1//===-- Regex.h - Regular Expression matcher implementation -*- 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// This file implements a POSIX regular expression matcher. Both Basic and
10// Extended POSIX regular expressions (ERE) are supported. EREs were extended
11// to support backreferences in matches.
12// This implementation also supports matching strings with embedded NUL chars.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_SUPPORT_REGEX_H
17#define LLVM_SUPPORT_REGEX_H
18
19#include "llvm/ADT/BitmaskEnum.h"
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 RegexFlags : unsigned {
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 LLVM_MARK_AS_BITMASK_ENUM(BasicRegex)
46 };
47
48 Regex();
49 /// Compiles the given regular expression \p Regex.
50 ///
51 /// \param Regex - referenced string is no longer needed after this
52 /// constructor does finish. Only its compiled form is kept stored.
53 Regex(StringRef Regex, RegexFlags Flags = NoFlags);
54 Regex(StringRef Regex, unsigned Flags);
55 Regex(const Regex &) = delete;
56 Regex &operator=(Regex regex) {
57 std::swap(preg, regex.preg);
58 std::swap(error, regex.error);
59 return *this;
60 }
61 Regex(Regex &&regex);
62 ~Regex();
63
64 /// isValid - returns the error encountered during regex compilation, if
65 /// any.
66 bool isValid(std::string &Error) const;
67 bool isValid() const { return !error; }
68
69 /// getNumMatches - In a valid regex, return the number of parenthesized
70 /// matches it contains. The number filled in by match will include this
71 /// many entries plus one for the whole regex (as element 0).
72 unsigned getNumMatches() const;
73
74 /// matches - Match the regex against a given \p String.
75 ///
76 /// \param Matches - If given, on a successful match this will be filled in
77 /// with references to the matched group expressions (inside \p String),
78 /// the first group is always the entire pattern.
79 ///
80 /// \param Error - If non-null, any errors in the matching will be recorded
81 /// as a non-empty string. If there is no error, it will be an empty string.
82 ///
83 /// This returns true on a successful match.
84 bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr,
85 std::string *Error = nullptr) const;
86
87 /// sub - Return the result of replacing the first match of the regex in
88 /// \p String with the \p Repl string. Backreferences like "\0" in the
89 /// replacement string are replaced with the appropriate match substring.
90 ///
91 /// Note that the replacement string has backslash escaping performed on
92 /// it. Invalid backreferences are ignored (replaced by empty strings).
93 ///
94 /// \param Error If non-null, any errors in the substitution (invalid
95 /// backreferences, trailing backslashes) will be recorded as a non-empty
96 /// string. If there is no error, it will be an empty string.
97 std::string sub(StringRef Repl, StringRef String,
98 std::string *Error = nullptr) const;
99
100 /// If this function returns true, ^Str$ is an extended regular
101 /// expression that matches Str and only Str.
102 static bool isLiteralERE(StringRef Str);
103
104 /// Turn String into a regex by escaping its special characters.
105 static std::string escape(StringRef String);
106
107 private:
108 struct llvm_regex *preg;
109 int error;
110 };
111}
112
113#endif // LLVM_SUPPORT_REGEX_H
114