Symbian 压缩和解压缩GZIP文件

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Bogdan.galiceanu (Talk | contribs)
________________________________________
Current revision as of 16:15, 4 August 2009
CS000949

? 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
LIBRARY efsrv.lib
LIBRARY ezlib.lib

源文件
#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
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
  }