Bzip2 Control

Properties   Methods   Events   Config Settings   Errors  

The Bzip2 control implements a bzip2 compressor and decompressor. It is compliant with bzip2 specification.

Syntax

Bzip2

Remarks

The bzip2 file format is typically used only to archive a single file. Accordingly, the operation of the control is simpler than that of the other controls.

To compress with the control, set ArchiveFile to the name of the bzip2 file to be created, and FileDecompressedName to the name of the file to be compressed. Finally, invoke Compress. To extract the file, set ArchiveFile to the bzip2 archive and FileDecompressedName to the file where the control should extract. Finally, invoke the Extract or Compress method.

Example (Creating a Bzip2 File)

ZipControl.ArchiveFile = "c:\test.bz2" ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Compress() Example (Extracting from a Bzip2 File)

ZipControl.ArchiveFile = "c:\test.bz2" ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Extract()

This control is an implementation based on Julian Seward's bzip2 library (http://www.bzip.org).

Property List


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

ArchiveFileThe name of the zip, gzip, tar, or jar archive.
Bzip2Data(Decompression only) The bzip2 file contents as a byte array.
ExtractToPathA base path to decompress to.
FileDecompressedNameFile name to decompress to, or compress from.
FileInputDataThe data of the file to be compressed.
HasMoreDataShows whether or not there is more data in the bzip2 archive.

Method List


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

AbortAborts the current operation.
AppendAdds specified file to an existing archive.
CompressCreates the compressed bzip2 archive.
ConfigSets or retrieves a configuration setting.
ExtractExtracts the compressed file from the bzip2 archive.
ExtractAllExtracts all files from the compressed archive.
ResetResets the control.
ScanScans the compressed archive.

Event List


The following is the full list of the events fired by the control 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.

Config Settings


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

WriteToProgressEventWhether or not to write data to the Progress Event.
CodePageThe system code page used for Unicode to Multibyte translations.
MaskSensitiveDataWhether sensitive data is masked in log messages.
UseInternalSecurityAPIWhether or not to use the system security libraries or an internal implementation.

ArchiveFile Property (Bzip2 Control)

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

Syntax

bzip2control.ArchiveFile[=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 control.

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 ("").

Data Type

String

Bzip2Data Property (Bzip2 Control)

(Decompression only) The bzip2 file contents as a byte array.

Syntax

bzip2control.Bzip2Data[=string]

Default Value

""

Remarks

Normally you should set ArchiveFile before invoking Scan or Extract. If you prefer to read the bzip2 file from memory you may set Bzip2Data instead. Bzip2Data should be set to the entire contents of the bzip2 file; this will allow you to read from the bzip2 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 bzip2 file stored in Bzip2Data is not supported, so Append will throw exceptions.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .Bzip2DataB.

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

Data Type

Binary String

ExtractToPath Property (Bzip2 Control)

A base path to decompress to.

Syntax

bzip2control.ExtractToPath[=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.

Data Type

String

FileDecompressedName Property (Bzip2 Control)

File name to decompress to, or compress from.

Syntax

bzip2control.FileDecompressedName[=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 control. 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 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.

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.

Data Type

String

FileInputData Property (Bzip2 Control)

The data of the file to be compressed.

Syntax

bzip2control.FileInputData[=string]

Default Value

""

Remarks

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

To read or write binary data to the property, a Variant (Byte Array) version is provided in .FileInputDataB.

This property is not available at design time.

Data Type

Binary String

HasMoreData Property (Bzip2 Control)

Shows whether or not there is more data in the bzip2 archive.

Syntax

bzip2control.HasMoreData

Default Value

False

Remarks

The bzip2 format allows multiple bzip2 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 control has available data.

Note: the control will not update FileDecompressedName unless you manually set FileDecompressedName on each loop before calling Extract.

