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IPWorks ZIP 2022 .NET Edition

Version 22.0 [Build 8214]

Gzip Component

Properties   Methods   Events   Configuration Settings   Errors  

The Gzip component implements a gzip compressor and decompressor. It is compliant with RFC 1952 and compatible with the UNIX gzip and gunzip utilities.

Syntax

nsoftware.IPWorksZip.Gzip

Remarks

The gzip file format is typically used only to archive a single file. Accordingly, the operation of the component is simpler than that of the other components.

To compress with the component, set ArchiveFile to the name of the gzip file to be created, and FileDecompressedName to the name of the file to be compressed. Finally, invoke Compress. To extract the file, first set ArchiveFile. FileDecompressedName may then be set; if not, it will automatically be set from the gzip file headers. Finally, invoke the Extract or Compress method.

.tar.gz files may be created or extracted in one step by using the Tar component. See the documentation for Tar for more details.

Example (Creating a Gzip File)

ZipControl.ArchiveFile = "c:\test.gz" ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Compress() Example (Extracting from a Gzip File)

ZipControl.ArchiveFile = "c:\test.gz" ZipControl.Scan() ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Extract()

Property List


The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

ArchiveFileThe name of the zip, gzip, tar, or jar archive.
CompressionLevelThe compression level to use.
CompressionMethodThe compression method for the component to use.
ExtractToPathA base path to decompress to.
FileCompressedDateThe date and time of the compressed file, as stored within the gzip archive.
FileCompressedNameFilename, as stored inside of the archive.
FileDecompressedNameFile name to decompress to, or compress from.
FileDecompressedSizeGets the size of the file, as decompressed outside the archive.
FileInputDataThe data of the file to be compressed.
GzipData(Decompression only) The gzip file contents as a byte array.
HasMoreDataShows whether or not there is more data in the gzip archive.

Method List


The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

AbortAborts the current operation.
AppendAdds specified file to an existing archive.
CompressCreates the compressed gzip archive.
ConfigSets or retrieves a configuration setting.
ExtractExtracts the compressed file from the gzip archive.
ExtractAllExtracts all files from the compressed archive.
ResetResets the component.
ScanScans the compressed archive.
SetArchiveInputStreamThe stream to read the zip, tar, jar, or gzip archive from.
SetArchiveOutputStreamThe stream to write the zip, tar, jar, or gzip archive to.
SetFileInputStreamThe input stream to read the decompressed data from.

Event List


The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

BeginFileFired before a file is processed.
EndFileFired after a file is processed.
ErrorInformation about non-fatal errors.
OverwriteFired whenever a file exists and may be overwritten.
ProgressFired as progress is made.

Configuration Settings


The following is a list of configuration settings for the component with short descriptions. Click on the links for further details.

CloseStreamAfterCompressIf true, the component will close the output stream after compression.
FileCommentHolds the comment associated with the archive.
PreserveModifiedTimeWhether or not to preserve the original modified time on extracted files.
WriteToProgressEventWhether or not to write data to the Progress Event.
BuildInfoInformation about the product's build.
GUIAvailableTells the component whether or not a message loop is available for processing events.
LicenseInfoInformation about the current license.
UseInternalSecurityAPITells the component whether or not to use the system security libraries or an internal implementation.

ArchiveFile Property (Gzip Component)

The name of the zip, gzip, tar, or jar archive.

Syntax

public string ArchiveFile { get; set; }
Public Property ArchiveFile As String

Default Value

""

Remarks

This property specifies the name of the archive to be read or written. This property is required when extracting files.

When Scan, Extract, or ExtractAll is invoked, the file specified by ArchiveFile will be opened for read. If the file does not exist, a trappable error will be generated.

When Compress is called, the file named by ArchiveFile will be written; if a file of this name already exists the Overwrite event will be fired. If ArchiveFile is set to the empty string (""), the archive will not be written to disk, and will be provided only through the Progress event.

