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]] 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 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 [[nodiscard]] bool startswith(StringRef Prefix) const {
262 return starts_with(Prefix);
263 }
264
265 /// Check if this string starts with the given \p Prefix, ignoring case.
266 [[nodiscard]] bool starts_with_insensitive(StringRef Prefix) const;
267 [[nodiscard]] bool startswith_insensitive(StringRef Prefix) const {
268 return starts_with_insensitive(Prefix);
269 }
270
271 /// Check if this string ends with the given \p Suffix.
272 [[nodiscard]] bool ends_with(StringRef Suffix) const {
273 return Length >= Suffix.Length &&
274 compareMemory(Lhs: end() - Suffix.Length, Rhs: Suffix.Data, Length: Suffix.Length) ==
275 0;
276 }
277 [[nodiscard]] bool endswith(StringRef Suffix) const {
278 return ends_with(Suffix);
279 }
280
281 /// Check if this string ends with the given \p Suffix, ignoring case.
282 [[nodiscard]] bool ends_with_insensitive(StringRef Suffix) const;
283 [[nodiscard]] bool endswith_insensitive(StringRef Suffix) const {
284 return ends_with_insensitive(Suffix);
285 }
286
287 /// @}
288 /// @name String Searching
289 /// @{
290
291 /// Search for the first character \p C in the string.
292 ///
293 /// \returns The index of the first occurrence of \p C, or npos if not
294 /// found.
295 [[nodiscard]] size_t find(char C, size_t From = 0) const {
296 return std::string_view(*this).find(c: C, pos: From);
297 }
298
299 /// Search for the first character \p C in the string, ignoring case.
300 ///
301 /// \returns The index of the first occurrence of \p C, or npos if not
302 /// found.
303 [[nodiscard]] size_t find_insensitive(char C, size_t From = 0) const;
304
305 /// Search for the first character satisfying the predicate \p F
306 ///
307 /// \returns The index of the first character satisfying \p F starting from
308 /// \p From, or npos if not found.
309 [[nodiscard]] size_t find_if(function_ref<bool(char)> F,
310 size_t From = 0) const {
311 StringRef S = drop_front(N: From);
312 while (!S.empty()) {
313 if (F(S.front()))
314 return size() - S.size();
315 S = S.drop_front();
316 }
317 return npos;
318 }
319
320 /// Search for the first character not satisfying the predicate \p F
321 ///
322 /// \returns The index of the first character not satisfying \p F starting
323 /// from \p From, or npos if not found.
324 [[nodiscard]] size_t find_if_not(function_ref<bool(char)> F,
325 size_t From = 0) const {
326 return find_if(F: [F](char c) { return !F(c); }, From);
327 }
328
329 /// Search for the first string \p Str in the string.
330 ///
331 /// \returns The index of the first occurrence of \p Str, or npos if not
332 /// found.
333 [[nodiscard]] size_t find(StringRef Str, size_t From = 0) const;
334
335 /// Search for the first string \p Str in the string, ignoring case.
336 ///
337 /// \returns The index of the first occurrence of \p Str, or npos if not
338 /// found.
339 [[nodiscard]] size_t find_insensitive(StringRef Str, size_t From = 0) const;
340
341 /// Search for the last character \p C in the string.
342 ///
343 /// \returns The index of the last occurrence of \p C, or npos if not
344 /// found.
345 [[nodiscard]] size_t rfind(char C, size_t From = npos) const {
346 size_t I = std::min(a: From, b: Length);
347 while (I) {
348 --I;
349 if (Data[I] == C)
350 return I;
351 }
352 return npos;
353 }
354
355 /// Search for the last character \p C in the string, ignoring case.
356 ///
357 /// \returns The index of the last occurrence of \p C, or npos if not
358 /// found.
359 [[nodiscard]] size_t rfind_insensitive(char C, size_t From = npos) const;
360
361 /// Search for the last string \p Str in the string.
362 ///
363 /// \returns The index of the last occurrence of \p Str, or npos if not
364 /// found.
365 [[nodiscard]] size_t rfind(StringRef Str) const;
366
367 /// Search for the last string \p Str in the string, ignoring case.
368 ///
369 /// \returns The index of the last occurrence of \p Str, or npos if not
370 /// found.
