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// Copyright 2014 Canonical Ltd.
// Licensed under the LGPLv3, see LICENCE file for details.
package set
import (
"sort"
)
// Ints represents the classic "set" data structure, and contains ints.
type Ints map[int]bool
// NewInts creates and initializes an Ints and populates it with
// initial values as specified in the parameters.
func NewInts(initial ...int) Ints {
result := make(Ints)
for _, value := range initial {
result.Add(value)
}
return result
}
// Size returns the number of elements in the set.
func (is Ints) Size() int {
return len(is)
}
// IsEmpty is true for empty or uninitialized sets.
func (is Ints) IsEmpty() bool {
return len(is) == 0
}
// Add puts a value into the set.
func (is Ints) Add(value int) {
if is == nil {
panic("uninitalised set")
}
is[value] = true
}
// Remove takes a value out of the set. If value wasn't in the set to start
// with, this method silently succeeds.
func (is Ints) Remove(value int) {
delete(is, value)
}
// Contains returns true if the value is in the set, and false otherwise.
func (is Ints) Contains(value int) bool {
_, exists := is[value]
return exists
}
// Values returns an unordered slice containing all the values in the set.
func (is Ints) Values() []int {
result := make([]int, len(is))
i := 0
for key := range is {
result[i] = key
i++
}
return result
}
// SortedValues returns an ordered slice containing all the values in the set.
func (is Ints) SortedValues() []int {
values := is.Values()
sort.Ints(values)
return values
}
// Union returns a new Ints representing a union of the elments in the
// method target and the parameter.
func (is Ints) Union(other Ints) Ints {
result := make(Ints)
// Use the internal map rather than going through the friendlier functions
// to avoid extra allocation of slices.
for value := range is {
result[value] = true
}
for value := range other {
result[value] = true
}
return result
}
// Intersection returns a new Ints representing a intersection of the elments in the
// method target and the parameter.
func (is Ints) Intersection(other Ints) Ints {
result := make(Ints)
// Use the internal map rather than going through the friendlier functions
// to avoid extra allocation of slices.
for value := range is {
if other.Contains(value) {
result[value] = true
}
}
return result
}
// Difference returns a new Ints representing all the values in the
// target that are not in the parameter.
func (is Ints) Difference(other Ints) Ints {
result := make(Ints)
// Use the internal map rather than going through the friendlier functions
// to avoid extra allocation of slices.
for value := range is {
if !other.Contains(value) {
result[value] = true
}
}
return result
}
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