1//===- llvm/ADT/StringExtras.h - Useful string functions --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// This file contains some functions that are useful when dealing with strings.
11///
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_ADT_STRINGEXTRAS_H
15#define LLVM_ADT_STRINGEXTRAS_H
16
17#include "llvm/ADT/APSInt.h"
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/SmallString.h"
20#include "llvm/ADT/StringRef.h"
21#include "llvm/ADT/Twine.h"
22#include <cassert>
23#include <cstddef>
24#include <cstdint>
25#include <cstdlib>
26#include <cstring>
27#include <iterator>
28#include <string>
29#include <utility>
30
31namespace llvm {
32
33class raw_ostream;
34
35/// hexdigit - Return the hexadecimal character for the
36/// given number \p X (which should be less than 16).
37inline char hexdigit(unsigned X, bool LowerCase = false) {
38 assert(X < 16);
39 static const char LUT[] = "0123456789ABCDEF";
40 const uint8_t Offset = LowerCase ? 32 : 0;
41 return LUT[X] | Offset;
42}
43
44/// Given an array of c-style strings terminated by a null pointer, construct
45/// a vector of StringRefs representing the same strings without the terminating
46/// null string.
47inline std::vector<StringRef> toStringRefArray(const char *const *Strings) {
48 std::vector<StringRef> Result;
49 while (*Strings)
50 Result.push_back(x: *Strings++);
51 return Result;
52}
53
54/// Construct a string ref from a boolean.
55inline StringRef toStringRef(bool B) { return StringRef(B ? "true" : "false"); }
56
57/// Construct a string ref from an array ref of unsigned chars.
58inline StringRef toStringRef(ArrayRef<uint8_t> Input) {
59 return StringRef(reinterpret_cast<const char *>(Input.begin()), Input.size());
60}
61
62/// Construct a string ref from an array ref of unsigned chars.
63inline ArrayRef<uint8_t> arrayRefFromStringRef(StringRef Input) {
64 return {Input.bytes_begin(), Input.bytes_end()};
65}
66
67/// Interpret the given character \p C as a hexadecimal digit and return its
68/// value.
69///
70/// If \p C is not a valid hex digit, -1U is returned.
71inline unsigned hexDigitValue(char C) {
72 /* clang-format off */
73 static const int16_t LUT[256] = {
74 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
75 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
76 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
77 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, // '0'..'9'
78 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 'A'..'F'
79 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
80 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 'a'..'f'
81 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
82 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
83 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
84 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
85 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
86 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
87 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
88 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
89 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
90 };
91 /* clang-format on */
92 return LUT[static_cast<unsigned char>(C)];
93}
94
95/// Checks if character \p C is one of the 10 decimal digits.
96inline bool isDigit(char C) { return C >= '0' && C <= '9'; }
97
98/// Checks if character \p C is a hexadecimal numeric character.
99inline bool isHexDigit(char C) { return hexDigitValue(C) != ~0U; }
100
101/// Checks if character \p C is a valid letter as classified by "C" locale.
102inline bool isAlpha(char C) {
103 return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');
104}
105
106/// Checks whether character \p C is either a decimal digit or an uppercase or
107/// lowercase letter as classified by "C" locale.
108inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); }
109
110/// Checks whether character \p C is valid ASCII (high bit is zero).
111inline bool isASCII(char C) { return static_cast<unsigned char>(C) <= 127; }
112
113/// Checks whether all characters in S are ASCII.
114inline bool isASCII(llvm::StringRef S) {
115 for (char C : S)
116 if (LLVM_UNLIKELY(!isASCII(C)))
117 return false;
118 return true;
119}
120
121/// Checks whether character \p C is printable.
122///
123/// Locale-independent version of the C standard library isprint whose results
124/// may differ on different platforms.
125inline bool isPrint(char C) {
126 unsigned char UC = static_cast<unsigned char>(C);
127 return (0x20 <= UC) && (UC <= 0x7E);
128}
129
130/// Checks whether character \p C is whitespace in the "C" locale.
131///
132/// Locale-independent version of the C standard library isspace.
133inline bool isSpace(char C) {
134 return C == ' ' || C == '\f' || C == '\n' || C == '\r' || C == '\t' ||
135 C == '\v';
136}
137
138/// Returns the corresponding lowercase character if \p x is uppercase.
