Struct ipworkszip::Bzip2

Properties   Methods   Events   Config Settings   Errors  

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

Syntax

ipworkszip::Bzip2

Remarks

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

To compress with the struct, set archive_file to the name of the bzip2 file to be created, and file_decompressed_name to the name of the file to be compressed. Finally, invoke compress. To extract the file, set archive_file to the bzip2 archive and file_decompressed_name to the file where the struct 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 struct is an implementation based on Julian Seward's bzip2 library (http://www.bzip.org).

Object Lifetime

The new() method returns a mutable reference to a struct instance. The object itself is kept in the global list maintained by IPWorksZip. Due to this, the Bzip2 struct cannot be disposed of automatically. Please, call the dispose(&mut self) method of Bzip2 when you have finished using the instance.

Property List

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

Method List

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

Event List

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

Config Settings

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

archive_file property (Bzip2 Struct)

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

Syntax

fn archive_file(&self ) -> Result<String, IPWorksZipError> 
fn set_archive_file(&self, value : &str) ->  Option<IPWorksZipError> 
fn set_archive_file_ref(&self, value : &String) ->  Option<IPWorksZipError> 

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 extract_all is invoked, the file specified by archive_file 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 archive_file will be written; if a file of this name already exists the on_overwrite event will be fired. If archive_file is set to the empty string (""), the archive will not be written to disk, and will be provided only through the on_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 struct.

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 archive_file to the empty string ("").

Data Type

String

bzip2_data property (Bzip2 Struct)

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

Syntax

fn set_bzip2_data(&self, value : Vec<u8>) ->  Option<IPWorksZipError> 
fn set_bzip2_data_ref(&self, value : &[u8]) ->  Option<IPWorksZipError> 

Default Value

""

Remarks

Normally you should set archive_file before invoking scan or extract. If you prefer to read the bzip2 file from memory you may set bzip2_data instead. bzip2_data 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 file_decompressed_name to an empty string. Then, when you invoke extract (or extract_all) the data will be provided in the on_progress event.

This property is write-only. Note that modifying a bzip2 file stored in bzip2_data is not supported, so append will throw exceptions.

This property is write-only.

Data Type

Vec

extract_to_path property (Bzip2 Struct)

A base path to decompress to.

Syntax

fn extract_to_path(&self ) -> Result<String, IPWorksZipError> 
fn set_extract_to_path(&self, value : &str) ->  Option<IPWorksZipError> 
fn set_extract_to_path_ref(&self, value : &String) ->  Option<IPWorksZipError> 

Default Value

""

Remarks

Setting the extract_to_path property affects the operation of the extract and extract_all 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 file_decompressed_name they will be regarded as relative to extract_to_path.

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

extract_to_path 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

file_decompressed_name property (Bzip2 Struct)

File name to decompress to, or compress from.

Syntax

fn file_decompressed_name(&self ) -> Result<String, IPWorksZipError> 
fn set_file_decompressed_name(&self, value : &str) ->  Option<IPWorksZipError> 
fn set_file_decompressed_name_ref(&self, value : &String) ->  Option<IPWorksZipError> 

Default Value

""

Remarks

file_decompressed_name 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 struct. 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

file_input_data property (Bzip2 Struct)

The data of the file to be compressed.

Syntax

fn file_input_data(&self ) -> Result<Vec<u8>, IPWorksZipError> 
fn set_file_input_data(&self, value : Vec<u8>) ->  Option<IPWorksZipError> 
fn set_file_input_data_ref(&self, value : &[u8]) ->  Option<IPWorksZipError> 

Default Value

""

Remarks

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

Data Type

Vec

has_more_data property (Bzip2 Struct)

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

Syntax

fn has_more_data(&self ) -> Result<bool, IPWorksZipError> 

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 has_more_data property can be used to cycle through the archive and extract each file.

Simply set the archive_file and extract_to_path properties, then call extract as long as the struct has available data.

Note: the struct will not update file_decompressed_name unless you manually set file_decompressed_name 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 file_decompressed_name prior to extraction ZipControl.Extract() While ZipControl.HasMoreData

This property is read-only.

Data Type

bool

abort method (Bzip2 Struct)

Aborts the current operation.

Syntax

fn abort(&self) -> Result<(), IPWorksZipError>

Remarks

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

append method (Bzip2 Struct)

Adds specified file to an existing archive.

Syntax

fn append(&self) -> Result<(), IPWorksZipError>

Remarks

The file contained in the file_decompressed_name property will be appended to the archive specified by archive_file.

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 Struct)

Creates the compressed bzip2 archive.

Syntax

fn compress(&self) -> Result<(), IPWorksZipError>

Remarks

Invoking compress creates the archive specified by archive_file. When the method is called, the file specified by file_decompressed_name will be opened, and the file specified by archive_file will contain the compressed output.

As the data is compressed the on_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 Struct)

Sets or retrieves a configuration setting.

Syntax

fn config(&self, configuration_string : &str) ->  Result<String, IPWorksZipError>

Remarks

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

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

Extracts the compressed file from the bzip2 archive.

Syntax

fn extract(&self) -> Result<(), IPWorksZipError>

Remarks

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

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

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

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

extract_all method (Bzip2 Struct)

Extracts all files from the compressed archive.

Syntax

fn extract_all(&self) -> Result<(), IPWorksZipError>

Remarks

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

The on_begin_file and on_end_file events will be fired before and after each file is extracted, and the on_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 on_progress event.

reset method (Bzip2 Struct)

Resets the struct.

