blob: 203334edee7a169ec2face928ee0fb5b0644a56c [file] [log] [blame]
package disruptor
import "math"
type SharedWriterBarrier struct {
committed []int32
capacity int64
mask int64
shift uint8
reservation *Cursor
}
func NewSharedWriterBarrier(reservation *Cursor, capacity int64) *SharedWriterBarrier {
assertPowerOfTwo(capacity)
return &SharedWriterBarrier{
committed: prepareCommitBuffer(capacity),
capacity: capacity,
mask: capacity - 1,
shift: uint8(math.Log2(float64(capacity))),
reservation: reservation,
}
}
func prepareCommitBuffer(capacity int64) []int32 {
buffer := make([]int32, capacity)
for i := range buffer {
buffer[i] = int32(InitialSequenceValue)
}
return buffer
}
func (this *SharedWriterBarrier) LoadBarrier(lower int64) int64 {
shift, mask := this.shift, this.mask
upper := this.reservation.Load()
for ; lower <= upper; lower++ {
if this.committed[lower&mask] != int32(lower>>shift) {
return lower - 1
}
}
return upper
}