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
diff --git a/lib/Support/Regex.cpp b/lib/Support/Regex.cpp
new file mode 100644
index 0000000..f8b2446
--- /dev/null
+++ b/lib/Support/Regex.cpp
@@ -0,0 +1,97 @@
+//===-- Regex.cpp - Regular Expression matcher implementation -------------===//
+//
+// 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/Support/Regex.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "regex_impl.h"
+#include <string>
+
+using namespace llvm;
+Regex::Regex(const StringRef ®ex, unsigned Flags)
+{
+ unsigned flags = 0;
+ preg = new struct llvm_regex;
+ preg->re_endp = regex.end();
+ if (Flags & IgnoreCase)
+ flags |= REG_ICASE;
+ if (Flags & NoSub) {
+ flags |= REG_NOSUB;
+ sub = false;
+ } else {
+ sub = true;
+ }
+ if (Flags & Newline)
+ flags |= REG_NEWLINE;
+ error = llvm_regcomp(preg, regex.data(), flags|REG_EXTENDED|REG_PEND);
+}
+
+bool Regex::isValid(std::string &Error)
+{
+ if (!error)
+ return true;
+
+ size_t len = llvm_regerror(error, preg, NULL, 0);
+ char *errbuff = new char[len];
+ llvm_regerror(error, preg, errbuff, len);
+ Error.assign(errbuff);
+ return false;
+}
+
+Regex::~Regex()
+{
+ llvm_regfree(preg);
+ delete preg;
+}
+
+bool Regex::match(const StringRef &String, SmallVectorImpl<StringRef> *Matches)
+{
+ unsigned nmatch = Matches ? preg->re_nsub+1 : 0;
+
+ if (Matches) {
+ assert(sub && "Substring matching requested but pattern compiled without");
+ Matches->clear();
+ }
+
+ // pmatch needs to have at least one element.
+ SmallVector<llvm_regmatch_t, 2> pm;
+ pm.resize(nmatch > 0 ? nmatch : 1);
+ pm[0].rm_so = 0;
+ pm[0].rm_eo = String.size();
+
+ int rc = llvm_regexec(preg, String.data(), nmatch, pm.data(), REG_STARTEND);
+
+ if (rc == REG_NOMATCH)
+ return false;
+ if (rc != 0) {
+ // regexec can fail due to invalid pattern or running out of memory.
+ error = rc;
+ return false;
+ }
+
+ // There was a match.
+
+ if (Matches) { // match position requested
+ for (unsigned i=0;i<nmatch; i++) {
+ if (pm[i].rm_so == -1) {
+ // this group didn't match
+ Matches->push_back(StringRef());
+ continue;
+ }
+ assert(pm[i].rm_eo > pm[i].rm_so);
+ Matches->push_back(StringRef(String.data()+pm[i].rm_so,
+ pm[i].rm_eo-pm[i].rm_so));
+ }
+ }
+
+ return true;
+}