# Gzip Component

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

```text
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](#archivefile-property-gzip-component) to the name of the gzip file to be created, and [FileDecompressedName](#filedecompressedname-property-gzip-component) to the name of the file to be compressed. Finally, invoke [Compress](#compress-method-gzip-component). To extract the file, first set [ArchiveFile](#archivefile-property-gzip-component). [FileDecompressedName](#filedecompressedname-property-gzip-component) may then be set; if not, it will automatically be set from the gzip file headers. Finally, invoke the [Extract](#extract-method-gzip-component) or [Compress](#compress-method-gzip-component) 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)**

```text
ZipControl.ArchiveFile = "c:\test.gz"
ZipControl.FileDecompressedName = "c:\test.txt"
ZipControl.Compress()
```

 **Example (Extracting from a Gzip File)**

```text
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.*

|  |  |
| --- | --- |
| [ArchiveFile](#archivefile-property-gzip-component) | The name of the zip, gzip, tar, or jar archive. |
| [CompressionLevel](#compressionlevel-property-gzip-component) | The compression level to use. |
| [CompressionMethod](#compressionmethod-property-gzip-component) | The compression method for the component to use. |
| [ExtractToPath](#extracttopath-property-gzip-component) | A base path to decompress to. |
| [FileCompressedDate](#filecompresseddate-property-gzip-component) | The date and time of the compressed file, as stored within the gzip archive. |
| [FileCompressedName](#filecompressedname-property-gzip-component) | Filename, as stored inside of the archive. |
| [FileDecompressedName](#filedecompressedname-property-gzip-component) | File name to decompress to, or compress from. |
| [FileDecompressedSize](#filedecompressedsize-property-gzip-component) | Gets the size of the file, as decompressed outside the archive. |
| [FileInputData](#fileinputdata-property-gzip-component) | The data of the file to be compressed. |
| [GzipData](#gzipdata-property-gzip-component) | (Decompression only) The gzip file contents as a byte array. |
| [HasMoreData](#hasmoredata-property-gzip-component) | Shows 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.*

|  |  |
| --- | --- |
| [Abort](#abort-method-gzip-component) | Aborts the current operation. |
| [Append](#append-method-gzip-component) | Adds specified file to an existing archive. |
| [Compress](#compress-method-gzip-component) | Creates the compressed gzip archive. |
| [Config](#config-method-gzip-component) | Sets or retrieves a configuration setting. |
| [Extract](#extract-method-gzip-component) | Extracts the compressed file from the gzip archive. |
| [ExtractAll](#extractall-method-gzip-component) | Extracts all files from the compressed archive. |
| [Reset](#reset-method-gzip-component) | Resets the component. |
| [Scan](#scan-method-gzip-component) | Scans the compressed archive. |
| [SetArchiveInputStream](#setarchiveinputstream-method-gzip-component) | The stream to read the zip, tar, jar, or gzip archive from. |
| [SetArchiveOutputStream](#setarchiveoutputstream-method-gzip-component) | The stream to write the zip, tar, jar, or gzip archive to. |
| [SetFileInputStream](#setfileinputstream-method-gzip-component) | The 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.*

|  |  |
| --- | --- |
| [BeginFile](#beginfile-event-gzip-component) | Fired before a file is processed. |
| [EndFile](#endfile-event-gzip-component) | Fired after a file is processed. |
| [Error](#error-event-gzip-component) | Information about non-fatal errors. |
| [Overwrite](#overwrite-event-gzip-component) | Fired whenever a file exists and may be overwritten. |
| [Progress](#progress-event-gzip-component) | Fired as progress is made. |

## Config Settings

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

|  |  |
| --- | --- |
| [CloseStreamAfterCompress](#CloseStreamAfterCompress) | If true, the component will close the output stream after compression. |
| [FileComment](#FileComment) | Holds the comment associated with the archive. |
| [PreserveModifiedTime](#PreserveModifiedTime) | Whether or not to preserve the original modified time on extracted files. |
| [WriteToProgressEvent](#WriteToProgressEvent) | Whether or not to write data to the Progress Event. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [GUIAvailable](#GUIAvailable) | Whether or not a message loop is available for processing events. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# ArchiveFile Property ([Gzip](#gzip-component) Component)

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

## Syntax

```text
public string ArchiveFile { get; set; }
```

## 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](#scan-method-gzip-component), [Extract](#extract-method-gzip-component), or [ExtractAll](#extractall-method-gzip-component) 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](#compress-method-gzip-component) is called, the file named by ArchiveFile will be written; if a file of this name already exists the [Overwrite](#overwrite-event-gzip-component) 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](#progress-event-gzip-component) 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)**

```text
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](#gzip-component) Component)

The compression level to use.

## Syntax

```text
public int CompressionLevel { get; set; }
```

## 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](#gzip-component) Component)

The compression method for the component to use.

## Syntax

```text
public GzipCompressionMethods CompressionMethod { get; set; }
enum GzipCompressionMethods {
  cmgDeflate,
  cmgLZCCompress
}
```

## 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](#gzip-component) Component)

A base path to decompress to.

## Syntax

```text
public string ExtractToPath { get; set; }
```

## Default Value

""

## Remarks

Setting the ExtractToPath property affects the operation of the [Extract](#extract-method-gzip-component) and [ExtractAll](#extractall-method-gzip-component) 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](#filedecompressedname-property-gzip-component) 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)**

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

# FileCompressedDate Property ([Gzip](#gzip-component) Component)

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

## Syntax

```text
public long FileCompressedDate { get; }
```

## 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](#scan-method-gzip-component) or [Extract](#extract-method-gzip-component). 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](#gzip-component) Component)

Filename, as stored inside of the archive.

## Syntax

```text
public string FileCompressedName { get; set; }
```

## 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 (paths beginning with a */* character) 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](#compress-method-gzip-component) if it is not specified, and it will always be written by a call to [Scan](#scan-method-gzip-component) or [Extract](#extract-method-gzip-component).

# FileDecompressedName Property ([Gzip](#gzip-component) Component)

File name to decompress to, or compress from.

## Syntax

```text
public string FileDecompressedName { get; set; }
```

## 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](#compress-method-gzip-component) 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](#scan-method-gzip-component) and prior to calling [Extract](#extract-method-gzip-component). If this property is set to the empty string when [Extract](#extract-method-gzip-component) is called, [Extract](#extract-method-gzip-component) will automatically set this property to an appropriate value.

NOTE: If [Scan](#scan-method-gzip-component) is not called before [Extract](#extract-method-gzip-component), 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](#gzip-component) Component)

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

## Syntax

```text
public long FileDecompressedSize { get; }
```

## 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](#gzip-component) Component)

The data of the file to be compressed.

## Syntax

```text
public string FileInputData { get; set; }
public byte[] FileInputDataB { get; set; }
```

## 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](#filedecompressedname-property-gzip-component) property.

This property is not available at design time.

# GzipData Property ([Gzip](#gzip-component) Component)

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

## Syntax

```text
public string GzipData { set; }
public byte[] GzipDataB { set; }
```

## Default Value

""

## Remarks

Normally you should set [ArchiveFile](#archivefile-property-gzip-component) before invoking [Scan](#scan-method-gzip-component) or [Extract](#extract-method-gzip-component). 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](#WriteToProgressEvent) to true, and after invoking [Scan](#scan-method-gzip-component), you should set the value of [FileDecompressedName](#filedecompressedname-property-gzip-component) to an empty string. Then, when you invoke [Extract](#extract-method-gzip-component) (or [ExtractAll](#extractall-method-gzip-component)) the data will be provided in the [Progress](#progress-event-gzip-component) event.

This property is write-only. Note that modifying a gzip file stored in GzipData is not supported, so [Append](#append-method-gzip-component) will throw exceptions.

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

# HasMoreData Property ([Gzip](#gzip-component) Component)

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

## Syntax

```text
public bool HasMoreData { get; }
```

## 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](#archivefile-property-gzip-component) and [ExtractToPath](#extracttopath-property-gzip-component) properties, then call [Extract](#extract-method-gzip-component) as long as the component has available data.

**Note**: the component will not update [FileDecompressedName](#filedecompressedname-property-gzip-component) unless you call [Scan](#scan-method-gzip-component) or manually set [FileDecompressedName](#filedecompressedname-property-gzip-component) on each loop before calling [Extract](#extract-method-gzip-component).

**Example (Extracting Multiple Files)**

```text
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](#gzip-component) Component)

Aborts the current operation.

