string_view: implement access API and port libcxx tests

include/libpmemobj++/string_view.hpp

@@ -11,6 +11,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <stdexcept>
 #include <string>
 
 #if __cpp_lib_string_view
@@ -53,19 +54,24 @@ class basic_string_view {
 	using pointer = value_type *;
 	using const_pointer = const value_type *;
 
-	basic_string_view() noexcept;
-	basic_string_view(const CharT *data, size_type size);
-	basic_string_view(const std::basic_string<CharT, Traits> &s);
-	basic_string_view(const CharT *data);
+	constexpr basic_string_view() noexcept;
+	constexpr basic_string_view(const CharT *data, size_type size);
+	constexpr basic_string_view(const std::basic_string<CharT, Traits> &s);
+	constexpr basic_string_view(const CharT *data);
 
-	basic_string_view(const basic_string_view &rhs) noexcept = default;
+	constexpr basic_string_view(const basic_string_view &rhs) noexcept =
+		default;
 	basic_string_view &
 	operator=(const basic_string_view &rhs) noexcept = default;
 
-	const CharT *data() const noexcept;
-	size_type size() const noexcept;
+	constexpr const CharT *data() const noexcept;
+	constexpr size_type size() const noexcept;
+	constexpr size_type length() const noexcept;
 
-	const CharT &operator[](size_type p) const noexcept;
+	const CharT &at(size_type pos) const;
+	constexpr const CharT &operator[](size_type pos) const noexcept;
+	constexpr const_reference front() const noexcept;
+	constexpr const_reference back() const noexcept;
 
 	int compare(const basic_string_view &other) const noexcept;
 
@@ -83,7 +89,7 @@ using u32string_view = basic_string_view<char32_t>;
  * Default constructor with empty data.
  */
 template <typename CharT, typename Traits>
-inline basic_string_view<CharT, Traits>::basic_string_view() noexcept
+constexpr inline basic_string_view<CharT, Traits>::basic_string_view() noexcept
     : data_(nullptr), size_(0)
 {
 }
@@ -96,8 +102,8 @@ inline basic_string_view<CharT, Traits>::basic_string_view() noexcept
  * @param[in] size length of the given data.
  */
 template <typename CharT, typename Traits>
-inline basic_string_view<CharT, Traits>::basic_string_view(const CharT *data,
-							   size_type size)
+constexpr inline basic_string_view<CharT, Traits>::basic_string_view(
+	const CharT *data, size_type size)
     : data_(data), size_(size)
 {
 }
@@ -108,7 +114,7 @@ inline basic_string_view<CharT, Traits>::basic_string_view(const CharT *data,
  * @param[in] s reference to the string to initialize with.
  */
 template <typename CharT, typename Traits>
-inline basic_string_view<CharT, Traits>::basic_string_view(
+constexpr inline basic_string_view<CharT, Traits>::basic_string_view(
 	const std::basic_string<CharT, Traits> &s)
     : data_(s.c_str()), size_(s.size())
 {
@@ -122,7 +128,8 @@ inline basic_string_view<CharT, Traits>::basic_string_view(
  *	it has to end with the terminating null character.
  */
 template <typename CharT, typename Traits>
-inline basic_string_view<CharT, Traits>::basic_string_view(const CharT *data)
+constexpr inline basic_string_view<CharT, Traits>::basic_string_view(
+	const CharT *data)
     : data_(data), size_(Traits::length(data))
 {
 }
@@ -135,7 +142,7 @@ inline basic_string_view<CharT, Traits>::basic_string_view(const CharT *data)
  *	character.
  */
 template <typename CharT, typename Traits>
-inline const CharT *
+constexpr inline const CharT *
 basic_string_view<CharT, Traits>::data() const noexcept
 {
 	return data_;
@@ -144,27 +151,80 @@ basic_string_view<CharT, Traits>::data() const noexcept
 /**
  * Returns count of characters stored in this pmem::obj::string_view data.
  *
- * @return pointer to C-like string (char *), it may not end with null
- *	character.
+ * @return the number of CharT elements in the view.
  */
 template <typename CharT, typename Traits>
-inline typename basic_string_view<CharT, Traits>::size_type
+constexpr inline typename basic_string_view<CharT, Traits>::size_type
 basic_string_view<CharT, Traits>::size() const noexcept
 {
 	return size_;
 }
 