The filename may be specified with or without a path. Paths may be relative or absolute, and should be specified in the format native to the host operating system. The filename should be specified with the appropriate extension (such as "zip"); an extension will not automatically be appended by the component.

If the file cannot be read, or written, as appropriate, a trappable error will be generated.

Example (Creating an Archive)

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.RecurseSubdirectories = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress()

Note: an archive already open for read may be closed by setting ArchiveFile to the empty string ("").

CompressionLevel Property (Gzip Component)

The compression level to use.

Syntax

public int CompressionLevel { get; set; }
Public Property CompressionLevel As Integer

Default Value

4

Remarks

This property specifies the level of compression to be used, between 1 and 6. Higher values will cause the component to compress better; lower values will cause the component to compress faster.

Storing without compression is not supported for Gzip.

CompressionMethod Property (Gzip Component)

The compression method for the component to use.

Syntax

public GzipCompressionMethods CompressionMethod { get; set; }

enum GzipCompressionMethods { cmgDeflate, cmgLZCCompress }
Public Property CompressionMethod As GzipCompressionMethods

Enum GzipCompressionMethods cmgDeflate cmgLZCCompress End Enum

Default Value

0

Remarks

By default, the component uses the Deflate compression method described in rfc 1952. When set to LZC compress method, the component will use a variation of the method described by the LZW (Lempel-Ziv-Welch) algorithm that is compatible with Unix's compress utility.

ExtractToPath Property (Gzip Component)

A base path to decompress to.

Syntax

public string ExtractToPath { get; set; }
Public Property ExtractToPath As String

Default Value

""

Remarks

Setting the ExtractToPath property affects the operation of the Extract and ExtractAll methods. Setting this property to a nonempty string will cause all decompressed files to be written to the specified path. If pathnames are given in the values of FileDecompressedName they will be regarded as relative to ExtractToPath.

If the specified directory does not exist, it will be created when extraction is done.

ExtractToPath should always be specified in the format native to the host operating system, and with a trailing slash or backslash. If the path is specified otherwise, it will be immediately converted and stored in the converted format. For example, "/temp" would be immediately converted to "\temp\" on a Windows system.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

FileCompressedDate Property (Gzip Component)

The date and time of the compressed file, as stored within the gzip archive.

Syntax

public long FileCompressedDate { get; }
Public ReadOnly Property FileCompressedDate As Long

Default Value

0

Remarks

FileCompressedDate contains the last modified date of the file, as stored within the archive (it does not generally correspond to when the file was compressed).

FileCompressedDate is returned in a platform-specific format. The Java and other editions will return the number of milliseconds since January 1, 1970, 00:00:00. This value may be passed directly to the java.util.Date constructor to create a java.util.Date object representing this date.

The .NET Edition will return the number of ticks, or 100-nanosecond intervals, since January 1, 0001, 00:00:00. This value may be passed directly to the System.DateTime constructor to create a System.DateTime object representing this date.

Reading the value of this property will return a meaningful value only after a call to Scan or Extract. If a meaningful value is not available this property will return a value of 0.

This property is read-only and not available at design time.

FileCompressedName Property (Gzip Component)

Filename, as stored inside of the archive.

Syntax

public string FileCompressedName { get; set; }
Public Property FileCompressedName As String

Default Value

""

Remarks

FileCompressedName contains the name of the compressed file, as stored within the gzip header.

This field should generally be set with a relative path or with no path at all. The exact interpretation of the path is left to the decompression software; generally, pathnames will be interpreted as relative to a base directory, and these subdirectories will be created as needed. Absolute pathnames will not be interpreted correctly by the component, and may or may not be interpreted correctly by other decompression software.

Paths should be specified in standard (UNIX) format. They may also be specified in the format native to the host operating system, in which case they will be immediately converted.

It is not usually necessary to manually set the value of this property; it will be assigned by Compress if it is not specified, and it will always be written by a call to Scan or Extract.

