UnixCompress Xbase++ Reference Documentation
UnixCompress
Current Version: 11.6.0
Chilkat.UnixCompress
Compress files, memory data, or strings into UNIX
Expand UNIX-compressed data back to files, memory, byte arrays, or text
depending on the application workflow.
Compress and uncompress directly between input and output files when
working with existing filesystem data.
Work with compressed or uncompressed byte data in memory when temporary
files are not desired.
Compress and uncompress text using an explicit character set so string
data round-trips correctly.
Use
For an extended overview, see
UnixCompress Class Overview.
Compress, uncompress, and unpack legacy UNIX
.Z files.Chilkat.UnixCompress provides UNIX compress and
uncompress functionality for legacy .Z files. It
supports file-based, memory-based, and string-based workflows, uses LZW
compression, can unpack .tar.Z archives, and includes abort and
progress-related support for longer-running operations.
Compress to .Z
.Z
format using LZW compression.
Uncompress .Z data
File workflows
Memory workflows
String workflows
Unpack tar.Z archives
UnTarZ to decompress and extract legacy
.tar.Z archives in a single workflow.
UnixCompress when the data is in classic UNIX
.Z format or when a .tar.Z archive must be
unpacked. Use Chilkat.Gzip for .gz and
.tar.gz files, Chilkat.Bz2 for
.bz2 files, and Chilkat.Compression for raw
compression algorithms and general-purpose compression workflows.
Object Creation
LOCAL oUnixCompress
oUnixCompress := CreateObject("Chilkat.UnixCompress")
// ... use oUnixCompress ...
oUnixCompress:destroy()Xbase++ uses the Chilkat ActiveX through the automation object returned by CreateObject(); properties and methods are accessed with the send operator (oHttp:ConnectTimeout := 30, oHttp:Download(cUrl, cPath)), and :destroy() releases the object. Register the Chilkat ActiveX matching the bitness of your Xbase++ application. To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as CreateObject("Chilkat.UnixCompress.11") for Chilkat v11.*.*.
Boolean properties, arguments and return values are integers in the ActiveX: pass 1 or 0, and test a method's success with == 1. A method that fails to return an object returns NIL. Objects returned by methods (such as an HttpResponse or JsonObject) are automation objects too and should likewise be released with :destroy(). Methods and properties that pass or return raw byte arrays are not shown on this page; use the BinData-based alternatives (methods ending in Bd) or the base64 / hex string-encoded variants instead.
Properties
AbortCurrent
When set to 1, 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 0 when the next method is called. When the abort occurs, this property is reset to 0. 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
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
LastStringResult
In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topVerboseLogging
If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
Methods
CompressFile
Compresses a file to create a UNIX compressed file (.Z). This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.
Returns 1 for success, 0 for failure.
topCompressFileAsync (1)
Creates an asynchronous task to call the CompressFile method with the arguments provided.
Returns NIL on failure
CompressStringToFile
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 1 for success, 0 for failure.
LoadTaskCaller
UncompressFile
Uncompresses a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)
Returns 1 for success, 0 for failure.
topUncompressFileAsync (1)
Creates an asynchronous task to call the UncompressFile method with the arguments provided.
Returns NIL on failure
UncompressFileToString
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
UncompressFileToStringAsync (1)
Creates an asynchronous task to call the UncompressFileToString method with the arguments provided.
Returns NIL on failure
UnTarZ
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 1 for success, 0 for failure.
topUnTarZAsync (1)
Creates an asynchronous task to call the UnTarZ method with the arguments provided.
Returns NIL on failure