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_RAWDEL = 0x0200, // {}[]#<>%:;?*+-/^&|~!=,"'
32 CHAR_PUNCT = 0x0400 // `$@()
33 };
34
35 enum {
36 CHAR_XUPPER = CHAR_XLETTER | CHAR_UPPER,
37 CHAR_XLOWER = CHAR_XLETTER | CHAR_LOWER
38 };
39 } // end namespace charinfo
40
41 /// Returns true if a byte is an ASCII character.
isASCII(char c)42 LLVM_READNONE inline bool isASCII(char c) {
43 return static_cast<unsigned char>(c) <= 127;
44 }
45
isASCII(unsigned char c)46 LLVM_READNONE inline bool isASCII(unsigned char c) { return c <= 127; }
47
48 /// Returns true if a codepoint is an ASCII character.
isASCII(uint32_t c)49 LLVM_READNONE inline bool isASCII(uint32_t c) { return c <= 127; }
isASCII(int64_t c)50 LLVM_READNONE inline bool isASCII(int64_t c) { return 0 <= c && c <= 127; }
51
52 /// Returns true if this is a valid first character of a C identifier,
53 /// which is [a-zA-Z_].
54 LLVM_READONLY inline bool isAsciiIdentifierStart(unsigned char c,
55 bool AllowDollar = false) {
56 using namespace charinfo;
57 if (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER|CHAR_UNDER))
58 return true;
59 return AllowDollar && c == '$';
60 }
61
62 /// Returns true if this is a body character of a C identifier,
63 /// which is [a-zA-Z0-9_].
64 LLVM_READONLY inline bool isAsciiIdentifierContinue(unsigned char c,
65 bool AllowDollar = false) {
66 using namespace charinfo;
67 if (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER|CHAR_DIGIT|CHAR_UNDER))
68 return true;
69 return AllowDollar && c == '$';
70 }
71
72 /// Returns true if this character is horizontal ASCII whitespace:
73 /// ' ', '\\t', '\\f', '\\v'.
74 ///
75 /// Note that this returns false for '\\0'.
isHorizontalWhitespace(unsigned char c)76 LLVM_READONLY inline bool isHorizontalWhitespace(unsigned char c) {
77 using namespace charinfo;
78 return (InfoTable[c] & (CHAR_HORZ_WS|CHAR_SPACE)) != 0;
79 }
80
81 /// Returns true if this character is vertical ASCII whitespace: '\\n', '\\r'.
82 ///
83 /// Note that this returns false for '\\0'.
isVerticalWhitespace(unsigned char c)84 LLVM_READONLY inline bool isVerticalWhitespace(unsigned char c) {
85 using namespace charinfo;
86 return (InfoTable[c] & CHAR_VERT_WS) != 0;
87 }
88
89 /// Return true if this character is horizontal or vertical ASCII whitespace:
90 /// ' ', '\\t', '\\f', '\\v', '\\n', '\\r'.
91 ///
92 /// Note that this returns false for '\\0'.
isWhitespace(unsigned char c)93 LLVM_READONLY inline bool isWhitespace(unsigned char c) {
94 using namespace charinfo;
95 return (InfoTable[c] & (CHAR_HORZ_WS|CHAR_VERT_WS|CHAR_SPACE)) != 0;
96 }
97
98 /// Return true if this character is an ASCII digit: [0-9]
isDigit(unsigned char c)99 LLVM_READONLY inline bool isDigit(unsigned char c) {
100 using namespace charinfo;
101 return (InfoTable[c] & CHAR_DIGIT) != 0;
102 }
103
104 /// Return true if this character is a lowercase ASCII letter: [a-z]
isLowercase(unsigned char c)105 LLVM_READONLY inline bool isLowercase(unsigned char c) {
106 using namespace charinfo;
107 return (InfoTable[c] & CHAR_LOWER) != 0;
108 }
109
110 /// Return true if this character is an uppercase ASCII letter: [A-Z]
isUppercase(unsigned char c)111 LLVM_READONLY inline bool isUppercase(unsigned char c) {
112 using namespace charinfo;
113 return (InfoTable[c] & CHAR_UPPER) != 0;
114 }
115
116 /// Return true if this character is an ASCII letter: [a-zA-Z]
isLetter(unsigned char c)117 LLVM_READONLY inline bool isLetter(unsigned char c) {
118 using namespace charinfo;
119 return (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER)) != 0;
120 }
121
122 /// Return true if this character is an ASCII letter or digit: [a-zA-Z0-9]
isAlphanumeric(unsigned char c)123 LLVM_READONLY inline bool isAlphanumeric(unsigned char c) {
124 using namespace charinfo;
125 return (InfoTable[c] & (CHAR_DIGIT|CHAR_UPPER|CHAR_LOWER)) != 0;
126 }
127
128 /// Return true if this character is an ASCII hex digit: [0-9a-fA-F]
isHexDigit(unsigned char c)129 LLVM_READONLY inline bool isHexDigit(unsigned char c) {
130 using namespace charinfo;
131 return (InfoTable[c] & (CHAR_DIGIT|CHAR_XLETTER)) != 0;
132 }
133
134 /// Return true if this character is an ASCII punctuation character.
