Bz2 Delphi DLL Reference Documentation

Bz2

Current Version: 9.5.0.88

Provides the ability to create and unzip .bz2 compressed files using the BZip2 compression algorithm.

Create/Dispose

var
myObject: HCkBz2;

begin
myObject := CkBz2_Create();

// ...

CkBz2_Dispose(myObject);
end;
function CkBz2_Create: HCkBz2; stdcall;

Creates an instance of the HCkBz2 object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.

procedure CkBz2_Dispose(handle: HCkBz2); stdcall;

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.

Properties

AbortCurrent
function CkBz2_getAbortCurrent(objHandle: HCkBz2): wordbool; stdcall;
procedure CkBz2_putAbortCurrent(objHandle: HCkBz2; newPropVal: wordbool); stdcall;
Introduced in version 9.5.0.58

When set to True, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to False when the next method is called. When the abort occurs, this property is reset to False. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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DebugLogFilePath
procedure CkBz2_getDebugLogFilePath(objHandle: HCkBz2; outPropVal: HCkString); stdcall;
procedure CkBz2_putDebugLogFilePath(objHandle: HCkBz2; newPropVal: PWideChar); stdcall;
function CkBz2__debugLogFilePath(objHandle: HCkBz2): PWideChar; stdcall;

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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HeartbeatMs
function CkBz2_getHeartbeatMs(objHandle: HCkBz2): Integer; stdcall;
procedure CkBz2_putHeartbeatMs(objHandle: HCkBz2; newPropVal: Integer); stdcall;

This is the number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any compress or decompress operation prior to completion. If HeartbeatMs is 0, no AbortCheck event callbacks will occur.

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LastErrorHtml
procedure CkBz2_getLastErrorHtml(objHandle: HCkBz2; outPropVal: HCkString); stdcall;
function CkBz2__lastErrorHtml(objHandle: HCkBz2): PWideChar; stdcall;

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
procedure CkBz2_getLastErrorText(objHandle: HCkBz2; outPropVal: HCkString); stdcall;
function CkBz2__lastErrorText(objHandle: HCkBz2): PWideChar; stdcall;

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
procedure CkBz2_getLastErrorXml(objHandle: HCkBz2; outPropVal: HCkString); stdcall;
function CkBz2__lastErrorXml(objHandle: HCkBz2): PWideChar; stdcall;

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
function CkBz2_getLastMethodSuccess(objHandle: HCkBz2): wordbool; stdcall;
procedure CkBz2_putLastMethodSuccess(objHandle: HCkBz2; newPropVal: wordbool); stdcall;
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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VerboseLogging
function CkBz2_getVerboseLogging(objHandle: HCkBz2): wordbool; stdcall;
procedure CkBz2_putVerboseLogging(objHandle: HCkBz2; newPropVal: wordbool); stdcall;

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.

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Version
procedure CkBz2_getVersion(objHandle: HCkBz2; outPropVal: HCkString); stdcall;
function CkBz2__version(objHandle: HCkBz2): PWideChar; stdcall;

Version of the component/library, such as "9.5.0.63"

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Methods

CompressFile
function CkBz2_CompressFile(objHandle: HCkBz2;
    inFilename: PWideChar;
    toPath: PWideChar): wordbool; stdcall;

Compresses a file to create a BZip2 compressed file (.bz2).

Note: Both inFilename and toPath should be relative or absolute file paths (not just a path to a directory). For example "someDir1/someDir2/myFile.txt" or "c:/someDir1/myFile.bz2".

Returns True for success, False for failure.

More Information and Examples
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CompressFileAsync (1)
function CkBz2_CompressFileAsync(objHandle: HCkBz2;
    inFilename: PWideChar;
    toPath: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the CompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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CompressFileToMem
function CkBz2_CompressFileToMem(objHandle: HCkBz2;
    inFilename: PWideChar;
    outBytes: HCkByteData): wordbool; stdcall;

BZip2 compresses a file to an in-memory image of a .bz2 file.

Returns True for success, False for failure.

