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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/Support/DataTypes.h"
18 #include "llvm/ADT/APFloat.h"
19 #include "llvm/ADT/DenseMapInfo.h"
20 #include "llvm/ADT/StringRef.h"
21 #include <cctype>
22 #include <cstdio>
23 #include <string>
24 
25 namespace llvm {
26 template<typename T> class SmallVectorImpl;
27 
28 /// hexdigit - Return the hexadecimal character for the
29 /// given number \arg X (which should be less than 16).
30 static inline char hexdigit(unsigned X, bool LowerCase = false) {
31   const char HexChar = LowerCase ? 'a' : 'A';
32   return X < 10 ? '0' + X : HexChar + X - 10;
33 }
34 
35 /// utohex_buffer - Emit the specified number into the buffer specified by
36 /// BufferEnd, returning a pointer to the start of the string.  This can be used
37 /// like this: (note that the buffer must be large enough to handle any number):
38 ///    char Buffer[40];
39 ///    printf("0x%s", utohex_buffer(X, Buffer+40));
40 ///
41 /// This should only be used with unsigned types.
42 ///
43 template<typename IntTy>
utohex_buffer(IntTy X,char * BufferEnd)44 static inline char *utohex_buffer(IntTy X, char *BufferEnd) {
45   char *BufPtr = BufferEnd;
46   *--BufPtr = 0;      // Null terminate buffer.
47   if (X == 0) {
48     *--BufPtr = '0';  // Handle special case.
49     return BufPtr;
50   }
51 
52   while (X) {
53     unsigned char Mod = static_cast<unsigned char>(X) & 15;
54     *--BufPtr = hexdigit(Mod);
55     X >>= 4;
56   }
57   return BufPtr;
58 }
59 
utohexstr(uint64_t X)60 static inline std::string utohexstr(uint64_t X) {
61   char Buffer[17];
62   return utohex_buffer(X, Buffer+17);
63 }
64 
65 static inline std::string utostr_32(uint32_t X, bool isNeg = false) {
66   char Buffer[11];
67   char *BufPtr = Buffer+11;
68 
69   if (X == 0) *--BufPtr = '0';  // Handle special case...
70 
71   while (X) {
72     *--BufPtr = '0' + char(X % 10);
73     X /= 10;
74   }
75 
76   if (isNeg) *--BufPtr = '-';   // Add negative sign...
77 
78   return std::string(BufPtr, Buffer+11);
79 }
80 
81 static inline std::string utostr(uint64_t X, bool isNeg = false) {
82   char Buffer[21];
83   char *BufPtr = Buffer+21;
84 
85   if (X == 0) *--BufPtr = '0';  // Handle special case...
86 
87   while (X) {
88     *--BufPtr = '0' + char(X % 10);
89     X /= 10;
90   }
91 
92   if (isNeg) *--BufPtr = '-';   // Add negative sign...
93   return std::string(BufPtr, Buffer+21);
94 }
95 
96 
itostr(int64_t X)97 static inline std::string itostr(int64_t X) {
98   if (X < 0)
99     return utostr(static_cast<uint64_t>(-X), true);
100   else
101     return utostr(static_cast<uint64_t>(X));
102 }
103 
ftostr(double V)104 static inline std::string ftostr(double V) {
105   char Buffer[200];
106   sprintf(Buffer, "%20.6e", V);
107   char *B = Buffer;
108   while (*B == ' ') ++B;
109   return B;
110 }
111 
ftostr(const APFloat & V)112 static inline std::string ftostr(const APFloat& V) {
113   if (&V.getSemantics() == &APFloat::IEEEdouble)
114     return ftostr(V.convertToDouble());
115   else if (&V.getSemantics() == &APFloat::IEEEsingle)
116     return ftostr((double)V.convertToFloat());
117   return "<unknown format in ftostr>"; // error
118 }
119 
LowercaseString(const std::string & S)120 static inline std::string LowercaseString(const std::string &S) {
121   std::string result(S);
122   for (unsigned i = 0; i < S.length(); ++i)
123     if (isupper(result[i]))
124       result[i] = char(tolower(result[i]));
125   return result;
126 }
127 
UppercaseString(const std::string & S)128 static inline std::string UppercaseString(const std::string &S) {
129   std::string result(S);
130   for (unsigned i = 0; i < S.length(); ++i)
131     if (islower(result[i]))
132       result[i] = char(toupper(result[i]));
133   return result;
134 }
135 
136 /// StrInStrNoCase - Portable version of strcasestr.  Locates the first
137 /// occurrence of string 's1' in string 's2', ignoring case.  Returns
138 /// the offset of s2 in s1 or npos if s2 cannot be found.
139 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
140 
141 /// getToken - This function extracts one token from source, ignoring any
142 /// leading characters that appear in the Delimiters string, and ending the
143 /// token at any of the characters that appear in the Delimiters string.  If
144 /// there are no tokens in the source string, an empty string is returned.
145 /// The function returns a pair containing the extracted token and the
146 /// remaining tail string.
147 std::pair<StringRef, StringRef> getToken(StringRef Source,
148                                          StringRef Delimiters = " \t\n\v\f\r");
149 
150 /// SplitString - Split up the specified string according to the specified
151 /// delimiters, appending the result fragments to the output list.
152 void SplitString(StringRef Source,
153                  SmallVectorImpl<StringRef> &OutFragments,
154                  StringRef Delimiters = " \t\n\v\f\r");
155 
156 /// HashString - Hash function for strings.
157 ///
158 /// This is the Bernstein hash function.
159 //
160 // FIXME: Investigate whether a modified bernstein hash function performs
161 // better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
162 //   X*33+c -> X*33^c
163 static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
164   for (unsigned i = 0, e = Str.size(); i != e; ++i)
165     Result = Result * 33 + Str[i];
166   return Result;
167 }
168 
169 } // End llvm namespace
170 
171 #endif
172