From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 08 Jan 2024 08:13:09 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rMjor-008V25-0X for lore@lore.pengutronix.de; Mon, 08 Jan 2024 08:13:09 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rMjoq-0003ke-HB for lore@pengutronix.de; Mon, 08 Jan 2024 08:13:09 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:From:In-Reply-To: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TixmlABiH7PD6z5Z14Skk0OlsefcEGhiIB3dlesQ/HM=; b=RoZ7ZRBzSuV+ALsnDw8x6ih/S4 Bh6a9MltsP1Gx6vaPfbtag6dkuffHGMuJHQX+CWqLJ+74+ziNnPRCht0de1t2EphRkg+COW0iBtS8 8bXvWM25t/UwUs+0N4rPcIKadgiKY3uJ048ZNJIC1LmO+Ob6Vy+JTvnNc6UrmZm+4AxKwrHJTFBV5 g/IzWQkwMJVbFljd2ryC+fwW7aoYEWP91EE2B2I9nX/Puwnx4XskV7ol2sr4TNOM0S6hapzY/FM7W FiUhjG0bnhgj7g06Hpfm6hM3Be8iKl1kllASRUrP70/0Ar2WNpJr6127PlXpPKt8GrR9IgUF5irnB ztpe120A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rMjn0-0049Or-2O; Mon, 08 Jan 2024 07:11:14 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rMjmw-0049OD-2T for barebox@lists.infradead.org; Mon, 08 Jan 2024 07:11:12 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rMjmr-0003Zq-Kl; Mon, 08 Jan 2024 08:11:05 +0100 Received: from [2a0a:edc0:2:b01:1d::c0] (helo=ptx.whiteo.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rMjmr-001C4H-7S; Mon, 08 Jan 2024 08:11:05 +0100 Received: from sha by ptx.whiteo.stw.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1rMjmr-00AnrD-4u; Mon, 08 Jan 2024 08:11:05 +0100 Date: Mon, 8 Jan 2024 08:11:05 +0100 To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: <20240108071105.GX1318922@pengutronix.de> References: <20240103181312.409668-1-a.fatoum@pengutronix.de> <20240103181312.409668-48-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240103181312.409668-48-a.fatoum@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) From: Sascha Hauer X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240107_231110_821665_CCDB30EF X-CRM114-Status: GOOD ( 27.01 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-6.1 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 047/112] string: reduce strjoin runtime, drop trailing separator X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On Wed, Jan 03, 2024 at 07:12:07PM +0100, Ahmad Fatoum wrote: > The implementation of strjoin is a bit suboptimal. The destination > string is traversed from the beginning due to strcat and we have a > left-over separator at the end, while it should only be in-between. > > Fix this. > > Signed-off-by: Ahmad Fatoum > --- > Originally posted at: https://lore.barebox.org/barebox/20221027073334.GS6702@pengutronix.de/ Once again I ended up reviewing a suboptimal version of strjoin() first just to find my potential comments addressed in the next patch. So my comment to the last version still stands: Please implement a good version of strjoin() first and then switch over to use it. > > Changes: > - remove if statemnt in loop (Sascha) > Signed-off-by: Ahmad Fatoum > --- > lib/string.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/lib/string.c b/lib/string.c > index d8e5edd40648..695e50bc8fc1 100644 > --- a/lib/string.c > +++ b/lib/string.c > @@ -1005,7 +1005,7 @@ char *strjoin(const char *separator, char **arr, size_t arrlen) > { > size_t separatorlen; > int len = 1; /* '\0' */ > - char *buf; > + char *buf, *p; > int i; > > separatorlen = strlen(separator); > @@ -1013,13 +1013,18 @@ char *strjoin(const char *separator, char **arr, size_t arrlen) > for (i = 0; i < arrlen; i++) > len += strlen(arr[i]) + separatorlen; Not that it matters much for memory usage, but for consistency you could drop the final separatorlen just like you did for copying the strings below. Sascha > > - buf = xzalloc(len); > + if (!arrlen) > + return xzalloc(1); > > - for (i = 0; i < arrlen; i++) { > - strcat(buf, arr[i]); > - strcat(buf, separator); > + p = buf = xmalloc(len); > + > + for (i = 0; i < arrlen - 1; i++) { > + p = stpcpy(p, arr[i]); > + p = mempcpy(p, separator, separatorlen); > } > > + stpcpy(p, arr[i]); > + > return buf; > } > EXPORT_SYMBOL(strjoin); > -- > 2.39.2 > > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |