From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID shortcircuit=no autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id A94231F405 for ; Thu, 9 Aug 2018 21:44:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727318AbeHJALH (ORCPT ); Thu, 9 Aug 2018 20:11:07 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:40659 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727290AbeHJALH (ORCPT ); Thu, 9 Aug 2018 20:11:07 -0400 Received: by mail-wr1-f68.google.com with SMTP id h15-v6so6424502wrs.7 for ; Thu, 09 Aug 2018 14:44:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version; bh=E/DXg6eEPloEt0mPsa3y20wkVgAEM88vP7M63Pivn/g=; b=P3ohJMs5GWu4mqa1rWW76BVcazftuRMXdN/8Flo5h98uggJmyBg1xWq9Ok99mZu/DQ 3hWjLizrNWLJMnOhgR9mayXuAJhmeayCYCcsXkAZeoAPTsCCZv4pyTtdPv0reC/OI2m7 8bt5+Cf339L4cOGbWGkgcaSs7zOd75l7+RplGNR3vFGuOWBWTN239N7UQi49kXDpQ38k xIiMxjUEZQUGwx+/8iPiIIs2zCra2Rve5d6wvyQE2OBvcPU4W7vq/nGaUjzZybbiMENp byEDWkgMSlDbma6WWb5a+1EHPlOZCPFs84/KG3HQsTN8HzTnPqokhl9oSySc5254izUx udww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:references:date :in-reply-to:message-id:user-agent:mime-version; bh=E/DXg6eEPloEt0mPsa3y20wkVgAEM88vP7M63Pivn/g=; b=iJYjuyUikgE5iDjhi0A2jcbaSlN0CVK2wRaXLYjbSW6LYu3ToS/ppDkaRolnZMSeSX 1rKxZdA06mTKn0HSnchuxXsHh0Fzx8oVKKLdUw4brjwLiHW0RzcJ/Nep3g4Z1iGYQxEl wt2a+OQT3AF0p4T57zt31Q15gUkARUS1eWEl2b3vubBz8nbcQUDh4mQdGv1o6cbkn4kq ew/sjZo6UL3L8i44eAdaRbnvmPzIki+ZwnsiUneJbsJ/OKKR4bCC9BnOl9qnKsfEM3j5 nTSoOU3omOaEcJk5NIhdM//8+THdRUlEe/PM+kbtmqfLxISe9sYF89YJZbhNgmi+NkOB GM4g== X-Gm-Message-State: AOUpUlEexBbtzKoNJOqdofGsVwfdDgYw7+OdwOpZCmAJCjFeZCXCkYEV O25Do55y48x8RpFdBaUBccg= X-Google-Smtp-Source: AA+uWPwwfy1ZzJOanX6EKi+HhvmFpvfXk0Cm+xgpJosX04P0ewbUvkXp33Sqy2gYiKMVLGjRLd9aUA== X-Received: by 2002:a5d:5385:: with SMTP id d5-v6mr2427127wrv.151.1533851061379; Thu, 09 Aug 2018 14:44:21 -0700 (PDT) Received: from localhost (112.68.155.104.bc.googleusercontent.com. [104.155.68.112]) by smtp.gmail.com with ESMTPSA id 200-v6sm15928092wmv.6.2018.08.09.14.44.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 Aug 2018 14:44:20 -0700 (PDT) From: Junio C Hamano To: Stefan Beller Cc: git@vger.kernel.org, hvoigt@hvoigt.net Subject: Re: [PATCH 03/10] sha1-array: provide oid_array_remove_if References: <20180808221752.195419-1-sbeller@google.com> <20180808221752.195419-4-sbeller@google.com> Date: Thu, 09 Aug 2018 14:44:20 -0700 In-Reply-To: <20180808221752.195419-4-sbeller@google.com> (Stefan Beller's message of "Wed, 8 Aug 2018 15:17:45 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Stefan Beller writes: > Signed-off-by: Stefan Beller > --- > sha1-array.c | 39 +++++++++++++++++++++++++++++++++++++++ > sha1-array.h | 3 +++ > 2 files changed, 42 insertions(+) > > diff --git a/sha1-array.c b/sha1-array.c > index 265941fbf40..10eb08b425e 100644 > --- a/sha1-array.c > +++ b/sha1-array.c > @@ -77,3 +77,42 @@ int oid_array_for_each_unique(struct oid_array *array, > } > return 0; > } > + > +int oid_array_remove_if(struct oid_array *array, > + for_each_oid_fn fn, > + void *data) > +{ > + int i, j; > + char *to_remove = xcalloc(array->nr, sizeof(char)); > + > + /* No oid_array_sort() here! See the api-oid-array.txt docs! */ > + > + for (i = 0; i < array->nr; i++) { > + int ret = fn(array->oid + i, data); > + if (ret) > + to_remove[i] = 1; > + } Doing the same without this secondary array and loop, i.e. for (src = dst = 0; src < array->nr; src++) { if (!fn(&array->oid[src], cbdata)) { if (dst < src) oidcpy(&array->oid[dst], &array->oid[src]); dst++; } } array->nr = dst; would be no less efficient. The only reason why you might want to measure move-span by a secondary array and preliminary counting loop like your version does is that moving contiguous area of memory may be more efficient than moving only by a single oid sized chunks, but as far as I can tell you are not doing that "optimization", either. I doubt that remove_if() is particularly a good name. A version of this function, for which polarity of fn() is reversed, can be called "grep", or "filter", I think, and would be more understandable.