blob: baca2afe8c2c11eac5e7d9900a17557dcfb12ce7 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package ringbuffer contains a fixed-size concurrency-safe generic ring
// buffer.
package ringbuffer
import "sync"
// New creates a new RingBuffer containing at most max items.
func New[T any](max int) *RingBuffer[T] {
return &RingBuffer[T]{
max: max,
}
}
// RingBuffer is a concurrency-safe ring buffer.
type RingBuffer[T any] struct {
mu sync.Mutex
pos int
buf []T
max int
}
// Add appends a new item to the RingBuffer, possibly overwriting the oldest
// item in the buffer if it is already full.
//
// It does nothing if rb is nil.
func (rb *RingBuffer[T]) Add(t T) {
if rb == nil {
return
}
rb.mu.Lock()
defer rb.mu.Unlock()
if len(rb.buf) < rb.max {
rb.buf = append(rb.buf, t)
} else {
rb.buf[rb.pos] = t
rb.pos = (rb.pos + 1) % rb.max
}
}
// GetAll returns a copy of all the entries in the ring buffer in the order they
// were added.
//
// It returns nil if rb is nil.
func (rb *RingBuffer[T]) GetAll() []T {
if rb == nil {
return nil
}
rb.mu.Lock()
defer rb.mu.Unlock()
out := make([]T, len(rb.buf))
for i := range len(rb.buf) {
x := (rb.pos + i) % rb.max
out[i] = rb.buf[x]
}
return out
}
// Len returns the number of elements in the ring buffer. Note that this value
// could change immediately after being returned if a concurrent caller
// modifies the buffer.
func (rb *RingBuffer[T]) Len() int {
if rb == nil {
return 0
}
rb.mu.Lock()
defer rb.mu.Unlock()
return len(rb.buf)
}
// Clear will empty the ring buffer.
func (rb *RingBuffer[T]) Clear() {
rb.mu.Lock()
defer rb.mu.Unlock()
rb.pos = 0
rb.buf = nil
}
|
