1 //===--- clang/Basic/CharInfo.h - Classifying ASCII Characters --*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef LLVM_CLANG_BASIC_CHARINFO_H
10 #define LLVM_CLANG_BASIC_CHARINFO_H
11
12 #include "clang/Basic/LLVM.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/Support/Compiler.h"
15 #include "llvm/Support/DataTypes.h"
16
17 namespace clang {
18 namespace charinfo {
19 extern const uint16_t InfoTable[256];
20
21 enum {
22 CHAR_HORZ_WS = 0x0001, // '\t', '\f', '\v'. Note, no '\0'
23 CHAR_VERT_WS = 0x0002, // '\r', '\n'
24 CHAR_SPACE = 0x0004, // ' '
25 CHAR_DIGIT = 0x0008, // 0-9
26 CHAR_XLETTER = 0x0010, // a-f,A-F
27 CHAR_UPPER = 0x0020, // A-Z
28 CHAR_LOWER = 0x0040, // a-z
29 CHAR_UNDER = 0x0080, // _
30 CHAR_PERIOD = 0x0100, // .
31 CHAR_PUNCT = 0x0200, // {}[]#<>%:;?*+-/^&|~!=,"'`$@()
32 };
33
34 enum {
35 CHAR_XUPPER = CHAR_XLETTER | CHAR_UPPER,
36 CHAR_XLOWER = CHAR_XLETTER | CHAR_LOWER
37 };
38 } // end namespace charinfo
39
40 /// Returns true if a byte is an ASCII character.
isASCII(char c)41 LLVM_READNONE inline bool isASCII(char c) {
42 return static_cast<unsigned char>(c) <= 127;
43 }
44
isASCII(unsigned char c)45 LLVM_READNONE inline bool isASCII(unsigned char c) { return c <= 127; }
46
47 /// Returns true if a codepoint is an ASCII character.
isASCII(uint32_t c)48 LLVM_READNONE inline bool isASCII(uint32_t c) { return c <= 127; }
isASCII(int64_t c)49 LLVM_READNONE inline bool isASCII(int64_t c) { return 0 <= c && c <= 127; }
50
51 /// Returns true if this is a valid first character of a C identifier,
52 /// which is [a-zA-Z_].
53 LLVM_READONLY inline bool isAsciiIdentifierStart(unsigned char c,
54 bool AllowDollar = false) {
55 using namespace charinfo;
56 if (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER|CHAR_UNDER))
57 return true;
58 return AllowDollar && c == '$';
59 }
60
isAsciiIdentifierContinue(unsigned char c)61 LLVM_READONLY inline bool isAsciiIdentifierContinue(unsigned char c) {
62 // Precomputed CHAR_UPPER|CHAR_LOWER|CHAR_DIGIT|CHAR_UNDER
63 static constexpr unsigned char IDContinue[256] = {
64 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
65 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
66 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,
67 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,
68 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
69 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
70 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
71 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
72 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
73 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
74 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
75 return IDContinue[c];
76 }
77
78 /// Returns true if this is a body character of a C identifier,
79 /// which is [a-zA-Z0-9_].
isAsciiIdentifierContinue(unsigned char c,bool AllowDollar)80 LLVM_READONLY inline bool isAsciiIdentifierContinue(unsigned char c,
81 bool AllowDollar) {
82 if (isAsciiIdentifierContinue(c))
83 return true;
84 return AllowDollar && c == '$';
85 }
86
87 /// Returns true if this character is horizontal ASCII whitespace:
88 /// ' ', '\\t', '\\f', '\\v'.
89 ///
90 /// Note that this returns false for '\\0'.
isHorizontalWhitespace(unsigned char c)91 LLVM_READONLY inline bool isHorizontalWhitespace(unsigned char c) {
92 using namespace charinfo;
93 return (InfoTable[c] & (CHAR_HORZ_WS|CHAR_SPACE)) != 0;
94 }
95
96 /// Returns true if this character is vertical ASCII whitespace: '\\n', '\\r'.
97 ///
98 /// Note that this returns false for '\\0'.
isVerticalWhitespace(unsigned char c)99 LLVM_READONLY inline bool isVerticalWhitespace(unsigned char c) {
100 using namespace charinfo;
101 return (InfoTable[c] & CHAR_VERT_WS) != 0;
102 }
103
104 /// Return true if this character is horizontal or vertical ASCII whitespace:
105 /// ' ', '\\t', '\\f', '\\v', '\\n', '\\r'.
106 ///
107 /// Note that this returns false for '\\0'.
