The C++20 std::span class, after which Span is modelled, specifies four
constructors as explicit when extent is not dynamic_extent. Align our
implementation with those requirements.
A careful reviewer may notice that this change addresses five
constructors, not four. The reason is that the two constructors taking
Container and const Container parameters are not specified in C++20,
which uses a single constructor taking a range parameter instead. As
ranges are not available in C++17, the Container constructors are our
best effort at providing a similar feature.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
5aabf85d2c