Syntax

fn reset(&self) -> Result<(), IPWorksZipError>

Remarks

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

scan method (Bzip2 Struct)

Scans the compressed archive.

Syntax

fn scan(&self) -> Result<(), IPWorksZipError>

Remarks

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

Unlike in the Zip, Tar, and Jar structs, 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.

on_begin_file event (Bzip2 Struct)

Fired before a file is processed.

Syntax

// Bzip2BeginFileEventArgs carries the Bzip2 BeginFile event's parameters.
pub struct Bzip2BeginFileEventArgs {
  fn index(&self) -> i32
  fn skip(&self) -> bool
  fn set_skip(&self, value : bool)
}

// Bzip2BeginFileEvent defines the signature of the Bzip2 BeginFile event's handler function.
pub trait Bzip2BeginFileEvent {
  fn on_begin_file(&self, sender : Bzip2, e : &mut Bzip2BeginFileEventArgs);
}

impl <'a> Bzip2<'a> {
  pub fn on_begin_file(&self) -> &'a dyn Bzip2BeginFileEvent;
  pub fn set_on_begin_file(&mut self, value : &'a dyn Bzip2BeginFileEvent);
  ...
}

Remarks

on_begin_file is fired before compression or decompression begins. index will contain 0.

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

on_end_file event (Bzip2 Struct)

Fired after a file is processed.

Syntax

// Bzip2EndFileEventArgs carries the Bzip2 EndFile event's parameters.
pub struct Bzip2EndFileEventArgs {
  fn index(&self) -> i32
}

// Bzip2EndFileEvent defines the signature of the Bzip2 EndFile event's handler function.
pub trait Bzip2EndFileEvent {
  fn on_end_file(&self, sender : Bzip2, e : &mut Bzip2EndFileEventArgs);
}

impl <'a> Bzip2<'a> {
  pub fn on_end_file(&self) -> &'a dyn Bzip2EndFileEvent;
  pub fn set_on_end_file(&mut self, value : &'a dyn Bzip2EndFileEvent);
  ...
}

Remarks

on_end_file is fired when compression or decompression finishes. index will contain 0.

on_error event (Bzip2 Struct)

Information about non-fatal errors.

Syntax

// Bzip2ErrorEventArgs carries the Bzip2 Error event's parameters.
pub struct Bzip2ErrorEventArgs {
  fn description(&self) -> &String
  fn error_code(&self) -> i32
  fn index(&self) -> i32
  fn file_name(&self) -> &String
  fn ignore(&self) -> bool
  fn set_ignore(&self, value : bool)
}

// Bzip2ErrorEvent defines the signature of the Bzip2 Error event's handler function.
pub trait Bzip2ErrorEvent {
  fn on_error(&self, sender : Bzip2, e : &mut Bzip2ErrorEventArgs);
}

impl <'a> Bzip2<'a> {
  pub fn on_error(&self) -> &'a dyn Bzip2ErrorEvent;
  pub fn set_on_error(&mut self, value : &'a dyn Bzip2ErrorEvent);
  ...
}

Remarks

The on_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 struct will continue operation.

error_code will correspond to one of the following errors:

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

on_overwrite event (Bzip2 Struct)

Fired whenever a file exists and may be overwritten.

Syntax

// Bzip2OverwriteEventArgs carries the Bzip2 Overwrite event's parameters.
pub struct Bzip2OverwriteEventArgs {
  fn file_name(&self) -> &String
  fn set_file_name(&self, value : &str)
  fn set_file_name_ref(&self, value : &String)
  fn overwrite(&self) -> bool
  fn set_overwrite(&self, value : bool)
}

// Bzip2OverwriteEvent defines the signature of the Bzip2 Overwrite event's handler function.
pub trait Bzip2OverwriteEvent {
  fn on_overwrite(&self, sender : Bzip2, e : &mut Bzip2OverwriteEventArgs);
}

impl <'a> Bzip2<'a> {
  pub fn on_overwrite(&self) -> &'a dyn Bzip2OverwriteEvent;
  pub fn set_on_overwrite(&mut self, value : &'a dyn Bzip2OverwriteEvent);
  ...
}

Remarks

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

file_name 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 overwrite_files 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 struct, and cause the file to be overwritten or not overwritten, depending on the value set. If file_name 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.

on_progress event (Bzip2 Struct)

Fired as progress is made.

Syntax

// Bzip2ProgressEventArgs carries the Bzip2 Progress event's parameters.
pub struct Bzip2ProgressEventArgs {
  fn data(&self) -> &[u8]
  fn file_name(&self) -> &String
  fn bytes_processed(&self) -> i64
  fn percent_processed(&self) -> i32
}

// Bzip2ProgressEvent defines the signature of the Bzip2 Progress event's handler function.
pub trait Bzip2ProgressEvent {
  fn on_progress(&self, sender : Bzip2, e : &mut Bzip2ProgressEventArgs);
}

impl <'a> Bzip2<'a> {
  pub fn on_progress(&self) -> &'a dyn Bzip2ProgressEvent;
  pub fn set_on_progress(&mut self, value : &'a dyn Bzip2ProgressEvent);
  ...
}

Remarks

The on_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.

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

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

For Gzip extraction only, bytes_processed and percent_processed 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 Struct)

The struct 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 struct, access to these internal properties is provided through the config method.

Bzip2 Config Settings

Base Config Settings

Trappable Errors (Bzip2 Struct)

Errors

The following errors may be generated by the struct. 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 on_error event. This will allow the struct to continue operation even in case of error.

Bzip2 Errors