::pair<StringRef, StringRef> split(char Separator) const {
687 return split(Separator: StringRef(&Separator, 1));
688 }
689
690 /// Split into two substrings around the first occurrence of a separator
691 /// string.
692 ///
693 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
694 /// such that (*this == LHS + Separator + RHS) is true and RHS is
695 /// maximal. If \p Separator is not in the string, then the result is a
696 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
697 ///
698 /// \param Separator - The string to split on.
699 /// \return - The split substrings.
700 [[nodiscard]] std::pair<StringRef, StringRef>
701 split(StringRef Separator) const {
702 size_t Idx = find(Str: Separator);
703 if (Idx == npos)
704 return std::make_pair(x: *this, y: StringRef());
705 return std::make_pair(x: slice(Start: 0, End: Idx), y: slice(Start: Idx + Separator.size(), End: npos));
706 }
707
708 /// Split into two substrings around the last occurrence of a separator
709 /// string.
710 ///
711 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
712 /// such that (*this == LHS + Separator + RHS) is true and RHS is
713 /// minimal. If \p Separator is not in the string, then the result is a
714 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
715 ///
716 /// \param Separator - The string to split on.
717 /// \return - The split substrings.
718 [[nodiscard]] std::pair<StringRef, StringRef>
719 rsplit(StringRef Separator) const {
720 size_t Idx = rfind(Str: Separator);
721 if (Idx == npos)
722 return std::make_pair(x: *this, y: StringRef());
723 return std::make_pair(x: slice(Start: 0, End: Idx), y: slice(Start: Idx + Separator.size(), End: npos));
724 }
725
726 /// Split into substrings around the occurrences of a separator string.
727 ///
728 /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
729 /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
730 /// elements are added to A.
731 /// If \p KeepEmpty is false, empty strings are not added to \p A. They
732 /// still count when considering \p MaxSplit
733 /// An useful invariant is that
734 /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
735 ///
736 /// \param A - Where to put the substrings.
737 /// \param Separator - The string to split on.
738 /// \param MaxSplit - The maximum number of times the string is split.
739 /// \param KeepEmpty - True if empty substring should be added.
740 void split(SmallVectorImpl<StringRef> &A,
741 StringRef Separator, int MaxSplit = -1,
742 bool KeepEmpty = true) const;
743
744 /// Split into substrings around the occurrences of a separator character.
745 ///
746 /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
747 /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
748 /// elements are added to A.
749 /// If \p KeepEmpty is false, empty strings are not added to \p A. They
750 /// still count when considering \p MaxSplit
751 /// An useful invariant is that
752 /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
753 ///
754 /// \param A - Where to put the substrings.
755 /// \param Separator - The string to split on.
756 /// \param MaxSplit - The maximum number of times the string is split.
757 /// \param KeepEmpty - True if empty substring should be added.
758 void split(SmallVectorImpl<StringRef> &A, char Separator, int MaxSplit = -1,
759 bool KeepEmpty = true) const;
760
761 /// Split into two substrings around the last occurrence of a separator
762 /// character.
763 ///
764 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
765 /// such that (*this == LHS + Separator + RHS) is true and RHS is
766 /// minimal. If \p Separator is not in the string, then the result is a
767 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
768 ///
769 /// \param Separator - The character to split on.
770 /// \return - The split substrings.
771 [[nodiscard]] std::pair<StringRef, StringRef> rsplit(char Separator) const {
772 return rsplit(Separator: StringRef(&Separator, 1));
773 }
774
775 /// Return string with consecutive \p Char characters starting from the
776 /// the left removed.
777 [[nodiscard]] StringRef ltrim(char Char) const {
778 return drop_front(N: std::min(a: Length, b: find_first_not_of(C: Char)));
779 }
780
781 /// Return string with consecutive characters in \p Chars starting from
782 /// the left removed.
783 [[nodiscard]] StringRef ltrim(StringRef Chars = " \t\n\v\f\r") const {
784 return drop_front(N: std::min(a: Length, b: find_first_not_of(Chars)));
785 }
786
787 /// Return string with consecutive \p Char characters starting from the
788 /// right removed.
789 [[nodiscard]] StringRef rtrim(char Char) const {
790 return drop_back(N: Length - std::min(a: Length, b: find_last_not_of(C: Char) + 1));
791 }
792
793 /// Return string with consecutive characters in \p Chars starting from
794 /// the right removed.
795 [[nodiscard]] StringRef rtrim(StringRef Chars = " \t\n\v\f\r") const {
796 return drop_back(N: Length - std::min(a: Length, b: find_last_not_of(Chars) + 1));
797 }
798
799 /// Return string with consecutive \p Char characters starting from the
800 /// left and right removed.
