Bz2 Swift Reference Documentation

CkoBz2

Current Version: 11.5.0

Requires Chilkat Bundle License

Chilkat.Bz2 provides BZip2 compression and decompression for files, memory buffers, and BinData. It can create standard .bz2 file images, decompress .bz2 content back to its original bytes, and support abortable long-running operations.

For an extended overview, see Bz2 Class Overview

Object Creation

let obj = CkoBz2()!

Properties

AbortCurrent

abortCurrent: Bool

Introduced in version 9.5.0.58

Set this property to true to request cancellation of the compression or decompression operation currently executing on this object. Long-running operations check the request periodically; an operation that finishes quickly may complete before the request is observed.

A synchronous call can be cancelled by setting this property from another thread. After cancellation is processed, Chilkat resets the property to false. If no operation is running, a previously set value is cleared when the next method begins.

Cancellation is cooperative: Setting this property requests an abort; it does not guarantee immediate termination. Check the method's return value and LastErrorText to determine the final outcome.

DebugLogFilePath

debugLogFilePath: String!

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

A timeout property set to 0, indicating an infinite timeout.
A hang occurring within an event callback in the application code.
An internal bug in the Chilkat code causing the hang.

More Information and Examples

Example showing how to use DebugLogFilePath.

HeartbeatMs

heartbeatMs: Int

Specifies the interval, in milliseconds, between AbortCheck event callbacks during supported long-running compression and decompression operations. The default is 0, which disables AbortCheck callbacks.

Set a positive value, such as 200, when the application needs periodic opportunities to request cancellation. The interval is approximate; callbacks occur only while an operation is at a point where progress events can be delivered.

Cancellation workflow: In an AbortCheck handler, set the callback's abort value to request termination. A synchronous method may also be cancelled from another thread by setting AbortCurrent to true.

More Information and Examples

Event Callback Examples

LastErrorHtml

lastErrorHtml: String! (read-only)

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastErrorText

lastErrorText: String! (read-only)

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

lastErrorXml: String! (read-only)

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastMethodSuccess

lastMethodSuccess: Bool

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

VerboseLogging

verboseLogging: Bool

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version

version: String! (read-only)

Version of the component/library, such as "10.1.0"

More Information and Examples

How to get the Chilkat version at runtime.

Methods

CompressBd

compressBd(bd: CkoBinData) -> Bool

Introduced in version 11.0.0

Compresses the current contents of in place. On success, the BinData no longer contains the original bytes; it contains the complete standard BZip2 stream that may be saved with a .bz2 extension.

In-place transformation: Preserve a copy of the original data if it is still needed after this call. A BZip2 stream contains a stream header, one or more compressed blocks with integrity checks, and an end-of-stream marker. It does not contain archive filenames or directory entries.

Returns true for success, false for failure.

CompressBdAsync ⁽¹⁾

compressBdAsync(bd: CkoBinData) -> CkoTask

Introduced in version 11.0.0

Creates an asynchronous task to call the CompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressFile

compressFile(inPath: String, toPath: String) -> Bool

Reads the file at and writes its compressed bytes as a standard BZip2 stream to the file at toPath. The output is conventionally given a .bz2 extension.

Both arguments must identify files, not directories. They may be absolute or relative paths, for example data/report.txt and data/report.txt.bz2.

BZip2 is a compressor, not an archive format: A .bz2 file represents one compressed byte stream. It does not store the original filename, directory path, timestamps, permissions, or multiple archive entries. Formats such as .tar.bz2 first combine files in a TAR archive and then compress that TAR stream with BZip2.

Returns true for success, false for failure.

More Information and Examples

bz2 Compress File

CompressFileAsync ⁽¹⁾

compressFileAsync(inPath: String, toPath: String) -> CkoTask

Creates an asynchronous task to call the CompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressFileToMem

compressFile(toMem: String) -> NSData

Reads the file at toMem, compresses it with BZip2, and returns the complete .bz2 byte stream in memory.

Returns nil on failure

CompressFileToMemAsync ⁽¹⁾

compressFile(toMemAsync: String) -> CkoTask

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressMemory

compressMemory(inData: NSData) -> NSData

Compresses the bytes in and returns the complete standard BZip2 stream as an in-memory byte array.

Returns nil on failure

CompressMemoryAsync ⁽¹⁾

compressMemoryAsync(inData: NSData) -> CkoTask

Creates an asynchronous task to call the CompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressMemToFile

compressMem(toFile: NSData, toPath: String) -> Bool

Compresses the bytes in toFile and writes the resulting standard BZip2 stream to the file at toPath.

