Implement P0253R1: Fixing a design mistake in the searchers interface.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@262928 91177308-0d34-0410-b5e6-96231b3b80d8

include/algorithm

@@ -1421,20 +1421,20 @@ is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 // search
 
 template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
-_ForwardIterator1
+pair<_ForwardIterator1, _ForwardIterator1>
 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
          _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
          forward_iterator_tag, forward_iterator_tag)
 {
     if (__first2 == __last2)
-        return __first1;  // Everything matches an empty sequence
+        return make_pair(__first1, __first1);  // Everything matches an empty sequence
     while (true)
     {
         // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
         while (true)
         {
             if (__first1 == __last1)  // return __last1 if no element matches *__first2
-                return __last1;
+                return make_pair(__last1, __last1);
             if (__pred(*__first1, *__first2))
                 break;
             ++__first1;
@@ -1445,9 +1445,9 @@ __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
         while (true)
         {
             if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
-                return __first1;
+                return make_pair(__first1, __m1);
             if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
-                return __last1;
+                return make_pair(__last1, __last1);
             if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
             {
                 ++__first1;
@@ -1458,20 +1458,21 @@ __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 }
 
 template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
+_LIBCPP_CONSTEXPR_AFTER_CXX11 
+pair<_RandomAccessIterator1, _RandomAccessIterator1>
 __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
-           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
+         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
            random_access_iterator_tag, random_access_iterator_tag)
 {
-    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _D1;
+    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
-    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _D2;
+    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
     // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
-    _D2 __len2 = __last2 - __first2;
+    const _D2 __len2 = __last2 - __first2;
     if (__len2 == 0)
-        return __first1;
+        return make_pair(__first1, __first1);
-    _D1 __len1 = __last1 - __first1;
+    const _D1 __len1 = __last1 - __first1;
     if (__len1 < __len2)
-        return __last1;
+        return make_pair(__last1, __last1);
     const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
     while (true)
     {
@@ -1479,7 +1480,7 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
         while (true)
         {
             if (__first1 == __s)
-                return __last1;
+                return make_pair(__last1, __last1);
             if (__pred(*__first1, *__first2))
                 break;
             ++__first1;
@@ -1511,7 +1512,7 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
             if (__pred(*__first1, *__first2))
                 break;
         case 0:
-            return __last1;
+            return make_pair(__last1, __last1);
         }
     __phase2:
 #endif  // !_LIBCPP_UNROLL_LOOPS
@@ -1521,7 +1522,7 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
          while (true)
          {
              if (++__m2 == __last2)
-                 return __first1;
+                 return make_pair(__first1, __first1 + __len2);
              ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
              if (!__pred(*__m1, *__m2))
              {
@@ -1561,7 +1562,7 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
             if (!__pred(*__m1, *__m2))
                 break;
         case 0:
-            return __first1;
+            return make_pair(__first1, __first1 + __len2);
         }
     __continue:
         ++__first1;
@@ -1577,8 +1578,9 @@ search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 {
     return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
                          (__first1, __last1, __first2, __last2, __pred,
-                          typename std::iterator_traits<_ForwardIterator1>::iterator_category(),
+                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
-                          typename std::iterator_traits<_ForwardIterator2>::iterator_category());
+                          typename iterator_traits<_ForwardIterator2>::iterator_category())
+            .first;
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
@@ -1587,8 +1589,8 @@ _ForwardIterator1
 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
        _ForwardIterator2 __first2, _ForwardIterator2 __last2)
 {
-    typedef typename std::iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
-    typedef typename std::iterator_traits<_ForwardIterator2>::value_type __v2;
+    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
     return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
 }
 

include/experimental/algorithm

@@ -53,7 +53,7 @@ _LIBCPP_BEGIN_NAMESPACE_LFTS
 template <class _ForwardIterator, class _Searcher>
 _LIBCPP_INLINE_VISIBILITY
 _ForwardIterator search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher &__s)
-{ return __s(__f, __l); }
+{ return __s(__f, __l).first; }
 
 
 template <class _PopulationIterator, class _SampleIterator, class _Distance,

include/experimental/functional

@@ -119,9 +119,12 @@ public:
 
     template <typename _ForwardIterator2>
     _LIBCPP_INLINE_VISIBILITY
-    _ForwardIterator2 operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
+    pair<_ForwardIterator2, _ForwardIterator2>
+    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
     {
-        return _VSTD::search(__f, __l, __first_, __last_, __pred_);
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category(),
+            typename _VSTD::iterator_traits<_ForwardIterator2>::iterator_category());
     }
 
 private:
@@ -233,7 +236,7 @@ public:
         }
         
     template <typename _RandomAccessIterator2>
-    _RandomAccessIterator2 
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
     operator ()(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
     {
         static_assert ( std::is_same<
@@ -242,12 +245,12 @@ public:
                     >::value,
                 "Corpus and Pattern iterators must point to the same type" );
 
