From patchwork Tue Feb 18 13:00:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Hindborg X-Patchwork-Id: 13979784 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D98B267F4C; Tue, 18 Feb 2025 13:01:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739883707; cv=none; b=TMAfGVPkWwzPCSTR1Uej9p6qkf+NNdp1CChPLarfzADxTB/IRMejazgAPrwxr5/NQ+lJtacdm/RjUiK3LN/9tbpMEz0pgPxL/GWSUmZKpVgclZ+9LzUuXW+ZqmsixIldmTQ5zZLjTcI8jOTUqOpiitp3ebWNBrInHsXQ+x0i2Zk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739883707; c=relaxed/simple; bh=i8wDoobO6bpiZd26u4+7TLx2QrCQIwRboF1OHEy8KdY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=O22Iq07kt3h1nhZTIshr8cnw6uqwR3IUCABIdKnRs5oCp+58KIEyYMg5lx45x7EOBlynxn6WXfaViNHwbUpdEqSJX5euVFtJmYqVEmhD81W7OYZMTU2vdh92VCKDJ8MPiS3+yNWraQZOioifGB2JU1JsdzKwE7jqrkdwe3I68w8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XFX7qWlO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XFX7qWlO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 292E2C4CEE8; Tue, 18 Feb 2025 13:01:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739883707; bh=i8wDoobO6bpiZd26u4+7TLx2QrCQIwRboF1OHEy8KdY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=XFX7qWlO9SUhgdW7HQvoaB6iK2So0vYTIgDQgJigmZ4atQd8fb6YUkM/O+VYkCoxT 99imA0eFR3aLJ7MSKEwlGENFBHo5yCTm+AI3I4YJwG366dG2VE+qmQm5ojMZORU+gC Tbu3ntTK+vJMC2G68mAhr2osdQ7jvs0XaCv/xy0GSsImf3K7W0tmFGsEFRs4F3CHwe 0P2+Dzry/7Te69G/W82cuLeGVyuSVQYsfS1/a6WqytcUh04CCzKRhW1extSTgbtSKQ M54+LxM+DV0qhIwvI00jieyFNKh4c6OArERHykjfcIh5ae4wr87DFYqJ0JEhoS2CZ6 4XaDLDVnVdp3w== From: Andreas Hindborg Date: Tue, 18 Feb 2025 14:00:46 +0100 Subject: [PATCH v7 4/6] rust: str: implement `strip_prefix` for `BStr` Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250218-module-params-v3-v7-4-5e1afabcac1b@kernel.org> References: <20250218-module-params-v3-v7-0-5e1afabcac1b@kernel.org> In-Reply-To: <20250218-module-params-v3-v7-0-5e1afabcac1b@kernel.org> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Masahiro Yamada , Nathan Chancellor , Nicolas Schier , Luis Chamberlain Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Adam Bratschi-Kaye , linux-kbuild@vger.kernel.org, Petr Pavlu , Sami Tolvanen , Daniel Gomez , Simona Vetter , Greg KH , linux-modules@vger.kernel.org X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1603; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=i8wDoobO6bpiZd26u4+7TLx2QrCQIwRboF1OHEy8KdY=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBntISGYFVJJPsX7afbpIBc/fwF692CI7LF5379D BeVodH8mNWJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCZ7SEhgAKCRDhuBo+eShj dwpjD/wO5E4AFgGZvg4pqp74C2eRjkj1DWNc72uyZ+T2yS5yAgyl9ZOchb1IACBZLwg7dtQvmCc gfH4v39sOzJzGGEY5Tfq2U9T5Jhziobh/tmqZw9x3rJcaG6GK/HSx4pHnGCvN7km58JxjFUDHBg XUNzh8AkiNejZlZv+HfcHunUClrF1b9CGxJfJbo/LhctHNf+fjO5eFOuEB9nvQV4gqO+rt9OrxO btfk0PP2yRZY1mgAAOt0DathpcbA2VKtImhEYxqjKo4R7coK+Q6tW6DHhxHX4naInpmopCylCey tVxd86SYh4OEQwXF2TV1bC3cQsm9wy273n/gwoSCMr/OiimCJcwXBiEUvLDeLvG/PbEZ8Xbm/mc UdwKb/gvQmaP1atypWFjq7I95uNXKVPt0xfUHCXOp5bhnWnn8n1UteJRYvG8eNSE2KFBHhR+kLE OW0aomSHQ8zDON8DsGYVWF3DjxLDq3DOvcN84qYWYzcrEwfpjdMwfQ5zzHw8Vqwt0ZW41zorraZ c7ZlYZpDwRoPezfDIMBCwJsv5QxMMQlDQ1dkgth5yVaVSpiraBrU2+gMrQLaCjjVre9uQ1csmJb DC5lWWs9EmF4eu9itqmEOEKr5DEgRsqsQ7vLiA/zEKUCPZyTLGShCUbPaubgs3aOOUnXE+ZPac5 N3RPiD1pNP1nhpA== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Implement `strip_prefix` for `BStr` by deferring to `slice::strip_prefix` on the underlying `&[u8]`. Reviewed-by: Gary Guo Reviewed-by: Alice Ryhl Signed-off-by: Andreas Hindborg Reviewed-by: Daniel Almeida --- It is also possible to get this method by implementing `core::slice::SlicePattern` for `BStr`. `SlicePattern` is unstable, so this seems more reasonable. --- rust/kernel/str.rs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index c6bd2c69543dc..db272d2198fcc 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -31,6 +31,22 @@ pub const fn from_bytes(bytes: &[u8]) -> &Self { // SAFETY: `BStr` is transparent to `[u8]`. unsafe { &*(bytes as *const [u8] as *const BStr) } } + + /// Strip a prefix from `self`. Delegates to [`slice::strip_prefix`]. + /// + /// # Example + /// ``` + /// use kernel::b_str; + /// assert_eq!(Some(b_str!("bar")), b_str!("foobar").strip_prefix(b_str!("foo"))); + /// assert_eq!(None, b_str!("foobar").strip_prefix(b_str!("bar"))); + /// assert_eq!(Some(b_str!("foobar")), b_str!("foobar").strip_prefix(b_str!(""))); + /// assert_eq!(Some(b_str!("")), b_str!("foobar").strip_prefix(b_str!("foobar"))); + /// ``` + pub fn strip_prefix(&self, pattern: impl AsRef) -> Option<&BStr> { + self.deref() + .strip_prefix(pattern.as_ref().deref()) + .map(Self::from_bytes) + } } impl fmt::Display for BStr {