1 files changed, 77 insertions, 0 deletions
diff --git a/vendor/maunium.net/go/mautrix/util/ringbuffer.go b/vendor/maunium.net/go/mautrix/util/ringbuffer.go
new file mode 100644
index 00000000..ddb4c79f
--- /dev/null
+++ b/vendor/maunium.net/go/mautrix/util/ringbuffer.go
@@ -0,0 +1,77 @@
+// Copyright (c) 2023 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package util
+
+import (
+	"sync"
+)
+
+type pair[Key comparable, Value any] struct {
+	Key   Key
+	Value Value
+}
+
+type RingBuffer[Key comparable, Value any] struct {
+	ptr  int
+	data []pair[Key, Value]
+	lock sync.RWMutex
+}
+
+func NewRingBuffer[Key comparable, Value any](size int) *RingBuffer[Key, Value] {
+	return &RingBuffer[Key, Value]{
+		data: make([]pair[Key, Value], size),
+	}
+}
+
+func (rb *RingBuffer[Key, Value]) Contains(val Key) bool {
+	_, ok := rb.Get(val)
+	return ok
+}
+
+func (rb *RingBuffer[Key, Value]) Get(key Key) (val Value, found bool) {
+	rb.lock.RLock()
+	end := rb.ptr
+	for i := clamp(end-1, len(rb.data)); i != end; i = clamp(i-1, len(rb.data)) {
+		if rb.data[i].Key == key {
+			val = rb.data[i].Value
+			found = true
+			break
+		}
+	}
+	rb.lock.RUnlock()
+	return
+}
+
+func (rb *RingBuffer[Key, Value]) Replace(key Key, val Value) bool {
+	rb.lock.Lock()
+	defer rb.lock.Unlock()
+	end := rb.ptr
+	for i := clamp(end-1, len(rb.data)); i != end; i = clamp(i-1, len(rb.data)) {
+		if rb.data[i].Key == key {
+			rb.data[i].Value = val
+			return true
+		}
+	}
+	return false
+}
+
+func (rb *RingBuffer[Key, Value]) Push(key Key, val Value) {
+	rb.lock.Lock()
+	rb.data[rb.ptr] = pair[Key, Value]{Key: key, Value: val}
+	rb.ptr = (rb.ptr + 1) % len(rb.data)
+	rb.lock.Unlock()
+}
+
+func clamp(index, len int) int {
+	if index < 0 {
+		return len + index
+	} else if index >= len {
+		return len - index
+	} else {
+		return index
+	}
+}