## Syntax

```text
public void Abort();

Async Version
public async Task Abort();
public async Task Abort(CancellationToken cancellationToken);
```

## Remarks

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

# Append Method ([Gzip](#gzip-component) Component)

Adds specified file to an existing archive.

## Syntax

```text
public void Append();

Async Version
public async Task Append();
public async Task Append(CancellationToken cancellationToken);
```

## Remarks

The file contained in the [FileDecompressedName](#filedecompressedname-property-gzip-component) property will be appended to the archive specified by [ArchiveFile](#archivefile-property-gzip-component).

This method may only be used to add files to an existing archive. To add files to a new archive, [Compress](#compress-method-gzip-component) method should be used.

# Compress Method ([Gzip](#gzip-component) Component)

Creates the compressed gzip archive.

## Syntax

```text
public void Compress();

Async Version
public async Task Compress();
public async Task Compress(CancellationToken cancellationToken);
```

## Remarks

Invoking Compress creates the archive specified by [ArchiveFile](#archivefile-property-gzip-component). When the method is called, the file specified by [FileDecompressedName](#filedecompressedname-property-gzip-component) will be opened, and the file specified by [ArchiveFile](#archivefile-property-gzip-component) will contain the compressed output.

The filename to be stored within the archive is given by [FileCompressedName](#filecompressedname-property-gzip-component). 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](#progress-event-gzip-component) 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](#gzip-component) Component)

Sets or retrieves a configuration setting.

## Syntax

```text
public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
```

## Remarks

Config is a generic method available in every component. It is used to set and retrieve [configuration settings](#config-settings-gzip-component) 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](#config-settings-gzip-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# Extract Method ([Gzip](#gzip-component) Component)

Extracts the compressed file from the gzip archive.

## Syntax

```text
public void Extract();

Async Version
public async Task Extract();
public async Task Extract(CancellationToken cancellationToken);
```

## Remarks

Invoking Extract decompresses the archive specified by [ArchiveFile](#archivefile-property-gzip-component). The compressed file will be extracted, and written to disk. Also, [FileCompressedName](#filecompressedname-property-gzip-component) will be set to the filename found in the archive.

If [FileDecompressedName](#filedecompressedname-property-gzip-component) is set to a nonempty string the file will be written there. Otherwise the component will automatically set [FileDecompressedName](#filedecompressedname-property-gzip-component) to an appropriate value:

If a filename (i.e., [FileCompressedName](#filecompressedname-property-gzip-component)) is stored in the gzip headers, this filename will be used.

Otherwise, if [ArchiveFile](#archivefile-property-gzip-component) 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](#archivefile-property-gzip-component).

# ExtractAll Method ([Gzip](#gzip-component) Component)

Extracts all files from the compressed archive.

## Syntax

```text
public void ExtractAll();

Async Version
public async Task ExtractAll();
public async Task ExtractAll(CancellationToken cancellationToken);
```

## Remarks

ExtractAll extracts all files from the archive. The file(s) will be extracted to the directory specified by [ExtractToPath](#extracttopath-property-gzip-component), and given the names found in the archive or specified by [FileDecompressedName](#filedecompressedname-property-gzip-component).

If [Scan](#scan-method-gzip-component) has not been invoked when ExtractAll is called, [Scan](#scan-method-gzip-component) will automatically be invoked, and the [FileCompressedName](#filecompressedname-property-gzip-component) and [FileDecompressedName](#filedecompressedname-property-gzip-component) properties will be set to the values found in the archive. To manually set the decompressed filenames, [Scan](#scan-method-gzip-component) should be invoked before setting [FileDecompressedName](#filedecompressedname-property-gzip-component).

