private void LruInsert(HeadT h)
{
// insert to last position
h.next = lruHead;
h.prev = lruHead.prev;
h.prev.next = h;
h.next.prev = h;
}
public void SwapIndex(int i, int j)
{
if (i == j)
{
return;
}
if (head[i].len > 0)
{
LruDelete(head[i]);
}
if (head[j].len > 0)
{
LruDelete(head[j]);
}
Swap(ref head[i].data, ref head[j].data);
Swap(ref head[i].len, ref head[j].len);
if (head[i].len > 0)
{
LruInsert(head[i]);
}
if (head[j].len > 0)
{
LruInsert(head[j]);
}
if (i > j)
{
Swap(ref i, ref j);
}
for (HeadT h = lruHead.next; h != lruHead; h = h.next)
{
if (h.len > i)
{
if (h.len > j)
{
Swap(ref h.data[i], ref h.data[j]);
}
else
{
// give up
LruDelete(h);
size += h.len;
h.data = null;
h.len = 0;
}
}
}
}
public Cache(int count, long size)
{
this.count = count;
this.size = size;
head = new HeadT[this.count];
for (int i = 0; i < this.count; i++)
{
head[i] = new HeadT(this);
}
this.size /= 4;
this.size -= this.count * (16 / 4); // sizeof(head_t) == 16
lruHead = new HeadT(this);
lruHead.next = lruHead.prev = lruHead;
}
// request data [0,len)
// return some position p where [p,len) need to be filled
// (p >= len if nothing needs to be filled)
// java: simulate pointer using single-element array
public int GetData(int index, ref float[] data, int len)
{
HeadT h = head[index];
if (h.len > 0)
{
LruDelete(h);
}
int more = len - h.len;
if (more > 0)
{
// free old space
while (size < more)
{
HeadT old = lruHead.next;
LruDelete(old);
size += old.len;
old.data = null;
old.len = 0;
}
// allocate new space
float[] newData = new float[len];
if (h.data != null)
{
Array.Copy(h.data, 0, newData, 0, h.len);
}
h.data = newData;
size -= more;
Swap(ref h.len, ref len);
}
LruInsert(h);
data = h.data;
return(len);
}
private static void LruDelete(HeadT h)
{
// delete from current location
h.prev.next = h.next;
h.next.prev = h.prev;
}