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{ "id": 13112, "url": "https://patchwork.libcamera.org/api/1.1/patches/13112/?format=api", "web_url": "https://patchwork.libcamera.org/patch/13112/", "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": "<20210725171827.23643-2-laurent.pinchart@ideasonboard.com>", "date": "2021-07-25T17:18:23", "name": "[libcamera-devel,v2,1/5] libcamera: flags: Add type-safe enum-based flags", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "7c63b58f3973407f14dcf9ee665043a81a7039ae", "submitter": { "id": 2, "url": "https://patchwork.libcamera.org/api/1.1/people/2/?format=api", "name": "Laurent Pinchart", "email": "laurent.pinchart@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/13112/mbox/", "series": [ { "id": 2276, "url": "https://patchwork.libcamera.org/api/1.1/series/2276/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=2276", "date": "2021-07-25T17:18:22", "name": "libcamera: Add type-safe enum-based flags", "version": 2, "mbox": "https://patchwork.libcamera.org/series/2276/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/13112/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/13112/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 8A4D1C322C\n\tfor <parsemail@patchwork.libcamera.org>;\n\tSun, 25 Jul 2021 17:18:41 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 057A5687BF;\n\tSun, 25 Jul 2021 19:18:39 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 3DA366877B\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tSun, 25 Jul 2021 19:18:37 +0200 (CEST)", "from pendragon.lan (62-78-145-57.bb.dnainternet.fi [62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id C58524A8\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tSun, 25 Jul 2021 19:18:36 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"NNpgTHfR\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1627233516;\n\tbh=vLytBX/gZIMllE5STYAdBUWnekiqZDrwcVoIeNj9CF0=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=NNpgTHfRFbDJmO3LR+HA026yBOUzmBJAm5v5IckULaa0dsOpuKA/rGQPY0A1gBx+J\n\tMeHsQpR0ICXPYYMOF/a3yUFSWQMIC4niqm0yB2kx8kg70ux3qNRVbltuq89ctFr/+F\n\t435/6QpfQTgag1UnQFLvS4z4HnPll2uODVfQ8CMo=", "From": "Laurent Pinchart <laurent.pinchart@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Date": "Sun, 25 Jul 2021 20:18:23 +0300", "Message-Id": "<20210725171827.23643-2-laurent.pinchart@ideasonboard.com>", "X-Mailer": "git-send-email 2.31.1", "In-Reply-To": "<20210725171827.23643-1-laurent.pinchart@ideasonboard.com>", "References": "<20210725171827.23643-1-laurent.pinchart@ideasonboard.com>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "Content-Transfer-Encoding": "8bit", "Subject": "[libcamera-devel] [PATCH v2 1/5] libcamera: flags: Add type-safe\n\tenum-based flags", "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 Flags template class that provide type-safe bitwise operators on\nenum values. This allows using enum types for bit fields, without giving\naway type-safety as usually done when storing combined flags in integer\nvariables.\n\nSigned-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>\nReviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>\n---\n include/libcamera/base/flags.h | 195 +++++++++++++++++++++++++++++\n include/libcamera/base/meson.build | 1 +\n src/libcamera/base/flags.cpp | 192 ++++++++++++++++++++++++++++\n src/libcamera/base/meson.build | 1 +\n 4 files changed, 389 insertions(+)\n create mode 100644 include/libcamera/base/flags.h\n create mode 100644 src/libcamera/base/flags.cpp", "diff": "diff --git a/include/libcamera/base/flags.h b/include/libcamera/base/flags.h\nnew file mode 100644\nindex 000000000000..adec549dccc9\n--- /dev/null\n+++ b/include/libcamera/base/flags.h\n@@ -0,0 +1,195 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2020, Google Inc.