Some more o3tl::starts/ends_with overloads

...including ones with a rest out parameter, modeled after their O(U)String
counterparts and not present in any C++ standard (so intended to stay in o3tl,
even when the C++20 wrappers are eventually removed again).  Plus test code.

These additional overloads will be used in forthcoming commits changing more
places to use std string_view.

Change-Id: Ifd05e0fdcb93e8751da22b8e4a59796ad00fe581
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122407
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

include/o3tl/string_view.hxx

@@ -15,6 +15,7 @@
 #include <cstddef>
 #include <string>
 #include <string_view>
+#include <type_traits>
 
 #include <rtl/ustring.h>
 
@@ -107,6 +108,126 @@ constexpr bool ends_with(std::basic_string_view<charT, traits> sv, charT const*
     return ends_with(sv, std::basic_string_view<charT, traits>(x));
 #endif
 }
+// The following overloads prevent deduction failures that would occur with their template
+// counterparts, when x is of a type that is implicitly convertible to basic_string_view (like
+// OString or OUString, and we only bother to provide overloads for the char and char16_t cases, not
+// also for char32_t and wchar_t, nor for C++20 char8_t):
+constexpr bool starts_with(std::string_view sv, std::string_view x) noexcept
+{
+    return starts_with<char>(sv, x);
+}
+constexpr bool starts_with(std::u16string_view sv, std::u16string_view x) noexcept
+{
+    return starts_with<char16_t>(sv, x);
+}
+constexpr bool ends_with(std::string_view sv, std::string_view x) noexcept
+{
+    return ends_with<char>(sv, x);
+}
+constexpr bool ends_with(std::u16string_view sv, std::u16string_view x) noexcept
+{
+    return ends_with<char16_t>(sv, x);
+}
+
+// Variants of C++20 std::basic_string_view::starts_with and
+// std::basic_string_view::ends_with that have a rest out parameter, similar to our OString and
+// OUString startsWith and endsWith member functions:
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool starts_with(std::basic_string_view<charT, traits> sv,
+                           std::basic_string_view<charT, traits> x,
+                           std::basic_string_view<charT, traits>* rest) noexcept
+{
+    assert(rest != nullptr);
+    auto const found = starts_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(x.length());
+    }
+    return found;
+}
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool starts_with(std::basic_string_view<charT, traits> sv, charT x,
+                           std::basic_string_view<charT, traits>* rest) noexcept
+{
+    assert(rest != nullptr);
+    auto const found = starts_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(1);
+    }
+    return found;
+}
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool starts_with(std::basic_string_view<charT, traits> sv, charT const* x,
+                           std::basic_string_view<charT, traits>* rest)
+{
+    assert(rest != nullptr);
+    auto const found = starts_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(traits::length(x));
+    }
+    return found;
+}
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool ends_with(std::basic_string_view<charT, traits> sv,
+                         std::basic_string_view<charT, traits> x,
+                         std::basic_string_view<charT, traits>* rest) noexcept
+{
+    assert(rest != nullptr);
+    auto const found = ends_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(0, sv.length() - x.length());
+    }
+    return found;
+}
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool ends_with(std::basic_string_view<charT, traits> sv, charT x,
+                         std::basic_string_view<charT, traits>* rest) noexcept
+{
+    assert(rest != nullptr);
+    auto const found = ends_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(0, sv.length() - 1);
+    }
+    return found;
+}
+template <typename charT, typename traits = std::char_traits<charT>>
+constexpr bool ends_with(std::basic_string_view<charT, traits> sv, charT const* x,
+                         std::basic_string_view<charT, traits>* rest)
+{
+    assert(rest != nullptr);
+    auto const found = ends_with(sv, x);
+    if (found)
+    {
+        *rest = sv.substr(0, sv.length() - traits::length(x));
+    }
+    return found;
+}
+// The following overloads prevent deduction failures that would occur with their template
+// counterparts, when x is of a type that is implicitly convertible to basic_string_view (like
+// OString or OUString, and we only bother to provide overloads for the char and char16_t cases, not
+// also for char32_t and wchar_t, nor for C++20 char8_t):
+constexpr bool starts_with(std::string_view sv, std::string_view x, std::string_view* rest) noexcept
+{
+    return starts_with<char>(sv, x, rest);
+}
+constexpr bool starts_with(std::u16string_view sv, std::u16string_view x,
+                           std::u16string_view* rest) noexcept
+{
+    return starts_with<char16_t>(sv, x, rest);
+}
+constexpr bool ends_with(std::string_view sv, std::string_view x, std::string_view* rest) noexcept
+{
+    return ends_with<char>(sv, x, rest);
+}
+constexpr bool ends_with(std::u16string_view sv, std::u16string_view x,
+                         std::u16string_view* rest) noexcept
+{
+    return ends_with<char16_t>(sv, x, rest);
+}
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */

