[Gdal-dev] Driver Implementation API - IReadBlock or IRasterIO

[Robert J Farmer]

Hello!

I am trying to develop a driver implementation for a propritary raster 
format.  Unfortunately, I am struggling with a few key concepts with the 
GDAL API.

The raster format contains a header followed by two bands of data which are 
pixel-interleaved (i.e.. B1P1, B2P1, B1P2, etc)  Band 1 contains float 
values, band 2 contains unsigned short values -- so both are 4 bytes long.

I believe that I should implement the IRasterIO interface (actually override 
it with BlockBasedRasterIO) to efficiently read the raster.  But what about 
the IReadBlock interface, do I need this?

I am unsure, when to implement IReadBlock and/or IRasterIO.  Any guidance 
would be greatly appreciated.

Cheers

Rob