* extraction example by Reinier Olislagers. Mantis #21304

git-svn-id: trunk@21387 -

.gitattributes

@@ -1030,6 +1030,7 @@ packages/bzip2/LICENSE svneol=native#text/plain
 packages/bzip2/Makefile svneol=native#text/plain
 packages/bzip2/Makefile.fpc svneol=native#text/plain
 packages/bzip2/Makefile.fpc.fpcmake svneol=native#text/plain
+packages/bzip2/examples/pasbunzip2.pas svneol=native#text/plain
 packages/bzip2/examples/pasbzip.pas svneol=native#text/plain
 packages/bzip2/fpmake.pp svneol=native#text/plain
 packages/bzip2/src/bzip2.pas svneol=native#text/plain

packages/bzip2/examples/pasbunzip2.pas

@@ -0,0 +1,86 @@
+program pasbunzip2;
+{
+    This file is part of the Free Pascal packages.
+    Copyright (c) 2012 Reinier Olislagers
+
+    Tests bzip2 decompression.
+
+    See the file COPYING.FPC, included in this distribution,
+    for details about the copyright.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+ **********************************************************************}
+{$mode objfpc}{$H+}
+
+{ 
+Example .bz2 file extractor.
+Decompresses a .bz2 file into another file using the classes-based bzip2stream unit
+Usage: bunzip2 compressedfile.bz2
+}
+
+uses classes, bzip2stream;
+
+function Decompress(SourceFile, TargetFile: string): boolean;
+var
+  InFile:TFileStream;
+  Decompressed:TDecompressBzip2Stream;
+  OutFile:TFileStream;
+  Buffer: Pointer;
+  i: integer;
+const buffersize=$2000;
+begin
+  result:=false; //fail by default
+  InFile:=TFileStream.Create(SourceFile, fmOpenRead);
+  try
+    try
+      Decompressed:=TDecompressBzip2Stream.Create(InFile);
+    except      
+      // So[5mething went wrong, e.g. invalid format
+      // Now get out of function with result false
+      exit;
+    end;
+    OutFile:=TFileStream.Create(TargetFile, fmCreate);
+    try
+      //We don't have seek on the TDecompressBzip2stream, so can't use
+      //CopyFrom...
+      //Decompressed.CopyFrom(InFile, InFile.Size);
+      GetMem(Buffer,BufferSize);
+      repeat
+        i:=Decompressed.Read(buffer^,BufferSize);
+        if i>0 then
+          OutFile.WriteBuffer(buffer^,i);
+      until i<BufferSize;
+      result:=true;
+    finally
+      Decompressed.Free;
+      OutFile.Free;
+    end;
+  finally
+    InFile.Free;
+  end;
+end;
+
+var
+  CompressedFile:string;
+  DecompressedFile:string;
+begin
+  CompressedFile:=ParamStr(1);
+  if CompressedFile='' then
+  begin
+    writeln('Usage: '+ParamStr(0)+' <file>');
+    halt(13); // show error in exit code
+  end;
+  DecompressedFile:=CompressedFile+'.out';
+  if Decompress(CompressedFile, DecompressedFile) then
+  begin
+    writeln('Decompressed '+CompressedFile+' to '+DecompressedFile);
+  end
+  else
+  begin  
+    writeln('An error occurred while decompressing '+CompressedFile);
+    halt(1); // show error in exit code
+  end;
+end.