Module map

Available on crate feature map only.

Re-exports of map types and utilities.

This module exports the following types:

• HashMap and HashSet from the standard library or hashbrown crate. The “map-hashbrown” feature can be used to force the use of hashbrown, and is required in no_std environments.
• [IndexMap] and [IndexSet] from the indexmap crate, if the “map-indexmap” feature is enabled.
• The previously-listed hash map types prefixed with Fb. These are type aliases with FixedBytes<N> as the key, and FbBuildHasher as the hasher builder. This hasher is optimized for hashing fixed-size byte arrays, and wraps around the default hasher builder. It performs best when the hasher is fxhash, which is enabled by default with the “map-fxhash” feature.
• The previously-listed hash map types prefixed with Selector, Address, and B256. These use FbBuildHasher with the respective fixed-size byte array as the key. See the previous point for more information.

Unless specified otherwise, the default hasher builder used by these types is DefaultHashBuilder. This hasher prioritizes speed over security. Users who require HashDoS resistance should enable the “rand” feature so that the hasher is initialized using a random seed.

Modules

• hash_map
  A hash map implemented with quadratic probing and SIMD lookup.
• hash_set
  A hash set implemented as a HashMap where the value is ().
• rustc_hash
  A speedy, non-cryptographic hashing algorithm used by rustc.

Structs

• FbBuildHasher
  BuildHasher optimized for hashing fixed-size byte arrays.
• FbHasher
  Hasher optimized for hashing fixed-size byte arrays.
• FxHasher
  A speedy hash algorithm for use within rustc. The hashmap in liballoc by default uses SipHash which isn’t quite as speedy as we want. In the compiler we’re not really worried about DOS attempts, so we use a fast non-cryptographic hash.

Enums

• Entry
  A view into a single entry in a map, which may either be vacant or occupied.

Type Aliases

• AddressHashMap
  HashMap optimized for hashing Address.
• AddressHashSet
  HashSet optimized for hashing Address.
• B256HashMap
  HashMap optimized for hashing B256.
• B256HashSet
  HashSet optimized for hashing B256.
• DefaultHashBuilder
  The default BuildHasher used by HashMap and HashSet.
• DefaultHasher
  The default Hasher used by HashMap and HashSet.
• FbHashMap
  HashMap optimized for hashing fixed-size byte arrays.
• FbHashSet
  HashSet optimized for hashing fixed-size byte arrays.
• FxBuildHasher
  The FxHasher hasher builder.
• HashMap
  A HashMap using the default hasher.
• HashSet
  A HashSet using the default hasher.
• SelectorHashMap
  HashMap optimized for hashing Selector.
• SelectorHashSet
  HashSet optimized for hashing Selector.