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      1 // run
      2 
      3 // Copyright 2009 The Go Authors. All rights reserved.
      4 // Use of this source code is governed by a BSD-style
      5 // license that can be found in the LICENSE file.
      6 
      7 // Test simple select.
      8 
      9 package main
     10 
     11 var counter uint
     12 var shift uint
     13 
     14 func GetValue() uint {
     15 	counter++
     16 	return 1 << shift
     17 }
     18 
     19 func Send(a, b chan uint) int {
     20 	var i int
     21 
     22 LOOP:
     23 	for {
     24 		select {
     25 		case a <- GetValue():
     26 			i++
     27 			a = nil
     28 		case b <- GetValue():
     29 			i++
     30 			b = nil
     31 		default:
     32 			break LOOP
     33 		}
     34 		shift++
     35 	}
     36 	return i
     37 }
     38 
     39 func main() {
     40 	a := make(chan uint, 1)
     41 	b := make(chan uint, 1)
     42 	if v := Send(a, b); v != 2 {
     43 		println("Send returned", v, "!= 2")
     44 		panic("fail")
     45 	}
     46 	if av, bv := <-a, <-b; av|bv != 3 {
     47 		println("bad values", av, bv)
     48 		panic("fail")
     49 	}
     50 	if v := Send(a, nil); v != 1 {
     51 		println("Send returned", v, "!= 1")
     52 		panic("fail")
     53 	}
     54 	if counter != 10 {
     55 		println("counter is", counter, "!= 10")
     56 		panic("fail")
     57 	}
     58 }
     59