public LRUHashEntry()
{
m_key = null;
m_data = null;
m_next = null;
m_LRU_prev = m_LRU_next = this;
}
public void BreakLinks()
{
m_LRU_prev.m_LRU_next = m_LRU_next;
m_LRU_next.m_LRU_prev = m_LRU_prev;
m_LRU_prev = m_LRU_next = this;
}
public LRUHashEntry(object key, object data)
{
m_key = key;
m_data = data;
m_next = null;
m_LRU_prev = m_LRU_next = this;
}
public void BreakLinks()
{
m_LRU_prev.m_LRU_next = m_LRU_next;
m_LRU_next.m_LRU_prev = m_LRU_prev;
m_LRU_prev = m_LRU_next = this;
}
public LRUHashEntry()
{
m_key = null;
m_data = null;
m_next = null;
m_LRU_prev = m_LRU_next = this;
}
public LRUHashEntry(object key, object data)
{
m_key = key;
m_data = data;
m_next = null;
m_LRU_prev = m_LRU_next = this;
}
public LRUHashtable(int size, int limit)
{
m_size = size;
m_items = new LRUHashEntry[size];
m_count = 0;
m_cache_limit = limit;
m_LRU = new LRUHashEntry();
}
public void BuildLinks(LRUHashEntry LRU_prev, LRUHashEntry LRU_next)
{
LRU_prev.m_LRU_next = this;
LRU_next.m_LRU_prev = this;
m_LRU_prev = LRU_prev;
m_LRU_next = LRU_next;
}
public void BuildLinks(LRUHashEntry LRU_prev, LRUHashEntry LRU_next)
{
LRU_prev.m_LRU_next = this;
LRU_next.m_LRU_prev = this;
m_LRU_prev = LRU_prev;
m_LRU_next = LRU_next;
}
public bool Insert(object key, object data)
{
if (m_count >= m_cache_limit)
{
//kick one out
LRUHashEntry victim = m_LRU.LRU_Prev;
bool t = Delete(victim.Key);
Debug.Assert(t);
}
int pos = (int)(Math.Abs(key.GetHashCode()) % m_size);
LRUHashEntry head = m_items[pos];
if (head == null)
{
LRUHashEntry ent = new LRUHashEntry(key, data);
m_items[pos] = ent;
//put his into the front of the LRU list
ent.BuildLinks(m_LRU, m_LRU.LRU_Next);
}
else
{
while (head.Next != null &&head.Key != key)
{
head = head.Next;
}
if (head.Key.Equals(key))
throw new OOD.Exception.ProgramLogicError(this, "Insert an existing key into the hashtable");
else
{
LRUHashEntry e = new LRUHashEntry(key, data);
head.Next = e;
e.BuildLinks(m_LRU, m_LRU.LRU_Next);
}
}
m_count ++;
return true;
}
public bool MoveNext()
{
if (m_current == null)
{
while (m_row < m_table.m_size && m_table.m_items[m_row] == null)
{
m_row ++;
}
if (m_row < m_table.m_size)
m_current = m_table.m_items[m_row];
else
m_current = null;
m_row ++;
}
else
{
if (m_current.Next != null)
m_current = m_current.Next;
else
{
while (m_row < m_table.m_size && m_table.m_items[m_row] == null)
{
m_row ++;
}
if (m_row < m_table.m_size)
m_current = m_table.m_items[m_row];
else
m_current = null;
m_row ++;
}
}
return m_current != null;
}