LLVM  10.0.0svn
Regex.h
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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 <string>
20 
21 struct llvm_regex;
22 
23 namespace llvm {
24  class StringRef;
25  template<typename T> class SmallVectorImpl;
26 
27  class Regex {
28  public:
29  enum {
31  /// Compile for matching that ignores upper/lower case distinctions.
33  /// Compile for newline-sensitive matching. With this flag '[^' bracket
34  /// expressions and '.' never match newline. A ^ anchor matches the
35  /// null string after any newline in the string in addition to its normal
36  /// function, and the $ anchor matches the null string before any
37  /// newline in the string in addition to its normal function.
39  /// By default, the POSIX extended regular expression (ERE) syntax is
40  /// assumed. Pass this flag to turn on basic regular expressions (BRE)
41  /// instead.
43  };
44 
45  Regex();
46  /// Compiles the given regular expression \p Regex.
47  ///
48  /// \param Regex - referenced string is no longer needed after this
49  /// constructor does finish. Only its compiled form is kept stored.
50  Regex(StringRef Regex, unsigned Flags = NoFlags);
51  Regex(const Regex &) = delete;
52  Regex &operator=(Regex regex) {
53  std::swap(preg, regex.preg);
54  std::swap(error, regex.error);
55  return *this;
56  }
57  Regex(Regex &&regex);
58  ~Regex();
59 
60  /// isValid - returns the error encountered during regex compilation, if
61  /// any.
62  bool isValid(std::string &Error) const;
63  bool isValid() const { return !error; }
64 
65  /// getNumMatches - In a valid regex, return the number of parenthesized
66  /// matches it contains. The number filled in by match will include this
67  /// many entries plus one for the whole regex (as element 0).
68  unsigned getNumMatches() const;
69 
70  /// matches - Match the regex against a given \p String.
71  ///
72  /// \param Matches - If given, on a successful match this will be filled in
73  /// with references to the matched group expressions (inside \p String),
74  /// the first group is always the entire pattern.
75  ///
76  /// \param Error - If non-null, any errors in the matching will be recorded
77  /// as a non-empty string. If there is no error, it will be an empty string.
78  ///
79  /// This returns true on a successful match.
80  bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr,
81  std::string *Error = nullptr) const;
82 
83  /// sub - Return the result of replacing the first match of the regex in
84  /// \p String with the \p Repl string. Backreferences like "\0" in the
85  /// replacement string are replaced with the appropriate match substring.
86  ///
87  /// Note that the replacement string has backslash escaping performed on
88  /// it. Invalid backreferences are ignored (replaced by empty strings).
89  ///
90  /// \param Error If non-null, any errors in the substitution (invalid
91  /// backreferences, trailing backslashes) will be recorded as a non-empty
92  /// string. If there is no error, it will be an empty string.
93  std::string sub(StringRef Repl, StringRef String,
94  std::string *Error = nullptr) const;
95 
96  /// If this function returns true, ^Str$ is an extended regular
97  /// expression that matches Str and only Str.
98  static bool isLiteralERE(StringRef Str);
99 
100  /// Turn String into a regex by escaping its special characters.
101  static std::string escape(StringRef String);
102 
103  private:
104  struct llvm_regex *preg;
105  int error;
106  };
107 }
108 
109 #endif // LLVM_SUPPORT_REGEX_H
This class represents lattice values for constants.
Definition: AllocatorList.h:23
By default, the POSIX extended regular expression (ERE) syntax is assumed.
Definition: Regex.h:42
Compile for matching that ignores upper/lower case distinctions.
Definition: Regex.h:32
bool isValid() const
Definition: Regex.h:63
static std::string escape(StringRef String)
Turn String into a regex by escaping its special characters.
Definition: Regex.cpp:215
#define error(X)
bool match(StringRef String, SmallVectorImpl< StringRef > *Matches=nullptr, std::string *Error=nullptr) const
matches - Match the regex against a given String.
Definition: Regex.cpp:82
static bool isLiteralERE(StringRef Str)
If this function returns true, ^Str$ is an extended regular expression that matches Str and only Str...
Definition: Regex.cpp:208
Regex & operator=(Regex regex)
Definition: Regex.h:52
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:940
unsigned getNumMatches() const
getNumMatches - In a valid regex, return the number of parenthesized matches it contains.
Definition: Regex.cpp:78
std::string sub(StringRef Repl, StringRef String, std::string *Error=nullptr) const
sub - Return the result of replacing the first match of the regex in String with the Repl string...
Definition: Regex.cpp:132
Compile for newline-sensitive matching.
Definition: Regex.h:38
Lightweight error class with error context and mandatory checking.
Definition: Error.h:157
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48