FileDecompressedName Property (Gzip Component)

File name to decompress to, or compress from.

Syntax

public string FileDecompressedName { get; set; }
Public Property FileDecompressedName As String

Default Value

""

Remarks

FileDecompressedName contains the name of the file in the archive, as stored on the file system, outside the archive.

When compressing a file, this property should be specified with a path, if necessary, to allow the file to be found by the component. If the file cannot be found when Compress is called, a trappable error will be generated, and the archive will not be correctly written.

When decompressing files, this property may be set after calling Scan and prior to calling Extract. If this property is set to the empty string when Extract is called, Extract will automatically set this property to an appropriate value.

Note: If Scan is not called before Extract, the component will internally call the method and any value in FileDecompressedName will be overwritten.

Paths on the local file system should be specified in the format native to the host operating system. They may also be specified in standard (UNIX) format, in which case they will be immediately converted.

FileDecompressedSize Property (Gzip Component)

Gets the size of the file, as decompressed outside the archive.

Syntax

public long FileDecompressedSize { get; }
Public ReadOnly Property FileDecompressedSize As Long

Default Value

-1

Remarks

This property holds the decompressed size of the file. If an archive is open for read (i.e. has been scanned or decompressed), this information will be read from the archive headers. If an archive is not open for read, the component will retrieve the information for the corresponding value of DecompressedName from the local file system.

A value of -1 will be returned in case of an I/O error.

This property is read-only and not available at design time.

FileInputData Property (Gzip Component)

The data of the file to be compressed.

Syntax

public string FileInputData { get; set; }
public byte[] FileInputDataB { get; set; }
Public Property FileInputData As String
Public Property FileInputDataB As Byte()

Default Value

""

Remarks

When this property is set, the component will read in the data from this property instead of reading from the file contained in the FileDecompressedName property.

This property is not available at design time.

GzipData Property (Gzip Component)

(Decompression only) The gzip file contents as a byte array.

Syntax

public string GzipData { set; }
public byte[] GzipDataB { set; }
Public WriteOnly Property GzipData As String
Public WriteOnly Property GzipDataB As Byte()

Default Value

""

Remarks

Normally you should set ArchiveFile before invoking Scan or Extract. If you prefer to read the gzip file from memory you may set GzipData instead. GzipData should be set to the entire contents of the gzip file; this will allow you to read from the archive without writing any temporary files to disk.

If you would like to extract data from the archive without ever writing to disk you should also set WriteToProgressEvent to true, and after invoking Scan, you should set the value of FileDecompressedName to an empty string. Then, when you invoke Extract (or ExtractAll) the data will be provided in the Progress event.

This property is write-only. Note that modifying a gzip file stored in GzipData is not supported, so Append will throw exceptions.

This property is write-only and not available at design time.

HasMoreData Property (Gzip Component)

Shows whether or not there is more data in the gzip archive.

Syntax

public bool HasMoreData { get; }
Public ReadOnly Property HasMoreData As Boolean

Default Value

False

Remarks

The Gzip format described in RFC 1952 allows multiple gzipped data members to be concatenated into a single file. However, due to the nature of the algorithm it is impossible to determine the number of data members until after the entire archive has been decompressed. The HasMoreData property can be used to cycle through the archive and extract each file.

Simply set the ArchiveFile and ExtractToPath properties, then call Extract as long as the component has available data.

Note: the component will not update FileDecompressedName unless you call Scan or manually set FileDecompressedName on each loop before calling Extract.

Example (Extracting Multiple Files)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" Do ZipControl.Scan() //here you may inspect the file name in FileDecompressedName prior to extraction ZipControl.Extract() While ZipControl.HasMoreData

This property is read-only.

Abort Method (Gzip Component)

Aborts the current operation.

