Then we don't have to store copies of the 'formatted' and 'unified'
flags, and are also able to remove the 'prepareStep()' function. We
will reintroduce these features if we decide to add support for
keeping the output stream open between separate restart output
requests (i.e., between calls to EclipseIO::writeTimeStep()).
In particular, make the stream() function into a private detail of
the implementation and add an overload set for outputting keyword
data and messages to the underlying output stream. Update unit test
accordingly.
Suggested by: Atgeirr F. Rasmussen
This commit introduces a new class,
Opm::ecl::OutputStream::Restart
that handles the details of opening restart output streams (all
combinations of formatted/unformatted and unified/separate), as well
as correctly positioning the stream 'put' indicator if we're opening
an existing unified restart file. In most cases, this will be a
simple append operation (std::ios_base::app), but there are some
subtleties that require more precise control. The new class is
befriended by EclOutput and ERst in order to access private member
functions and data members of these classes. That is needed in
order to handle file resize operations since some of the requisite
information is only available in those two classes.
We use Boost.Filesystem to implement file resize, as if by POSIX
function ::truncate(), and also to simplify filename generation.
These calls can be switched to std::filesystem once the project
requires C++17.
Intended use of the Restart class is
Restart rst(resultSet, formatted, unified);
rst.prepareStep(17); // Report step/SEQNUM 17.
rst.write("INTEHEAD", ihead);
// ...
The 'prepareStep' operation opens the file stream (if needed) and
also outputs a SEQNUM record in the case of a unified output stream.
Moreover, the 'resultSet' is a pair of output directory and case's
base name (e.g., "./mpi.np4/2019.05.14.01" and "NORNE_ATW2013") and
the formatted/unified flags are bools wrapped in structures.
The Restart class is intended to take over the role of the
'filename' string parameter of RestartIO::save().
Add a set of unit tests to demontrate usage and abilities of class
Restart.
