Implement <span>. Reviewed as https://reviews.llvm.org/D49338

llvm-svn: 337804

1 files changed, 136 insertions, 0 deletions

diff --git a/libcxx/test/std/containers/views/span.sub/last.pass.cpp b/libcxx/test/std/containers/views/span.sub/last.pass.cpp
new file mode 100644
index 00000000000..4e378fe549e
--- /dev/null
+++ b/libcxx/test/std/containers/views/span.sub/last.pass.cpp
@@ -0,0 +1,136 @@
+// -*- C++ -*-
+//===------------------------------ span ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 
+
+// <span>
+
+// template<ptrdiff_t Count>
+//  constexpr span<element_type, Count> last() const;
+//
+// constexpr span<element_type, dynamic_extent> last(index_type count) const;
+//
+//  Requires: 0 <= Count && Count <= size().
+
+
+#include <span>
+#include <cassert>
+#include <algorithm>
+#include <string>
+
+#include "test_macros.h"
+
+template <typename Span, ptrdiff_t Count>
+constexpr bool testConstexprSpan(Span sp)
+{
+    LIBCPP_ASSERT((noexcept(sp.template last<Count>())));
+    LIBCPP_ASSERT((noexcept(sp.last(Count))));
+    auto s1 = sp.template last<Count>();
+    auto s2 = sp.last(Count);
+    using S1 = decltype(s1);
+    using S2 = decltype(s2);
+    ASSERT_SAME_TYPE(typename Span::value_type, typename S1::value_type);
+    ASSERT_SAME_TYPE(typename Span::value_type, typename S2::value_type);
+    static_assert(S1::extent == Count, "");
+    static_assert(S2::extent == std::dynamic_extent, "");
+    return
+        s1.data() == s2.data()
+     && s1.size() == s2.size()
+     && std::equal(s1.begin(), s1.end(), sp.end() - Count);
+}
+
+
+template <typename Span, ptrdiff_t Count>
+void testRuntimeSpan(Span sp)
+{
+    LIBCPP_ASSERT((noexcept(sp.template last<Count>())));
+    LIBCPP_ASSERT((noexcept(sp.last(Count))));
+    auto s1 = sp.template last<Count>();
+    auto s2 = sp.last(Count);
+    using S1 = decltype(s1);
+    using S2 = decltype(s2);
+    ASSERT_SAME_TYPE(typename Span::value_type, typename S1::value_type);
+    ASSERT_SAME_TYPE(typename Span::value_type, typename S2::value_type);
+    static_assert(S1::extent == Count, "");
+    static_assert(S2::extent == std::dynamic_extent, "");
+    assert(s1.data() == s2.data());
+    assert(s1.size() == s2.size());
+    assert(std::equal(s1.begin(), s1.end(), sp.end() - Count));
+}
+
+
+constexpr int carr1[] = {1,2,3,4};
+          int   arr[] = {5,6,7};
+std::string   sarr [] = { "ABC", "DEF", "GHI", "JKL", "MNO"};
+
+int main ()
+{
+    {
+    using Sp = std::span<const int>;
+    static_assert(testConstexprSpan<Sp, 0>(Sp{}), "");
+
+    static_assert(testConstexprSpan<Sp, 0>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 1>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 2>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 3>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 4>(Sp{carr1}), "");
+    }
+
+    {
+    using Sp = std::span<const int, 4>;
+
+    static_assert(testConstexprSpan<Sp, 0>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 1>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 2>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 3>(Sp{carr1}), "");
+    static_assert(testConstexprSpan<Sp, 4>(Sp{carr1}), "");
+    }
+
+    {
+    using Sp = std::span<int>;
+    testRuntimeSpan<Sp, 0>(Sp{});
+
+    testRuntimeSpan<Sp, 0>(Sp{arr});
+    testRuntimeSpan<Sp, 1>(Sp{arr});
+    testRuntimeSpan<Sp, 2>(Sp{arr});
+    testRuntimeSpan<Sp, 3>(Sp{arr});
+    }
+
+    {
+    using Sp = std::span<int, 3>;
+
+    testRuntimeSpan<Sp, 0>(Sp{arr});
+    testRuntimeSpan<Sp, 1>(Sp{arr});
+    testRuntimeSpan<Sp, 2>(Sp{arr});
+    testRuntimeSpan<Sp, 3>(Sp{arr});
+    }
+
+    {
+    using Sp = std::span<std::string>;
+    testConstexprSpan<Sp, 0>(Sp{});
+    
+    testRuntimeSpan<Sp, 0>(Sp{sarr});
+    testRuntimeSpan<Sp, 1>(Sp{sarr});
+    testRuntimeSpan<Sp, 2>(Sp{sarr});
+    testRuntimeSpan<Sp, 3>(Sp{sarr});
+    testRuntimeSpan<Sp, 4>(Sp{sarr});
+    testRuntimeSpan<Sp, 5>(Sp{sarr});
+    }
+
+    {
+    using Sp = std::span<std::string, 5>;
+    
+    testRuntimeSpan<Sp, 0>(Sp{sarr});
+    testRuntimeSpan<Sp, 1>(Sp{sarr});
+    testRuntimeSpan<Sp, 2>(Sp{sarr});
+    testRuntimeSpan<Sp, 3>(Sp{sarr});
+    testRuntimeSpan<Sp, 4>(Sp{sarr});
+    testRuntimeSpan<Sp, 5>(Sp{sarr});
+    }
+}