libcamera: vector: Add a Span based constructor

When one wants to create a Vector from existing data, currently the only
way is via std::array. Add a Span based constructor to allow creation
from std::vectors and alike.

While at it, replace the manual loop with std::copy.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/libcamera/vector.cpp

@@ -44,6 +44,14 @@ LOG_DEFINE_CATEGORY(Vector)
  * The size of \a data must be equal to the dimension size Rows of the vector.
  */
 
+/**
+ * \fn Vector::Vector(const Span<const T, Rows> data)
+ * \brief Construct vector from supplied data
+ * \param data Data from which to construct a vector
+ *
+ * The size of \a data must be equal to the dimension size Rows of the vector.
+ */
+
 /**
  * \fn T Vector::operator[](size_t i) const
  * \brief Index to an element in the vector