Syntax

public void Abort();

Async Version
public async Task Abort();
public async Task Abort(CancellationToken cancellationToken);
Public Sub Abort()

Async Version
Public Sub Abort() As Task
Public Sub Abort(cancellationToken As CancellationToken) As Task

Remarks

Abort may be used to immediately interrupt compression or decompression. Any files partially written by the component will be deleted.

Append Method (Gzip Component)

Adds specified file to an existing archive.

Syntax

public void Append();

Async Version
public async Task Append();
public async Task Append(CancellationToken cancellationToken);
Public Sub Append()

Async Version
Public Sub Append() As Task
Public Sub Append(cancellationToken As CancellationToken) As Task

Remarks

The file contained in the FileDecompressedName property will be appended to the archive specified by ArchiveFile.

This method may only be used to add files to an existing archive. To add files to a new archive, Compress method should be used.

Compress Method (Gzip Component)

Creates the compressed gzip archive.

Syntax

public void Compress();

Async Version
public async Task Compress();
public async Task Compress(CancellationToken cancellationToken);
Public Sub Compress()

Async Version
Public Sub Compress() As Task
Public Sub Compress(cancellationToken As CancellationToken) As Task

Remarks

Invoking Compress creates the archive specified by ArchiveFile. When the method is called, the file specified by FileDecompressedName will be opened, and the file specified by ArchiveFile will contain the compressed output.

The filename to be stored within the archive is given by FileCompressedName. If this property is set to the empty string, it will be set to an appropriate value automatically; the component always writes a filename in the gzip headers.

As the data is compressed the Progress event will be fired at regular intervals. This event may be used to stream out the gzip file, or to display a progress bar to the user.

Config Method (Gzip Component)

Sets or retrieves a configuration setting.

Syntax

public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Extract Method (Gzip Component)

Extracts the compressed file from the gzip archive.

Syntax

public void Extract();

Async Version
public async Task Extract();
public async Task Extract(CancellationToken cancellationToken);
Public Sub Extract()

Async Version
Public Sub Extract() As Task
Public Sub Extract(cancellationToken As CancellationToken) As Task

Remarks

Invoking Extract decompresses the archive specified by ArchiveFile. The compressed file will be extracted, and written to disk. Also, FileCompressedName will be set to the filename found in the archive.

If FileDecompressedName is set to a nonempty string the file will be written there. Otherwise the component will automatically set FileDecompressedName to an appropriate value:

If a filename (i.e., FileCompressedName) is stored in the gzip headers, this filename will be used.

Otherwise, if ArchiveFile ends in ".gz", this filename, less the ".gz" extension will be used. If there are multiple files in the archive, the current 0-based file index will be appended to all files after the first file to differentiate between multiple files. For instance "test.gz" would become "test" for the first file and "test.gz" would become "test.1" for the second file in the archive.

If neither of these two conditions holds, ".unzipped" will be appended to ArchiveFile.

ExtractAll Method (Gzip Component)

Extracts all files from the compressed archive.

Syntax

public void ExtractAll();

Async Version
public async Task ExtractAll();
public async Task ExtractAll(CancellationToken cancellationToken);
Public Sub ExtractAll()

Async Version
Public Sub ExtractAll() As Task
Public Sub ExtractAll(cancellationToken As CancellationToken) As Task

Remarks

ExtractAll extracts all files from the archive. The file(s) will be extracted to the directory specified by ExtractToPath, and given the names found in the archive or specified by FileDecompressedName.

If Scan has not been invoked when ExtractAll is called, Scan will automatically be invoked, and the FileCompressedName and FileDecompressedName properties will be set to the values found in the archive. To manually set the decompressed filenames, Scan should be invoked before setting FileDecompressedName.

The BeginFile and EndFile events will be fired before and after each file is extracted, and the Progress event will be fired as the data is extracted. If WriteToProgressEvent is set to true, the decompressed data will be streamed out through the Progress event.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

Reset Method (Gzip Component)

Resets the component.

