path: root/src/H5G.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:	H5G.c
 *		Jul 18 1997
 *		Robb Matzke <matzke@llnl.gov>
 *
 * Purpose:	Symbol table functions.	 The functions that begin with
 *		`H5G_stab_' don't understand the naming system; they operate
 * 		on a single symbol table at a time.
 *
 *		The functions that begin with `H5G_node_' operate on the leaf
 *		nodes of a symbol table B-tree.  They should be defined in
 *		the H5Gnode.c file.
 *
 *		The remaining functions know how to traverse the group
 *		directed graph.
 *
 * Names:	Object names are a slash-separated list of components.  If
 *		the name begins with a slash then it's absolute, otherwise
 *		it's relative ("/foo/bar" is absolute while "foo/bar" is
 *		relative).  Multiple consecutive slashes are treated as
 *		single slashes and trailing slashes are ignored.  The special
 *		case `/' is the root group.  Every file has a root group.
 *
 *		API functions that look up names take a location ID and a
 *		name.  The location ID can be a file ID or a group ID and the
 *		name can be relative or absolute.
 *
 *              +--------------+----------- +--------------------------------+
 * 		| Location ID  | Name       | Meaning                        |
 *              +--------------+------------+--------------------------------+
 * 		| File ID      | "/foo/bar" | Find `foo' within `bar' within |
 *		|              |            | the root group of the specified|
 *		|              |            | file.                          |
 *              +--------------+------------+--------------------------------+
 * 		| File ID      | "foo/bar"  | Find `foo' within `bar' within |
 *		|              |            | the root group of the specified|
 *		|              |            | file.                          |
 *              +--------------+------------+--------------------------------+
 * 		| File ID      | "/"        | The root group of the specified|
 *		|              |            | file.                          |
 *              +--------------+------------+--------------------------------+
 * 		| File ID      | "."        | The root group of the specified|
 *		|              |            | the specified file.            |
 *              +--------------+------------+--------------------------------+
 * 		| Group ID     | "/foo/bar" | Find `foo' within `bar' within |
 *		|              |            | the root group of the file     |
 *		|              |            | containing the specified group.|
 *              +--------------+------------+--------------------------------+
 * 		| Group ID     | "foo/bar"  | File `foo' within `bar' within |
 *		|              |            | the specified group.           |
 *              +--------------+------------+--------------------------------+
 * 		| Group ID     | "/"        | The root group of the file     |
 *		|              |            | containing the specified group.|
 *              +--------------+------------+--------------------------------+
 * 		| Group ID     | "."        | The specified group.           |
 *              +--------------+------------+--------------------------------+
 *
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/

#define H5G_PACKAGE		/*suppress error about including H5Gpkg   */

/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC	H5G_init_interface


/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5ACprivate.h"	/* Metadata cache			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Gpkg.h"		/* Groups		  		*/
#include "H5Iprivate.h"		/* IDs			  		*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Pprivate.h"         /* Property lists                       */
#include "H5VLprivate.h"	/* VOL plugins				*/

/****************/
/* Local Macros */
/****************/


/******************/
/* Local Typedefs */
/******************/


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/


/*********************/
/* Package Variables */
/*********************/


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/

/* Group ID class */
static const H5I_class_t H5I_GROUP_CLS[1] = {{
    H5I_GROUP,			/* ID class value */
    0,				/* Class flags */
    64,				/* Minimum hash size for class */
    0,				/* # of reserved IDs for class */
    NULL,                 	/* Callback routine for closing objects of this class */
    (H5I_free2_t)H5G_close_group /* Callback routine for closing auxilary objects of this class */
}};



/*-------------------------------------------------------------------------
 * Function:	H5G__init
 *
 * Purpose:	Initialize the interface from some other package.
 *
 * Return:	Success:	non-negative
 *		Failure:	negative
 *
 * Programmer:	Quincey Koziol
 *              Saturday, November 11, 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5G__init(void)
{
    herr_t ret_value = SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(FAIL)
    /* FUNC_ENTER() does all the work */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5G__init() */


