Changeset 23724 for trunk/Ohana/src/libfits/matrix/F_uncompress_data.c

Timestamp:

Apr 7, 2009, 12:45:31 PM (17 years ago)

Author:

eugene

Message:

handle images compressed with CFITSIO gzip compression

File:

• trunk/Ohana/src/libfits/matrix/F_uncompress_data.c (modified) (2 diffs)

trunk/Ohana/src/libfits/matrix/F_uncompress_data.c

@@ -22 +22 @@
 int pl_l2pi (short *ll_src, int xs, int *px_dst, int npix);
 
+/* functions defined in gzip.c */
+int gfits_gz_stripheader (unsigned char *data, int *ndata);
+int gfits_uncompress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen);
+
 int gfits_uncompress_data (char *zdata, int Nzdata, char *cmptype, char **optname, char **optvalue, int Nopt, char *outdata, int *Nout, int out_pixsize) {
 
@@ -30 +34 @@
   if (!strcasecmp(cmptype, "GZIP_1")) {
     unsigned long tNout = *Nout * out_pixsize;
+
+    // for GZIP data, I need to check for and remove the header on the first block:
+    gfits_gz_stripheader ((unsigned char *)zdata, &Nzdata);
+
     // uncompress does not require us to know the expected number of pixel; it tells us the number
-    status = uncompress ((Bytef *) outdata, &tNout, (Bytef *) zdata, Nzdata);
+    status = gfits_uncompress ((Bytef *) outdata, &tNout, (Bytef *) zdata, Nzdata);
     if (status != Z_OK) {
       fprintf (stderr, "error in uncompress (GZIP)\n");
       return (FALSE);
     }
-    *Nout = tNout;
+
+    // the resulting uncompressed data is byteswapped
+    if (!gfits_byteswap_zdata (outdata, tNout, out_pixsize)) return (FALSE);
+
+    *Nout = tNout / out_pixsize;
     return (TRUE);
   }