135 ///
136 /// Note that '_' is both a punctuation character and an identifier character!
isPunctuation(unsigned char c)137 LLVM_READONLY inline bool isPunctuation(unsigned char c) {
138 using namespace charinfo;
139 return (InfoTable[c] & (CHAR_UNDER|CHAR_PERIOD|CHAR_RAWDEL|CHAR_PUNCT)) != 0;
140 }
141
142 /// Return true if this character is an ASCII printable character; that is, a
143 /// character that should take exactly one column to print in a fixed-width
144 /// terminal.
isPrintable(unsigned char c)145 LLVM_READONLY inline bool isPrintable(unsigned char c) {
146 using namespace charinfo;
147 return (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER|CHAR_PERIOD|CHAR_PUNCT|
148 CHAR_DIGIT|CHAR_UNDER|CHAR_RAWDEL|CHAR_SPACE)) != 0;
149 }
150
151 /// Return true if this is the body character of a C preprocessing number,
152 /// which is [a-zA-Z0-9_.].
isPreprocessingNumberBody(unsigned char c)153 LLVM_READONLY inline bool isPreprocessingNumberBody(unsigned char c) {
154 using namespace charinfo;
155 return (InfoTable[c] &
156 (CHAR_UPPER|CHAR_LOWER|CHAR_DIGIT|CHAR_UNDER|CHAR_PERIOD)) != 0;
157 }
158
159 /// Return true if this is the body character of a C++ raw string delimiter.
isRawStringDelimBody(unsigned char c)160 LLVM_READONLY inline bool isRawStringDelimBody(unsigned char c) {
161 using namespace charinfo;
162 return (InfoTable[c] & (CHAR_UPPER|CHAR_LOWER|CHAR_PERIOD|
163 CHAR_DIGIT|CHAR_UNDER|CHAR_RAWDEL)) != 0;
164 }
165
166 enum class EscapeChar {
167 Single = 1,
168 Double = 2,
169 SingleAndDouble = static_cast<int>(Single) | static_cast<int>(Double),
170 };
171
172 /// Return C-style escaped string for special characters, or an empty string if
173 /// there is no such mapping.
174 template <EscapeChar Opt, class CharT>
175 LLVM_READONLY inline auto escapeCStyle(CharT Ch) -> StringRef {
176 switch (Ch) {
177 case '\\':
178 return "\\\\";
179 case '\'':
180 if ((static_cast<int>(Opt) & static_cast<int>(EscapeChar::Single)) == 0)
181 break;
182 return "\\'";
183 case '"':
184 if ((static_cast<int>(Opt) & static_cast<int>(EscapeChar::Double)) == 0)
185 break;
186 return "\\\"";
187 case '\a':
188 return "\\a";
189 case '\b':
190 return "\\b";
191 case '\f':
192 return "\\f";
193 case '\n':
194 return "\\n";
195 case '\r':
196 return "\\r";
197 case '\t':
198 return "\\t";
199 case '\v':
200 return "\\v";
201 }
202 return {};
203 }
204
205 /// Converts the given ASCII character to its lowercase equivalent.
206 ///
207 /// If the character is not an uppercase character, it is returned as is.
toLowercase(char c)208 LLVM_READONLY inline char toLowercase(char c) {
209 if (isUppercase(c))
210 return c + 'a' - 'A';
211 return c;
212 }
213
214 /// Converts the given ASCII character to its uppercase equivalent.
215 ///
216 /// If the character is not a lowercase character, it is returned as is.
toUppercase(char c)217 LLVM_READONLY inline char toUppercase(char c) {
218 if (isLowercase(c))
219 return c + 'A' - 'a';
220 return c;
221 }
222
223
224 /// Return true if this is a valid ASCII identifier.
225 ///
226 /// Note that this is a very simple check; it does not accept UCNs as valid
227 /// identifier characters.
228 LLVM_READONLY inline bool isValidAsciiIdentifier(StringRef S,
229 bool AllowDollar = false) {
230 if (S.empty() || !isAsciiIdentifierStart(S[0], AllowDollar))
231 return false;
232
233 for (StringRef::iterator I = S.begin(), E = S.end(); I != E; ++I)
234 if (!isAsciiIdentifierContinue(*I, AllowDollar))
235 return false;
236
237 return true;
238 }
239
240 } // end namespace clang
241
242 #endif
243