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//===-- Regex.h - Regular Expression matcher implementation -*- C++ -*-----===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file implements a POSIX regular expression matcher. Both Basic and
// Extended POSIX regular expressions (ERE) are supported. EREs were extended
// to support backreferences in matches.
// This implementation also supports matching strings with embedded NUL chars.
#include "llvm/Support/Compiler.h"
#include <string>
struct llvm_regex;
namespace llvm {
class StringRef;
template<typename T> class SmallVectorImpl;
class Regex {
enum {
/// Compile for matching that ignores upper/lower case distinctions.
/// Compile for newline-sensitive matching. With this flag '[^' bracket
/// expressions and '.' never match newline. A ^ anchor matches the
/// null string after any newline in the string in addition to its normal
/// function, and the $ anchor matches the null string before any
/// newline in the string in addition to its normal function.
/// By default, the POSIX extended regular expression (ERE) syntax is
/// assumed. Pass this flag to turn on basic regular expressions (BRE)
/// instead.
/// Compiles the given regular expression \p Regex.
Regex(StringRef Regex, unsigned Flags = NoFlags);
Regex(const Regex &) LLVM_DELETED_FUNCTION;
Regex &operator=(Regex regex) {
std::swap(preg, regex.preg);
std::swap(error, regex.error);
return *this;
Regex(Regex &&regex) {
preg = regex.preg;
error = regex.error;
regex.preg = nullptr;
/// isValid - returns the error encountered during regex compilation, or
/// matching, if any.
bool isValid(std::string &Error);
/// getNumMatches - In a valid regex, return the number of parenthesized
/// matches it contains. The number filled in by match will include this
/// many entries plus one for the whole regex (as element 0).
unsigned getNumMatches() const;
/// matches - Match the regex against a given \p String.
/// \param Matches - If given, on a successful match this will be filled in
/// with references to the matched group expressions (inside \p String),
/// the first group is always the entire pattern.
/// This returns true on a successful match.
bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr);
/// sub - Return the result of replacing the first match of the regex in
/// \p String with the \p Repl string. Backreferences like "\0" in the
/// replacement string are replaced with the appropriate match substring.
/// Note that the replacement string has backslash escaping performed on
/// it. Invalid backreferences are ignored (replaced by empty strings).
/// \param Error If non-null, any errors in the substitution (invalid
/// backreferences, trailing backslashes) will be recorded as a non-empty
/// string.
std::string sub(StringRef Repl, StringRef String,
std::string *Error = nullptr);
/// \brief If this function returns true, ^Str$ is an extended regular
/// expression that matches Str and only Str.
static bool isLiteralERE(StringRef Str);
/// \brief Turn String into a regex by escaping its special characters.
static std::string escape(StringRef String);
struct llvm_regex *preg;
int error;