139inline char toLower(char x) {
140 if (x >= 'A' && x <= 'Z')
141 return x - 'A' + 'a';
142 return x;
143}
144
145/// Returns the corresponding uppercase character if \p x is lowercase.
146inline char toUpper(char x) {
147 if (x >= 'a' && x <= 'z')
148 return x - 'a' + 'A';
149 return x;
150}
151
152inline std::string utohexstr(uint64_t X, bool LowerCase = false,
153 unsigned Width = 0) {
154 char Buffer[17];
155 char *BufPtr = std::end(arr&: Buffer);
156
157 if (X == 0) *--BufPtr = '0';
158
159 for (unsigned i = 0; Width ? (i < Width) : X; ++i) {
160 unsigned char Mod = static_cast<unsigned char>(X) & 15;
161 *--BufPtr = hexdigit(X: Mod, LowerCase);
162 X >>= 4;
163 }
164
165 return std::string(BufPtr, std::end(arr&: Buffer));
166}
167
168/// Convert buffer \p Input to its hexadecimal representation.
169/// The returned string is double the size of \p Input.
170inline void toHex(ArrayRef<uint8_t> Input, bool LowerCase,
171 SmallVectorImpl<char> &Output) {
172 const size_t Length = Input.size();
173 Output.resize_for_overwrite(N: Length * 2);
174
175 for (size_t i = 0; i < Length; i++) {
176 const uint8_t c = Input[i];
177 Output[i * 2 ] = hexdigit(X: c >> 4, LowerCase);
178 Output[i * 2 + 1] = hexdigit(X: c & 15, LowerCase);
179 }
180}
181
182inline std::string toHex(ArrayRef<uint8_t> Input, bool LowerCase = false) {
183 SmallString<16> Output;
184 toHex(Input, LowerCase, Output);
185 return std::string(Output);
186}
187
188inline std::string toHex(StringRef Input, bool LowerCase = false) {
189 return toHex(Input: arrayRefFromStringRef(Input), LowerCase);
190}
191
192/// Store the binary representation of the two provided values, \p MSB and
193/// \p LSB, that make up the nibbles of a hexadecimal digit. If \p MSB or \p LSB
194/// do not correspond to proper nibbles of a hexadecimal digit, this method
195/// returns false. Otherwise, returns true.
196inline bool tryGetHexFromNibbles(char MSB, char LSB, uint8_t &Hex) {
197 unsigned U1 = hexDigitValue(C: MSB);
198 unsigned U2 = hexDigitValue(C: LSB);
199 if (U1 == ~0U || U2 == ~0U)
200 return false;
201
202 Hex = static_cast<uint8_t>((U1 << 4) | U2);
203 return true;
204}
205
206/// Return the binary representation of the two provided values, \p MSB and
207/// \p LSB, that make up the nibbles of a hexadecimal digit.
208inline uint8_t hexFromNibbles(char MSB, char LSB) {
209 uint8_t Hex = 0;
210 bool GotHex = tryGetHexFromNibbles(MSB, LSB, Hex);
211 (void)GotHex;
212 assert(GotHex && "MSB and/or LSB do not correspond to hex digits");
213 return Hex;
214}
215
216/// Convert hexadecimal string \p Input to its binary representation and store
217/// the result in \p Output. Returns true if the binary representation could be
218/// converted from the hexadecimal string. Returns false if \p Input contains
219/// non-hexadecimal digits. The output string is half the size of \p Input.
220inline bool tryGetFromHex(StringRef Input, std::string &Output) {
221 if (Input.empty())
222 return true;
223
224 // If the input string is not properly aligned on 2 nibbles we pad out the
225 // front with a 0 prefix; e.g. `ABC` -> `0ABC`.
226 Output.resize(n: (Input.size() + 1) / 2);
227 char *OutputPtr = const_cast<char *>(Output.data());
228 if (Input.size() % 2 == 1) {
229 uint8_t Hex = 0;
230 if (!tryGetHexFromNibbles(MSB: '0', LSB: Input.front(), Hex))
231 return false;
232 *OutputPtr++ = Hex;
233 Input = Input.drop_front();
234 }
235
236 // Convert the nibble pairs (e.g. `9C`) into bytes (0x9C).
