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{ "id": 23874, "url": "https://patchwork.libcamera.org/api/1.1/patches/23874/?format=api", "web_url": "https://patchwork.libcamera.org/patch/23874/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "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"[RFC,v2,06/22] libcamera: base: Add alignment utility functions", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": false, "hash": "84b6096c209abb016dd779b2196921444af73d65", "submitter": { "id": 216, "url":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=api", "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=api", "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": "<libcamera-devel-bounces@lists.libcamera.org>", "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 <parsemail@patchwork.libcamera.org>;\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 <libcamera-devel@lists.libcamera.org>;\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 <libcamera-devel@lists.libcamera.org>;\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?= <barnabas.pocze@ideasonboard.com>", "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": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "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 <barnabas.pocze@ideasonboard.com>\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 <cassert>\n+#include <cstddef>\n+#include <cstdint>\n+\n+#include <libcamera/base/details/cxx20.h>\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<std::uintptr_t>(p) % alignment == 0;\n+}\n+\n+template<typename T>\n+constexpr T up(T x, cxx20::type_identity_t<T> alignment)\n+{\n+\tstatic_assert(std::is_unsigned_v<T>);\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<typename T>\n+auto *up(T *p, std::uintptr_t alignment)\n+{\n+\tusing U = std::conditional_t<\n+\t\tstd::is_const_v<T>,\n+\t\tconst std::byte,\n+\t\tstd::byte\n+\t>;\n+\n+\treturn reinterpret_cast<U *>(up(reinterpret_cast<std::uintptr_t>(p), alignment));\n+}\n+\n+template<typename T>\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<std::uintptr_t>(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<T *>(p + size);\n+\n+\treturn reinterpret_cast<T *>(p);\n+}\n+\n+template<typename U, typename T>\n+U *up(T *&ptr, std::size_t *avail = nullptr)\n+{\n+\treturn reinterpret_cast<std::conditional_t<std::is_const_v<T>, 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" ] }