\n+ *\n+ * flags.h - Type-safe enum-based bitfields\n+ */\n+#ifndef __LIBCAMERA_BASE_FLAGS_H__\n+#define __LIBCAMERA_BASE_FLAGS_H__\n+\n+#include <type_traits>\n+\n+namespace libcamera {\n+\n+template<typename E>\n+class Flags\n+{\n+public:\n+\tstatic_assert(std::is_enum<E>::value,\n+\t\t \"Flags<> template parameter must be an enum\");\n+\n+\tusing Type = std::underlying_type_t<E>;\n+\n+\tconstexpr Flags()\n+\t\t: value_(0)\n+\t{\n+\t}\n+\n+\tconstexpr Flags(E flag)\n+\t\t: value_(static_cast<Type>(flag))\n+\t{\n+\t}\n+\n+\tconstexpr Flags &operator&=(E flag)\n+\t{\n+\t\tvalue_ &= static_cast<Type>(flag);\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr Flags &operator&=(Flags other)\n+\t{\n+\t\tvalue_ &= other.value_;\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr Flags &operator|=(E flag)\n+\t{\n+\t\tvalue_ |= static_cast<Type>(flag);\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr Flags &operator|=(Flags other)\n+\t{\n+\t\tvalue_ |= other.value_;\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr Flags &operator^=(E flag)\n+\t{\n+\t\tvalue_ ^= static_cast<Type>(flag);\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr Flags &operator^=(Flags other)\n+\t{\n+\t\tvalue_ ^= other.value_;\n+\t\treturn *this;\n+\t}\n+\n+\tconstexpr bool operator==(E flag)\n+\t{\n+\t\treturn value_ == static_cast<Type>(flag);\n+\t}\n+\n+\tconstexpr bool operator==(Flags other)\n+\t{\n+\t\treturn value_ == static_cast<Type>(other);\n+\t}\n+\n+\tconstexpr bool operator!=(E flag)\n+\t{\n+\t\treturn value_ != static_cast<Type>(flag);\n+\t}\n+\n+\tconstexpr bool operator!=(Flags other)\n+\t{\n+\t\treturn value_ != static_cast<Type>(other);\n+\t}\n+\n+\tconstexpr explicit operator Type() const\n+\t{\n+\t\treturn value_;\n+\t}\n+\n+\tconstexpr explicit operator bool() const\n+\t{\n+\t\treturn !!value_;\n+\t}\n+\n+\tconstexpr Flags operator&(E flag) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ & static_cast<Type>(flag)));\n+\t}\n+\n+\tconstexpr Flags operator&(Flags other) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ & other.value_));\n+\t}\n+\n+\tconstexpr Flags operator|(E flag) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ | static_cast<Type>(flag)));\n+\t}\n+\n+\tconstexpr Flags operator|(Flags other) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ | other.value_));\n+\t}\n+\n+\tconstexpr Flags operator^(E flag) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ ^ static_cast<Type>(flag)));\n+\t}\n+\n+\tconstexpr Flags operator^(Flags other) const\n+\t{\n+\t\treturn Flags(static_cast<E>(value_ ^ other.value_));\n+\t}\n+\n+\tconstexpr Flags operator~() const\n+\t{\n+\t\treturn Flags(static_cast<E>(~value_));\n+\t}\n+\n+\tconstexpr bool operator!() const\n+\t{\n+\t\treturn !value_;\n+\t}\n+\n+private:\n+\tType value_;\n+};\n+\n+#ifndef __DOXYGEN__\n+template<typename E>\n+struct flags_enable_operators {\n+\tstatic const bool enable = false;\n+};\n+\n+template<typename E>\n+typename std::enable_if_t<flags_enable_operators<E>::enable, Flags<E>>\n+operator|(E lhs, E rhs)\n+{\n+\tusing type = std::underlying_type_t<E>;\n+\treturn Flags<E>(static_cast<E>(static_cast<type>(lhs) | static_cast<type>(rhs)));\n+}\n+\n+template<typename E>\n+typename std::enable_if_t<flags_enable_operators<E>::enable, Flags<E>>\n+operator&(E lhs, E rhs)\n+{\n+\tusing type = std::underlying_type_t<E>;\n+\treturn Flags<E>(static_cast<E>(static_cast<type>(lhs) & static_cast<type>(rhs)));\n+}\n+\n+template<typename E>\n+typename std::enable_if_t<flags_enable_operators<E>::enable, Flags<E>>\n+operator^(E lhs, E rhs)\n+{\n+\tusing type = std::underlying_type_t<E>;\n+\treturn