237 // With the padding above we know the input is aligned and the output expects
238 // exactly half as many bytes as nibbles in the input.
239 size_t InputSize = Input.size();
240 assert(InputSize % 2 == 0);
241 const char *InputPtr = Input.data();
242 for (size_t OutputIndex = 0; OutputIndex < InputSize / 2; ++OutputIndex) {
243 uint8_t Hex = 0;
244 if (!tryGetHexFromNibbles(MSB: InputPtr[OutputIndex * 2 + 0], // MSB
245 LSB: InputPtr[OutputIndex * 2 + 1], // LSB
246 Hex))
247 return false;
248 OutputPtr[OutputIndex] = Hex;
249 }
250 return true;
251}
252
253/// Convert hexadecimal string \p Input to its binary representation.
254/// The return string is half the size of \p Input.
255inline std::string fromHex(StringRef Input) {
256 std::string Hex;
257 bool GotHex = tryGetFromHex(Input, Output&: Hex);
258 (void)GotHex;
259 assert(GotHex && "Input contains non hex digits");
260 return Hex;
261}
262
263/// Convert the string \p S to an integer of the specified type using
264/// the radix \p Base. If \p Base is 0, auto-detects the radix.
265/// Returns true if the number was successfully converted, false otherwise.
266template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) {
267 return !S.getAsInteger(Base, Num);
268}
269
270namespace detail {
271template <typename N>
272inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) {
273 SmallString<32> Storage;
274 StringRef S = T.toNullTerminatedStringRef(Out&: Storage);
275 char *End;
276 N Temp = StrTo(S.data(), &End);
277 if (*End != '\0')
278 return false;
279 Num = Temp;
280 return true;
281}
282}
283
284inline bool to_float(const Twine &T, float &Num) {
285 return detail::to_float(T, Num, StrTo: strtof);
286}
287
288inline bool to_float(const Twine &T, double &Num) {
289 return detail::to_float(T, Num, StrTo: strtod);
290}
291
292inline bool to_float(const Twine &T, long double &Num) {
293 return detail::to_float(T, Num, StrTo: strtold);
294}
295
296inline std::string utostr(uint64_t X, bool isNeg = false) {
297 char Buffer[21];
298 char *BufPtr = std::end(arr&: Buffer);
299
300 if (X == 0) *--BufPtr = '0'; // Handle special case...
301
302 while (X) {
303 *--BufPtr = '0' + char(X % 10);
304 X /= 10;
305 }
306
307 if (isNeg) *--BufPtr = '-'; // Add negative sign...
308 return std::string(BufPtr, std::end(arr&: Buffer));
309}
310
311inline std::string itostr(int64_t X) {
312 if (X < 0)
313 return utostr(X: static_cast<uint64_t>(1) + ~static_cast<uint64_t>(X), isNeg: true);
314 else
315 return utostr(X: static_cast<uint64_t>(X));
316}
317
318inline std::string toString(const APInt &I, unsigned Radix, bool Signed,
319 bool formatAsCLiteral = false) {
320 SmallString<40> S;
321 I.toString(Str&: S, Radix, Signed, formatAsCLiteral);
322 return std::string(S.str());
323}
324
325inline std::string toString(const APSInt &I, unsigned Radix) {
326 return toString(I, Radix, Signed: I.isSigned());
327}
328
329/// StrInStrNoCase - Portable version of strcasestr. Locates the first
330/// occurrence of string 's1' in string 's2', ignoring case. Returns
331/// the offset of s2 in s1 or npos if s2 cannot be found.
332StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
333
334/// getToken - This function extracts one token from source, ignoring any
335/// leading characters that appear in the Delimiters string, and ending the
336/// token at any of the characters that appear in the Delimiters string. If
337/// there are no tokens in the source string, an empty string is returned.
338/// The function returns a pair containing the extracted token and the
339/// remaining tail string.
340std::pair<StringRef, StringRef> getToken(StringRef Source,
341 StringRef Delimiters = " \t\n\v\f\r");
342
343/// SplitString - Split up the specified string according to the specified
344/// delimiters, appending the result fragments to the output list.
