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    /// Compiles the given regular expression \p Regex.
47    Regex(StringRef Regex, unsigned Flags = NoFlags);
48    Regex(const Regex &) = delete;
49    Regex &operator=(Regex regex) {
50      std::swap(preg, regex.preg);
51      std::swap(error, regex.error);
52      return *this;
53    }
54    Regex(Regex &&regex) {
55      preg = regex.preg;
56      error = regex.error;
57      regex.preg = nullptr;
58    }
59    ~Regex();
60
61    /// isValid - returns the error encountered during regex compilation, or
62    /// matching, if any.
63    bool isValid(std::string &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    /// This returns true on a successful match.
77    bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr);
78
79    /// sub - Return the result of replacing the first match of the regex in
80    /// \p String with the \p Repl string. Backreferences like "\0" in the
81    /// replacement string are replaced with the appropriate match substring.
82    ///
83    /// Note that the replacement string has backslash escaping performed on
84    /// it. Invalid backreferences are ignored (replaced by empty strings).
85    ///
86    /// \param Error If non-null, any errors in the substitution (invalid
87    /// backreferences, trailing backslashes) will be recorded as a non-empty
88    /// string.
89    std::string sub(StringRef Repl, StringRef String,
90                    std::string *Error = nullptr);
91
92    /// \brief If this function returns true, ^Str$ is an extended regular
93    /// expression that matches Str and only Str.
94    static bool isLiteralERE(StringRef Str);
95
96    /// \brief Turn String into a regex by escaping its special characters.
97    static std::string escape(StringRef String);
98
99  private:
100    struct llvm_regex *preg;
101    int error;
102  };
103}
104
105#endif // LLVM_SUPPORT_REGEX_H
106