使用php快速的进行文件二分查找源码.zip

<?php /** * 设计思路： * 把文件重新格式化，进行二分查找 * 调取方法： * $m = new FileSearch("test.log", 200); * echo $m->search(95500736); //在文件中搜索 * 说明：第一次使用会很慢，因为要生成缓存文件 */ class FileSearch { private $filename; //源文件名 private $maxLength; //源文件中单行的最大长度(按字节算) private $sorted; //源文件是否已经排好序 private $formatFile; //重新格式化存储的文件名 private $fd; /** * 初始化 * @param string $filename 需要检索的文件 * @param int $maxLength 单行的最大长度 * @param int $sorted 源文件是否已经排好序 * @param int $forceReForm 是否强制重新生成索引文件 * @return [type] [description] */ public function __construct($filename, $maxLength, $sorted = 1, $forceReForm = 0) { $this->filename = $filename; $this->maxLength = $maxLength; $this->sorted = $sorted; $this->formatFile = dirname($this->filename)."/filecache/".md5($this->filename); if ($forceReForm || !file_exists($this->formatFile)) { $this->formatFile(); } } /** * 格式化文件 * @return [type] [description] */ private function formatFile() { if ($this->sorted == 0) { //对源文件排序 } //读源文件，写入到新的索引文件 $readfd = fopen($this->filename, 'rb'); $writefd = fopen($this->formatFile.'_tmp', 'wb+'); if ($readfd === false || $writefd === false) { return false; } echo "\n start reformat file $this->filename .."; while (!feof($readfd)) { $line = fgets($readfd, 8192); $id = explode("\t", $line)['0']; fseek($writefd, ($id - 1) * $this->maxLength); fwrite($writefd, pack("a".$this->maxLength, $line)); } echo "\n reformat ok\n"; fclose($readfd); fclose($writefd); rename($this->formatFile.'_tmp', $this->formatFile); } /** * 在索引文件中进行二分查找 * @param int $id 进行二分查找的id * @return [type] [description] */ public function search($key) { $filesize = filesize($this->formatFile); $fd = fopen($this->formatFile, "rb"); $left = 0; //行号 $right = ($filesize / $this->maxLength) - 1; //行号 while ($left <= $right) { $middle = intval(($right + $left)/2); fseek($fd, ($middle) * $this->maxLength); $info = unpack("a*", fread($fd, $this->maxLength))['1']; $lineinfo = explode("\t", $info, 2); if ($lineinfo['0'] > $key) { $right = $middle - 1; } elseif ($lineinfo['0'] < $key) { $left = $middle + 1; } else { fclose($fd); return $lineinfo['1']; } } fclose($fd); return false; } /** * 读取固定行数的文本 * @param int $id 行数 * @return [type] [description] */ public function getLine($key) { $ret = array(); $fd = fopen($this->formatFile, "rb"); if(!is_array($key)) { $key = array($key); } foreach ($key as $v) { if($v < 100) { continue; } fseek($fd, ($v - 1) * $this->maxLength); $info = unpack("a*", fread($fd, $this->maxLength))['1']; $ret[$v] = trim(strstr($info, "\t")); } fclose($fd); return $ret; } }