345void SplitString(StringRef Source,
346 SmallVectorImpl<StringRef> &OutFragments,
347 StringRef Delimiters = " \t\n\v\f\r");
348
349/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
350inline StringRef getOrdinalSuffix(unsigned Val) {
351 // It is critically important that we do this perfectly for
352 // user-written sequences with over 100 elements.
353 switch (Val % 100) {
354 case 11:
355 case 12:
356 case 13:
357 return "th";
358 default:
359 switch (Val % 10) {
360 case 1: return "st";
361 case 2: return "nd";
362 case 3: return "rd";
363 default: return "th";
364 }
365 }
366}
367
368/// Print each character of the specified string, escaping it if it is not
369/// printable or if it is an escape char.
370void printEscapedString(StringRef Name, raw_ostream &Out);
371
372/// Print each character of the specified string, escaping HTML special
373/// characters.
374void printHTMLEscaped(StringRef String, raw_ostream &Out);
375
376/// printLowerCase - Print each character as lowercase if it is uppercase.
377void printLowerCase(StringRef String, raw_ostream &Out);
378
379/// Converts a string from camel-case to snake-case by replacing all uppercase
380/// letters with '_' followed by the letter in lowercase, except if the
381/// uppercase letter is the first character of the string.
382std::string convertToSnakeFromCamelCase(StringRef input);
383
384/// Converts a string from snake-case to camel-case by replacing all occurrences
385/// of '_' followed by a lowercase letter with the letter in uppercase.
386/// Optionally allow capitalization of the first letter (if it is a lowercase
387/// letter)
388std::string convertToCamelFromSnakeCase(StringRef input,
389 bool capitalizeFirst = false);
390
391namespace detail {
392
393template <typename IteratorT>
394inline std::string join_impl(IteratorT Begin, IteratorT End,
395 StringRef Separator, std::input_iterator_tag) {
396 std::string S;
397 if (Begin == End)
398 return S;
399
400 S += (*Begin);
401 while (++Begin != End) {
402 S += Separator;
403 S += (*Begin);
404 }
405 return S;
406}
407
408template <typename IteratorT>
409inline std::string join_impl(IteratorT Begin, IteratorT End,
410 StringRef Separator, std::forward_iterator_tag) {
411 std::string S;
412 if (Begin == End)
413 return S;
414
415 size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
416 for (IteratorT I = Begin; I != End; ++I)
417 Len += (*I).size();
418 S.reserve(res: Len);
419 size_t PrevCapacity = S.capacity();
420 (void)PrevCapacity;
421 S += (*Begin);
422 while (++Begin != End) {
423 S += Separator;
424 S += (*Begin);
425 }
426 assert(PrevCapacity == S.capacity() && "String grew during building");
427 return S;
428}
429
430template <typename Sep>
431inline void join_items_impl(std::string &Result, Sep Separator) {}
432
433template <typename Sep, typename Arg>
434inline void join_items_impl(std::string &Result, Sep Separator,
435 const Arg &Item) {
436 Result += Item;
437}
438
439template <typename Sep, typename Arg1, typename... Args>
440inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1,
441 Args &&... Items) {
442 Result += A1;
443 Result += Separator;
444 join_items_impl(Result, Separator, std::forward<Args>(Items)...);
445}
446
447inline size_t join_one_item_size(char) { return 1; }
448inline size_t join_one_item_size(const char *S) { return S ? ::strlen(s: S) : 0; }
449
450template <typename T> inline size_t join_one_item_size(const T &Str) {
451 return Str.size();
452}
453
454template <typename... Args> inline size_t join_items_size(Args &&...Items) {
455 return (0 + ... + join_one_item_size(std::forward<Args>(Items)));
456}
457
458} // end namespace detail
459
460/// Joins the strings in the range [Begin, End), adding Separator between
461/// the elements.
462template <typename IteratorT>
463inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
464 using tag = typename std::iterator_traits<IteratorT>::iterator_category;
465 return detail::join_impl(Begin, End, Separator, tag());
466}
467
468/// Joins the strings in the range [R.begin(), R.end()), adding Separator
469/// between the elements.
