bzip2lib

About

bzip2lib provides stream classes for bzip2 compression and decompression.

Unit bzip2lib contains 2 stream classes for BZIP2 compression and decompression:

• TBzip2CompressStream for compressing (packing) data to bzip2 format.
• TBzip2DecompressStream for decompressing (unpacking) data back to its original form.

Unit bzip2lib is collected and edited from 2 unit files in Jcl package:

• JclCompression
• bzip2

The purpose was to make it compile and work with FPC (Free Pascal Compiler). In the process lots of code with conditional compilation directives were removed and also many unit dependencies were removed.

The download contains the source unit file and a demo program which compresses and then again decompresses a text file given as a command line parameter.

Author

Juha Manninen <juha dot manninen (at) phnet dot fi>

   + the original authors from Jcl code.

License

This code is licensed under the same terms as Jcl library.

Download

The latest stable release can be found on link to the lazarus-ccr sf download location.

Change Log

• Version 1.0, Date: 2009.11.06

Dependencies / System Requirements

• None

Status: Stable

Issues:

Dependencies

The code uses external bzip2 libraries for its job:

 'bzip2.dll' in Windows
 'libbz2.so.1' in Linux

Usage

Just include unit bzip2lib in the "uses" section. External bzip2 library must be installed in your machine (see *Dependencies*). Use TBzip2CompressStream and TBzip2DecompressStream just like any stream, connecting them to file stream or memory stream if needed.

Example code for bzip2lib

• Compressing a string to a file. "S" is the string to compress.

<Delphi>

 OutFileStream := TFileStream.Create(CompressedFileName, fmCreate);
 try
   CompressStream := TBzip2CompressStream.Create(OutFileStream);
   try
     CompressStream.Write(Pointer(S)^, Length(S));
   finally
     CompressStream.Free;
   end;
 finally
   OutFileStream.Free;
 end;

</Delphi>

• Decompressing from a file to a TStringList. TStringList.LoadFromStream can be used here.

<Delphi>

 InFileStream := TFileStream.Create(CompressedFileName, fmOpenRead);
 DecompressStream := TBzip2DecompressStream.Create(InFileStream);
 try
   SL.Clear;
   SL.LoadFromStream(DecompressStream);
   SL.SaveToFile(OutFileName);
 finally
   InFileStream.Free;
 end;

</Delphi>