symbian压缩和解压缩GZIP文件

开发伙伴平台：
S60 3rd Edition, FP1

详细描述
下列代码片段演示了如何压缩和解压缩GZIP文件，这里使用了CEZFileToGZip类和CEZGZipToFi类。代码可以通过自签名执行。

MMP文件
需要下列链接库

Code:

LIBRARY efsrv.lib

LIBRARY ezlib.lib

源文件

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
下面这个示例演示了通过读取命令行参数来压缩或解压缩.gz文件

选项：
* -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

  }