Syntax

public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

Reset resets the state of the component. All properties will be set to their default values, and any files open will be closed.

Scan Method (Gzip Component)

Scans the compressed archive.

Syntax

public void Scan();

Async Version
public async Task Scan();
public async Task Scan(CancellationToken cancellationToken);
Public Sub Scan()

Async Version
Public Sub Scan() As Task
Public Sub Scan(cancellationToken As CancellationToken) As Task

Remarks

This method will scan the gzip archive specified by ArchiveFile. The archive will be read, the header will be checked, and the stored filename will be written to FileCompressedName.

Unlike in the Zip, Tar, and Jar components, it is never necessary to invoke this method, and it will not be automatically invoked by Extract. Suggested uses for this method would be to check that the file is a gzip file, or to determine an appropriate value for FileDecompressedName.

SetArchiveInputStream Method (Gzip Component)

The stream to read the zip, tar, jar, or gzip archive from.

Syntax

public void SetArchiveInputStream(System.IO.Stream archiveStream);

Async Version
public async Task SetArchiveInputStream(System.IO.Stream archiveStream);
public async Task SetArchiveInputStream(System.IO.Stream archiveStream, CancellationToken cancellationToken);
Public Sub SetArchiveInputStream(ByVal ArchiveStream As System.IO.Stream)

Async Version
Public Sub SetArchiveInputStream(ByVal ArchiveStream As System.IO.Stream) As Task
Public Sub SetArchiveInputStream(ByVal ArchiveStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

Remarks

This method should be set when the archive is to be read from a stream when Extract is called.

By default, and when this is set to null, the component will read from the file specified by ArchiveFile. However, when this is a valid stream, the data will be read from the stream.

SetArchiveOutputStream Method (Gzip Component)

The stream to write the zip, tar, jar, or gzip archive to.

Syntax

public void SetArchiveOutputStream(System.IO.Stream archiveStream);

Async Version
public async Task SetArchiveOutputStream(System.IO.Stream archiveStream);
public async Task SetArchiveOutputStream(System.IO.Stream archiveStream, CancellationToken cancellationToken);
Public Sub SetArchiveOutputStream(ByVal ArchiveStream As System.IO.Stream)

Async Version
Public Sub SetArchiveOutputStream(ByVal ArchiveStream As System.IO.Stream) As Task
Public Sub SetArchiveOutputStream(ByVal ArchiveStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

Remarks

This method should be set when the archive is to be written to a stream when Compress is called.

By default, and when this is set to null, the component will write to the file specified by ArchiveFile. However, when this is a valid stream, the data will be written to the stream.

SetFileInputStream Method (Gzip Component)

The input stream to read the decompressed data from.

Syntax

public void SetFileInputStream(System.IO.Stream archiveStream);

Async Version
public async Task SetFileInputStream(System.IO.Stream archiveStream);
public async Task SetFileInputStream(System.IO.Stream archiveStream, CancellationToken cancellationToken);
Public Sub SetFileInputStream(ByVal ArchiveStream As System.IO.Stream)

Async Version
Public Sub SetFileInputStream(ByVal ArchiveStream As System.IO.Stream) As Task
Public Sub SetFileInputStream(ByVal ArchiveStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

Remarks

When this method is set to a valid stream, the component will read in the data from the stream as the current file instead of reading from the file contained in the FileDecompressedName property.

BeginFile Event (Gzip Component)

Fired before a file is processed.

Syntax

public event OnBeginFileHandler OnBeginFile;

public delegate void OnBeginFileHandler(object sender, GzipBeginFileEventArgs e);

public class GzipBeginFileEventArgs : EventArgs {
  public int Index { get; }
  public bool Skip { get; set; }
}
Public Event OnBeginFile As OnBeginFileHandler

Public Delegate Sub OnBeginFileHandler(sender As Object, e As GzipBeginFileEventArgs)

Public Class GzipBeginFileEventArgs Inherits EventArgs
  Public ReadOnly Property Index As Integer

  Public Property Skip As Boolean

End Class

Remarks

BeginFile is fired before compression or decompression begins. Index will contain 0.

