hxbufdataf.cpp

linux下的一款播放器

//      written are return.  If errors occur, -1 is returned.  The
//      LastError() member function returns the value of errno from
//      the last system request.
//
STDMETHODIMP_(ULONG32)
HXBufferedDataFile::Write(REF(IHXBuffer *) pBuf)
{
    if (m_Fd >= 0)
    {
	pBuf->AddRef();

	ULONG32 count = pBuf->GetSize();
	ULONG32 nleft = count;
	INT32 rval = 0;
	const unsigned char* buf = pBuf->GetBuffer();
	while (nleft > 0)
	{
				// If we enter this block, m_Offset
				// lies within the current buffer.
	    if (m_Begin <= m_Offset && m_Offset < m_Begin + m_BufSize ||
		(rval = NewBuf()) >= 0)
	    {
		UINT32 off = m_Offset - m_Begin;  // offset within buffer
						  // and how much to copy
		UINT32 ncopy = m_Begin + m_BufSize - m_Offset;
		if (nleft < ncopy)
		    ncopy = nleft;
		::memcpy((void*) (m_pBuf+off), (const void*) buf, ncopy); /* Flawfinder: ignore */
		m_Dirty = 1;
		nleft -= ncopy;
		m_Offset += ncopy;
		buf += ncopy;
				// data extend beyond what was read in
		if (m_Offset-m_Begin > m_BufFill)
		    m_BufFill = m_Offset-m_Begin;
	    }
				// NewBuf() could not make the above
				// assertion, true because an error occured.
	    else
		break;
	}
	pBuf->Release();
	return rval >= 0 ? count - nleft : HXR_FAIL;
    }
    return HXR_FAIL;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::Flush()
// Purpose:
//     Flush out the data in case of buffered I/O
//  
STDMETHODIMP
HXBufferedDataFile::Flush()
{
    if (m_Flags & HX_FILEFLAG_WRITE)
	return FlushBuf() > 0 ? HXR_OK : HXR_FAIL;

    return HXR_OK;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::Stat
// Purpose:
//     Return info about the data file such as permissions, time of
//     creation size in bytes, etc.  Note that if this method is
//     called with unflushed extensions to the file, the st_size field
//     will not be correct.  We could Flush before filling in the stat
//     data, but this is a const function.  The other alternative is
//     to set the st.st_size field to the value returned by
//     LogicalSize() (which includes unflushed extensions to the
//     file).
//
STDMETHODIMP
HXBufferedDataFile::Stat(struct stat* buf)
{
    return GetFileStat(buf);
}

STDMETHODIMP_(INT16)
HXBufferedDataFile::GetFd()
{   
    return m_Fd;
}
	
/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::GetLastError:
// Purpose:
//     Returns the value of errno from the last system request.
//
STDMETHODIMP
HXBufferedDataFile::GetLastError()
{
    return m_LastError;
}

STDMETHODIMP_(void) 
HXBufferedDataFile::GetLastError(REF(IHXBuffer*) err)
{
    char* str = ::strerror(m_LastError);
    err = new CHXBuffer;
    err->Set((BYTE*) str, ::strlen(str)+1);
    err->AddRef();
}

/////////////////////////////////////////////////////////////////////////
//
//  Method:
//      HXBufferedDataFile::FlushSize():
//  Purpose:
//       Return flushed file size.  We assume that only this object
//       has changed the size of the file.  The size returned does NOT
//       include bytes in the buffer not yet flushed to the file.
//
ULONG32
HXBufferedDataFile::FlushSize()
{
    if (m_FlushSize == 0)
    {
	struct stat st;
	if (GetFileStat(&st) == HXR_OK)
	    m_FlushSize = st.st_size;
    }
    return m_FlushSize;
}

