1 //===-- Regex.h - Regular Expression matcher implementation -*- C++ -*-----===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements a POSIX regular expression matcher. Both Basic and 10 // Extended POSIX regular expressions (ERE) are supported. EREs were extended 11 // to support backreferences in matches. 12 // This implementation also supports matching strings with embedded NUL chars. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_SUPPORT_REGEX_H 17 #define LLVM_SUPPORT_REGEX_H 18 19 #include <string> 20 21 struct llvm_regex; 22 23 namespace llvm { 24 class StringRef; 25 template<typename T> class SmallVectorImpl; 26 27 class Regex { 28 public: 29 enum { 30 NoFlags=0, 31 /// Compile for matching that ignores upper/lower case distinctions. 32 IgnoreCase=1, 33 /// Compile for newline-sensitive matching. With this flag '[^' bracket 34 /// expressions and '.' never match newline. A ^ anchor matches the 35 /// null string after any newline in the string in addition to its normal 36 /// function, and the $ anchor matches the null string before any 37 /// newline in the string in addition to its normal function. 38 Newline=2, 39 /// By default, the POSIX extended regular expression (ERE) syntax is 40 /// assumed. Pass this flag to turn on basic regular expressions (BRE) 41 /// instead. 42 BasicRegex=4 43 }; 44 45 Regex(); 46 /// Compiles the given regular expression \p Regex. 47 /// 48 /// \param Regex - referenced string is no longer needed after this 49 /// constructor does finish. Only its compiled form is kept stored. 50 Regex(StringRef Regex, unsigned Flags = NoFlags); 51 Regex(const Regex &) = delete; 52 Regex &operator=(Regex regex) { 53 std::swap(preg, regex.preg); 54 std::swap(error, regex.error); 55 return *this; 56 } 57 Regex(Regex &®ex); 58 ~Regex(); 59 60 /// isValid - returns the error encountered during regex compilation, if 61 /// any. 62 bool isValid(std::string &Error) const; isValid()63 bool isValid() const { return !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 /// \param Error - If non-null, any errors in the matching will be recorded 77 /// as a non-empty string. If there is no error, it will be an empty string. 78 /// 79 /// This returns true on a successful match. 80 bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr, 81 std::string *Error = nullptr) const; 82 83 /// sub - Return the result of replacing the first match of the regex in 84 /// \p String with the \p Repl string. Backreferences like "\0" in the 85 /// replacement string are replaced with the appropriate match substring. 86 /// 87 /// Note that the replacement string has backslash escaping performed on 88 /// it. Invalid backreferences are ignored (replaced by empty strings). 89 /// 90 /// \param Error If non-null, any errors in the substitution (invalid 91 /// backreferences, trailing backslashes) will be recorded as a non-empty 92 /// string. If there is no error, it will be an empty string. 93 std::string sub(StringRef Repl, StringRef String, 94 std::string *Error = nullptr) const; 95 96 /// If this function returns true, ^Str$ is an extended regular 97 /// expression that matches Str and only Str. 98 static bool isLiteralERE(StringRef Str); 99 100 /// Turn String into a regex by escaping its special characters. 101 static std::string escape(StringRef String); 102 103 private: 104 struct llvm_regex *preg; 105 int error; 106 }; 107 } 108 109 #endif // LLVM_SUPPORT_REGEX_H 110