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// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package maps defines various functions useful with maps of any type.
//
// This package does not have any special handling for non-reflexive keys
// (keys k where k != k), such as floating-point NaNs.
package maps
import (
_ "unsafe"
)
// Equal reports whether two maps contain the same key/value pairs.
// Values are compared using ==.
func Equal[M1, M2 ~map[K]V, K, V comparable](m1 M1, m2 M2) bool {
if len(m1) != len(m2) {
return false
}
for k, v1 := range m1 {
if v2, ok := m2[k]; !ok || v1 != v2 {
return false
}
}
return true
}
// EqualFunc is like Equal, but compares values using eq.
// Keys are still compared with ==.
func EqualFunc[M1 ~map[K]V1, M2 ~map[K]V2, K comparable, V1, V2 any](m1 M1, m2 M2, eq func(V1, V2) bool) bool {
if len(m1) != len(m2) {
return false
}
for k, v1 := range m1 {
if v2, ok := m2[k]; !ok || !eq(v1, v2) {
return false
}
}
return true
}
// clone is implemented in the runtime package.
//
//go:linkname clone maps.clone
func clone(m any) any
// Clone returns a copy of m. This is a shallow clone:
// the new keys and values are set using ordinary assignment.
func Clone[M ~map[K]V, K comparable, V any](m M) M {
// Preserve nil in case it matters.
if m == nil {
return nil
}
return clone(m).(M)
}
// Copy copies all key/value pairs in src adding them to dst.
// When a key in src is already present in dst,
// the value in dst will be overwritten by the value associated
// with the key in src.
func Copy[M1 ~map[K]V, M2 ~map[K]V, K comparable, V any](dst M1, src M2) {
for k, v := range src {
dst[k] = v
}
}
// DeleteFunc deletes any key/value pairs from m for which del returns true.
func DeleteFunc[M ~map[K]V, K comparable, V any](m M, del func(K, V) bool) {
for k, v := range m {
if del(k, v) {
delete(m, k)
}
}
}