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CompressFileToMemAsync (1)
function CkBz2_CompressFileToMemAsync(objHandle: HCkBz2;
    inFilename: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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CompressMemory
function CkBz2_CompressMemory(objHandle: HCkBz2;
    inData: HCkByteData;
    outBytes: HCkByteData): wordbool; stdcall;

Compresses in-memory data to an in-memory image of a .bz2 file.

Returns True for success, False for failure.

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CompressMemoryAsync (1)
function CkBz2_CompressMemoryAsync(objHandle: HCkBz2;
    inData: HCkByteData): HCkTask; stdcall;

Creates an asynchronous task to call the CompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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CompressMemToFile
function CkBz2_CompressMemToFile(objHandle: HCkBz2;
    inData: HCkByteData;
    toPath: PWideChar): wordbool; stdcall;

BZip2 compresses and creates a .bz2 file from in-memory data.

Returns True for success, False for failure.

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CompressMemToFileAsync (1)
function CkBz2_CompressMemToFileAsync(objHandle: HCkBz2;
    inData: HCkByteData;
    toPath: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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LoadTaskCaller
function CkBz2_LoadTaskCaller(objHandle: HCkBz2;
    task: HCkTask): wordbool; stdcall;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

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UncompressFile
function CkBz2_UncompressFile(objHandle: HCkBz2;
    inFilename: PWideChar;
    toPath: PWideChar): wordbool; stdcall;

Unzips a .bz2 file.

Returns True for success, False for failure.

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UncompressFileAsync (1)
function CkBz2_UncompressFileAsync(objHandle: HCkBz2;
    inFilename: PWideChar;
    toPath: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the UncompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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UncompressFileToMem
function CkBz2_UncompressFileToMem(objHandle: HCkBz2;
    inFilename: PWideChar;
    outBytes: HCkByteData): wordbool; stdcall;

Unzips a .bz2 file directly to memory.

Returns True for success, False for failure.

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UncompressFileToMemAsync (1)
function CkBz2_UncompressFileToMemAsync(objHandle: HCkBz2;
    inFilename: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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UncompressMemory
function CkBz2_UncompressMemory(objHandle: HCkBz2;
    inData: HCkByteData;
    outBytes: HCkByteData): wordbool; stdcall;

Unzips from an in-memory image of a .bz2 file directly into memory.

Returns True for success, False for failure.

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UncompressMemoryAsync (1)
function CkBz2_UncompressMemoryAsync(objHandle: HCkBz2;
    inData: HCkByteData): HCkTask; stdcall;

Creates an asynchronous task to call the UncompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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UncompressMemToFile
function CkBz2_UncompressMemToFile(objHandle: HCkBz2;
    inData: HCkByteData;
    toPath: PWideChar): wordbool; stdcall;

Unzips from an in-memory image of a .bz2 file to a file.

Returns True for success, False for failure.

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UncompressMemToFileAsync (1)
function CkBz2_UncompressMemToFileAsync(objHandle: HCkBz2;
    inData: HCkByteData;
    toPath: PWideChar): HCkTask; stdcall;

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

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

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Events

Chilkat supports event callbacks for the Delphi DLL starting in version 9.5.0.82.

AbortCheck
function MyAbortCheck(): Integer; cdecl;
Introduced in version 9.5.0.82

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200. Return True to abort; return False to continue (not abort)

More Information and Examples
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PercentDone
function MyPercentDone(pctDone: Integer): Integer; cdecl;
Introduced in version 9.5.0.82

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 event is only fired 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 operations (Chilkat method calls) 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).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

Return True to abort; return False to continue (not abort)

More Information and Examples
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ProgressInfo
procedure MyProgressInfo(name: PWideChar; value: PWideChar) cdecl;
Introduced in version 9.5.0.82

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

More Information and Examples
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TaskCompleted
procedure MyTaskCompleted(task: HCkTask) cdecl;
Introduced in version 9.5.0.82

Called in the background thread when an asynchronous task completes.

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