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  if (C >= '0' && C <= '9') return C-'0';
70  if (C >= 'a' && C <= 'f') return C-'a'+10U;
71  if (C >= 'A' && C <= 'F') return C-'A'+10U;
72  return -1U;
73}
74
75/// Checks if character \p C is one of the 10 decimal digits.
76inline bool isDigit(char C) { return C >= '0' && C <= '9'; }
77
78/// Checks if character \p C is a hexadecimal numeric character.
79inline bool isHexDigit(char C) { return hexDigitValue(C) != -1U; }
80
81/// Checks if character \p C is a valid letter as classified by "C" locale.
82inline bool isAlpha(char C) {
83  return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');
84}
85
86/// Checks whether character \p C is either a decimal digit or an uppercase or
87/// lowercase letter as classified by "C" locale.
88inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); }
89
90/// Checks whether character \p C is valid ASCII (high bit is zero).
91inline bool isASCII(char C) { return static_cast<unsigned char>(C) <= 127; }
92
93/// Checks whether all characters in S are ASCII.
94inline bool isASCII(llvm::StringRef S) {
95  for (char C : S)
96    if (LLVM_UNLIKELY(!isASCII(C)))
97      return false;
98  return true;
99}
100
101/// Checks whether character \p C is printable.
102///
103/// Locale-independent version of the C standard library isprint whose results
104/// may differ on different platforms.
105inline bool isPrint(char C) {
106  unsigned char UC = static_cast<unsigned char>(C);
107  return (0x20 <= UC) && (UC <= 0x7E);
108}
109
110/// Returns the corresponding lowercase character if \p x is uppercase.
111inline char toLower(char x) {
112  if (x >= 'A' && x <= 'Z')
113    return x - 'A' + 'a';
114  return x;
115}
116
117/// Returns the corresponding uppercase character if \p x is lowercase.
118inline char toUpper(char x) {
119  if (x >= 'a' && x <= 'z')
120    return x - 'a' + 'A';
121  return x;
122}
123
124inline std::string utohexstr(uint64_t X, bool LowerCase = false) {
125  char Buffer[17];
126  char *BufPtr = std::end(Buffer);
127
128  if (X == 0) *--BufPtr = '0';
129
130  while (X) {
131    unsigned char Mod = static_cast<unsigned char>(X) & 15;
132    *--BufPtr = hexdigit(Mod, LowerCase);
133    X >>= 4;
134  }
135
136  return std::string(BufPtr, std::end(Buffer));
137}
138
139/// Convert buffer \p Input to its hexadecimal representation.
140/// The returned string is double the size of \p Input.
141inline std::string toHex(StringRef Input, bool LowerCase = false) {
142  static const char *const LUT = "0123456789ABCDEF";
143  const uint8_t Offset = LowerCase ? 32 : 0;
144  size_t Length = Input.size();
145
146  std::string Output;
147  Output.reserve(2 * Length);
148  for (size_t i = 0; i < Length; ++i) {
149    const unsigned char c = Input[i];
150    Output.push_back(LUT[c >> 4] | Offset);
151    Output.push_back(LUT[c & 15] | Offset);
152  }
153  return Output;
154}
155
156inline std::string toHex(ArrayRef<uint8_t> Input, bool LowerCase = false) {
157  return toHex(toStringRef(Input), LowerCase);
158}
159
160inline uint8_t hexFromNibbles(char MSB, char LSB) {
161  unsigned U1 = hexDigitValue(MSB);
162  unsigned U2 = hexDigitValue(LSB);
163  assert(U1 != -1U && U2 != -1U);
164
165  return static_cast<uint8_t>((U1 << 4) | U2);
166}
167
168/// Convert hexadecimal string \p Input to its binary representation.
169/// The return string is half the size of \p Input.
170inline std::string fromHex(StringRef Input) {
171  if (Input.empty())
172    return std::string();
173
174  std::string Output;
175  Output.reserve((Input.size() + 1) / 2);
176  if (Input.size() % 2 == 1) {
177    Output.push_back(hexFromNibbles('0', Input.front()));
178    Input = Input.drop_front();
179  }
180
181  assert(Input.size() % 2 == 0);
182  while (!Input.empty()) {
183    uint8_t Hex = hexFromNibbles(Input[0], Input[1]);
184    Output.push_back(Hex);
185    Input = Input.drop_front(2);
186  }
187  return Output;
188}
189
190/// Convert the string \p S to an integer of the specified type using
191/// the radix \p Base.  If \p Base is 0, auto-detects the radix.
192/// Returns true if the number was successfully converted, false otherwise.
193template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) {
194  return !S.getAsInteger(Base, Num);
195}
196
197namespace detail {
198template <typename N>
199inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) {
200  SmallString<32> Storage;
201  StringRef S = T.toNullTerminatedStringRef(Storage);
202  char *End;
203  N Temp = StrTo(S.data(), &End);
204  if (*End != '\0')
205    return false;
206  Num = Temp;
207  return true;
208}
209}
210
211inline bool to_float(const Twine &T, float &Num) {
212  return detail::to_float(T, Num, strtof);
213}
214
215inline bool to_float(const Twine &T, double &Num) {
216  return detail::to_float(T, Num, strtod);
217}
218
219inline bool to_float(const Twine &T, long double &Num) {
220  return detail::to_float(T, Num, strtold);
221}
222
223inline std::string utostr(uint64_t X, bool isNeg = false) {
224  char Buffer[21];
225  char *BufPtr = std::end(Buffer);
226
227  if (X == 0) *--BufPtr = '0';  // Handle special case...
