<?php
/**
 * FileIO Index File System
 *
 * 把遠端圖檔的各種屬性作本機快取及記錄，方便程式取用
 *
 * @package PMCLibrary
 * @version $Id: ifs.php 393 2007-04-30 11:25:29Z scribe $
 * @date $Date: 2007-04-30 19:25:29 +0800 (星期一, 30 四月 2007) $
 */

class IndexFS{
	var $logfile, $backend, $index, $modified;

	/* 建構元 */
	function IndexFS($logfile){
		$this->logfile = $logfile; // 索引記錄檔位置
	}

	/* 初始化 */
	function init(){
		switch($this->backend){
			case 'log':
				touch($this->logfile); chmod($this->logfile, 0666); // 建立索引檔
				break;
			case 'sqlite2':
				$execText = 'CREATE TABLE IndexFS (
				"imgName" VARCHAR(20)  NOT NULL PRIMARY KEY,
				"imgSize" INTEGER  NOT NULL,
				"imgURL" VARCHAR(255)  NOT NULL
				); CREATE INDEX IDX_IndexFS_imgName ON IndexFS(imgName);';
				sqlite_exec($this->index, $execText);
				break;
		}
	}

	/* 開啟索引檔並讀入 */
	function openIndex(){
		if(extension_loaded('SQLite')){
			$this->backend = 'sqlite2';
			$this->index = sqlite_open($this->logfile, 0666);
			if(sqlite_num_rows(sqlite_query($this->index, "SELECT name FROM sqlite_master WHERE name LIKE 'IndexFS'"))===0) $this->init();
		}else{
			$this->backend = 'log';
			$this->modified = false;
			if(!file_exists($this->logfile)){ $this->init(); return; }
			if(filesize($this->logfile)==0) return;
			$indexlog = file($this->logfile); $indexlog_count = count($indexlog); // 讀入索引檔並計算目前筆數
			$this->index = array();
			for($i = 0; $i < $indexlog_count; $i++){
				if(!($trimline = rtrim($indexlog[$i]))) continue; // 本行無意義
				$field = explode("\t\t", $trimline);
				$this->index[$field[0]] = array('imgSize' => $field[1], 'imgURL' => $field[2]);
				// 索引格式: 檔名	檔案大小	對應路徑
			}
			unset($indexlog);
		}
	}

	/* 索引是否存在 */
	function beRecord($id){
		switch($this->backend){
			case 'log':
				return isset($this->index[$id]);
			case 'sqlite2':
				return (sqlite_fetch_array(sqlite_query($this->index, 'SELECT imgName FROM IndexFS WHERE imgName = "'.sqlite_escape_string($id).'"'), SQLITE_ASSOC) ? true : false);
		}
	}

	/* 取得一筆索引 */
	function getRecord($id){
		switch($this->backend){
			case 'log':
				return isset($this->index[$id]) ? $this->index[$id] : false;
			case 'sqlite2':
				return sqlite_fetch_array(sqlite_query($this->index, 'SELECT * FROM IndexFS WHERE imgName = "'.sqlite_escape_string($id).'"'), SQLITE_ASSOC);
		}
	}

	/* 新增一筆索引 */
	function addRecord($id, $imgSize, $imgURL){
		switch($this->backend){
			case 'log':
				$this->modified = true;
				$this->index[$id] = array('imgSize' => $imgSize, 'imgURL' => $imgURL); // 加入索引之中
				break;
			case 'sqlite2':
				sqlite_exec($this->index, 'INSERT INTO IndexFS (imgName, imgSize, imgURL) VALUES ("'.sqlite_escape_string($id).'", '.sqlite_escape_string($imgSize).', "'.sqlite_escape_string($imgURL).'");');
				break;
		}
	}

	/* 刪除一筆索引 */
	function delRecord($id){
		switch($this->backend){
			case 'log':
				if(isset($this->index[$id])){ unset($this->index[$id]); $this->modified = true; return true; }
				return false;
			case 'sqlite2':
				return sqlite_exec($this->index, 'DELETE FROM IndexFS WHERE imgName = "'.sqlite_escape_string($id).'";');
		}
	}

	/* 儲存索引變更 */
	function saveIndex(){
		if($this->backend=='log' && $this->modified){ // 如果有修改索引就回存
			$indexlog = '';
			if(count($this->index)) foreach($this->index as $ikey => $ival){ $indexlog .= $ikey."\t\t".$ival['imgSize']."\t\t".$ival['imgURL']."\n"; } // 有資料才跑迴圈
			$fp = fopen($this->logfile, 'w');
			fwrite($fp, $indexlog);
			fclose($fp);
		}elseif($this->backend=='sqlite2'){
			sqlite_close($this->index);
		}
	}
}
?>