Regex.h revision 263508 
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();
49
50    /// isValid - returns the error encountered during regex compilation, or
51    /// matching, if any.
52    bool isValid(std::string &Error);
53
54    /// getNumMatches - In a valid regex, return the number of parenthesized
55    /// matches it contains.  The number filled in by match will include this
56    /// many entries plus one for the whole regex (as element 0).
57    unsigned getNumMatches() const;
58
59    /// matches - Match the regex against a given \p String.
60    ///
61    /// \param Matches - If given, on a successful match this will be filled in
62    /// with references to the matched group expressions (inside \p String),
63    /// the first group is always the entire pattern.
64    ///
65    /// This returns true on a successful match.
66    bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = 0);
67
68    /// sub - Return the result of replacing the first match of the regex in
69    /// \p String with the \p Repl string. Backreferences like "\0" in the
70    /// replacement string are replaced with the appropriate match substring.
71    ///
72    /// Note that the replacement string has backslash escaping performed on
73    /// it. Invalid backreferences are ignored (replaced by empty strings).
74    ///
75    /// \param Error If non-null, any errors in the substitution (invalid
76    /// backreferences, trailing backslashes) will be recorded as a non-empty
77    /// string.
78    std::string sub(StringRef Repl, StringRef String, std::string *Error = 0);
79
80    /// \brief If this function returns true, ^Str$ is an extended regular
81    /// expression that matches Str and only Str.
82    static bool isLiteralERE(StringRef Str);
83
84  private:
85    struct llvm_regex *preg;
86    int error;
87  };
88}
89
90#endif // LLVM_SUPPORT_REGEX_H
91