diff options
Diffstat (limited to 'src/pkg/container/ring/ring.go')
-rw-r--r-- | src/pkg/container/ring/ring.go | 141 |
1 files changed, 0 insertions, 141 deletions
diff --git a/src/pkg/container/ring/ring.go b/src/pkg/container/ring/ring.go deleted file mode 100644 index 6d3b3e5b3..000000000 --- a/src/pkg/container/ring/ring.go +++ /dev/null @@ -1,141 +0,0 @@ -// 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. - -// Package ring implements operations on circular lists. -package ring - -// 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. -// -type Ring struct { - next, prev *Ring - Value interface{} // for use by client; untouched by this library -} - -func (r *Ring) init() *Ring { - r.next = r - r.prev = r - return r -} - -// Next returns the next ring element. r must not be empty. -func (r *Ring) Next() *Ring { - if r.next == nil { - return r.init() - } - return r.next -} - -// Prev returns the previous ring element. r must not be empty. -func (r *Ring) Prev() *Ring { - if r.next == nil { - return r.init() - } - return r.prev -} - -// 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. -// -func (r *Ring) Move(n int) *Ring { - if r.next == nil { - return r.init() - } - switch { - case n < 0: - for ; n < 0; n++ { - r = r.prev - } - case n > 0: - for ; n > 0; n-- { - r = r.next - } - } - return r -} - -// New creates a ring of n elements. -func New(n int) *Ring { - if n <= 0 { - return nil - } - r := new(Ring) - p := r - for i := 1; i < n; i++ { - p.next = &Ring{prev: p} - p = p.next - } - p.next = r - r.prev = p - return r -} - -// 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. -// -func (r *Ring) Link(s *Ring) *Ring { - n := r.Next() - if s != nil { - p := s.Prev() - // Note: Cannot use multiple assignment because - // evaluation order of LHS is not specified. - r.next = s - s.prev = r - n.prev = p - p.next = n - } - return n -} - -// 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. -// -func (r *Ring) Unlink(n int) *Ring { - if n <= 0 { - return nil - } - return r.Link(r.Move(n + 1)) -} - -// Len computes the number of elements in ring r. -// It executes in time proportional to the number of elements. -// -func (r *Ring) Len() int { - n := 0 - if r != nil { - n = 1 - for p := r.Next(); p != r; p = p.next { - n++ - } - } - return n -} - -// Do calls function f on each element of the ring, in forward order. -// The behavior of Do is undefined if f changes *r. -func (r *Ring) Do(f func(interface{})) { - if r != nil { - f(r.Value) - for p := r.Next(); p != r; p = p.next { - f(p.Value) - } - } -} |