From patchwork Fri Jun 6 16:41:39 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: 23487 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 343EEC3326 for ; Fri, 6 Jun 2025 16:42:37 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id EAC2B68DB0; Fri, 6 Jun 2025 18:42:34 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="cd6uaOdL"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 95F6968DC1 for ; Fri, 6 Jun 2025 18:42:16 +0200 (CEST) Received: from pb-laptop.local (185.182.215.79.nat.pool.zt.hu [185.182.215.79]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 265238DB for ; Fri, 6 Jun 2025 18:42:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1749228132; bh=iIDSatRfy0cQy+iqy8owgNdQ6BhWbHCC8Hz44BO/7ws=; h=From:To:Subject:Date:In-Reply-To:References:From; b=cd6uaOdLn6JPFVaUnFs6GULk87r//6kq7Ft53pG5VqgDyd+D7nnt5LqPfxt9mDScS QQBKgX13GRHupeioGlD/FCcbs369jTNAKVT/DZzCWx97aiflR8AhAtJxB1XKlqplc6 GYafglcV1LlcAv0XcnCz25oDbmPRR2/gWi6+ruiI= From: =?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= To: libcamera-devel@lists.libcamera.org Subject: [RFC PATCH v1 06/23] libcamera: base: Add alignment utility functions Date: Fri, 6 Jun 2025 18:41:39 +0200 Message-ID: <20250606164156.1442682-7-barnabas.pocze@ideasonboard.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250606164156.1442682-1-barnabas.pocze@ideasonboard.com> References: <20250606164156.1442682-1-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 | 72 ++++++++++++++++++++++++++ 1 file changed, 72 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..e1c24c6e1 --- /dev/null +++ b/include/libcamera/base/details/align.h @@ -0,0 +1,72 @@ +#pragma once + +#include +#include +#include + +#include + +namespace libcamera::details::align { + +template +bool is(T *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 */