From 98445c98ebe6c65f981526fcbd0215d289cf626e Mon Sep 17 00:00:00 2001
From: Mitsuru Kariya <kariya_mitsuru@hotmail.com>
Date: Tue, 27 Aug 2013 02:16:11 +0900
Subject: [PATCH] fix equal for empty range

---
 sprout/algorithm/equal.hpp | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/sprout/algorithm/equal.hpp b/sprout/algorithm/equal.hpp
index acb09f44..5d6fe888 100644
--- a/sprout/algorithm/equal.hpp
+++ b/sprout/algorithm/equal.hpp
@@ -131,24 +131,6 @@ namespace sprout {
 			return sprout::tuples::get<2>(current) && sprout::tuples::get<0>(current) == last1 && sprout::tuples::get<1>(current) == last2;
 		}
 
-		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
-		inline SPROUT_CONSTEXPR bool
-		equal2_impl_ra(
-			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, RandomAccessIterator2 last2, BinaryPredicate pred,
-			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot
-			)
-		{
-			return pivot == 0 ? pred(*first1, *first2)
-				: sprout::detail::equal2_impl_ra(
-					first1, sprout::next(first1, pivot), first2, sprout::next(first2, pivot), pred,
-					pivot / 2
-					)
-					&& sprout::detail::equal2_impl_ra(
-						sprout::next(first1, pivot), last1, sprout::next(first2, pivot), last2, pred,
-						(sprout::distance(first1, last1) - pivot) / 2
-						)
-				;
-		}
 		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			sprout::is_constant_distance_iterator<RandomAccessIterator1>::value && sprout::is_constant_distance_iterator<RandomAccessIterator2>::value,
@@ -160,10 +142,13 @@ namespace sprout {
 			)
 		{
 			return sprout::distance(first1, last1) == sprout::distance(first2, last2)
-				&& sprout::detail::equal2_impl_ra(
-					first1, last1, first2, last2, pred,
-					sprout::distance(first1, last1) / 2
-					)
+				&& (
+					sprout::distance(first1, last1) == 0
+					|| sprout::detail::equal_impl_ra(
+						first1, last1, first2, pred,
+						sprout::distance(first1, last1) / 2
+						)
+				   )
 				;
 		}