Flags<E>(static_cast<E>(static_cast<type>(lhs) ^ static_cast<type>(rhs)));\n+}\n+\n+template<typename E>\n+typename std::enable_if_t<flags_enable_operators<E>::enable, Flags<E>>\n+operator~(E rhs)\n+{\n+\tusing type = std::underlying_type_t<E>;\n+\treturn Flags<E>(static_cast<E>(~static_cast<type>(rhs)));\n+}\n+\n+#define LIBCAMERA_FLAGS_ENABLE_OPERATORS(_enum)\t\t\t\t\\\n+template<>\t\t\t\t\t\t\t\t\\\n+struct flags_enable_operators<_enum> {\t\t\t\t\t\\\n+\tstatic const bool enable = true;\t\t\t\t\\\n+};\n+\n+#else /* __DOXYGEN__ */\n+\n+#define LIBCAMERA_FLAGS_ENABLE_OPERATORS(_enum)\n+\n+#endif /* __DOXYGEN__ */\n+\n+} /* namespace libcamera */\n+\n+#endif /* __LIBCAMERA_BASE_FLAGS_H__ */\ndiff --git a/include/libcamera/base/meson.build b/include/libcamera/base/meson.build\nindex 7c499b558fb0..9feb4b9346d5 100644\n--- a/include/libcamera/base/meson.build\n+++ b/include/libcamera/base/meson.build\n@@ -9,6 +9,7 @@ libcamera_base_headers = files([\n 'event_dispatcher_poll.h',\n 'event_notifier.h',\n 'file.h',\n+ 'flags.h',\n 'log.h',\n 'message.h',\n 'object.h',\ndiff --git a/src/libcamera/base/flags.cpp b/src/libcamera/base/flags.cpp\nnew file mode 100644\nindex 000000000000..3e4320ace7c8\n--- /dev/null\n+++ b/src/libcamera/base/flags.cpp\n@@ -0,0 +1,192 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2020, Google Inc.\n+ *\n+ * flags.cpp - Type-safe enum-based bitfields\n+ */\n+\n+#include <libcamera/base/flags.h>\n+\n+/**\n+ * \\file base/flags.h\n+ * \\brief Enum-based bit fields\n+ */\n+\n+namespace libcamera {\n+\n+/**\n+ * \\class Flags\n+ * \\brief Type-safe container for enum-based bitfields\n+ *\n+ * The Flags template class provides type-safe bitwise operators on enum values.\n+ * It allows using enum types for bitfields, while preventing unsafe casts from\n+ * integer types and mixing of flags from different enum types.\n+ *\n+ * To use the Flags class, declare an enum containing the desired bit flags, and\n+ * use the Flags<enum> class to store bitfields based on the enum. If bitwise\n+ * operators on the underlying enum are also desired, they can be enabled with\n+ * the LIBCAMERA_FLAGS_ENABLE_OPERATORS(enum) macro.\n+ */\n+\n+/**\n+ * \\typedef Flags::Type\n+ * \\brief The underlying data type of the enum\n+ */\n+\n+/**\n+ * \\fn Flags::Flags()\n+ * \\brief Construct a Flags instance with a zero value\n+ */\n+\n+/**\n+ * \\fn Flags::Flags(E flag)\n+ * \\brief Construct a Flags instance storing the \\a flag\n+ * \\param[in] flag The initial value\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator&=(E flag)\n+ * \\brief Store the bitwise AND of this Flags and the \\a flag in this Flags\n+ * \\param[in] flag The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator&=(Flags other)\n+ * \\brief Store the bitwise AND of this Flags and the \\a other Flags in this Flags\n+ * \\param[in] other The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator|=(E flag)\n+ * \\brief Store the bitwise OR of this Flags and the \\a flag in this Flags\n+ * \\param[in] flag The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator|=(Flags other)\n+ * \\brief Store the bitwise OR of this Flags and the \\a other Flags in this Flags\n+ * \\param[in] other The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator^=(E flag)\n+ * \\brief Store the bitwise XOR of this Flags and the \\a flag in this Flags\n+ * \\param[in] flag The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn Flags &Flags::operator^=(Flags other)\n+ * \\brief Store the bitwise XOR of this Flags and the \\a other Flags in this Flags\n+ * \\param[in] other The second operand\n+ * \\return A reference to this Flags\n+ */\n+\n+/**\n+ * \\fn bool Flags::operator==(E flag)\n+ * \\brief Compare flags for equality\n+ * \\param[in] flag The second operand\n+ * \\return True if the Flags and \\a flag are equal, false otherwise\n+ */\n+\n+/**\n+ * \\fn bool Flags::operator==(Flags other)\n+ * \\brief Compare flags for equality\n+ * \\param[in] other The second operand\n+ * \\return True if the Flags and \\a other are equal, false otherwise\n+ */\n+\n+/**\n+ * \\fn bool Flags::operator!