Re: [netcdf-java] JNA Based NetCDF Access

• To: netcdf-java@xxxxxxxxxxxxxxxx
• Subject: Re: [netcdf-java] JNA Based NetCDF Access
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Mon, 12 Sep 2011 18:53:11 -0600

Wow, this is great, thanks Tisham!

Regards,

John

On 9/12/2011 6:07 PM, Tisham.Dhar@xxxxxxxx wrote:

Hi All,

I have successfully activated the JNA based C-library bridge by including
package: ucar.nc2.jni.netcdf , particularly these files: JniIosp.java,
NCLibrary.java . Thanks for the head start John. I have also tested on
Linux and Mac since the current code only loads DLL's by adding load calls
for .so and .dylibs as below.

             String osName = System.getProperty("os.name");
             boolean isWin = osName != null
                     &&  osName.toLowerCase().contains("win");
             boolean isMacOS = osName != null
                     &&  osName.toLowerCase().contains("mac");
             boolean isLinux = osName != null
                     &&  osName.toLowerCase().contains("linux");
             if(isWin)
             {
                 String dir = "C:/dev/tds/thredds/lib/binary/win32/";
                 System.setProperty("jna.library.path", dir);

                 System.load(dir + "zlib1.dll");
                 System.load(dir + "szlibdll.dll");
                 System.load(dir + "hdf5dll.dll");
                 System.load(dir + "hdf5_hldll.dll");
             }
             else if(isMacOS)
             {
                 String dir = "/opt/local/lib/";
                 System.setProperty("jna.library.path", dir);
                 System.load(dir + "libz.dylib");
                 System.load(dir + "libsz.dylib");
                 System.load(dir + "libhdf5.dylib");
                 System.load(dir + "libhdf5_hl.dylib");
             }
             else if(isLinux)
             {
                 String dir = "/usr/lib/";
                 System.setProperty("jna.library.path", dir);
                 System.load(dir + "x86_64-linux-gnu/libz.so");
             }

The timing benchmarks indicate that the access is faster across the board
than pure Java for sub 1GB files, you can read details of the benchmark
here: http://forum.worldwindcentral.com/showpost.php?p=97182&postcount=6 .
I am hoping that the JNA bindings to the C-library will move from
experimental to testing to production soon.

Cheers,

Tisham.


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• References:
  • Re: [netcdf-java] JNA Based NetCDF Access
    • From: Tisham.Dhar