Add regular expression matching support, based on OpenBSD regexec()/regcomp()

implementation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80493 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/Regex.h

@@ -0,0 +1,64 @@
+//===-- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+
+struct llvm_regex;
+namespace llvm {
+  class Regex {
+  public:
+    enum {
+      /// Compile with support for subgroup matches, this is just to make
+      /// constructs like Regex("...", 0) more readable as Regex("...", Sub).
+      Sub=0,
+      /// Compile for matching that ignores upper/lower case distinctions.
+      IgnoreCase=1,
+      /// Compile for matching that need only report success or failure,
+      /// not what was matched.
+      NoSub=2,
+      /// 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.
+      Newline=4
+    };
+
+    /// Compiles the given POSIX Extended Regular Expression \arg Regex.
+    /// This implementation supports regexes and matching strings with embedded
+    /// NUL characters.
+    Regex(const StringRef &Regex, unsigned Flags=NoSub);
+    ~Regex();
+
+    /// isValid - returns the error encountered during regex compilation, or
+    /// matching, if any.
+    bool isValid(std::string &Error);
+
+    /// matches - Match the regex against a given \arg String.
+    ///
+    /// \param Matches - If given, on a succesful match this will be filled in
+    /// with references to the matched group expressions (inside \arg String),
+    /// the first group is always the entire pattern.
+    /// By default the regex is compiled with NoSub, which disables support for
+    /// Matches.
+    /// For this feature to be enabled you must construct the regex using
+    /// Regex("...", Regex::Sub) constructor.
+
+    bool match(const StringRef &String, SmallVectorImpl<StringRef> *Matches=0);
+  private:
+    struct llvm_regex *preg;
+    int error;
+    bool sub;
+  };
+}