Gzip Lianja Reference Documentation

Gzip

GZip compression component.

Object Creation

loObject = createobject("CkGzip")

Properties

AbortCurrent As Boolean

Introduced in version 9.5.0.58

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.)

Comment As Character

Specifies an optional comment string that can be embedded within the .gz when any Compress* method is called.

CompressionLevel As Numeric

Introduced in version 9.5.0.50

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.

DebugLogFilePath As Character

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.

Filename As Character

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.

LastErrorHtml As Character (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 As Character (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.

Concept of LastErrorText

LastErrorText Standard Information

LastErrorXml As Character (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 As Boolean

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of .T. indicates success, a value of .F. 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 = .T. and failure = .F..
  • 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 .T.. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

LastModStr As Character

The same as the LastMod property, but allows the date/time to be get/set in RFC822 string format.

UseCurrentDate As Boolean

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.

VerboseLogging As Boolean

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.

Version As Character (read-only)

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

Methods

CompressBd(binDat As CkBinData) As Boolean

Introduced in version 9.5.0.67

In-place gzip the contents of binDat.

Returns .T. for success, .F. for failure.

Gzip Compress In Memory and Base64 Encode

CompressBdAsync(binDat As CkBinData) As CkTask

Introduced in version 9.5.0.67

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

Returns .F. on failure

How to Run an Asynchronous Task

CompressFile(inFilename As Character, destPath As Character) As Boolean

Compresses a file to create a GZip compressed file (.gz).

Returns .T. for success, .F. for failure.

CompressFileAsync(inFilename As Character, destPath As Character) As CkTask

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

Returns .F. on failure

How to Run an Asynchronous Task

CompressFile2(inFilename As Character, embeddedFilename As Character, destPath As Character) As Boolean

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(inFilename As Character, embeddedFilename As Character, destPath As Character) As CkTask

Creates an asynchronous task to call the CompressFile2 method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns .F. on failure

How to Run an Asynchronous Task

CompressStringENC(inStr As Character, charset As Character, encoding As Character) As Character

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

CompressStringToFile(inStr As Character, destCharset As Character, destPath As Character) As Boolean

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.

Full List of Charset Names

CompressStringToFileAsync(inStr As Character, destCharset As Character, destPath As Character) As CkTask

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

Returns .F. on failure

How to Run an Asynchronous Task

DeflateStringENC(inString As Character, charsetName As Character, outputEncoding As Character) As Character

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

Full List of Charset Names

ExamineFile(inGzFilename As Character) As Boolean

Determines if the inGzFilename is a Gzip formatted file. Returns .T. if it is a Gzip formatted file, otherwise returns .F..

GetDt() As CkDateTime

Gets the last-modification date/time to be embedded within the .gz.

Returns .F. on failure

InflateStringENC(inString As Character, convertFromCharset As Character, inputEncoding As Character) As Character

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

IsUnlocked() As Boolean

Returns .T. if the component has been unlocked.

SaveLastError(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

SetDt(dt As CkDateTime) As Boolean

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.

UncompressBd(binDat As CkBinData) As Boolean

Introduced in version 9.5.0.67

In-place ungzip the contents of binDat.

Returns .T. for success, .F. for failure.

UncompressBdAsync(binDat As CkBinData) As CkTask

Introduced in version 9.5.0.67

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

Returns .F. on failure

How to Run an Asynchronous Task

UncompressFile(srcPath As Character, destPath As Character) As Boolean

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.

GZip Decompress File

UncompressFileAsync(srcPath As Character, destPath As Character) As CkTask

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

Returns .F. on failure

How to Run an Asynchronous Task

UncompressFileToString(gzFilename As Character, charset As Character) As Character

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

List of Valid Charsets

UncompressFileToStringAsync(gzFilename As Character, charset As Character) As CkTask

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

Returns .F. on failure

How to Run an Asynchronous Task

UncompressStringENC(inStr As Character, charset As Character, encoding As Character) As Character

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

UnlockComponent(unlockCode As Character) As Boolean

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

Returns .T. for success, .F. for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Purchased Unlock Code

LastErrorText Standard Information

UnTarGz(tgzFilename As Character, destDir As Character, bNoAbsolute As Boolean) As Boolean

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.

UnTarGzAsync(tgzFilename As Character, destDir As Character, bNoAbsolute As Boolean) As CkTask

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

Returns .F. on failure

How to Run an Asynchronous Task

XfdlToXml(xfldData As Character) As Character

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