libcamera: controls: Merge ControlInfoMap and V4L2ControlInfoMap

The ControlInfoMap and V4L2ControlInfoMap classes are very similar, with
the latter adding convenience accessors based on numerical IDs for the
former, as well as a cached idmap. Both features can be useful for
ControlInfoMap in the context of serialisation, and merging the two
classes will further simplify the IPA API.

Import all the features of V4L2ControlInfoMap into ControlInfoMap,
turning the latter into a real class. A few new constructors and
assignment operators are added for completeness.

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

1 files changed, 138 insertions, 1 deletions

diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index 6a0301f3..bf7634aa 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -393,9 +393,146 @@ std::string ControlRange::toString() const
  */
 
 /**
- * \typedef ControlInfoMap
+ * \class ControlInfoMap
  * \brief A map of ControlId to ControlRange
+ *
+ * The ControlInfoMap class describes controls supported by an object as an
+ * unsorted map of ControlId pointers to ControlRange instances. Unlike the
+ * standard std::unsorted_map<> class, it is designed the be immutable once
+ * constructed, and thus only exposes the read accessors of the
+ * std::unsorted_map<> base class.
+ *
+ * In addition to the features of the standard unsorted map, this class also
+ * provides access to the mapped elements using numerical ID keys. It maintains
+ * an internal map of numerical ID to ControlId for this purpose, and exposes it
+ * through the idmap() method to help construction of ControlList instances.
+ */
+
+/**
+ * \typedef ControlInfoMap::Map
+ * \brief The base std::unsorted_map<> container
+ */
+
+/**
+ * \fn ControlInfoMap::ControlInfoMap(const ControlInfoMap &other)
+ * \brief Copy constructor, construct a ControlInfoMap from a copy of \a other
+ * \param[in] other The other ControlInfoMap
+ */
+
+/**
+ * \brief Construct a ControlInfoMap from an initializer list
+ * \param[in] init The initializer list
+ */
+ControlInfoMap::ControlInfoMap(std::initializer_list<Map::value_type> init)
+	: Map(init)
+{
+	generateIdmap();
+}
+
+/**
+ * \fn ControlInfoMap &ControlInfoMap::operator=(const ControlInfoMap &other)
+ * \brief Copy assignment operator, replace the contents with a copy of \a other
+ * \param[in] other The other ControlInfoMap
+ * \return A reference to the ControlInfoMap
+ */
+
+/**
+ * \brief Replace the contents with those from the initializer list
+ * \param[in] init The initializer list
+ * \return A reference to the ControlInfoMap
+ */
+ControlInfoMap &ControlInfoMap::operator=(std::initializer_list<Map::value_type> init)
+{
+	Map::operator=(init);
+	generateIdmap();
+	return *this;
+}
+
+/**
+ * \brief Move assignment operator from a plain map
+ * \param[in] info The control info plain map
+ *
+ * Populate the map by replacing its contents with those of \a info using move
+ * semantics. Upon return the \a info map will be empty.
+ *
+ * \return A reference to the populated ControlInfoMap
+ */
+ControlInfoMap &ControlInfoMap::operator=(Map &&info)
+{
+	Map::operator=(std::move(info));
+	generateIdmap();
+	return *this;
+}
+
+/**
+ * \brief Access specified element by numerical ID
+ * \param[in] id The numerical ID
+ * \return A reference to the element whose ID is equal to \a id
  */
+ControlInfoMap::mapped_type &ControlInfoMap::at(unsigned int id)
+{
+	return at(idmap_.at(id));
+}
+
+/**
+ * \brief Access specified element by numerical ID
+ * \param[in] id The numerical ID
+ * \return A const reference to the element whose ID is equal to \a id
+ */
+const ControlInfoMap::mapped_type &ControlInfoMap::at(unsigned int id) const
+{
+	return at(idmap_.at(id));
+}
+
+/**
+ * \brief Count the number of elements matching a numerical ID
+ * \param[in] id The numerical ID
+ * \return The number of elements matching the numerical \a id
+ */
+ControlInfoMap::size_type ControlInfoMap::count(unsigned int id) const
+{
+	return count(idmap_.at(id));
+}
+
+/**
+ * \brief Find the element matching a numerical ID
+ * \param[in] id The numerical ID
+ * \return An iterator pointing to the element matching the numerical \a id, or
+ * end() if no such element exists
+ */
+ControlInfoMap::iterator ControlInfoMap::find(unsigned int id)
+{
+	return find(idmap_.at(id));
+}
+
+/**
+ * \brief Find the element matching a numerical ID
+ * \param[in] id The numerical ID
+ * \return A const iterator pointing to the element matching the numerical
+ * \a id, or end() if no such element exists
+ */
+ControlInfoMap::const_iterator ControlInfoMap::find(unsigned int id) const
+{
+	return find(idmap_.at(id));
+}
+
+/**
+ * \fn const ControlIdMap &ControlInfoMap::idmap() const
+ * \brief Retrieve the ControlId map
+ *
+ * Constructing ControlList instances for V4L2 controls requires a ControlIdMap
+ * for the V4L2 device that the control list targets. This helper method
+ * returns a suitable idmap for that purpose.
+ *
+ * \return The ControlId map
+ */
+
+void ControlInfoMap::generateIdmap()
+{
+	idmap_.clear();
+	for (const auto &ctrl : *this)
+		idmap_[ctrl.first->id()] = ctrl.first;
+}
 
 /**
  * \class ControlList