Merge pull request #7 from m-peko/set-and-remove-flag

Support setting and removing specific flag

Author: m-peko

README.md

@@ -51,6 +51,7 @@ int main() {
     * [Bitwise Operators](#bitwise-operators)
     * [Is Specific Flag Set?](#is-specific-flag-set)
     * [All or Empty](#all-or-empty)
+    * [Set and Remove Specific Flag](#set-and-remove-specific-flag)
     * [Toggle Flags](#toggle-flags)
     * [Clear Flags](#clear-flags)
 * [Building Samples and Tests](#building-samples-and-tests)
@@ -197,6 +198,36 @@ std::cout << flags.contains(Flags::flag_b) << std::endl; // false
 std::cout << flags.is_empty() << std::endl;              // true
 ```
 
+### Set and Remove Specific Flag
+
+Not only that one can set and remove specific flag by using bitwise operators, but there are also special member functions `set` and `remove` that have the same purpose.
+
+```cpp
+struct Flags : bf::bitflags<uint32_t> {
+    using bitflags<uint32_t>::bitflags;
+
+    BITFLAG(0x00000000, none);
+    BITFLAG(0x00000001, flag_a);
+    BITFLAG(0x00000010, flag_b);
+};
+
+Flags flags = Flags::empty();
+
+std::cout << flags.contains(Flags::flag_a) << std::endl; // false
+std::cout << flags.contains(Flags::flag_b) << std::endl; // false
+
+flags.set(Flags::flag_a);
+flags.set(Flags::flag_b);
+
+std::cout << flags.contains(Flags::flag_a) << std::endl; // true
+std::cout << flags.contains(Flags::flag_b) << std::endl; // true
+
+flags.remove(Flags::flag_a);
+
+std::cout << flags.contains(Flags::flag_a) << std::endl; // false
+std::cout << flags.contains(Flags::flag_b) << std::endl; // true
+```
+
 ### Toggle Flags
 
 It is possible to toggle specific flag, i.e. if the flag is not already set, it will be set. On the other hand, if the flag is already set, it will be unset.

include/bitflags/bitflags.hpp

@@ -372,9 +372,31 @@ class bitflags {
     }
 
     /**
-     * Sets the specified flags if not already present. Otherwise, unsets the specified flags.
+     * Sets specified flag.
      *
-     * @param rhs Flags to be toggled
+     * @param rhs Flag to be set
+     */
+    constexpr void set(internal::flag<T> const& rhs) noexcept {
+        if (!contains(rhs)) {
+            curr_ ^= rhs;
+        }
+    }
+
+    /**
+     * Unsets specified flag.
+     *
+     * @param rhs Flag to be unset
+     */
+    constexpr void remove(internal::flag<T> const& rhs) noexcept {
+        if (contains(rhs)) {
+            curr_ ^= rhs;
+        }
+    }
+
+    /**
+     * Sets specified flag if not already present. Otherwise, unsets the specified flag.
+     *
+     * @param rhs Flag to be toggled
      */
     constexpr void toggle(internal::flag<T> const& rhs) noexcept {
         curr_ ^= rhs;

tests/src/bitflags_test.cpp

@@ -127,6 +127,36 @@ TEST_F(BitflagsTest, Contains) {
     EXPECT_FALSE(flags.contains(Flags::none, Flags::flag_a, Flags::flag_c));
 }
 
+TEST_F(BitflagsTest, Set) {
+    Flags flags = Flags::none;
+
+    EXPECT_FALSE(flags.contains(Flags::flag_a));
+    EXPECT_FALSE(flags.contains(Flags::flag_b));
+    EXPECT_FALSE(flags.contains(Flags::flag_c));
+
+    flags.set(Flags::flag_a);
+    flags.set(Flags::flag_b);
+
+    EXPECT_TRUE(flags.contains(Flags::flag_a));
+    EXPECT_TRUE(flags.contains(Flags::flag_b));
+    EXPECT_FALSE(flags.contains(Flags::flag_c));
+}
+
+TEST_F(BitflagsTest, Remove) {
+    Flags flags = Flags::flag_a | Flags::flag_b;
+
+    EXPECT_TRUE(flags.contains(Flags::flag_a));
+    EXPECT_TRUE(flags.contains(Flags::flag_b));
+    EXPECT_FALSE(flags.contains(Flags::flag_c));
+
+    flags.remove(Flags::flag_a);
+    flags.remove(Flags::flag_b);
+
+    EXPECT_FALSE(flags.contains(Flags::flag_a));
+    EXPECT_FALSE(flags.contains(Flags::flag_b));
+    EXPECT_FALSE(flags.contains(Flags::flag_c));
+}
+
 TEST_F(BitflagsTest, Toggle) {
     Flags flags = Flags::flag_a | Flags::flag_b;