//-----------------------------------------------------------------------------------------------
// GetPage
//
// Updates the page handle with the page with the given pageID
//-----------------------------------------------------------------------------------------------
t_rc STORM_FileHandle::GetPage(int pageID, STORM_PageHandle &pageHandle)
{
STORM_Frame *pFrame;
t_rc rc;
if (!m_isOpened)
return (STORM_FILENOTOPENED);
// Check if page is not valid.
if (pageID < 1)
return (STORM_INVALIDPAGE);
if (pageID > m_fileSubHeader.numAllocatedPages)
return (STORM_INVALIDPAGE);
if (!IsPageReserved(pageID))
return (STORM_INVALIDPAGE);
rc = m_pBfrMgr->NeedPage(m_fileID, pageID, &pFrame);
if (rc != OK) return (rc);
rc = pageHandle.Open(pFrame);
m_filePos = pageID;
return (rc);
}
//-----------------------------------------------------------------------------------------------
// ReservePage
//
// Reserves a new page for the file.
//-----------------------------------------------------------------------------------------------
t_rc STORM_FileHandle::ReservePage(STORM_PageHandle &pageHandle)
{
if (!m_isOpened)
return (STORM_FILENOTOPENED);
t_rc rc;
int newPageID = INVALID_PAGEID;
for (int pageCounter=1; pageCounter<=MAX_PAGES_PER_FILE; pageCounter++)
{
if (!IsPageReserved(pageCounter))
{
newPageID = pageCounter;
break;
}
}
STORM_Frame *pFrame;
if (newPageID == INVALID_PAGEID) // all pages are reserved
{
if (m_fileSubHeader.numAllocatedPages == MAX_PAGES_PER_FILE)
return STORM_FILELIMITREACHED;
// Reserve frame in buffer.
rc = m_pBfrMgr->ReserveFrame(m_fileID, newPageID, &pFrame);
if (rc != OK) return (rc);
m_fileSubHeader.numAllocatedPages++;
m_fileSubHeader.numReservedPages++;
UpdateHeaderFrame();
rc = m_pBfrMgr->WritePage(pFrame);
if (rc != OK) return (rc);
}
else // a free page has been found
{
// Reserve frame in buffer.
rc = m_pBfrMgr->ReserveFrame(m_fileID, newPageID, &pFrame);
if (rc != OK) return (rc);
m_fileSubHeader.numReservedPages++;
UpdateHeaderFrame();
if (newPageID > m_fileSubHeader.numAllocatedPages)
{
rc = m_pBfrMgr->WritePage(pFrame);
if (rc != OK) return (rc);
m_fileSubHeader.numAllocatedPages++;
UpdateHeaderFrame();
}
}
SetPageReservationFlag(newPageID, true); // page is reserved now
rc = pageHandle.Open(pFrame);
if (rc != OK) return (rc);
return (OK);
}