Imported Upstream version 60upstream/60

1 files changed, 57 insertions, 0 deletions

diff --git a/test/chan/fifo.go b/test/chan/fifo.go
new file mode 100644
index 000000000..0dddfcaa0
--- /dev/null
+++ b/test/chan/fifo.go
@@ -0,0 +1,57 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Verify that unbuffered channels act as pure fifos.
+
+package main
+
+import "os"
+
+const N = 10
+
+func AsynchFifo() {
+	ch := make(chan int, N)
+	for i := 0; i < N; i++ {
+		ch <- i
+	}
+	for i := 0; i < N; i++ {
+		if <-ch != i {
+			print("bad receive\n")
+			os.Exit(1)
+		}
+	}
+}
+
+func Chain(ch <-chan int, val int, in <-chan int, out chan<- int) {
+	<-in
+	if <-ch != val {
+		panic(val)
+	}
+	out <- 1
+}
+
+// thread together a daisy chain to read the elements in sequence
+func SynchFifo() {
+	ch := make(chan int)
+	in := make(chan int)
+	start := in
+	for i := 0; i < N; i++ {
+		out := make(chan int)
+		go Chain(ch, i, in, out)
+		in = out
+	}
+	start <- 0
+	for i := 0; i < N; i++ {
+		ch <- i
+	}
+	<-in
+}
+
+func main() {
+	AsynchFifo()
+	SynchFifo()
+}
+