1//===- llvm/ADT/StringExtras.h - Useful string functions --------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
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/ArrayRef.h"
18#include "llvm/ADT/SmallString.h"
19#include "llvm/ADT/StringRef.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).
36static inline 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/// Construct a string ref from a boolean.
42static inline StringRef toStringRef(bool B) {
43  return StringRef(B ? "true" : "false");
44}
45
46/// Construct a string ref from an array ref of unsigned chars.
47static inline StringRef toStringRef(ArrayRef<uint8_t> Input) {
48  return StringRef(reinterpret_cast<const char *>(Input.begin()), Input.size());
49}
50
51/// Interpret the given character \p C as a hexadecimal digit and return its
52/// value.
53///
54/// If \p C is not a valid hex digit, -1U is returned.
55static inline unsigned hexDigitValue(char C) {
56  if (C >= '0' && C <= '9') return C-'0';
57  if (C >= 'a' && C <= 'f') return C-'a'+10U;
58  if (C >= 'A' && C <= 'F') return C-'A'+10U;
59  return -1U;
60}
61
62/// Checks if character \p C is one of the 10 decimal digits.
63static inline bool isDigit(char C) { return C >= '0' && C <= '9'; }
64
65/// Checks if character \p C is a hexadecimal numeric character.
66static inline bool isHexDigit(char C) { return hexDigitValue(C) != -1U; }
67
68/// Checks if character \p C is a valid letter as classified by "C" locale.
69static inline bool isAlpha(char C) {
70  return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');
71}
72
73/// Checks whether character \p C is either a decimal digit or an uppercase or
74/// lowercase letter as classified by "C" locale.
75static inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); }
76
77static inline std::string utohexstr(uint64_t X, bool LowerCase = false) {
78  char Buffer[17];
79  char *BufPtr = std::end(Buffer);
80
81  if (X == 0) *--BufPtr = '0';
82
83  while (X) {
84    unsigned char Mod = static_cast<unsigned char>(X) & 15;
85    *--BufPtr = hexdigit(Mod, LowerCase);
86    X >>= 4;
87  }
88
89  return std::string(BufPtr, std::end(Buffer));
90}
91
92/// Convert buffer \p Input to its hexadecimal representation.
93/// The returned string is double the size of \p Input.
94inline std::string toHex(StringRef Input) {
95  static const char *const LUT = "0123456789ABCDEF";
96  size_t Length = Input.size();
97
98  std::string Output;
99  Output.reserve(2 * Length);
100  for (size_t i = 0; i < Length; ++i) {
101    const unsigned char c = Input[i];
102    Output.push_back(LUT[c >> 4]);
103    Output.push_back(LUT[c & 15]);
104  }
105  return Output;
106}
107
108inline std::string toHex(ArrayRef<uint8_t> Input) {
109  return toHex(toStringRef(Input));
110}
111
112static inline uint8_t hexFromNibbles(char MSB, char LSB) {
113  unsigned U1 = hexDigitValue(MSB);
114  unsigned U2 = hexDigitValue(LSB);
115  assert(U1 != -1U && U2 != -1U);
116
117  return static_cast<uint8_t>((U1 << 4) | U2);
118}
119
120/// Convert hexadecimal string \p Input to its binary representation.
121/// The return string is half the size of \p Input.
122static inline std::string fromHex(StringRef Input) {
123  if (Input.empty())
124    return std::string();
125
126  std::string Output;
127  Output.reserve((Input.size() + 1) / 2);
128  if (Input.size() % 2 == 1) {
129    Output.push_back(hexFromNibbles('0', Input.front()));
130    Input = Input.drop_front();
131  }
132
133  assert(Input.size() % 2 == 0);
134  while (!Input.empty()) {
135    uint8_t Hex = hexFromNibbles(Input[0], Input[1]);
136    Output.push_back(Hex);
137    Input = Input.drop_front(2);
138  }
139  return Output;
140}
141
142/// \brief Convert the string \p S to an integer of the specified type using
143/// the radix \p Base.  If \p Base is 0, auto-detects the radix.
144/// Returns true if the number was successfully converted, false otherwise.
145template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) {
146  return !S.getAsInteger(Base, Num);
147}
148
149namespace detail {
150template <typename N>
151inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) {
152  SmallString<32> Storage;
153  StringRef S = T.toNullTerminatedStringRef(Storage);
154  char *End;
155  N Temp = StrTo(S.data(), &End);
156  if (*End != '\0')
157    return false;
158  Num = Temp;
159  return true;
160}
161}
162
163inline bool to_float(const Twine &T, float &Num) {
164  return detail::to_float(T, Num, strtof);
165}
166
167inline bool to_float(const Twine &T, double &Num) {
168  return detail::to_float(T, Num, strtod);
169}
170
171inline bool to_float(const Twine &T, long double &Num) {
172  return detail::to_float(T, Num, strtold);
173}
174
175static inline std::string utostr(uint64_t X, bool isNeg = false) {
176  char Buffer[21];
177  char *BufPtr = std::end(Buffer);
178
179  if (X == 0) *--BufPtr = '0';  // Handle special case...
180
181  while (X) {
182    *--BufPtr = '0' + char(X % 10);
183    X /= 10;
184  }
185
186  if (isNeg) *--BufPtr = '-';   // Add negative sign...
