TUnixCompress Delphi ActiveX Reference Documentation

TUnixCompress

UNIX (.Z) compression component.

Importing the Chilkat ActiveX into Delphi

Important: Whenever upgrading to a new version of Chilkat, make sure to re-imported ActiveX DLL into Delphi to regenerate the files described below.

Two things are required to use an ActiveX in Delphi:

  1. The ActiveX DLL needs to be registered via regsvr32 on the system where the Delphi application runs. See How To Register ActiveX DLLs for detailed information.
  2. The ActiveX component needs to be "imported". Use the Delphi Import Component Wizard to import the Chilkat type library. This creates the following files: Chilkat_v9_5_0_TLB.pas and Chilkat_v9_5_0_TLB.dcr. The Chilkat_v9_5_0_TLB.pas should be added to your project.

To import the Chilkat type library, do the following:

  1. In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
  2. Find "Chilkat ActiveX v9.5.0" in the list and select it. This will only appear in the list if the ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll) has been registered w/ regsvr32.
  3. Check the "Generate Component Wrappers" checkbox.
  4. Select a directory where the unit files (.pas and .dcr) will be generated.
  5. Select "Create Unit" and then "Finish".
  6. Add the .pas to your Delphi project.

To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_v9_5_0_TLB" to the "uses" statement. For example:

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_v9_5_0_TLB;

Object Creation

var
obj: TUnixCompress;
...
begin
obj := TUnixCompress.Create(Self);
...
// When finished, free the object instance.
obj.Free();

Properties

property AbortCurrent: Integer

Introduced in version 9.5.0.58

When set to 1, 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 0 when the next method is called. When the abort occurs, this property is reset to 0. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

property DebugLogFilePath: WideString

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.

property HeartbeatMs: Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

property LastBinaryResult: OleVariant readonly

Introduced in version 9.5.0.52

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to 1. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

property LastErrorHtml: WideString readonly

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.

property LastErrorText: WideString readonly

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.

property LastErrorXml: WideString readonly

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.

property LastMethodSuccess: Integer

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 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 = 1 and failure = 0.
  • 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 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

property LastStringResult: WideString readonly

Introduced in version 9.5.0.52

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to 1. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

Long Strings Returned by ActiveX Methods in SQL Server

property LastStringResultLen: Integer readonly

Introduced in version 9.5.0.53

The length, in characters, of the string contained in the LastStringResult property.

property VerboseLogging: Integer

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

property Version: WideString readonly

Version of the component/library, such as "9.4.1.42"

Methods

function CompressFile(inFilename: WideString; destPath: WideString): Integer;

Compresses a file to create a UNIX compressed file (.Z). This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.

Returns 1 for success, 0 for failure.

function CompressFileAsync(inFilename: WideString; destPath: WideString): TChilkatTask;

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.

How to Run an Asynchronous Task

function CompressFileToMem(inFilename: WideString): OleVariant;

Unix compresses a file to an in-memory image of a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

function CompressFileToMemAsync(inFilename: WideString): TChilkatTask;

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.

How to Run an Asynchronous Task

function CompressMemToFile(inData: OleVariant; destPath: WideString): Integer;

Unix compresses and creates a .Z file from in-memory data. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns 1 for success, 0 for failure.

function CompressMemory(inData: OleVariant): OleVariant;

Compresses in-memory data to an in-memory image of a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

function CompressString(inStr: WideString; charset: WideString): OleVariant;

Compresses a string to an in-memory image of a .Z file. Prior to compression, the string is converted to the character encoding specified by charset. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

List of Valid Charsets

function CompressStringToFile(inStr: WideString; charset: WideString; destPath: WideString): Integer;

Unix compresses and creates a .Z file from string data. The charset specifies the character encoding used for the byte representation of the characters when compressed. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns 1 for success, 0 for failure.

List of Valid Charsets

function IsUnlocked(): Integer;

Returns true if the component has been unlocked. (For ActiveX, returns 1 if unlocked.)

function ReadFile(filename: WideString): OleVariant;

Convenience method to read an entire file and return as a byte array.

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

function UnTarZ(zFilename: WideString; destDir: WideString; bNoAbsolute: Integer): Integer;

Unpacks a .tar.Z file. The decompress and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring.

Returns 1 for success, 0 for failure.

function UnTarZAsync(zFilename: WideString; destDir: WideString; bNoAbsolute: Integer): TChilkatTask;

Creates an asynchronous task to call the UnTarZ 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.

How to Run an Asynchronous Task

function UncompressFile(inFilename: WideString; destPath: WideString): Integer;

Uncompresses a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns 1 for success, 0 for failure.

function UncompressFileAsync(inFilename: WideString; destPath: WideString): TChilkatTask;

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.

How to Run an Asynchronous Task

function UncompressFileToMem(inFilename: WideString): OleVariant;

Uncompresses a .Z file directly to memory. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

function UncompressFileToMemAsync(inFilename: WideString): TChilkatTask;

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.

How to Run an Asynchronous Task

function UncompressFileToString(zFilename: WideString; charset: WideString): WideString;

Uncompresses a .Z file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by charset. Typical charsets are "iso-8859-1", "utf-8", "windows-1252", "shift_JIS", "big5", etc.

Returns a zero-length WideString on failure

List of Valid Charsets

function UncompressFileToStringAsync(zFilename: WideString; charset: WideString): TChilkatTask;

Creates an asynchronous task to call the UncompressFileToString 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.

How to Run an Asynchronous Task

function UncompressMemToFile(inData: OleVariant; destPath: WideString): Integer;

Uncompresses from an in-memory image of a .Z file to a file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns 1 for success, 0 for failure.

function UncompressMemory(inData: OleVariant): OleVariant;

Uncompresses from an in-memory image of a .Z file directly into memory. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.

function UncompressString(inCompressedData: OleVariant; charset: WideString): WideString;

Uncompresses from an in-memory image of a .Z file directly to a string. The charset specifies the character encoding used to interpret the bytes resulting from the decompression. The charset can be any one of a large number of character encodings, such as "utf-8", "iso-8859-1", "Windows-1252", "ucs-2", etc.

Returns a zero-length WideString on failure

List of Valid Charsets

function UnlockComponent(unlockCode: WideString): Integer;

Unlocks the component allowing for the full functionality to be used.

Returns 1 for success, 0 for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Permanent Unlock Code

LastErrorText Standard Information

function WriteFile(filename: WideString; binaryData: OleVariant): Integer;

Convenience method for writing the contents of a byte array to a file.

Returns 1 for success, 0 for failure.

Events

procedure AbortCheck(ASender: TObject; out abort: Integer);

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.

Delphi ActiveX Event callback implementation:

procedure TForm1.unixcompressAbortCheck(ASender: TObject;  out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  unixcompress: TUnixCompress;

begin
  unixcompress := TUnixCompress.Create(Self);
  unixcompress.OnAbortCheck := unixcompressAbortCheck;
  // ...

procedure PercentDone(ASender: TObject; pctDone: Integer; out abort: Integer);

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.

The abort output argument provides a means for aborting the operation. Setting it to 1 will cause the method to abort and return a failed status (or whatever return value indicates failure).

Delphi ActiveX Event callback implementation:

procedure TForm1.unixcompressPercentDone(ASender: TObject;  pctDone: Integer; out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  unixcompress: TUnixCompress;

begin
  unixcompress := TUnixCompress.Create(Self);
  unixcompress.OnPercentDone := unixcompressPercentDone;
  // ...