/////////////////////////////////////////////////////////////////////////
//
//  Method:
//      HXBufferedDataFile::LogicalSize():
//  Purpose:
//       Return logical file size.  We assume that only this object
//       has changed the size of the file.  The size returned includes
//       bytes in the buffer not yet flushed to the file.
//
ULONG32
HXBufferedDataFile::LogicalSize()
{
				// If the flushed size is <= the
				// beginning of the current buffer,
				// we have extended the file, but
				// have not flushed it.
    ULONG32 size = FlushSize();
    if (size <= m_Begin)
    {
	size = m_Begin + m_BufFill;
    }
    return size;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::NewBuf:
//  Purpose:
//      Utility method.
//      Request an new i/o buffer.  If the file is open for writing,
//      the buffer is flushed if marked dirty.  If the file is open
//      for reading a new buffer containing the current seek offset is
//      read in from the file.  Note for files open for writing, the
//      current buffer is flushed, before the new buffer is read in.
//      Returns vales:
//
//         1       Buffer was successfully refreshed.
//         0       If file is open for reading, cureent seek offset
//                 is at or beyond EOF.
//        -1       Error occured during flushing or filling.
//
INT32 HXBufferedDataFile::NewBuf()
{
    int status = 1;
				// if writing flush the current buffer 
    if (m_Flags & HX_FILEFLAG_WRITE)
    {
	status = FlushBuf();
    }
				// fill buffer from file
    if (status > 0)
    {
	status = FillBuf();
    }
    return status;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::FillBuf:
//
// Purpose   
//      Utility method:
//      Fill buffer with file contents at current offset.
//      Returns:
//         1   Buffer filled.  If End of Buffer is beyond EOF,
//             buffer is partially filled.  m_BufFill is set
//             to how much of buffer is filled.
//         0   End of File
//        -1   Read or seek error, or file not open
//
INT32
HXBufferedDataFile::FillBuf()
{
    int status = -1;
    m_LastError = 0;
    if (m_Fd >= 0)
    {
				// Get beginning of buffer on a
				// m_BufSize boundry.  If the beginning
				// of the buffer is less then the current
				// flushed file size, seek and read it in.
	m_Begin = (m_Offset/m_BufSize)*m_BufSize;
	m_BufFill = 0;
	if (m_Begin < FlushSize())
	{
	    INT32 rval = -1;
	    m_BufFill = 0;
	    if ((rval = Pread((void*) m_pBuf, m_BufSize, m_Begin)) > 0)
	    {
		m_BufFill = rval;
		status = 1;
	    }
	    else if (rval < 0)	// lseek or read error
	    {
		m_LastError = errno;
		status = -1;
	    }
	    else		// EOF: zero buffer
	    {
		::memset((void*) m_pBuf, 0, m_BufSize);
		status = 0;
	    }
	}
	else			// m_Begin is beyond EOF: zero buffer
	{
	    ::memset((void*) m_pBuf, 0, m_BufSize);
	    status = 0;
	}
    }
    return status;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::FlushBuf:
// Purpose:
//    Utility method:
//    If file is open for writing and the current i/o buffer is dirty,
//    write the contents to the file.
//    Returns:
//         1   Buffer Flushed.
//        -1   Read or seek error, or file not open or read only.
//
INT32
HXBufferedDataFile::FlushBuf()
{
    int status = -1;
    m_LastError = 0;
    if (m_Fd >= 0 && (m_Flags & HX_FILEFLAG_WRITE))
    {
				// buffer has been scribbled on.
	if (m_Dirty && m_BufFill > 0)
	{
	    int rval = -1;
	    if ((rval = Pwrite((const void*) m_pBuf, m_BufFill, m_Begin)) > 0)
	    {
		status = 1;
		m_Dirty = 0;
	    }
	    else
	    {
		status = -1;
		m_LastError = errno;
	    }
	}
	else			// already flushed.
	    status = 1;
    }
    return status;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::AllocBuf:
// Purpose:
//     Allocate  the i/o buffer off of heap.
//
void
HXBufferedDataFile::AllocBuf()
{
    if (m_pBuf == 0)
    {
	m_pBuf = new char[m_BufSize];
    }
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::FreeBuf:
//  Purpose:
//     Free the i/o buffer.
//
void
HXBufferedDataFile::FreeBuf()
{
    delete [] m_pBuf;
    m_pBuf = 0;
    m_BufFill = 0;
    m_Begin = 0;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::Pread:
// Purpose:
//     Read data at requrested position.
//     Number of bytes read is returned 0 if at EOF, or -1 on error
//
INT32
HXBufferedDataFile::Pread(void* buf, INT32 nbytes, ULONG32 offset)
{
    //INT32 nread = -1;
	OpFsSize nread = kOpFsErrAny;
    m_LastError = 0;
    if (m_Fd >= 0)
    {
	if (m_FileOffset == offset ||
	   // ::lseek(m_Fd, offset, SEEK_SET) != -1)
	   OpFsSeek( m_Fd, (OpFsSize)offset, SEEK_SET) != kOpFsErrAny)
	{
	    m_FileOffset = offset;
	    //if ((nread = ::read(m_Fd, buf, nbytes)) > 0)
		if ((nread = OpFsRead( m_Fd, buf, nbytes)) != kOpFsErrAny)
			m_FileOffset += nread;
	    else if (nread < 0)
			m_LastError = errno;
	}
    }
    return nread;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::Pwrite:
// Purpose:
//     Write data at requrested position.
//     Number of bytes read is returned, or -1 on error
//
INT32
HXBufferedDataFile::Pwrite(const void* buf, INT32 nbytes, ULONG32 offset)
{
    //INT32 nwrite = -1;
	OpFsSize nwrite = kOpFsErrAny;
    m_LastError = 0;
    if (m_Fd >= 0)
    {
	if (m_FileOffset == offset ||
	    //::lseek(m_Fd, offset, SEEK_SET) != -1)
		OpFsSeek( m_Fd, (OpFsSize)offset, SEEK_SET) != kOpFsErrAny)
	{
	    m_FileOffset = offset;
	    //if ((nwrite = ::write(m_Fd, buf, nbytes)) > 0)
		if (( nwrite = OpFsWrite( m_Fd, buf, nbytes)) != kOpFsErrAny)
	    {
			m_FileOffset += nwrite;
			if (m_FileOffset > m_FlushSize)
				m_FlushSize = m_FileOffset;
	    }
	    else
			m_LastError = errno;
	}
    }
    return nwrite;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::GetFileStat
//  Purpose
//   Get file stat. If all is of HXR_OK is returned otherwise HXR_FAIL
//
INT32
HXBufferedDataFile::GetFileStat(struct stat* st) const
{
    INT32 status = HXR_FAIL;
    if ((m_Fd >= 0 && ::fstat(m_Fd, st) == 0) ||
	(m_pFileName->GetSize() &&
	 ::stat((const char*) m_pFileName->GetBuffer(), st) == 0))
    {
	status = HXR_OK;
    }
				// cast to get around const
    ((HXBufferedDataFile*) this)->m_LastError = status == HXR_OK ? 0 : errno;
    return status;
}

/////////////////////////////////////////////////////////////////////////
//
// Method:
//     HXBufferedDataFile::GetPageSize:
// Purpose:
//    Get the system page size.

INT32
HXBufferedDataFile::GetPageSize() const
{
#if defined(_FREEBSD)
    return getpagesize();
#else
    //return ::sysconf(_SC_PAGE_SIZE);
	return 0;  // On Openwave platform, pages service not available
#endif
}