private FileHeader m_fileHeader; //the only file header in the two files, it is located at page 0.
public memSegmentManager(DiskFile file)
{
m_cache = new CacheHashtable(m_cacheSize);
m_pageSize = 1 << m_pageBits;
m_diskFile = file;
m_bitmap = new PageBitmap();
m_fileHeader = new FileHeader();
if (file.Length < m_bitmap.Data.Length + m_pageSize * 2) //page 0 for fileheader, page 33 for segTree, page 44 for spacetree
{
//this helper file is a new one
for (int i = 0; i < (m_bitmap.Data.Length >> (m_pageBits + 3)); i++)
{
m_bitmap.Data[i] = 0xFF;
}
m_bitmap.SetPageTaken(m_bitmap.GetFirstFreePageID()); //one more page taken because of the fileheader
m_bitmap.Dirty = true;
m_fileHeader.SetInitializeNeeded();
}
else
{
byte[] header = file.SynRead(0, m_pageSize);
m_fileHeader.Deserialize(header);
file.SynRead(m_bitmap.Data, 0, m_pageSize, m_bitmap.Data.Length);
}
m_LRU = new BNode();
}
private FileHeader m_fileHeader; //the only file header in the two files, it is located at page 0.
public memSegmentManager(DiskFile file)
{
m_cache = new CacheHashtable(m_cacheSize);
m_pageSize = 1 << m_pageBits;
m_diskFile = file;
m_bitmap = new PageBitmap();
m_fileHeader = new FileHeader();
if (file.Length < m_bitmap.Data.Length + m_pageSize*2) //page 0 for fileheader, page 33 for segTree, page 44 for spacetree
{
//this helper file is a new one
for (int i=0; i<(m_bitmap.Data.Length >> (m_pageBits + 3)); i++)
m_bitmap.Data[i] = 0xFF;
m_bitmap.SetPageTaken(m_bitmap.GetFirstFreePageID()); //one more page taken because of the fileheader
m_bitmap.Dirty = true;
m_fileHeader.SetInitializeNeeded();
}
else
{
byte[] header = file.SynRead(0, m_pageSize);
m_fileHeader.Deserialize(header);
file.SynRead(m_bitmap.Data, 0, m_pageSize, m_bitmap.Data.Length);
}
m_LRU = new BNode();
}
public override void GetNewSegment(Segment seg)
{
uint segId = m_bitmap.GetFirstFreePageID();
seg.Initialize(segId);
m_bitmap.SetPageTaken(segId);
//put the new node into cache
//kick out one if needed
_put_in_cache(seg);
}
