UnixCompress VB.NET Reference Documentation

UnixCompress

Current Version: 9.5.0.75

UNIX (.Z) compression component.

Object Creation

Dim obj As New Chilkat.UnixCompress()

Properties

AbortCurrent
AbortCurrent As Boolean
Introduced in version 9.5.0.58

When set to True, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to False when the next method is called. When the abort occurs, this property is reset to False. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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DebugLogFilePath
DebugLogFilePath As String

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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HeartbeatMs
HeartbeatMs As Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

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LastErrorHtml
LastErrorHtml As String (ReadOnly)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
LastErrorText As String (ReadOnly)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
LastErrorXml As String (ReadOnly)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
LastMethodSuccess As Boolean
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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VerboseLogging
VerboseLogging As Boolean

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Version As String (ReadOnly)

Version of the component/library, such as "9.5.0.63"

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Methods

CompressFile
Function CompressFile(ByVal inFilename As String, ByVal destPath As String) As Boolean

Compresses a file to create a UNIX compressed file (.Z). This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.

Returns True for success, False for failure.

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CompressFileAsync (1)
Function CompressFileAsync(ByVal inFilename As String, ByVal destPath As String) As Task

Creates an asynchronous task to call the CompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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CompressFileToMem
Function CompressFileToMem(ByVal inFilename As String) As Byte()

Unix compresses a file to an in-memory image of a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns an empty byte array on failure

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CompressFileToMemAsync (1)
Function CompressFileToMemAsync(ByVal inFilename As String) As Task

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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CompressMemory
Function CompressMemory(ByVal inData As Byte()) As Byte()

Compresses in-memory data to an in-memory image of a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns an empty byte array on failure

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CompressMemToFile
Function CompressMemToFile(ByVal inData As Byte(), ByVal destPath As String) As Boolean

Unix compresses and creates a .Z file from in-memory data. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns True for success, False for failure.

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CompressString
Function CompressString(ByVal inStr As String, ByVal charset As String) As Byte()

Compresses a string to an in-memory image of a .Z file. Prior to compression, the string is converted to the character encoding specified by charset. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns an empty byte array on failure

More Information and Examples
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CompressStringToFile
Function CompressStringToFile(ByVal inStr As String, ByVal charset As String, ByVal destPath As String) As Boolean

Unix compresses and creates a .Z file from string data. The charset specifies the character encoding used for the byte representation of the characters when compressed. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns True for success, False for failure.

More Information and Examples
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IsUnlocked
Function IsUnlocked() As Boolean

Returns true if the component has been unlocked. (For ActiveX, returns 1 if unlocked.)

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SaveLastError
Function SaveLastError(ByVal path As String) As Boolean

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns True for success, False for failure.

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UncompressFile
Function UncompressFile(ByVal inFilename As String, ByVal destPath As String) As Boolean

Uncompresses a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns True for success, False for failure.

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UncompressFileAsync (1)
Function UncompressFileAsync(ByVal inFilename As String, ByVal destPath As String) As Task

Creates an asynchronous task to call the UncompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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UncompressFileToMem
Function UncompressFileToMem(ByVal inFilename As String) As Byte()

Uncompresses a .Z file directly to memory. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns an empty byte array on failure

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UncompressFileToMemAsync (1)
Function UncompressFileToMemAsync(ByVal inFilename As String) As Task

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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UncompressFileToString
Function UncompressFileToString(ByVal zFilename As String, ByVal charset As String) As String

Uncompresses a .Z file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by charset. Typical charsets are "iso-8859-1", "utf-8", "windows-1252", "shift_JIS", "big5", etc.

Returns Nothing on failure

More Information and Examples
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UncompressFileToStringAsync (1)
Function UncompressFileToStringAsync(ByVal zFilename As String, ByVal charset As String) As Task

Creates an asynchronous task to call the UncompressFileToString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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UncompressMemory
Function UncompressMemory(ByVal inData As Byte()) As Byte()

Uncompresses from an in-memory image of a .Z file directly into memory. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns an empty byte array on failure

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UncompressMemToFile
Function UncompressMemToFile(ByVal inData As Byte(), ByVal destPath As String) As Boolean

Uncompresses from an in-memory image of a .Z file to a file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns True for success, False for failure.

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UncompressString
Function UncompressString(ByVal inCompressedData As Byte(), ByVal charset As String) As String

Uncompresses from an in-memory image of a .Z file directly to a string. The charset specifies the character encoding used to interpret the bytes resulting from the decompression. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns Nothing on failure

More Information and Examples
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UnlockComponent
Function UnlockComponent(ByVal unlockCode As String) As Boolean

Unlocks the component allowing for the full functionality to be used.

Returns True for success, False for failure.

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UnTarZ
Function UnTarZ(ByVal zFilename As String, ByVal destDir As String, ByVal bNoAbsolute As Boolean) As Boolean

Unpacks a .tar.Z file. The decompress and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring.

Returns True for success, False for failure.

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UnTarZAsync (1)
Function UnTarZAsync(ByVal zFilename As String, ByVal destDir As String, ByVal bNoAbsolute As Boolean) As Task

Creates an asynchronous task to call the UnTarZ method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

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Events

AbortCheck
Event OnAbortCheck

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

Args are passed using Chilkat.AbortCheckEventArgs

Event callback implementation:

Dim WithEvents unixcompress As Chilkat.UnixCompress

Private Sub unixcompress_OnAbortCheck(sender As Object, args As Chilkat.AbortCheckEventArgs) Handles unixcompress.OnAbortCheck

    ...

End Sub
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PercentDone
Event OnPercentDone

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to True will cause the method to abort and return a failed status (or whatever return value indicates failure).

Args are passed using Chilkat.PercentDoneEventArgs

Event callback implementation:

Dim WithEvents unixcompress As Chilkat.UnixCompress

Private Sub unixcompress_OnPercentDone(sender As Object, args As Chilkat.PercentDoneEventArgs) Handles unixcompress.OnPercentDone

    ...

End Sub
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ProgressInfo
Event OnProgressInfo

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

Args are passed using Chilkat.ProgressInfoEventArgs

Event callback implementation:

Dim WithEvents unixcompress As Chilkat.UnixCompress

Private Sub unixcompress_OnProgressInfo(sender As Object, args As Chilkat.ProgressInfoEventArgs) Handles unixcompress.OnProgressInfo

    ...

End Sub
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TaskCompleted
Event OnTaskCompleted

Called in the background thread when an asynchronous task completes.

More Information and Examples

Args are passed using Chilkat.TaskCompletedEventArgs

Event callback implementation:

Dim WithEvents unixcompress As Chilkat.UnixCompress

Private Sub unixcompress_OnTaskCompleted(sender As Object, args As Chilkat.TaskCompletedEventArgs) Handles unixcompress.OnTaskCompleted

    ...

End Sub
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