---
product: Chilkat
product_version: 11.7.0
language: csharp
language_label: C#
class: Bz2
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/csBz2Ref.html
---
# Chilkat Bz2 — C# — v11.7.0

> Chilkat 11.7.0 · language=csharp · class=Bz2
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/Bz2.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/guide.md`.

## Purpose

`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](https://www.chilkatsoft.com/bz2_class_overview.asp)

## Object creation, unlocking and error handling

**Object Creation**

```csharp
Chilkat.Bz2 obj = new Chilkat.Bz2();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in C#.

Minimal complete program:

```csharp
// Required once per process. Any string unlocks a 30-day trial; use your purchased code in production.
Chilkat.Global glob = new Chilkat.Global();
if (!glob.UnlockBundle("Anything for 30-day trial"))
{
    Console.WriteLine(glob.LastErrorText);
    return;
}

Chilkat.Bz2 bz2 = new Chilkat.Bz2();

bool success = bz2.CompressFile("<inFilename>", "<toPath>");
if (!success)
{
    Console.WriteLine(bz2.LastErrorText);   // full diagnostic of what went wrong
    return;
}
```

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `public string DebugLogFilePath {get; set; }` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `public string LastErrorHtml {get; }` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `public string LastErrorText {get; }` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `public string LastErrorXml {get; }` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `public bool LastMethodSuccess {get; set; }` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `public bool VerboseLogging {get; set; }` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `public string Version {get; }` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AbortCurrent` | property, read/write | `public bool AbortCurrent {get; set; }` |
| `HeartbeatMs` | property, read/write | `public int HeartbeatMs {get; set; }` |
| `CompressBd` | method | `public bool CompressBd(BinData bd);` |
| `CompressFile` | method | `public bool CompressFile(string inFilename, string toPath);` |
| `CompressFileToMem` | method | `public byte[] CompressFileToMem(string inFilename);` |
| `CompressMemory` | method | `public byte[] CompressMemory(byte[] inData);` |
| `CompressMemToFile` | method | `public bool CompressMemToFile(byte[] inData, string toPath);` |
| `LoadTaskCaller` | method | `public bool LoadTaskCaller(Task task);` |
| `UncompressBd` | method | `public bool UncompressBd(BinData bd);` |
| `UncompressFile` | method | `public bool UncompressFile(string inFilename, string toPath);` |
| `UncompressFileToMem` | method | `public byte[] UncompressFileToMem(string inFilename);` |
| `UncompressMemory` | method | `public byte[] UncompressMemory(byte[] inData);` |
| `UncompressMemToFile` | method | `public bool UncompressMemToFile(byte[] inData, string toPath);` |

## Properties

### Bz2.AbortCurrent

`Chilkat 11.7.0 · csharp · Bz2 · AbortCurrent · property · read/write · since 9.5.0.58`

```csharp
public bool AbortCurrent {get; set; }
```

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.

### Bz2.HeartbeatMs

`Chilkat 11.7.0 · csharp · Bz2 · HeartbeatMs · property · read/write`

```csharp
public int HeartbeatMs {get; set; }
```

**Full documentation for this property (same in every language):** [Event Callback Examples](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/event_callback_examples.md)

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`.

## Methods

### Bz2.CompressBd

`Chilkat 11.7.0 · csharp · Bz2 · CompressBd · method · since 11.0.0`

```csharp
public bool CompressBd(BinData bd);
```

Compresses the current contents of `bd` 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.

Async variant: `CompressBdAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.CompressFile

`Chilkat 11.7.0 · csharp · Bz2 · CompressFile · method`

```csharp
public bool CompressFile(string inFilename, string toPath);
```

Reads the file at `inFilename` 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.

Async variant: `CompressFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.CompressFileToMem

`Chilkat 11.7.0 · csharp · Bz2 · CompressFileToMem · method`

```csharp
public byte[] CompressFileToMem(string inFilename);
```

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

Returns an empty byte array on failure

Async variant: `CompressFileToMemAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.CompressMemory

`Chilkat 11.7.0 · csharp · Bz2 · CompressMemory · method`

```csharp
public byte[] CompressMemory(byte[] inData);
```

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

Returns an empty byte array on failure

Async variant: `CompressMemoryAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.CompressMemToFile

`Chilkat 11.7.0 · csharp · Bz2 · CompressMemToFile · method`

```csharp
public bool CompressMemToFile(byte[] inData, string toPath);
```

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

Returns true for success, false for failure.

Async variant: `CompressMemToFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.LoadTaskCaller

`Chilkat 11.7.0 · csharp · Bz2 · LoadTaskCaller · method · since 9.5.0.80`

```csharp
public bool LoadTaskCaller(Task task);
```

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

**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.

### Bz2.UncompressBd

`Chilkat 11.7.0 · csharp · Bz2 · UncompressBd · method · since 11.0.0`

