N3158 Missing preconditions for default-constructed match_result objects

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@121282 91177308-0d34-0410-b5e6-96231b3b80d8

include/regex

@@ -208,6 +208,8 @@ public:
 
     bool matched;
 
+    constexpr sub_match();
+
     difference_type length() const;
     operator string_type() const;
     string_type str() const;
@@ -452,6 +454,8 @@ public:
     match_results& operator=(match_results&& m);
     ~match_results();
 
+    bool ready() const;
+
     // size:
     size_type size() const;
     size_type max_size() const;
@@ -4683,6 +4687,9 @@ public:
 
     bool matched;
 
+    _LIBCPP_INLINE_VISIBILITY
+    /*constexpr*/ sub_match() : matched() {}
+
     _LIBCPP_INLINE_VISIBILITY
     difference_type length() const
         {return matched ? _STD::distance(this->first, this->second) : 0;}
@@ -5104,6 +5111,7 @@ private:
     value_type __unmatched_;
     value_type __prefix_;
     value_type __suffix_;
+    bool       __ready_;
 public:
     _BidirectionalIterator __position_start_;
     typedef const value_type&                                 const_reference;
@@ -5123,6 +5131,9 @@ public:
 //    match_results& operator=(match_results&& __m) = default;
 //    ~match_results() = default;
 
+    _LIBCPP_INLINE_VISIBILITY
+    bool ready() const {return __ready_;}
+
     // size:
     _LIBCPP_INLINE_VISIBILITY
     size_type size() const {return __matches_.size();}
@@ -5224,6 +5235,7 @@ public:
         __suffix_.matched = __m.suffix().matched;
         if (!__no_update_pos)
             __position_start_ = __prefix_.first;
+        __ready_ = __m.ready();
     }
 
 private:
@@ -5254,7 +5266,8 @@ match_results<_BidirectionalIterator, _Allocator>::match_results(
       __unmatched_(),
       __prefix_(),
       __suffix_(),
-      __position_start_()
+      __position_start_(),
+      __ready_(false)
 {
 }
 
@@ -5274,6 +5287,7 @@ match_results<_BidirectionalIterator, _Allocator>::__init(unsigned __s,
     __suffix_ = __unmatched_;
     if (!__no_update_pos)
         __position_start_ = __prefix_.first;
+    __ready_ = true;
 }
 
 template <class _BidirectionalIterator, class _Allocator>
@@ -5379,6 +5393,7 @@ match_results<_BidirectionalIterator, _Allocator>::swap(match_results& __m)
     swap(__prefix_, __m.__prefix_);
     swap(__suffix_, __m.__suffix_);
     swap(__position_start_, __m.__position_start_);
+    swap(__ready_, __m.__ready_);
 }
 
 typedef match_results<const char*>             cmatch;
@@ -5391,10 +5406,13 @@ bool
 operator==(const match_results<_BidirectionalIterator, _Allocator>& __x,
            const match_results<_BidirectionalIterator, _Allocator>& __y)
 {
+    if (__x.__ready_ != __y.__ready_)
+        return false;
+    if (!__x.__ready_)
+        return true;
     return __x.__matches_ == __y.__matches_ &&
            __x.__prefix_ == __y.__prefix_ &&
-           __x.__suffix_ == __y.__suffix_ &&
-           __x.__position_start_ == __y.__position_start_;
+           __x.__suffix_ == __y.__suffix_;
 }
 
 template <class _BidirectionalIterator, class _Allocator>

test/re/re.results/re.results.state/ready.pass.cpp

@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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>
+
+// class match_results<BidirectionalIterator, Allocator>
+
+// bool ready() const;
+
+#include <regex>
+#include <cassert>
+
+void
+test1()
+{
+    std::match_results<const char*> m;
+    const char s[] = "abcdefghijk";
+    assert(m.ready() == false);
+    std::regex_search(s, m, std::regex("cd((e)fg)hi"));
+    assert(m.ready() == true);
+}
+
+void
+test2()
+{
+    std::match_results<const char*> m;
+    const char s[] = "abcdefghijk";
+    assert(m.ready() == false);
+    std::regex_search(s, m, std::regex("z"));
+    assert(m.ready() == true);
+}
+
+int main()
+{
+    test1();
+    test2();
+}

test/re/re.submatch/re.submatch.members/default.pass.cpp

@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 sub_match;
+
+// constexpr sub_match();
+
+#include <regex>
+#include <cassert>
+
+int main()
+{
+    {
+        typedef char CharT;
+        typedef std::sub_match<const CharT*> SM;
+        SM sm;
+        assert(sm.matched == false);
+    }
+    {
+        typedef wchar_t CharT;
+        typedef std::sub_match<const CharT*> SM;
+        SM sm;
+        assert(sm.matched == false);
+    }
+}