371 [[nodiscard]] size_t rfind_insensitive(StringRef Str) const;
372
373 /// Find the first character in the string that is \p C, or npos if not
374 /// found. Same as find.
375 [[nodiscard]] size_t find_first_of(char C, size_t From = 0) const {
376 return find(C, From);
377 }
378
379 /// Find the first character in the string that is in \p Chars, or npos if
380 /// not found.
381 ///
382 /// Complexity: O(size() + Chars.size())
383 [[nodiscard]] size_t find_first_of(StringRef Chars, size_t From = 0) const;
384
385 /// Find the first character in the string that is not \p C or npos if not
386 /// found.
387 [[nodiscard]] size_t find_first_not_of(char C, size_t From = 0) const;
388
389 /// Find the first character in the string that is not in the string
390 /// \p Chars, or npos if not found.
391 ///
392 /// Complexity: O(size() + Chars.size())
393 [[nodiscard]] size_t find_first_not_of(StringRef Chars,
394 size_t From = 0) const;
395
396 /// Find the last character in the string that is \p C, or npos if not
397 /// found.
398 [[nodiscard]] size_t find_last_of(char C, size_t From = npos) const {
399 return rfind(C, From);
400 }
401
402 /// Find the last character in the string that is in \p C, or npos if not
403 /// found.
404 ///
405 /// Complexity: O(size() + Chars.size())
406 [[nodiscard]] size_t find_last_of(StringRef Chars,
407 size_t From = npos) const;
408
409 /// Find the last character in the string that is not \p C, or npos if not
410 /// found.
411 [[nodiscard]] size_t find_last_not_of(char C, size_t From = npos) const;
412
413 /// Find the last character in the string that is not in \p Chars, or
414 /// npos if not found.
415 ///
416 /// Complexity: O(size() + Chars.size())
417 [[nodiscard]] size_t find_last_not_of(StringRef Chars,
418 size_t From = npos) const;
419
420 /// Return true if the given string is a substring of *this, and false
421 /// otherwise.
422 [[nodiscard]] bool contains(StringRef Other) const {
423 return find(Str: Other) != npos;
424 }
425
426 /// Return true if the given character is contained in *this, and false
427 /// otherwise.
428 [[nodiscard]] bool contains(char C) const {
429 return find_first_of(C) != npos;
430 }
431
432 /// Return true if the given string is a substring of *this, and false
433 /// otherwise.
434 [[nodiscard]] bool contains_insensitive(StringRef Other) const {
435 return find_insensitive(Str: Other) != npos;
436 }
437
438 /// Return true if the given character is contained in *this, and false
439 /// otherwise.
440 [[nodiscard]] bool contains_insensitive(char C) const {
441 return find_insensitive(C) != npos;
442 }
443
444 /// @}
445 /// @name Helpful Algorithms
446 /// @{
447
448 /// Return the number of occurrences of \p C in the string.
449 [[nodiscard]] size_t count(char C) const {
450 size_t Count = 0;
451 for (size_t I = 0; I != Length; ++I)
452 if (Data[I] == C)
453 ++Count;
454 return Count;
455 }
456
457 /// Return the number of non-overlapped occurrences of \p Str in
458 /// the string.
459 size_t count(StringRef Str) const;
460
461 /// Parse the current string as an integer of the specified radix. If
462 /// \p Radix is specified as zero, this does radix autosensing using
463 /// extended C rules: 0 is octal, 0x is hex, 0b is binary.
464 ///
465 /// If the string is invalid or if only a subset of the string is valid,
466 /// this returns true to signify the error. The string is considered
467 /// erroneous if empty or if it overflows T.
468 template <typename T> bool getAsInteger(unsigned Radix, T &Result) const {
469 if constexpr (std::numeric_limits<T>::is_signed) {
470 long long LLVal;
471 if (getAsSignedInteger(Str: *this, Radix, Result&: LLVal) ||
472 static_cast<T>(LLVal) != LLVal)
473 return true;
474 Result = LLVal;
475 } else {
476 unsigned long long ULLVal;
477 // The additional cast to unsigned long long is required to avoid the
478 // Visual C++ warning C4805: '!=' : unsafe mix of type 'bool' and type
479 // 'unsigned __int64' when instantiating getAsInteger with T = bool.
