[svn-r5168]

Purpose:
    H5Dset_extent API function
Description:

1 new public function: H5Dset_extent, that allows shrinking a dataset
several private functions that free the previously allocated chunks
H5F_istore_prune_by_extent, H5B_prune_by_extent : removes the chunks
H5F_istore_initialize_by_extent : initializes them with the fill value

H5S_select_fill is used to fill the selection in the memory buffer



Platforms tested:

    Windows 2000
    SUN( arabica)
    LINUX (eirene)
    IRIX64 (modi4)

1 files changed, 110 insertions, 0 deletions

diff --git a/src/H5B.c b/src/H5B.c
index 0adbca0..04993a1 100644
--- a/src/H5B.c
+++ b/src/H5B.c
@@ -2367,3 +2367,113 @@ H5B_assert(H5F_t *f, haddr_t addr, const H5B_class_t *type, void *udata)
     FUNC_LEAVE(SUCCEED);
 }
 #endif /* H5B_DEBUG */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5B_prune_by_extent
+ *
+ * Purpose: Search for chunks that are no longer necessary in the B-tree. 
+	*  The function iterates trough the B-tree and calls an operator function prune_extent
+ *
+ * Return: Success: 0, Failure: -1
+ *
+ * Programmer: Pedro Vicente, pvn@ncsa.uiuc.edu
+ *
+ * Date: March 26, 2002
+ *
+ * Comments: Private function
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+
+herr_t H5B_prune_by_extent( H5F_t *f, const H5B_class_t *type, haddr_t addr, void *udata, 
+																											 hsize_t *size )
+{
+ H5B_t    *bt = NULL;
+ haddr_t  next_addr;
+ haddr_t  cur_addr = HADDR_UNDEF;
+ uint8_t  *key = NULL;
+ int      i, nchildren;
+ herr_t   ret_value = FAIL;
+ 
+ FUNC_ENTER( H5B_prune_by_extent, FAIL);
+ 
+/*
+ * Check arguments.
+ */
+ assert( f );
+ assert( type );
+ assert( type->prune_extent);
+ assert( H5F_addr_defined( addr ) );
+ assert( udata );
+ 
+ if ( NULL == ( bt = H5AC_find( f, H5AC_BT, addr, type, udata ))) 
+	{
+  HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree node" );
+ }
+ 
+ if ( bt->level > 0 ) 
+ {
+  /* Keep following the left-most child until we reach a leaf node. */
+  if (( ret_value = H5B_prune_by_extent(f, type, bt->child[0], udata, size )) < 0 ) 
+		{
+   HGOTO_ERROR(H5E_BTREE, H5E_CANTLIST, FAIL, "unable to list B-tree node");
+  }
+ }
+ else 
+ {
+  
+/*
+ * We've reached the left-most leaf.  Now follow the right-sibling
+ * pointer from leaf to leaf until we've processed all leaves.
+ */
+  
+  if ( NULL== ( key = H5MM_malloc((2*H5B_Kvalue(f, type)+1)*type->sizeof_nkey ))) 
+		{
+   HGOTO_ERROR( H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed" );
+  }
+
+  for ( cur_addr = addr, ret_value = 0; H5F_addr_defined(cur_addr) && !ret_value; cur_addr = next_addr) 
+  {
+   
+ /*
+  * Save all the native keys since we can't leave the B-tree node protected during an application callback.
+  */
+   
+   if ( NULL == ( bt = H5AC_find( f, H5AC_BT, cur_addr, type, udata ))) 
+   {
+    HGOTO_ERROR( H5E_BTREE, H5E_CANTLOAD, FAIL, "B-tree node" );
+   }
+
+   for ( i = 0; i < bt->nchildren+1; i++ ) 
+   {
+    if ( !bt->key[i].nkey ) 
+     H5B_decode_key(f, bt, i);
+    HDmemcpy( key+i*type->sizeof_nkey, bt->key[i].nkey, type->sizeof_nkey );
+   }
+
+   next_addr = bt->right;
+   nchildren = bt->nchildren;
+   bt = NULL;
+ 
+			/* Figure out what chunks are no longer in use for the specified extent and release them */
+
+   for ( i = 0, ret_value = 0; i < nchildren && !ret_value; i++ ) 
+   {
+    ret_value = ( type->prune_extent )( f, key+i*type->sizeof_nkey, addr, udata, size );
+    if ( ret_value < 0 ) 
+				{
+     HGOTO_ERROR( H5E_BTREE, H5E_CANTINIT, FAIL, "iterator function failed" );
+    }
+   } /*i*/
+  } /*addr*/
+ } /*level*/
+ 
+done:
+ if( key != NULL )
+  H5MM_xfree( key );
+ FUNC_LEAVE( ret_value );
+}
+