[{"id":28976,"web_url":"https://patchwork.libcamera.org/comment/28976/","msgid":"<171049925034.1011926.15922775669483463775@ping.linuxembedded.co.uk>","date":"2024-03-15T10:40:50","subject":"Re: [PATCH v2 08/14] libcamera: v4l2_subdevice: Replace\n\tRouting::toString() with operator<<()","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Laurent Pinchart (2024-03-15 00:16:07)\n> The main (and only at the moment) use case for the Routing::toString()\n> function is to print a representation of the routing table in a log\n> message. The function is implemented using an std::stringstream, and the\n> returned std::string is then inserted into an std::ostream. This is\n> inefficient. Replace the function with a specialization of the\n> operator<<() and use it in the caller.\n> \n> Signed-off-by: Laurent Pinchart \n> Reviewed-by: Jacopo Mondi \n\n\nReviewed-by: Kieran Bingham \n\n> ---\n> include/libcamera/internal/v4l2_subdevice.h | 7 ++---\n> src/libcamera/pipeline/simple/simple.cpp | 2 +-\n> src/libcamera/v4l2_subdevice.cpp | 29 +++++++++++----------\n> 3 files changed, 18 insertions(+), 20 deletions(-)\n> \n> diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h\n> index 6cd36730371a..2939dc2411c6 100644\n> --- a/include/libcamera/internal/v4l2_subdevice.h\n> +++ b/include/libcamera/internal/v4l2_subdevice.h\n> @@ -95,11 +95,7 @@ public:\n> unsigned int stream;\n> };\n> \n> - class Routing : public std::vector\n> - {\n> - public:\n> - std::string toString() const;\n> - };\n> + using Routing = std::vector;\n> \n> explicit V4L2Subdevice(const MediaEntity *entity);\n> ~V4L2Subdevice();\n> @@ -178,5 +174,6 @@ static inline bool operator!=(const V4L2Subdevice::Stream &lhs,\n> }\n> \n> std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Stream &stream);\n> +std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Routing &routing);\n> \n> } /* namespace libcamera */\n> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp\n> index 3d0424969a89..feea26fd124f 100644\n> --- a/src/libcamera/pipeline/simple/simple.cpp\n> +++ b/src/libcamera/pipeline/simple/simple.cpp\n> @@ -1388,7 +1388,7 @@ int SimplePipelineHandler::resetRoutingTable(V4L2Subdevice *subdev)\n> \n> LOG(SimplePipeline, Debug)\n> << \"Routing table of \" << subdev->deviceNode()\n> - << \" reset to \" << routing.toString();\n> + << \" reset to \" << routing;\n> \n> return 0;\n> }\n> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp\n> index cc079425bb16..deef681e0d3a 100644\n> --- a/src/libcamera/v4l2_subdevice.cpp\n> +++ b/src/libcamera/v4l2_subdevice.cpp\n> @@ -899,30 +899,31 @@ std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Stream &stream)\n> }\n> \n> /**\n> - * \\class V4L2Subdevice::Routing\n> + * \\typedef V4L2Subdevice::Routing\n> * \\brief V4L2 subdevice routing table\n> *\n> * This class stores a subdevice routing table as a vector of routes.\n> */\n> \n> /**\n> - * \\brief Assemble and return a string describing the routing table\n> - * \\return A string describing the routing table\n> + * \\brief Insert a text representation of a V4L2Subdevice::Routing into an\n> + * output stream\n> + * \\param[in] out The output stream\n> + * \\param[in] routing The V4L2Subdevice::Routing\n> + * \\return The output stream \\a out\n> */\n> -std::string V4L2Subdevice::Routing::toString() const\n> +std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Routing &routing)\n> {\n> - std::stringstream routing;\n> -\n> - for (const auto &[i, route] : utils::enumerate(*this)) {\n> - routing << \"[\" << i << \"] \"\n> - << route.sink_pad << \"/\" << route.sink_stream << \" -> \"\n> - << route.source_pad << \"/\" << route.source_stream\n> - << \" (\" << utils::hex(route.flags) << \")\";\n> - if (i != size() - 1)\n> - routing << \", \";\n> + for (const auto &[i, route] : utils::enumerate(routing)) {\n> + out << \"[\" << i << \"] \"\n> + << route.sink_pad << \"/\" << route.sink_stream << \" -> \"\n> + << route.source_pad << \"/\" << route.source_stream\n> + << \" (\" << utils::hex(route.flags) << \")\";\n> + if (i != routing.size() - 1)\n> + out << \", \";\n> }\n> \n> - return routing.str();\n> + return out;\n> }\n> \n> /**\n> -- \n> Regards,\n> \n> Laurent Pinchart\n>","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 BE1CFBD160\n\tfor ;\n\tFri, 15 Mar 2024 10:40:54 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 71DC362C8C;\n\tFri, 15 Mar 2024 11:40:54 +0100 (CET)","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 18BD16295D\n\tfor ;\n\tFri, 15 Mar 2024 11:40:53 +0100 (CET)","from pendragon.ideasonboard.com\n\t(aztw-30-b2-v4wan-166917-cust845.vm26.cable.virginm.net\n\t[82.37.23.78])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 43692B3;\n\tFri, 15 Mar 2024 11:40:29 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; 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