gods/maps/treemap/treemap.go

/*
Copyright (c) 2015, Emir Pasic
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

// Implementation of order map backed by red-black tree.
// Elements are ordered by key in the map.
// Structure is not thread safe.
// References: http://en.wikipedia.org/wiki/Associative_array

package treemap

import (
	"github.com/emirpasic/gods/containers"
	"github.com/emirpasic/gods/maps"
	rbt "github.com/emirpasic/gods/trees/redblacktree"
	"github.com/emirpasic/gods/utils"
)

func assertInterfaceImplementation() {
	var _ maps.Map = (*Map)(nil)
	var _ containers.EnumerableWithKey = (*Map)(nil)
	var _ containers.IteratorWithKey = (*Iterator)(nil)
}

type Map struct {
	tree *rbt.Tree
}

// Instantiates a tree map with the custom comparator.
func NewWith(comparator utils.Comparator) *Map {
	return &Map{tree: rbt.NewWith(comparator)}
}

// Instantiates a tree map with the IntComparator, i.e. keys are of type int.
func NewWithIntComparator() *Map {
	return &Map{tree: rbt.NewWithIntComparator()}
}

// Instantiates a tree map with the StringComparator, i.e. keys are of type string.
func NewWithStringComparator() *Map {
	return &Map{tree: rbt.NewWithStringComparator()}
}

// Inserts key-value pair into the map.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Put(key interface{}, value interface{}) {
	m.tree.Put(key, value)
}

// Searches the element in the map by key and returns its value or nil if key is not found in tree.
// Second return parameter is true if key was found, otherwise false.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Get(key interface{}) (value interface{}, found bool) {
	return m.tree.Get(key)
}

// Remove the element from the map by key.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Remove(key interface{}) {
	m.tree.Remove(key)
}

// Returns true if map does not contain any elements
func (m *Map) Empty() bool {
	return m.tree.Empty()
}

// Returns number of elements in the map.
func (m *Map) Size() int {
	return m.tree.Size()
}

// Returns all keys in-order
func (m *Map) Keys() []interface{} {
	return m.tree.Keys()
}

// Returns all values in-order based on the key.
func (m *Map) Values() []interface{} {
	return m.tree.Values()
}

// Removes all elements from the map.
func (m *Map) Clear() {
	m.tree.Clear()
}

// Returns the minimum key and its value from the tree map.
// Returns nil, nil if map is empty.
func (m *Map) Min() (key interface{}, value interface{}) {
	if node := m.tree.Left(); node != nil {
		return node.Key, node.Value
	}
	return nil, nil
}

// Returns the maximum key and its value from the tree map.
// Returns nil, nil if map is empty.
func (m *Map) Max() (key interface{}, value interface{}) {
	if node := m.tree.Right(); node != nil {
		return node.Key, node.Value
	}
	return nil, nil
}

type Iterator struct {
	iterator rbt.Iterator
}

// Returns a stateful iterator whose elements are key/value pairs.
func (m *Map) Iterator() Iterator {
	return Iterator{iterator: m.tree.Iterator()}
}

// 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().
// Modifies the state of the iterator.
func (iterator *Iterator) Next() bool {
	return iterator.iterator.Next()
}

// Returns the current element's value.
// Does not modify the state of the iterator.
func (iterator *Iterator) Value() interface{} {
	return iterator.iterator.Value()
}

// Returns the current element's key.
// Does not modify the state of the iterator.
func (iterator *Iterator) Key() interface{} {
	return iterator.iterator.Key()
}

// Calls the given function once for each element, passing that element's key and value.
func (m *Map) Each(f func(key interface{}, value interface{})) {
	iterator := m.Iterator()
	for iterator.Next() {
		f(iterator.Key(), iterator.Value())
	}
}

// Invokes the given function once for each element and returns a container
// containing the values returned by the given function as key/value pairs.
func (m *Map) Map(f func(key1 interface{}, value1 interface{}) (interface{}, interface{})) *Map {
	newMap := &Map{tree: rbt.NewWith(m.tree.Comparator)}
	iterator := m.Iterator()
	for iterator.Next() {
		key2, value2 := f(iterator.Key(), iterator.Value())
		newMap.Put(key2, value2)
	}
	return newMap
}

// Returns a new container containing all elements for which the given function returns a true value.
func (m *Map) Select(f func(key interface{}, value interface{}) bool) *Map {
	newMap := &Map{tree: rbt.NewWith(m.tree.Comparator)}
	iterator := m.Iterator()
	for iterator.Next() {
		if f(iterator.Key(), iterator.Value()) {
			newMap.Put(iterator.Key(), iterator.Value())
		}
	}
	return newMap
}

// Passes each element of the container to the given function and
// returns true if the function ever returns true for any element.
func (m *Map) Any(f func(key interface{}, value interface{}) bool) bool {
	iterator := m.Iterator()
	for iterator.Next() {
		if f(iterator.Key(), iterator.Value()) {
			return true
		}
	}
	return false
}

// Passes each element of the container to the given function and
// returns true if the function returns true for all elements.
func (m *Map) All(f func(key interface{}, value interface{}) bool) bool {
	iterator := m.Iterator()
	for iterator.Next() {
		if !f(iterator.Key(), iterator.Value()) {
			return false
		}
	}
	return true
}

// Passes each element of the container to the given function and returns
// the first (key,value) for which the function is true or nil,nil otherwise if no element
// matches the criteria.
func (m *Map) Find(f func(key interface{}, value interface{}) bool) (interface{}, interface{}) {
	iterator := m.Iterator()
	for iterator.Next() {
		if f(iterator.Key(), iterator.Value()) {
			return iterator.Key(), iterator.Value()
		}
	}
	return nil, nil
}

func (m *Map) String() string {
	str := "TreeMap\n"
	str += m.tree.String()
	return str
}