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