480 if (getAsUnsignedInteger(Str: *this, Radix, Result&: ULLVal) ||
481 static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
482 return true;
483 Result = ULLVal;
484 }
485 return false;
486 }
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 does not begin with a number of the specified radix,
493 /// this returns true to signify the error. The string is considered
494 /// erroneous if empty or if it overflows T.
495 /// The portion of the string representing the discovered numeric value
496 /// is removed from the beginning of the string.
497 template <typename T> bool consumeInteger(unsigned Radix, T &Result) {
498 if constexpr (std::numeric_limits<T>::is_signed) {
499 long long LLVal;
500 if (consumeSignedInteger(Str&: *this, Radix, Result&: LLVal) ||
501 static_cast<long long>(static_cast<T>(LLVal)) != LLVal)
502 return true;
503 Result = LLVal;
504 } else {
505 unsigned long long ULLVal;
506 if (consumeUnsignedInteger(Str&: *this, Radix, Result&: ULLVal) ||
507 static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
508 return true;
509 Result = ULLVal;
510 }
511 return false;
512 }
513
514 /// Parse the current string as an integer of the specified \p Radix, or of
515 /// an autosensed radix if the \p Radix given is 0. The current value in
516 /// \p Result is discarded, and the storage is changed to be wide enough to
517 /// store the parsed integer.
518 ///
519 /// \returns true if the string does not solely consist of a valid
520 /// non-empty number in the appropriate base.
521 ///
522 /// APInt::fromString is superficially similar but assumes the
523 /// string is well-formed in the given radix.
524 bool getAsInteger(unsigned Radix, APInt &Result) const;
525
526 /// Parse the current string as an IEEE double-precision floating
527 /// point value. The string must be a well-formed double.
528 ///
529 /// If \p AllowInexact is false, the function will fail if the string
530 /// cannot be represented exactly. Otherwise, the function only fails
531 /// in case of an overflow or underflow, or an invalid floating point
532 /// representation.
533 bool getAsDouble(double &Result, bool AllowInexact = true) const;
534
535 /// @}
536 /// @name String Operations
537 /// @{
538
539 // Convert the given ASCII string to lowercase.
540 [[nodiscard]] std::string lower() const;
541
542 /// Convert the given ASCII string to uppercase.
543 [[nodiscard]] std::string upper() const;
544
545 /// @}
546 /// @name Substring Operations
547 /// @{
548
549 /// Return a reference to the substring from [Start, Start + N).
550 ///
551 /// \param Start The index of the starting character in the substring; if
552 /// the index is npos or greater than the length of the string then the
553 /// empty substring will be returned.
554 ///
555 /// \param N The number of characters to included in the substring. If N
556 /// exceeds the number of characters remaining in the string, the string
557 /// suffix (starting with \p Start) will be returned.
558 [[nodiscard]] constexpr StringRef substr(size_t Start,
559 size_t N = npos) const {
560 Start = std::min(a: Start, b: Length);
561 return StringRef(Data + Start, std::min(a: N, b: Length - Start));
562 }
563
564 /// Return a StringRef equal to 'this' but with only the first \p N
565 /// elements remaining. If \p N is greater than the length of the
566 /// string, the entire string is returned.
567 [[nodiscard]] StringRef take_front(size_t N = 1) const {
568 if (N >= size())
569 return *this;
570 return drop_back(N: size() - N);
571 }
572
573 /// Return a StringRef equal to 'this' but with only the last \p N
574 /// elements remaining. If \p N is greater than the length of the
575 /// string, the entire string is returned.
576 [[nodiscard]] StringRef take_back(size_t N = 1) const {
577 if (N >= size())
578 return *this;
579 return drop_front(N: size() - N);
580 }
581
582 /// Return the longest prefix of 'this' such that every character
583 /// in the prefix satisfies the given predicate.
584 [[nodiscard]] StringRef take_while(function_ref<bool(char)> F) const {
585 return substr(Start: 0, N: find_if_not(F));
586 }
587
588 /// Return the longest prefix of 'this' such that no character in
589 /// the prefix satisfies the given predicate.
590 [[nodiscard]] StringRef take_until(function_ref<bool(char)> F) const {
591 return substr(Start: 0, N: find_if(F));
592 }
593
594 /// Return a StringRef equal to 'this' but with the first \p N elements
595 /// dropped.
