Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754459AbYCLQyo (ORCPT ); Wed, 12 Mar 2008 12:54:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751797AbYCLQyg (ORCPT ); Wed, 12 Mar 2008 12:54:36 -0400 Received: from rn-out-0910.google.com ([64.233.170.184]:14470 "EHLO rn-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751695AbYCLQyg (ORCPT ); Wed, 12 Mar 2008 12:54:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date:message-id:mime-version:x-mailer:content-transfer-encoding; b=KQG9CXncEcGAanimlWwI6NeQZq5b1JjDVjgln6xKVVF+qwYC+25hRSMimJeR4k0ZeIqGO3lfgSNlC3Yc/4D2Vq/2OU3FXdqJztSlK2slONLFoPu+ams0LuhQxO2QJnwj360k3JlDNAis1EJgddlWzMEW/cWd3K4NxOnYJ7oQ+V0= Subject: Re: [PATCH 1/6] kernel: add clamp(), clamp_t() and clamp_val() macros From: Harvey Harrison To: Michael Buesch Cc: Andrew Morton , LKML , Alan Cox , Jeff Garzik , Bartlomiej Zolnierkiewicz , Mauro Carvalho Chehab In-Reply-To: <200803121613.09172.mb@bu3sch.de> References: <1205269894.22317.32.camel@brick> <200803121613.09172.mb@bu3sch.de> Content-Type: text/plain Date: Wed, 12 Mar 2008 09:54:26 -0700 Message-Id: <1205340866.8603.9.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 Content-Length: 3799 Lines: 126 On Wed, 2008-03-12 at 16:13 +0100, Michael Buesch wrote: > So why not call it clamp_const()? > One could even use __builtin_constant_p() and make clamp() use > either clamp_const() or clamp_nonconst() from above automagically. > I'd prefer that. Did you mean something like this? No more clamp_val, just clamp and clamp_t. clamp_t forces all the types, clamp looks at the min and max args, and if they are constants, uses the type of val instead. If not a constant, the strict typechecking is done. From: Harvey Harrison Subject: [PATCH] kernel: add clamp(), clamp_t() macros 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 --- include/linux/kernel.h | 68 +++++++++++++++++++++++++++++++++++------------ 1 files changed, 50 insertions(+), 18 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2df44e7..0d4cb5f 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -335,33 +335,65 @@ 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); \ + \ + if (__builtin_constant_p(min)) { \ + typeof(val) __min = (min); \ + __val = __val < __min ? __min: __val; \ + } else { \ + typeof(min) __min = (min); \ + (void) (&__val == &__min); \ + __val = __val < __min ? __min: __val; \ + } \ + \ + if (__builtin_constant_p(max)) { \ + typeof(val) __max = (max); \ + __val > __max ? __max: __val; \ + } else { \ + typeof(max) __max = (max); \ + (void) (&__val == &__max); \ + __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 -- 1.5.4.4.592.g32d4c -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/