1 files changed, 161 insertions, 0 deletions
diff --git a/src/rvalue_01.cpp b/src/rvalue_01.cpp
new file mode 100644
index 0000000..67a2599
--- /dev/null
+++ b/src/rvalue_01.cpp
@@ -0,0 +1,161 @@
+/*
+ * Author: Sven Gothel <[email protected]>
+ * Copyright (c) 2020 Gothel Software e.K.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <iostream>
+#include <cassert>
+#include <iterator>
+#include <string>
+#include <cctype>
+#include <atomic>
+
+class Bar {
+
+    private:
+        static std::atomic_int name_counter;
+        const int name;
+
+    public:
+        int n;
+        std::string s;
+
+        Bar()
+        : name(name_counter.fetch_add(1)), n(0), s() {
+            std::cout << "default-constructed " << name << std::endl;
+        }
+        Bar(const int i, const std::string &str)
+        : name(name_counter.fetch_add(1)), n(i), s(str) {
+            std::cout << "custom-constructed " << name << ": " << i << ", " << str << std::endl;
+        }
+
+        ~Bar() {
+            std::cout << "destructed " << name << std::endl;
+        }
+
+        Bar(const Bar &o) noexcept
+        : name(name_counter.fetch_add(1)), n(o.n), s(o.s)
+        {
+            std::cout << "copy-constructed " << name << std::endl;
+        }
+
+        Bar(Bar &&o) noexcept
+        : name(name_counter.fetch_add(1)), n(std::move(o.n)), s(std::move(o.s))
+        {
+            std::cout << "move-constructed " << name << std::endl;
+        }
+
+        Bar& operator=(Bar o) noexcept {
+            n = o.n;
+            std::swap(s, o.s);
+            std::cout << "copy-and-swap-assigned " << o.name << " -> " << name << std::endl;
+            return *this;
+        }
+
+        Bar& operator=(const Bar &o) noexcept {
+            if( &o == this ) {
+                std::cout << "copy-assigned(same) " << o.name << " -> " << name << std::endl;
+                return *this;
+            } else {
+                n = o.n;
+                s = o.s;
+                std::cout << "copy-assigned(copy) " << o.name << " -> " << name << std::endl;
+                return *this;
+            }
+        }
+
+        Bar& operator=(Bar &&o) noexcept {
+            n = o.n;
+            s = std::move(o.s);
+            std::cout << "move-assigned " << o.name << " -> " << name << std::endl;
+            return *this;
+        }
+};
+
+std::atomic_int Bar::name_counter(0);
+
+
+/** Best: Uses RVO or elision */
+Bar foo01() {
+    Bar localObj;
+    return localObj;
+}
+
+/** Best: Uses RVO or elision */
+Bar foo02(int c) {
+    if( !c ) {
+        return Bar();
+    } else {
+        return Bar();
+    }
+}
+
+
+/** Uses implicit move-ctor */
+Bar foo11(int c) {
+    Bar a, b;
+    if( !c ) {
+        return a;
+    } else {
+        return b;
+    }
+}
+
+/** Uses explicit move-ctor */
+Bar foo12(int c) {
+    Bar a, b;
+    if( !c ) {
+        return std::move(a);
+    } else {
+        return std::move(b);
+    }
+}
+
+int main() {
+    int b=1;
+    std::cout << "Block-" << b << " foo01 Start" << std::endl ;
+    {
+        Bar obj = foo01();
+    }
+    std::cout << "Block-" << (b++) << " foo01 End" << std::endl ;
+
+    std::cout << "Block-" << b << " foo02 Start" << std::endl ;
+    {
+        Bar obj = foo02(0);
+    }
+    std::cout << "Block-" << (b++) << " foo02 End" << std::endl ;
+
+    std::cout << "Block-" << b << " foo11 Start" << std::endl ;
+    {
+        Bar obj = foo11(0);
+    }
+    std::cout << "Block-" << (b++) << " foo11 End" << std::endl ;
+
+    std::cout << "Block-" << b << " foo12 Start" << std::endl ;
+    {
+        Bar obj = foo12(0);
+    }
+    std::cout << "Block-" << (b++) << " foo12 End" << std::endl ;
+
+    return 0;
+
+}