470template <typename Range>
471inline std::string join(Range &&R, StringRef Separator) {
472 return join(R.begin(), R.end(), Separator);
473}
474
475/// Joins the strings in the parameter pack \p Items, adding \p Separator
476/// between the elements. All arguments must be implicitly convertible to
477/// std::string, or there should be an overload of std::string::operator+=()
478/// that accepts the argument explicitly.
479template <typename Sep, typename... Args>
480inline std::string join_items(Sep Separator, Args &&... Items) {
481 std::string Result;
482 if (sizeof...(Items) == 0)
483 return Result;
484
485 size_t NS = detail::join_one_item_size(Separator);
486 size_t NI = detail::join_items_size(std::forward<Args>(Items)...);
487 Result.reserve(res: NI + (sizeof...(Items) - 1) * NS + 1);
488 detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...);
489 return Result;
490}
491
492/// A helper class to return the specified delimiter string after the first
493/// invocation of operator StringRef(). Used to generate a comma-separated
494/// list from a loop like so:
495///
496/// \code
497/// ListSeparator LS;
498/// for (auto &I : C)
499/// OS << LS << I.getName();
500/// \end
501class ListSeparator {
502 bool First = true;
503 StringRef Separator;
504
505public:
506 ListSeparator(StringRef Separator = ", ") : Separator(Separator) {}
507 operator StringRef() {
508 if (First) {
509 First = false;
510 return {};
511 }
512 return Separator;
513 }
514};
515
516/// A forward iterator over partitions of string over a separator.
517class SplittingIterator
518 : public iterator_facade_base<SplittingIterator, std::forward_iterator_tag,
519 StringRef> {
520 char SeparatorStorage;
521 StringRef Current;
522 StringRef Next;
523 StringRef Separator;
524
525public:
526 SplittingIterator(StringRef Str, StringRef Separator)
527 : Next(Str), Separator(Separator) {
528 ++*this;
529 }
530
531 SplittingIterator(StringRef Str, char Separator)
532 : SeparatorStorage(Separator), Next(Str),
533 Separator(&SeparatorStorage, 1) {
534 ++*this;
535 }
536
537 SplittingIterator(const SplittingIterator &R)
538 : SeparatorStorage(R.SeparatorStorage), Current(R.Current), Next(R.Next),
539 Separator(R.Separator) {
540 if (R.Separator.data() == &R.SeparatorStorage)
541 Separator = StringRef(&SeparatorStorage, 1);
542 }
543
544 SplittingIterator &operator=(const SplittingIterator &R) {
545 if (this == &R)
546 return *this;
547
548 SeparatorStorage = R.SeparatorStorage;
549 Current = R.Current;
550 Next = R.Next;
551 Separator = R.Separator;
552 if (R.Separator.data() == &R.SeparatorStorage)
553 Separator = StringRef(&SeparatorStorage, 1);
554 return *this;
555 }
556
557 bool operator==(const SplittingIterator &R) const {
558 assert(Separator == R.Separator);
559 return Current.data() == R.Current.data();
560 }
561
562 const StringRef &operator*() const { return Current; }
563
564 StringRef &operator*() { return Current; }
565
566 SplittingIterator &operator++() {
567 std::tie(args&: Current, args&: Next) = Next.split(Separator);
568 return *this;
569 }
570};
571
572/// Split the specified string over a separator and return a range-compatible
573/// iterable over its partitions. Used to permit conveniently iterating
574/// over separated strings like so:
575///
576/// \code
577/// for (StringRef x : llvm::split("foo,bar,baz", ","))
578/// ...;
579/// \end
580///
581/// Note that the passed string must remain valid throuhgout lifetime
582/// of the iterators.
583inline iterator_range<SplittingIterator> split(StringRef Str, StringRef Separator) {
584 return {SplittingIterator(Str, Separator),
585 SplittingIterator(StringRef(), Separator)};
586}
587
588inline iterator_range<SplittingIterator> split(StringRef Str, char Separator) {
589 return {SplittingIterator(Str, Separator),
590 SplittingIterator(StringRef(), Separator)};
591}
592
593} // end namespace llvm
594
595#endif // LLVM_ADT_STRINGEXTRAS_H
596

source code of include/llvm-17/llvm/ADT/StringExtras.h