<?php
/**
 * File caching functions
 *
 * @package Core
 * @author  Andreas Goetz   <hide@address.com>
 * @version $Id: cache.php,v 1.2 2007/12/03 20:04:40 andig2 Exp $
 */

// define cache folder
if (!defined('CACHE')) define('CACHE', 'cache');

function cache_get_filename($url, $cache_folder, $ext = '')
{
    global $config;

    if ($cache_folder) $cache_folder = "$cache_folder/";
    if ($ext) $ext = ".$ext";

    // construct cache file name
    $md5        = md5($url);
    $subdir     = ($config['hierarchical']) ? substr($md5, 0, 1).'/' : '';
    $cache_file = CACHE.'/'.$cache_folder.$subdir.$md5.$ext;

    return $cache_file;
}

/**
 * Verify existance of cached file for given url/ extension
 *
 * @author Andreas Goetz <hide@address.com>
 * @param  string   url of the image
 * @param  string   ext file extension of the image
 * @param  string   file result: URL to the cached image if exists
 * @return bool     result of check
 */
function cache_file_exists($url, &$cache_file, $cache_folder, $ext = '')
{
    $cache_file = cache_get_filename($url, $cache_folder, $ext);
    $result     = file_exists($cache_file) && filesize($cache_file);
    
    return($result);
}

function cache_get($url, $cache_folder, $cache_max_age, $serialize = false)
{
    $data = false;
    
    if ($cache_max_age > 0)
    {
        if (cache_file_exists($url, $cache_file, $cache_folder) &&
           (time()-filemtime($cache_file) < $cache_max_age))
        {
            $data = file_get_contents($cache_file);
            if (($data !== false) && $serialize) $data = unserialize($data);
        }
    }
    
    return $data;
}

function cache_put($url, $data, $cache_folder, $cache_max_age, $serialize = false)
{
    // only put file to cache if caching is enabled
    if ($cache_max_age > 0)
    {
        // get the cache file name
        $cache_file = cache_get_filename($url, $cache_folder);

        // commit to disk
        if ($serialize) $data = serialize($data);
        file_put_contents($cache_file, $data);
    }
}

?>