{"id":23117,"url":"https://patchwork.libcamera.org/api/patches/23117/?format=json","web_url":"https://patchwork.libcamera.org/patch/23117/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/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":"<20250403154925.382973-2-stefan.klug@ideasonboard.com>","date":"2025-04-03T15:49:06","name":"[v3,01/16] libcamera: matrix: Replace SFINAE with static_asserts","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"ddee202ece58752c0a05644d8d6254ef11ac3dce","submitter":{"id":184,"url":"https://patchwork.libcamera.org/api/people/184/?format=json","name":"Stefan Klug","email":"stefan.klug@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/23117/mbox/","series":[{"id":5111,"url":"https://patchwork.libcamera.org/api/series/5111/?format=json","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/23117/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/23117/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 4AE4FC327D\n\tfor ;\n\tThu, 3 Apr 2025 15:49:41 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 01136689A1;\n\tThu, 3 Apr 2025 17:49:40 +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 0310C68994\n\tfor ;\n\tThu, 3 Apr 2025 17:49:38 +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 4C71D8FA;\n\tThu, 3 Apr 2025 17:47:44 +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=\"XnT7DVGe\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1743695264;\n\tbh=wqVFTWlEEvkd8wBvHVZ2TIAwLhLy8s/Y2fDw4vYnFcA=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=XnT7DVGe4fTQ/rhS9ZTBYLk8Oyqa4V8YnDqI6u7iXX1pnB4qIkLz87/JQzrTp+nOJ\n\tRUtpJzFRXQinxPSnspnFcOXLmnPVQpUpsX40WxsprMYKTRXE7bw61souPQAF8g3+99\n\tnRZoqJqgKJsOwCiiwQmP0Qv89NziZd+0SJClMMPQ=","From":"Stefan Klug ","To":"libcamera-devel@lists.libcamera.org","Cc":"Stefan Klug ,\n\tLaurent Pinchart ","Subject":"[PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","Date":"Thu, 3 Apr 2025 17:49:06 +0200","Message-ID":"<20250403154925.382973-2-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":"","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":"SFINAE is difficult to read and not needed in these cases. Replace it\nwith static_asserts. The idea came from [1] where it is stated:\n\n\"The use of enable_if seems misguided to me. SFINAE is useful for the\nsituation where we consider multiple candidates for something (overloads\nor class template specializations) and try to choose the correct one,\nwithout causing compilation to fail.\"\n\n[1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n\nSigned-off-by: Stefan Klug \nReviewed-by: Laurent Pinchart \n\n---\n\nChanges in v2:\n- Added this patch\n\nChanges in v3:\n- Left SFINAE in place for the operators as static asserts could cause\n issues there\n---\n include/libcamera/internal/matrix.h | 19 +++++--------------\n 1 file changed, 5 insertions(+), 14 deletions(-)","diff":"diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\nindex a055e6926c94..b9c3d41ef855 100644\n--- a/include/libcamera/internal/matrix.h\n+++ b/include/libcamera/internal/matrix.h\n@@ -19,14 +19,11 @@ namespace libcamera {\n \n LOG_DECLARE_CATEGORY(Matrix)\n \n-#ifndef __DOXYGEN__\n-template> * = nullptr>\n-#else\n template\n-#endif /* __DOXYGEN__ */\n class Matrix\n {\n+\tstatic_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n+\n public:\n \tMatrix()\n \t{\n@@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n \treturn d * m;\n }\n \n-#ifndef __DOXYGEN__\n-template * = nullptr>\n-#else\n-template\n-#endif /* __DOXYGEN__ */\n-Matrix operator*(const Matrix &m1, const Matrix &m2)\n+template\n+constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n {\n+\tstatic_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n \tMatrix result;\n \n \tfor (unsigned int i = 0; i < R1; i++) {\n","prefixes":["v3","01/16"]}