Inheritance diagram

Collaboration diagram

Description

The SFXZIPDecoder class is used to decompress the DEFLATE compressed data by gzip to be read from the SFBSource or SFBAStream instance or the storage such as SFXFile or SFXTCPSocket.

	Limitation
	Data can be read from the SFXZIPDecoder storage, but it cannot be written into this storage. The function to move the read pointer is not supported.

How to use the SFXZIPDecoder class

// _decoder is declared as class member variable since used the callback function
class MyClass {
private:
    SFXFile _file;                      // input file
    SFXZIPDecoder _decoder;             // gzip decoder
    SFXAnsiStringStreamReader  _reader; // input stream
    SFXAnsiString _unzipString;         // decompressed string
public:
    Void Start(Void);

    // callback function
    XALLBACK_DECLARE_SFXANSISTRINGSTREAMREADER(OnFetch)
};

Void MyClass::Start(Void)
{
    SFCError error; // error value

    // open the file in the read only mode
    if ((error = _file.OpenReadOnly(SFXPath("/testdata.tar.gz"))) == SFERR_NO_ERROR) {

        // set the file storage to the gzip decoder
        if ((error = _decoder.Open(_file)) == SFERR_NO_ERROR) {

            // get the input stream from the gzip decoder
            // * the stream buffer is variable since the size argument is not specified
            if ((error = _decoder.GetStreamReader(&_reader)) == SFERR_NO_ERROR) {

                // perform fetch: read the gzipped data from the gzip decoder into the stream buffer actually
                // *1. the fetch result will be notified to the OnFetch function
                // *2. the stream buffer will be expanded automatically depending on the size of data to be received
                if ((error = _reader.Fetch(XALLBACK_INTERNAL(OnFetch))) != SFERR_NO_ERROR) {

                    // if an error occurs
                    _reader.Release();
                }
            }
            if (error != SFERR_NO_ERROR) { 

                // if an error occurs
                _decoder.Close();
            }
        }
        if (error != SFERR_NO_ERROR) { 

            // if an error occurs
            _file.Close();
        }
    }
}

// callback function notified of the fetch result
XALLBACK_IMPLEMENT_SFXANSISTRINGSTREAMREADER(MyClass, OnFetch, error)
{
    if (error == SFERR_NO_ERROR) {  
        // if no error occurs in fetch

        // read data from the stream buffer into the _unzipString variable(at this time, data has already been decompressed)
        if ((error = _reader.ReadSFXAnsiString(&_unzipString)) == SFERR_NO_ERROR) {

            // display the _unzipString variable on BREW Output Window
            TRACE("%s", _unzipString.GetCString());

            _reader.Release();
        }
    }

    // termination
    _decoder.Close();
    _file.Close();
}

Reference

SFBAStream | SFBSource

Member

Description

This constructor does nothing.

Description

This destructor calls the SFXZIPDecoder::Close function.

	Note
	Registered callback functions will be canceled.

Reference

SFXZIPDecoder::Close

Return value

Description

This function converts the input stream used internally by this SFXZIPDecoder storage into the SFBAStream instance.

As a result, a pointer to the SFBAStream instance will be returned into the result argument.

	Note
	The contents of the SFXZIPDecoder storage can be handled as the SFBAStream instance.

Reference

SFXZIPDecoder::Open | SFBUnzipAStream | SFBAStream

Return value

Description

This function converts the input stream used internally by this SFXZIPDecoder storage into the SFBSource instance.

As a result, a pointer to the SFBSource instance will be returned into the result argument.

	Note
	This function internally calls the BREW API ISOURCEUTIL_SourceFromAStream function.

	Note
	The contents of the SFXZIPDecoder storage can be handled as the SFBSource instance.

Reference

SFXZIPDecoder::Open | SFBUnzipAStream | SFBSource | SFBSourceUtil | BREW API ISOURCEUTIL_SourceFromAStream

Description

This function cancels scheduling with the SFXZIPDecoder::ScheduleRead function.

The registered callback functions will be canceled.

	Note
	This function is called in the SFXZIPDecoder::Close function.

Reference

SFXZIPDecoder::ScheduleRead | SFXZIPDecoder::Close

Description

This function closes (or finishes) this ZIPDecoder storage.

Concretely, this function calls the SFXZIPDecoder::Cancel function and releases the SFBUnzipAStream instance that this ZIPDecoder storage internally manages.

	Note
	The registered callback functions will be canceled.

	Note
	This function is called in the SFXZIPDecoder::~SFXZIPDecoder destructor.

	Tip
	When suspending, resources should be released by calling this function.

Reference

SFXZIPDecoder::Cancel | SFXZIPDecoder::~SFXZIPDecoder | SFXZIPDecoder::Open | SFBUnzipAStream

Return value

SFBUnzipAStream instance managed internally by this SFXZIPDecoder storage.

Description

This function gets the SFBUnzipAStream instance managed internally by this SFXZIPDecoder storage.

Reference

SFBUnzipAStream | BREW API IUnzipAStream

Return value

Description

This function gets the input stream for reading data from this SFXZIPDecoder storage.

If the size argument is specified, the buffer size of the input stream will be fixed with the specified value. Otherwise, the buffer size will be variable and the SFXElasticStreamReader class will be used internally.

	Tip
	You have to use the SFXBinaryStreamReader, SFXAnsiStringStreamReader, or SFXWideStringStreamReader class for the input stream properly depending on the type of data to be read.

	Caution
	Before calling this function, you have to register the source into this SFXZIPDecoder storage with the SFXZIPDecoder::Open function.

Reference

SFXZIPDecoder::Open | SFXBinaryStreamReader | SFXAnsiStringStreamReader | SFXWideStringStreamReader | Stream Buffer

Return value

SFERR_UNSUPPORTED

Description

[This function cannot be used now.]

Reference

SFXZIPDecoder::GetStreamReader

Return value

Description

This function sets the specified compressed stream, storage or source as the source for the SFBUnzipAStream instance that this SFXZIPDecoder storage manages internally.

The SFXStorage, SFBAStream or SFBSource instance can be specified in the argument.

After this function is executed, the gzipped data will be read and decoded at the same time by using the input stream obtained with the SFXZIPDecoder::GetStreamReader function or by calling the SFXZIPDecoder::Read function.

Note

This function internally calls the SFBUnzipAStream::SetStream function to set the specified compressed stream, storage or source as the source for the SFBUnzipAStream instance that this SFXZIPDecoder storage manages internally. At this time, the storage and the source internally will be converted into the stream with the AsSFBAStream function and the SFBSourceUtil::AStreamFromSource function respectively.

Reference

SFBUnzipAStream::SetStream | SFXZIPDecoder::Close | SFXZIPDecoder::GetStreamReader | SFXZIPDecoder::Read | SFXStorage | SFBAStream | SFBSource | SFBUnzipAStream | BREW API IUNZIPASTREAM_SetStream

Argument

Return value

Description

This function reads data from this ZIPDecoder without input stream.

When all data has been read from this ZIPDecoder, this function will return SFERR_NO_ERROR and 0 will be returned into the area that the size argument points to.

* If this function returns AEE_STREAM_WOULDBLOCK, it will be necessary to register a callback function with the SFXZIPDecoder::ScheduleRead function where data will be read with this function.

	Note
	This function internally calls the SFBAStream::Read function.

	Prerequisite
	This ZIPDecoder needs to be opened (or set) with the SFXZIPDecoder::Open function before this function is called.

Reference

SFXZIPDecoder::Open | SFXZIPDecoder::ScheduleRead | SFBAStream::Read | BREW API IUNZIPASTREAM_Read

Return value

Description

This function schedules to read data from this ZIPDecoder without input stream.

Concretely, this function registers the callback function that will read data with the SFXZIPDecoder::Read function. The registered callback function will be called by BREW AEE when it is possible to read data.

The status of this ZIPDecoder is "under scheduling to read data" until the callback function is called. And after the callback function is called, it will become the status before calling this function, i.e., "this ZIPDecoder is opened".

If you call the SFXZIPDecoder::Cancel function before the callback function is called, reading data will be canceled and the status will be returned to the status before calling this function, i.e., "this ZIPDecoder is opened".

*1. If the SFXZIPDecoder::Read function returns AEE_STREAM_WOULDBLOCK, it will be necessary to register a callback function with this function where data will be read with the SFXZIPDecoder::Read function.

*2. If this function returns the value other than SFERR_NO_ERROR, the specified callback function will not be called.

	Note
	This function internally calls the SFBAStream::Readable function.

	Prerequisite
	This ZIPDecoder needs to be opened (or set) with the SFXZIPDecoder::Open function before this function is called. And if this ZIPDecoder has been already scheduled to read data, the SFERR_INVALID_STATE error will be returned.

Reference

SFXZIPDecoder::Read | SFXZIPDecoder::Open | SFXZIPDecoder::Cancel | SFBAStream::Readable | SFXStorage::CallbackSPP | BREW API IUNZIPASTREAM_Readable

Return value

SFERR_UNSUPPORTED

Description

[This function cannot be used now.]

Reference

SFXStorage::CallbackSPP

Return value

SFERR_UNSUPPORTED

Description

[This function cannot be used now.]