HDF5 C++ API Reference Manual

 

 

H5::DataType Class Reference

#include <H5DataType.h>

Inheritance diagram for H5::DataType:

List of all members.

Public Member Functions
	DataType (const H5T_class_t type_class, size_t size)
	Creates a object given its class and size.
	DataType (const DataType &original)
	Copy constructor: makes a copy of the original DataType object.
	DataType (H5Object &obj, const void *ref, H5R_type_t ref_type=H5R_OBJECT)
	Given a reference, ref, to an hdf5 group, creates a DataType object.
	DataType (H5File &h5file, const void *ref, H5R_type_t ref_type=H5R_OBJECT)
	Given a reference, ref, to an hdf5 group, creates a DataType object.
	DataType (Attribute &attr, const void *ref, H5R_type_t ref_type=H5R_OBJECT)
	Given a reference, ref, to an hdf5 group, creates a DataType object.
virtual void	close ()
	Closes the datatype if it is not a predefined type.
void	copy (const DataType &like_type)
	Copies an existing datatype to this datatype object.
void	copy (const DataSet &dset)
	Copies the datatype of the given dataset to this datatype object.
H5T_class_t	getClass () const
	Returns the datatype class identifier.
void	commit (H5File &loc, const char *name)
	Commits a transient datatype to a file, creating a new named datatype.
void	commit (H5File &loc, const H5std_string &name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.
void	commit (H5Object &loc, const char *name)
	Commits a transient datatype to a file, creating a new named datatype.
void	commit (H5Object &loc, const H5std_string &name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.
bool	committed () const
	Determines whether a datatype is a named type or a transient type.
H5T_conv_t	find (const DataType &dest, H5T_cdata_t **pcdata) const
	Finds a conversion function that can handle a conversion from this datatype to the specified datatype, dest.
void	convert (const DataType &dest, size_t nelmts, void *buf, void *background, const PropList &plist=PropList::DEFAULT) const
	Converts data from this datatype to the specified datatypes.
DataType &	operator= (const DataType &rhs)
	Assignment operator.
bool	operator== (const DataType &compared_type) const
	Compares this DataType against the given one to determines whether the two objects refer to the same actual datatype.
void	lock () const
	Locks a datatype, making it read-only and non-destructible.
size_t	getSize () const
	Returns the size of a datatype.
DataType	getSuper () const
	Returns the base datatype from which a datatype is derived.
void	registerFunc (H5T_pers_t pers, const char *name, const DataType &dest, H5T_conv_t func) const
	Registers the specified conversion function.
void	registerFunc (H5T_pers_t pers, const H5std_string &name, const DataType &dest, H5T_conv_t func) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.
void	unregister (H5T_pers_t pers, const char *name, const DataType &dest, H5T_conv_t func) const
	Removes a conversion function from all conversion paths.
void	unregister (H5T_pers_t pers, const H5std_string &name, const DataType &dest, H5T_conv_t func) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.
void	setTag (const char *tag) const
	Tags an opaque datatype.
void	setTag (const H5std_string &tag) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.
H5std_string	getTag () const
	Gets the tag associated with an opaque datatype.
bool	detectClass (H5T_class_t cls) const
	Checks whether a datatype contains (or is) a certain type of datatype.
bool	isVariableStr () const
	Check whether this datatype is a variable-length string.
H5G_obj_t	getObjType (void *ref, H5R_type_t ref_type=H5R_OBJECT) const
	Retrieves the type of object that an object reference points to.
DataSpace	getRegion (void *ref, H5R_type_t ref_type=H5R_DATASET_REGION) const
	Retrieves a dataspace with the region pointed to selected.
virtual H5std_string	fromClass () const
	Returns this class name.
	DataType (const hid_t type_id)
	Creates a datatype using an existing datatype's id.
	DataType ()
	Default constructor: Creates a stub datatype.
virtual hid_t	getId () const
virtual	~DataType ()
	Properly terminates access to this datatype.
Protected Member Functions
virtual void	p_setId (const hid_t new_id)
	Sets the identifier of this object to a new value.
Protected Attributes
hid_t	id

---

Constructor & Destructor Documentation

H5::DataType::DataType	(	const H5T_class_t	type_class,
		size_t	size
	)

Creates a object given its class and size.

Parameters:

	type_class	- IN: Class of datatype to create
	size	- IN: Number of bytes in the datatype to create

Exceptions:

H5::DataTypeIException

H5::DataType::DataType

(

const DataType &

original

)

Copy constructor: makes a copy of the original DataType object.

H5::DataType::DataType	(	H5Object &	obj,
		const void *	ref,
		H5R_type_t	ref_type = H5R_OBJECT
	)

Given a reference, ref, to an hdf5 group, creates a DataType object.

Parameters:

	obj	- IN: Specifying location referenced object is in
	ref	- IN: Reference pointer
	ref_type	- IN: Reference type - default to H5R_OBJECT

Exceptions:

H5::ReferenceException

Description

obj can be DataSet, Group, or named DataType, that is a datatype that has been named by DataType::commit.

H5::DataType::DataType	(	H5File &	h5file,
		const void *	ref,
		H5R_type_t	ref_type = H5R_OBJECT
	)

Given a reference, ref, to an hdf5 group, creates a DataType object.

Parameters:

	h5file	- IN: Location referenced object is in
	ref	- IN: Reference pointer
	ref_type	- IN: Reference type - default to H5R_OBJECT

Exceptions:

H5::ReferenceException

H5::DataType::DataType	(	Attribute &	attr,
		const void *	ref,
		H5R_type_t	ref_type = H5R_OBJECT
	)

Given a reference, ref, to an hdf5 group, creates a DataType object.

Parameters:

	attr	- IN: Specifying location where the referenced object is in
	ref	- IN: Reference pointer
	ref_type	- IN: Reference type - default to H5R_OBJECT

Exceptions:

H5::ReferenceException

H5::DataType::DataType

(

const hid_t

existing_id

)

Creates a datatype using an existing datatype's id.

Parameters:

existing_id

- IN: Id of the existing datatype

H5::DataType::DataType

(

)

Default constructor: Creates a stub datatype.

H5::DataType::~DataType

(

)

[virtual]

Properly terminates access to this datatype.

---

Member Function Documentation

void H5::DataType::close

(

)

[virtual]

Closes the datatype if it is not a predefined type.

Exceptions:

H5::DataTypeIException

void H5::DataType::copy

(

const DataType &

like_type

)

Copies an existing datatype to this datatype object.

Parameters:

like_type

- IN: Datatype to be copied

Exceptions:

H5::DataTypeIException

void H5::DataType::copy

(

const DataSet &

dset

)

Copies the datatype of the given dataset to this datatype object.

Description

The resulted dataset will be transient and modifiable.

H5T_class_t H5::DataType::getClass

(

)

const

Returns the datatype class identifier.

Returns:

Datatype class identifier

Exceptions:

H5::DataTypeIException

void H5::DataType::commit	(	H5File &	loc,
		const char *	name
	)

Commits a transient datatype to a file, creating a new named datatype.

Parameters:

	loc	- IN: A file
	name	- IN: Name of the datatype

Exceptions:

H5::DataTypeIException

void H5::DataType::commit	(	H5File &	loc,
		const H5std_string &	name
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.

void H5::DataType::commit	(	H5Object &	loc,
		const char *	name
	)

Commits a transient datatype to a file, creating a new named datatype.

Parameters:

	loc	- IN: Either a group, dataset, named datatype, or attribute.
	name	- IN: Name of the datatype

Exceptions:

H5::DataTypeIException

void H5::DataType::commit	(	H5Object &	loc,
		const H5std_string &	name
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.

bool H5::DataType::committed

(

)

const

Determines whether a datatype is a named type or a transient type.

Returns:

true if the datatype is a named type, and false, otherwise.

Exceptions:

H5::DataTypeIException

H5T_conv_t H5::DataType::find	(	const DataType &	dest,
		H5T_cdata_t **	pcdata
	)			const

Finds a conversion function that can handle a conversion from this datatype to the specified datatype, dest.

Parameters:

	dest	- IN: Destination datatype
	pcdata	- IN: Pointer to type conversion data

Returns:

Pointer to a suitable conversion function

Exceptions:

H5::DataTypeIException

void H5::DataType::convert	(	const DataType &	dest,
		size_t	nelmts,
		void *	buf,
		void *	background,
		const PropList &	plist = PropList::DEFAULT
	)			const

Converts data from this datatype to the specified datatypes.

Parameters:

	dest	- IN: Destination datatype
	nelmts	- IN: Size of array buf
	buf	- IN/OUT: Array containing pre- and post-conversion values
	background	- IN: Optional backgroud buffer
	plist	- IN: Dataset transfer property list

Returns:

Pointer to a suitable conversion function

Exceptions:

H5::DataTypeIException

DataType & H5::DataType::operator=

(

const DataType &

rhs

)

Assignment operator.

Parameters:

rhs

- IN: Reference to the existing datatype

Returns:

Reference to DataType instance

Exceptions:

H5::DataTypeIException

bool H5::DataType::operator==

(

const DataType &

compared_type

)

const

Compares this DataType against the given one to determines whether the two objects refer to the same actual datatype.

Parameters:

compared_type

- IN: Reference to the datatype to compare

Returns:

true if the datatypes are equal, and false, otherwise.

Exceptions:

H5::DataTypeIException

void H5::DataType::lock

(

)

const

Locks a datatype, making it read-only and non-destructible.

Exceptions:

H5::DataTypeIException

Descrition

This is normally done by the library for predefined data types so the application doesn't inadvertently change or delete a predefined type.

Once a data type is locked it can never be unlocked unless the entire library is closed.

size_t H5::DataType::getSize

(

)

const

Returns the size of a datatype.

Returns:

Datatype size in bytes

Exceptions:

H5::DataTypeIException

Examples:

readdata.cpp.

DataType H5::DataType::getSuper

(

)

const

Returns the base datatype from which a datatype is derived.

Returns:

DataType object

Exceptions:

H5::DataTypeIException

void H5::DataType::registerFunc	(	H5T_pers_t	pers,
		const char *	name,
		const DataType &	dest,
		H5T_conv_t	func
	)			const

Registers the specified conversion function.

Parameters:

	pers	- IN: Conversion option H5T_PERS_HARD for hard conversion functions H5T_PERS_SOFT for soft conversion functions.
	name	- IN: Name displayed in diagnostic output.
	dest	- IN: Destination datatype.
	func	- IN: Function to convert between source and destination datatypes.

Exceptions:

H5::DataTypeIException

Description

For more information, please see: http://www.hdfgroup.org/HDF5/doc/RM/RM_H5T.html#Datatype-Register

void H5::DataType::registerFunc	(	H5T_pers_t	pers,
		const H5std_string &	name,
		const DataType &	dest,
		H5T_conv_t	func
	)			const

This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.

void H5::DataType::unregister	(	H5T_pers_t	pers,
		const char *	name,
		const DataType &	dest,
		H5T_conv_t	func
	)			const

Removes a conversion function from all conversion paths.

Parameters:

	pers	- IN: Conversion option H5T_PERS_HARD for hard conversion functions H5T_PERS_SOFT for soft conversion functions.
	name	- IN: Name displayed in diagnostic output.
	dest	- IN: Destination datatype.
	func	- IN: Function to convert between source and destination datatypes.

Exceptions:

H5::DataTypeIException

void H5::DataType::unregister	(	H5T_pers_t	pers,
		const H5std_string &	name,
		const DataType &	dest,
		H5T_conv_t	func
	)			const

This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.

void H5::DataType::setTag

(

const char *

tag

)

const

Tags an opaque datatype.

Parameters:

tag

- IN: Descriptive ASCII string with which the opaque datatype is to be tagged.

Exceptions:

H5::DataTypeIException

void H5::DataType::setTag

(

const H5std_string &

tag

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in the type of the argument name.

H5std_string H5::DataType::getTag

(

)

const

Gets the tag associated with an opaque datatype.

Returns:

Tag associated with the opaque datatype

Exceptions:

H5::DataTypeIException

bool H5::DataType::detectClass

(

H5T_class_t

cls

)

const

Checks whether a datatype contains (or is) a certain type of datatype.

Returns:

true if this datatype contains or is the specified type, and false, otherwise.

Exceptions:

H5::DataTypeIException

bool H5::DataType::isVariableStr

(

)

const

Check whether this datatype is a variable-length string.

Returns:

true if this datatype is a variable-length string, and false, otherwise.

Exceptions:

H5::DataTypeIException

H5G_obj_t H5::DataType::getObjType	(	void *	ref,
		H5R_type_t	ref_type = H5R_OBJECT
	)			const

Retrieves the type of object that an object reference points to.

Parameters:

	ref	- IN: Reference to query
	ref_type	- IN: Type of reference to query

Returns:

Object type, which can be one of the following:

• H5G_LINK Object is a symbolic link.
• H5G_GROUP Object is a group.
• H5G_DATASET Object is a dataset.
• H5G_TYPE Object is a named datatype

Exceptions:

H5::DataTypeIException

DataSpace H5::DataType::getRegion	(	void *	ref,
		H5R_type_t	ref_type = H5R_DATASET_REGION
	)			const

Retrieves a dataspace with the region pointed to selected.

Parameters:

	ref	- IN: Reference to get region of
	ref_type	- IN: Type of reference to get region of - default

Returns:

DataSpace instance

Exceptions:

H5::DataTypeIException

virtual H5std_string H5::DataType::fromClass

(

)

const [inline, virtual]

Returns this class name.

Reimplemented in H5::ArrayType, H5::AtomType, H5::CompType, H5::EnumType, H5::FloatType, H5::IntType, H5::PredType, H5::StrType, and H5::VarLenType.

hid_t H5::DataType::getId

(

)

const [virtual]

Implements H5::IdComponent.

void H5::DataType::p_setId

(

const hid_t

new_id

)

[protected, virtual]

Sets the identifier of this object to a new value.

Exceptions:

H5::IdComponentException

when the attempt to close the HDF5 object fails

---

Member Data Documentation

hid_t H5::DataType::id [protected]

---