Gzip Lianja Reference Documentation
Gzip
Current Version: 10.1.2
GZip compression component.
Object Creation
loObject = createobject("CkGzip")
Properties
AbortCurrent
When set to .T., 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 .F. when the next method is called. When the abort occurs, this property is reset to .F.. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)
topComment
Specifies an optional comment string that can be embedded within the .gz when any Compress* method is called.
topCompressionLevel
The compression level to be used when compressing. The default is 6, which is the typical value used for zip utility programs when compressing data. The compression level may range from 0 (no compression) to 9 (the most compression). The benefits of trying to increase compression may not be worth the added expense in compression time. In many cases (which is data dependent), the improvement in compression is minimal while the increase in computation time is significant.
topDebugLogFilePath
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.
Filename
The filename that is embedded within the .gz during any Compress* method call. When extracting from a .gz using applications such as WinZip, this will be the filename that is created.
topLastErrorHtml
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: .T. means success, .F. 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.
topLastModStr
The same as the LastMod property, but allows the date/time to be get/set in RFC822 string format.
topUseCurrentDate
If set to .T., the file produced by an Uncompress* method will use the current date/time for the last-modification date instead of the date/time found within the Gzip format.
topVerboseLogging
If set to .T., then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is .F.. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
topVersion
Methods
CompressBd
In-place gzip the contents of binDat.
Returns .T. for success, .F. for failure.
CompressBdAsync (1)
Creates an asynchronous task to call the CompressBd method with the arguments provided.
Returns .F. on failure
topCompressFile
Compresses a file to create a GZip compressed file (.gz).
Returns .T. for success, .F. for failure.
CompressFileAsync (1)
Creates an asynchronous task to call the CompressFile method with the arguments provided.
Returns .F. on failure
topCompressFile2
Compresses a file to create a GZip compressed file (.gz). inFilename is the actual filename on disk. embeddedFilename is the filename to be embedded in the .gz such that when it is un-gzipped, this is the name of the file that will be created.
Returns .T. for success, .F. for failure.
CompressFile2Async (1)
Creates an asynchronous task to call the CompressFile2 method with the arguments provided.
Returns .F. on failure
topCompressStringENC
The same as CompressString, except the binary output is returned in encoded string form according to the encoding. The encoding can be any of the following: "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".
Returns .F. on failure
topCompressStringToFile
Gzip compresses a string and writes the output to a .gz compressed file. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.
Returns .T. for success, .F. for failure.
CompressStringToFileAsync (1)
Creates an asynchronous task to call the CompressStringToFile method with the arguments provided.
Returns .F. on failure
topDeflateStringENC
Provides the ability to use the zip/gzip's deflate algorithm directly to compress a string. Internal to this method, inString is first converted to the charset specified by charsetName. The data is then compressed using the deflate compression algorithm. The binary output is then encoded according to outputEncoding. Possible values for outputEncoding are "hex", "base64", "url", and "quoted-printable".
Note: The output of this method is compressed data with no Gzip file format. Use the Compress* methods to produce Gzip file format output.
Returns .F. on failure
ExamineFile
Determines if the inGzFilename is a Gzip formatted file. Returns .T. if it is a Gzip formatted file, otherwise returns .F..
topGetDt
InflateStringENC
This the reverse of DeflateStringENC.
The input string is first decoded according to inputEncoding. (Possible values for inputEncoding are "hex", "base64", "url", and "quoted-printable".) The compressed data is then inflated, and the result is then converted from convertFromCharset (if necessary) to return a string.
Returns .F. on failure
topLoadTaskCaller
SetDt
Sets the last-modification date/time to be embedded within the .gz when a Compress* method is called. If not explicitly set, the current system date/time is used.
Returns .T. for success, .F. for failure.
topUncompressBd
UncompressBdAsync (1)
Creates an asynchronous task to call the UncompressBd method with the arguments provided.
Returns .F. on failure
topUncompressFile
Un-Gzips a .gz file. The output filename is specified by the 2nd argument and not by the filename embedded within the .gz.
Returns .T. for success, .F. for failure.
UncompressFileAsync (1)
Creates an asynchronous task to call the UncompressFile method with the arguments provided.
Returns .F. on failure
topUncompressFileToString
Uncompresses a .gz 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 .F. on failure
UncompressFileToStringAsync (1)
Creates an asynchronous task to call the UncompressFileToString method with the arguments provided.
Returns .F. on failure
topUncompressStringENC
The same as UncompressString, except the compressed data is provided in encoded string form based on the value of encoding. The encoding can be "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".
Returns .F. on failure
topUnTarGz
Unpacks a .tar.gz file. The ungzip and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring. bNoAbsolute may be .T. or .F.. A value of .T. protects from untarring to absolute paths. (For example, imagine the trouble if the tar contains files with absolute paths beginning with /Windows/system32)
Returns .T. for success, .F. for failure.
topUnTarGzAsync (1)
Creates an asynchronous task to call the UnTarGz method with the arguments provided.
Returns .F. on failure
topXfdlToXml
Converts base64-gzip .xfdl data to a decompressed XML string. The xfldData contains the base64 data. This method returns the decoded/decompressed XML string.
Returns .F. on failure
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