StringExtras.h revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f
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