h5das.cc File Reference

Data attributes processing source. More...

#include "hdf5_handler.h"

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Functions
void	add_group_structure_info (DAS &das, const char *gname, char *oname, bool is_group)
	will insert group information in a structure format into DAS table. More...
void	depth_first (hid_t pid, const char *gname, DAS &das)
	depth first traversal of hdf5 file attributes. More...
void	find_gloattr (hid_t file, DAS &das)
	will fill in attributes of the root group into one DAS table. More...
string	get_hardlink (hid_t pgroup, const string &oname)
	will put hardlink information into a DAS table. More...
void	get_softlink (DAS &das, hid_t pgroup, const char *gname, const string &oname, int index, size_t val_size)
string	print_attr (hid_t type, int loc, void *sm_buf)
	will get the printed representation of an attribute. More...
void	read_comments (DAS &das, const string &varname, hid_t oid)
	will fill in attributes of a group's comment into DAS table. More...
void	read_objects (DAS &das, const string &varname, hid_t oid, int num_attr)
	will fill in attributes of a dataset or a group into one DAS table. More...

Variables
HDF5PathFinder	paths
	A variable for remembering visited paths to break cyclic HDF5 groups. More...

Detailed Description

Data attributes processing source.

This file is part of h5_dap_handler, a C++ implementation of the DAP handler for HDF5 data.

This is the HDF5-DAS that extracts DAS class descriptors converted from HDF5 attribute of an hdf5 data file.

Author

Hyo-Kyung Lee hyokl.nosp@m.ee@h.nosp@m.dfgro.nosp@m.up.o.nosp@m.rg

Muqun Yang myang.nosp@m.6@hd.nosp@m.fgrou.nosp@m.p.or.nosp@m.g

Definition in file h5das.cc.

Function Documentation

add_group_structure_info	(	DAS &	das,
		const char *	gname,
		char *	oname,
		bool	is_group
	)

will insert group information in a structure format into DAS table.

This function adds a special attribute called "HDF5_ROOT_GROUP" if the gname is "/". If is_group is true, it keeps appending new attribute table called oname under the gname path. If is_group is false, it appends a string attribute called oname. For details, see the HDF5-DAP2 Mapping Technical Note from [1].

[1] http://www.hdfgroup.org/projects/opendap/opendap_docs.html

Parameters

das	DAS object: reference
gname	absolute group pathname of an object
oname	name of object
is_group	indicates whether it's a dataset or group

Returns

nothing

Definition at line 916 of file h5das.cc.

References NULL.

Referenced by depth_first().

depth_first	(	hid_t	pid,
		const char *	gname,
		DAS &	das
	)

depth first traversal of hdf5 file attributes.

This function will walk through an hdf5 group using depth- first approach to obtain all the group and dataset attributes of an hdf5 file. During the process of the depth first search, DAS table will be filled. In case of errors, an exception will be thrown.

Parameters

pid	dataset id(group id)
gname	group name(absolute name from the root group)
das	reference of DAS object

Returns

void

To keep track of soft links.

Definition at line 60 of file h5das.cc.

References add_group_structure_info(), depth_first(), DODS_NAMELEN, get_hardlink(), HDF5PathFinder::get_name(), get_softlink(), NULL, read_comments(), and read_objects().

Referenced by depth_first(), HDF5RequestHandler::hdf5_build_das(), HDF5RequestHandler::hdf5_build_data(), and HDF5RequestHandler::hdf5_build_dds().

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find_gloattr	(	hid_t	file,
		DAS &	das
	)

will fill in attributes of the root group into one DAS table.

The attributes are treated as global attributes.

Parameters

das	DAS object reference
file	HDF5 file id

Exceptions

msg	string of error message to the dods interface.

Returns

void

Definition at line 683 of file h5das.cc.

References get_hardlink(), and read_objects().

Referenced by HDF5RequestHandler::hdf5_build_das(), HDF5RequestHandler::hdf5_build_data(), and HDF5RequestHandler::hdf5_build_dds().

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get_hardlink	(	hid_t	pgroup,
		const string &	oname
	)

will put hardlink information into a DAS table.

Parameters

pgroup	object id
oname	object name: absolute name of a group

Returns

true if succeeded.

false if failed.

Remarks

In case of error, it returns a string of error message to the DAP interface.

Warning

This is only a test, not supported in current version.

Definition at line 824 of file h5das.cc.

References HDF5PathFinder::add().

Referenced by depth_first(), and find_gloattr().

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void get_softlink	(	DAS &	das,
		hid_t	pgroup,
		const char *	gname,
		const string &	oname,
		int	index,
		size_t	val_size
	)

Definition at line 765 of file h5das.cc.

Referenced by depth_first().

print_attr	(	hid_t	type,
		int	loc,
		void *	sm_buf
	)

will get the printed representation of an attribute.

This function is based on netcdf-dods server.

Parameters

type	HDF5 data type id
loc	the number of array number
sm_buf	pointer to an attribute

Returns

a char * to newly allocated memory, the caller must call delete []

Todo:

This probably needs to be re-considered!

Due to the priority of the handler work, this function will not be

re-written in this re-engineering process. KY 2011-Nov. 14th

Definition at line 288 of file h5das.cc.

References NULL.

Referenced by nc_read_dataset_attributes(), and read_objects().

read_comments	(	DAS &	das,
		const string &	varname,
		hid_t	oid
	)

will fill in attributes of a group's comment into DAS table.

Parameters

das	DAS object: reference
varname	absolute name of an object
oid	object id

Returns

nothing

Definition at line 868 of file h5das.cc.

References comment, and NULL.

Referenced by depth_first().

void read_objects	(	DAS &	das,
		const string &	varname,
		hid_t	oid,
		int	num_attr
	)

will fill in attributes of a dataset or a group into one DAS table.

Parameters

das	DAS object: reference
varname	absolute name of an HDF5 dataset or an HDF5 group
oid	HDF5 object id(a handle)
num_attr	number of attributes.

Returns

nothing

See also

get_attr_info(hid_t dset, int index, DSattr_t * attr_inst_ptr,int *ignoreptr, char *error)

get_dap_type()

Definition at line 481 of file h5das.cc.

References get_attr_info(), get_dap_type(), HDF5_OBJ_FULLPATH, DSattr::name, DSattr::ndims, DSattr::need, DSattr::nelmts, NULL, print_attr(), and DSattr::type.

Referenced by depth_first(), and find_gloattr().

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Variable Documentation

HDF5PathFinder paths

A variable for remembering visited paths to break cyclic HDF5 groups.

Definition at line 42 of file h5das.cc.