1) In the overview section performance is nowhere to be seen as a  goal, which for my use case is very important. If I were to use  the  binary archive, how well would it perform in comparsion to a  hand  crafted optimized serialization aproach? I've seen in the  examples  that strings seems to be used to identify data, won't  this create a  large overhead for both deserilzation and storage?

Performance is a secondary goal that I have worked on, especially the
serialization of large dense arrays. This is now as fast ad any hand
crafted approach. What data structures are you interested in?

Matthias

I'm reading a xml file into a custom tree data structure, parsing  the string representations into their correct types stored as  boost::any. I'm hoping that deserialization using boost::serialize  will be considerably faster than using libxml2 which I use to parse  the xml file. The node data in this structure pretty much looks like:

vector< DataCollection > children; // Naturally all the children of  this node
std::string name; // This is the tag name in xml
boost::any value; // This is <b>value</b> in xml
std::map< std::string, boost::any > attributes; // Not entirely  suprising the attributes of the xml node

The values stored in boost::any will be fairly lightweight, so I  would recon that the majority of data read will actually be  std::string for keys into the attributes as well as the name of the  node. So I guess I'm having a little bit of everything hehe.

Since I won't send this data over network, and if I make a build  for another system I can just ship different data files, I'm more  interested in speed and the flexibility which boost::serilization  offers. I'd be very interested in your changes Matthias.

There are not many optimizations for XML files: most of the overhead is
in parsing the strings. I you are interested in performance, a binary
archive will always be faster than an XML one. Most of the
optimizations for binary archives are already in Boost 1.35.

I have a couple of questions:

1. why are your attributes a std::map< std::string, boost::any >  and
not a std::map< std::string, std::string > ? How do you find out which
type to use?

2. why is your value a boost::any? How do you know the type to use?

When I parse the XML file with libxml2 I have a list where the different types have registered a regex filter which it will use to find the real type. Lets say you have for example <elem position="3 3 3">, then that will match the vector3 filter and construct a boost::any holding that vector3. I have a pretty neat system running here where I just need new types to register at FilterList. My DataCollection then have a Type& GetAttribute< Type >( const std::string& ), which basically wraps the any_cast and asserts that the typeids match. This way I get a pretty decent type safety, and since the client knows what type to expect it works out in the end.

I don't really know how boost::serialize works under the hood, but I was expecting to get healthy speed up due to:
A) libxml2 needs to parse the string data, locating start/end of xml elements, which I'm presuming is pretty costly in searching through all the string data.
B) When I use libxml2 it first parses data into a string, which I then need to extract and match at runtime to construct the real type.
C) I'm hoping the binary archive will take up less memory, resulting in less I/O. I strip the xml formating for example.

I'm also enteraining the thought of having much more complex objects stored from my application, kind of using the binary archive as a cache. I haven't really explored that area all that much yet though.

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