From patchwork Mon Jul 21 10:46:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= X-Patchwork-Id: 23874 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id E2143C3237 for ; Mon, 21 Jul 2025 10:46:41 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 4042A68FFD; Mon, 21 Jul 2025 12:46:41 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="HJpGUwDk"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 20E0D68FE2 for ; Mon, 21 Jul 2025 12:46:29 +0200 (CEST) Received: from pb-laptop.local (185.221.140.39.nat.pool.zt.hu [185.221.140.39]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 3D525795A for ; Mon, 21 Jul 2025 12:45:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1753094752; bh=5wZ2mESo83czM6kiibaVjGsd5F/u8NtsHKZS1sNOiYM=; h=From:To:Subject:Date:In-Reply-To:References:From; b=HJpGUwDkp1hQCHyFG8Z7epBFM81Z/V94p69iu6ACvz0Y5AMjJzSEuNNxAdn1CAw3r wwi6zR+ATIjUyzbTSdY/vhuIlbfwqWQDgegkGUKmDfvofOaVRRRD9POqtfCac4Ru+z GtiZ2zF8IpuT9jqw/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 functions 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 X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Add a couple internal functions to check alignment, and to align integers, pointer up to a given alignment. Signed-off-by: Barnabás Pőcze --- include/libcamera/base/details/align.h | 78 ++++++++++++++++++++++++++ include/libcamera/base/meson.build | 1 + 2 files changed, 79 insertions(+) create mode 100644 include/libcamera/base/details/align.h diff --git a/include/libcamera/base/details/align.h b/include/libcamera/base/details/align.h new file mode 100644 index 000000000..e9569613b --- /dev/null +++ b/include/libcamera/base/details/align.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2025, Ideas on Board Oy + * + * Alignment utilities + */ + +#pragma once + +#include +#include +#include + +#include + +namespace libcamera::details::align { + +inline bool is(const void *p, std::uintptr_t alignment) +{ + assert(alignment > 0); + + return reinterpret_cast(p) % alignment == 0; +} + +template +constexpr T up(T x, cxx20::type_identity_t alignment) +{ + static_assert(std::is_unsigned_v); + assert(alignment > 0); + + const auto padding = (alignment - (x % alignment)) % alignment; + assert(x + padding >= x); + + return x + padding; +} + +template +auto *up(T *p, std::uintptr_t alignment) +{ + using U = std::conditional_t< + std::is_const_v, + const std::byte, + std::byte + >; + + return reinterpret_cast(up(reinterpret_cast(p), alignment)); +} + +template +T *up(std::size_t size, std::size_t alignment, T *&ptr, std::size_t *avail = nullptr) +{ + assert(alignment > 0); + + auto p = reinterpret_cast(ptr); + const auto padding = (alignment - (p % alignment)) % alignment; + + if (avail) { + if (size > *avail || padding > *avail - size) + return nullptr; + + *avail -= size + padding; + } + + p += padding; + ptr = reinterpret_cast(p + size); + + return reinterpret_cast(p); +} + +template +U *up(T *&ptr, std::size_t *avail = nullptr) +{ + return reinterpret_cast, const U, U> *>( + up(sizeof(U), alignof(U), ptr, avail) + ); +} + +} /* namespace libcamera::details::align */ diff --git a/include/libcamera/base/meson.build b/include/libcamera/base/meson.build index 9836daff9..1554b996b 100644 --- a/include/libcamera/base/meson.build +++ b/include/libcamera/base/meson.build @@ -33,6 +33,7 @@ libcamera_base_private_headers = files([ libcamera_base_details_headers = files([ 'details/cxx20.h', + 'details/align.h', ]) libcamera_base_headers = [