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 <iterator> 18 #include "llvm/ADT/StringRef.h" 19 #include "llvm/Support/DataTypes.h" 20 21 namespace llvm { 22 template<typename T> class SmallVectorImpl; 23 24 /// hexdigit - Return the hexadecimal character for the 25 /// given number \p X (which should be less than 16). 26 static 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 /// Interpret the given character \p C as a hexadecimal digit and return its 32 /// value. 33 /// 34 /// If \p C is not a valid hex digit, -1U is returned. 35 static inline unsigned hexDigitValue(char C) { 36 if (C >= '0' && C <= '9') return C-'0'; 37 if (C >= 'a' && C <= 'f') return C-'a'+10U; 38 if (C >= 'A' && C <= 'F') return C-'A'+10U; 39 return -1U; 40 } 41 42 /// utohex_buffer - Emit the specified number into the buffer specified by 43 /// BufferEnd, returning a pointer to the start of the string. This can be used 44 /// like this: (note that the buffer must be large enough to handle any number): 45 /// char Buffer[40]; 46 /// printf("0x%s", utohex_buffer(X, Buffer+40)); 47 /// 48 /// This should only be used with unsigned types. 49 /// 50 template<typename IntTy> 51 static inline char *utohex_buffer(IntTy X, char *BufferEnd) { 52 char *BufPtr = BufferEnd; 53 *--BufPtr = 0; // Null terminate buffer. 54 if (X == 0) { 55 *--BufPtr = '0'; // Handle special case. 56 return BufPtr; 57 } 58 59 while (X) { 60 unsigned char Mod = static_cast<unsigned char>(X) & 15; 61 *--BufPtr = hexdigit(Mod); 62 X >>= 4; 63 } 64 return BufPtr; 65 } 66 67 static inline std::string utohexstr(uint64_t X) { 68 char Buffer[17]; 69 return utohex_buffer(X, Buffer+17); 70 } 71 72 static inline std::string utostr_32(uint32_t X, bool isNeg = false) { 73 char Buffer[11]; 74 char *BufPtr = Buffer+11; 75 76 if (X == 0) *--BufPtr = '0'; // Handle special case... 77 78 while (X) { 79 *--BufPtr = '0' + char(X % 10); 80 X /= 10; 81 } 82 83 if (isNeg) *--BufPtr = '-'; // Add negative sign... 84 85 return std::string(BufPtr, Buffer+11); 86 } 87 88 static inline std::string utostr(uint64_t X, bool isNeg = false) { 89 char Buffer[21]; 90 char *BufPtr = Buffer+21; 91 92 if (X == 0) *--BufPtr = '0'; // Handle special case... 93 94 while (X) { 95 *--BufPtr = '0' + char(X % 10); 96 X /= 10; 97 } 98 99 if (isNeg) *--BufPtr = '-'; // Add negative sign... 100 return std::string(BufPtr, Buffer+21); 101 } 102 103 104 static inline std::string itostr(int64_t X) { 105 if (X < 0) 106 return utostr(static_cast<uint64_t>(-X), true); 107 else 108 return utostr(static_cast<uint64_t>(X)); 109 } 110 111 /// StrInStrNoCase - Portable version of strcasestr. Locates the first 112 /// occurrence of string 's1' in string 's2', ignoring case. Returns 113 /// the offset of s2 in s1 or npos if s2 cannot be found. 114 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2); 115 116 /// getToken - This function extracts one token from source, ignoring any 117 /// leading characters that appear in the Delimiters string, and ending the 118 /// token at any of the characters that appear in the Delimiters string. If 119 /// there are no tokens in the source string, an empty string is returned. 120 /// The function returns a pair containing the extracted token and the 121 /// remaining tail string. 122 std::pair<StringRef, StringRef> getToken(StringRef Source, 123 StringRef Delimiters = " \t\n\v\f\r"); 124 125 /// SplitString - Split up the specified string according to the specified 126 /// delimiters, appending the result fragments to the output list. 127 void SplitString(StringRef Source, 128 SmallVectorImpl<StringRef> &OutFragments, 129 StringRef Delimiters = " \t\n\v\f\r"); 130 131 /// HashString - Hash function for strings. 132 /// 133 /// This is the Bernstein hash function. 134 // 135 // FIXME: Investigate whether a modified bernstein hash function performs 136 // better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx 137 // X*33+c -> X*33^c 138 static inline unsigned HashString(StringRef Str, unsigned Result = 0) { 139 for (unsigned i = 0, e = Str.size(); i != e; ++i) 140 Result = Result * 33 + (unsigned char)Str[i]; 141 return Result; 142 } 143 144 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th). 145 static inline StringRef getOrdinalSuffix(unsigned Val) { 146 // It is critically important that we do this perfectly for 147 // user-written sequences with over 100 elements. 148 switch (Val % 100) { 149 case 11: 150 case 12: 151 case 13: 152 return "th"; 153 default: 154 switch (Val % 10) { 155 case 1: return "st"; 156 case 2: return "nd"; 157 case 3: return "rd"; 158 default: return "th"; 159 } 160 } 161 } 162 163 template <typename IteratorT> 164 inline std::string join_impl(IteratorT Begin, IteratorT End, 165 StringRef Separator, std::input_iterator_tag) { 166 std::string S; 167 if (Begin == End) 168 return S; 169 170 S += (*Begin); 171 while (++Begin != End) { 172 S += Separator; 173 S += (*Begin); 174 } 175 return S; 176 } 177 178 template <typename IteratorT> 179 inline std::string join_impl(IteratorT Begin, IteratorT End, 180 StringRef Separator, std::forward_iterator_tag) { 181 std::string S; 182 if (Begin == End) 183 return S; 184 185 size_t Len = (std::distance(Begin, End) - 1) * Separator.size(); 186 for (IteratorT I = Begin; I != End; ++I) 187 Len += (*Begin).size(); 188 S.reserve(Len); 189 S += (*Begin); 190 while (++Begin != End) { 191 S += Separator; 192 S += (*Begin); 193 } 194 return S; 195 } 196 197 /// Joins the strings in the range [Begin, End), adding Separator between 198 /// the elements. 199 template <typename IteratorT> 200 inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) { 201 typedef typename std::iterator_traits<IteratorT>::iterator_category tag; 202 return join_impl(Begin, End, Separator, tag()); 203 } 204 205 } // End llvm namespace 206 207 #endif 208