```csharp
public bool UncompressBd(BinData bd);
```

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

**Input requirement:** `bd` 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.

Async variant: `UncompressBdAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.UncompressFile

`Chilkat 11.7.0 · csharp · Bz2 · UncompressFile · method`

```csharp
public bool UncompressFile(string inFilename, string toPath);
```

Reads the BZip2 stream from the file at `inFilename`, 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.

Async variant: `UncompressFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.UncompressFileToMem

`Chilkat 11.7.0 · csharp · Bz2 · UncompressFileToMem · method`

```csharp
public byte[] UncompressFileToMem(string inFilename);
```

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

Returns an empty byte array on failure

Async variant: `UncompressFileToMemAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.UncompressMemory

`Chilkat 11.7.0 · csharp · Bz2 · UncompressMemory · method`

```csharp
public byte[] UncompressMemory(byte[] inData);
```

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

Returns an empty byte array on failure

Async variant: `UncompressMemoryAsync` — same arguments, returns a `Task` (see Async variants below).

### Bz2.UncompressMemToFile

`Chilkat 11.7.0 · csharp · Bz2 · UncompressMemToFile · method`

```csharp
public bool UncompressMemToFile(byte[] inData, string toPath);
```

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

Returns true for success, false for failure.

Async variant: `UncompressMemToFileAsync` — same arguments, returns a `Task` (see Async variants below).

## Events and callbacks

### Bz2.AbortCheck (event)

`Chilkat 11.7.0 · csharp · Bz2 · AbortCheck · event`

```csharp
public event AbortCheckEventHandler OnAbortCheck;
```

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.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.AbortCheckEventArgs

**Event callback implementation:**

```csharp
private void bz_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
bz.OnAbortCheck += bz_OnAbortCheck;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleAbortCheck(out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
// ...
Chilkat.Bz2.AbortCheck abortCheck = new Chilkat.Bz2.AbortCheck(handleAbortCheck);
bz.setAbortCheckCb(abortCheck);
```

### Bz2.PercentDone (event)

`Chilkat 11.7.0 · csharp · Bz2 · PercentDone · event`

```csharp
public event PercentDoneEventHandler OnPercentDone;
```

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 `pctDone` 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 `pctDone` 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.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.PercentDoneEventArgs

**Event callback implementation:**

```csharp
private void bz_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
bz.OnPercentDone += bz_OnPercentDone;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handlePercentDone(int pctDone, out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
// ...
Chilkat.Bz2.PercentDone percentDone = new Chilkat.Bz2.PercentDone(handlePercentDone);
bz.setPercentDoneCb(percentDone);
```

### Bz2.ProgressInfo (event)

`Chilkat 11.7.0 · csharp · Bz2 · ProgressInfo · event`

```csharp
public event ProgressInfoEventHandler OnProgressInfo;
```

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.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.ProgressInfoEventArgs

**Event callback implementation:**

```csharp
private void bz_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
bz.OnProgressInfo += bz_OnProgressInfo;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleProgressInfo(string name, string value)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
// ...
Chilkat.Bz2.ProgressInfo progressInfo = new Chilkat.Bz2.ProgressInfo(handleProgressInfo);
bz.setProgressInfoCb(progressInfo);
```

### Bz2.TaskCompleted (event)

`Chilkat 11.7.0 · csharp · Bz2 · TaskCompleted · event`

```csharp
public event TaskCompletedEventHandler OnTaskCompleted;
```

Called from the background thread when an asynchronous task completes.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.TaskCompletedEventArgs

**Event callback implementation:**

```csharp
private void bz_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
bz.OnTaskCompleted += bz_OnTaskCompleted;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleTaskIdCompleted(int taskId)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Bz2 bz = new Chilkat.Bz2();
// ...
Chilkat.Bz2.TaskIdCompleted taskIdCompleted = new Chilkat.Bz2.TaskIdCompleted(handleTaskIdCompleted);
bz.setTaskIdCompletedCb(taskIdCompleted);
```

## Async variants

Each returns a `Task` instead of the result and takes the same arguments as the synchronous method; run the task, wait for `Finished`, then read the result from the task. No new Async methods are added from 11.7.0 on.

```csharp
public Task CompressBdAsync(BinData bd);
public Task CompressFileAsync(string inFilename, string toPath);
public Task CompressFileToMemAsync(string inFilename);
public Task CompressMemoryAsync(byte[] inData);
public Task CompressMemToFileAsync(byte[] inData, string toPath);
public Task UncompressBdAsync(BinData bd);
public Task UncompressFileAsync(string inFilename, string toPath);
public Task UncompressFileToMemAsync(string inFilename);
public Task UncompressMemoryAsync(byte[] inData);
public Task UncompressMemToFileAsync(byte[] inData, string toPath);
```

## Related classes

[`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/BinData.md), [`Task`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/Task.md)