/*-------------------------------------------------------------------------
 * Function:	H5G_init_interface
 *
 * Purpose:	Initializes the H5G interface.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Monday, January	 5, 1998
 *
 * Notes:       The group creation properties are registered in the property
 *              list interface initialization routine (H5P_init_interface)
 *              so that the file creation property class can inherit from it
 *              correctly. (Which allows the file creation property list to
 *              control the group creation properties of the root group of
 *              a file) QAK - 24/10/2005
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5G_init_interface(void)
{
    herr_t          ret_value = SUCCEED;  /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Initialize the atom group for the group IDs */
    if(H5I_register_type(H5I_GROUP_CLS) < 0)
	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to initialize interface")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5G_init_interface() */


/*-------------------------------------------------------------------------
 * Function:	H5G_term_interface
 *
 * Purpose:	Terminates the H5G interface
 *
 * Return:	Success:	Positive if anything is done that might
 *				affect other interfaces; zero otherwise.
 *
 * 		Failure:	Negative.
 *
 * Programmer:	Robb Matzke
 *		Monday, January	 5, 1998
 *
 *-------------------------------------------------------------------------
 */
int
H5G_term_interface(void)
{
    int	n = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if(H5_interface_initialize_g) {
	if((n = H5I_nmembers(H5I_GROUP)))
	    H5I_clear_type(H5I_GROUP, FALSE, FALSE);
	else {
	    /* Destroy the group object id group */
	    H5I_dec_type_ref(H5I_GROUP);

	    /* Mark closed */
	    H5_interface_initialize_g = 0;
	    n = 1; /*H5I*/
	} /* end else */
    } /* end if */

    FUNC_LEAVE_NOAPI(n)
} /* end H5G_term_interface() */


/*-------------------------------------------------------------------------
 * Function:	H5Gcreate2
 *
 * Purpose:	Creates a new group relative to LOC_ID, giving it the
 *              specified creation property list GCPL_ID and access
 *              property list GAPL_ID.  The link to the new group is
 *              created with the LCPL_ID.
 *
 * Usage:       H5Gcreate2(loc_id, char *name, lcpl_id, gcpl_id, gapl_id)
 *                  hid_t loc_id;	  IN: File or group identifier
 *                  const char *name; IN: Absolute or relative name of the new group
 *                  hid_t lcpl_id;	  IN: Property list for link creation
 *                  hid_t gcpl_id;	  IN: Property list for group creation
 *                  hid_t gapl_id;	  IN: Property list for group access
 *
 * Return:	Success:	The object ID of a new, empty group open for
 *				writing.  Call H5Gclose() when finished with
 *				the group.
 *
 *		Failure:	FAIL
 *
 * Programmer:  Quincey Koziol
 *	        April 5, 2007
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Gcreate2(hid_t loc_id, const char *name, hid_t lcpl_id, hid_t gcpl_id, hid_t gapl_id)
{
    void    *grp = NULL;       /* dset token from VOL plugin */
    void    *obj = NULL;        /* object token of loc_id */
    H5VL_t  *vol_plugin;        /* VOL plugin information */
    H5VL_loc_params_t loc_params;
    H5P_genplist_t  *plist;            /* Property list pointer */
    hid_t	    ret_value;          /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE5("i", "i*siii", loc_id, name, lcpl_id, gcpl_id, gapl_id);

    /* Check arguments */
    if(!name || !*name)
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")

    /* Get correct property list */
    if(H5P_DEFAULT == lcpl_id)
        lcpl_id = H5P_LINK_CREATE_DEFAULT;
    else
        if(TRUE != H5P_isa_class(lcpl_id, H5P_LINK_CREATE))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not link creation property list")

    /* Check group creation property list */
    if(H5P_DEFAULT == gcpl_id)
        gcpl_id = H5P_GROUP_CREATE_DEFAULT;
    else
        if(TRUE != H5P_isa_class(gcpl_id, H5P_GROUP_CREATE))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not group create property list")

