[libcxx] r186089 - Bill Fisher: This patch fixes a less likely case where '\b' can back up into invalid memory, when driven by a regex_iterator (for case 1, see r185273 or http://llvm.org/bugs/show_bug.cgi?id=16240)

Howard Hinnant hhinnant at apple.com
Thu Jul 11 08:32:55 PDT 2013


Author: hhinnant
Date: Thu Jul 11 10:32:55 2013
New Revision: 186089

URL: http://llvm.org/viewvc/llvm-project?rev=186089&view=rev
Log:
Bill Fisher: This patch fixes a less likely case where '\b' can back up into invalid memory, when driven by a regex_iterator (for case 1, see r185273 or http://llvm.org/bugs/show_bug.cgi?id=16240)

The attached test program also supplies a test for the case 1 fix in r185273.

Added:
    libcxx/trunk/test/re/re.alg/re.alg.search/backup.pass.cpp
Modified:
    libcxx/trunk/include/regex

Modified: libcxx/trunk/include/regex
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/regex?rev=186089&r1=186088&r2=186089&view=diff
==============================================================================
--- libcxx/trunk/include/regex (original)
+++ libcxx/trunk/include/regex Thu Jul 11 10:32:55 2013
@@ -5811,9 +5811,10 @@ regex_search(_BidirectionalIterator __fi
              const basic_regex<_CharT, _Traits>& __e,
              regex_constants::match_flag_type __flags = regex_constants::match_default)
 {
-    basic_string<_CharT> __s(__first, __last);
+    int __offset = (__flags & regex_constants::match_prev_avail) ? 1 : 0;
+    basic_string<_CharT> __s(_VSTD::prev(__first, __offset), __last);
     match_results<const _CharT*> __mc;
-    bool __r = __e.__search(__s.data(), __s.data() + __s.size(), __mc, __flags);
+    bool __r = __e.__search(__s.data() + __offset, __s.data() + __s.size(), __mc, __flags);
     __m.__assign(__first, __last, __mc, __flags & regex_constants::__no_update_pos);
     return __r;
 }

Added: libcxx/trunk/test/re/re.alg/re.alg.search/backup.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/re/re.alg/re.alg.search/backup.pass.cpp?rev=186089&view=auto
==============================================================================
--- libcxx/trunk/test/re/re.alg/re.alg.search/backup.pass.cpp (added)
+++ libcxx/trunk/test/re/re.alg/re.alg.search/backup.pass.cpp Thu Jul 11 10:32:55 2013
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <regex>
+
+// template <class BidirectionalIterator, class Allocator, class charT, class traits>
+//     bool
+//     regex_search(BidirectionalIterator first, BidirectionalIterator last,
+//                  match_results<BidirectionalIterator, Allocator>& m,
+//                  const basic_regex<charT, traits>& e,
+//                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+#include <regex>
+#include <string>
+#include <list>
+#include <cassert>
+
+int main()
+{
+    // This regex_iterator uses regex_search(__wrap_iter<_Iter> __first, ...)
+    // Test for http://llvm.org/bugs/show_bug.cgi?id=16240 fixed in r185273.
+    {
+        std::string s{"aaaa a"};
+        std::regex re{"\\ba"};
+        std::sregex_iterator it{s.begin(), s.end(), re};
+        std::sregex_iterator end{};
+
+        assert(it->position(0) == 0);
+        assert(it->length(0) == 1);
+
+        ++it;
+        assert(it->position(0) == 5);
+        assert(it->length(0) == 1);
+
+        ++it;
+        assert(it == end);
+    }
+
+    // This regex_iterator uses regex_search(_BidirectionalIterator __first, ...)
+    {
+        std::string s{"aaaa a"};
+        std::list<char> l{s.begin(), s.end()};
+        std::regex re{"\\ba"};
+        std::regex_iterator<std::list<char>::iterator> it{l.begin(), l.end(), re};
+        std::regex_iterator<std::list<char>::iterator> end{};
+
+        assert(it->position(0) == 0);
+        assert(it->length(0) == 1);
+
+        ++it;
+        assert(it->position(0) == 5);
+        assert(it->length(0) == 1);
+
+        ++it;
+        assert(it == end);
+    }
+}





More information about the cfe-commits mailing list