801 [[nodiscard]] StringRef trim(char Char) const {
802 return ltrim(Char).rtrim(Char);
803 }
804
805 /// Return string with consecutive characters in \p Chars starting from
806 /// the left and right removed.
807 [[nodiscard]] StringRef trim(StringRef Chars = " \t\n\v\f\r") const {
808 return ltrim(Chars).rtrim(Chars);
809 }
810
811 /// Detect the line ending style of the string.
812 ///
813 /// If the string contains a line ending, return the line ending character
814 /// sequence that is detected. Otherwise return '\n' for unix line endings.
815 ///
816 /// \return - The line ending character sequence.
817 [[nodiscard]] StringRef detectEOL() const {
818 size_t Pos = find(C: '\r');
819 if (Pos == npos) {
820 // If there is no carriage return, assume unix
821 return "\n";
822 }
823 if (Pos + 1 < Length && Data[Pos + 1] == '\n')
824 return "\r\n"; // Windows
825 if (Pos > 0 && Data[Pos - 1] == '\n')
826 return "\n\r"; // You monster!
827 return "\r"; // Classic Mac
828 }
829 /// @}
830 };
831
832 /// A wrapper around a string literal that serves as a proxy for constructing
833 /// global tables of StringRefs with the length computed at compile time.
834 /// In order to avoid the invocation of a global constructor, StringLiteral
835 /// should *only* be used in a constexpr context, as such:
836 ///
837 /// constexpr StringLiteral S("test");
838 ///
839 class StringLiteral : public StringRef {
840 private:
841 constexpr StringLiteral(const char *Str, size_t N) : StringRef(Str, N) {
842 }
843
844 public:
845 template <size_t N>
846 constexpr StringLiteral(const char (&Str)[N])
847#if defined(__clang__) && __has_attribute(enable_if)
848#pragma clang diagnostic push
849#pragma clang diagnostic ignored "-Wgcc-compat"
850 __attribute((enable_if(__builtin_strlen(Str) == N - 1,
851 "invalid string literal")))
852#pragma clang diagnostic pop
853#endif
854 : StringRef(Str, N - 1) {
855 }
856
857 // Explicit construction for strings like "foo\0bar".
858 template <size_t N>
859 static constexpr StringLiteral withInnerNUL(const char (&Str)[N]) {
860 return StringLiteral(Str, N - 1);
861 }
862 };
863
864 /// @name StringRef Comparison Operators
865 /// @{
866
867 inline bool operator==(StringRef LHS, StringRef RHS) {
868 return LHS.equals(RHS);
869 }
870
871 inline bool operator!=(StringRef LHS, StringRef RHS) { return !(LHS == RHS); }
872
873 inline bool operator<(StringRef LHS, StringRef RHS) {
874 return LHS.compare(RHS) < 0;
875 }
876
877 inline bool operator<=(StringRef LHS, StringRef RHS) {
878 return LHS.compare(RHS) <= 0;
879 }
880
881 inline bool operator>(StringRef LHS, StringRef RHS) {
882 return LHS.compare(RHS) > 0;
883 }
884
885 inline bool operator>=(StringRef LHS, StringRef RHS) {
886 return LHS.compare(RHS) >= 0;
887 }
888
889 inline std::string &operator+=(std::string &buffer, StringRef string) {
890 return buffer.append(s: string.data(), n: string.size());
891 }
892
893 /// @}
894
895 /// Compute a hash_code for a StringRef.
896 [[nodiscard]] hash_code hash_value(StringRef S);
897
898 // Provide DenseMapInfo for StringRefs.
899 template <> struct DenseMapInfo<StringRef, void> {
900 static inline StringRef getEmptyKey() {
901 return StringRef(
902 reinterpret_cast<const char *>(~static_cast<uintptr_t>(0)), 0);
903 }
904
905 static inline StringRef getTombstoneKey() {
906 return StringRef(
907 reinterpret_cast<const char *>(~static_cast<uintptr_t>(1)), 0);
908 }
909
910 static unsigned getHashValue(StringRef Val);
911
912 static bool isEqual(StringRef LHS, StringRef RHS) {
913 if (RHS.data() == getEmptyKey().data())
914 return LHS.data() == getEmptyKey().data();
915 if (RHS.data() == getTombstoneKey().data())
916 return LHS.data() == getTombstoneKey().data();
917 return LHS == RHS;
918 }
919 };
920
921} // end namespace llvm
922
923#endif // LLVM_ADT_STRINGREF_H
924

source code of llvm/include/llvm/ADT/StringRef.h