Crate kollect

🗂️ kollect

A set of collections optimized for game development usecases.

Provided Collections

• LinearMap, useful when you want a collection that behaves as a key-value map but you will only ever have up to a few tens of elements. For small numbers of elements and small size of contained key/value types, this will likely be faster and take up less memory than other map types, but its random access operations have O(len) complexity rather than O(1) as with hash-based maps.

• UnorderedMap, useful when you want a general-purpose key-value map, you plan to do random access lookup by key more frequently than iteration of the contained elements, and you don’t care about order of those elements.

• OrderedMap, useful when you want a key-value map including a set order of element pairs, or when you plan to iterate over the contained elements more frequently than you do random access lookup by key.

• LinearSet, useful in the same situation as LinearMap but when you’re operating on a set of values rather than a map.

• UnorderedSet, useful when you want set-like operations, will do more random access than iteration, and will fill with a medium to high number of elements.

• OrderedSet, useful when you want set-like operations and need a defined order of elements, or you plan to iterate over the contained elements more frequently than do random access lookup on them.

Usage table

Number of elements	Access pattern	Need defined order	Choose
Less than ~128	Any	Any	LinearMap/LinearSet
More than ~128	More Random Access	No	UnorderedMap/UnorderedSet
More than ~128	More Iteration	No	OrderedMap/OrderedSet
More than ~128	Any	Yes	OrderedMap/OrderedSet

Specialized hashers

The specialized_hashers module contains some helpful specialized hasher variants that can speed up your hash-based collections when you have knowledge about the keys/elements being used.

For example, if your keys in a map or set are small and primitive-integer-only, then you may want to use a BuildPrimitiveHasher-based alias of one of the hash-based collections (UnorderedPrimitiveMap, etc.).

Alternatively, if you are keying a map or creating a collection of elements which are themselves already a hash value (or which otherwise qualify as NoHashable), then you may want to use one of the BuildNoHashHasher-based aliases of one of the hash-based collections (UnorderedNoHashMap, etc.).

serde_as_seq for maps

When the serde feature is enabled, there are adapters usable with #[serde(with = "path::to::module")] at kollect::some_map::serde_as_seq which will serialize and deserialize those maps as sequences of (k, v) pair elements rather than as native serde Maps. This is useful with JSON because JSON maps can only have string keys, and if you try to serialize a map to JSON which has a key type that can’t be serialized as a string, the serde JSON impl will simply panic at runtime. Using serde_as_seq will circumvent this issue and allow you to serialize a wider range of key types.

Feature flags

kollect uses a set of feature flags to optionally reduce the number of dependencies.

The following optional features are available:

Name	Description	Default?
speedy	Enables speedy support for most types	No
serde	Enables serde support for most types	No

Modules

• linear_map
  A key-value map specialized for small numbers of elements, implemented by searching linearly in a vector.
• linear_set
  A set specialized for small numbers of elements, implemented by searching linearly in a vector.
• ordered_map
  Provides a fast, general purpose, key-value map with a defined order of elements.
• ordered_set
  Provides a fast, general purpose, deduplicated set type *with a defined order of elements.
• specialized_hashers
  Contains BuildHashers (which can be used with other hash-based collections provided by this crate) specialized for specific types of elements or situations.
• unordered_map
  Provides a fast, general purpose, key-value map with no defined order of elements
• unordered_set
  Provides a fast, general purpose, deduplicated set type with no defined order of elements

Structs

• LinearMap
  A map implemented by searching linearly in a vector.
• LinearSet
  An implementation of a set using the underlying representation of a LinearMap where the value is (). This means the set is effectively a Vec with operations optimized for working on items that function as a set.
• OrderedMap
  A key-to-value map that has a specified order of contained elements.
• OrderedSet
  A set that has a specified order of contained elements.
• UnorderedMap
  A key-to-value map that does not have a specified order of contained elements.
• UnorderedSet
  A deduplicated set that does not have a specified order of contained elements.

Traits

• NoHashable
  Used to mark a type as able to be used with a NoHashHasher-based hash map or hash set.

Type Aliases

• OrderedNoHashMap
  Type-alias of OrderedMap that is useful when you are using keys that are NoHashable
• OrderedNoHashSet
  Type-alias of OrderedSet that is useful when you are using elements that are NoHashable
• OrderedPrimitiveMap
  Type-alias of OrderedMap that is useful when you are using small keys consisting of only a few primitive types.
• OrderedPrimitiveSet
  Type-alias of OrderedSet that is useful when you are using small elements consisting of only a few primitive types.
• UnorderedNoHashMap
  Type-alias of UnorderedMap that is useful when you are using keys that are NoHashable
• UnorderedNoHashSet
  Type-alias of UnorderedSet that is useful when you are using elements that are NoHashable
• UnorderedPrimitiveMap
  Type-alias of UnorderedMap that is useful when you are using small keys consisting of only a few primitive types.
• UnorderedPrimitiveSet
  Type-alias of UnorderedSet that is useful when you are using small elements consisting of only a few primitive types.