From 0e14b5b3069dce8c8cc9275447105f31d707f51f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=88=98=E9=9B=A8=E5=9F=B9?= <liuyupei951018@hotmail.com>
Date: Fri, 22 Apr 2016 10:22:41 +0800
Subject: [PATCH] Add as_span(iterator start, iterator last).

---
 include/span.h       | 6 ++++++
 tests/span_tests.cpp | 5 ++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/span.h b/include/span.h
index a612983..3685143 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1688,6 +1688,12 @@ constexpr auto as_span(T* const& ptr, dim<Dimensions>... args)
             details::static_as_span_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
 }
 
+template<typename Span>
+constexpr Span as_span(contiguous_span_iterator<Span> start, contiguous_span_iterator<Span> last)
+{
+	return { &*start, static_cast<typename Span::size_type>(last - start)};
+}
+
 template <typename T>
 constexpr auto as_span(T* arr, std::ptrdiff_t len) ->
     typename details::SpanArrayTraits<T, dynamic_range>::type
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 8b39639..ef0fd44 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -1193,7 +1193,7 @@ SUITE(span_tests)
         }
 
         {
-            int a[3][4][5];
+			int a[3][4][5] = {};
             auto av = as_span(a);
             const int(*b)[4][5];
             b = a;
@@ -1209,6 +1209,9 @@ SUITE(span_tests)
             auto dv = as_span(vec);
             (void) dv;
 
+			auto av2 = as_span(av.begin(), av.end());
+			CHECK(av2 == av);
+
 #ifdef CONFIRM_COMPILATION_ERRORS
             auto dv2 = as_span(std::move(vec));
 #endif