Changeset 21535 for trunk/psLib

Timestamp:

Feb 18, 2009, 5:15:40 PM (17 years ago)

Author:

Paul Price

Message:

It seems to be impossible for us to directly write out U16 with PLIO
compression: it won't convert on the fly, and we can't convert
ourselves to S16 without introducing negative values (which PLIO can't
tolerate).
Therefore we converted U16 to S32 (and U32 to S64) before passing the
image on to cfitsio for PLIO compression. This is acceptable, so long
as the values used are less than 2^{24 (guaranteed for the U16
original).}

File:

• trunk/psLib/src/fits/psFitsImage.c (modified) (2 diffs)

trunk/psLib/src/fits/psFitsImage.c

@@ -7 +7 @@
  *  @author Robert DeSonia, MHPCC
  *
- *  @version $Revision: 1.41 $ $Name: not supported by cvs2svn $
- *  @date $Date: 2009-01-27 06:39:37 $
+ *  @version $Revision: 1.42 $ $Name: not supported by cvs2svn $
+ *  @date $Date: 2009-02-19 03:15:40 $
  *
  *  Copyright 2004-2005 Maui High Performance Computing Center, University of Hawaii
@@ -266 +266 @@
     *floatType = PS_FITS_FLOAT_NONE;
 
-    psFitsOptions *options = fits->options;
+    psFitsOptions *options = fits->options; // Options for FITS writing
+
+    // Can't PLIO compress U16,U32,U64 directly, so convert them
+    if (psFitsCompressionGetType(fits) == PS_FITS_COMPRESS_PLIO && (!options || options->bitpix == 0)) {
+        switch (image->type.type) {
+          case PS_TYPE_U16:
+            return psImageCopy(NULL, image, PS_TYPE_S32);
+          case PS_TYPE_U32:
+            return psImageCopy(NULL, image, PS_TYPE_S64);
+          case PS_TYPE_U64:
+            // Conversion would result in numerical overflow
+            psError(PS_ERR_IO, true, "Unable to compress U64 images");
+            return NULL;
+          default:
+            // No action
+            ;
+        }
+    }
+
     if (!options) {
         return psMemIncrRefCounter((psImage*)image); // Casting away const