Read and Write IDL SAVE files!

[Craig Markwardt <craigmnet(at)cow.physics.wisc.edu>]

I am pleased to release a library for reading writing and
interrogating IDL SAVE files on my web page:

http://cow.physics.wisc.edu/~craigm/idl/idl.html

Interactive users will probably appreciate the ability of CMSAVEDIR to
list the contents of a SAVE file without restoring it.  I personally
find this procedure very useful, because I often create save files and
later forget what they contain.  You may find the download worth it
just for this feature!  They will also probably like the /APPEND
keyword of CMSAVE to append additional data to any SAVE file.

Programmers will probably use the library to write their own data, and
to read user's existing data.  The library provides higher-, middle-
and lower-level routines for reading writing and querying a SAVE file.
There are flexible ways to selectively save and restore variables
under programmatic control.  Using the CMSAVEDIR procedure it is
possible to extract a wealth of information about the save file
without actually reading the data.

The library supports all save file formats written by IDL version 4
and later.  However there are some caveats.  As we explored on this
newsgroup, it will not be possible to save and restore objects, but JD
Smith's solution will be greatly facilitated by the NAMED_CLASSES
keyword of CMSAVEDIR.  It is also not possible to read or write
compressed files, or files larger than 2 gigabytes.  Still I think
people will find a lot of applications for the library.

I encourage you to give it a try.  As usual, all the files are
documented, and the web page contains some overall documentation.  You
can get started almost right away, and some examples are provided on
the web page, listed under Questions and Answers.  The first thing you
can try is the CMSV_TEST procedure which will make sure you have a
fully functional library.  Hopefully there will be relatively few bugs
to shake out! :-)

Have fun with it,
Craig

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Craig B. Markwardt, Ph.D.         EMAIL:    craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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