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47 lines
759 B
Go

package stbl
type intRing struct {
items []int
next int // index of the next available slot
full bool // whether or not we've filled the ring
base int // index in items of the virtual zero index
}
func newIntRing(size int) *intRing {
return &intRing{
items: make([]int, size),
}
}
func (r *intRing) add(i int) {
r.items[r.next] = i
r.next = r.incr(r.next)
if !r.full && r.next == 0 {
r.full = true
}
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if r.full {
r.base = r.incr(r.base)
}
}
func (r *intRing) incr(i int) int {
if i == len(r.items)-1 {
return 0
}
return i + 1
}
func (r *intRing) at(i int) int {
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idx := r.base + i
for idx >= len(r.items) {
idx -= len(r.items)
}
return r.items[idx]
}
func (r *intRing) clear() {
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r.next = 0
r.full = false
r.base = 0
}