Re: [Boost-bugs] [Boost C++ Libraries] #4307: basic_oarchive optimization

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #4307: basic_oarchive optimization
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-06-08 05:58:50

#4307: basic_oarchive optimization
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 Reporter:  anonymous     |       Owner:  ramey        
     Type:  Patches       |      Status:  new          
Milestone:  Boost 1.43.0  |   Component:  serialization
  Version:  Boost 1.44.0  |    Severity:  Optimization 
 Keywords:                |  
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Comment(by anonymous):

 why? because of instantiation?

 the type_id itself can change between saving and loading, e.g. when
 loading an archive the internal type_id can be 5 while the class_id saved
 in the archive is 10.

 the type_id is only used for internal bookkeeping. before the patch the
 mapping was

 type_info -> cobject{ class_id }
 (through a std::set keyed on type_info)

 after the patch it is:

 type_info -> type_id -> cobject{ class_id }

 with type_id incidentally used as class_id, because I assumed the order of
 the class_id doesn't matter. but that can be changed, if you want the
 class_ids to be assigned sequentially.

 I think I'm going to map the type_ids to "cobject" by an intrusive
 unordered_map, too, though. that is almost as good as vector lookup(almost
 perfect hash function), and doesn't have the 10000-initialization problem
 described above.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4307#comment:5>
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