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/StringRef.h"
18#include "llvm/Support/DataTypes.h"
19#include <iterator>
20
21namespace llvm {
22template<typename T> class SmallVectorImpl;
23
24/// hexdigit - Return the hexadecimal character for the
25/// given number \p X (which should be less than 16).
26static inline char hexdigit(unsigned X, bool LowerCase = false) {
27  const char HexChar = LowerCase ? 'a' : 'A';
28  return X < 10 ? '0' + X : HexChar + X - 10;
29}
30
31/// Construct a string ref from a boolean.
32static inline StringRef toStringRef(bool B) {
33  return StringRef(B ? "true" : "false");
34}
35
36/// Interpret the given character \p C as a hexadecimal digit and return its
37/// value.
38///
39/// If \p C is not a valid hex digit, -1U is returned.
40static inline unsigned hexDigitValue(char C) {
41  if (C >= '0' && C <= '9') return C-'0';
42  if (C >= 'a' && C <= 'f') return C-'a'+10U;
43  if (C >= 'A' && C <= 'F') return C-'A'+10U;
44  return -1U;
45}
46
47static inline std::string utohexstr(uint64_t X, bool LowerCase = false) {
48  char Buffer[17];
49  char *BufPtr = std::end(Buffer);
50
51  if (X == 0) *--BufPtr = '0';
52
53  while (X) {
54    unsigned char Mod = static_cast<unsigned char>(X) & 15;
55    *--BufPtr = hexdigit(Mod, LowerCase);
56    X >>= 4;
57  }
58
59  return std::string(BufPtr, std::end(Buffer));
60}
61
62/// Convert buffer \p Input to its hexadecimal representation.
63/// The returned string is double the size of \p Input.
64static inline std::string toHex(StringRef Input) {
65  static const char *const LUT = "0123456789ABCDEF";
66  size_t Length = Input.size();
67
68  std::string Output;
69  Output.reserve(2 * Length);
70  for (size_t i = 0; i < Length; ++i) {
71    const unsigned char c = Input[i];
72    Output.push_back(LUT[c >> 4]);
73    Output.push_back(LUT[c & 15]);
74  }
75  return Output;
76}
77
78static inline std::string utostr(uint64_t X, bool isNeg = false) {
79  char Buffer[21];
80  char *BufPtr = std::end(Buffer);
81
82  if (X == 0) *--BufPtr = '0';  // Handle special case...
83
84  while (X) {
85    *--BufPtr = '0' + char(X % 10);
86    X /= 10;
87  }
88
89  if (isNeg) *--BufPtr = '-';   // Add negative sign...
90  return std::string(BufPtr, std::end(Buffer));
91}
92
93
94static inline std::string itostr(int64_t X) {
95  if (X < 0)
96    return utostr(static_cast<uint64_t>(-X), true);
97  else
98    return utostr(static_cast<uint64_t>(X));
99}
100
101/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
102/// occurrence of string 's1' in string 's2', ignoring case.  Returns
103/// the offset of s2 in s1 or npos if s2 cannot be found.
104StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
105
106/// getToken - This function extracts one token from source, ignoring any
107/// leading characters that appear in the Delimiters string, and ending the
108/// token at any of the characters that appear in the Delimiters string.  If
109/// there are no tokens in the source string, an empty string is returned.
110/// The function returns a pair containing the extracted token and the
111/// remaining tail string.
112std::pair<StringRef, StringRef> getToken(StringRef Source,
113                                         StringRef Delimiters = " \t\n\v\f\r");
114
115/// SplitString - Split up the specified string according to the specified
116/// delimiters, appending the result fragments to the output list.
117void SplitString(StringRef Source,
118                 SmallVectorImpl<StringRef> &OutFragments,
119                 StringRef Delimiters = " \t\n\v\f\r");
120
121/// HashString - Hash function for strings.
122///
123/// This is the Bernstein hash function.
124//
125// FIXME: Investigate whether a modified bernstein hash function performs
126// better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
127//   X*33+c -> X*33^c
128static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
129  for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i)
130    Result = Result * 33 + (unsigned char)Str[i];
131  return Result;
132}
133
134/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
135static inline StringRef getOrdinalSuffix(unsigned Val) {
136  // It is critically important that we do this perfectly for
137  // user-written sequences with over 100 elements.
138  switch (Val % 100) {
139  case 11:
140  case 12:
141  case 13:
142    return "th";
143  default:
144    switch (Val % 10) {
145      case 1: return "st";
146      case 2: return "nd";
147      case 3: return "rd";
148      default: return "th";
149    }
150  }
151}
152
153template <typename IteratorT>
154inline std::string join_impl(IteratorT Begin, IteratorT End,
155                             StringRef Separator, std::input_iterator_tag) {
156  std::string S;
157  if (Begin == End)
158    return S;
159
160  S += (*Begin);
161  while (++Begin != End) {
162    S += Separator;
163    S += (*Begin);
164  }
165  return S;
166}
167
168template <typename IteratorT>
169inline std::string join_impl(IteratorT Begin, IteratorT End,
170                             StringRef Separator, std::forward_iterator_tag) {
171  std::string S;
172  if (Begin == End)
173    return S;
174
175  size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
176  for (IteratorT I = Begin; I != End; ++I)
177    Len += (*Begin).size();
178  S.reserve(Len);
179  S += (*Begin);
180  while (++Begin != End) {
181    S += Separator;
182    S += (*Begin);
183  }
184  return S;
185}
186
187/// Joins the strings in the range [Begin, End), adding Separator between
188/// the elements.
189template <typename IteratorT>
190inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
191  typedef typename std::iterator_traits<IteratorT>::iterator_category tag;
192  return join_impl(Begin, End, Separator, tag());
193}
194
195} // End llvm namespace
196
197#endif
198