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 "llvm/ADT/BitmaskEnum.h" 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 RegexFlags : unsigned { 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 LLVM_MARK_AS_BITMASK_ENUM(BasicRegex) 46 }; 47 48 Regex(); 49 /// Compiles the given regular expression \p Regex. 50 /// 51 /// \param Regex - referenced string is no longer needed after this 52 /// constructor does finish. Only its compiled form is kept stored. 53 Regex(StringRef Regex, RegexFlags Flags = NoFlags); 54 Regex(StringRef Regex, unsigned Flags); 55 Regex(const Regex &) = delete; 56 Regex &operator=(Regex regex) { 57 std::swap(preg, regex.preg); 58 std::swap(error, regex.error); 59 return *this; 60 } 61 Regex(Regex &®ex); 62 ~Regex(); 63 64 /// isValid - returns the error encountered during regex compilation, if 65 /// any. 66 bool isValid(std::string &Error) const; isValid()67 bool isValid() const { return !error; } 68 69 /// getNumMatches - In a valid regex, return the number of parenthesized 70 /// matches it contains. The number filled in by match will include this 71 /// many entries plus one for the whole regex (as element 0). 72 unsigned getNumMatches() const; 73 74 /// matches - Match the regex against a given \p String. 75 /// 76 /// \param Matches - If given, on a successful match this will be filled in 77 /// with references to the matched group expressions (inside \p String), 78 /// the first group is always the entire pattern. 79 /// 80 /// \param Error - If non-null, any errors in the matching will be recorded 81 /// as a non-empty string. If there is no error, it will be an empty string. 82 /// 83 /// This returns true on a successful match. 84 bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr, 85 std::string *Error = nullptr) const; 86 87 /// sub - Return the result of replacing the first match of the regex in 88 /// \p String with the \p Repl string. Backreferences like "\0" in the 89 /// replacement string are replaced with the appropriate match substring. 90 /// 91 /// Note that the replacement string has backslash escaping performed on 92 /// it. Invalid backreferences are ignored (replaced by empty strings). 93 /// 94 /// \param Error If non-null, any errors in the substitution (invalid 95 /// backreferences, trailing backslashes) will be recorded as a non-empty 96 /// string. If there is no error, it will be an empty string. 97 std::string sub(StringRef Repl, StringRef String, 98 std::string *Error = nullptr) const; 99 100 /// If this function returns true, ^Str$ is an extended regular 101 /// expression that matches Str and only Str. 102 static bool isLiteralERE(StringRef Str); 103 104 /// Turn String into a regex by escaping its special characters. 105 static std::string escape(StringRef String); 106 107 private: 108 struct llvm_regex *preg; 109 int error; 110 }; 111 } 112 113 #endif // LLVM_SUPPORT_REGEX_H 114