Struct BlockLruCache 

struct BlockLruCache {
    map: HashMap<u64, u32>,
    nodes: HashMap<u32, LruNode>,
    head: Option<u32>,
    tail: Option<u32>,
    next_id: u32,
    max_size: usize,
    hits: u64,
    misses: u64,
}

O(1) LRU cache implementation using HashMap + doubly-linked list This implementation uses indices instead of raw pointers to be thread-safe

Fields

map: HashMap<u64, u32>

Map from block number to node ID

nodes: HashMap<u32, LruNode>

Storage for all nodes

head: Option<u32>

Head of doubly-linked list (most recently used)

tail: Option<u32>

Tail of doubly-linked list (least recently used)

next_id: u32

Next available node ID

max_size: usize

Maximum cache size

hits: u64

Cache statistics

misses: u64

Implementations

impl BlockLruCache

fn new(max_size: usize) -> Self

fn get(&mut self, block_num: u64) -> Option<Vec<u8>>

fn move_to_head(&mut self, node_id: u32)

Move node to head of LRU list (O(1))

fn remove_from_list(&mut self, node_id: u32)

Remove node from doubly-linked list (O(1))

fn add_to_head(&mut self, node_id: u32)

Add node to head of list (O(1))

fn insert(&mut self, block_num: u64, block_data: Vec<u8>)

fn remove(&mut self, block_num: u64)

fn len(&self) -> usize

fn get_stats(&self) -> (u64, u64, usize)

Get cache statistics for debugging and performance analysis

fn print_stats(&self, cache_name: &str)

Print cache statistics