densemap

README

densemap

Package densemap provides a generic, dense, ID-based mapping structure for fast, contiguous lookups by integer ID. Unlike Go’s built-in map, densemap stores values in a slice indexed by a bounded integer range [minID, maxID]. This design ensures O(1) access, efficient iteration, and predictable memory usage, making it well-suited for cases where IDs are compact and naturally bounded (e.g., enums, small identifier spaces, event codes).

Install

Run go get github.com/jokruger/densemap

License

This project is licensed under the MIT License. See the LICENSE file for details.

Documentation

Index

• type DenseMap
  • func New[ID Integer, T any](minID, maxID ID) *DenseMap[ID, T]
  • func (dm *DenseMap[ID, T]) Cap() int
  • func (dm *DenseMap[ID, T]) Clear()
  • func (dm *DenseMap[ID, T]) Contains(id ID) bool
  • func (dm *DenseMap[ID, T]) Delete(id ID) error
  • func (dm *DenseMap[ID, T]) First() (ID, *T)
  • func (dm *DenseMap[ID, T]) ForEach(fn func(id ID, value T))
  • func (dm *DenseMap[ID, T]) IsEmpty() bool
  • func (dm *DenseMap[ID, T]) Last() (ID, *T)
  • func (dm *DenseMap[ID, T]) Len() int
  • func (dm *DenseMap[ID, T]) MaxID() ID
  • func (dm *DenseMap[ID, T]) MinID() ID
  • func (dm *DenseMap[ID, T]) Ptr(id ID) *T
  • func (dm *DenseMap[ID, T]) Range(min, max ID, fn func(id ID, value T))
  • func (dm *DenseMap[ID, T]) Set(id ID, value T) error
  • func (dm *DenseMap[ID, T]) Value(id ID) (T, bool)
• type Integer

Types

type DenseMap

type DenseMap[ID Integer, T any] struct {
	// contains filtered or unexported fields
}

DenseMap provides a generic, ID-based lookup structure optimized for fast, contiguous access to values of type T by integer IDs.

func New

func New[ID Integer, T any](minID, maxID ID) *DenseMap[ID, T]

New creates a new DenseMap with a range from minID to maxID (inclusive).

func (*DenseMap[ID, T]) Cap

func (dm *DenseMap[ID, T]) Cap() int

Cap returns the total number of possible values (capacity).

func (*DenseMap[ID, T]) Clear

func (dm *DenseMap[ID, T]) Clear()

Clear resets the DenseMap, removing all set values.

func (*DenseMap[ID, T]) Contains

func (dm *DenseMap[ID, T]) Contains(id ID) bool

Contains returns true if value is set for a given ID.

func (*DenseMap[ID, T]) Delete

func (dm *DenseMap[ID, T]) Delete(id ID) error

Delete removes the value associated with the ID and marks it as invalid.

func (*DenseMap[ID, T]) First

func (dm *DenseMap[ID, T]) First() (ID, *T)

First returns the first set ID and its associated value, or (zeroID, nil) if none are set.

func (*DenseMap[ID, T]) ForEach

func (dm *DenseMap[ID, T]) ForEach(fn func(id ID, value T))

ForEach iterates over all set values and applies the provided function to each value.

func (*DenseMap[ID, T]) IsEmpty

func (dm *DenseMap[ID, T]) IsEmpty() bool

IsEmpty returns true if no elements are set.

func (*DenseMap[ID, T]) Last

func (dm *DenseMap[ID, T]) Last() (ID, *T)

Last returns the last set ID and its associated value, or (zeroID, nil) if none are set.

func (*DenseMap[ID, T]) Len

func (dm *DenseMap[ID, T]) Len() int

Len returns the number of actually set elements.

func (*DenseMap[ID, T]) MaxID

func (dm *DenseMap[ID, T]) MaxID() ID

MaxID returns the maximum ID in the DenseMap.

func (*DenseMap[ID, T]) MinID

func (dm *DenseMap[ID, T]) MinID() ID

MinID returns the minimum ID in the DenseMap.

func (*DenseMap[ID, T]) Ptr

func (dm *DenseMap[ID, T]) Ptr(id ID) *T

Ptr retrieves pointer to the value associated with the ID. Returns *value if set, otherwise nil.

func (*DenseMap[ID, T]) Range

func (dm *DenseMap[ID, T]) Range(min, max ID, fn func(id ID, value T))

Range iterates over a specified range of IDs, applying the provided function to each set value within that range.

func (*DenseMap[ID, T]) Set

func (dm *DenseMap[ID, T]) Set(id ID, value T) error

Set stores a value for the given ID and marks it as valid.

func (*DenseMap[ID, T]) Value

func (dm *DenseMap[ID, T]) Value(id ID) (T, bool)

Value retrieves the value associated with the ID. Returns (value, true) if set, otherwise (zero, false).

type Integer

type Integer interface {
	~int8 | ~int16 | ~int32 | ~uint8 | ~uint16 | ~uint32
}