isWhitespace(unsigned char c)108 LLVM_READONLY inline bool isWhitespace(unsigned char c) {
109 using namespace charinfo;
110 return (InfoTable[c] & (CHAR_HORZ_WS|CHAR_VERT_WS|CHAR_SPACE)) != 0;
111 }
112
113 /// Return true if this character is an ASCII digit: [0-9]
isDigit(unsigned char c)114 LLVM_READONLY inline bool isDigit(unsigned char c) {
115 using namespace charinfo;
116 return (InfoTable[c] & CHAR_DIGIT) != 0;
117 }
118
119 /// Return true if this character is a lowercase ASCII letter: [a-z]
isLowercase(unsigned char c)120 LLVM_READONLY inline bool isLowercase(unsigned char c) {
121 using namespace charinfo;
122 return (InfoTable[c] & CHAR_LOWER) != 0;
123 }
124
125 /// Return true if this character is an uppercase ASCII letter: [A-Z]
isUppercase(unsigned char c)126 LLVM_READONLY inline bool isUppercase(unsigned char c) {
127 using namespace charinfo;
128 return (InfoTable[c] & CHAR_UPPER) != 0;
129 }
130
131 /// Return true if this character is an ASCII letter: [a-zA-Z]
isLetter(unsigned char c)132 LLVM_READONLY inline bool isLetter(unsigned char c) {
133 using namespace charinfo;
134 return (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER)) != 0;
135 }
136
137 /// Return true if this character is an ASCII letter or digit: [a-zA-Z0-9]
isAlphanumeric(unsigned char c)138 LLVM_READONLY inline bool isAlphanumeric(unsigned char c) {
139 using namespace charinfo;
140 return (InfoTable[c] & (CHAR_DIGIT|CHAR_UPPER|CHAR_LOWER)) != 0;
141 }
142
143 /// Return true if this character is an ASCII hex digit: [0-9a-fA-F]
isHexDigit(unsigned char c)144 LLVM_READONLY inline bool isHexDigit(unsigned char c) {
145 using namespace charinfo;
146 return (InfoTable[c] & (CHAR_DIGIT|CHAR_XLETTER)) != 0;
147 }
148
149 /// Return true if this character is an ASCII punctuation character.
150 ///
151 /// Note that '_' is both a punctuation character and an identifier character!
isPunctuation(unsigned char c)152 LLVM_READONLY inline bool isPunctuation(unsigned char c) {
153 using namespace charinfo;
154 return (InfoTable[c] & (CHAR_UNDER | CHAR_PERIOD | CHAR_PUNCT)) != 0;
155 }
156
157 /// Return true if this character is an ASCII printable character; that is, a
158 /// character that should take exactly one column to print in a fixed-width
159 /// terminal.
isPrintable(unsigned char c)160 LLVM_READONLY inline bool isPrintable(unsigned char c) {
161 using namespace charinfo;
162 return (InfoTable[c] & (CHAR_UPPER | CHAR_LOWER | CHAR_PERIOD | CHAR_PUNCT |
163 CHAR_DIGIT | CHAR_UNDER | CHAR_SPACE)) != 0;
164 }
165
166 /// Return true if this is the body character of a C preprocessing number,
167 /// which is [a-zA-Z0-9_.].
isPreprocessingNumberBody(unsigned char c)168 LLVM_READONLY inline bool isPreprocessingNumberBody(unsigned char c) {
169 using namespace charinfo;
170 return (InfoTable[c] &
171 (CHAR_UPPER|CHAR_LOWER|CHAR_DIGIT|CHAR_UNDER|CHAR_PERIOD)) != 0;
172 }
173
174 /// Return true if this is the body character of a C++ raw string delimiter.
isRawStringDelimBody(unsigned char c)175 LLVM_READONLY inline bool isRawStringDelimBody(unsigned char c) {
176 using namespace charinfo;
177 return (InfoTable[c] & (CHAR_UPPER | CHAR_LOWER | CHAR_PERIOD | CHAR_DIGIT |
178 CHAR_UNDER | CHAR_PUNCT)) != 0 &&
179 c != '(' && c != ')' && c != '\\';
180 }
181
182 enum class EscapeChar {
183 Single = 1,
184 Double = 2,
185 SingleAndDouble = static_cast<int>(Single) | static_cast<int>(Double),
186 };
187
188 /// Return C-style escaped string for special characters, or an empty string if
189 /// there is no such mapping.
190 template <EscapeChar Opt, class CharT>
191 LLVM_READONLY inline auto escapeCStyle(CharT Ch) -> StringRef {
192 switch (Ch) {
193 case '\\':
194 return "\\\\";
195 case '\'':
196 if ((static_cast<int>(Opt) & static_cast<int>(EscapeChar::Single)) == 0)
197 break;
198 return "\\'";
199 case '"':
200 if ((static_cast<int>(Opt) & static_cast<int>(EscapeChar::Double)) == 0)
201 break;
202 return "\\\"";
203 case '\a':
204 return "\\a";
205 case '\b':
206 return "\\b";
207 case '\f':
208 return "\\f";
209 case '\n':
210 return "\\n";
211 case '\r':
212 return "\\r";
213 case '\t':
214 return "\\t";
215 case '\v':
216 return "\\v";
217 }
218 return {};
219 }
220
221 /// Converts the given ASCII character to its lowercase equivalent.
222 ///
223 /// If the character is not an uppercase character, it is returned as is.
toLowercase(char c)224 LLVM_READONLY inline char toLowercase(char c) {
225 if (isUppercase(c))
226 return c + 'a' - 'A';
227 return c;
228 }
229
230 /// Converts the given ASCII character to its uppercase equivalent.
231 ///
232 /// If the character is not a lowercase character, it is returned as is.
toUppercase(char c)233 LLVM_READONLY inline char toUppercase(char c) {
234 if (isLowercase(c))
235 return c + 'A' - 'a';
236 return c;
237 }
238
239
240 /// Return true if this is a valid ASCII identifier.
241 ///
242 /// Note that this is a very simple check; it does not accept UCNs as valid
243 /// identifier characters.
244 LLVM_READONLY inline bool isValidAsciiIdentifier(StringRef S,
245 bool AllowDollar = false) {
246 if (S.empty() || !isAsciiIdentifierStart(S[0], AllowDollar))
247 return false;
248
249 for (StringRef::iterator I = S.begin(), E = S.end(); I != E; ++I)
250 if (!isAsciiIdentifierContinue(*I, AllowDollar))
251 return false;
252
253 return true;
254 }
255
256 } // end namespace clang
257
258 #endif
259