UnixCompress Xojo Plugin Reference Documentation

UnixCompress

Current Version: 10.0.0

Requires Chilkat Bundle License

UNIX (.Z) compression component.

Object Creation

Dim unixCompress 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.)

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:

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

More Information and Examples

Example showing how to use DebugLogFilePath.

HeartbeatMs

HeartbeatMs As Int32

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.

LastErrorHtml

LastErrorHtml As String (read-only)

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.

LastErrorText

LastErrorText As String (read-only)

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.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

LastErrorXml As String (read-only)

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.

LastMethodSuccess

LastMethodSuccess As Boolean

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.

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.

Version

Version As String (read-only)

Version of the component/library, such as "9.5.0.94"

More Information and Examples

How to get the Chilkat version at runtime.

Methods

CompressFile

Function CompressFile(inFilename As String, 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.

CompressFileAsync ⁽¹⁾

Function CompressFileAsync(inFilename As String, destPath As String) As Chilkat.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 Nil on failure

CompressFileToMem

Function CompressFileToMem(inFilename As String) As MemoryBlock

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

Returns Nil on failure

CompressFileToMemAsync ⁽¹⁾

Function CompressFileToMemAsync(inFilename As String) As Chilkat.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 Nil on failure

CompressMemory

Function CompressMemory(inData As MemoryBlock) As MemoryBlock

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

Returns Nil on failure

CompressMemToFile

Function CompressMemToFile(inData As MemoryBlock, 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.

CompressString

Function CompressString(inStr As String, charset As String) As MemoryBlock

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 Nil on failure

More Information and Examples

List of Valid Charsets

CompressStringToFile

Function CompressStringToFile(inStr As String, charset As String, 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

List of Valid Charsets

LoadTaskCaller

Function LoadTaskCaller(task As Chilkat.Task) As Boolean

Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

UncompressFile

Function UncompressFile(inFilename As String, 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.

UncompressFileAsync ⁽¹⁾

Function UncompressFileAsync(inFilename As String, destPath As String) As Chilkat.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 Nil on failure

UncompressFileToMem

Function UncompressFileToMem(inFilename As String) As MemoryBlock

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

Returns Nil on failure

UncompressFileToMemAsync ⁽¹⁾

Function UncompressFileToMemAsync(inFilename As String) As Chilkat.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 Nil on failure

UncompressFileToString

Function UncompressFileToString(zFilename As String, 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 Nil on failure

More Information and Examples

List of Valid Charsets

UncompressFileToStringAsync ⁽¹⁾

Function UncompressFileToStringAsync(zFilename As String, charset As String) As Chilkat.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 Nil on failure

UncompressMemory

Function UncompressMemory(inData As MemoryBlock) As MemoryBlock

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

Returns Nil on failure

UncompressMemToFile

Function UncompressMemToFile(inData As MemoryBlock, 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.

UncompressString

Function UncompressString(inCompressedData As MemoryBlock, 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 Nil on failure

More Information and Examples

List of Valid Charsets

UnTarZ

Function UnTarZ(zFilename As String, destDir As String, 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.

UnTarZAsync ⁽¹⁾

Function UnTarZAsync(zFilename As String, destDir As String, bNoAbsolute As Boolean) As Chilkat.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 Nil on failure

Events

To implement events, your application would define and implement a class that is a subclass of Chilkat.UnixCompress. Your custom class would implement (i.e. override) some or all of the event methods.

For example:

class MyUnixCompress
    Inherits Chilkat.UnixCompress

    Function AbortCheck() As Boolean

    Function PercentDone(pctDone As Int32) As Boolean

    Sub ProgressInfo(name As String, value As String)

    Sub TaskCompleted(task As Chilkat.Task)


End Class

AbortCheck

Function AbortCheck() As Boolean

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.

PercentDone

Function PercentDone(pctDone As Int32) As Boolean

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).

ProgressInfo

Sub ProgressInfo(name As String, value As String)

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.

TaskCompleted

Sub TaskCompleted(task As Chilkat.Task)

Called in the background thread when an asynchronous task completes.

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