187  return std::string(BufPtr, std::end(Buffer));
188}
189
190static inline std::string itostr(int64_t X) {
191  if (X < 0)
192    return utostr(static_cast<uint64_t>(-X), true);
193  else
194    return utostr(static_cast<uint64_t>(X));
195}
196
197/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
198/// occurrence of string 's1' in string 's2', ignoring case.  Returns
199/// the offset of s2 in s1 or npos if s2 cannot be found.
200StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
201
202/// getToken - This function extracts one token from source, ignoring any
203/// leading characters that appear in the Delimiters string, and ending the
204/// token at any of the characters that appear in the Delimiters string.  If
205/// there are no tokens in the source string, an empty string is returned.
206/// The function returns a pair containing the extracted token and the
207/// remaining tail string.
208std::pair<StringRef, StringRef> getToken(StringRef Source,
209                                         StringRef Delimiters = " \t\n\v\f\r");
210
211/// SplitString - Split up the specified string according to the specified
212/// delimiters, appending the result fragments to the output list.
213void SplitString(StringRef Source,
214                 SmallVectorImpl<StringRef> &OutFragments,
215                 StringRef Delimiters = " \t\n\v\f\r");
216
217/// HashString - Hash function for strings.
218///
219/// This is the Bernstein hash function.
220//
221// FIXME: Investigate whether a modified bernstein hash function performs
222// better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
223//   X*33+c -> X*33^c
224static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
225  for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i)
226    Result = Result * 33 + (unsigned char)Str[i];
227  return Result;
228}
229
230/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
231static inline StringRef getOrdinalSuffix(unsigned Val) {
232  // It is critically important that we do this perfectly for
233  // user-written sequences with over 100 elements.
234  switch (Val % 100) {
235  case 11:
236  case 12:
237  case 13:
238    return "th";
239  default:
240    switch (Val % 10) {
241      case 1: return "st";
242      case 2: return "nd";
243      case 3: return "rd";
244      default: return "th";
245    }
246  }
247}
248
249/// PrintEscapedString - Print each character of the specified string, escaping
250/// it if it is not printable or if it is an escape char.
251void PrintEscapedString(StringRef Name, raw_ostream &Out);
252
253namespace detail {
254
255template <typename IteratorT>
256inline std::string join_impl(IteratorT Begin, IteratorT End,
257                             StringRef Separator, std::input_iterator_tag) {
258  std::string S;
259  if (Begin == End)
260    return S;
261
262  S += (*Begin);
263  while (++Begin != End) {
264    S += Separator;
265    S += (*Begin);
266  }
267  return S;
268}
269
270template <typename IteratorT>
271inline std::string join_impl(IteratorT Begin, IteratorT End,
272                             StringRef Separator, std::forward_iterator_tag) {
273  std::string S;
274  if (Begin == End)
275    return S;
276
277  size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
278  for (IteratorT I = Begin; I != End; ++I)
279    Len += (*Begin).size();
280  S.reserve(Len);
281  S += (*Begin);
282  while (++Begin != End) {
283    S += Separator;
284    S += (*Begin);
285  }
286  return S;
287}
288
289template <typename Sep>
290inline void join_items_impl(std::string &Result, Sep Separator) {}
291
292template <typename Sep, typename Arg>
293inline void join_items_impl(std::string &Result, Sep Separator,
294                            const Arg &Item) {
295  Result += Item;
296}
297
298template <typename Sep, typename Arg1, typename... Args>
299inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1,
300                            Args &&... Items) {
301  Result += A1;
302  Result += Separator;
303  join_items_impl(Result, Separator, std::forward<Args>(Items)...);
304}
305
306inline size_t join_one_item_size(char C) { return 1; }
307inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; }
308
309template <typename T> inline size_t join_one_item_size(const T &Str) {
310  return Str.size();
311}
312
313inline size_t join_items_size() { return 0; }
314
315template <typename A1> inline size_t join_items_size(const A1 &A) {
316  return join_one_item_size(A);
317}
318template <typename A1, typename... Args>
319inline size_t join_items_size(const A1 &A, Args &&... Items) {
320  return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...);
321}
322
323} // end namespace detail
324
325/// Joins the strings in the range [Begin, End), adding Separator between
326/// the elements.
327template <typename IteratorT>
328inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
329  using tag = typename std::iterator_traits<IteratorT>::iterator_category;
330  return detail::join_impl(Begin, End, Separator, tag());
331}
332
333/// Joins the strings in the range [R.begin(), R.end()), adding Separator
334/// between the elements.
335template <typename Range>
336inline std::string join(Range &&R, StringRef Separator) {
337  return join(R.begin(), R.end(), Separator);
338}
339
340/// Joins the strings in the parameter pack \p Items, adding \p Separator
341/// between the elements.  All arguments must be implicitly convertible to
342/// std::string, or there should be an overload of std::string::operator+=()
343/// that accepts the argument explicitly.
344template <typename Sep, typename... Args>
345inline std::string join_items(Sep Separator, Args &&... Items) {
346  std::string Result;
347  if (sizeof...(Items) == 0)
348    return Result;
349
350  size_t NS = detail::join_one_item_size(Separator);
351  size_t NI = detail::join_items_size(std::forward<Args>(Items)...);
352  Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1);
353  detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...);
354  return Result;
355}
356
357} // end namespace llvm
358
359#endif // LLVM_ADT_STRINGEXTRAS_H
360