The [BeginFile](#beginfile-event-gzip-component) and [EndFile](#endfile-event-gzip-component) events will be fired before and after each file is extracted, and the [Progress](#progress-event-gzip-component) event will be fired as the data is extracted. If [WriteToProgressEvent](#WriteToProgressEvent) is set to true, the decompressed data will be streamed out through the [Progress](#progress-event-gzip-component) event.

**Example (Extracting from an Archive)**

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

# Reset Method ([Gzip](#gzip-component) Component)

Resets the component.

## Syntax

```text
public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
```

## 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](#gzip-component) Component)

Scans the compressed archive.

## Syntax

```text
public void Scan();

Async Version
public async Task Scan();
public async Task Scan(CancellationToken cancellationToken);
```

## Remarks

This method will scan the gzip archive specified by [ArchiveFile](#archivefile-property-gzip-component). The archive will be read, the header will be checked, and the stored filename will be written to [FileCompressedName](#filecompressedname-property-gzip-component).

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](#extract-method-gzip-component). Suggested uses for this method would be to check that the file is a gzip file, or to determine an appropriate value for [FileDecompressedName](#filedecompressedname-property-gzip-component).

# SetArchiveInputStream Method ([Gzip](#gzip-component) Component)

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

## Syntax

```text
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);
```

## Remarks

This method should be set when the archive is to be read from a stream when [Extract](#extract-method-gzip-component) is called.

By default, and when this is set to null, the component will read from the file specified by [ArchiveFile](#archivefile-property-gzip-component). However, when this is a valid stream, the data will be read from the stream.

# SetArchiveOutputStream Method ([Gzip](#gzip-component) Component)

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

## Syntax

```text
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);
```

## Remarks

This method should be set when the archive is to be written to a stream when [Compress](#compress-method-gzip-component) is called.

By default, and when this is set to null, the component will write to the file specified by [ArchiveFile](#archivefile-property-gzip-component). However, when this is a valid stream, the data will be written to the stream.

# SetFileInputStream Method ([Gzip](#gzip-component) Component)

The input stream to read the decompressed data from.

## Syntax

```text
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);
```

## 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](#filedecompressedname-property-gzip-component) property.

# BeginFile Event ([Gzip](#gzip-component) Component)

Fired before a file is processed.

## Syntax

```text
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; }
}
```

## 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](#gzip-component) Component)

Fired after a file is processed.

## Syntax

```text
public event OnEndFileHandler OnEndFile;

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

public class GzipEndFileEventArgs : EventArgs {
  public int Index { get; }
}
```

## Remarks

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

# Error Event ([Gzip](#gzip-component) Component)

Information about non-fatal errors.

## Syntax

```text
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; }
}
```

## 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:

|  |  |
| --- | --- |
| 1 | Bad or missing CRC-32 checksum. |
| 2 | Failed to set creation date of a file. |
| 111 | Can'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](#gzip-component) Component)

Fired whenever a file exists and may be overwritten.

## Syntax

```text
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; }
}
```

## 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](#gzip-component) Component)

Fired as progress is made.

## Syntax

```text
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; }
}
```

## Remarks

The Progress event is automatically fired as compression or decompression is performed. When [WriteToProgressEvent](#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](#WriteToProgressEvent) is false, *Data* will contain null.

# Config Settings ([Gzip](#gzip-component) 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](#config-method-gzip-component) method.

### Gzip Config 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](#scan-method-gzip-component).

**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](#WriteToProgressEvent) is set to true, then all data produced through invocations of [Extract](#extract-method-gzip-component), [ExtractAll](#extractall-method-gzip-component), and [Compress](#compress-method-gzip-component) will be written to the [Progress](#progress-event-gzip-component) 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](#WriteToProgressEvent) is set to false, the data will not be streamed out, and the *Data* parameter of the [Progress](#progress-event-gzip-component) event will contain null.

By default, this config is set to false.

### Base Config Settings

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

**GUIAvailable**: 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](#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.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *true* to mask sensitive data. The default is *true*.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, 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 configuration setting to *true* tells the component to use the internal implementation instead of using the system security libraries.

 On Windows, this setting is set to *false* by default. On Linux/macOS, this setting is set to *true* by default.

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 dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

# Trappable Errors ([Gzip](#gzip-component) 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](#error-event-gzip-component) 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). |