596 [[nodiscard]] StringRef drop_front(size_t N = 1) const {
597 assert(size() >= N && "Dropping more elements than exist");
598 return substr(Start: N);
599 }
600
601 /// Return a StringRef equal to 'this' but with the last \p N elements
602 /// dropped.
603 [[nodiscard]] StringRef drop_back(size_t N = 1) const {
604 assert(size() >= N && "Dropping more elements than exist");
605 return substr(Start: 0, N: size()-N);
606 }
607
608 /// Return a StringRef equal to 'this', but with all characters satisfying
609 /// the given predicate dropped from the beginning of the string.
610 [[nodiscard]] StringRef drop_while(function_ref<bool(char)> F) const {
611 return substr(Start: find_if_not(F));
612 }
613
614 /// Return a StringRef equal to 'this', but with all characters not
615 /// satisfying the given predicate dropped from the beginning of the string.
616 [[nodiscard]] StringRef drop_until(function_ref<bool(char)> F) const {
617 return substr(Start: find_if(F));
618 }
619
620 /// Returns true if this StringRef has the given prefix and removes that
621 /// prefix.
622 bool consume_front(StringRef Prefix) {
623 if (!starts_with(Prefix))
624 return false;
625
626 *this = substr(Start: Prefix.size());
627 return true;
628 }
629
630 /// Returns true if this StringRef has the given prefix, ignoring case,
631 /// and removes that prefix.
632 bool consume_front_insensitive(StringRef Prefix) {
633 if (!startswith_insensitive(Prefix))
634 return false;
635
636 *this = substr(Start: Prefix.size());
637 return true;
638 }
639
640 /// Returns true if this StringRef has the given suffix and removes that
641 /// suffix.
642 bool consume_back(StringRef Suffix) {
643 if (!ends_with(Suffix))
644 return false;
645
646 *this = substr(Start: 0, N: size() - Suffix.size());
647 return true;
648 }
649
650 /// Returns true if this StringRef has the given suffix, ignoring case,
651 /// and removes that suffix.
652 bool consume_back_insensitive(StringRef Suffix) {
653 if (!endswith_insensitive(Suffix))
654 return false;
655
656 *this = substr(Start: 0, N: size() - Suffix.size());
657 return true;
658 }
659
660 /// Return a reference to the substring from [Start, End).
661 ///
662 /// \param Start The index of the starting character in the substring; if
663 /// the index is npos or greater than the length of the string then the
664 /// empty substring will be returned.
665 ///
666 /// \param End The index following the last character to include in the
667 /// substring. If this is npos or exceeds the number of characters
668 /// remaining in the string, the string suffix (starting with \p Start)
669 /// will be returned. If this is less than \p Start, an empty string will
670 /// be returned.
671 [[nodiscard]] StringRef slice(size_t Start, size_t End) const {
672 Start = std::min(a: Start, b: Length);
673 End = std::clamp(val: End, lo: Start, hi: Length);
674 return StringRef(Data + Start, End - Start);
675 }
676
677 /// Split into two substrings around the first occurrence of a separator
678 /// character.
679 ///
680 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
681 /// such that (*this == LHS + Separator + RHS) is true and RHS is
682 /// maximal. If \p Separator is not in the string, then the result is a
683 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
684 ///
685 /// \param Separator The character to split on.
686 /// \returns The split substrings.
687 [[nodiscard]] std::pair<StringRef, StringRef> split(char Separator) const {
688 return split(Separator: StringRef(&Separator, 1));
689 }
690
691 /// Split into two substrings around the first occurrence of a separator
692 /// string.
693 ///
694 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
695 /// such that (*this == LHS + Separator + RHS) is true and RHS is
696 /// maximal. If \p Separator is not in the string, then the result is a
697 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
698 ///
699 /// \param Separator - The string to split on.
700 /// \return - The split substrings.
701 [[nodiscard]] std::pair<StringRef, StringRef>
702 split(StringRef Separator) const {
703 size_t Idx = find(Str: Separator);
704 if (Idx == npos)
705 return std::make_pair(x: *this, y: StringRef());
706 return std::make_pair(x: slice(Start: 0, End: Idx), y: slice(Start: Idx + Separator.size(), End: npos));
707 }
708
709 /// Split into two substrings around the last occurrence of a separator
710 /// string.