You may use the Skip parameter to tell the component to skip the file when appending or decompressing.

EndFile Event (Gzip Component)

Fired after a file is processed.

Syntax

public event OnEndFileHandler OnEndFile;

public delegate void OnEndFileHandler(object sender, GzipEndFileEventArgs e);

public class GzipEndFileEventArgs : EventArgs {
  public int Index { get; }
}
Public Event OnEndFile As OnEndFileHandler

Public Delegate Sub OnEndFileHandler(sender As Object, e As GzipEndFileEventArgs)

Public Class GzipEndFileEventArgs Inherits EventArgs
  Public ReadOnly Property Index As Integer

End Class

Remarks

EndFile is fired when compression or decompression finishes. Index will contain 0.

Error Event (Gzip Component)

Information about non-fatal errors.

Syntax

public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, GzipErrorEventArgs e);

public class GzipErrorEventArgs : EventArgs {
  public string Description { get; }
  public int ErrorCode { get; }
  public int Index { get; }
  public string Filename { get; }
  public bool Ignore { get; set; }
}
Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As GzipErrorEventArgs)

Public Class GzipErrorEventArgs Inherits EventArgs
  Public ReadOnly Property Description As String

  Public ReadOnly Property ErrorCode As Integer

  Public ReadOnly Property Index As Integer

  Public ReadOnly Property Filename As String

  Public Property Ignore As Boolean

End Class

Remarks

The Error event is fired when non-fatal errors occur during compression or decompression. Note that if this event is fired during decompression this may indicate that the archive is corrupt.

By default these errors will cause the component to fail with an exception. The exception may be overridden by setting Ignore to true. This will cause the error to be ignored, the file will be skipped if necessary, and the component will continue operation.

ErrorCode will correspond to one of the following errors:

1Bad or missing CRC-32 checksum.
2Failed to set creation date of a file.
111Can't open file for read (skipping).

Description contains a textual description of the error. Index and Filename contain the array index (where appropriate) and filename of the file being processed at the time of the error.

Overwrite Event (Gzip Component)

Fired whenever a file exists and may be overwritten.

Syntax

public event OnOverwriteHandler OnOverwrite;

public delegate void OnOverwriteHandler(object sender, GzipOverwriteEventArgs e);

public class GzipOverwriteEventArgs : EventArgs {
  public string Filename { get; set; }
  public bool Overwrite { get; set; }
}
Public Event OnOverwrite As OnOverwriteHandler

Public Delegate Sub OnOverwriteHandler(sender As Object, e As GzipOverwriteEventArgs)

Public Class GzipOverwriteEventArgs Inherits EventArgs
  Public Property Filename As String

  Public Property Overwrite As Boolean

End Class

Remarks

Overwrite is fired when a file is about to be overwritten, and would overwrite an existing file. The event is fired during decompression.

Filename contains the full name of the file, specified with its pathname.

Overwrite specifies whether or not the file will be overwritten. For Zip, Jar, and Tar, this is equal by default to the value of the OverwriteFiles property. For Gzip, this value defaults to true.

Either of the parameters may be changed when the event is fired. Changing the value of Overwrite will override the default behavior of the component, and cause the file to be overwritten or not overwritten, depending on the value set. If Filename is changed, the value of Overwrite will be ignored, and the file will be written with the specified name. If a file of the new name also exists this file will be silently overwritten.

Progress Event (Gzip Component)

Fired as progress is made.

