{"id":23874,"url":"https://patchwork.libcamera.org/api/1.1/patches/23874/?format=json","web_url":"https://patchwork.libcamera.org/patch/23874/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20250721104622.1550908-7-barnabas.pocze@ideasonboard.com>","date":"2025-07-21T10:46:06","name":"[RFC,v2,06/22] libcamera: base: Add alignment utility functions","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"84b6096c209abb016dd779b2196921444af73d65","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/1.1/people/216/?format=json","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/23874/mbox/","series":[{"id":5305,"url":"https://patchwork.libcamera.org/api/1.1/series/5305/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5305","date":"2025-07-21T10:46:00","name":"libcamera: Add `MetadataList`","version":2,"mbox":"https://patchwork.libcamera.org/series/5305/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/23874/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/23874/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id E2143C3237\n\tfor ;\n\tMon, 21 Jul 2025 10:46:41 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 4042A68FFD;\n\tMon, 21 Jul 2025 12:46:41 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 20E0D68FE2\n\tfor ;\n\tMon, 21 Jul 2025 12:46:29 +0200 (CEST)","from pb-laptop.local (185.221.140.39.nat.pool.zt.hu\n\t[185.221.140.39])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 3D525795A\n\tfor ;\n\tMon, 21 Jul 2025 12:45:52 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"HJpGUwDk\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1753094752;\n\tbh=5wZ2mESo83czM6kiibaVjGsd5F/u8NtsHKZS1sNOiYM=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=HJpGUwDkp1hQCHyFG8Z7epBFM81Z/V94p69iu6ACvz0Y5AMjJzSEuNNxAdn1CAw3r\n\twwi6zR+ATIjUyzbTSdY/vhuIlbfwqWQDgegkGUKmDfvofOaVRRRD9POqtfCac4Ru+z\n\tGtiZ2zF8IpuT9jqw/8qaFcKJsUqRc4P/m7bLMPqU=","From":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","To":"libcamera-devel@lists.libcamera.org","Subject":"[RFC PATCH v2 06/22] libcamera: base: Add alignment utility\n\tfunctions","Date":"Mon, 21 Jul 2025 12:46:06 +0200","Message-ID":"<20250721104622.1550908-7-barnabas.pocze@ideasonboard.com>","X-Mailer":"git-send-email 2.50.1","In-Reply-To":"<20250721104622.1550908-1-barnabas.pocze@ideasonboard.com>","References":"<20250721104622.1550908-1-barnabas.pocze@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Add a couple internal functions to check alignment, and to\nalign integers, pointer up to a given alignment.\n\nSigned-off-by: Barnabás Pőcze \n---\n include/libcamera/base/details/align.h | 78 ++++++++++++++++++++++++++\n include/libcamera/base/meson.build | 1 +\n 2 files changed, 79 insertions(+)\n create mode 100644 include/libcamera/base/details/align.h","diff":"diff --git a/include/libcamera/base/details/align.h b/include/libcamera/base/details/align.h\nnew file mode 100644\nindex 000000000..e9569613b\n--- /dev/null\n+++ b/include/libcamera/base/details/align.h\n@@ -0,0 +1,78 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2025, Ideas on Board Oy\n+ *\n+ * Alignment utilities\n+ */\n+\n+#pragma once\n+\n+#include \n+#include \n+#include \n+\n+#include \n+\n+namespace libcamera::details::align {\n+\n+inline bool is(const void *p, std::uintptr_t alignment)\n+{\n+\tassert(alignment > 0);\n+\n+\treturn reinterpret_cast(p) % alignment == 0;\n+}\n+\n+template\n+constexpr T up(T x, cxx20::type_identity_t alignment)\n+{\n+\tstatic_assert(std::is_unsigned_v);\n+\tassert(alignment > 0);\n+\n+\tconst auto padding = (alignment - (x % alignment)) % alignment;\n+\tassert(x + padding >= x);\n+\n+\treturn x + padding;\n+}\n+\n+template\n+auto *up(T *p, std::uintptr_t alignment)\n+{\n+\tusing U = std::conditional_t<\n+\t\tstd::is_const_v,\n+\t\tconst std::byte,\n+\t\tstd::byte\n+\t>;\n+\n+\treturn reinterpret_cast(up(reinterpret_cast(p), alignment));\n+}\n+\n+template\n+T *up(std::size_t size, std::size_t alignment, T *&ptr, std::size_t *avail = nullptr)\n+{\n+\tassert(alignment > 0);\n+\n+\tauto p = reinterpret_cast(ptr);\n+\tconst auto padding = (alignment - (p % alignment)) % alignment;\n+\n+\tif (avail) {\n+\t\tif (size > *avail || padding > *avail - size)\n+\t\t\treturn nullptr;\n+\n+\t\t*avail -= size + padding;\n+\t}\n+\n+\tp += padding;\n+\tptr = reinterpret_cast(p + size);\n+\n+\treturn reinterpret_cast(p);\n+}\n+\n+template\n+U *up(T *&ptr, std::size_t *avail = nullptr)\n+{\n+\treturn reinterpret_cast, const U, U> *>(\n+\t\tup(sizeof(U), alignof(U), ptr, avail)\n+\t);\n+}\n+\n+} /* namespace libcamera::details::align */\ndiff --git a/include/libcamera/base/meson.build b/include/libcamera/base/meson.build\nindex 9836daff9..1554b996b 100644\n--- a/include/libcamera/base/meson.build\n+++ b/include/libcamera/base/meson.build\n@@ -33,6 +33,7 @@ libcamera_base_private_headers = files([\n \n libcamera_base_details_headers = files([\n 'details/cxx20.h',\n+ 'details/align.h',\n ])\n \n libcamera_base_headers = [\n","prefixes":["RFC","v2","06/22"]}