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64 lines
1019 B
Go
64 lines
1019 B
Go
package collection
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import (
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"sync"
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)
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// A Ring can be used as fixed size ring.
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type Ring struct {
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elements []any
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index int
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lock sync.RWMutex
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}
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// NewRing returns a Ring object with the given size n.
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func NewRing(n int) *Ring {
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if n < 1 {
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panic("n should be greater than 0")
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}
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return &Ring{
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elements: make([]any, n),
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}
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}
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// Add adds v into r.
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func (r *Ring) Add(v any) {
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r.lock.Lock()
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defer r.lock.Unlock()
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ringLength := len(r.elements)
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r.elements[r.index%ringLength] = v
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r.index++
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// prevent ring index overflow
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if r.index/ringLength >= 2 {
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r.index = r.index - ringLength
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}
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}
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// Take takes all items from r.
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func (r *Ring) Take() []any {
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r.lock.RLock()
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defer r.lock.RUnlock()
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var size int
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var start int
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ringLength := len(r.elements)
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if r.index > ringLength {
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size = ringLength
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start = r.index % ringLength
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} else {
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size = r.index
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}
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elements := make([]any, size)
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for i := 0; i < size; i++ {
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elements[i] = r.elements[(start+i)%ringLength]
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}
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return elements
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}
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