From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760176AbYB0W0A (ORCPT ); Wed, 27 Feb 2008 17:26:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754648AbYB0WZw (ORCPT ); Wed, 27 Feb 2008 17:25:52 -0500 Received: from wa-out-1112.google.com ([209.85.146.176]:38649 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753020AbYB0WZw (ORCPT ); Wed, 27 Feb 2008 17:25:52 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:content-type:date:message-id:mime-version:x-mailer:content-transfer-encoding; b=I5PeHqn51hOoawYJU0RgTMKZ5+Hp+1Vp93DtAZGAAWuoXHpjzaD9zAd/ttmM2ydq6RzpPo11xKE/LvcqixDKzoMPxUnBHAawElObIqPLcWS1iDrReYv4tPhlKVxStulUuKsMdNSiTFNNJ3m5U9LMD8aSz8tF8Kx+t9VLAYIMh6w= Subject: [PATCH] kernel: add clamp() and clamp_t() macros From: Harvey Harrison To: Andrew Morton Cc: LKML Content-Type: text/plain Date: Wed, 27 Feb 2008 14:25:48 -0800 Message-Id: <1204151148.20280.12.camel@brick> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adds macros similar to min/max/min_t/max_t. Also, change the variable names used in the min/max macros to avoid shadowed variable warnings when min/max min_t/max_t are nested. Small formatting changes to make all the macros have a similar form. Signed-off-by: Harvey Harrison --- Andrew, here's a cleanup of the max/min macros and the introduction of a clamp/clamp_t macro. There are users for this in libata (the FIX macro you've already seen) and in drivers/media which is rolling its own. include/linux/kernel.h | 56 ++++++++++++++++++++++++++++++++--------------- 1 files changed, 38 insertions(+), 18 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2df44e7..265f0bd 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -335,33 +335,53 @@ static inline int __attribute__ ((format (printf, 1, 2))) pr_debug(const char * #endif /* __LITTLE_ENDIAN */ /* - * min()/max() macros that also do + * min()/max()/clamp() macros that also do * strict type-checking.. See the * "unnecessary" pointer comparison. */ -#define min(x,y) ({ \ - typeof(x) _x = (x); \ - typeof(y) _y = (y); \ - (void) (&_x == &_y); \ - _x < _y ? _x : _y; }) - -#define max(x,y) ({ \ - typeof(x) _x = (x); \ - typeof(y) _y = (y); \ - (void) (&_x == &_y); \ - _x > _y ? _x : _y; }) +#define min(x,y) ({ \ + typeof(x) _min1 = (x); \ + typeof(y) _min2 = (y); \ + (void) (&_min1 == &_min2); \ + _min1 < _min2 ? _min1 : _min2; }) + +#define max(x,y) ({ \ + typeof(x) _max1 = (x); \ + typeof(y) _max2 = (y); \ + (void) (&_max1 == &_max2); \ + _max1 > _max2 ? _max1 : _max2; }) + +#define clamp(val,min,max) ({ \ + typeof(val) __val = (val); \ + typeof(min) __min = (min); \ + typeof(max) __max = (max); \ + (void) (&__val == &__min); \ + (void) (&__val == &__max); \ + __val = __val < __min ? __min: __val; \ + __val > __max ? __max: __val; }) /* * ..and if you can't take the strict * types, you can specify one yourself. * - * Or not use min/max at all, of course. + * Or not use min/max/clamp at all, of course. */ -#define min_t(type,x,y) \ - ({ type __x = (x); type __y = (y); __x < __y ? __x: __y; }) -#define max_t(type,x,y) \ - ({ type __x = (x); type __y = (y); __x > __y ? __x: __y; }) - +#define min_t(type,x,y) ({ \ + type __min1 = (x); \ + type __min2 = (y); \ + __min1 < __min2 ? __min1: __min2; }) + +#define max_t(type,x,y) ({ \ + type __max1 = (x); \ + type __max2 = (y); \ + __max1 > __max2 ? __max1: __max2; }) + +#define clamp_t(type,val,min,max) ({ \ + type __val = (val); \ + type __min = (min); \ + type __max = (max); \ + __val = __val < __min ? __min: __val; \ + __val > __max ? __max: __val; }) /** * container_of - cast a member of a structure out to the containing structure -- 1.5.4.3.342.g99e8