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{ "id": 23118, "url": "https://patchwork.libcamera.org/api/patches/23118/?format=api", "web_url": "https://patchwork.libcamera.org/patch/23118/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/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": "<20250403154925.382973-3-stefan.klug@ideasonboard.com>", "date": "2025-04-03T15:49:07", "name": "[v3,02/16] libcamera: matrix: Make most functions constexpr", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "cf5110c9ca99479c544fa1c61f85cf62efe6654c", "submitter": { "id": 184, "url": "https://patchwork.libcamera.org/api/people/184/?format=api", "name": "Stefan Klug", "email": "stefan.klug@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/23118/mbox/", "series": [ { "id": 5111, "url": "https://patchwork.libcamera.org/api/series/5111/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5111", "date": "2025-04-03T15:49:05", "name": "Some rkisp1 awb improvements", "version": 3, "mbox": "https://patchwork.libcamera.org/series/5111/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/23118/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/23118/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 E0CB0C327D\n\tfor <parsemail@patchwork.libcamera.org>;\n\tThu, 3 Apr 2025 15:49:42 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 97C9B689A8;\n\tThu, 3 Apr 2025 17:49:42 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id EB826689A4\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tThu, 3 Apr 2025 17:49:40 +0200 (CEST)", "from ideasonboard.com (unknown\n\t[IPv6:2a00:6020:448c:6c00:6d9d:9854:3fc1:4bb2])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 458AB8FA;\n\tThu, 3 Apr 2025 17:47:47 +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=\"UjaJQHE2\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1743695267;\n\tbh=/lShqxVKPC83P8c7ZF16LUmZo5jxREkUBIJoqFx7/k0=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=UjaJQHE2eskJNvLGNEU0NJZCJdv+SG4T6z9XdcV6/hEIkE+/MHGnPfAJaB9hM696u\n\tNF+sQmGnD7ZTlb4zt3tJZO5v1qvqzCu8jLwE+lyfEGOmnYFzj9slydyMEi+1H8KQN3\n\tCq9gOEtQhGsKSZGEO63tJf+zPgY38KneMV2N7RfA=", "From": "Stefan Klug <stefan.klug@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>,\n\tLaurent Pinchart <laurent.pinchart@ideasonboard.com>", "Subject": "[PATCH v3 02/16] libcamera: matrix: Make most functions constexpr", "Date": "Thu, 3 Apr 2025 17:49:07 +0200", "Message-ID": "<20250403154925.382973-3-stefan.klug@ideasonboard.com>", "X-Mailer": "git-send-email 2.43.0", "In-Reply-To": "<20250403154925.382973-1-stefan.klug@ideasonboard.com>", "References": "<20250403154925.382973-1-stefan.klug@ideasonboard.com>", "MIME-Version": "1.0", "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": "By zero-initializing the data_ member we can make most functions\nconstexpr which will come in handy in upcoming patches. Note that this\nis due to C++17. In C++20 we will be able to leave data_ uninitialized\nfor constexpr. The Matrix(std::array) version of the constructor can\nnot be constexpr because std::copy only became constexpr in C++20.\n\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\nReviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>\n\n---\n\nChanges in v2:\n- Added this patch\n\nChanges in v3:\n- Added comment on data_ initializer\n---\n include/libcamera/internal/matrix.h | 20 ++++++++++++--------\n 1 file changed, 12 insertions(+), 8 deletions(-)", "diff": "diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\nindex b9c3d41ef855..512c1162c3bc 100644\n--- a/include/libcamera/internal/matrix.h\n+++ b/include/libcamera/internal/matrix.h\n@@ -25,9 +25,8 @@ class Matrix\n \tstatic_assert(std::is_arithmetic_v<T>, \"Matrix type must be arithmetic\");\n \n public:\n-\tMatrix()\n+\tconstexpr Matrix()\n \t{\n-\t\tdata_.fill(static_cast<T>(0));\n \t}\n \n \tMatrix(const std::array<T, Rows * Cols> &data)\n@@ -35,7 +34,7 @@ public:\n \t\tstd::copy(data.begin(), data.end(), data_.begin());\n \t}\n \n-\tstatic Matrix identity()\n+\tstatic constexpr Matrix identity()\n \t{\n \t\tMatrix ret;\n \t\tfor (size_t i = 0; i < std::min(Rows, Cols); i++)\n@@ -63,14 +62,14 @@ public:\n \t\treturn out.str();\n \t}\n \n-\tSpan<const T, Rows * Cols> data() const { return data_; }\n+\tconstexpr Span<const T, Rows * Cols> data() const { return data_; }\n \n-\tSpan<const T, Cols> operator[](size_t i) const\n+\tconstexpr Span<const T, Cols> operator[](size_t i) const\n \t{\n \t\treturn Span<const T, Cols>{ &data_.data()[i * Cols], Cols };\n \t}\n \n-\tSpan<T, Cols> operator[](size_t i)\n+\tconstexpr Span<T, Cols> operator[](size_t i)\n \t{\n \t\treturn Span<T, Cols>{ &data_.data()[i * Cols], Cols };\n \t}\n@@ -88,7 +87,12 @@ public:\n \t}\n \n private:\n-\tstd::array<T, Rows * Cols> data_;\n+\t/*\n+\t * \\todo The initializer is only necessary for the constructor to be\n+\t * constexpr in C++17. Remove the initializer as soon as we are on\n+\t * C++20.\n+\t */\n+\tstd::array<T, Rows * Cols> data_ = {};\n };\n \n #ifndef __DOXYGEN__\n@@ -141,7 +145,7 @@ constexpr Matrix<T, R1, C2> operator*(const Matrix<T, R1, C1> &m1, const Matrix<\n }\n \n template<typename T, unsigned int Rows, unsigned int Cols>\n-Matrix<T, Rows, Cols> operator+(const Matrix<T, Rows, Cols> &m1, const Matrix<T, Rows, Cols> &m2)\n+constexpr Matrix<T, Rows, Cols> operator+(const Matrix<T, Rows, Cols> &m1, const Matrix<T, Rows, Cols> &m2)\n {\n \tMatrix<T, Rows, Cols> result;\n \n", "prefixes": [ "v3", "02/16" ] }