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Netcdf data corruption after redef. (resend) address@hidden

Gentlemen:

You have reported problems with netcdf data corruption after
calling nc_redef/nc_endef.

Attached find a patch which I hope fixes the problem.
Please let me know if this works for you or not, so
we may proceed to roll this into a general release.

I apologise that this has taken so long.
We were unable to get a small example which demostrated the problem.

Thank you.

-glenn

Index: posixio.c
===================================================================
RCS file: /upc/share/CVS/netcdf-3/libsrc/posixio.c,v
retrieving revision 1.66
retrieving revision 1.67
diff -c -r1.66 -r1.67
*** posixio.c   1997/12/18 20:34:16     1.66
--- posixio.c   1999/04/23 23:02:41     1.67
***************
*** 2,8 ****
   *    Copyright 1996, University Corporation for Atmospheric Research
   *    See netcdf/COPYRIGHT file for copying and redistribution conditions.
   */
! /* $Id: posixio.c,v 1.66 1997/12/18 20:34:16 davis Exp $ */
  
  #include "ncconfig.h"
  #include <assert.h>
--- 2,8 ----
   *    Copyright 1996, University Corporation for Atmospheric Research
   *    See netcdf/COPYRIGHT file for copying and redistribution conditions.
   */
! /* $Id: posixio.c,v 1.67 1999/04/23 23:02:41 davis Exp $ */
  
  #include "ncconfig.h"
  #include <assert.h>
***************
*** 95,101 ****
        struct stat sb;
        if (fstat(fd, &sb) > -1)
        {
!               return (size_t) sb.st_blksize;
        }
        /* else, silent in the face of error */
  #endif
--- 95,103 ----
        struct stat sb;
        if (fstat(fd, &sb) > -1)
        {
!               if(sb.st_blksize >= 8192)
!                       return (size_t) sb.st_blksize;
!               return 8192;
        }
        /* else, silent in the face of error */
  #endif
***************
*** 501,508 ****
        void *src;
        void *dest;
        
! #if 0
! fprintf(stderr, "double_buffr %ld %ld %ld\n",
                 (long)to, (long)from, (long)nbytes);
  #endif
        status = px_get(nciop, pxp, to, nbytes, RGN_WRITE,
--- 503,510 ----
        void *src;
        void *dest;
        
! #if INSTRUMENT
! fprintf(stderr, "\tdouble_buffr %ld %ld %ld\n",
                 (long)to, (long)from, (long)nbytes);
  #endif
        status = px_get(nciop, pxp, to, nbytes, RGN_WRITE,
***************
*** 585,593 ****
--- 587,622 ----
        diff = (size_t)(upper - lower);
        extent = diff + nbytes;
  
+ #if INSTRUMENT
+ fprintf(stderr, "ncio_px_move %ld %ld %ld %ld %ld\n",
+                (long)to, (long)from, (long)nbytes, (long)lower, (long)extent);
+ #endif
        if(extent > pxp->blksz)
        {
                size_t remaining = nbytes;
+ 
+ if(to > from)
+ {
+               off_t frm = from + nbytes;
+               off_t toh = to + nbytes;
+               for(;;)
+               {
+                       size_t loopextent = MIN(remaining, pxp->blksz);
+                       frm -= loopextent;
+                       toh -= loopextent;
+ 
+                       status = px_double_buffer(nciop, toh, frm,
+                                       loopextent, rflags) ;
+                       if(status != ENOERR)
+                               return status;
+                       remaining -= loopextent;
+ 
+                       if(remaining == 0)
+                               break; /* normal loop exit */
+               }
+ }
+ else
+ {
                for(;;)
                {
                        size_t loopextent = MIN(remaining, pxp->blksz);
***************
*** 603,614 ****
                        to += loopextent;
                        from += loopextent;
                }
                return ENOERR;
        }
        
! #if 0
! fprintf(stderr, "ncio_px_move %ld %ld %ld %ld %ld\n",
!                (long)to, (long)from, (long)nbytes, (long)lower, (long)extent);
  #endif
        status = px_get(nciop, pxp, lower, extent, RGN_WRITE|rflags,
                        (void **)&base);
--- 632,643 ----
                        to += loopextent;
                        from += loopextent;
                }
+ }
                return ENOERR;
        }
        
! #if INSTRUMENT
! fprintf(stderr, "\tncio_px_move small\n");
  #endif
        status = px_get(nciop, pxp, lower, extent, RGN_WRITE|rflags,
                        (void **)&base);