1<?php
2 /*
3     pCache - Faster renderding using data cache
4     Copyright (C) 2008 Jean-Damien POGOLOTTI
5     Version  1.1.2 last updated on 06/17/08
6
7     http://pchart.sourceforge.net
8
9     This program is free software: you can redistribute it and/or modify
10     it under the terms of the GNU General Public License as published by
11     the Free Software Foundation, either version 1,2,3 of the License, or
12     (at your option) any later version.
13
14     This program is distributed in the hope that it will be useful,
15     but WITHOUT ANY WARRANTY; without even the implied warranty of
16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17     GNU General Public License for more details.
18
19     You should have received a copy of the GNU General Public License
20     along with this program.  If not, see <http://www.gnu.org/licenses/>.
21
22     Class initialisation :
23      pCache($CacheFolder="Cache/")
24     Cache management :
25      IsInCache($Data)
26      GetFromCache($ID,$Data)
27      WriteToCache($ID,$Data,$Picture)
28      DeleteFromCache($ID,$Data)
29      ClearCache()
30     Inner functions :
31      GetHash($ID,$Data)
32 */
33
34 /* pCache class definition */
35 class pCache
36  {
37   var $HashKey     = "";
38   var $CacheFolder = "cache/";
39
40   /* Create the pCache object */
41   function pCache($CacheFolder="cache/")
42    {
43     $this->CacheFolder = $CacheFolder;
44    }
45
46   /* This function is clearing the cache folder */
47   function ClearCache()
48    {
49     if ($handle = opendir($this->CacheFolder))
50      {
51       while (false !== ($file = readdir($handle)))
52        {
53         if ( $file != "." && $file != ".." )
54          unlink($this->CacheFolder.$file);
55        }
56       closedir($handle);
57      }
58    }
59
60   /* This function is checking if we have an offline version of this chart */
61   function IsInCache($ID,$Data,$Hash="")
62    {
63     if ( $Hash == "" )
64      $Hash = $this->GetHash($ID,$Data);
65
66     if ( file_exists($this->CacheFolder.$Hash) )
67      return(TRUE);
68     else
69      return(FALSE);
70    }
71
72   /* This function is making a copy of drawn chart in the cache folder */
73   function WriteToCache($ID,$Data,$Picture)
74    {
75     $Hash     = $this->GetHash($ID,$Data);
76     $FileName = $this->CacheFolder.$Hash;
77
78     imagepng($Picture->Picture,$FileName);
79    }
80
81   /* This function is removing any cached copy of this chart */
82   function DeleteFromCache($ID,$Data)
83    {
84     $Hash     = $this->GetHash($ID,$Data);
85     $FileName = $this->CacheFolder.$Hash;
86
87     if ( file_exists($FileName ) )
88      unlink($FileName);
89    }
90
91   /* This function is retrieving the cached picture if applicable */
92   function GetFromCache($ID,$Data)
93    {
94     $Hash     = $this->GetHash($ID,$Data);
95     if ( $this->IsInCache("","",$Hash ) )
96      {
97       $FileName = $this->CacheFolder.$Hash;
98
99       header('Content-type: image/png');
100       @readfile($FileName);
101       exit();
102      }
103    }
104
105   /* This function is building the graph unique hash key */
106   function GetHash($ID,$Data)
107    {
108     $mKey = "$ID";
109     foreach($Data as $key => $Values)
110      {
111       $tKey = "";
112       foreach($Values as $Serie => $Value)
113        $tKey = $tKey.$Serie.$Value;
114       $mKey = $mKey.md5($tKey);
115      }
116     return(md5($mKey));
117    }
118  }
119?>