[gdal-dev] RasterIO support for zlib / deflate compression?

[Even Rouault]

Brad,

> I've been looking at how much work it might take to implement a new NITF
> compression value (IC=CC and IC=MC) which is basically just ZLIB DEFLATE
> encoded blocks.

Is it your own codec or something already standardized in NITF ?
If the former, I'd suggest that you consider ZStandard [1] compression 
instead. It performs much better than ZLIB Deflate. I've integrated it 
recently as a TIFF codec

> 
> Before I start to dig around in zlib, is there any support in the RasterIO
> level to do this? Anything else I could copy before reimplementing it
> poorly?

Nothing at the RasterIO() level that exposes compressed datastream.
For ZLib(), there's a tiny helper, CPLZLibDeflate(), that can help you a bit.

Even

[1] https://github.com/facebook/zstd

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com