From c2f85ce61b00e0014c791a764abcd162cba8a852 Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@devjustinian.com>
Date: Wed, 12 Sep 2018 20:57:15 -0700
Subject: [PATCH] Some enum_bitfield helper operators

Added:
  set += flag -> set = set | flag
  set -= flag -> set = set & ~flag
  set && flag -> (set & flag) == flag
---
 src/libraries/kutil/enum_bitfields.h | 30 ++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/src/libraries/kutil/enum_bitfields.h b/src/libraries/kutil/enum_bitfields.h
index b422190..755e521 100644
--- a/src/libraries/kutil/enum_bitfields.h
+++ b/src/libraries/kutil/enum_bitfields.h
@@ -75,6 +75,28 @@ operator ^= (E &lhs, F rhs)
 	return lhs;
 }
 
+template <typename E, typename F>
+typename std::enable_if<is_enum_bitfield<E>::value,E>::type&
+operator -= (E &lhs, F rhs)
+{
+	lhs = static_cast<E>(
+		static_cast<typename std::underlying_type<E>::type>(lhs) &
+		~static_cast<typename std::underlying_type<E>::type>(rhs));
+
+	return lhs;
+}
+
+template <typename E, typename F>
+typename std::enable_if<is_enum_bitfield<E>::value,E>::type&
+operator += (E &lhs, F rhs)
+{
+	lhs = static_cast<E>(
+		static_cast<typename std::underlying_type<E>::type>(lhs) |
+		static_cast<typename std::underlying_type<E>::type>(rhs));
+
+	return lhs;
+}
+
 template <typename E>
 typename std::enable_if<is_enum_bitfield<E>::value,bool>::type
 operator ! (E rhs)
@@ -88,3 +110,11 @@ bitfield_has(E set, E flag)
 {
 	return (set & flag) == flag;
 }
+
+// Overload the logical-and operator to be 'bitwise-and, bool-cast'
+template <typename E>
+typename std::enable_if<is_enum_bitfield<E>::value,bool>::type
+operator && (E set, E flag)
+{
+	return (set & flag) == flag;
+}