AdGuardHome/internal/aghalg/aghalg.go

76 lines
1.8 KiB
Go

// Package aghalg contains common generic algorithms and data structures.
//
// TODO(a.garipov): Update to use type parameters in Go 1.18.
package aghalg
import (
"fmt"
"sort"
)
// comparable is an alias for interface{}. Values passed as arguments of this
// type alias must be comparable.
//
// TODO(a.garipov): Remove in Go 1.18.
type comparable = interface{}
// UniqChecker allows validating uniqueness of comparable items.
type UniqChecker map[comparable]int64
// Add adds a value to the validator. v must not be nil.
func (uc UniqChecker) Add(elems ...comparable) {
for _, e := range elems {
uc[e]++
}
}
// Merge returns a checker containing data from both uc and other.
func (uc UniqChecker) Merge(other UniqChecker) (merged UniqChecker) {
merged = make(UniqChecker, len(uc)+len(other))
for elem, num := range uc {
merged[elem] += num
}
for elem, num := range other {
merged[elem] += num
}
return merged
}
// Validate returns an error enumerating all elements that aren't unique.
// isBefore is an optional sorting function to make the error message
// deterministic.
func (uc UniqChecker) Validate(isBefore func(a, b comparable) (less bool)) (err error) {
var dup []comparable
for elem, num := range uc {
if num > 1 {
dup = append(dup, elem)
}
}
if len(dup) == 0 {
return nil
}
if isBefore != nil {
sort.Slice(dup, func(i, j int) (less bool) {
return isBefore(dup[i], dup[j])
})
}
return fmt.Errorf("duplicated values: %v", dup)
}
// IntIsBefore is a helper sort function for UniqChecker.Validate.
// a and b must be of type int.
func IntIsBefore(a, b comparable) (less bool) {
return a.(int) < b.(int)
}
// StringIsBefore is a helper sort function for UniqChecker.Validate.
// a and b must be of type string.
func StringIsBefore(a, b comparable) (less bool) {
return a.(string) < b.(string)
}