merge2channels.go

func Merge2Channels(fn func(int) int, in1 <-chan int, in2 <-chan int, out chan<- int, m int) {
	var wg sync.WaitGroup
	wg.Add(1)
	res := make([]int, m*2)
	n := 0
	go func() {
		defer wg.Done()
		for i := 0; i < m; i++ {
			v1 := <-in1
			v2 := <-in2
			wg.Add(1)
			go func(pos int) {
				defer wg.Done()
				v := fn(v1)
				res[pos] = v
			}(n)
			wg.Add(1)
			go func(pos int) {
				defer wg.Done()
				v := fn(v2)
				res[pos+1] = v
			}(n)
			n += 2
		}
	}()
	go func() {
		wg.Wait()
		for i := 0; i < len(res); i += 2 {
			out <- res[i] + res[i+1]
		}
	}()
}