e97886a994
The dc_iostream_{read,write}() implementation had multiple issues:
(a) it would return DC_STATUS_SUCCESS even if no iostream
implementation existed.
Yes, it would also return a zero "actual" bytes, but most backends
don't even pass an "actual" pointer, so returning success was still
completely insane.
This one probably didn't matter, because all iostreams should have
read and write members, but the return value was completely wrong
if that ever were to happen.
(b) The write side actually tested not whether a write function
existed, but whether a read one existed.
Again, this one probably didn't matter in practice, since an
iostream without a read and write member doesn't make much sense,
but the test was completely wrong regardless.
(c) If the user passed in a NULL 'actual' pointer, the wrapper would
ignore that, and pass in its own pointer instead, in order to know
how many bytes to print for the debug message.
But that means that the low-level read/write functions cannot know
whether the user actually is able to handle a partial read or not.
This one _definitely_ matters, because some protocols need to have
a buffer for the whole incoming packet, but packerts may not always
be full-size. The low-level protocol needs to know whether to wait
for further packets (in order to fill the buffer) or to just return
the partial data.
This fixes all of these issues. If the user passes in a NULL actual
pointer (indicating that it needs all-or-nothing and is not ready to
handle a partial success), just loop over the IO until the buffer is
fully exhausted.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Overview ======== Libdivecomputer is a cross-platform and open source library for communication with dive computers from various manufacturers. The official web site is: http://www.libdivecomputer.org/ The sourceforge project page is: http://sourceforge.net/projects/libdivecomputer/ Installation ============ On UNIX-like systems (including Linux, Mac OS X, MinGW), use the autotools based build system. Run the following commands from the top directory (containing this file) to configure, build and install the library and utilities: $ ./configure $ make $ make install If you downloaded the libdivecomputer source code directly from the git source code repository, then you need to create the configure script as the first step: $ autoreconf --install To uninstall libdivecomputer again, run: $ make uninstall Support ======= Please send bug reports, feedback or questions to the mailing list: http://libdivecomputer.org/cgi-bin/mailman/listinfo/devel or contact me directly: jef@libdivecomputer.org License ======= Libdivecomputer is free software, released under the terms of the GNU Lesser General Public License (LGPL). You can find a copy of the license in the file COPYING.