 /**
- * Returns reference to a character at position @param[in] p .
+ * Returns count of characters stored in this pmem::obj::string_view data.
  *
- * @return reference to a char.
+ * @return the number of CharT elements in the view.
  */
 template <typename CharT, typename Traits>
-inline const CharT &basic_string_view<CharT, Traits>::operator[](size_t p) const
-	noexcept
+constexpr inline typename basic_string_view<CharT, Traits>::size_type
+basic_string_view<CharT, Traits>::length() const noexcept
+{
+	return size_;
+}
+
+/**
+ * Returns reference to a character at position @param[in] pos .
+ *
+ * @return reference to the char.
+ */
+template <typename CharT, typename Traits>
+constexpr inline const CharT &
+	basic_string_view<CharT, Traits>::operator[](size_t pos) const noexcept
+{
+	return data()[pos];
+}
+
+/**
+ * Returns reference to the character at position @param[in] pos and
+ * performs bound checking.
+ *
+ * @return reference to the char.
+ *
+ * @throw std::out_of_range when out of bounds occurs.
+ */
+template <typename CharT, typename Traits>
+inline const CharT &
+basic_string_view<CharT, Traits>::at(size_t pos) const
+{
+	if (pos >= size())
+		throw std::out_of_range("Accessing a position out of bounds!");
+	return data()[pos];
+}
+
+/**
+ * Returns reference to the last character in the view.
+ * The behavior is undefined if empty() == true.
+ *
+ * @return reference to the last character.
+ */
+template <typename CharT, typename Traits>
+constexpr inline const CharT &
+basic_string_view<CharT, Traits>::back() const noexcept
+{
+	return operator[](size() - 1);
+}
+
+/**
+ * Returns reference to the first character in the view.
+ * The behavior is undefined if empty() == true.
+ *
+ * @return reference to the first character.
+ */
+template <typename CharT, typename Traits>
+constexpr inline const CharT &
+basic_string_view<CharT, Traits>::front() const noexcept
 {
-	assert(p < size());
-	return data()[p];
+	return operator[](0);
 }
 
 /**

tests/external/CMakeLists.txt

@@ -740,6 +740,21 @@ if (TEST_STRING)
 	# XXX: port libcxx test basic_string/string.cons/initializer_list_assignment.pass
 	add_test_expect_failure(string_libcxx_string_view libcxx/basic_string/string.cons/string_view.fail.cpp)
 
+	build_test(string_libcxx_string_view_at libcxx/string.view/string.view.access/at.pass.cpp)
+	add_test_generic(NAME string_libcxx_string_view_at TRACERS none pmemcheck memcheck)
+
+	build_test(string_libcxx_string_view_back libcxx/string.view/string.view.access/back.pass.cpp)
+	add_test_generic(NAME string_libcxx_string_view_back TRACERS none pmemcheck memcheck)
+
+	build_test(string_libcxx_string_view_data libcxx/string.view/string.view.access/data.pass.cpp)
+	add_test_generic(NAME string_libcxx_string_view_data TRACERS none pmemcheck memcheck)
+
+	build_test(string_libcxx_string_view_front libcxx/string.view/string.view.access/front.pass.cpp)
+	add_test_generic(NAME string_libcxx_string_view_front TRACERS none pmemcheck memcheck)
+
+	build_test(string_libcxx_string_view_index libcxx/string.view/string.view.access/index.pass.cpp)
+	add_test_generic(NAME string_libcxx_string_view_index TRACERS none pmemcheck memcheck)
+
 	if(MSVC_VERSION GREATER_EQUAL 1920)
 		build_test(string_libcxx_string_view_opeq_string_view libcxx/string.view/string.view.comparison/opeq.string_view.string_view.pass.cpp)
 		add_test_generic(NAME string_libcxx_string_view_opeq_string_view TRACERS none pmemcheck memcheck)

