From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: [committed] libstdc++: Fix std::match_results::end() for failed matches [PR102667]
Date: Mon, 11 Oct 2021 20:37:23 +0100 [thread overview]
Message-ID: <YWSSc6nznjEKec33@redhat.com> (raw)
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The end() function needs to consider whether the underlying vector is
empty, not whether the match_results object is empty. That's because the
underlying vector will always contain at least three elements for a
match_results object that is "ready". It contains three extra elements
which are stored in the vector but are not considered part of sequence,
and so should not be part of the [begin(),end()) range.
libstdc++-v3/ChangeLog:
PR libstdc++/102667
* include/bits/regex.h (match_result::empty()): Optimize by
calling the base function directly.
(match_results::end()): Check _Base_type::empty() not empty().
* testsuite/28_regex/match_results/102667.C: New test.
Tested powerpc64le-linux. Committed to trunk.
[-- Attachment #2: patch.txt --]
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commit 84088dc4bb6a546c896a068dc201463493babf43
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon Oct 11 09:07:15 2021
libstdc++: Fix std::match_results::end() for failed matches [PR102667]
The end() function needs to consider whether the underlying vector is
empty, not whether the match_results object is empty. That's because the
underlying vector will always contain at least three elements for a
match_results object that is "ready". It contains three extra elements
which are stored in the vector but are not considered part of sequence,
and so should not be part of the [begin(),end()) range.
libstdc++-v3/ChangeLog:
PR libstdc++/102667
* include/bits/regex.h (match_result::empty()): Optimize by
calling the base function directly.
(match_results::end()): Check _Base_type::empty() not empty().
* testsuite/28_regex/match_results/102667.C: New test.
diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index ff908da3e94..bf02bff7c49 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -1828,7 +1828,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
*/
_GLIBCXX_NODISCARD bool
empty() const noexcept
- { return size() == 0; }
+ { return _Unchecked::size() <= 3; }
///@}
@@ -1946,7 +1946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
*/
const_iterator
end() const noexcept
- { return _Base_type::end() - (empty() ? 0 : 3); }
+ { return _Base_type::end() - (_Base_type::empty() ? 0 : 3); }
/**
* @brief Gets an iterator to one-past-the-end of the collection.
diff --git a/libstdc++-v3/testsuite/28_regex/match_results/102667.C b/libstdc++-v3/testsuite/28_regex/match_results/102667.C
new file mode 100644
index 00000000000..9e38c9edaa4
--- /dev/null
+++ b/libstdc++-v3/testsuite/28_regex/match_results/102667.C
@@ -0,0 +1,39 @@
+// { dg-do run { target c++11 } }
+
+#include <regex>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ std::cmatch sm;
+ VERIFY( sm.empty() );
+ VERIFY( sm.size() == 0 );
+ VERIFY( sm.begin() == sm.end() ); // PR libstdc++/83600
+
+ bool matched = std::regex_match("a", sm, std::regex("b"));
+ VERIFY( ! matched );
+ VERIFY( sm.ready() );
+ VERIFY( sm.empty() );
+ VERIFY( sm.size() == 0 );
+ VERIFY( sm.begin() == sm.end() ); // PR libstdc++/102667
+
+ matched = std::regex_match("a", sm, std::regex("a"));
+ VERIFY( matched );
+ VERIFY( sm.ready() );
+ VERIFY( ! sm.empty() );
+ VERIFY( sm.size() == 1 );
+ VERIFY( (sm.end() - sm.begin()) == 1 );
+
+ matched = std::regex_search("abcd", sm, std::regex("(b)(c)"));
+ VERIFY( matched );
+ VERIFY( sm.ready() );
+ VERIFY( ! sm.empty() );
+ VERIFY( sm.size() == 3 );
+ VERIFY( (sm.end() - sm.begin()) == 3 );
+}
+
+int main()
+{
+ test01();
+}
reply other threads:[~2021-10-11 19:37 UTC|newest]
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