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
47/// utohex_buffer - Emit the specified number into the buffer specified by
48/// BufferEnd, returning a pointer to the start of the string.  This can be used
49/// like this: (note that the buffer must be large enough to handle any number):
50///    char Buffer[40];
51///    printf("0x%s", utohex_buffer(X, Buffer+40));
52///
53/// This should only be used with unsigned types.
54///
55template<typename IntTy>
56static inline char *utohex_buffer(IntTy X, char *BufferEnd) {
57  char *BufPtr = BufferEnd;
58  *--BufPtr = 0;      // Null terminate buffer.
59  if (X == 0) {
60    *--BufPtr = '0';  // Handle special case.
61    return BufPtr;
62  }
63
64  while (X) {
65    unsigned char Mod = static_cast<unsigned char>(X) & 15;
66    *--BufPtr = hexdigit(Mod);
67    X >>= 4;
68  }
69  return BufPtr;
70}
71
72static inline std::string utohexstr(uint64_t X) {
73  char Buffer[17];
74  return utohex_buffer(X, Buffer+17);
75}
76
77static inline std::string utostr_32(uint32_t X, bool isNeg = false) {
78  char Buffer[11];
79  char *BufPtr = Buffer+11;
80
81  if (X == 0) *--BufPtr = '0';  // Handle special case...
82
83  while (X) {
84    *--BufPtr = '0' + char(X % 10);
85    X /= 10;
86  }
87
88  if (isNeg) *--BufPtr = '-';   // Add negative sign...
89
90  return std::string(BufPtr, Buffer+11);
91}
92
93static inline std::string utostr(uint64_t X, bool isNeg = false) {
94  char Buffer[21];
95  char *BufPtr = Buffer+21;
96
97  if (X == 0) *--BufPtr = '0';  // Handle special case...
98
99  while (X) {
100    *--BufPtr = '0' + char(X % 10);
101    X /= 10;
102  }
103
104  if (isNeg) *--BufPtr = '-';   // Add negative sign...
105  return std::string(BufPtr, Buffer+21);
106}
107
108
109static inline std::string itostr(int64_t X) {
110  if (X < 0)
111    return utostr(static_cast<uint64_t>(-X), true);
112  else
113    return utostr(static_cast<uint64_t>(X));
114}
115
116/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
117/// occurrence of string 's1' in string 's2', ignoring case.  Returns
118/// the offset of s2 in s1 or npos if s2 cannot be found.
119StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
120
121/// getToken - This function extracts one token from source, ignoring any
122/// leading characters that appear in the Delimiters string, and ending the
123/// token at any of the characters that appear in the Delimiters string.  If
124/// there are no tokens in the source string, an empty string is returned.
125/// The function returns a pair containing the extracted token and the
126/// remaining tail string.
127std::pair<StringRef, StringRef> getToken(StringRef Source,
128                                         StringRef Delimiters = " \t\n\v\f\r");
129
130/// SplitString - Split up the specified string according to the specified
131/// delimiters, appending the result fragments to the output list.
132void SplitString(StringRef Source,
133                 SmallVectorImpl<StringRef> &OutFragments,
134                 StringRef Delimiters = " \t\n\v\f\r");
135
136/// HashString - Hash function for strings.
137///
138/// This is the Bernstein hash function.
139//
140// FIXME: Investigate whether a modified bernstein hash function performs
141// better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
142//   X*33+c -> X*33^c
143static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
144  for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i)
145    Result = Result * 33 + (unsigned char)Str[i];
146  return Result;
147}
148
149/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
150static inline StringRef getOrdinalSuffix(unsigned Val) {
151  // It is critically important that we do this perfectly for
152  // user-written sequences with over 100 elements.
153  switch (Val % 100) {
154  case 11:
155  case 12:
156  case 13:
157    return "th";
158  default:
159    switch (Val % 10) {
160      case 1: return "st";
161      case 2: return "nd";
162      case 3: return "rd";
163      default: return "th";
164    }
165  }
166}
167
168template <typename IteratorT>
169inline std::string join_impl(IteratorT Begin, IteratorT End,
170                             StringRef Separator, std::input_iterator_tag) {
171  std::string S;
172  if (Begin == End)
173    return S;
174
175  S += (*Begin);
176  while (++Begin != End) {
177    S += Separator;
178    S += (*Begin);
179  }
180  return S;
181}
182
183template <typename IteratorT>
184inline std::string join_impl(IteratorT Begin, IteratorT End,
185                             StringRef Separator, std::forward_iterator_tag) {
186  std::string S;
187  if (Begin == End)
188    return S;
189
190  size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
191  for (IteratorT I = Begin; I != End; ++I)
192    Len += (*Begin).size();
193  S.reserve(Len);
194  S += (*Begin);
195  while (++Begin != End) {
196    S += Separator;
197    S += (*Begin);
198  }
199  return S;
200}
201
202/// Joins the strings in the range [Begin, End), adding Separator between
203/// the elements.
204template <typename IteratorT>
205inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
206  typedef typename std::iterator_traits<IteratorT>::iterator_category tag;
207  return join_impl(Begin, End, Separator, tag());
208}
209
210} // End llvm namespace
211
212#endif
213