From 6e3be7f3d5a1897c781dd569f534526b8c2b8c6f Mon Sep 17 00:00:00 2001 From: Yong Tang Date: Fri, 28 Apr 2017 09:14:54 -0700 Subject: Update vendor with `go dep` This fix updates vendor with `go dep` Signed-off-by: Yong Tang --- vendor/github.com/eapache/queue/queue.go | 88 ++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 vendor/github.com/eapache/queue/queue.go (limited to 'vendor/github.com/eapache/queue/queue.go') diff --git a/vendor/github.com/eapache/queue/queue.go b/vendor/github.com/eapache/queue/queue.go new file mode 100644 index 000000000..2dc8d9395 --- /dev/null +++ b/vendor/github.com/eapache/queue/queue.go @@ -0,0 +1,88 @@ +/* +Package queue provides a fast, ring-buffer queue based on the version suggested by Dariusz Górecki. +Using this instead of other, simpler, queue implementations (slice+append or linked list) provides +substantial memory and time benefits, and fewer GC pauses. + +The queue implemented here is as fast as it is for an additional reason: it is *not* thread-safe. +*/ +package queue + +const minQueueLen = 16 + +// Queue represents a single instance of the queue data structure. +type Queue struct { + buf []interface{} + head, tail, count int +} + +// New constructs and returns a new Queue. +func New() *Queue { + return &Queue{ + buf: make([]interface{}, minQueueLen), + } +} + +// Length returns the number of elements currently stored in the queue. +func (q *Queue) Length() int { + return q.count +} + +// resizes the queue to fit exactly twice its current contents +// this can result in shrinking if the queue is less than half-full +func (q *Queue) resize() { + newBuf := make([]interface{}, q.count*2) + + if q.tail > q.head { + copy(newBuf, q.buf[q.head:q.tail]) + } else { + n := copy(newBuf, q.buf[q.head:]) + copy(newBuf[n:], q.buf[:q.tail]) + } + + q.head = 0 + q.tail = q.count + q.buf = newBuf +} + +// Add puts an element on the end of the queue. +func (q *Queue) Add(elem interface{}) { + if q.count == len(q.buf) { + q.resize() + } + + q.buf[q.tail] = elem + q.tail = (q.tail + 1) % len(q.buf) + q.count++ +} + +// Peek returns the element at the head of the queue. This call panics +// if the queue is empty. +func (q *Queue) Peek() interface{} { + if q.count <= 0 { + panic("queue: Peek() called on empty queue") + } + return q.buf[q.head] +} + +// Get returns the element at index i in the queue. If the index is +// invalid, the call will panic. +func (q *Queue) Get(i int) interface{} { + if i < 0 || i >= q.count { + panic("queue: Get() called with index out of range") + } + return q.buf[(q.head+i)%len(q.buf)] +} + +// Remove removes the element from the front of the queue. If you actually +// want the element, call Peek first. This call panics if the queue is empty. +func (q *Queue) Remove() { + if q.count <= 0 { + panic("queue: Remove() called on empty queue") + } + q.buf[q.head] = nil + q.head = (q.head + 1) % len(q.buf) + q.count-- + if len(q.buf) > minQueueLen && q.count*4 == len(q.buf) { + q.resize() + } +} -- cgit v1.2.3