[Gdal-dev] Virtualized IO Changes

[Frank Warmerdam]

Folks,

I am in the middle of substantial changes to the VSI (Virtual System
Interface) layer of GDAL so that I can read and write from non-filesystem
objects.  

While this is under constructions, GDAL CVS may be somewhat unstable.

The main objective of the new virtualization is to allow reading and writing
a variety of file formats to/from memory buffers.   The current approach
is to treat the "large file" API (ie. VSIFReadL, VSIFOpenL, etc) as
virtualizable.  New filesystem handlers can be installed with particular
subtrees of the filesystem.  Currently /vsimem/* is "owned" by the 
memory handler, and everything else is owned by the win32 or
unix stdio handler. 

One consequence of this change is that only file formats that exclusively
use the large file API for file access will be virtualizable.  I will be
modifying some of the drivers to do this as needed. 

Let me know if anyone runs into problems, or is interested in utilizing
this new feature. 

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent