Zip::ZipStatFilter

Engine/source/core/util/zip/zipStatFilter.h

Helper class for tracking CRC and uncompressed size.

More...

FilterStream

Parent 

CentralDir *

mCD 

Stream *

mStream 

bool

_read(const U32 numBytes, void * buffer)

bool

_write(const U32 numBytes, const void * buffer)

ZipStatFilter()

ZipStatFilter(CentralDir * cd)

~ZipStatFilter()

bool

attachStream(Stream * stream)

void

detachStream()

CentralDir *

getCentralDir()

Stream *

getStream()

void

setCentralDir(CentralDir * cd)

Detailed Description

Helper class for tracking CRC and uncompressed size.

ZipStatFilter allows us to track CRC and uncompressed size on the fly. This is necessary when dealing with compressed files as the CRC must be of the uncompressed data.

ZipStatFilter is mostly intended for internal use by the zip code. However, it can be useful when reading zips sequentially using the stream interface to provide CRC checking.

Example

// It's assumed that you would use proper error checking and that
// zip is a valid pointer to a ZipArchive and otherStream is a pointer
// to a valid stream.
Zip::ZipArchive *zip;
Stream *otherStream;

// We need the real central directory to compare the CRC32
Zip::CentralDir *realCD = zip->findFileInfo("file.txt");
Stream *stream = zip->openFile("file.txt", ZipArchive::Read);

Zip::CentralDir fakeCD;
Zip::ZipStatFilter zsf(&fakeCD);

zsf.attachStream(stream);

// ... read <i>entire</i> file sequentially using zsf instead of stream
otherStream->copyFrom(&zsf);

zsf.detachStream();

// fakeCD.mCRC32 now contains the CRC32 of the stream
if(fakeCD.mCRC32 != realCD->mCRC32)
{
   // ... handle CRC failure ...
}

zip->closeFile(stream);

A more complete example of this may be found in the code for the ZipArchive::extractFile() method in zipArchive.cc

typedef FilterStream Parent 

CentralDir * mCD 

Stream * mStream 

_read(const U32 numBytes, void * buffer)

_write(const U32 numBytes, const void * buffer)

ZipStatFilter()

ZipStatFilter(CentralDir * cd)

~ZipStatFilter()

attachStream(Stream * stream)

detachStream()

getCentralDir()

getStream()

setCentralDir(CentralDir * cd)