From f4ea23d3a58ee23d13b719e525e0575a29e510da Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Wed, 14 Jun 2017 04:48:45 +0000
Subject: Implement the non-parallel versions of reduce and transform_reduce
 for C++17

llvm-svn: 305365
---
 libcxx/include/numeric | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

(limited to 'libcxx/include/numeric')

diff --git a/libcxx/include/numeric b/libcxx/include/numeric
index a84fb862b66..39e81934dfa 100644
--- a/libcxx/include/numeric
+++ b/libcxx/include/numeric
@@ -25,6 +25,18 @@ template <class InputIterator, class T, class BinaryOperation>
     T
     accumulate(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);
 
+template<class InputIterator>
+    typename iterator_traits<InputIterator>::value_type
+    reduce(InputIterator first, InputIterator last);  // C++17
+
+template<class InputIterator, class T>
+    T
+    reduce(InputIterator first, InputIterator last, T init);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation>
+    T
+    reduce(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);  // C++17
+
 template <class InputIterator1, class InputIterator2, class T>
     T
     inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init);
@@ -34,6 +46,23 @@ template <class InputIterator1, class InputIterator2, class T, class BinaryOpera
     inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
                   T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);
 
+
+template<class InputIterator1, class InputIterator2, class T>
+    T
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init);  // C++17
+                     
+template<class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
+    T
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init,
+                     BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation, class UnaryOperation>
+    T
+    transform_reduce(InputIterator first, InputIterator last, T init,
+                     BinaryOperation binary_op, UnaryOperation unary_op);  // C++17
+
 template <class InputIterator, class OutputIterator>
     OutputIterator
     partial_sum(InputIterator first, InputIterator last, OutputIterator result);
@@ -114,6 +143,35 @@ accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOpe
     return __init;
 }
 
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOp __b)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, *__first);
+    return __init;
+}
+
+template <class _InputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
+{
+    return _VSTD::reduce(__first, __last, __init, _VSTD::plus<>());
+}
+
+template <class _InputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename iterator_traits<_InputIterator>::value_type
+reduce(_InputIterator __first, _InputIterator __last)
+{
+    return _VSTD::reduce(__first, __last, 
+       typename iterator_traits<_InputIterator>::value_type{});
+}
+#endif
+
 template <class _InputIterator1, class _InputIterator2, class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
 _Tp
@@ -135,6 +193,41 @@ inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2
     return __init;
 }
 
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator __first, _InputIterator __last, 
+           _Tp __init,  _BinaryOp __b, _UnaryOp __u)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, __u(*__first));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, 
+          class _Tp, class _BinaryOp1, class _BinaryOp2>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _Tp __init,  _BinaryOp1 __b1, _BinaryOp2 __b2)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2)
+        __init = __b1(__init, __b2(*__first1, *__first2));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1, 
+                 _InputIterator2 __first2, _Tp __init)
+{
+    return _VSTD::transform_reduce(__first1, __last1, __first2, __init, 
+                                   _VSTD::plus<>(), _VSTD::multiplies<>());
+}
+#endif
+
 template <class _InputIterator, class _OutputIterator>
 inline _LIBCPP_INLINE_VISIBILITY
 _OutputIterator
-- 
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