Double Map

Like a [HashMap], but allows you to use two different keys to the same value/data.

Sometimes during development, it may be necessary to have a data structure like a HashMap but with two different keys refiring to the same data.

For example, if you have some data with a unique ID and a name, then you create a structure that contains the name, and store it in a normal HashMap using the unique ID as the key. However, finding the element throughout the name will be performed with O(n) time. The same is true for the reverse case.

This crate try to resolve this contradiction by providing a DHashMap structure - a map where you can add, lookup and remove elements using either the first key of type K1 or the second key of type K2.

Internally, it uses two maps: the first is of type HashMap<K1, (K2, V)> and the second is of type HashMap<K2, K1>. Using two HashMap's insides instead one brings to the performance and memory penalty.

It is recommended to use the first key of type K1 of quick access to the data, because indexing by the second key of type K2 requires two HashMap lookups.

Change log

Current Status

Double Map is in active development. The design goal is implementing the whole [HashMap] interface. Look at Change log for more infomation.

Methods

• [x] new: Done sinse v0.1.0
• [x] with_capacity: Done sinse v0.1.0
• [x] with_hasher: Done sinse v0.1.0
• [x] with_capacity_and_hasher: Done sinse v0.1.0
• [x] capacity: Done sinse v0.1.0
• [ ] keys: Under development
• [ ] into_keys: Under development
• [ ] values: Under development
• [ ] values_mut: Under development
• [ ] into_values: Under development
• [ ] iter Under: development
• [ ] iter_mut: Under development
• [x] len: Done sinse v0.1.0
• [x] is_empty: Done sinse v0.1.0
• [ ] drain: Under development
• [ ] drain_filter: Under development
• [ ] retain: Under development
• [x] clear: Done sinse v0.1.0
• [x] hasher: Done sinse v0.1.0
• [x] reserve: Done sinse v0.1.0
• [x] try_reserve: Done sinse v0.1.0
• [x] shrink_to_fit: Done sinse v0.1.0
• [x] shrink_to: Done sinse v0.1.0
• [x] entry: Done sinse v0.1.0
• [x] get: Done sinse v0.1.0 (get_key1 and get_key2 methods)
• [ ] get_key_value: Under development
• [ ] contains_key: Under development
• [x] get_mut: Done sinse v0.1.0 (get_mut_key1 and get_mut_key2 methods)
• [x] insert: Done sinse v0.1.0 (insert_unchecked and insert methods)
• [x] try_insert: Done sinse v0.1.0
• [x] remove: Done sinse v0.1.0 (remove_key1 and remove_key2 methods)
• [ ] remove_entry: Under development
• [ ] raw_entry_mut: Under development
• [ ] raw_entry: Under development

Trait Implementations

• [ ] Clone: Under development
• [ ] Debug: Under development
• [ ] Default: Under development
• [ ] Extend: Under development
• [ ] From: Under development
• [ ] FromIterator: Under development
• [ ] Index: Under development
• [ ] IntoIterator: Under development
• [ ] PartialEq: Under development

License

Licensed under Apache License, Version 2.0, (LICENSE or https://www.apache.org/licenses/LICENSE-2.0) at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions.