ObjectHeaderMessageType

Full name Microsoft.VisualBasic.Data.IO.HDF5.struct.ObjectHeaderMessageType Assembly Microsoft.VisualBasic.Data.IO.HDF5 Members 33

Disk Format: Level 2A2 - Data Object Header Messages

Data object header messages are small pieces of metadata that are stored in the data object header for each object in an HDF5 file. Data object header messages provide the metadata required to describe an object and its contents, as well as optional pieces of metadata that annotate the meaning or purpose of the object.

Data object header messages are either stored directly in the data object header for the object Or are shared between multiple objects in the file. When a message Is shared, a flag in the Message Flags indicates that the actual Message Data portion of that message Is stored in another location (such as another data object header, Or a heap in the file) And the Message Data field contains the information needed to locate the actual information for the message.

01 Syntax

Microsoft.VisualBasic.Data.IO.HDF5.struct.ObjectHeaderMessageType

02 Methods

Name	Overloads	Summary
GetType	2	Get the MessageType by number.
ToString	1	Message name.

03 Properties

Name	Overloads	Summary
num	1	Message number.
type	1

04 Fields

Name	Overloads	Summary
NIL	2	The NIL message is used to indicate a message which is to be ignored when reading the header messages for a data object.
SimpleDataspace	2	The dataspace message describes the number of dimensions (in other words, "rank") and size of each dimension that the data object has.
GroupNew	2
FillValueOld	2	The fill value message stores a single data value which is returned to the application when an uninitialized data element is read from a dataset.
Link	2	This message encodes the information for a link in a group's object header, when the group is storing its links “compactly”, or in the group’s fractal heap, when the group is sto…
ObjectHeaderContinuation	2	The Object Header Continuation Message The object header continuation is the location in the file of a block containing more header messages for the current data object.
Group	2	Each "old style" group has a v1 B-tree and a local heap for storing symbol table entries, which are located with this message.
Datatype	1
FillValue	1
ExternalDataFiles	1
Layout	1
GroupInfo	1
FilterPipeline	1
Attribute	1
Comment	1
LastModifiedOld	1
SharedObject	1
Bogus	1
LastModified	1
AttributeInfo	1
ObjectReferenceCount	1

05 Members

method GetType overload 2 #

GetType(String)

Find the MessageType that matches this name.

Parameters

Name	Type	Description
`name`	`String`	find DataTYpe with this name.

Returns

DataType or null if no match.

method GetType #

GetType(Int32)

Get the MessageType by number.

Parameters

Name	Type	Description
`num`	`Int32`	message number.

Returns

the MessageType

method ToString #

ToString

Message name.

property num #

num

Message number.

field NIL #

NIL

The NIL message is used to indicate a message which is to be ignored when reading the header messages for a data object. [Possibly one which has been deleted for some reason.]

field SimpleDataspace #

SimpleDataspace

The dataspace message describes the number of dimensions (in other words, "rank") and size of each dimension that the data object has. This message is only used for datasets which have a simple, rectilinear, array-like layout; datasets requiring a more complex layout are not yet supported.

field GroupNew #

GroupNew

field FillValueOld #

FillValueOld

The fill value message stores a single data value which is returned to the application when an uninitialized data element is read from a dataset. The fill value is interpreted with the same datatype as the dataset. If no fill value message is present then a fill value of all zero bytes is assumed.

This fill value message Is deprecated In favor Of the “new” fill value message (Message Type 0x0005) And Is only written To the file For forward compatibility With versions Of the HDF5 Library before the 1.6.0 version. Additionally, it only appears For datasets With a user-defined fill value (As opposed To the library Default fill value Or an explicitly Set “undefined” fill value).

field Link #

Link

This message encodes the information for a link in a group's object header, when the group is storing its links “compactly”, or in the group’s fractal heap, when the group is storing its links “densely”.

A group Is storing its links compactly When the fractal heap address In the Link Info Message Is Set To the “undefined address” value.

field ObjectHeaderContinuation #

ObjectHeaderContinuation

The Object Header Continuation Message

The object header continuation is the location in the file of a block containing more header messages for the current data object. This can be used when header blocks become too large or are likely to change over time.

field Group #

Group

Each "old style" group has a v1 B-tree and a local heap for storing symbol table entries, which are located with this message.

field NIL overload 2 #

NIL

field SimpleDataspace overload 2 #

SimpleDataspace

field GroupNew overload 2 #

GroupNew

field Datatype #

Datatype

field FillValueOld overload 2 #

FillValueOld

field FillValue #

FillValue

field Link overload 2 #

Link

field ExternalDataFiles #

ExternalDataFiles

field Layout #

Layout

field GroupInfo #

GroupInfo

field FilterPipeline #

FilterPipeline

field Attribute #

Attribute

field Comment #

Comment

field LastModifiedOld #

LastModifiedOld

field SharedObject #

SharedObject

field ObjectHeaderContinuation overload 2 #

ObjectHeaderContinuation

field Bogus #

Bogus

field Group overload 2 #

Group

field LastModified #

LastModified

field AttributeInfo #

AttributeInfo

field ObjectReferenceCount #

ObjectReferenceCount

property type #

type