ring.go

package ring

type T int

type Buffer struct {
	data   []T
	size   int
	start  int
	filled int
}

func New(size int) *Buffer {
	return &Buffer{
		data: make([]T, size),
		size: size,
	}
}

func (b *Buffer) Add(v T) {
	end := (b.start + b.filled) % b.size
	b.data[end] = v
	if b.filled < b.size {
		b.filled++
	} else {
		b.start = (b.start + 1) % b.size
	}
}

func (b *Buffer) Len() int { return b.filled }

func (b *Buffer) At(i int) T {
	return b.data[(b.start+i)%b.size]
}