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 20 namespace llvm { 21 template<typename T> class SmallVectorImpl; 22 23 /// hexdigit - Return the hexadecimal character for the 24 /// given number \p X (which should be less than 16). 25 static inline char hexdigit(unsigned X, bool LowerCase = false) { 26 const char HexChar = LowerCase ? 'a' : 'A'; 27 return X < 10 ? '0' + X : HexChar + X - 10; 28 } 29 30 /// Interpret the given character \p C as a hexadecimal digit and return its 31 /// value. 32 /// 33 /// If \p C is not a valid hex digit, -1U is returned. 34 static inline unsigned hexDigitValue(char C) { 35 if (C >= '0' && C <= '9') return C-'0'; 36 if (C >= 'a' && C <= 'f') return C-'a'+10U; 37 if (C >= 'A' && C <= 'F') return C-'A'+10U; 38 return -1U; 39 } 40 41 /// utohex_buffer - Emit the specified number into the buffer specified by 42 /// BufferEnd, returning a pointer to the start of the string. This can be used 43 /// like this: (note that the buffer must be large enough to handle any number): 44 /// char Buffer[40]; 45 /// printf("0x%s", utohex_buffer(X, Buffer+40)); 46 /// 47 /// This should only be used with unsigned types. 48 /// 49 template<typename IntTy> 50 static inline char *utohex_buffer(IntTy X, char *BufferEnd) { 51 char *BufPtr = BufferEnd; 52 *--BufPtr = 0; // Null terminate buffer. 53 if (X == 0) { 54 *--BufPtr = '0'; // Handle special case. 55 return BufPtr; 56 } 57 58 while (X) { 59 unsigned char Mod = static_cast<unsigned char>(X) & 15; 60 *--BufPtr = hexdigit(Mod); 61 X >>= 4; 62 } 63 return BufPtr; 64 } 65 66 static inline std::string utohexstr(uint64_t X) { 67 char Buffer[17]; 68 return utohex_buffer(X, Buffer+17); 69 } 70 71 static inline std::string utostr_32(uint32_t X, bool isNeg = false) { 72 char Buffer[11]; 73 char *BufPtr = Buffer+11; 74 75 if (X == 0) *--BufPtr = '0'; // Handle special case... 76 77 while (X) { 78 *--BufPtr = '0' + char(X % 10); 79 X /= 10; 80 } 81 82 if (isNeg) *--BufPtr = '-'; // Add negative sign... 83 84 return std::string(BufPtr, Buffer+11); 85 } 86 87 static inline std::string utostr(uint64_t X, bool isNeg = false) { 88 char Buffer[21]; 89 char *BufPtr = Buffer+21; 90 91 if (X == 0) *--BufPtr = '0'; // Handle special case... 92 93 while (X) { 94 *--BufPtr = '0' + char(X % 10); 95 X /= 10; 96 } 97 98 if (isNeg) *--BufPtr = '-'; // Add negative sign... 99 return std::string(BufPtr, Buffer+21); 100 } 101 102 103 static inline std::string itostr(int64_t X) { 104 if (X < 0) 105 return utostr(static_cast<uint64_t>(-X), true); 106 else 107 return utostr(static_cast<uint64_t>(X)); 108 } 109 110 /// StrInStrNoCase - Portable version of strcasestr. Locates the first 111 /// occurrence of string 's1' in string 's2', ignoring case. Returns 112 /// the offset of s2 in s1 or npos if s2 cannot be found. 113 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2); 114 115 /// getToken - This function extracts one token from source, ignoring any 116 /// leading characters that appear in the Delimiters string, and ending the 117 /// token at any of the characters that appear in the Delimiters string. If 118 /// there are no tokens in the source string, an empty string is returned. 119 /// The function returns a pair containing the extracted token and the 120 /// remaining tail string. 121 std::pair<StringRef, StringRef> getToken(StringRef Source, 122 StringRef Delimiters = " \t\n\v\f\r"); 123 124 /// SplitString - Split up the specified string according to the specified 125 /// delimiters, appending the result fragments to the output list. 126 void SplitString(StringRef Source, 127 SmallVectorImpl<StringRef> &OutFragments, 128 StringRef Delimiters = " \t\n\v\f\r"); 129 130 /// HashString - Hash function for strings. 131 /// 132 /// This is the Bernstein hash function. 133 // 134 // FIXME: Investigate whether a modified bernstein hash function performs 135 // better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx 136 // X*33+c -> X*33^c 137 static inline unsigned HashString(StringRef Str, unsigned Result = 0) { 138 for (unsigned i = 0, e = Str.size(); i != e; ++i) 139 Result = Result * 33 + (unsigned char)Str[i]; 140 return Result; 141 } 142 143 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th). 144 static inline StringRef getOrdinalSuffix(unsigned Val) { 145 // It is critically important that we do this perfectly for 146 // user-written sequences with over 100 elements. 147 switch (Val % 100) { 148 case 11: 149 case 12: 150 case 13: 151 return "th"; 152 default: 153 switch (Val % 10) { 154 case 1: return "st"; 155 case 2: return "nd"; 156 case 3: return "rd"; 157 default: return "th"; 158 } 159 } 160 } 161 162 } // End llvm namespace 163 164 #endif 165