-        if (__f      == __l )    return __l; // empty corpus
+        if (__f      == __l )    return make_pair(__l, __l); // empty corpus
-        if (__first_ == __last_) return __f; // empty pattern
+        if (__first_ == __last_) return make_pair(__f, __f); // empty pattern
 
     //  If the pattern is larger than the corpus, we can't find it!
         if ( __pattern_length_ > _VSTD::distance (__f, __l)) 
-            return __l;
+            return make_pair(__l, __l);
 
     //  Do the search 
         return this->__search(__f, __l);
@@ -262,7 +265,8 @@ public: // TODO private:
     shared_ptr<vector<difference_type>>  __suffix_;
 
     template <typename _RandomAccessIterator2>
-    _RandomAccessIterator2 __search(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    __search(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
     {
         _RandomAccessIterator2 __cur = __f;
         const _RandomAccessIterator2 __last = __l - __pattern_length_;
@@ -278,7 +282,7 @@ public: // TODO private:
                 __j--;
             //  We matched - we're done!
                 if ( __j == 0 )
-                    return __cur;
+                    return make_pair(__cur, __cur + __pattern_length_);
                 }
             
         //  Since we didn't match, figure out how far to skip forward
@@ -290,7 +294,7 @@ public: // TODO private:
                 __cur += __suffix[ __j ];
         }
     
-        return __l;     // We didn't find anything
+        return make_pair(__l, __l);     // We didn't find anything
     }
 
 
@@ -384,8 +388,8 @@ public:
             }
         }
             
-     template <typename _RandomAccessIterator2>
+    template <typename _RandomAccessIterator2>
-    _RandomAccessIterator2 
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
     operator ()(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
     {
         static_assert ( std::is_same<
@@ -394,12 +398,12 @@ public:
                     >::value,
                 "Corpus and Pattern iterators must point to the same type" );
 
-        if (__f      == __l )    return __l; // empty corpus
+        if (__f      == __l )    return make_pair(__l, __l); // empty corpus
-        if (__first_ == __last_) return __f; // empty pattern
+        if (__first_ == __last_) return make_pair(__f, __f); // empty pattern
 
     //  If the pattern is larger than the corpus, we can't find it!
         if ( __pattern_length_ > _VSTD::distance (__f, __l)) 
-            return __l;
+            return make_pair(__l, __l);
 
     //  Do the search 
         return this->__search(__f, __l);
@@ -413,7 +417,8 @@ private:
     shared_ptr<skip_table_type> __skip_;
 
     template <typename _RandomAccessIterator2>
-    _RandomAccessIterator2 __search ( _RandomAccessIterator2 __f, _RandomAccessIterator2 __l ) const {
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    __search ( _RandomAccessIterator2 __f, _RandomAccessIterator2 __l ) const {
         _RandomAccessIterator2 __cur = __f;
         const _RandomAccessIterator2 __last = __l - __pattern_length_;
         const skip_table_type & __skip = *__skip_.get();
@@ -427,12 +432,12 @@ private:
                 __j--;
             //  We matched - we're done!
                 if ( __j == 0 )
-                    return __cur;
+                    return make_pair(__cur, __cur + __pattern_length_);
             }
             __cur += __skip[__cur[__pattern_length_-1]];
         }
         
-        return __l;
+        return make_pair(__l, __l);
     }
 };
 

include/string

@@ -982,7 +982,7 @@ __str_find(const _CharT *__p, _SizeT __sz,
     const _CharT* __r = 
         _VSTD::__search(__p + __pos, __p + __sz,
                         __s, __s + __n, _Traits::eq,
-                        random_access_iterator_tag(), random_access_iterator_tag());
+                        random_access_iterator_tag(), random_access_iterator_tag()).first;
     if (__r == __p + __sz)
         return __npos;
     return static_cast<_SizeT>(__r - __p);

test/std/experimental/algorithms/alg.search/search.pass.cpp

@@ -15,7 +15,7 @@
 //   ForwardIterator search(ForwardIterator first, ForwardIterator last,
 //                          const Searcher& searcher);
 //
-//		returns searcher.operator(first, last)
+//		returns searcher.operator(first, last).first
 //
 
