Re: [Jsoncpp-devel] Example code for Jsoncpp library

[Baptiste L. <bap...@gm...>]

2010/9/15 Anath Bandhu Mandal <a_b...@ya...>

> Hi
>
> I have been using the jsoncpp library, but having difficulties to
> understand how to effectively read/write data using Json::Value objects. You
> have give one example on http://jsoncpp.sourceforge.net/index.html, which
> does not explore much of the classes on how are they should be used. For
> example, I want to store about 4K of data with separator in one array,
> but this array should be added for a million records for read/write.
> However, I don't find an effective to way utilize this library due to
> limited example code.
>
> Could you please provide some example code on how to effective utilize the
> member functions for Json::Value, Json::Reader, and Json::Writer please?
>

You can look at the code of the jsontestrunner that is used for testing
reader/writer (e.g. it reads a json file, and rewrite it in json, as well as
a custom format).

That being said, I don't think jsoncpp is a good choice of library for your
use case: if I understood correctly (not sure what you mean by data with
separator), you want to parse 4K * 1M values. Because the parser will load
the whole json file in memory, a lot of memory is going to be wasted (I'm
not even sure you will be able to fit the Json::Value tree in memory after
conversion: 4K*1M=4*10**9 => means about 4GB of memory required if each
value needed only 1 byte!). Writing should not be an issue as you can use
the stream based writer that allow incremental writing to file.

Baptiste.


> Thanks,
> AB Mandal
>
>