tests/external/libcxx/string.view/string.view.access/at.pass.cpp

@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Copyright 2020, Intel Corporation
+//
+// Modified to test pmem::obj containers
+//
+
+// NOTE: Older versions of clang have a bug where they fail to evaluate
+// string_view::at as a constant expression.
+// XFAIL: clang-3.4, clang-3.3
+
+// <string_view>
+
+// constexpr const _CharT& at(size_type _pos) const;
+
+#include "unittest.hpp"
+
+#include <libpmemobj++/string_view.hpp>
+
+template <typename CharT>
+void
+test(const CharT *s, size_t len)
+{
+	pmem::obj::basic_string_view<CharT> sv(s, len);
+	UT_ASSERT(sv.length() == len);
+	for (size_t i = 0; i < len; ++i) {
+		UT_ASSERT(sv.at(i) == s[i]);
+		UT_ASSERT(&sv.at(i) == s + i);
+	}
+
+	try {
+		(void)sv.at(len);
+	} catch (const std::out_of_range &) {
+		return;
+	}
+	UT_ASSERT(false);
+}
+
+static void
+run()
+{
+	test("ABCDE", 5);
+	test("a", 1);
+
+	test(L"ABCDE", 5);
+	test(L"a", 1);
+
+	test(u"ABCDE", 5);
+	test(u"a", 1);
+
+	test(U"ABCDE", 5);
+	test(U"a", 1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	return run_test([&] { run(); });
+}

tests/external/libcxx/string.view/string.view.access/back.pass.cpp

@@ -0,0 +1,64 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Copyright 2020, Intel Corporation
+//
+// Modified to test pmem::obj containers
+//
+
+// <string_view>
+
+// constexpr const _CharT& front();
+
+#include "unittest.hpp"
+
+#include <libpmemobj++/string_view.hpp>
+
+template <typename CharT>
+bool
+test(const CharT *s, size_t len)
+{
+	typedef pmem::obj::basic_string_view<CharT> SV;
+	SV sv(s, len);
+
+	static_assert(std::is_same<decltype(sv.back()),
+				   typename SV::const_reference>::value,
+		      "must be const_reference");
+	static_assert(noexcept(sv.back()), "Operation must be noexcept");
+	UT_ASSERT(sv.length() == len);
+	UT_ASSERT(sv.back() == s[len - 1]);
+	return &sv.back() == s + len - 1;
+}
+
+static void
+run()
+{
+	UT_ASSERT(test("ABCDE", 5));
+	UT_ASSERT(test("a", 1));
+
+	UT_ASSERT(test(L"ABCDE", 5));
+	UT_ASSERT(test(L"a", 1));
+
+	UT_ASSERT(test(u"ABCDE", 5));
+	UT_ASSERT(test(u"a", 1));
+
+	UT_ASSERT(test(U"ABCDE", 5));
+	UT_ASSERT(test(U"a", 1));
+
+	{
+		constexpr pmem::obj::basic_string_view<char> sv("ABC", 2);
+		static_assert(sv.length() == 2, "");
+		static_assert(sv.back() == 'B', "");
+	}
+}
+
+int
+main(int argc, char *argv[])
+{
+	return run_test([&] { run(); });
+}

tests/external/libcxx/string.view/string.view.access/data.pass.cpp

@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Copyright 2020, Intel Corporation
+//
+// Modified to test pmem::obj containers
+//
+
+// <string_view>
+
+// constexpr const _CharT* data() const noexcept;
+
+#include "unittest.hpp"
+
+#include <libpmemobj++/string_view.hpp>
+
+template <typename CharT>
+void
+test(const CharT *s, size_t len)
+{
+	pmem::obj::basic_string_view<CharT> sv(s, len);
+	UT_ASSERT(sv.length() == len);
+	UT_ASSERT(sv.data() == s);
+}
+
+static void
+run()
+{
+	test("ABCDE", 5);
+	test("a", 1);
+
+	test(L"ABCDE", 5);
+	test(L"a", 1);
+
+	test(u"ABCDE", 5);
+	test(u"a", 1);
+
+	test(U"ABCDE", 5);
+	test(U"a", 1);
+
+	{
+		constexpr const char *s = "ABC";
+		constexpr pmem::obj::basic_string_view<char> sv(s, 2);
+		static_assert(sv.length() == 2, "");
+		static_assert(sv.data() == s, "");
+	}
+}
+
+int
+main(int argc, char *argv[])
+{
+	return run_test([&] { run(); });
+}