Syntax

public event OnProgressHandler OnProgress;

public delegate void OnProgressHandler(object sender, GzipProgressEventArgs e);

public class GzipProgressEventArgs : EventArgs {
  public string Data { get; }
public byte[] DataB { get; } public string Filename { get; } public long BytesProcessed { get; } public int PercentProcessed { get; } }
Public Event OnProgress As OnProgressHandler

Public Delegate Sub OnProgressHandler(sender As Object, e As GzipProgressEventArgs)

Public Class GzipProgressEventArgs Inherits EventArgs
  Public ReadOnly Property Data As String
Public ReadOnly Property DataB As Byte() Public ReadOnly Property Filename As String Public ReadOnly Property BytesProcessed As Long Public ReadOnly Property PercentProcessed As Integer End Class

Remarks

The Progress event is automatically fired as compression or decompression is performed. When WriteToProgressEvent is true, the output data is provided through the Data parameter, allowing for it to be streamed out.

Filename contains the name of the file being written. If no file is being written, Filename will contain an empty string, and the output data will be provided exclusively through this event.

BytesProcessed contains the total number of uncompressed bytes processed. PercentProcessed contains the percent of uncompressed bytes processed, corresponding roughly to the running time of the operation.

For Gzip extraction only, BytesProcessed and PercentProcessed will reflect the number of compressed bytes extracted, as it is generally impossible to predetermine the total uncompressed size.

If WriteToProgressEvent is false, Data will contain null.

Configuration Settings (Gzip Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

Gzip Configuration Settings

CloseStreamAfterCompress:   If true, the component will close the output stream after compression.

This property is true by default. Therefore, by default, the output stream will be closed after compression is completed. In order to keep streams open after the compression completes, you must set this config to false.

FileComment:   Holds the comment associated with the archive.

When compressing this may be set to include a comment in the archive. This will also hold the comment associated with an archive after calling Scan.

PreserveModifiedTime:   Whether or not to preserve the original modified time on extracted files.

Specifies whether or not the modified time of the extracted files use the current time or the original time of the file in the archive.

When set to True (default) the extracted files will have the same modified time as the original file.

When set to False the modified time on the extracted files will be set to the current time.

WriteToProgressEvent:   Whether or not to write data to the Progress Event.

If WriteToProgressEvent is set to true, then all data produced through invocations of Extract, ExtractAll, and Compress will be written to the Progress event as well as to disk. Applications may stream out the compressed or decompressed data by trapping this event and copying the data.

If WriteToProgressEvent is set to false, the data will not be streamed out, and the Data parameter of the Progress event will contain null.

By default, this config is set to false.

Base Configuration Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

GUIAvailable:   Tells the component whether or not a message loop is available for processing events.

In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the component does not attempt to process external events.

LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
UseInternalSecurityAPI:   Tells the component whether or not to use the system security libraries or an internal implementation.

By default the component will use the system security libraries to perform cryptographic functions where applicable. When set to false calls to unmanaged code will be made. In certain environments this is not desirable. To use a completely managed security implementation set this setting to true. Setting this to true tells the component to use the internal implementation instead of using the system's security API.

Note: This setting is static. The value set is applicable to all components used in the application.

When this value is set the product's system DLL is no longer required as a reference, as all unmanaged code is stored in that file.

Trappable Errors (Gzip Component)

Errors

The following errors may be generated by the component. Note that frequently the error message will contain more specific information than what is listed here.

Note that some non-fatal errors may be trapped and explicitly ignored in the Error event. This will allow the component to continue operation even in case of error.

Gzip Errors

102   The gzip archive is of an invalid or unsupported format.
111   Can't open file for read.
112   Can't open file for write.
113   Can't create directory.
114   The file is too large.
115   Can't create empty archive.
116   The archive must be scanned prior to attempting this operation.
117   The array index is out of range.
118   The maximum size of the archive has been exceeded.
119   The archive must be specified, or streaming must be enabled.
120   The component is busy.
124   Must specify the compressed name.
127   Bad CRC-32 checksum.
128   Unable to set file date.
133   File already exists in the archive.
150   An I/O error has occurred (details follow).

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IPWorks ZIP 2022 .NET Edition - Version 22.0 [Build 8214]