From: Sean Anderson <seanga2@gmail.com>
Date: Wed, 24 Nov 2021 18:26:13 +0000 (-0500)
Subject: include/c: Add abs_diff macro
X-Git-Tag: v2.38-rc1~118
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=adc21ee18fb8af79adaf9d4254ab0f935e38f784;p=thirdparty%2Futil-linux.git

include/c: Add abs_diff macro

This macro calculates abs(a - b). It is especially useful for unsigned
numbers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

diff --git a/include/c.h b/include/c.h
index 354b59e299..ba799d8fd3 100644
--- a/include/c.h
+++ b/include/c.h
@@ -159,6 +159,14 @@
 	_max1 > _max2 ? _max1 : _max2; })
 #endif
 
+#ifndef abs_diff
+# define abs_diff(x, y) __extension__ ({        \
+	__typeof__(x) _a = (x);			\
+	__typeof__(y) _b = (y);			\
+	(void) (&_a == &_b);			\
+	_a > _b ? _a - _b : _b - _a; })
+#endif
+
 #ifndef cmp_numbers
 # define cmp_numbers(x, y) __extension__ ({	\
 	__typeof__(x) _a = (x);			\