1//===-- Regex.h - Regular Expression matcher implementation -*- 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 implements a POSIX regular expression matcher. Both Basic and
11// Extended POSIX regular expressions (ERE) are supported. EREs were extended
12// to support backreferences in matches.
13// This implementation also supports matching strings with embedded NUL chars.
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_SUPPORT_REGEX_H
18#define LLVM_SUPPORT_REGEX_H
19
20#include <string>
21
22struct llvm_regex;
23
24namespace llvm {
25 class StringRef;
26 template<typename T> class SmallVectorImpl;
27
28 class Regex {
29 public:
30 enum {
31 NoFlags=0,
32 /// Compile for matching that ignores upper/lower case distinctions.
33 IgnoreCase=1,
34 /// Compile for newline-sensitive matching. With this flag '[^' bracket
35 /// expressions and '.' never match newline. A ^ anchor matches the
36 /// null string after any newline in the string in addition to its normal
37 /// function, and the $ anchor matches the null string before any
38 /// newline in the string in addition to its normal function.
39 Newline=2,
40 /// By default, the POSIX extended regular expression (ERE) syntax is
41 /// assumed. Pass this flag to turn on basic regular expressions (BRE)
42 /// instead.
43 BasicRegex=4
44 };
45
46 Regex();
47 /// Compiles the given regular expression \p Regex.
48 Regex(StringRef Regex, unsigned Flags = NoFlags);
49 Regex(const Regex &) = delete;
50 Regex &operator=(Regex regex) {
51 std::swap(preg, regex.preg);
52 std::swap(error, regex.error);
53 return *this;
54 }
55 Regex(Regex &&regex);
56 ~Regex();
57
58 /// isValid - returns the error encountered during regex compilation, or
59 /// matching, if any.
60 bool isValid(std::string &Error) const;
61
62 /// getNumMatches - In a valid regex, return the number of parenthesized
63 /// matches it contains. The number filled in by match will include this
64 /// many entries plus one for the whole regex (as element 0).
65 unsigned getNumMatches() const;
66
67 /// matches - Match the regex against a given \p String.
68 ///
69 /// \param Matches - If given, on a successful match this will be filled in
70 /// with references to the matched group expressions (inside \p String),
71 /// the first group is always the entire pattern.
72 ///
73 /// This returns true on a successful match.
74 bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr);
75
76 /// sub - Return the result of replacing the first match of the regex in
77 /// \p String with the \p Repl string. Backreferences like "\0" in the
78 /// replacement string are replaced with the appropriate match substring.
79 ///
80 /// Note that the replacement string has backslash escaping performed on
81 /// it. Invalid backreferences are ignored (replaced by empty strings).
82 ///
83 /// \param Error If non-null, any errors in the substitution (invalid
84 /// backreferences, trailing backslashes) will be recorded as a non-empty
85 /// string.
86 std::string sub(StringRef Repl, StringRef String,
87 std::string *Error = nullptr);
88
89 /// If this function returns true, ^Str$ is an extended regular
90 /// expression that matches Str and only Str.
91 static bool isLiteralERE(StringRef Str);
92
93 /// Turn String into a regex by escaping its special characters.
94 static std::string escape(StringRef String);
95
96 private:
97 struct llvm_regex *preg;
98 int error;
99 };
100}
101
102#endif // LLVM_SUPPORT_REGEX_H
103