Struct CacheTable

pub struct CacheTable<T: Copy + Clone + PartialEq + PartialOrd> { /* private fields */ }

Store a cache of entries, each with an associated hash.

Implementations

impl<T: Copy + Clone + PartialEq + PartialOrd> CacheTable<T>

pub fn new(size: usize, default: T) -> CacheTable<T>

Create a new CacheTable with each associated entry initialized with a hash of ‘0’ Note: You must pass in a size where only 1 bit is set. (AKA: 2, 4, 8, 16, 1024, 65536, etc.) Panics when size is invalid.

pub fn get(&self, hash: u64) -> Option<T>

Get a particular entry with the hash specified

pub fn add(&mut self, hash: u64, entry: T)

Add (or overwrite) an entry with the associated hash

pub fn replace_if<F: Fn(T) -> bool>(&mut self, hash: u64, entry: T, replace: F)

Replace an entry in the hash table with a user-specified replacement policy specified by replace. The replace closure is called with the previous entry occupying the hash table slot, and returns true or false to specify whether the entry should be replaced. Note that the previous entry may not have the same hash, but merely be the default initialization or a hash collision with hash.

use candidate::CacheTable;


let mut table: CacheTable<char> = CacheTable::new(256, 'a');

assert_eq!(table.get(5), None);
// Note that 'a' is the default initialization value.
table.replace_if(5, 'b', |old_entry| old_entry != 'a');
assert_eq!(table.get(5), None);
table.replace_if(5, 'c', |old_entry| old_entry == 'a');
assert_eq!(table.get(5), Some('c'));
table.replace_if(5, 'd', |old_entry| old_entry == 'c');
assert_eq!(table.get(5), Some('d'));