=(E flag)\n+ * \\brief Compare flags for non-equality\n+ * \\param[in] flag The second operand\n+ * \\return True if the Flags and \\a flag are not equal, false otherwise\n+ */\n+\n+/**\n+ * \\fn bool Flags::operator!=(Flags other)\n+ * \\brief Compare flags for non-equality\n+ * \\param[in] other The second operand\n+ * \\return True if the Flags and \\a other are not equal, false otherwise\n+ */\n+\n+/**\n+ * \\fn Flags::operator Type() const\n+ * \\brief Convert the Flags to the underlying integer type\n+ * \\return The Flags value as an integer\n+ */\n+\n+/**\n+ * \\fn Flags::operator bool() const\n+ * \\brief Convert the Flags to a boolean\n+ * \\return True if at least one flag is set, false otherwise\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator&(E flag) const\n+ * \\brief Compute the bitwise AND of this Flags and the \\a flag\n+ * \\param[in] flag The second operand\n+ * \\return A Flags containing the result of the AND operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator&(Flags other) const\n+ * \\brief Compute the bitwise AND of this Flags and the \\a other Flags\n+ * \\param[in] other The second operand\n+ * \\return A Flags containing the result of the AND operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator|(E flag) const\n+ * \\brief Compute the bitwise OR of this Flags and the \\a flag\n+ * \\param[in] flag The second operand\n+ * \\return A Flags containing the result of the OR operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator|(Flags other) const\n+ * \\brief Compute the bitwise OR of this Flags and the \\a other Flags\n+ * \\param[in] other The second operand\n+ * \\return A Flags containing the result of the OR operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator^(E flag) const\n+ * \\brief Compute the bitwise XOR of this Flags and the \\a flag\n+ * \\param[in] flag The second operand\n+ * \\return A Flags containing the result of the XOR operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator^(Flags other) const\n+ * \\brief Compute the bitwise XOR of this Flags and the \\a other Flags\n+ * \\param[in] other The second operand\n+ * \\return A Flags containing the result of the XOR operation\n+ */\n+\n+/**\n+ * \\fn Flags Flags::operator~() const\n+ * \\brief Compute the bitwise NOT of this Flags\n+ * \\return A Flags containing the result of the NOT operation\n+ */\n+\n+/**\n+ * \\fn bool Flags::operator!() const\n+ * \\brief Check if flags are set\n+ * \\return True if no flags is set, false otherwise\n+ */\n+\n+/**\n+ * \\def LIBCAMERA_FLAGS_ENABLE_OPERATORS(enum)\n+ * \\brief Enable bitwise operations on the \\a enum enumeration\n+ *\n+ * This macro enables the bitwise AND, OR, XOR and NOT operators on the given\n+ * \\a enum. This allows the enum values to be safely used in bitwise operations\n+ * with the Flags<> class.\n+ */\n+\n+} /* namespace libcamera */\ndiff --git a/src/libcamera/base/meson.build b/src/libcamera/base/meson.build\nindex 871721571e98..d799c66d8b3a 100644\n--- a/src/libcamera/base/meson.build\n+++ b/src/libcamera/base/meson.build\n@@ -7,6 +7,7 @@ libcamera_base_sources = files([\n 'event_dispatcher_poll.cpp',\n 'event_notifier.cpp',\n 'file.cpp',\n+ 'flags.cpp',\n 'log.cpp',\n 'message.cpp',\n 'object.cpp',\n", "prefixes": [ "libcamera-devel", "v2", "1/5" ] }