Compress and decompress the GZIP file in Symbian.

Development partner platform:
S60 3rd edition, FP1

Detailed description
The following code snippet demonstrates how to compress and decompress the GZIP file. The cezfiletogzip class and cezgziptofi class are used here. The code can be executed through self-signature.

MPs File
The following link library is required

Code:

LIBRARY efsrv.lib
LIBRARY ezlib.lib

Source File

Code:

#include <ezgzip.h>
#include <f32file.h>

void CompressGZipFileL(RFs &aFs, TInt aBufferSize, const TDesC& aFileName)
{
   RFile input;

   HBufC *compressedFile = HBufC::NewLC(aFileName.Length()+3);
  _LIT(KCompressedGZipFileName,"%S.gz");
  compressedFile->Des().Format(KCompressedGZipFileName,&aFileName);

  User::LeaveIfError(input.Open(aFs,aFileName,EFileStream | EFileRead | EFileShareAny));
  CleanupClosePushL(input);

  CEZFileToGZip *fileToGZip = CEZFileToGZip::NewLC(aFs,*compressedFile,input,aBufferSize);

  _LIT(KCompressingToGZipFile,"Compressing file %S to gzip file %S/n");
  console->Printf(KCompressingToGZipFile,&aFileName,compressedFile);

  while (fileToGZip->DeflateL())
    {
    // loop here until the gzip file is created
    }

  CleanupStack::PopAndDestroy(3); //fileToGZip, input, compressedFile
}

void DecompressGZipFileL(RFs &aFs, TInt aBufferSize, const TDesC& aFileName)
{
  TInt err(KErrNone);
  RFile output;

  HBufC *decompressedFile = HBufC::NewLC(aFileName.Length()+1);
  _LIT(KDecompressedGZipFileName,"%S_");
  decompressedFile->Des().Format(KDecompressedGZipFileName,&aFileName);

  err = output.Create(aFs, *decompressedFile,EFileStream | EFileWrite |
 EFileShareExclusive);
  if (err == KErrAlreadyExists)
    User::LeaveIfError(output.Open(aFs, *decompressedFile,EFileStream |
 EFileWrite | EFileShareExclusive));
  else 
    User::LeaveIfError(err);
  CleanupClosePushL(output);

  CEZGZipToFile *gZipToFile = CEZGZipToFile::NewLC(aFs,aFileName,output,aBufferSize);

  _LIT(KDecompressingFromGZipFile,"Decompressing file %S from gzip file %S/n");
  console->Printf(KDecompressingFromGZipFile, decompressedFile, &aFileName);

  while (gZipToFile->InflateL())
    {
    // loop here until the gzip file is decompressed
    }

    CleanupStack::PopAndDestroy(3); //gZipToFile, output, decompressedFile
}

Use the compressgzipfilel () and decompressgzipfilel () Methods
The following example demonstrates how to use the command line to compress or decompress the. GZ file.

Option:
*-C = Compress
*-D = decompress
*-B n = buffer size
* Filename = GZIP file

Code:

void doGZipCompressionAndDecompressionL()
  {
  RFs fs;
  User::LeaveIfError(fs.Connect());
  CleanupClosePushL(fs);

  TBool doCompress = ETrue;
  TInt bufferSize = 32768;
  TInt cmdLineLen = User::CommandLineLength();

  if (cmdLineLen <= 0)
    {
    _LIT(KUsage,"Usage: program.exe [-cd] [-u buffer] filename/n");
    console->Printf(KUsage);
    User::Leave(KErrGeneral);
    }

  HBufC *argv = HBufC::NewLC(cmdLineLen);
  TPtr argPtr=argv->Des();
  User::CommandLine(argPtr);

  TLex arguments(*argv);

  TPtrC options(arguments.NextToken());
  TBool bufferSizeSpecified = EFalse;

  _LIT(KInvalidOption,"Invalid option %S/n");
  _LIT(KUnknownOption,"Unknown option %S/n");
  _LIT(KNoOptionSpecified,"No option specified/n");

  while (options[0]=='-' || bufferSizeSpecified)
    {
    TInt index = 1;

    if (bufferSizeSpecified)
      {
      if (options.Length() == 0)
        {
        console->Printf(KNoOptionSpecified);
        console->Getch();
        User::Leave(KErrGeneral);
        }
      else
        {
        TLex lex(options);
        TInt ret(KErrNone);         

       ret = lex.Val(bufferSize);
       bufferSizeSpecified = EFalse;

        if (ret != KErrNone)
          {
          console->Printf(KInvalidOption,&options);
          console->Getch();
          User::Leave(KErrGeneral);
          }
        }
      }
    else
      {        
      while (index < options.Length())
        {
        if (options[index] == 'd')
          doCompress = EFalse;
        else if (options[index] == 'c')
          doCompress = ETrue;
        else if (options[index] == 'b' )
         bufferSizeSpecified = ETrue;
        else 
          {
          console->Printf(KUnknownOption,&options);
          console->Getch();
          User::Leave(KErrGeneral);
          }
        index++;
        }

      if (index == 1)
        {        
        console->Printf(KNoOptionSpecified);
        console->Getch();
        User::Leave(KErrGeneral);
        }
      }
    options.Set(arguments.NextToken());
    }

    TPtrC fileNamePtr(options);
    HBufC *fileNameBuf = HBufC::NewLC(fileNamePtr.Length());
    *fileNameBuf = fileNamePtr;

    if(doCompress)
   CompressGZipFileL(fs,bufferSize,*fileNameBuf);
    else
   DecompressGZipFileL(fs,bufferSize,*fileNameBuf);

    CleanupStack::PopAndDestroy(3); //fileNameBuf,argv,fs
  }