o3tl/CppunitTest_o3tl_tests.mk

@@ -33,6 +33,7 @@ $(eval $(call gb_CppunitTest_add_exception_objects,o3tl_tests,\
 	o3tl/qa/test-safeint \
 	o3tl/qa/test-sorted_vector \
 	o3tl/qa/test-span \
+	o3tl/qa/test-string_view \
 	o3tl/qa/test-temporary \
 	o3tl/qa/test-typed_flags \
 	o3tl/qa/test-unit_conversion \

o3tl/qa/test-string_view.cxx

@@ -0,0 +1,591 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <sal/config.h>
+
+#include <iostream>
+#include <string_view>
+
+#include <cppunit/TestAssert.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/extensions/HelperMacros.h>
+
+#include <o3tl/string_view.hxx>
+#include <rtl/string.hxx>
+#include <rtl/ustring.hxx>
+
+namespace CppUnit
+{
+template <> struct assertion_traits<std::u16string_view>
+{
+    static bool equal(std::u16string_view x, std::u16string_view y) { return x == y; }
+
+    static std::string toString(std::u16string_view x)
+    {
+        return OUStringToOString(x, RTL_TEXTENCODING_UTF8).getStr();
+    }
+};
+}
+
+namespace
+{
+OString ostringEmpty() { return {}; } // avoid loplugin:stringview
+OString ostringDoof() { return "doof"; } // avoid loplugin:stringview
+OString ostringFoo() { return "foo"; } // avoid loplugin:stringview
+OString ostringFoobars() { return "foobars"; } // avoid loplugin:stringview
+OString ostringFood() { return "food"; } // avoid loplugin:stringview
+OString ostringOof() { return "oof"; } // avoid loplugin:stringview
+OString ostringSraboof() { return "sraboof"; } // avoid loplugin:stringview
+OUString oustringEmpty() { return {}; } // avoid loplugin:stringview
+OUString oustringDoof() { return "doof"; } // avoid loplugin:stringview
+OUString oustringFoo() { return "foo"; } // avoid loplugin:stringview
+OUString oustringFoobars() { return "foobars"; } // avoid loplugin:stringview
+OUString oustringFood() { return "food"; } // avoid loplugin:stringview
+OUString oustringOof() { return "oof"; } // avoid loplugin:stringview
+OUString oustringSraboof() { return "sraboof"; } // avoid loplugin:stringview
+
+class Test : public CppUnit::TestFixture
+{
+private:
+    CPPUNIT_TEST_SUITE(Test);
+    CPPUNIT_TEST(testStartsWith);
+    CPPUNIT_TEST(testStartsWithRest);
+    CPPUNIT_TEST(testEndsWith);
+    CPPUNIT_TEST(testEndsWithRest);
+    CPPUNIT_TEST_SUITE_END();
+
+    void testStartsWith()
+    {
+        using namespace std::string_view_literals;
+        CPPUNIT_ASSERT(o3tl::starts_with(""sv, ""sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(""sv, "foo"sv));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ""sv));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, "foo"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "food"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "foobars"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(""sv, 'f'));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, 'f'));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, 'g'));
+        CPPUNIT_ASSERT(o3tl::starts_with(""sv, ""));
+        CPPUNIT_ASSERT(!o3tl::starts_with(""sv, "foo"));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ""));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, "foo"));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "food"));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "foobars"));
+        CPPUNIT_ASSERT(o3tl::starts_with(""sv, ostringEmpty()));
+        CPPUNIT_ASSERT(!o3tl::starts_with(""sv, ostringFoo()));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ostringEmpty()));
+        CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ostringFoo()));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, ostringFood()));
+        CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, ostringFoobars()));
+        CPPUNIT_ASSERT(o3tl::starts_with(u""sv, u""sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u"foo"sv));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u""sv));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u"foo"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"food"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"foobars"sv));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u'f'));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u'f'));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u'g'));
+        CPPUNIT_ASSERT(o3tl::starts_with(u""sv, u""));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u"foo"));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u""));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u"foo"));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"food"));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"foobars"));
+        CPPUNIT_ASSERT(o3tl::starts_with(u""sv, oustringEmpty()));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, oustringFoo()));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, oustringEmpty()));
+        CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, oustringFoo()));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, oustringFood()));
+        CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, oustringFoobars()));
+    }
+
+    void testStartsWithRest()
+    {
+        using namespace std::string_view_literals;
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(""sv, ""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(""sv, "foo"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL("foobar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, "foo"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL("bar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "food"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "foobars"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(""sv, 'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, 'f', &rest));
+            CPPUNIT_ASSERT_EQUAL("oobar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, 'g', &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(""sv, "", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(""sv, "foo", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, "", &rest));
+            CPPUNIT_ASSERT_EQUAL("foobar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, "foo", &rest));
+            CPPUNIT_ASSERT_EQUAL("bar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "food", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, "foobars", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(""sv, ostringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(""sv, ostringFoo(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ostringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL("foobar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with("foobar"sv, ostringFoo(), &rest));
+            CPPUNIT_ASSERT_EQUAL("bar"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, ostringFood(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with("foobar"sv, ostringFoobars(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u""sv, u""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u"foo"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u"foobar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u"foo"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u"bar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"food"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"foobars"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(u"oobar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u'g', &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u""sv, u"", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, u"foo", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u"", &rest));
