PHP实例：round robin权重轮循算法php实现代码

PHP学习
<?php
/* 
 * Copyright (C) FatHong
 */
/* 数据初始化,weight: 权重 */
$hosts['a'] = array('weight' => 5, 'current_weight' => 0, 'count' => 0);
$hosts['b'] = array('weight' => 3, 'current_weight' => 0, 'count' => 0);
$hosts['c'] = array('weight' => 2, 'current_weight' => 0, 'count' => 0);
$result = array();
/* 模拟10次 */
for ($i = 0; $i < 10; $i++) {
  round_robin($hosts, $result);
}
/* 输出结果 */
print_r($result);
/* round robin 轮循 */
function round_robin(&$hosts, &$result)
{
  $total = 0;
  $best = null;
  foreach ($hosts as $key => $item) {
    $current = &$hosts[$key];
    $weight = $current['weight'];
    $current['current_weight'] += $weight;
    $total += $weight;
    if ( ($best == null) || ($hosts[$best]['current_weight'] < 
                $current['current_weight']) ) 
    {
      $best = $key;
    }
  }
  $hosts[$best]['current_weight'] -= $total;
  $hosts[$best]['count']++;
  $result[] = $best;
}