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