711 ///
712 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
713 /// such that (*this == LHS + Separator + RHS) is true and RHS is
714 /// minimal. If \p Separator is not in the string, then the result is a
715 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
716 ///
717 /// \param Separator - The string to split on.
718 /// \return - The split substrings.
719 [[nodiscard]] std::pair<StringRef, StringRef>
720 rsplit(StringRef Separator) const {
721 size_t Idx = rfind(Str: Separator);
722 if (Idx == npos)
723 return std::make_pair(x: *this, y: StringRef());
724 return std::make_pair(x: slice(Start: 0, End: Idx), y: slice(Start: Idx + Separator.size(), End: npos));
725 }
726
727 /// Split into substrings around the occurrences of a separator string.
728 ///
729 /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
730 /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
731 /// elements are added to A.
732 /// If \p KeepEmpty is false, empty strings are not added to \p A. They
733 /// still count when considering \p MaxSplit
734 /// An useful invariant is that
735 /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
736 ///
737 /// \param A - Where to put the substrings.
738 /// \param Separator - The string to split on.
739 /// \param MaxSplit - The maximum number of times the string is split.
740 /// \param KeepEmpty - True if empty substring should be added.
741 void split(SmallVectorImpl<StringRef> &A,
742 StringRef Separator, int MaxSplit = -1,
743 bool KeepEmpty = true) const;
744
745 /// Split into substrings around the occurrences of a separator character.
746 ///
747 /// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
748 /// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
749 /// elements are added to A.
750 /// If \p KeepEmpty is false, empty strings are not added to \p A. They
751 /// still count when considering \p MaxSplit
752 /// An useful invariant is that
753 /// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
754 ///
755 /// \param A - Where to put the substrings.
756 /// \param Separator - The string to split on.
757 /// \param MaxSplit - The maximum number of times the string is split.
758 /// \param KeepEmpty - True if empty substring should be added.
759 void split(SmallVectorImpl<StringRef> &A, char Separator, int MaxSplit = -1,
760 bool KeepEmpty = true) const;
761
762 /// Split into two substrings around the last occurrence of a separator
763 /// character.
764 ///
765 /// If \p Separator is in the string, then the result is a pair (LHS, RHS)
766 /// such that (*this == LHS + Separator + RHS) is true and RHS is
767 /// minimal. If \p Separator is not in the string, then the result is a
768 /// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
769 ///
770 /// \param Separator - The character to split on.
771 /// \return - The split substrings.
772 [[nodiscard]] std::pair<StringRef, StringRef> rsplit(char Separator) const {
773 return rsplit(Separator: StringRef(&Separator, 1));
774 }
775
776 /// Return string with consecutive \p Char characters starting from the
777 /// the left removed.
778 [[nodiscard]] StringRef ltrim(char Char) const {
779 return drop_front(N: std::min(a: Length, b: find_first_not_of(C: Char)));
780 }
781
782 /// Return string with consecutive characters in \p Chars starting from
783 /// the left removed.
784 [[nodiscard]] StringRef ltrim(StringRef Chars = " \t\n\v\f\r") const {
785 return drop_front(N: std::min(a: Length, b: find_first_not_of(Chars)));
786 }
787
788 /// Return string with consecutive \p Char characters starting from the
789 /// right removed.
790 [[nodiscard]] StringRef rtrim(char Char) const {
791 return drop_back(N: Length - std::min(a: Length, b: find_last_not_of(C: Char) + 1));
792 }
793
794 /// Return string with consecutive characters in \p Chars starting from
795 /// the right removed.
796 [[nodiscard]] StringRef rtrim(StringRef Chars = " \t\n\v\f\r") const {
797 return drop_back(N: Length - std::min(a: Length, b: find_last_not_of(Chars) + 1));
798 }
799
800 /// Return string with consecutive \p Char characters starting from the
801 /// left and right removed.
802 [[nodiscard]] StringRef trim(char Char) const {
803 return ltrim(Char).rtrim(Char);
804 }
805
806 /// Return string with consecutive characters in \p Chars starting from
807 /// the left and right removed.
