Implement P0457R2: 'String Prefix and Suffix Checking' for c++2a

llvm-svn: 319687

1 files changed, 104 insertions, 0 deletions

diff --git a/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp
new file mode 100644
index 00000000000..baaa4c973bb
--- /dev/null
+++ b/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp
@@ -0,0 +1,104 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// <string_view>
+
+//   constexpr bool starts_with(string_view x) const noexcept;
+
+#include <string_view>
+#include <cassert>
+
+#include "test_macros.h"
+#include "constexpr_char_traits.hpp"
+
+int main()
+{
+    {
+    typedef std::string_view SV;
+    const char *s = "abcde";
+    SV  sv0 {};
+    SV  sv1 { s, 1 };
+    SV  sv2 { s, 2 };
+//     SV  sv3 { s, 3 };
+//     SV  sv4 { s, 4 };
+//     SV  sv5 { s, 5 };
+    SV  svNot {"def", 3 };
+
+    LIBCPP_ASSERT_NOEXCEPT(sv0.starts_with(""));
+
+    assert ( sv0.starts_with(""));
+    assert (!sv0.starts_with("a"));
+
+    assert ( sv1.starts_with(""));
+    assert ( sv1.starts_with("a"));
+    assert (!sv1.starts_with("ab"));
+    assert (!sv1.starts_with("abc"));
+    assert (!sv1.starts_with("abcd"));
+    assert (!sv1.starts_with("abcde"));
+    assert (!sv1.starts_with("def"));
+
+    assert ( sv2.starts_with(s + 5));
+    assert ( sv2.starts_with("a"));
+    assert ( sv2.starts_with("ab"));
+    assert (!sv2.starts_with("abc"));
+    assert (!sv2.starts_with("abcd"));
+    assert (!sv2.starts_with("abcde"));
+    assert (!sv2.starts_with("def"));
+
+    assert ( svNot.starts_with(""));
+    assert (!svNot.starts_with("a"));
+    assert (!svNot.starts_with("ab"));
+    assert (!svNot.starts_with("abc"));
+    assert (!svNot.starts_with("abcd"));
+    assert (!svNot.starts_with("abcde"));
+    assert ( svNot.starts_with("def"));
+    }
+
+#if TEST_STD_VER > 11
+    {
+    typedef std::basic_string_view<char, constexpr_char_traits<char>> SV;
+    constexpr const char *s = "abcde";
+    constexpr SV  sv0 {};
+    constexpr SV  sv1 { s, 1 };
+    constexpr SV  sv2 { s, 2 };
+//     constexpr SV  sv3 { s, 3 };
+//     constexpr SV  sv4 { s, 4 };
+//     constexpr SV  sv5 { s, 5 };
+    constexpr SV  svNot {"def", 3 };
+
+    static_assert ( sv0.starts_with(""), "" );
+    static_assert (!sv0.starts_with("a"), "" );
+
+    static_assert ( sv1.starts_with(""), "" );
+    static_assert ( sv1.starts_with("a"), "" );
+    static_assert (!sv1.starts_with("ab"), "" );
+    static_assert (!sv1.starts_with("abc"), "" );
+    static_assert (!sv1.starts_with("abcd"), "" );
+    static_assert (!sv1.starts_with("abcde"), "" );
+    static_assert (!sv1.starts_with("def"), "" );
+
+    static_assert ( sv2.starts_with(s + 5), "" );
+    static_assert ( sv2.starts_with("a"), "" );
+    static_assert ( sv2.starts_with("ab"), "" );
+    static_assert (!sv2.starts_with("abc"), "" );
+    static_assert (!sv2.starts_with("abcd"), "" );
+    static_assert (!sv2.starts_with("abcde"), "" );
+    static_assert (!sv2.starts_with("def"), "" );
+
+    static_assert ( svNot.starts_with(""), "" );
+    static_assert (!svNot.starts_with("a"), "" );
+    static_assert (!svNot.starts_with("ab"), "" );
+    static_assert (!svNot.starts_with("abc"), "" );
+    static_assert (!svNot.starts_with("abcd"), "" );
+    static_assert (!svNot.starts_with("abcde"), "" );
+    static_assert ( svNot.starts_with("def"), "" );
+    }
+#endif
+}