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// Copyright (c) 2015, Emir Pasic. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package hashset implements a set backed by a hash table.
//
// Structure is not thread safe.
//
// References: http://en.wikipedia.org/wiki/Set_%28abstract_data_type%29
package hashset
import (
"fmt"
"github.com/emirpasic/gods/sets"
"strings"
)
func assertSetImplementation() {
var _ sets.Set = (*Set)(nil)
}
// Set holds elements in go's native map
type Set struct {
items map[interface{}]struct{}
}
var itemExists = struct{}{}
// New instantiates a new empty set
func New() *Set {
return &Set{items: make(map[interface{}]struct{})}
}
// Add adds the items (one or more) to the set.
func (set *Set) Add(items ...interface{}) {
for _, item := range items {
set.items[item] = itemExists
}
}
// Remove removes the items (one or more) from the set.
func (set *Set) Remove(items ...interface{}) {
for _, item := range items {
delete(set.items, item)
}
}
// Contains check if items (one or more) are present in the set.
// All items have to be present in the set for the method to return true.
// Returns true if no arguments are passed at all, i.e. set is always superset of empty set.
func (set *Set) Contains(items ...interface{}) bool {
for _, item := range items {
if _, contains := set.items[item]; !contains {
return false
}
}
return true
}
// Empty returns true if set does not contain any elements.
func (set *Set) Empty() bool {
return set.Size() == 0
}
// Size returns number of elements within the set.
func (set *Set) Size() int {
return len(set.items)
}
// Clear clears all values in the set.
func (set *Set) Clear() {
set.items = make(map[interface{}]struct{})
}
// Values returns all items in the set.
func (set *Set) Values() []interface{} {
values := make([]interface{}, set.Size())
count := 0
for item := range set.items {
values[count] = item
count++
}
return values
}
// String returns a string representation of container
func (set *Set) String() string {
str := "HashSet\n"
items := []string{}
for k := range set.items {
items = append(items, fmt.Sprintf("%v", k))
}
str += strings.Join(items, ", ")
return str
}