+            CPPUNIT_ASSERT_EQUAL(u"foobar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, u"foo", &rest));
+            CPPUNIT_ASSERT_EQUAL(u"bar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"food", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, u"foobars", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u""sv, oustringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u""sv, oustringFoo(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, oustringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u"foobar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::starts_with(u"foobar"sv, oustringFoo(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u"bar"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, oustringFood(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::starts_with(u"foobar"sv, oustringFoobars(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+    }
+
+    void testEndsWith()
+    {
+        using namespace std::string_view_literals;
+        CPPUNIT_ASSERT(o3tl::ends_with(""sv, ""sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(""sv, "oof"sv));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ""sv));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, "oof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "doof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "sraboof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(""sv, 'f'));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, 'f'));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, 'g'));
+        CPPUNIT_ASSERT(o3tl::ends_with(""sv, ""));
+        CPPUNIT_ASSERT(!o3tl::ends_with(""sv, "oof"));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ""));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, "oof"));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "doof"));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "sraboof"));
+        CPPUNIT_ASSERT(o3tl::ends_with(""sv, ostringEmpty()));
+        CPPUNIT_ASSERT(!o3tl::ends_with(""sv, ostringOof()));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ostringEmpty()));
+        CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ostringOof()));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, ostringDoof()));
+        CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, ostringSraboof()));
+        CPPUNIT_ASSERT(o3tl::ends_with(u""sv, u""sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u"oof"sv));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u""sv));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u"oof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"doof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"sraboof"sv));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u'f'));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u'f'));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u'g'));
+        CPPUNIT_ASSERT(o3tl::ends_with(u""sv, u""));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u"oof"));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u""));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u"oof"));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"doof"));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"sraboof"));
+        CPPUNIT_ASSERT(o3tl::ends_with(u""sv, oustringEmpty()));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, oustringOof()));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, oustringEmpty()));
+        CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, oustringOof()));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, oustringDoof()));
+        CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, oustringSraboof()));
+    }
+
+    void testEndsWithRest()
+    {
+        using namespace std::string_view_literals;
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(""sv, ""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(""sv, "oof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL("raboof"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, "oof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL("rab"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "doof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "sraboof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(""sv, 'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, 'f', &rest));
+            CPPUNIT_ASSERT_EQUAL("raboo"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, 'g', &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(""sv, "", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(""sv, "oof", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, "", &rest));
+            CPPUNIT_ASSERT_EQUAL("raboof"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, "oof", &rest));
+            CPPUNIT_ASSERT_EQUAL("rab"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "doof", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, "sraboof", &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(""sv, ostringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(""sv, ostringOof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ostringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL("raboof"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with("raboof"sv, ostringOof(), &rest));
+            CPPUNIT_ASSERT_EQUAL("rab"sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, ostringDoof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with("raboof"sv, ostringSraboof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u""sv, u""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u"oof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u""sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u"raboof"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u"oof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u"rab"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"doof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"sraboof"sv, &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u'f', &rest));
+            CPPUNIT_ASSERT_EQUAL(u"raboo"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u'g', &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u""sv, u"", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, u"oof", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u"", &rest));
+            CPPUNIT_ASSERT_EQUAL(u"raboof"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, u"oof", &rest));
+            CPPUNIT_ASSERT_EQUAL(u"rab"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"doof", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, u"sraboof", &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u""sv, oustringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u""sv, oustringOof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, oustringEmpty(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u"raboof"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(o3tl::ends_with(u"raboof"sv, oustringOof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u"rab"sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, oustringDoof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+        {
+            std::u16string_view rest;
+            CPPUNIT_ASSERT(!o3tl::ends_with(u"raboof"sv, oustringSraboof(), &rest));
+            CPPUNIT_ASSERT_EQUAL(u""sv, rest);
+        }
+    }
+};
+
+CPPUNIT_TEST_SUITE_REGISTRATION(Test);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */