Bz2 C Reference Documentation
Bz2
Current Version: 11.5.0
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
Create/Dispose
HCkBz2 instance = CkBz2_Create(); // ... CkBz2_Dispose(instance);
Creates an instance of the HCkBz2 object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkBz2_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkBz2_Dispose.
Callback Functions
Provides the opportunity for a method call to be aborted. If TRUE is returned, the operation in progress is aborted.
Return FALSE to allow the current method call to continue.
This callback function is called periodically based on the value of the HeartbeatMs property.
(If HeartbeatMs is 0, then no callbacks are made.) As an example, to make 5 AbortCheck callbacks per second, set the HeartbeatMs property equal to 200.
See Also:C Example using Callback Functions
Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This callback is only called when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For methods that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).
This callback counts as an AbortCheck callback, and takes the place of the AbortCheck event when it fires.
The return value indicates whether the method call should be aborted, or whether it should proceed. Return TRUE to abort, and FALSE to proceed.
This is a general callback that provides name/value information about what is happening at certain points during a method call. To see the information provided in ProgressInfo callbacks, if any, write code to handle this event and log the name/value pairs. Most are self-explanatory.
Called in the background thread when an asynchronous task completes. (Note: When an async method is running, all callbacks are in the background thread.)
Properties
AbortCurrent
void CkBz2_putAbortCurrent(HCkBz2 cHandle, BOOL newVal);
Set this property to TRUE
A synchronous call can be cancelled by setting this property from another thread. After cancellation is processed, Chilkat resets the property to FALSE
LastErrorText to determine the final outcome.DebugLogFilePath
void CkBz2_putDebugLogFilePath(HCkBz2 cHandle, const char *newVal);
const char *CkBz2_debugLogFilePath(HCkBz2 cHandle);
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.
HeartbeatMs
void CkBz2_putHeartbeatMs(HCkBz2 cHandle, int newVal);
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.
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 TRUELastErrorHtml
const char *CkBz2_lastErrorHtml(HCkBz2 cHandle);
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.
topLastErrorText
const char *CkBz2_lastErrorText(HCkBz2 cHandle);
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.
LastErrorXml
const char *CkBz2_lastErrorXml(HCkBz2 cHandle);
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.
topLastMethodSuccess
void CkBz2_putLastMethodSuccess(HCkBz2 cHandle, BOOL newVal);
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.
Utf8
void CkBz2_putUtf8(HCkBz2 cHandle, BOOL newVal);
When set to TRUE, all const char * arguments and return values are interpreted as UTF-8 strings. When set to FALSE, they are interpreted as ANSI strings.
In Chilkat v11.0.0 and later, the default value is TRUE. Before v11.0.0, it was FALSE.
VerboseLogging
void CkBz2_putVerboseLogging(HCkBz2 cHandle, BOOL newVal);
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
Methods
CompressBd
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.
Returns TRUE for success, FALSE for failure.
topCompressBdAsync (1)
Creates an asynchronous task to call the CompressBd method with the arguments provided.
Returns NULL on failure
CompressFile
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.
.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.
CompressFileAsync (1)
Creates an asynchronous task to call the CompressFile method with the arguments provided.
Returns NULL on failure
LoadTaskCaller
Loads this Bz2 object with the caller state associated with the asynchronous operation represented by task.
Task created by a compatible Bz2 asynchronous method; an unrelated task cannot be loaded.Returns TRUE for success, FALSE for failure.
topUncompressBd
Decompresses the BZip2 stream currently contained in bd in place. On success, the BinData is replaced with the original uncompressed bytes.
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.
topUncompressBdAsync (1)
Creates an asynchronous task to call the UncompressBd method with the arguments provided.
Returns NULL on failure
UncompressFile
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.
.bz2 file normally contains a single compressed byte stream rather than a collection of named files.Returns TRUE for success, FALSE for failure.
topUncompressFileAsync (1)
Creates an asynchronous task to call the UncompressFile method with the arguments provided.
Returns NULL on failure
Deprecated
CompressFileToMem Deprecated
Reads the file at inFilename, compresses it with BZip2, and returns the complete .bz2 byte stream in memory.
Returns TRUE for success, FALSE for failure.
topCompressFileToMemAsync Deprecated (1)
Creates an asynchronous task to call the CompressFileToMem method with the arguments provided.
Returns NULL on failure
CompressMemory Deprecated
Compresses the bytes in inData and returns the complete standard BZip2 stream as an in-memory byte array.
Returns TRUE for success, FALSE for failure.
topCompressMemoryAsync Deprecated (1)
Creates an asynchronous task to call the CompressMemory method with the arguments provided.
Returns NULL on failure
CompressMemToFile Deprecated
Compresses the bytes in inData and writes the resulting standard BZip2 stream to the file at toPath.
Returns TRUE for success, FALSE for failure.
topCompressMemToFileAsync Deprecated (1)
Creates an asynchronous task to call the CompressMemToFile method with the arguments provided.
Returns NULL on failure
UncompressFileToMem Deprecated
Reads and decompresses the BZip2 stream in the file at inFilename, returning the original uncompressed bytes in memory.
Returns TRUE for success, FALSE for failure.
topUncompressFileToMemAsync Deprecated (1)
Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided.
Returns NULL on failure
UncompressMemory Deprecated
Interprets inData as a complete BZip2 stream and returns the decompressed bytes in memory.
Returns TRUE for success, FALSE for failure.
topUncompressMemoryAsync Deprecated (1)
Creates an asynchronous task to call the UncompressMemory method with the arguments provided.
Returns NULL on failure
UncompressMemToFile Deprecated
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.
topUncompressMemToFileAsync Deprecated (1)
Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided.
Returns NULL on failure