Symbian 压缩和解压缩GZIP文件

最新推荐文章于 2022-11-06 20:29:03 发布

程序员丹尼尔

最新推荐文章于 2022-11-06 20:29:03 发布

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分类专栏： Symbian General 文章标签： symbian user output file input buffer

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本文介绍了一种在S60 3rd Edition FP1平台上使用CEZFileToGZip和CEZGZipToFile类进行GZIP文件压缩和解压缩的方法。提供了自签名执行的代码示例，并通过命令行参数实现压缩或解压缩功能。

(Difference between revisions)
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
}