Gzip Xojo Plugin Reference Documentation

Gzip

Current Version: 9.5.0.73

GZip compression component.

Object Creation

Dim gzip As New Chilkat.Gzip

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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Comment
Comment As String

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

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CompressionLevel
CompressionLevel As Int32
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.

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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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ExtraData
ExtraData As MemoryBlock

Optional extra-data that can be included within a .gz when a Compress* method is called.

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Filename
Filename As String

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.

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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.

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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.

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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.

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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.

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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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LastModStr
LastModStr As String

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

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UseCurrentDate
UseCurrentDate As Boolean

If set to True, 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.

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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 (read-only)

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

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Methods

CompressBd
Function CompressBd(binDat As Chilkat.BinData) As Boolean
Introduced in version 9.5.0.67

In-place gzip the contents of binDat.

Returns True for success, False for failure.

More Information and Examples
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CompressBdAsync (1)
Function CompressBdAsync(binDat As Chilkat.BinData) As Chilkat.Task
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.)

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

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

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

Returns True for success, False for failure.

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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

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CompressFile2
Function CompressFile2(inFilename As String, embeddedFilename As String, destPath As String) 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 True for success, False for failure.

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CompressFile2Async (1)
Function CompressFile2Async(inFilename As String, embeddedFilename As String, destPath As String) As Chilkat.Task

Creates an asynchronous task to call the CompressFile2 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

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CompressFileToMem
Function CompressFileToMem(inFilename As String) As MemoryBlock

Gzip compresses a file to an in-memory image of a .gz file.

Returns Nil on failure

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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

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CompressMemory
Function CompressMemory(inData As MemoryBlock) As MemoryBlock

Compresses in-memory data to an in-memory image of a .gz file.

Returns Nil on failure

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CompressMemoryAsync (1)
Function CompressMemoryAsync(inData As MemoryBlock) As Chilkat.Task

Creates an asynchronous task to call the CompressMemory 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

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CompressMemToFile
Function CompressMemToFile(inData As MemoryBlock, destPath As String) As Boolean

Gzip compresses and creates a .gz file from in-memory data.

Returns True for success, False for failure.

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CompressMemToFileAsync (1)
Function CompressMemToFileAsync(inData As MemoryBlock, destPath As String) As Chilkat.Task

Creates an asynchronous task to call the CompressMemToFile 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

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

Gzip compresses a string and writes the output to a byte array. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.

Returns Nil on failure

More Information and Examples
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CompressStringAsync (1)
Function CompressStringAsync(inStr As String, destCharset As String) As Chilkat.Task

Creates an asynchronous task to call the CompressString 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

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CompressStringENC
Function CompressStringENC(inStr As String, charset As String, encoding As String) As String

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 Nil on failure

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CompressStringToFile
Function CompressStringToFile(inStr As String, destCharset As String, destPath As String) 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 True for success, False for failure.

More Information and Examples
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CompressStringToFileAsync (1)
Function CompressStringToFileAsync(inStr As String, destCharset As String, destPath As String) As Chilkat.Task

Creates an asynchronous task to call the CompressStringToFile 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

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Decode
Function Decode(encodedStr As String, encoding As String) As MemoryBlock

Decodes an encoded string and returns the original data. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns Nil on failure

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DeflateStringENC
Function DeflateStringENC(inString As String, charsetName As String, outputEncoding As String) As String

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 Nil on failure

More Information and Examples
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Encode
Function Encode(byteData As MemoryBlock, encoding As String) As String

Encodes binary data to a printable string. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns Nil on failure

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ExamineFile
Function ExamineFile(inGzFilename As String) As Boolean

Determines if the inGzFilename is a Gzip formatted file. Returns True if it is a Gzip formatted file, otherwise returns False.

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ExamineMemory
Function ExamineMemory(inGzData As MemoryBlock) As Boolean

Determines if the in-memory bytes (inGzData) contain a Gzip formatted file. Returns True if it is Gzip format, otherwise returns False.

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GetDt
Function GetDt() As Chilkat.CkDateTime

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

Returns Nil on failure

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InflateStringENC
Function InflateStringENC(inString As String, convertFromCharset As String, inputEncoding As String) As String

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 Nil on failure

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IsUnlocked
Function IsUnlocked() As Boolean

Returns True if the component has been unlocked.

