libcamera: controls: Support accessing controls by numerical ID

The ControlList class has template get() and set() methods to get and
set control values. The methods require a reference to a Control
instance, which is only available when calling them with a hardcoded
control. In order to support usage of ControlList for V4L2 controls, as
well as serialisation and deserialisation of ControlList, we need a way
to get and set control values based on a control numerical ID. Add new
contains(), get() and set() overload methods to do so.

As this change prepares the ControlList to be used for other objects
than camera, update its documentation accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

1 files changed, 8 insertions, 2 deletions

diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
index 999fcf7a..5e6708fe 100644
--- a/include/libcamera/controls.h
+++ b/include/libcamera/controls.h
@@ -126,7 +126,7 @@ private:
 	using ControlListMap = std::unordered_map<const ControlId *, ControlValue>;
 
 public:
-	ControlList(ControlValidator *validator = nullptr);
+	ControlList(const ControlIdMap &idmap, ControlValidator *validator = nullptr);
 
 	using iterator = ControlListMap::iterator;
 	using const_iterator = ControlListMap::const_iterator;
@@ -136,11 +136,13 @@ public:
 	const_iterator begin() const { return controls_.begin(); }
 	const_iterator end() const { return controls_.end(); }
 
-	bool contains(const ControlId &id) const;
 	bool empty() const { return controls_.empty(); }
 	std::size_t size() const { return controls_.size(); }
 	void clear() { controls_.clear(); }
 
+	bool contains(const ControlId &id) const;
+	bool contains(unsigned int id) const;
+
 	template<typename T>
 	const T &get(const Control<T> &ctrl) const
 	{
@@ -163,11 +165,15 @@ public:
 		val->set<T>(value);
 	}
 
+	const ControlValue &get(unsigned int id) const;
+	void set(unsigned int id, const ControlValue &value);
+
 private:
 	const ControlValue *find(const ControlId &id) const;
 	ControlValue *find(const ControlId &id);
 
 	ControlValidator *validator_;
+	const ControlIdMap *idmap_;
 	ControlListMap controls_;
 };