compress.hpp

ncbi源码

    virtual bool Close(void) = 0;

protected:
    TFile  m_File;   // File handler
    EMode  m_Mode;   // File open mode
};



//////////////////////////////////////////////////////////////////////////////
//
// CCompressionProcessor -- abstract base class
//
// Contains a functions for service a compression/decompression session.
//

class NCBI_XUTIL_EXPORT CCompressionProcessor
{
public:
    // Type of the result of all basic functions
    enum EStatus {
        // Everything is fine, no errors occurred
        eStatus_Success,
        // Special case of eStatus_Success.
        // Logical end of (compressed) stream is detected, no errors occurred.
        // All subsequent inquiries about data processing should be ignored.
        eStatus_EndOfData,
        // Error has occurred. The error code can be acquired by GetLastError.
        eStatus_Error,
        // Output buffer overflow - not enough output space.
        // Buffer must be emptied and the last action repeated.
        eStatus_Overflow
    };

    // 'ctors
    CCompressionProcessor(void);
    virtual ~CCompressionProcessor(void);

    // Return compressor's busy flag. If returns value is true that
    // the current compression object already have being use in other
    // compression session.
    bool IsBusy(void) const;

    // Return number of processed/output bytes.
    unsigned long GetProcessedSize(void);
    unsigned long GetOutputSize(void);

protected:
    // Initialize the internal stream state for compression/decompression.
    // It does not perform any compression, this will be done by Process().
    virtual EStatus Init(void) = 0;

    // Compress/decompress as much data as possible, and stops when the input
    // buffer becomes empty or the output buffer becomes full. It may
    // introduce some output latency (reading input without producing any
    // output).
    virtual EStatus Process
    (const char*    in_buf,      // [in]  input buffer 
     unsigned long  in_len,      // [in]  input data length
     char*          out_buf,     // [in]  output buffer
     unsigned long  out_size,    // [in]  output buffer size
     unsigned long* in_avail,    // [out] count unproc.bytes in input buffer
     unsigned long* out_avail    // [out] count bytes putted into out buffer
     ) = 0;

    // Flush compressed/decompressed data from the output buffer. 
    // Flushing may degrade compression for some compression algorithms
    // and so it should be used only when necessary.
    virtual EStatus Flush
    (char*          out_buf,     // [in]  output buffer
     unsigned long  out_size,    // [in]  output buffer size
     unsigned long* out_avail    // [out] count bytes putted into out buffer
     ) = 0;

    // Finish the compression/decompression process.
    // Process pending input, flush pending output.
    // This function slightly like to Flush(), but it must be called only
    // at the end of compression process before End().
    virtual EStatus Finish
    (char*          out_buf,     // [in]  output buffer
     unsigned long  out_size,    // [in]  output buffer size
     unsigned long* out_avail    // [out] count bytes putted into out buffer
     ) = 0;

    // Free all dynamically allocated data structures.
    // This function discards any unprocessed input and does not flush
    // any pending output.
    virtual EStatus End(void) = 0;

protected:
    // Reset internal state
    void Reset(void);

    // Set/unset compressor busy flag
    void SetBusy(bool busy = true);

    // Increase number of processed/output bytes.
    void IncreaseProcessedSize(unsigned long n_bytes);
    void IncreaseOutputSize(unsigned long n_bytes);

private:
    unsigned long m_ProcessedSize; //< The number of processed bytes
    unsigned long m_OutputSize;    //< The number of output bytes
    bool          m_Busy;          //< Is true if compressor is ready to begin
                                   //< next session
    // Friend classes
    friend class CCompressionStream;
    friend class CCompressionStreambuf;
};



/* @} */


//
// Inline functions
//

inline
void CCompression::SetLevel(ELevel level)
{
    m_Level = level;
}

inline
int CCompression::GetErrorCode(void) const
{
    return m_ErrorCode;
}

inline
string CCompression::GetErrorDescription(void) const
{
    return m_ErrorMsg;
}

inline
void CCompression::SetError(int errcode, const char* description)
{
    m_ErrorCode = errcode;
    m_ErrorMsg  = description ? description : kEmptyStr;
}

inline
CCompression::TFlags CCompression::GetFlags(void) const
{
    return m_Flags;
}

inline
void CCompression::SetFlags(TFlags flags)
{
    m_Flags = flags;
}

inline
void CCompressionProcessor::Reset(void)
{
    m_ProcessedSize  = 0;
    m_OutputSize     = 0;
    m_Busy           = false;
}

inline
bool CCompressionProcessor::IsBusy(void) const
{
    return m_Busy;
}

inline
void CCompressionProcessor::SetBusy(bool busy)
{
    if ( busy  &&  m_Busy ) {
        NCBI_THROW(CCompressionException, eCompression,
                   "CCompression::SetBusy(): The compressor is busy now");
    }
    m_Busy = busy;
}

inline
void CCompressionProcessor::IncreaseProcessedSize(unsigned long n_bytes)
{
    if (n_bytes > 0) {
        m_ProcessedSize += n_bytes;
    }
}

inline
void CCompressionProcessor::IncreaseOutputSize(unsigned long n_bytes)
{
    if (n_bytes > 0) {
        m_OutputSize += n_bytes;
    }
}

inline
unsigned long CCompressionProcessor::GetProcessedSize(void)
{
    return m_ProcessedSize;
}

inline
unsigned long CCompressionProcessor::GetOutputSize(void)
{
    return m_OutputSize;
}


END_NCBI_SCOPE


/*
 * ===========================================================================
 * $Log: compress.hpp,v $
 * Revision 1000.2  2004/06/01 19:39:20  gouriano
 * PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.8
 *
 * Revision 1.8  2004/05/10 11:56:24  ivanov
 * Added gzip file format support
 *
 * Revision 1.7  2004/04/01 14:14:02  lavr
 * Spell "occurred", "occurrence", and "occurring"
 *
 * Revision 1.6  2003/07/15 15:50:00  ivanov
 * Improved error diagnostics. Renamed GetLastError() -> GetErrorCode().
 * Added GetErrorDescription(). Added second parameter for SetError().
 * Added new status value - eStatus_EndOfData.
 *
 * Revision 1.5  2003/07/10 16:19:25  ivanov
 * Added kCompressionDefaultBufSize definition from stream.hpp.
 * Added auxiliary file compression/decompression functions.
 *
 * Revision 1.4  2003/06/03 20:09:54  ivanov
 * The Compression API redesign. Added some new classes, rewritten old.
 *
 * Revision 1.3  2003/04/11 19:57:25  ivanov
 * Move streambuf.hpp from 'include/...' to 'src/...'
 *
 * Revision 1.2  2003/04/08 20:48:51  ivanov
 * Added class-key declaration for friend classes in the CCompression
 *
 * Revision 1.1  2003/04/07 20:42:11  ivanov
 * Initial revision
 *
 * ===========================================================================
 */

#endif  /* UTIL_COMPRESS__COMPRESS__HPP */