    /* Check the group access property list */
    if(H5P_DEFAULT == gapl_id)
        gapl_id = H5P_GROUP_ACCESS_DEFAULT;
    else
        if(TRUE != H5P_isa_class(gapl_id, H5P_GROUP_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not group access property list")

    /* Get the plist structure */
    if(NULL == (plist = (H5P_genplist_t *)H5I_object(gcpl_id)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    if(H5P_set(plist, H5VL_GRP_LCPL_ID, &lcpl_id) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for lcpl id")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the file object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")

    /* Create the group through the VOL */
    if(NULL == (grp = H5VL_group_create(obj, loc_params, vol_plugin, name, gcpl_id, gapl_id, H5_REQUEST_NULL)))
	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create group")

    /* Get an atom for the group */
    if((ret_value = H5I_register2(H5I_GROUP, grp, vol_plugin, TRUE)) < 0)
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize dataset handle")

done:
    if (ret_value < 0 && grp)
        if(H5VL_group_close (grp, vol_plugin, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to release group")
    FUNC_LEAVE_API(ret_value)
} /* end H5Gcreate2() */


/*-------------------------------------------------------------------------
 * Function:	H5Gcreate_anon
 *
 * Purpose:	Creates a new group relative to LOC_ID, giving it the
 *              specified creation property list GCPL_ID and access
 *              property list GAPL_ID.
 *
 *              The resulting ID should be linked into the file with
 *              H5Olink or it will be deleted when closed.
 *
 *              Given the default setting, H5Gcreate_anon() followed by
 *              H5Olink() will have the same function as H5Gcreate2().
 *
 * Usage:       H5Gcreate_anon(loc_id, char *name, gcpl_id, gapl_id)
 *                  hid_t loc_id;	  IN: File or group identifier
 *                  const char *name; IN: Absolute or relative name of the new group
 *                  hid_t gcpl_id;	  IN: Property list for group creation
 *                  hid_t gapl_id;	  IN: Property list for group access
 *
 * Example:	To create missing groups "A" and "B01" along the given path "/A/B01/grp"
 *              hid_t create_id = H5Pcreate(H5P_GROUP_CREATE);
 *              int   status = H5Pset_create_intermediate_group(create_id, TRUE);
 *              hid_t gid = H5Gcreate_anon(file_id, "/A/B01/grp", create_id, H5P_DEFAULT);
 *
 * Return:	Success:	The object ID of a new, empty group open for
 *				writing.  Call H5Gclose() when finished with
 *				the group.
 *
 *		Failure:	FAIL
 *
 * Programmer:  Peter Cao
 *	        May 08, 2005
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Gcreate_anon(hid_t loc_id, hid_t gcpl_id, hid_t gapl_id)
{
    void    *grp = NULL;       /* dset token from VOL plugin */
    void    *obj = NULL;        /* object token of loc_id */
    H5VL_t  *vol_plugin;        /* VOL plugin information */
    H5VL_loc_params_t loc_params;
    hid_t	    ret_value;

    FUNC_ENTER_API(FAIL)
    H5TRACE3("i", "iii", loc_id, gcpl_id, gapl_id);

    /* Check group creation property list */
    if(H5P_DEFAULT == gcpl_id)
        gcpl_id = H5P_GROUP_CREATE_DEFAULT;
    else
        if(TRUE != H5P_isa_class(gcpl_id, H5P_GROUP_CREATE))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not group create property list")

    /* Check the group access property list */
    if(H5P_DEFAULT == gapl_id)
        gapl_id = H5P_GROUP_ACCESS_DEFAULT;
    else
        if(TRUE != H5P_isa_class(gapl_id, H5P_GROUP_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not group access property list")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the file object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")

    /* Create the group through the VOL */
    if(NULL == (grp = H5VL_group_create(obj, loc_params, vol_plugin, NULL, gcpl_id, gapl_id, H5_REQUEST_NULL)))
	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create group")

    /* Get an atom for the group */
    if((ret_value = H5I_register2(H5I_GROUP, grp, vol_plugin, TRUE)) < 0)
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize dataset handle")

done:
    if (ret_value < 0 && grp)
        if(H5VL_group_close (grp, vol_plugin, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to release group")
    FUNC_LEAVE_API(ret_value)
} /* end H5Gcreate_anon() */


