Tardigrade Backend: Dependencies

vendor/github.com/spacemonkeygo/monkit/v3/spanbag.go

@@ -0,0 +1,59 @@
+// 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)
+	}
+}