AdGuardHome/internal/aghalg/ringbuffer.go

103 lines
1.9 KiB
Go

package aghalg
import (
"github.com/AdguardTeam/golibs/errors"
)
// RingBuffer is the implementation of ring buffer data structure.
type RingBuffer[T any] struct {
buf []T
cur int
full bool
}
// NewRingBuffer initializes the new instance of ring buffer. size must be
// greater or equal to zero.
func NewRingBuffer[T any](size int) (rb *RingBuffer[T]) {
if size < 0 {
panic(errors.Error("ring buffer: size must be greater or equal to zero"))
}
return &RingBuffer[T]{
buf: make([]T, size),
}
}
// Append appends an element to the buffer.
func (rb *RingBuffer[T]) Append(e T) {
if len(rb.buf) == 0 {
return
}
rb.buf[rb.cur] = e
rb.cur = (rb.cur + 1) % cap(rb.buf)
if rb.cur == 0 {
rb.full = true
}
}
// Range calls cb for each element of the buffer. If cb returns false it stops.
func (rb *RingBuffer[T]) Range(cb func(T) (cont bool)) {
before, after := rb.splitCur()
for _, e := range before {
if !cb(e) {
return
}
}
for _, e := range after {
if !cb(e) {
return
}
}
}
// ReverseRange calls cb for each element of the buffer in reverse order. If
// cb returns false it stops.
func (rb *RingBuffer[T]) ReverseRange(cb func(T) (cont bool)) {
before, after := rb.splitCur()
for i := len(after) - 1; i >= 0; i-- {
if !cb(after[i]) {
return
}
}
for i := len(before) - 1; i >= 0; i-- {
if !cb(before[i]) {
return
}
}
}
// splitCur splits the buffer in two, before and after current position in
// chronological order. If buffer is not full, after is nil.
func (rb *RingBuffer[T]) splitCur() (before, after []T) {
if len(rb.buf) == 0 {
return nil, nil
}
cur := rb.cur
if !rb.full {
return rb.buf[:cur], nil
}
return rb.buf[cur:], rb.buf[:cur]
}
// Len returns a length of the buffer.
func (rb *RingBuffer[T]) Len() (l int) {
if !rb.full {
return rb.cur
}
return cap(rb.buf)
}
// Clear clears the buffer.
func (rb *RingBuffer[T]) Clear() {
rb.full = false
rb.cur = 0
}