import "container/ring"
Package ring implements operations on circular lists.
type Ring struct {
Value interface{} // for use by client; untouched by this library
// contains filtered or unexported fields
}
A Ring is an element of a circular list, or ring. Rings do not have a beginning or end; a pointer to any ring element serves as reference to the entire ring. Empty rings are represented as nil Ring pointers. The zero value for a Ring is a one-element ring with a nil Value.
func New(n int) *Ring
New creates a ring of n elements.
func (r *Ring) Do(f func(interface{}))
Do calls function f on each element of the ring, in forward order. The behavior of Do is undefined if f changes *r.
Code:
// Create a new ring of size 5 r := ring.New(5) // Get the length of the ring n := r.Len() // Initialize the ring with some integer values for i := 0; i < n; 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 (r *Ring) Len() int
Len computes the number of elements in ring r. It executes in time proportional to the number of elements.
Code:
// Create a new ring of size 4 r := ring.New(4) // Print out its length fmt.Println(r.Len())
Output:
4
func (r *Ring) Link(s *Ring) *Ring
Link connects ring r with ring s such that r.Next() becomes s and returns the original value for r.Next(). r must not be empty.
If r and s point to the same ring, linking them removes the elements between r and s from the ring. The removed elements form a subring and the result is a reference to that subring (if no elements were removed, the result is still the original value for r.Next(), and not nil).
If r and s point to different rings, linking them creates a single ring with the elements of s inserted after r. The result points to the element following the last element of s after insertion.
Code:
// Create two rings, r and s, of size 2 r := ring.New(2) s := ring.New(2) // Get the length of the ring lr := r.Len() ls := s.Len() // Initialize r with 0s for i := 0; i < lr; i++ { r.Value = 0 r = r.Next() } // Initialize s with 1s for j := 0; j < ls; 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 (r *Ring) Move(n int) *Ring
Move moves n % r.Len() elements backward (n < 0) or forward (n >= 0) in the ring and returns that ring element. r must not be empty.
Code:
// Create a new ring of size 5 r := ring.New(5) // Get the length of the ring n := r.Len() // Initialize the ring with some integer values for i := 0; i < n; 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 (r *Ring) Next() *Ring
Next returns the next ring element. r must not be empty.
Code:
// Create a new ring of size 5 r := ring.New(5) // Get the length of the ring n := r.Len() // Initialize the ring with some integer values for i := 0; i < n; i++ { r.Value = i r = r.Next() } // Iterate through the ring and print its contents for j := 0; j < n; j++ { fmt.Println(r.Value) r = r.Next() }
Output:
0 1 2 3 4
func (r *Ring) Prev() *Ring
Prev returns the previous ring element. r must not be empty.
Code:
// Create a new ring of size 5 r := ring.New(5) // Get the length of the ring n := r.Len() // Initialize the ring with some integer values for i := 0; i < n; i++ { r.Value = i r = r.Next() } // Iterate through the ring backwards and print its contents for j := 0; j < n; j++ { r = r.Prev() fmt.Println(r.Value) }
Output:
4 3 2 1 0
func (r *Ring) Unlink(n int) *Ring
Unlink removes n % r.Len() elements from the ring r, starting at r.Next(). If n % r.Len() == 0, r remains unchanged. The result is the removed subring. r must not be empty.
Code:
// Create a new ring of size 6 r := ring.New(6) // Get the length of the ring n := r.Len() // Initialize the ring with some integer values for i := 0; i < n; 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