symbian壓縮和解壓縮GZIP檔案

開發夥伴平台：
S60 3rd Edition, FP1

詳細描述
下列程式碼片段示範了如何壓縮和解壓縮GZIP檔案，這裡使用了CEZFileToGZip類和CEZGZipToFi類。代碼可以通過自簽名執行。

MMP檔案
需要下列連結庫

Code:

LIBRARY efsrv.lib
LIBRARY ezlib.lib

源檔案

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
}

使用CompressGZipFileL()和DecompressGZipFileL()方法
下面這個樣本示範了通過讀取命令列參數來壓縮或解壓縮.gz檔案

選項：
* -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
  }