From: Aki Tuomi <aki.tuomi@open-xchange.com>
Date: Tue, 11 Aug 2020 05:41:54 +0000 (+0300)
Subject: lib: macros - Add ENUM_NEGATE
X-Git-Tag: 2.3.13~81
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3698334932744c34d42878d43754d06c2a232e30;p=thirdparty%2Fdovecot%2Fcore.git

lib: macros - Add ENUM_NEGATE

Handles enumeration flag negation.
---

diff --git a/src/lib/macros.h b/src/lib/macros.h
index 6a3c7f45b1..7e67a4d16d 100644
--- a/src/lib/macros.h
+++ b/src/lib/macros.h
@@ -280,3 +280,7 @@
 # define ATTR_NO_SANITIZE_INTEGER
 # define ATTR_NO_SANITIZE_IMPLICIT_CONVERSION
 #endif
+
+/* negate enumeration flags in a way that avoids implicit conversion */
+#define ENUM_NEGATE(x) \
+	((unsigned int)(~(x)) + COMPILE_ERROR_IF_TRUE(sizeof((x)) > sizeof(int) || (x) < 0 || (x) > INT_MAX))