Example (Extracting Multiple Files)

ZipControl.ArchiveFile = "c:\temp.bz2" ZipControl.ExtractToPath = "c:\extracted\" Do //here you may set the file name in FileDecompressedName prior to extraction ZipControl.Extract() While ZipControl.HasMoreData

This property is read-only.

Data Type

Boolean

Abort Method (Bzip2 Control)

Aborts the current operation.

Syntax

bzip2control.Abort 

Remarks

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

Append Method (Bzip2 Control)

Adds specified file to an existing archive.

Syntax

bzip2control.Append 

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 (Bzip2 Control)

Creates the compressed bzip2 archive.

Syntax

bzip2control.Compress 

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.

As the data is compressed the Progress event will be fired at regular intervals. This event may be used to stream out the bzip2 file, or to display a progress bar to the user.

Config Method (Bzip2 Control)

Sets or retrieves a configuration setting.

Syntax

bzip2control.Config ConfigurationString

Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, 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 (Bzip2 Control)

Extracts the compressed file from the bzip2 archive.

Syntax

bzip2control.Extract 

Remarks

Invoking Extract decompresses the archive specified by ArchiveFile. The compressed file will be extracted, and written to disk.

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

If ArchiveFile ends in ".bz2", this filename, less the ".bz2" extension will be used.

If this condition does not hold, ".unzipped" will be appended to ArchiveFile.

ExtractAll Method (Bzip2 Control)

Extracts all files from the compressed archive.

Syntax

bzip2control.ExtractAll 

Remarks

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

Reset Method (Bzip2 Control)

Resets the control.

Syntax

bzip2control.Reset 

Remarks

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

Scan Method (Bzip2 Control)

Scans the compressed archive.

Syntax

bzip2control.Scan 

Remarks

This method will scan the bzip archive specified by ArchiveFile. The archive will be read, and the header will be checked.

Unlike in the Zip, Tar, and Jar controls, 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 bzip file.

BeginFile Event (Bzip2 Control)

Fired before a file is processed.

Syntax

Sub bzip2control_BeginFile(Index As Integer, Skip As Boolean)

Remarks

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

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

EndFile Event (Bzip2 Control)

Fired after a file is processed.

Syntax

Sub bzip2control_EndFile(Index As Integer)

Remarks

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

Error Event (Bzip2 Control)

Information about non-fatal errors.

Syntax

Sub bzip2control_Error(Description As String, ErrorCode As Integer, Index As Integer, Filename As String, Ignore As Boolean)

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 control 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 (Bzip2 Control)

Fired whenever a file exists and may be overwritten.

Syntax

Sub bzip2control_Overwrite(Filename As String, Overwrite As Boolean)

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 control, 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 (Bzip2 Control)

Fired as progress is made.

Syntax

Sub bzip2control_Progress(Data As String, Filename As String, BytesProcessed As Long64, PercentProcessed As Integer)

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.

Config Settings (Bzip2 Control)

The control 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 control, access to these internal properties is provided through the Config method.

Bzip2 Config Settings

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 Config Settings

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8
The following is a list of valid code page identifiers for Mac OS only:
IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

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 to mask sensitive data. The default is .

This setting only works on these controls: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

UseInternalSecurityAPI:   Whether or not to use the system security libraries or an internal implementation.

When set to , the control will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to tells the control to use the internal implementation instead of using the system security libraries.

This setting is set to by default on all platforms.

Trappable Errors (Bzip2 Control)

Errors

The following errors may be generated by the control. 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 control to continue operation even in case of error.

Bzip2 Errors

20112    Can't open file for read.
20113    Can't open file for write.
20114    Can't create directory.
20115    The file is too large.
20116    Can't create empty archive.
20117    The archive must be scanned prior to attempting this operation.
20118    The array index is out of range.
20119    The maximum size of the archive has been exceeded.
20120    The archive must be specified, or streaming must be enabled.
20121    The component is busy.
20125    Must specify the compressed name.
20128    Bad CRC-32 checksum.
20129    Unable to set file date.
20134    File already exists in the archive.
20151    An I/O error has occurred (details follow).