From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756349AbbCSObF (ORCPT ); Thu, 19 Mar 2015 10:31:05 -0400 Received: from mail-we0-f171.google.com ([74.125.82.171]:36691 "EHLO mail-we0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754586AbbCSOaC (ORCPT ); Thu, 19 Mar 2015 10:30:02 -0400 From: Bartosz Golaszewski To: LKML Cc: Guenter Roeck , lm-sensors , Andrew Morton , Steven Rostedt , Bartosz Golaszewski Subject: [PATCH v3 1/4] util_macros.h: add find_closest() macro Date: Thu, 19 Mar 2015 15:30:17 +0100 Message-Id: <1426775420-31350-2-git-send-email-bgolaszewski@baylibre.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1426775420-31350-1-git-send-email-bgolaszewski@baylibre.com> References: <1426775420-31350-1-git-send-email-bgolaszewski@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Searching for the member of an array closest to 'x' is duplicated in several places. Add a new include - util_macros.h - and two macros that implement this algorithm for arrays sorted both in ascending and descending order. Signed-off-by: Bartosz Golaszewski --- include/linux/util_macros.h | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 include/linux/util_macros.h diff --git a/include/linux/util_macros.h b/include/linux/util_macros.h new file mode 100644 index 0000000..f2097ce --- /dev/null +++ b/include/linux/util_macros.h @@ -0,0 +1,39 @@ +#ifndef _LINUX_HELPER_MACROS_H_ +#define _LINUX_HELPER_MACROS_H_ + +#define __find_closest(x, a, as, op)( \ +{ \ + typeof(as) _i, _as = (as) - 1; \ + typeof(x) _x = (x); \ + typeof(*a) *_a = (a); \ + for (_i = 0; _i < _as; _i++) { \ + if (_x op DIV_ROUND_CLOSEST(_a[_i] + _a[_i + 1], 2)) \ + break; \ + } \ + (_i); \ +}) + +/* + * find_closest - locate the closest element in a sorted array + * @x: The reference value. + * @a: The array in which to look for the closest element. Must be sorted + * in ascending order. + * @as: Size of 'a'. + * + * Returns the index of the element closest to 'x'. + */ +#define find_closest(x, a, as) __find_closest(x, a, as, <=) + +/* + * find_closest_descending - locate the closest element in a sorted array + * @x: The reference value. + * @a: The array in which to look for the closest element. Must be sorted + * in descending order. + * @as: Size of 'a'. + * + * Similar to get_closest() but 'a' is expected to be sorted in descending + * order. + */ +#define find_closest_descending(x, a, as) __find_closest(x, a, as, >) + +#endif -- 2.1.4