228
229  while (X) {
230    *--BufPtr = '0' + char(X % 10);
231    X /= 10;
232  }
233
234  if (isNeg) *--BufPtr = '-';   // Add negative sign...
235  return std::string(BufPtr, std::end(Buffer));
236}
237
238inline std::string itostr(int64_t X) {
239  if (X < 0)
240    return utostr(static_cast<uint64_t>(-X), true);
241  else
242    return utostr(static_cast<uint64_t>(X));
243}
244
245/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
246/// occurrence of string 's1' in string 's2', ignoring case.  Returns
247/// the offset of s2 in s1 or npos if s2 cannot be found.
248StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
249
250/// getToken - This function extracts one token from source, ignoring any
251/// leading characters that appear in the Delimiters string, and ending the
252/// token at any of the characters that appear in the Delimiters string.  If
253/// there are no tokens in the source string, an empty string is returned.
254/// The function returns a pair containing the extracted token and the
255/// remaining tail string.
256std::pair<StringRef, StringRef> getToken(StringRef Source,
257                                         StringRef Delimiters = " \t\n\v\f\r");
258
259/// SplitString - Split up the specified string according to the specified
260/// delimiters, appending the result fragments to the output list.
261void SplitString(StringRef Source,
262                 SmallVectorImpl<StringRef> &OutFragments,
263                 StringRef Delimiters = " \t\n\v\f\r");
264
265/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
266inline StringRef getOrdinalSuffix(unsigned Val) {
267  // It is critically important that we do this perfectly for
268  // user-written sequences with over 100 elements.
269  switch (Val % 100) {
270  case 11:
271  case 12:
272  case 13:
273    return "th";
274  default:
275    switch (Val % 10) {
276      case 1: return "st";
277      case 2: return "nd";
278      case 3: return "rd";
279      default: return "th";
280    }
281  }
282}
283
284/// Print each character of the specified string, escaping it if it is not
285/// printable or if it is an escape char.
286void printEscapedString(StringRef Name, raw_ostream &Out);
287
288/// Print each character of the specified string, escaping HTML special
289/// characters.
290void printHTMLEscaped(StringRef String, raw_ostream &Out);
291
292/// printLowerCase - Print each character as lowercase if it is uppercase.
293void printLowerCase(StringRef String, raw_ostream &Out);
294
295namespace detail {
296
297template <typename IteratorT>
298inline std::string join_impl(IteratorT Begin, IteratorT End,
299                             StringRef Separator, std::input_iterator_tag) {
300  std::string S;
301  if (Begin == End)
302    return S;
303
304  S += (*Begin);
305  while (++Begin != End) {
306    S += Separator;
307    S += (*Begin);
308  }
309  return S;
310}
311
312template <typename IteratorT>
313inline std::string join_impl(IteratorT Begin, IteratorT End,
314                             StringRef Separator, std::forward_iterator_tag) {
315  std::string S;
316  if (Begin == End)
317    return S;
318
319  size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
320  for (IteratorT I = Begin; I != End; ++I)
321    Len += (*Begin).size();
322  S.reserve(Len);
323  S += (*Begin);
324  while (++Begin != End) {
325    S += Separator;
326    S += (*Begin);
327  }
328  return S;
329}
330
331template <typename Sep>
332inline void join_items_impl(std::string &Result, Sep Separator) {}
333
334template <typename Sep, typename Arg>
335inline void join_items_impl(std::string &Result, Sep Separator,
336                            const Arg &Item) {
337  Result += Item;
338}
339
340template <typename Sep, typename Arg1, typename... Args>
341inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1,
342                            Args &&... Items) {
343  Result += A1;
344  Result += Separator;
345  join_items_impl(Result, Separator, std::forward<Args>(Items)...);
346}
347
348inline size_t join_one_item_size(char) { return 1; }
349inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; }
350
351template <typename T> inline size_t join_one_item_size(const T &Str) {
352  return Str.size();
353}
354
355inline size_t join_items_size() { return 0; }
356
357template <typename A1> inline size_t join_items_size(const A1 &A) {
358  return join_one_item_size(A);
359}
360template <typename A1, typename... Args>
361inline size_t join_items_size(const A1 &A, Args &&... Items) {
362  return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...);
363}
364
365} // end namespace detail
366
367/// Joins the strings in the range [Begin, End), adding Separator between
368/// the elements.
369template <typename IteratorT>
370inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
371  using tag = typename std::iterator_traits<IteratorT>::iterator_category;
372  return detail::join_impl(Begin, End, Separator, tag());
373}
374
375/// Joins the strings in the range [R.begin(), R.end()), adding Separator
376/// between the elements.
377template <typename Range>
378inline std::string join(Range &&R, StringRef Separator) {
379  return join(R.begin(), R.end(), Separator);
380}
381
382/// Joins the strings in the parameter pack \p Items, adding \p Separator
383/// between the elements.  All arguments must be implicitly convertible to
384/// std::string, or there should be an overload of std::string::operator+=()
385/// that accepts the argument explicitly.
386template <typename Sep, typename... Args>
387inline std::string join_items(Sep Separator, Args &&... Items) {
388  std::string Result;
389  if (sizeof...(Items) == 0)
390    return Result;
391
392  size_t NS = detail::join_one_item_size(Separator);
393  size_t NI = detail::join_items_size(std::forward<Args>(Items)...);
394  Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1);
395  detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...);
396  return Result;
397}
398
399} // end namespace llvm
400
401#endif // LLVM_ADT_STRINGEXTRAS_H
402