{"id":10749,"url":"https://patchwork.libcamera.org/api/patches/10749/?format=json","web_url":"https://patchwork.libcamera.org/patch/10749/","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":"<20201227100331.1347-1-laurent.pinchart@ideasonboard.com>","date":"2020-12-27T10:03:31","name":"[libcamera-devel] libcamera: utils: Add reverse adapter for range-based loop","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"90459f9aac6d2d5414b1aa78ba75ca1f363b2622","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/?format=json","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"delegate":{"id":14,"url":"https://patchwork.libcamera.org/api/users/14/?format=json","username":"pinchartl","first_name":"Laurent","last_name":"Pinchart","email":"laurent.pinchart@ideasonboard.com"},"mbox":"https://patchwork.libcamera.org/patch/10749/mbox/","series":[{"id":1555,"url":"https://patchwork.libcamera.org/api/series/1555/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=1555","date":"2020-12-27T10:03:31","name":"[libcamera-devel] libcamera: utils: Add reverse adapter for range-based loop","version":1,"mbox":"https://patchwork.libcamera.org/series/1555/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/10749/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/10749/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 D9131C0F1A\n\tfor ;\n\tSun, 27 Dec 2020 10:03:46 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id A32AF60525;\n\tSun, 27 Dec 2020 11:03:46 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 69A4B6031F\n\tfor ;\n\tSun, 27 Dec 2020 11:03:45 +0100 (CET)","from pendragon.lan (62-78-145-57.bb.dnainternet.fi [62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id C28BD80B\n\tfor ;\n\tSun, 27 Dec 2020 11:03:44 +0100 (CET)"],"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=\"rWm9l1/W\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1609063425;\n\tbh=7Ur+R1j9PG8PYbMeeoLgITLBWJ9uwLX93OnqSh+hbQM=;\n\th=From:To:Subject:Date:From;\n\tb=rWm9l1/WyhDpEsYF7O1zE5QrBt4a1yoWdGiFX6I2OSwlDlKJNMiebQ23rbFJN8ymP\n\t6pO+b21sRGAW71nJ6RUIfdJ1CsEm4Cdxh7XKUmJcKfPx6Bys+SPbjJDx6b9PKu7TI+\n\tWp+XTrhsi3SE+UDodIsO2SK/qSxaMpWInrnk8jfU=","From":"Laurent Pinchart ","To":"libcamera-devel@lists.libcamera.org","Date":"Sun, 27 Dec 2020 12:03:31 +0200","Message-Id":"<20201227100331.1347-1-laurent.pinchart@ideasonboard.com>","X-Mailer":"git-send-email 2.27.0","MIME-Version":"1.0","Subject":"[libcamera-devel] [PATCH] libcamera: utils: Add reverse adapter for\n\trange-based loop","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","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Add a utils::reverse() function that creates an adapter wrapping in\niterable, such that range-based iteration over the adapter iterates over\nthe iterable in reverse order.\n\nSigned-off-by: Laurent Pinchart \n---\n include/libcamera/internal/utils.h | 27 +++++++++++++++++++++++++++\n src/libcamera/utils.cpp | 8 ++++++++\n 2 files changed, 35 insertions(+)\n\nThis will be used in an upcoming patch series, I'm already sending it\nout to get the idea reviewed.","diff":"diff --git a/include/libcamera/internal/utils.h b/include/libcamera/internal/utils.h\nindex f08134afb5ba..d0146b71727d 100644\n--- a/include/libcamera/internal/utils.h\n+++ b/include/libcamera/internal/utils.h\n@@ -203,6 +203,33 @@ constexpr unsigned int alignUp(unsigned int value, unsigned int alignment)\n \treturn (value + alignment - 1) / alignment * alignment;\n }\n \n+namespace details {\n+\n+template\n+struct reverse_adapter {\n+\tT &iterable;\n+};\n+\n+template\n+auto begin(reverse_adapter r)\n+{\n+\treturn std::rbegin(r.iterable);\n+}\n+\n+template\n+auto end(reverse_adapter r)\n+{\n+\treturn std::rend(r.iterable);\n+}\n+\n+} /* namespace details */\n+\n+template\n+details::reverse_adapter reverse(T &&iterable)\n+{\n+\treturn { iterable };\n+}\n+\n } /* namespace utils */\n \n } /* namespace libcamera */\ndiff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp\nindex e90375ae115c..c4098a74e0ab 100644\n--- a/src/libcamera/utils.cpp\n+++ b/src/libcamera/utils.cpp\n@@ -464,6 +464,14 @@ std::string libcameraSourcePath()\n * \\return The value rounded up to the nearest multiple of \\a alignment\n */\n \n+/**\n+ * \\fn reverse(T &&iterable)\n+ * \\brief Wrap an iterable to reverse iteration in a range-based loop\n+ * \\param[in] iterable The iterable\n+ * \\return A value of unspecified type that, when used in a range-based for\n+ * loop, will cause the loop to iterate over the \\a iterable in reverse order\n+ */\n+\n } /* namespace utils */\n \n } /* namespace libcamera */\n","prefixes":["libcamera-devel"]}