808 [[nodiscard]] StringRef trim(StringRef Chars = " \t\n\v\f\r") const {
809 return ltrim(Chars).rtrim(Chars);
810 }
811
812 /// Detect the line ending style of the string.
813 ///
814 /// If the string contains a line ending, return the line ending character
815 /// sequence that is detected. Otherwise return '\n' for unix line endings.
816 ///
817 /// \return - The line ending character sequence.
818 [[nodiscard]] StringRef detectEOL() const {
819 size_t Pos = find(C: '\r');
820 if (Pos == npos) {
821 // If there is no carriage return, assume unix
822 return "\n";
823 }
824 if (Pos + 1 < Length && Data[Pos + 1] == '\n')
825 return "\r\n"; // Windows
826 if (Pos > 0 && Data[Pos - 1] == '\n')
827 return "\n\r"; // You monster!
828 return "\r"; // Classic Mac
829 }
830 /// @}
831 };
832
833 /// A wrapper around a string literal that serves as a proxy for constructing
834 /// global tables of StringRefs with the length computed at compile time.
835 /// In order to avoid the invocation of a global constructor, StringLiteral
836 /// should *only* be used in a constexpr context, as such:
837 ///
838 /// constexpr StringLiteral S("test");
839 ///
840 class StringLiteral : public StringRef {
841 private:
842 constexpr StringLiteral(const char *Str, size_t N) : StringRef(Str, N) {
843 }
844
845 public:
846 template <size_t N>
847 constexpr StringLiteral(const char (&Str)[N])
848#if defined(__clang__) && __has_attribute(enable_if)
849#pragma clang diagnostic push
850#pragma clang diagnostic ignored "-Wgcc-compat"
851 __attribute((enable_if(__builtin_strlen(Str) == N - 1,
852 "invalid string literal")))
853#pragma clang diagnostic pop
854#endif
855 : StringRef(Str, N - 1) {
856 }
857
858 // Explicit construction for strings like "foo\0bar".
859 template <size_t N>
860 static constexpr StringLiteral withInnerNUL(const char (&Str)[N]) {
861 return StringLiteral(Str, N - 1);
862 }
863 };
864
865 /// @name StringRef Comparison Operators
866 /// @{
867
868 inline bool operator==(StringRef LHS, StringRef RHS) {
869 return LHS.equals(RHS);
870 }
871
872 inline bool operator!=(StringRef LHS, StringRef RHS) { return !(LHS == RHS); }
873
874 inline bool operator<(StringRef LHS, StringRef RHS) {
875 return LHS.compare(RHS) < 0;
876 }
877
878 inline bool operator<=(StringRef LHS, StringRef RHS) {
879 return LHS.compare(RHS) <= 0;
880 }
881
882 inline bool operator>(StringRef LHS, StringRef RHS) {
883 return LHS.compare(RHS) > 0;
884 }
885
886 inline bool operator>=(StringRef LHS, StringRef RHS) {
887 return LHS.compare(RHS) >= 0;
888 }
889
890 inline std::string &operator+=(std::string &buffer, StringRef string) {
891 return buffer.append(s: string.data(), n: string.size());
892 }
893
894 /// @}
895
896 /// Compute a hash_code for a StringRef.
897 [[nodiscard]] hash_code hash_value(StringRef S);
898
899 // Provide DenseMapInfo for StringRefs.
900 template <> struct DenseMapInfo<StringRef, void> {
901 static inline StringRef getEmptyKey() {
902 return StringRef(
903 reinterpret_cast<const char *>(~static_cast<uintptr_t>(0)), 0);
904 }
905
906 static inline StringRef getTombstoneKey() {
907 return StringRef(
908 reinterpret_cast<const char *>(~static_cast<uintptr_t>(1)), 0);
909 }
910
911 static unsigned getHashValue(StringRef Val);
912
913 static bool isEqual(StringRef LHS, StringRef RHS) {
914 if (RHS.data() == getEmptyKey().data())
915 return LHS.data() == getEmptyKey().data();
916 if (RHS.data() == getTombstoneKey().data())
917 return LHS.data() == getTombstoneKey().data();
918 return LHS == RHS;
919 }
920 };
921
922} // end namespace llvm
923
924#endif // LLVM_ADT_STRINGREF_H
925

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