add bitflags examples to readme

untests/enum_bitflags_examples.cpp

@@ -0,0 +1,49 @@
+/*******************************************************************************
+ * This file is part of the "https://github.com/blackmatov/enum.hpp"
+ * For conditions of distribution and use, see copyright notice in LICENSE.md
+ * Copyright (C) 2019-2020, by Matvey Cherevko (blackmatov@gmail.com)
+ ******************************************************************************/
+
+#include <enum.hpp/enum_bitflags.hpp>
+
+#include "doctest/doctest.hpp"
+
+#include <string>
+#include <iostream>
+
+namespace
+{
+    enum class perms : unsigned {
+        execute = 1 << 0,
+        write = 1 << 1,
+        read = 1 << 2,
+    };
+    ENUM_HPP_OPERATORS_DECL(perms)
+}
+
+TEST_CASE("bitflags_examples") {
+    SUBCASE("Enum operators using") {
+        namespace bf = enum_hpp::bitflags;
+
+        bf::bitflags<perms> flags = perms::read | perms::write;
+
+        if ( flags.has(perms::write) ) {
+            flags.clear(perms::write);
+        }
+
+        flags.set(perms::write | perms::execute);
+
+        if ( flags & perms::execute ) {
+            flags ^= perms::execute; // flags.toggle(perms::execute);
+        }
+
+        CHECK(flags == (perms::read | perms::write));
+    }
+
+    SUBCASE("Additional bitflags functions") {
+        namespace bf = enum_hpp::bitflags;
+        bf::bitflags<perms> flags = perms::read | perms::write;
+        CHECK(bf::any_of(flags, perms::write | perms::execute));
+        CHECK(bf::any_except(flags, perms::write | perms::execute));
+    }
+}