mirror of https://github.com/perkeep/perkeep.git
89 lines
2.7 KiB
Go
89 lines
2.7 KiB
Go
|
// mgo - MongoDB driver for Go
|
||
|
|
//
|
||
|
|
// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net>
|
||
|
|
//
|
||
|
|
// All rights reserved.
|
||
|
|
//
|
||
|
|
// Redistribution and use in source and binary forms, with or without
|
||
|
|
// modification, are permitted provided that the following conditions are met:
|
||
|
|
//
|
||
|
|
// 1. Redistributions of source code must retain the above copyright notice, this
|
||
|
|
// list of conditions and the following disclaimer.
|
||
|
|
// 2. Redistributions in binary form must reproduce the above copyright notice,
|
||
|
|
// this list of conditions and the following disclaimer in the documentation
|
||
|
|
// and/or other materials provided with the distribution.
|
||
|
|
//
|
||
|
|
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
|
||
|
|
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
||
|
|
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||
|
|
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
|
||
|
|
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
||
|
|
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||
|
|
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
||
|
|
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||
|
|
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
||
|
|
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
|
||
|
|
package mgo
|
||
|
|
|
||
|
|
type queue struct {
|
||
|
|
elems []interface{}
|
||
|
|
nelems, popi, pushi int
|
||
|
|
}
|
||
|
|
|
||
|
|
func (q *queue) Len() int {
|
||
|
|
return q.nelems
|
||
|
|
}
|
||
|
|
|
||
|
|
func (q *queue) Push(elem interface{}) {
|
||
|
|
//debugf("Pushing(pushi=%d popi=%d cap=%d): %#v\n",
|
||
|
|
// q.pushi, q.popi, len(q.elems), elem)
|
||
|
|
if q.nelems == len(q.elems) {
|
||
|
|
q.expand()
|
||
|
|
}
|
||
|
|
q.elems[q.pushi] = elem
|
||
|
|
q.nelems++
|
||
|
|
q.pushi = (q.pushi + 1) % len(q.elems)
|
||
|
|
//debugf(" Pushed(pushi=%d popi=%d cap=%d): %#v\n",
|
||
|
|
// q.pushi, q.popi, len(q.elems), elem)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (q *queue) Pop() (elem interface{}) {
|
||
|
|
//debugf("Popping(pushi=%d popi=%d cap=%d)\n",
|
||
|
|
// q.pushi, q.popi, len(q.elems))
|
||
|
|
if q.nelems == 0 {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
elem = q.elems[q.popi]
|
||
|
|
q.elems[q.popi] = nil // Help GC.
|
||
|
|
q.nelems--
|
||
|
|
q.popi = (q.popi + 1) % len(q.elems)
|
||
|
|
//debugf(" Popped(pushi=%d popi=%d cap=%d): %#v\n",
|
||
|
|
// q.pushi, q.popi, len(q.elems), elem)
|
||
|
|
return elem
|
||
|
|
}
|
||
|
|
|
||
|
|
func (q *queue) expand() {
|
||
|
|
curcap := len(q.elems)
|
||
|
|
var newcap int
|
||
|
|
if curcap == 0 {
|
||
|
|
newcap = 8
|
||
|
|
} else if curcap < 1024 {
|
||
|
|
newcap = curcap * 2
|
||
|
|
} else {
|
||
|
|
newcap = curcap + (curcap / 4)
|
||
|
|
}
|
||
|
|
elems := make([]interface{}, newcap)
|
||
|
|
|
||
|
|
if q.popi == 0 {
|
||
|
|
copy(elems, q.elems)
|
||
|
|
q.pushi = curcap
|
||
|
|
} else {
|
||
|
|
newpopi := newcap - (curcap - q.popi)
|
||
|
|
copy(elems, q.elems[:q.popi])
|
||
|
|
copy(elems[newpopi:], q.elems[q.popi:])
|
||
|
|
q.popi = newpopi
|
||
|
|
}
|
||
|
|
q.elems = elems
|
||
|
|
}
|