/*-------------------------------------------------------------------------
 * Function:	H5Gopen2
 *
 * Purpose:	Opens an existing group for modification.  When finished,
 *		call H5Gclose() to close it and release resources.
 *
 *              This function allows the user the pass in a Group Access
 *              Property List, which H5Gopen1() does not.
 *
 * Return:	Success:	Object ID of the group.
 *		Failure:	FAIL
 *
 * Programmer:	James Laird
 *		Thursday, July 27, 2006
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Gopen2(hid_t loc_id, const char *name, hid_t gapl_id)
{
    void    *grp = NULL;       /* dset token from VOL plugin */
    void    *obj = NULL;        /* object token of loc_id */
    H5VL_t  *vol_plugin;        /* VOL plugin information */
    H5VL_loc_params_t loc_params;
    hid_t       ret_value;              /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("i", "i*si", loc_id, name, gapl_id);

    /* Check args */
    if(!name || !*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")

    /* Check the group access property list */
    if(H5P_DEFAULT == gapl_id)
        gapl_id = H5P_GROUP_ACCESS_DEFAULT;
    else
        if(TRUE != H5P_isa_class(gapl_id, H5P_GROUP_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not group access property list")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the file object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")

    /* Create the group through the VOL */
    if(NULL == (grp = H5VL_group_open(obj, loc_params, vol_plugin, name, gapl_id, H5_REQUEST_NULL)))
	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create group")

    /* Get an atom for the group */
    if((ret_value = H5I_register2(H5I_GROUP, grp, vol_plugin, TRUE)) < 0)
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize dataset handle")

done:
    if (ret_value < 0 && grp)
        if(H5VL_group_close (grp, vol_plugin, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to release group")
    FUNC_LEAVE_API(ret_value)
} /* end H5Gopen2() */


/*-------------------------------------------------------------------------
 * Function:	H5Gget_create_plist
 *
 * Purpose:	Returns a copy of the group creation property list.
 *
 * Return:	Success:	ID for a copy of the group creation
 *				property list.  The property list ID should be
 *				released by calling H5Pclose().
 *
 *		Failure:	FAIL
 *
 * Programmer:	Quincey Koziol
 *		Tuesday, October 25, 2005
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Gget_create_plist(hid_t grp_id)
{
    H5VL_t     *vol_plugin;
    void       *grp;
    hid_t	ret_value = FAIL;

    FUNC_ENTER_API(FAIL)
    H5TRACE1("i", "i", grp_id);

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(grp_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
    /* get the dataset object */
    if(NULL == (grp = (void *)H5I_object(grp_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid group identifier")

    if(H5VL_group_get(grp, vol_plugin, H5VL_GROUP_GET_GCPL, H5_REQUEST_NULL, &ret_value) < 0)
        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group creation properties")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Gget_create_plist() */


/*-------------------------------------------------------------------------
 * Function:	H5Gget_info
 *
 * Purpose:	Retrieve information about a group.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		November 27 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Gget_info(hid_t loc_id, H5G_info_t *grp_info)
{
    H5VL_t     *vol_plugin;
    void       *obj;
    H5I_type_t  id_type;                /* Type of ID */
    H5VL_loc_params_t loc_params;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*x", loc_id, grp_info);

    /* Check args */
    id_type = H5I_get_type(loc_id);
    if(!(H5I_GROUP == id_type || H5I_FILE == id_type))
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid argument")
    if(!grp_info)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no info struct")

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
    /* get the dataset object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid group identifier")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = id_type;

    /* Get the group info through the VOL using the location token */
    if((ret_value = H5VL_group_get(obj, vol_plugin, H5VL_GROUP_GET_INFO, H5_REQUEST_NULL, 
                                   loc_params, grp_info)) < 0)
        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Gget_info() */


