Feature request for serialization
It would be nice to be able to specify a callback that can notify how far a serialization (at loading) has come. I have a structure that can take a LONG time to load, and it would be good to be able to present a progress bar for the user. /R
This would be something that would be better to do yourself. Here is a suggestion: Suppose you've got class A { B b; C c; D d; }; and class B { std::vector<E> ve; }; Suppose you want a call back every time something is serialized template<class Archive> void serialize(Archive & ar, E & e, const unsigned int version){ ar & e; my_callback_e(); // } template<class Archive> void serialize(Archive & ar, B & b, const unsigned int version){ ar & b; my_callback_b(); // } etc. If you wanted something more generc, you could make an archive adaptor which could add the same functionalty to any archive. Robert Ramey Robert Bielik wrote:
It would be nice to be able to specify a callback that can notify how far a serialization (at loading) has come. I have a structure that can take a LONG time to load, and it would be good to be able to present a progress bar for the user.
/R
On Thursday, October 18, 2007 at 09:01:06 (-0700) Robert Ramey writes:
This would be something that would be better to do yourself. Here is a suggestion:
Suppose you've got
class A { B b; C c; D d; };
I think something simpler would be to have a single callback, say progress(), and pass it the number of bytes read so far from the stream in question. This would allow a percentage complete calculation to be done based on the number of bytes in the incoming file (assuming it is not compressed). Thus, something like this: template<class Archive> void serialize(Archive & ar, E & e, const unsigned int version){ ar & e; progress(ar.stream().tellg()); } template<class Archive> void serialize(Archive & ar, B & b, const unsigned int version){ ar & b; progress(ar.stream().tellg()); } or whatever. If compressed, then you'll have to fudge things, dividing the bytes by some heuristic factor... Bill
Bill Lear:
I think something simpler would be to have a single callback, say progress(), and pass it the number of bytes read so far from the stream in question. This would allow a percentage complete calculation to be done based on the number of bytes in the incoming file (assuming it is not compressed). Thus, something like this:
template<class Archive> void serialize(Archive & ar, E & e, const unsigned int version){ ar & e; progress(ar.stream().tellg()); }
template<class Archive> void serialize(Archive & ar, B & b, const unsigned int version){ ar & b; progress(ar.stream().tellg()); }
or whatever.
It's better to implement the progress callback at the streambuf level, the stream level, or the archive level (in decreasing order of betterness.)
If you want to do it for a particular type of archive or applicaiton without messing up your serialization for all the others you could use void serialize(my_archive & ar, E & e, const unsigned int version){ ar & e; progress(e); } Then it would only be applied with you included that particular header. Might be useful for debugging or whatever. So your problem now is - you've got too many ideas to choose from. Robert Ramey Peter Dimov wrote:
Bill Lear:
I think something simpler would be to have a single callback, say progress(), and pass it the number of bytes read so far from the stream in question. This would allow a percentage complete calculation to be done based on the number of bytes in the incoming file (assuming it is not compressed). Thus, something like this:
template<class Archive> void serialize(Archive & ar, E & e, const unsigned int version){ ar & e; progress(ar.stream().tellg()); }
template<class Archive> void serialize(Archive & ar, B & b, const unsigned int version){ ar & b; progress(ar.stream().tellg()); }
or whatever.
It's better to implement the progress callback at the streambuf level, the stream level, or the archive level (in decreasing order of betterness.)
Robert Ramey skrev:
Then it would only be applied with you included that particular header. Might be useful for debugging or whatever.
So your problem now is - you've got too many ideas to choose from.
Yes, I see. I did however like the idea of having it at streambuf or stream level as I know how many bytes are in the stream. This I had in mind earlier also.
It's better to implement the progress callback at the streambuf level, the stream level, or the archive level (in decreasing order of betterness.)
Perhaps in betterness, but the lower you get, lesser the info. On the archive level, it would be possible to also include names of classes/members being serialized. But progress info will be sufficient. What I do is something like this: A a; boost::archive::xml_iarchive ia(stream); ia >> boost::serialization::make_nvp("xmldoc", A); where stream is std::istream& . I'm not sure where to hook into the stream (I'm no STL lowlevel expert). Should I make my own streambuf implementation? TIA /Rob
participants (4)
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Bill Lear -
Peter Dimov -
Robert Bielik -
Robert Ramey