From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 08 Aug 2022 13:21:38 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1oL0pE-00G5lt-71 for lore@lore.pengutronix.de; Mon, 08 Aug 2022 13:21:38 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oL0pF-00017L-4c for lore@pengutronix.de; Mon, 08 Aug 2022 13:21:37 +0200 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=wlEN7Cc0z++EP9Ye2kArtTz0voCyqutg1tkNyV0q7b0=; b=ytfI1VzBfqo0a8jKeDWQxnjcEs vGnQU4N8WaYMA4BR41QbuoZ49hpDw5E3HIXVs9AI03jsZ5h+h85S1dZ3mu2MNjHSo8bfdmwNFMROf HvPzlFkfo3mfWHUiKMEqCth6d17HZneQ04S5pBM9+YodrcVs19HW2UPLhNzRBhunmALVXabgJddDt Wcy5aLGf0xgLxxd+0EF77OVxDniaR04Ea46rGRy4H/I0kR/uUB8tdbCccrLt+H1dDAY2V9Xo62xaT JYoQcuEIAAi7k1QHTqM/NKNKECiUjQLuqDh9DQz3mmWn7Yd/rd4xtNMyYnsFn476PumN5q2RN/RC2 zaaORQBA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oL0o4-00DBXC-M1; Mon, 08 Aug 2022 11:20:24 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oL0o0-00DBWC-PF for barebox@lists.infradead.org; Mon, 08 Aug 2022 11:20:22 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oL0nz-0000nI-HL; Mon, 08 Aug 2022 13:20:19 +0200 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1oL0nz-0005Pj-8H; Mon, 08 Aug 2022 13:20:19 +0200 Date: Mon, 8 Aug 2022 13:20:19 +0200 To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: <20220808112019.GF7333@pengutronix.de> References: <20220808062028.391120-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220808062028.391120-1-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-20220808_042020_835532_266E2FF5 X-CRM114-Status: GOOD ( 24.23 ) 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.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.1 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH] string: implement str_has_prefix X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) On Mon, Aug 08, 2022 at 08:20:28AM +0200, Ahmad Fatoum wrote: > In addition to strstarts which we already have, Linux also defines > str_has_prefix(), which returns the length of the prefix on success and > zero otherwise. This allows writing straight-forward code to skip over > a prefix in case it exists. Port it over. > > Signed-off-by: Ahmad Fatoum > --- > include/linux/string.h | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) Applied, thanks Sascha > > diff --git a/include/linux/string.h b/include/linux/string.h > index ae5e5bca8d24..0c79d3e5cf3e 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -155,4 +155,25 @@ static inline bool strstarts(const char *str, const char *prefix) > return strncmp(str, prefix, strlen(prefix)) == 0; > } > > +/** > + * str_has_prefix - Test if a string has a given prefix > + * @str: The string to test > + * @prefix: The string to see if @str starts with > + * > + * A common way to test a prefix of a string is to do: > + * strncmp(str, prefix, sizeof(prefix) - 1) > + * > + * But this can lead to bugs due to typos, or if prefix is a pointer > + * and not a constant. Instead use str_has_prefix(). > + * > + * Returns: > + * * strlen(@prefix) if @str starts with @prefix > + * * 0 if @str does not start with @prefix > + */ > +static __always_inline size_t str_has_prefix(const char *str, const char *prefix) > +{ > + size_t len = strlen(prefix); > + return strncmp(str, prefix, len) == 0 ? len : 0; > +} > + > #endif /* _LINUX_STRING_H_ */ > -- > 2.30.2 > > > -- 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 |