/*-------------------------------------------------------------------------
 * Function:	H5Gget_info_by_name
 *
 * Purpose:	Retrieve information about a group.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		November 27 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Gget_info_by_name(hid_t loc_id, const char *name, H5G_info_t *grp_info,
    hid_t lapl_id)
{
    H5VL_t     *vol_plugin;
    void       *obj;
    H5VL_loc_params_t loc_params;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE4("e", "i*s*xi", loc_id, name, grp_info, lapl_id);

    /* Check args */
    if(!name || !*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
    if(!grp_info)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no info struct")
    if(H5P_DEFAULT == lapl_id)
        lapl_id = H5P_LINK_ACCESS_DEFAULT;
    else
        if(TRUE != H5P_isa_class(lapl_id, H5P_LINK_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not link access property list ID")

    loc_params.type = H5VL_OBJECT_BY_NAME;
    loc_params.loc_data.loc_by_name.name = name;
    loc_params.loc_data.loc_by_name.plist_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
    /* get the dataset object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid group identifier")

    /* Get the group info through the VOL using the location token */
    if((ret_value = H5VL_group_get(obj, vol_plugin, H5VL_GROUP_GET_INFO, H5_REQUEST_NULL, 
                                   loc_params, grp_info)) < 0)
        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Gget_info_by_name() */


/*-------------------------------------------------------------------------
 * Function:	H5Gget_info_by_idx
 *
 * Purpose:	Retrieve information about a group, according to the order
 *              of an index.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		November 27 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Gget_info_by_idx(hid_t loc_id, const char *group_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t n, H5G_info_t *grp_info, hid_t lapl_id)
{
    H5VL_t     *vol_plugin;
    void       *obj;
    H5VL_loc_params_t loc_params;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE7("e", "i*sIiIoh*xi", loc_id, group_name, idx_type, order, n, grp_info,
             lapl_id);

    /* Check args */
    if(!group_name || !*group_name)
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
    if(!grp_info)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no info struct")
    if(H5P_DEFAULT == lapl_id)
        lapl_id = H5P_LINK_ACCESS_DEFAULT;
    else
        if(TRUE != H5P_isa_class(lapl_id, H5P_LINK_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not link access property list ID")

    loc_params.type = H5VL_OBJECT_BY_IDX;
    loc_params.loc_data.loc_by_idx.name = group_name;
    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
    loc_params.loc_data.loc_by_idx.order = order;
    loc_params.loc_data.loc_by_idx.n = n;
    loc_params.loc_data.loc_by_idx.plist_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the plugin pointer */
    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
    /* get the dataset object */
    if(NULL == (obj = (void *)H5I_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid group identifier")

    /* Get the group info through the VOL using the location token */
    if((ret_value = H5VL_group_get(obj, vol_plugin, H5VL_GROUP_GET_INFO, H5_REQUEST_NULL, 
                                   loc_params, grp_info)) < 0)
        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Gget_info_by_idx() */


/*-------------------------------------------------------------------------
 * Function:	H5Gclose
 *
 * Purpose:	Closes the specified group.  The group ID will no longer be
 *		valid for accessing the group.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Wednesday, December 31, 1997
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Gclose(hid_t group_id)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE1("e", "i", group_id);

    /* Check args */
    if(NULL == H5I_object_verify(group_id,H5I_GROUP))
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a group")

    /*
     * Decrement the counter on the group atom.	 It will be freed if the count
     * reaches zero.
     */
    if(H5I_dec_app_ref(group_id) < 0)
    	HGOTO_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "unable to close group")
#if 0
    /* Close the group through the VOL */
    if(H5VL_group_close(group_id, H5_REQUEST_NULL) < 0)
	HGOTO_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "unable to close group")
#endif

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Gclose() */


/*-------------------------------------------------------------------------
 * Function:	H5G_close_group
 *
 * Purpose:	Called when the ref count reaches zero on the group_id
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Mohamad Chaarawi
 *              June 2012
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5G_close_group(void *grp, H5VL_t *vol_plugin)
{
    herr_t              ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Close the group through the VOL*/
    if((ret_value = H5VL_group_close(grp, vol_plugin, H5_REQUEST_NULL)) < 0)
	HGOTO_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to close group")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5G_close_group() */