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 21 namespace llvm { 22 class raw_ostream; 23 template<typename T> class SmallVectorImpl; 24 25 /// hexdigit - Return the hexadecimal character for the 26 /// given number \p X (which should be less than 16). 27 static inline char hexdigit(unsigned X, bool LowerCase = false) { 28 const char HexChar = LowerCase ? 'a' : 'A'; 29 return X < 10 ? '0' + X : HexChar + X - 10; 30 } 31 32 /// Construct a string ref from a boolean. 33 static inline StringRef toStringRef(bool B) { 34 return StringRef(B ? "true" : "false"); 35 } 36 37 /// Interpret the given character \p C as a hexadecimal digit and return its 38 /// value. 39 /// 40 /// If \p C is not a valid hex digit, -1U is returned. 41 static inline unsigned hexDigitValue(char C) { 42 if (C >= '0' && C <= '9') return C-'0'; 43 if (C >= 'a' && C <= 'f') return C-'a'+10U; 44 if (C >= 'A' && C <= 'F') return C-'A'+10U; 45 return -1U; 46 } 47 48 static inline std::string utohexstr(uint64_t X, bool LowerCase = false) { 49 char Buffer[17]; 50 char *BufPtr = std::end(Buffer); 51 52 if (X == 0) *--BufPtr = '0'; 53 54 while (X) { 55 unsigned char Mod = static_cast<unsigned char>(X) & 15; 56 *--BufPtr = hexdigit(Mod, LowerCase); 57 X >>= 4; 58 } 59 60 return std::string(BufPtr, std::end(Buffer)); 61 } 62 63 /// Convert buffer \p Input to its hexadecimal representation. 64 /// The returned string is double the size of \p Input. 65 static inline std::string toHex(StringRef Input) { 66 static const char *const LUT = "0123456789ABCDEF"; 67 size_t Length = Input.size(); 68 69 std::string Output; 70 Output.reserve(2 * Length); 71 for (size_t i = 0; i < Length; ++i) { 72 const unsigned char c = Input[i]; 73 Output.push_back(LUT[c >> 4]); 74 Output.push_back(LUT[c & 15]); 75 } 76 return Output; 77 } 78 79 static inline std::string utostr(uint64_t X, bool isNeg = false) { 80 char Buffer[21]; 81 char *BufPtr = std::end(Buffer); 82 83 if (X == 0) *--BufPtr = '0'; // Handle special case... 84 85 while (X) { 86 *--BufPtr = '0' + char(X % 10); 87 X /= 10; 88 } 89 90 if (isNeg) *--BufPtr = '-'; // Add negative sign... 91 return std::string(BufPtr, std::end(Buffer)); 92 } 93 94 95 static inline std::string itostr(int64_t X) { 96 if (X < 0) 97 return utostr(static_cast<uint64_t>(-X), true); 98 else 99 return utostr(static_cast<uint64_t>(X)); 100 } 101 102 /// StrInStrNoCase - Portable version of strcasestr. Locates the first 103 /// occurrence of string 's1' in string 's2', ignoring case. Returns 104 /// the offset of s2 in s1 or npos if s2 cannot be found. 105 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2); 106 107 /// getToken - This function extracts one token from source, ignoring any 108 /// leading characters that appear in the Delimiters string, and ending the 109 /// token at any of the characters that appear in the Delimiters string. If 110 /// there are no tokens in the source string, an empty string is returned. 111 /// The function returns a pair containing the extracted token and the 112 /// remaining tail string. 113 std::pair<StringRef, StringRef> getToken(StringRef Source, 114 StringRef Delimiters = " \t\n\v\f\r"); 115 116 /// SplitString - Split up the specified string according to the specified 117 /// delimiters, appending the result fragments to the output list. 118 void SplitString(StringRef Source, 119 SmallVectorImpl<StringRef> &OutFragments, 120 StringRef Delimiters = " \t\n\v\f\r"); 121 122 /// HashString - Hash function for strings. 123 /// 124 /// This is the Bernstein hash function. 125 // 126 // FIXME: Investigate whether a modified bernstein hash function performs 127 // better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx 128 // X*33+c -> X*33^c 129 static inline unsigned HashString(StringRef Str, unsigned Result = 0) { 130 for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i) 131 Result = Result * 33 + (unsigned char)Str[i]; 132 return Result; 133 } 134 135 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th). 136 static inline StringRef getOrdinalSuffix(unsigned Val) { 137 // It is critically important that we do this perfectly for 138 // user-written sequences with over 100 elements. 139 switch (Val % 100) { 140 case 11: 141 case 12: 142 case 13: 143 return "th"; 144 default: 145 switch (Val % 10) { 146 case 1: return "st"; 147 case 2: return "nd"; 148 case 3: return "rd"; 149 default: return "th"; 150 } 151 } 152 } 153 154 /// PrintEscapedString - Print each character of the specified string, escaping 155 /// it if it is not printable or if it is an escape char. 156 void PrintEscapedString(StringRef Name, raw_ostream &Out); 157 158 namespace detail { 159 160 template <typename IteratorT> 161 inline std::string join_impl(IteratorT Begin, IteratorT End, 162 StringRef Separator, std::input_iterator_tag) { 163 std::string S; 164 if (Begin == End) 165 return S; 166 167 S += (*Begin); 168 while (++Begin != End) { 169 S += Separator; 170 S += (*Begin); 171 } 172 return S; 173 } 174 175 template <typename IteratorT> 176 inline std::string join_impl(IteratorT Begin, IteratorT End, 177 StringRef Separator, std::forward_iterator_tag) { 178 std::string S; 179 if (Begin == End) 180 return S; 181 182 size_t Len = (std::distance(Begin, End) - 1) * Separator.size(); 183 for (IteratorT I = Begin; I != End; ++I) 184 Len += (*Begin).size(); 185 S.reserve(Len); 186 S += (*Begin); 187 while (++Begin != End) { 188 S += Separator; 189 S += (*Begin); 190 } 191 return S; 192 } 193 194 template <typename Sep> 195 inline void join_items_impl(std::string &Result, Sep Separator) {} 196 197 template <typename Sep, typename Arg> 198 inline void join_items_impl(std::string &Result, Sep Separator, 199 const Arg &Item) { 200 Result += Item; 201 } 202 203 template <typename Sep, typename Arg1, typename... Args> 204 inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1, 205 Args &&... Items) { 206 Result += A1; 207 Result += Separator; 208 join_items_impl(Result, Separator, std::forward<Args>(Items)...); 209 } 210 211 inline size_t join_one_item_size(char C) { return 1; } 212 inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; } 213 214 template <typename T> inline size_t join_one_item_size(const T &Str) { 215 return Str.size(); 216 } 217 218 inline size_t join_items_size() { return 0; } 219 220 template <typename A1> inline size_t join_items_size(const A1 &A) { 221 return join_one_item_size(A); 222 } 223 template <typename A1, typename... Args> 224 inline size_t join_items_size(const A1 &A, Args &&... Items) { 225 return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...); 226 } 227 } 228 229 /// Joins the strings in the range [Begin, End), adding Separator between 230 /// the elements. 231 template <typename IteratorT> 232 inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) { 233 typedef typename std::iterator_traits<IteratorT>::iterator_category tag; 234 return detail::join_impl(Begin, End, Separator, tag()); 235 } 236 237 /// Joins the strings in the range [R.begin(), R.end()), adding Separator 238 /// between the elements. 239 template <typename Range> 240 inline std::string join(Range &&R, StringRef Separator) { 241 return join(R.begin(), R.end(), Separator); 242 } 243 244 /// Joins the strings in the parameter pack \p Items, adding \p Separator 245 /// between the elements. All arguments must be implicitly convertible to 246 /// std::string, or there should be an overload of std::string::operator+=() 247 /// that accepts the argument explicitly. 248 template <typename Sep, typename... Args> 249 inline std::string join_items(Sep Separator, Args &&... Items) { 250 std::string Result; 251 if (sizeof...(Items) == 0) 252 return Result; 253 254 size_t NS = detail::join_one_item_size(Separator); 255 size_t NI = detail::join_items_size(std::forward<Args>(Items)...); 256 Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1); 257 detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...); 258 return Result; 259 } 260 261 } // End llvm namespace 262 263 #endif 264