func NewMon() *ImpMon {
//
var m mon.Monitor
var nR, nW int
f := func(a Any, k uint) Any {
switch k {
case rIn:
for nW > 0 {
m.Wait(rIn)
}
nR++
m.Signal(rIn)
case rOut:
nR--
if nR == 0 {
m.Signal(wIn)
}
case wIn:
for nR > 0 || nW > 0 {
m.Wait(wIn)
}
nW = 1
case wOut:
nW = 0
if m.Awaited(rIn) {
m.Signal(rIn)
} else {
m.Signal(wIn)
}
}
return nil
}
m = mon.New(4, f)
return &ImpMon{m}
}
