gotosocial/internal/util/unique.go

74 lines
1.9 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package util
// Set represents a hashmap of only keys,
// useful for deduplication / key checking.
type Set[T comparable] map[T]struct{}
// ToSet creates a Set[T] from given values,
// noting that this does not maintain any order.
func ToSet[T comparable](in []T) Set[T] {
set := make(Set[T], len(in))
for _, v := range in {
set[v] = struct{}{}
}
return set
}
// FromSet extracts the values from set to slice,
// noting that this does not maintain any order.
func FromSet[T comparable](in Set[T]) []T {
out := make([]T, len(in))
var i int
for v := range in {
out[i] = v
i++
}
return out
}
// In returns input slice filtered to
// only contain those in receiving set.
func (s Set[T]) In(vs []T) []T {
out := make([]T, 0, len(vs))
for _, v := range vs {
if _, ok := s[v]; ok {
out = append(out, v)
}
}
return out
}
// NotIn is the functional inverse of In().
func (s Set[T]) NotIn(vs []T) []T {
out := make([]T, 0, len(vs))
for _, v := range vs {
if _, ok := s[v]; !ok {
out = append(out, v)
}
}
return out
}
// Has returns if value is in Set.
func (s Set[T]) Has(v T) bool {
_, ok := s[v]
return ok
}