[svn-r9101] Purpose:

    Bug fix

Description:
    1 - Dataset contiguous storage cache information had a bug where it was
possible to try to access invalid cache information if the cache wasn't filled
the first time it attempted to loop through the list of offset/length vectors.

    2 - Additionally, the contiguous storage cache information was being used
in certain circumstances from the chunked dataset I/O code path, which was
generally fatal since the chunk storage and contiguous storage information
were stored together in a union.


Solution:
    1 - Avoid special case of first trip through loop over offset/length
I/O vectors and always check for the contiguous storage sieve buffer buffer
being NULL.

    2 - Change the union containing the chunk and contiguous storage cache
information into a struct, allowing both to be used at the same time.


Platforms tested:
    FreeBSD 4.10 (sleipnir)
    h5committested

1 files changed, 5 insertions, 1 deletions

diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 30183c3..8b88e92 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -93,8 +93,12 @@ struct H5D_t {
     H5O_fill_t          fill;           /* Dataset fill value information */
 
     /* Buffered/cached information for types of raw data storage*/
-    union {
+    struct {
         H5D_rdcdc_t     contig;         /* Information about contiguous data */
+                                        /* (Note that the "contig" cache
+                                         * information can be used by a chunked
+                                         * dataset in certain circumstances)
+                                         */
         H5D_rdcc_t      chunk;          /* Information about chunked data */
     }cache;
 };