update to Dlang HDF5 format bindings/wrappers

[Laeeth Isharc via Digitalmars-d-announce]

What is HDF5, and why should you use it ?

http://www.hdfgroup.org/why_hdf/

(My summary):
   - very large data sets, very fast access requirements, and 
complex datasets
   - share data across variety of platforms
   - many open-source and commercial tools that understand HDF
   - self-describing and can specify complex data relationships 
and dependencies
   - can contain binary data in many representations
   - allow direct access to parts of file without first parsing 
whole contents
   - hierarchical data objects can be expressed in natural manner 
(contrast
     experience with realational database tables)
   - n-dimensional datasets and each element in set may be complex 
object
   - relational databases good for field matching queries but not 
for
     sequentially processing all records in database or for 
subsetting data
     based on co-ordinate style lookup
   - custom proprietary binary formats often not portable, not 
extensible and
     not high-performance.  technical debt to maintain data 
management part of
     code

I personally find it useful for storing price data for financial 
instruments, and also economic data.  There are bespoke time 
series databases, but they come at a price, which is not purely a 
pecuniary one.

Updated wrappers are here:
https://github.com/Laeeth/d_hdf5

Changes since last time - some fixes to bindings and updates to 
later version of HDF5 API.  There is more to go to make it 
accessible idiomatically from D, but it's usable today.  A simple 
example of mapping D structs to HDF5 types and back again is in 
the examples/traits directory.

Pull requests and offers to help maintain it are welcome.  It's 
still at an alpha stage, but already useful.



Laeeth.