--- product: Chilkat product_version: 11.7.0 language: cpp language_label: C++ class: Bz2 class_name: CkBz2 license: bundle deprecated: false reference_html: https://www.chilkatsoft.com/refdoc/vcCkBz2Ref.html --- # Chilkat Bz2 — C++ — v11.7.0 > Chilkat 11.7.0 · language=cpp · class=Bz2 (CkBz2) > Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0//classes/Bz2.md`. > Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/cpp/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** ```cpp // Local variable on the stack CkBz2 obj; // Dynamically allocate/delete CkBz2 *pObj = new CkBz2(); // ... delete pObj; ``` 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++. 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` | `void get_DebugLogFilePath(CkString &str); const char *debugLogFilePath(void); void put_DebugLogFilePath(const char *newVal);` | 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` | `void get_LastErrorHtml(CkString &str); const char *lastErrorHtml(void);` | read-only | Provides HTML-formatted information about the last called method or property. | | `LastErrorText` | `void get_LastErrorText(CkString &str); const char *lastErrorText(void);` | read-only | Provides plain text information about the last called method or property. | | `LastErrorXml` | `void get_LastErrorXml(CkString &str); const char *lastErrorXml(void);` | read-only | Provides XML-formatted information about the last called method or property. | | `LastMethodSuccess` | `bool get_LastMethodSuccess(void); void put_LastMethodSuccess(bool newVal);` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. | | `Utf8` | `bool get_Utf8(void); void put_Utf8(bool newVal);` | read/write | When set to `true`, all `const char *` arguments and return values are interpreted as UTF-8 strings. | | `VerboseLogging` | `bool get_VerboseLogging(void); void put_VerboseLogging(bool newVal);` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. | | `Version` | `void get_Version(CkString &str); const char *version(void);` | read-only | Version of the component/library, such as "10.1.0" | ## Member index | Member | Kind | Signature | |---|---|---| | `AbortCurrent` | property, read/write | `bool get_AbortCurrent(void); void put_AbortCurrent(bool newVal);` | | `HeartbeatMs` | property, read/write | `int get_HeartbeatMs(void); void put_HeartbeatMs(int newVal);` | | `CompressBd` | method | `bool CompressBd(CkBinData &bd);` | | `CompressFile` | method | `bool CompressFile(const char *inFilename, const char *toPath);` | | `LoadTaskCaller` | method | `bool LoadTaskCaller(CkTask &task);` | | `UncompressBd` | method | `bool UncompressBd(CkBinData &bd);` | | `UncompressFile` | method | `bool UncompressFile(const char *inFilename, const char *toPath);` | Deprecated members are listed at the end of this file with their replacements; do not use them in new code. ## Properties ### Bz2.AbortCurrent `Chilkat 11.7.0 · cpp · Bz2 · AbortCurrent · property · read/write · since 9.5.0.58` ```cpp bool get_AbortCurrent(void); void put_AbortCurrent(bool newVal); ``` 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 · cpp · Bz2 · HeartbeatMs · property · read/write` ```cpp int get_HeartbeatMs(void); void put_HeartbeatMs(int newVal); ``` **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 · cpp · Bz2 · CompressBd · method · since 11.0.0` ```cpp bool CompressBd(CkBinData &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 · cpp · Bz2 · CompressFile · method` ```cpp bool CompressFile(const char *inFilename, const char *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.LoadTaskCaller `Chilkat 11.7.0 · cpp · Bz2 · LoadTaskCaller · method · since 9.5.0.80` ```cpp bool LoadTaskCaller(CkTask &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 · cpp · Bz2 · UncompressBd · method · since 11.0.0` ```cpp bool UncompressBd(CkBinData &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 · cpp · Bz2 · UncompressFile · method` ```cpp bool UncompressFile(const char *inFilename, const char *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). ## Events and callbacks To implement an event callback, your application would define and implement a class that inherits from CkBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkBaseProgress base class. **For example:** ```cpp CkBz2 bz; MyBz2Progress callbackObj; bz.put_EventCallbackObject(&callbackObj); ``` **MyBz2Progress example:** ```cpp #include "CkBaseProgress.h" class MyBz2Progress : public CkBaseProgress { public: MyBz2Progress(); virtual ~MyBz2Progress(); void AbortCheck(bool *abort); void PercentDone(int pctDone, bool *abort); void ProgressInfo(const char *name, const char *value); void TaskCompleted(CkTask &task); }; ``` ### Bz2.AbortCheck (event) `Chilkat 11.7.0 · cpp · Bz2 · AbortCheck · event` ```cpp void AbortCheck(bool *abort); ``` 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. ### Bz2.PercentDone (event) `Chilkat 11.7.0 · cpp · Bz2 · PercentDone · event` ```cpp void PercentDone(int pctDone, bool *abort); ``` 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. ### Bz2.ProgressInfo (event) `Chilkat 11.7.0 · cpp · Bz2 · ProgressInfo · event` ```cpp void ProgressInfo(const char *name, const char *value); ``` 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. ### Bz2.TaskCompleted (event) `Chilkat 11.7.0 · cpp · Bz2 · TaskCompleted · event` ```cpp void TaskCompleted(CkTask &task); ``` Called from the background thread when an asynchronous task completes. ## 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. ```cpp CkTask *CompressBdAsync(CkBinData &bd); CkTask *CompressFileAsync(const char *inFilename, const char *toPath); CkTask *UncompressBdAsync(CkBinData &bd); CkTask *UncompressFileAsync(const char *inFilename, const char *toPath); ``` ## Deprecated members — do not use in new code | Member | Kind | Deprecated in | Use instead | |---|---|---|---| | `CompressFileToMem` | method | before 11.6.1 | — | | `CompressMemory` | method | before 11.6.1 | — | | `CompressMemToFile` | method | before 11.6.1 | — | | `UncompressFileToMem` | method | before 11.6.1 | — | | `UncompressMemory` | method | before 11.6.1 | — | | `UncompressMemToFile` | method | before 11.6.1 | — | ## Related classes [`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/cpp/classes/BinData.md), [`Task`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/cpp/classes/Task.md)