README
¶
BTree
Good performed algorithm in case of searching data inside. Thead-unsafe implementation.
Documentation
¶
Overview ¶
Package btree provides a B-tree for ordered key-value storage with configurable order.
NOT safe for concurrent use. Callers must synchronize access externally.
Index ¶
- Constants
- Variables
- type Entry
- type Iterator
- func (iterator *Iterator[K, V]) Begin()
- func (iterator *Iterator[K, V]) End()
- func (iterator *Iterator[K, V]) First() bool
- func (iterator *Iterator[K, V]) Key() K
- func (iterator *Iterator[K, V]) Last() bool
- func (iterator *Iterator[K, V]) Next() bool
- func (iterator *Iterator[K, V]) Prev() bool
- func (iterator *Iterator[K, V]) Value() any
- type Node
- type Tree
- func (tree *Tree[K, V]) Clear()
- func (tree *Tree[K, V]) Copy() *Tree[K, V]
- func (tree *Tree[K, V]) Empty() bool
- func (tree *Tree[K, V]) Get(key K) (value V, found bool, err error)
- func (tree *Tree[K, V]) Height() int
- func (tree *Tree[K, V]) Iterator() Iterator[K, V]
- func (tree *Tree[K, V]) Keys() []K
- func (tree *Tree[K, V]) Left() *Node[K, V]
- func (tree *Tree[K, V]) LeftKey() any
- func (tree *Tree[K, V]) LeftValue() any
- func (tree *Tree[K, V]) Len() int
- func (tree *Tree[K, V]) Put(key K, value V) (err error)
- func (tree *Tree[K, V]) Remove(key K) (err error)
- func (tree *Tree[K, V]) Right() *Node[K, V]
- func (tree *Tree[K, V]) RightKey() any
- func (tree *Tree[K, V]) RightValue() any
- func (tree *Tree[K, V]) String() string
- func (tree *Tree[K, V]) Values() []any
Examples ¶
Constants ¶
const (
MinOrder = 3
)
MinOrder is the minimum allowed order (maximum number of children) for a B-tree.
Variables ¶
var (
ErrInvalidOrder = errors.New("invalid order, should be at least 3")
)
All kind of errors
Functions ¶
This section is empty.
Types ¶
type Entry ¶
type Entry[K comparable, V any] struct { Key K Value V }
Entry represents the key-value pair contained within nodes
type Iterator ¶
type Iterator[K comparable, V any] struct { // contains filtered or unexported fields }
Iterator holding the iterator's state
func (*Iterator[K, V]) Begin ¶
func (iterator *Iterator[K, V]) Begin()
Begin resets the iterator to its initial state (one-before-first) Call Next() to fetch the first element if any.
func (*Iterator[K, V]) End ¶
func (iterator *Iterator[K, V]) End()
End moves the iterator past the last element (one-past-the-end). Call Prev() to fetch the last element if any.
func (*Iterator[K, V]) First ¶
First moves the iterator to the first element and returns true if there was a first element in the container. If First() returns true, then first element's key and value can be retrieved by Key() and Value(). Modifies the state of the iterator
func (*Iterator[K, V]) Key ¶
func (iterator *Iterator[K, V]) Key() K
Key returns the current element's key. Does not modify the state of the iterator.
func (*Iterator[K, V]) Last ¶
Last moves the iterator to the last element and returns true if there was a last element in the container. If Last() returns true, then last element's key and value can be retrieved by Key() and Value(). Modifies the state of the iterator.
func (*Iterator[K, V]) Next ¶
Next moves the iterator to the next element and returns true if there was a next element in the container. If Next() returns true, then next element's key and value can be retrieved by Key() and Value(). If Next() was called for the first time, then it will point the iterator to the first element if it exists. Modifies the state of the iterator.
type Node ¶
type Node[K comparable, V any] struct { Parent *Node[K, V] Entries []*Entry[K, V] // Contained keys in node Children []*Node[K, V] // Children nodes }
Node is a single element within the tree
type Tree ¶
type Tree[K comparable, V any] struct { Root *Node[K, V] // Root node Comparator comparator.Comparator // Key comparator // contains filtered or unexported fields }
Tree holds elements of the B-tree.
func NewWith ¶
func NewWith[K comparable, V any](order int, comparator comparator.Comparator) (*Tree[K, V], error)
NewWith instantiates a B-tree with the order (maximum number of children) and a custom key comparator.
func NewWithIntComparator ¶
NewWithIntComparator instantiates a B-tree with the order (maximum number of children) and the IntComparator, i.e. keys are of type int.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, err := btree.NewWithIntComparator(3)
if err != nil {
panic(err)
}
_ = tree.Put(1, "one")
_ = tree.Put(2, "two")
_ = tree.Put(3, "three")
fmt.Println(tree.Len())
}
Output: 3
func NewWithStringComparator ¶
NewWithStringComparator instantiates a B-tree with the order (maximum number of children) and the StringComparator, i.e. keys are of type string.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, err := btree.NewWithStringComparator(3)
if err != nil {
panic(err)
}
_ = tree.Put("b", "banana")
_ = tree.Put("a", "apple")
_ = tree.Put("c", "cherry")
fmt.Println(tree.Keys())
}
Output: [a b c]
func (*Tree[K, V]) Copy ¶
Copy returns a deep copy of the tree. The new tree shares the same comparator but has independent nodes. Keys and values are shallow-copied.
func (*Tree[K, V]) Get ¶
Get searches the node in the tree by key and returns its value or the zero value if not found. Second return parameter is true if key was found, otherwise false. Returns an error if the key type does not match the comparator.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, _ := btree.NewWithIntComparator(3)
_ = tree.Put(1, "one")
value, found, _ := tree.Get(1)
fmt.Println(value, found)
value, found, _ = tree.Get(99)
fmt.Println(value, found)
}
Output: one true <nil> false
func (*Tree[K, V]) Iterator ¶
Iterator returns a stateful iterator whose elements are key/value pairs.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, _ := btree.NewWithIntComparator(3)
_ = tree.Put(3, "three")
_ = tree.Put(1, "one")
_ = tree.Put(2, "two")
it := tree.Iterator()
for it.Next() {
fmt.Printf("%d=%v ", it.Key(), it.Value())
}
fmt.Println()
}
Output: 1=one 2=two 3=three
func (*Tree[K, V]) Put ¶
Put inserts key-value pair node into the tree. If key already exists, then its value is updated with the new value. Returns an error if the key type does not match the comparator.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, _ := btree.NewWithIntComparator(3)
_ = tree.Put(3, "three")
_ = tree.Put(1, "one")
_ = tree.Put(2, "two")
fmt.Println(tree.Keys())
}
Output: [1 2 3]
func (*Tree[K, V]) Remove ¶
Remove removes the node from the tree by key. Returns an error if the key type does not match the comparator.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/btree"
)
func main() {
tree, _ := btree.NewWithIntComparator(3)
_ = tree.Put(1, "one")
_ = tree.Put(2, "two")
_ = tree.Put(3, "three")
_ = tree.Remove(2)
fmt.Println(tree.Keys())
}
Output: [1 3]
func (*Tree[K, V]) RightValue ¶
RightValue returns the right-most value or nil if tree is empty.
Source Files