void swap_index(int i, int j)
{
if(i==j) return;
if(head[i].len > 0) lru_delete(head[i]);
if(head[j].len > 0) lru_delete(head[j]);
do {float[] _=head[i].data; head[i].data=head[j].data; head[j].data=_;} while(false);
do {int _=head[i].len; head[i].len=head[j].len; head[j].len=_;} while(false);
if(head[i].len > 0) lru_insert(head[i]);
if(head[j].len > 0) lru_insert(head[j]);
if(i>j) do {int _=i; i=j; j=_;} while(false);
for(head_t h = lru_head.next; h!=lru_head; h=h.next)
{
if(h.len > i)
{
if(h.len > j)
do {float _=h.data[i]; h.data[i]=h.data[j]; h.data[j]=_;} while(false);
else
{
// give up
lru_delete(h);
size += h.len;
h.data = null;
h.len = 0;
}
}
}
}
private void lru_insert(head_t h)
{
// insert to last position
h.next = lru_head;
h.prev = lru_head.prev;
h.prev.next = h;
h.next.prev = h;
}
Cache(int l_, int size_)
{
l = l_;
size = size_;
head = new head_t[l];
for(int i=0;i<l;i++) head[i] = new head_t();
size /= 4;
size -= l * (16/4); // sizeof(head_t) == 16
lru_head = new head_t();
lru_head.next = lru_head.prev = lru_head;
}
// 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
int get_data(int index, float[][] data, int len)
{
head_t h = head[index];
if(h.len > 0) lru_delete(h);
int more = len - h.len;
if(more > 0)
{
// free old space
while(size < more)
{
head_t old = lru_head.next;
lru_delete(old);
size += old.len;
old.data = null;
old.len = 0;
}
// allocate new space
float[] new_data = new float[len];
if(h.data != null) System.arraycopy(h.data,0,new_data,0,h.len);
h.data = new_data;
size -= more;
do {int _=h.len; h.len=len; len=_;} while(false);
}
lru_insert(h);
data[0] = h.data;
return len;
}