RC PF_FileHandle::GetNextPage (PageNum current, PF_PageHandle &pageHandle) const {
/* Search for the next allocated page on disk */
for (PageNum i = current+1; i <= pageCount; i++) {
if (GetPageType(i) == ALLOCATED_PAGE) {
return GetThisPage(i, pageHandle);
}
}
/* If search failed return EOF */
return PF_EOF;
}
const RC AllocatePage(PF_FileHandle *fileHandle,PF_PageHandle *pageHandle)
{
PF_PageHandle *pPageHandle=pageHandle;
RC tmp;
int i,byte,bit;
fileHandle->pHdrFrame->bDirty=true;
if((fileHandle->pFileSubHeader->nAllocatedPages)<=(fileHandle->pFileSubHeader->pageCount)){
for(i=0;i<=fileHandle->pFileSubHeader->pageCount;i++){
byte=i/8;
bit=i%8;
if(((fileHandle->pBitmap[byte])&(1<<bit))==0){
(fileHandle->pFileSubHeader->nAllocatedPages)++;
fileHandle->pBitmap[byte]|=(1<<bit);
break;
}
}
if(i<=fileHandle->pFileSubHeader->pageCount)
return GetThisPage(fileHandle,i,pageHandle);
}
fileHandle->pFileSubHeader->nAllocatedPages++;
fileHandle->pFileSubHeader->pageCount++;
byte=fileHandle->pFileSubHeader->pageCount/8;
bit=fileHandle->pFileSubHeader->pageCount%8;
fileHandle->pBitmap[byte]|=(1<<bit);
if((tmp=AllocateBlock(&(pPageHandle->pFrame)))!=SUCCESS){
return tmp;
}
pPageHandle->pFrame->bDirty=false;
pPageHandle->pFrame->fileDesc=fileHandle->fileDesc;
pPageHandle->pFrame->fileName=fileHandle->fileName;
pPageHandle->pFrame->pinCount=1;
pPageHandle->pFrame->accTime=clock();
memset(&(pPageHandle->pFrame->page),0,sizeof(Page));
pPageHandle->pFrame->page.pageNum=fileHandle->pFileSubHeader->pageCount;
if(_lseek(fileHandle->fileDesc,0,SEEK_END)==-1){
bf_manager.allocated[pPageHandle->pFrame-bf_manager.frame]=false;
return PF_FILEERR;
}
if(_write(fileHandle->fileDesc,&(pPageHandle->pFrame->page),sizeof(Page))!=sizeof(Page)){
bf_manager.allocated[pPageHandle->pFrame-bf_manager.frame]=false;
return PF_FILEERR;
}
return SUCCESS;
}