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ReadFile
Function ReadFile(path As String) As MemoryBlock

Reads a binary file into memory and returns the byte array. Note: This method does not parse a Gzip, it is only a convenience method for reading a binary file into memory.

Returns Nil on failure

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SaveLastError
Function SaveLastError(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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SetDt
Function SetDt(dt As Chilkat.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 True for success, False for failure.

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UncompressBd
Function UncompressBd(binDat As Chilkat.BinData) As Boolean
Introduced in version 9.5.0.67

In-place ungzip the contents of binDat.

Returns True for success, False for failure.

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UncompressBdAsync (1)
Function UncompressBdAsync(binDat As Chilkat.BinData) As Chilkat.Task
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.)

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

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UncompressFile
Function UncompressFile(srcPath As String, destPath As String) 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 True for success, False for failure.

More Information and Examples
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UncompressFileAsync (1)
Function UncompressFileAsync(srcPath 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

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UncompressFileToMem
Function UncompressFileToMem(inFilename As String) As MemoryBlock

Un-Gzips a .gz file directly to memory.

Returns Nil on failure

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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

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UncompressFileToString
Function UncompressFileToString(gzFilename As String, charset As String) As String

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 Nil on failure

More Information and Examples
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UncompressFileToStringAsync (1)
Function UncompressFileToStringAsync(gzFilename 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

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UncompressMemory
Function UncompressMemory(inData As MemoryBlock) As MemoryBlock

Un-Gzips from an in-memory image of a .gz file directly into memory.

Returns Nil on failure

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UncompressMemoryAsync (1)
Function UncompressMemoryAsync(inData As MemoryBlock) As Chilkat.Task

Creates an asynchronous task to call the UncompressMemory 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

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UncompressMemToFile
Function UncompressMemToFile(inData As MemoryBlock, destPath As String) As Boolean

Un-Gzips from an in-memory image of a .gz file to a file.

Returns True for success, False for failure.

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UncompressMemToFileAsync (1)
Function UncompressMemToFileAsync(inData As MemoryBlock, destPath As String) As Chilkat.Task

Creates an asynchronous task to call the UncompressMemToFile 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

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UncompressString
Function UncompressString(inData As MemoryBlock, inCharset As String) As String

The reverse of CompressString.

The bytes in inData are uncompressed, then converted from inCharset (if necessary) to return a string.

Returns Nil on failure

More Information and Examples
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UncompressStringAsync (1)
Function UncompressStringAsync(inData As MemoryBlock, inCharset As String) As Chilkat.Task

Creates an asynchronous task to call the UncompressString 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

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UncompressStringENC
Function UncompressStringENC(inStr As String, charset As String, encoding As String) As String

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 Nil on failure

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UnlockComponent
Function UnlockComponent(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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UnTarGz
Function UnTarGz(tgzFilename As String, destDir As String, 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 True or False. A value of True protects from untarring to absolute paths. (For example, imagine the trouble if the tar contains files with absolute paths beginning with /Windows/system32)

Returns True for success, False for failure.

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UnTarGzAsync (1)
Function UnTarGzAsync(tgzFilename As String, destDir As String, bNoAbsolute As Boolean) As Chilkat.Task

Creates an asynchronous task to call the UnTarGz 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

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WriteFile
Function WriteFile(path As String, binaryData As MemoryBlock) As Boolean

A convenience method for writing a binary byte array to a file.

Returns True for success, False for failure.

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XfdlToXml
Function XfdlToXml(xfldData As String) As String

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 Nil on failure

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Events

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

For example:

class MyGzip
    Inherits Chilkat.Gzip

    Function AbortCheck() As Boolean

    Sub BinaryData(data As MemoryBlock)

    Function PercentDone(pctDone As Int32) As Boolean

    Sub ProgressInfo(name As String, value As String)

    Sub TaskCompleted(task As Chilkat.Task)

    Sub TextData(data As String)


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.

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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).

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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.

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TaskCompleted
Sub TaskCompleted(task As Chilkat.Task)

Called in the background thread when an asynchronous task completes.

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