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       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             :     Regex();
      47             :     /// Compiles the given regular expression \p Regex.
      48             :     Regex(StringRef Regex, unsigned Flags = NoFlags);
      49             :     Regex(const Regex &) = delete;
      50             :     Regex &operator=(Regex regex) {
      51           4 :       std::swap(preg, regex.preg);
      52           4 :       std::swap(error, regex.error);
      53             :       return *this;
      54             :     }
      55             :     Regex(Regex &&regex);
      56             :     ~Regex();
      57             : 
      58             :     /// isValid - returns the error encountered during regex compilation, or
      59             :     /// matching, if any.
      60             :     bool isValid(std::string &Error) const;
      61             : 
      62             :     /// getNumMatches - In a valid regex, return the number of parenthesized
      63             :     /// matches it contains.  The number filled in by match will include this
      64             :     /// many entries plus one for the whole regex (as element 0).
      65             :     unsigned getNumMatches() const;
      66             : 
      67             :     /// matches - Match the regex against a given \p String.
      68             :     ///
      69             :     /// \param Matches - If given, on a successful match this will be filled in
      70             :     /// with references to the matched group expressions (inside \p String),
      71             :     /// the first group is always the entire pattern.
      72             :     ///
      73             :     /// This returns true on a successful match.
      74             :     bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr);
      75             : 
      76             :     /// sub - Return the result of replacing the first match of the regex in
      77             :     /// \p String with the \p Repl string. Backreferences like "\0" in the
      78             :     /// replacement string are replaced with the appropriate match substring.
      79             :     ///
      80             :     /// Note that the replacement string has backslash escaping performed on
      81             :     /// it. Invalid backreferences are ignored (replaced by empty strings).
      82             :     ///
      83             :     /// \param Error If non-null, any errors in the substitution (invalid
      84             :     /// backreferences, trailing backslashes) will be recorded as a non-empty
      85             :     /// string.
      86             :     std::string sub(StringRef Repl, StringRef String,
      87             :                     std::string *Error = nullptr);
      88             : 
      89             :     /// \brief If this function returns true, ^Str$ is an extended regular
      90             :     /// expression that matches Str and only Str.
      91             :     static bool isLiteralERE(StringRef Str);
      92             : 
      93             :     /// \brief Turn String into a regex by escaping its special characters.
      94             :     static std::string escape(StringRef String);
      95             : 
      96             :   private:
      97             :     struct llvm_regex *preg;
      98             :     int error;
      99             :   };
     100             : }
     101             : 
     102             : #endif // LLVM_SUPPORT_REGEX_H