mirror of
https://github.com/ltcptgeneral/cs239-caching.git
synced 2025-04-06 22:27:22 +00:00
116 lines
3.5 KiB
Python
116 lines
3.5 KiB
Python
from .cache import Cache
|
|
|
|
class Node:
|
|
def __init__(self, key, value):
|
|
self.key = key
|
|
self.value = value
|
|
self.visited = False
|
|
self.next = None
|
|
self.prev = None
|
|
|
|
class SieveCache(Cache):
|
|
def __init__(self, limit: int):
|
|
super().__init__(limit)
|
|
self.limit = limit # Fix: Store limit properly
|
|
self.cache = {} # Hash map for O(1) access
|
|
self.head = None
|
|
self.tail = None
|
|
self.hand = None
|
|
|
|
def print_cache_state(self):
|
|
print("Current cache state:")
|
|
node = self.head
|
|
if not node:
|
|
print("Cache is empty.")
|
|
return
|
|
for _ in range(len(self.cache)):
|
|
print(f"Key: {node.key}, Value: {node.value}, Visited: {node.visited}")
|
|
node = node.next
|
|
if node == self.head:
|
|
break
|
|
|
|
def get(self, key: str) -> str:
|
|
if key in self.cache:
|
|
node = self.cache[key]
|
|
node.visited = True
|
|
#self.print_cache_state()
|
|
return node.value
|
|
self.print_cache_state()
|
|
return None
|
|
|
|
def put(self, key: str, val: str) -> bool:
|
|
if key in self.cache:
|
|
node = self.cache[key]
|
|
node.value = val
|
|
node.visited = True
|
|
#self.print_cache_state()
|
|
return False # No eviction needed
|
|
|
|
new_node = Node(key, val)
|
|
if len(self.cache) >= self.limit:
|
|
self.evict()
|
|
|
|
if not self.head:
|
|
self.head = self.tail = new_node
|
|
new_node.next = new_node.prev = new_node
|
|
else:
|
|
new_node.prev = self.tail
|
|
new_node.next = self.head
|
|
self.tail.next = new_node
|
|
self.head.prev = new_node
|
|
self.tail = new_node
|
|
|
|
self.cache[key] = new_node
|
|
if not self.hand:
|
|
self.hand = self.head
|
|
#self.print_cache_state()
|
|
return False
|
|
|
|
def invalidate(self, key: str) -> bool:
|
|
if key in self.cache:
|
|
node = self.cache.pop(key)
|
|
if node == self.head:
|
|
self.head = node.next
|
|
if node == self.tail:
|
|
self.tail = node.prev
|
|
if node.next:
|
|
node.next.prev = node.prev
|
|
if node.prev:
|
|
node.prev.next = node.next
|
|
#self.print_cache_state()
|
|
return True
|
|
return False
|
|
|
|
def next_hand(self):
|
|
self.hand = self.hand.next if self.hand.next else self.head
|
|
|
|
def evict(self):
|
|
while self.hand.visited:
|
|
self.hand.visited = False
|
|
self.next_hand()
|
|
obj_to_evict = self.hand
|
|
self.next_hand()
|
|
|
|
if obj_to_evict == self.head:
|
|
self.head = obj_to_evict.next
|
|
if obj_to_evict == self.tail:
|
|
self.tail = obj_to_evict.prev
|
|
if obj_to_evict.next:
|
|
obj_to_evict.next.prev = obj_to_evict.prev
|
|
if obj_to_evict.prev:
|
|
obj_to_evict.prev.next = obj_to_evict.next
|
|
|
|
del self.cache[obj_to_evict.key]
|
|
#self.print_cache_state()
|
|
|
|
# Basic API demo for future testing
|
|
if __name__ == "__main__":
|
|
cache = SeiveCache(3)
|
|
cache.put("a", "1")
|
|
cache.put("b", "2")
|
|
cache.put("c", "3")
|
|
cache.get("a")
|
|
cache.put("d", "4") # Should evict "b"
|
|
assert "b" not in cache.cache, f"Eviction failed, cache contents: {cache.cache.keys()}"
|
|
print("SeiveCache eviction test passed.")
|