Add the C++17 extensions to std::search. Include the default searcher, but not the Boyer-Moore or Boyer-Moore-Horspool searcher (yet). BUT put the BM and BMH tests in place, marked to XFAIL. The other searchers will follow soon

llvm-svn: 322019

2 files changed, 122 insertions, 82 deletions

diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 35c6129ea50..c527860569b 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -641,6 +641,7 @@ template <class BidirectionalIterator, class Compare>
 #include <cstring>
 #include <utility> // needed to provide swap_ranges.
 #include <memory>
+#include <functional>
 #include <iterator>
 #include <cstddef>
 
@@ -1545,88 +1546,7 @@ is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 #endif
 
 // search
-
-template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
-pair<_ForwardIterator1, _ForwardIterator1>
-__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
-         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
-         forward_iterator_tag, forward_iterator_tag)
-{
-    if (__first2 == __last2)
-        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 make_pair(__last1, __last1);
-            if (__pred(*__first1, *__first2))
-                break;
-            ++__first1;
-        }
-        // *__first1 matches *__first2, now match elements after here
-        _ForwardIterator1 __m1 = __first1;
-        _ForwardIterator2 __m2 = __first2;
-        while (true)
-        {
-            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
-                return make_pair(__first1, __m1);
-            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
-                return make_pair(__last1, __last1);
-            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
-            {
-                ++__first1;
-                break;
-            }  // else there is a match, check next elements
-        }
-    }
-}
-
-template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX11
-pair<_RandomAccessIterator1, _RandomAccessIterator1>
-__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
-         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
-           random_access_iterator_tag, random_access_iterator_tag)
-{
-    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
-    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
-    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
-    const _D2 __len2 = __last2 - __first2;
-    if (__len2 == 0)
-        return make_pair(__first1, __first1);
-    const _D1 __len1 = __last1 - __first1;
-    if (__len1 < __len2)
-        return make_pair(__last1, __last1);
-    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
-
-    while (true)
-    {
-        while (true)
-        {
-            if (__first1 == __s)
-                return make_pair(__last1, __last1);
-            if (__pred(*__first1, *__first2))
-                break;
-            ++__first1;
-        }
-
-        _RandomAccessIterator1 __m1 = __first1;
-        _RandomAccessIterator2 __m2 = __first2;
-         while (true)
-         {
-             if (++__m2 == __last2)
-                 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))
-             {
-                 ++__first1;
-                 break;
-             }
-         }
-    }
-}
+// __search is in <functional>
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1652,6 +1572,14 @@ search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
     return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
 }
 
+
+#if _LIBCPP_STD_VER > 14
+template <class _ForwardIterator, class _Searcher>
+_LIBCPP_INLINE_VISIBILITY
+_ForwardIterator search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher &__s)
+{ return __s(__f, __l).first; }
+#endif
+
 // search_n
 
 template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
diff --git a/libcxx/include/functional b/libcxx/include/functional
index 3e5215b137b..abdf4516915 100644
--- a/libcxx/include/functional
+++ b/libcxx/include/functional
@@ -2411,6 +2411,118 @@ __not_fn_imp<decay_t<_RawFunc>> not_fn(_RawFunc&& __fn) {
 
 // struct hash<T*> in <memory>
 
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+pair<_ForwardIterator1, _ForwardIterator1>
+__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
+         forward_iterator_tag, forward_iterator_tag)
+{
+    if (__first2 == __last2)
+        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 make_pair(__last1, __last1);
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        }
+        // *__first1 matches *__first2, now match elements after here
+        _ForwardIterator1 __m1 = __first1;
+        _ForwardIterator2 __m2 = __first2;
+        while (true)
+        {
+            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
+                return make_pair(__first1, __m1);
+            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
+                return make_pair(__last1, __last1);
+            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
+            {
+                ++__first1;
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_RandomAccessIterator1, _RandomAccessIterator1>
+__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
+           random_access_iterator_tag, random_access_iterator_tag)
+{
+    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
+    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
+    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+    const _D2 __len2 = __last2 - __first2;
+    if (__len2 == 0)
+        return make_pair(__first1, __first1);
+    const _D1 __len1 = __last1 - __first1;
+    if (__len1 < __len2)
+        return make_pair(__last1, __last1);
+    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
+
+    while (true)
+    {
+        while (true)
+        {
+            if (__first1 == __s)
+                return make_pair(__last1, __last1);
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        }
+
+        _RandomAccessIterator1 __m1 = __first1;
+        _RandomAccessIterator2 __m2 = __first2;
+         while (true)
+         {
+             if (++__m2 == __last2)
+                 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))
+             {
+                 ++__first1;
+                 break;
+             }
+         }
+    }
+}
+
+#if _LIBCPP_STD_VER > 14
+
+// default searcher
+template<class _ForwardIterator, class _BinaryPredicate = equal_to<>>
+_LIBCPP_TYPE_VIS
+class default_searcher {
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    default_searcher(_ForwardIterator __f, _ForwardIterator __l, 
+                       _BinaryPredicate __p = _BinaryPredicate())
+        : __first_(__f), __last_(__l), __pred_(__p) {}
+
+    template <typename _ForwardIterator2>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<_ForwardIterator2, _ForwardIterator2>
+    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
+    {
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category(),
+            typename _VSTD::iterator_traits<_ForwardIterator2>::iterator_category());
+    }
+
+private:
+    _ForwardIterator __first_;
+    _ForwardIterator __last_;
+    _BinaryPredicate __pred_;
+    };
+
+#endif // _LIBCPP_STD_VER > 14
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_FUNCTIONAL