container/ring: add examples for various Ring functions

Change-Id: I6b16cfcbe824f999c9b64df539deea567e327db7
Reviewed-on: https://go-review.googlesource.com/73090
Reviewed-by: Gabriel Aszalos <gabriel.aszalos@gmail.com>
Reviewed-by: Jason Wangsadinata <jwangsadinata@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Gabriel Aszalos <gabriel.aszalos@gmail.com>

diff --git a/src/container/ring/example_test.go b/src/container/ring/example_test.go
new file mode 100644 (file)
index 0000000..ebea1e2
--- /dev/null
+++ b/src/container/ring/example_test.go
@@ -0,0 +1,174 @@
+// Copyright 2017 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.
+
+package ring_test
+
+import (
+       "container/ring"
+       "fmt"
+)
+
+func ExampleRing_Len() {
+       // Create a new ring of size 4
+       r := ring.New(4)
+
+       // Print out its length
+       fmt.Println(r.Len())
+
+       // Output:
+       // 4
+}
+
+func ExampleRing_Next() {
+       // Create a new ring of size 5
+       r := ring.New(5)
+
+       // Initialize the ring with some integer values
+       for i := 0; i < r.Len(); i++ {
+               r.Value = i
+               r = r.Next()
+       }
+
+       // Iterate through the ring and print its contents
+       for j := 0; j < r.Len(); j++ {
+               fmt.Println(r.Value)
+               r = r.Next()
+       }
+
+       // Output:
+       // 0
+       // 1
+       // 2
+       // 3
+       // 4
+}
+
+func ExampleRing_Prev() {
+       // Create a new ring of size 5
+       r := ring.New(5)
+
+       // Initialize the ring with some integer values
+       for i := 0; i < r.Len(); i++ {
+               r.Value = i
+               r = r.Next()
+       }
+
+       // Iterate through the ring backwards and print its contents
+       for j := 0; j < r.Len(); j++ {
+               r = r.Prev()
+               fmt.Println(r.Value)
+       }
+
+       // Output:
+       // 4
+       // 3
+       // 2
+       // 1
+       // 0
+}
+
+func ExampleRing_Do() {
+       // Create a new ring of size 5
+       r := ring.New(5)
+
+       // Initialize the ring with some integer values
+       for i := 0; i < r.Len(); i++ {
+               r.Value = i
+               r = r.Next()
+       }
+
+       // Iterate through the ring and print its contents
+       r.Do(func(p interface{}) {
+               fmt.Println(p.(int))
+       })
+
+       // Output:
+       // 0
+       // 1
+       // 2
+       // 3
+       // 4
+}
+
+func ExampleRing_Move() {
+       // Create a new ring of size 5
+       r := ring.New(5)
+
+       // Initialize the ring with some integer values
+       for i := 0; i < r.Len(); i++ {
+               r.Value = i
+               r = r.Next()
+       }
+
+       // Move the pointer forward by three steps
+       r = r.Move(3)
+
+       // Iterate through the ring and print its contents
+       r.Do(func(p interface{}) {
+               fmt.Println(p.(int))
+       })
+
+       // Output:
+       // 3
+       // 4
+       // 0
+       // 1
+       // 2
+}
+
+func ExampleRing_Link() {
+       // Create two rings, r and s, of size 2
+       r := ring.New(2)
+       s := ring.New(2)
+
+       // Initialize r with 0s
+       for i := 0; i < r.Len(); i++ {
+               r.Value = 0
+               r = r.Next()
+       }
+
+       // Initialize s with 1s
+       for j := 0; j < s.Len(); j++ {
+               s.Value = 1
+               s = s.Next()
+       }
+
+       // Link ring r and ring s
+       rs := r.Link(s)
+
+       // Iterate through the combined ring and print its contents
+       rs.Do(func(p interface{}) {
+               fmt.Println(p.(int))
+       })
+
+       // Output:
+       // 0
+       // 0
+       // 1
+       // 1
+}
+
+func ExampleRing_Unlink() {
+       // Create a new ring of size 6
+       r := ring.New(6)
+
+       // Initialize the ring with some integer values
+       for i := 0; i < r.Len(); i++ {
+               r.Value = i
+               r = r.Next()
+       }
+
+       // Unlink three elements from r, starting from r.Next()
+       r.Unlink(3)
+
+       // Iterate through the remaining ring and print its contents
+       r.Do(func(p interface{}) {
+               fmt.Println(p.(int))
+       })
+
+       // Output:
+       // 0
+       // 4
+       // 5
+}