Returns true for success, false for failure.

CompressMemToFileAsync ⁽¹⁾

compressMem(toFileAsync: NSData, toPath: String) -> CkoTask

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

LoadTaskCaller

loadTaskCaller(task: CkoTask) -> Bool

Introduced in version 9.5.0.80

Loads this Bz2 object with the caller state associated with the asynchronous operation represented by .

Advanced async infrastructure: This method is used to recover the original caller object associated with a completed task. It is not normally needed by application code. Pass a Task created by a compatible Bz2 asynchronous method; an unrelated task cannot be loaded.

Returns true for success, false for failure.

UncompressBd

uncompressBd(bd: CkoBinData) -> Bool

Introduced in version 11.0.0

Decompresses the BZip2 stream currently contained in in place. On success, the BinData is replaced with the original uncompressed bytes.

Input requirement: must contain a complete, valid BZip2 stream, such as the bytes of a .bz2 file or the output of CompressBd. This method operates on binary data and does not perform character-set conversion.

Returns true for success, false for failure.

UncompressBdAsync ⁽¹⁾

uncompressBdAsync(bd: CkoBinData) -> CkoTask

Introduced in version 11.0.0

Creates an asynchronous task to call the UncompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressFile

uncompressFile(inPath: String, toPath: String) -> Bool

Reads the BZip2 stream from the file at , decompresses it, and writes the original uncompressed bytes to the file at toPath.

Both arguments must identify files, not directories. Chilkat does not derive the destination name from the .bz2 filename because the BZip2 stream does not contain the original filename.

Terminology: This method decompresses BZip2 data; it does not “unzip” a ZIP archive. A .bz2 file normally contains a single compressed byte stream rather than a collection of named files.

Returns true for success, false for failure.

UncompressFileAsync ⁽¹⁾

uncompressFileAsync(inPath: String, toPath: String) -> CkoTask

Creates an asynchronous task to call the UncompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressFileToMem

uncompressFile(toMem: String) -> NSData

Reads and decompresses the BZip2 stream in the file at toMem, returning the original uncompressed bytes in memory.

Returns nil on failure

UncompressFileToMemAsync ⁽¹⁾

uncompressFile(toMemAsync: String) -> CkoTask

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressMemory

uncompressMemory(inData: NSData) -> NSData

Interprets as a complete BZip2 stream and returns the decompressed bytes in memory.

Returns nil on failure

UncompressMemoryAsync ⁽¹⁾

uncompressMemoryAsync(inData: NSData) -> CkoTask

Creates an asynchronous task to call the UncompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressMemToFile

uncompressMem(toFile: NSData, toPath: String) -> Bool

Interprets toFile as a complete BZip2 stream, decompresses it, and writes the original bytes to the file at toPath.

Returns true for success, false for failure.

UncompressMemToFileAsync ⁽¹⁾

uncompressMem(toFileAsync: NSData, toPath: String) -> CkoTask

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

Events

To implement an event callback, your application would define and implement a class that inherits from CkoBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkoBaseProgress base class.

For example:

class MyBz2Progress : CkoBaseProgress {

    override func ProgressInfo(name: String!, value: String!) {
        // application code goes here...
        print(name + ": " + value)
    }

    override func AbortCheck(abort: UnsafeMutablePointer) {
        // application code goes here...
        // To abort the operation, set this equal to true instead of false.
        abort.memory = false
    }

    override func PercentDone(pctDone: NSNumber!, abort: UnsafeMutablePointer) {
        // application code goes here...
        print(pctDone)
        // To abort the operation, set this equal to true instead of false.
        abort.memory = false
    }

    // For asynchronous method calls.
    override func TaskCompleted(task: CkoTask!) {
        // application code goes here...
    }
}

func someAppFunction() {

    // Demonstrate how to set the event callback object...
    let bz = CkoBz2()
    let myBzProgress = MyBz2Progress()
    
    bz.setEventCallbackObject(myBzProgress)

    // ...
    // ...
    // ...
}

AbortCheck

abortCheck(abort: Bool)

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

More Information and Examples

Chilkat Event Callback Examples

PercentDone

percentDone(pctDone: Int, abort: Bool)

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the abort output argument to true. This will cause the method to terminate and return a failure status or corresponding failure value.

More Information and Examples

Chilkat Event Callback Examples

ProgressInfo

progressInfo(name: String, value: String)

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

More Information and Examples

Chilkat Event Callback Examples

TaskCompleted

taskCompleted(task: CkoTask)

Called from the background thread when an asynchronous task completes.

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