rclone/vendor/github.com/spacemonkeygo/monkit/v3/spanbag.go
2020-05-12 15:56:50 +00:00

60 lines
1.4 KiB
Go

// Copyright (C) 2015 Space Monkey, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package monkit
// spanBag is a bag data structure (can add 0 or more references to a span,
// where every add needs to be matched with an equivalent remove). spanBag has
// a fast path for dealing with cases where the bag only has one element (the
// common case). spanBag is not threadsafe
type spanBag struct {
first *Span
rest map[*Span]int32
}
func (b *spanBag) Add(s *Span) {
if b.first == nil {
b.first = s
return
}
if b.rest == nil {
b.rest = map[*Span]int32{}
}
b.rest[s] += 1
}
func (b *spanBag) Remove(s *Span) {
if b.first == s {
b.first = nil
return
}
// okay it must be in b.rest
count := b.rest[s]
if count <= 1 {
delete(b.rest, s)
} else {
b.rest[s] = count - 1
}
}
// Iterate returns all elements
func (b *spanBag) Iterate(cb func(*Span)) {
if b.first != nil {
cb(b.first)
}
for s := range b.rest {
cb(s)
}
}