[svn-r13001] Enabled CORE file driver to read or write an existing file depending

the setting of backing store through H5Pset_core_fapl and file open
flag.  Added test cases in vfd.c.

1 files changed, 54 insertions, 9 deletions

diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index cbbda53..b27949b 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -49,6 +49,7 @@ typedef struct H5FD_core_t {
     haddr_t	eoa;			/*end of allocated region	*/
     haddr_t	eof;			/*current allocated size	*/
     size_t	increment;		/*multiples for mem allocation	*/
+    hbool_t	backing_store;		/*write to file name on flush	*/
     int		fd;			/*backing store file descriptor	*/
     hbool_t	dirty;			/*changes not saved?		*/
 } H5FD_core_t;
@@ -368,23 +369,29 @@ done:
  * Modifications:
  *		Robb Matzke, 1999-10-19
  *		The backing store file is created and opened if specified.
+ *              
+ *              Raymond Lu, 2006-11-30
+ *              Enabled the driver to read an existing file depending on 
+ *              the setting of the backing_store and file open flags.
  *-------------------------------------------------------------------------
  */
 static H5FD_t *
-H5FD_core_open(const char *name, unsigned UNUSED flags, hid_t fapl_id,
+H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
 	       haddr_t maxaddr)
 {
+    int			o_flags;
     H5FD_core_t		*file=NULL;
     H5FD_core_fapl_t	*fa=NULL;
     H5P_genplist_t *plist;      /* Property list pointer */
+    h5_stat_t		sb;
     int			fd=-1;
     H5FD_t		*ret_value;
 
     FUNC_ENTER_NOAPI(H5FD_core_open, NULL)
 
     /* Check arguments */
-    if (!(H5F_ACC_CREAT & flags))
-        HGOTO_ERROR(H5E_ARGS, H5E_UNSUPPORTED, NULL, "must create core files, not open them")
+    if (!name || !*name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name")
     if (0==maxaddr || HADDR_UNDEF==maxaddr)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr")
     if (ADDR_OVERFLOW(maxaddr))
@@ -395,10 +402,18 @@ H5FD_core_open(const char *name, unsigned UNUSED flags, hid_t fapl_id,
         fa = H5P_get_driver_info(plist);
     } /* end if */
 
-    /* Open backing store */
-    if (fa && fa->backing_store && name &&
-            (fd=HDopen(name, (O_CREAT|O_TRUNC|O_RDWR), 0666))<0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open backing store")
+    /* Build the open flags */
+    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
+    if (H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
+    if (H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
+    if (H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
+
+    /* Open backing store.  The only case that backing store is off is when
+     * the backing_store flag is off and H5F_ACC_CREAT is on. */
+    if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
+        if (fa && (fd=HDopen(name, o_flags, 0666))<0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
+    }
 
     /* Create the new file struct */
     if (NULL==(file=H5MM_calloc(sizeof(H5FD_core_t))))
@@ -414,6 +429,34 @@ H5FD_core_open(const char *name, unsigned UNUSED flags, hid_t fapl_id,
      */
     file->increment = (fa && fa->increment>0) ?  fa->increment : H5FD_CORE_INCREMENT;
 
+    /* If save data in backing store. */
+    file->backing_store = fa->backing_store;
+
+    /* If an existing file is opened, load the whole file into memory. */
+    if(!(H5F_ACC_CREAT & flags)) {
+        unsigned char *x;
+        size_t size;
+
+        if (HDfstat(file->fd, &sb)<0)
+            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
+
+	size = (size_t)sb.st_size;
+
+        if(size) {
+            if (NULL==file->mem)
+                x = (unsigned char*)H5MM_malloc(size);
+
+            if (!x)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate memory block")
+
+            file->mem = x;
+            file->eof = size;
+
+            if(HDread(file->fd, file->mem, size)<0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read file")
+        }
+    }
+
     /* Set return value */
     ret_value=(H5FD_t *)file;
 
@@ -808,7 +851,9 @@ done:
  *              Friday, October 15, 1999
  *
  * Modifications:
- *
+ *              Raymond Lu, 2006-11-30
+ *              Added a condition check for backing store flag, for an
+ *              existing file can be opened for read and write now. 
  *-------------------------------------------------------------------------
  */
 /* ARGSUSED */
@@ -821,7 +866,7 @@ H5FD_core_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing)
     FUNC_ENTER_NOAPI(H5FD_core_flush, FAIL)
 
     /* Write to backing store */
-    if (file->dirty && file->fd>=0) {
+    if (file->dirty && file->fd>=0 && file->backing_store) {
         haddr_t size = file->eof;
         unsigned char *ptr = file->mem;