[svn-r8853] Purpose:

Code optimization

Description:
    Refactor B-tree code to extract all common information for a B-tree into a
shared structure that is pointed to by all the nodes in tree (instead of being
included in each node).

    Also re-order B-tree node comparison checks for chunked datasets to
check for >= the upper node first, since the comparison is a bit "heavy" and
this check is more likely to succeed when you are adding records to the
dataset.

Platforms tested:
    Solaris 2.7 (arabica)
    FreeBSD 4.10 (sleipnir) w/parallel
    Too minor to require h5committest
    (also, recent h5dump commits have broken testing...)

src/H5Bpkg.h

@@ -47,18 +47,12 @@
 struct H5B_t {
     H5AC_info_t cache_info; /* Information for H5AC cache functions, _must_ be */
                             /* first field in structure */
-    const H5B_class_t	*type;		/*type of tree			     */
-    size_t		sizeof_node;	/*size of raw (disk) node	     */
-    size_t		sizeof_rkey;	/*size of raw (disk) key	     */
-    size_t		total_native_keysize;	/*size of native keys	     */
+    H5RC_t		*rc_shared;	/*ref-counted shared info	     */
     unsigned		level;		/*node level			     */
     haddr_t		left;		/*address of left sibling	     */
     haddr_t		right;		/*address of right sibling	     */
     unsigned		nchildren;	/*number of child pointers	     */
-    H5RC_t		*rc_page;	/*ref-counted disk page		     */
-    uint8_t		*raw_page;	/*disk page (shared)		     */
     uint8_t		*native;	/*array of keys in native format     */
-    void		**nkey;		/*2k+1 key entries		     */
     haddr_t		*child;		/*2k child pointers		     */
 };