src/llvm/include/llvm/Support/Regex.h

   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
  22 struct llvm_regex;
  23
  24 namespace 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   private:
  81     struct llvm_regex *preg;
  82     int error;
  83   };
  84 }
  85
  86 #endif // LLVM_SUPPORT_REGEX_H