 #include <experimental/algorithm>
@@ -27,10 +27,11 @@ int searcher_called = 0;
 
 struct MySearcher {
     template <typename Iterator>
-    Iterator operator() ( Iterator b, Iterator /*e*/) const 
+    std::pair<Iterator, Iterator>
+    operator() (Iterator b, Iterator e) const 
     {
         ++searcher_called;
-        return b;
+        return std::make_pair(b, e);
     }
 };
 

test/std/experimental/func/func.searchers/func.searchers.boyer_moore/default.pass.cpp

@@ -21,7 +21,7 @@
 //                        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pass.cpp

@@ -21,7 +21,7 @@
 //                        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pred.pass.cpp

@@ -21,7 +21,7 @@
 //                        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore/pred.pass.cpp

@@ -21,7 +21,7 @@
 //                        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/default.pass.cpp

@@ -21,7 +21,7 @@
 //                                 Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pass.cpp

@@ -21,7 +21,7 @@
 //                                 Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pred.pass.cpp

@@ -21,7 +21,7 @@
 //                                 Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/pred.pass.cpp

@@ -21,7 +21,7 @@
 //                                 Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
 // 
 //   template<class RandomAccessIterator2>
-//   RandomAccessIterator2
+//   pair<RandomAccessIterator2, RandomAccessIterator2>
 //   operator()(RandomAccessIterator2 first, RandomAccessIterator2 last) const;
 // 
 // private:

test/std/experimental/func/func.searchers/func.searchers.default/default.pass.cpp

@@ -20,7 +20,8 @@
 //         : __first_(__f), __last_(__l), __pred_(__p) {}
 // 
 //     template <typename _ForwardIterator2>
-//     _ForwardIterator2 operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const {
+//     pair<_ForwardIterator2, _ForwardIterator2>
+//     operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const {
 //         return std::search(__f, __l, __first_, __last_, __pred_);
 //         }
 // 

test/std/experimental/func/func.searchers/func.searchers.default/default.pred.pass.cpp

@@ -20,7 +20,8 @@
 //         : __first_(__f), __last_(__l), __pred_(__p) {}
 // 
 //     template <typename _ForwardIterator2>
-//     _ForwardIterator2 operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const {
+//     pair<_ForwardIterator2, _ForwardIterator2>
+//     operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const {
 //         return std::search(__f, __l, __first_, __last_, __pred_);
 //         }
 // 

www/cxx1z_status.html

@@ -86,7 +86,7 @@
 	<tr><td><a href="http://wg21.link/P0005R4">P0005R4</a></td><td>LWG</td><td>Adopt not_fn from Library Fundamentals 2 for C++17</td><td>Jacksonville</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/P0152R1">P0152R1</a></td><td>LWG</td><td>constexpr atomic::is_always_lock_free</td><td>Jacksonville</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/P0185R1">P0185R1</a></td><td>LWG</td><td>Adding [nothrow-]swappable traits</td><td>Jacksonville</td><td></td><td></td></tr>
-	<tr><td><a href="http://wg21.link/P0253R1">P0253R1</a></td><td>LWG</td><td>Fixing a design mistake in the searchers interface</td><td>Jacksonville</td><td></td><td></td></tr>
+	<tr><td><a href="http://wg21.link/P0253R1">P0253R1</a></td><td>LWG</td><td>Fixing a design mistake in the searchers interface</td><td>Jacksonville</td><td>Complete</td><td>3.9</td></tr>
 	<tr><td><a href="http://wg21.link/P0025R0">P0025R0</a></td><td>LWG</td><td>An algorithm to "clamp" a value between a pair of boundary values</td><td>Jacksonville</td><td>Complete</td><td>3.9</td></tr>
 	<tr><td><a href="http://wg21.link/P0154R1">P0154R1</a></td><td>LWG</td><td>constexpr std::hardware_{constructive,destructive}_interference_size</td><td>Jacksonville</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/P0030R1">P0030R1</a></td><td>LWG</td><td>Proposal to Introduce a 3-Argument Overload to std::hypot</td><td>Jacksonville</td><td></td><td></td></tr>