classes/plfiltercondition.php

   1 <?php
   2 /***************************************************************************
   3  *  Copyright (C) 2003-2010 Polytechnique.org                              *
   4  *  http://opensource.polytechnique.org/                                   *
   5  *                                                                         *
   6  *  This program is free software; you can redistribute it and/or modify   *
   7  *  it under the terms of the GNU General Public License as published by   *
   8  *  the Free Software Foundation; either version 2 of the License, or      *
   9  *  (at your option) any later version.                                    *
  10  *                                                                         *
  11  *  This program is distributed in the hope that it will be useful,        *
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
  14  *  GNU General Public License for more details.                           *
  15  *                                                                         *
  16  *  You should have received a copy of the GNU General Public License      *
  17  *  along with this program; if not, write to the Free Software            *
  18  *  Foundation, Inc.,                                                      *
  19  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA                *
  20  ***************************************************************************/
  21
  22 // {{{ interface PlFilterCondition
  23 interface PlFilterCondition
  24 {
  25     const COND_TRUE  = 'TRUE';
  26     const COND_FALSE = 'FALSE';
  27
  28     public function buildCondition(PlFilter &$pf);
  29 }
  30 // }}}
  31
  32 // {{{ class PFC_OneChild
  33 abstract class PFC_OneChild implements PlFilterCondition
  34 {
  35     protected $child;
  36
  37     public function __construct($child = null)
  38     {
  39         if (!is_null($child) && ($child instanceof PlFilterCondition)) {
  40             $this->setChild($child);
  41         }
  42     }
  43
  44     public function setChild(PlFilterCondition &$cond)
  45     {
  46         $this->child =& $cond;
  47     }
  48 }
  49 // }}}
  50
  51 // {{{ class PFC_NChildren
  52 abstract class PFC_NChildren implements PlFilterCondition
  53 {
  54     protected $children = array();
  55
  56     public function __construct()
  57     {
  58         $children = func_get_args();
  59         foreach ($children as &$child) {
  60             if (!is_null($child) && ($child instanceof PlFilterCondition)) {
  61                 $this->addChild($child);
  62             }
  63         }
  64     }
  65
  66     public function addChild(PlFilterCondition &$cond)
  67     {
  68         $this->children[] =& $cond;
  69     }
  70
  71     protected function catConds(array $cond, $op, $fallback)
  72     {
  73         if (count($cond) == 0) {
  74             return $fallback;
  75         } else if (count($cond) == 1) {
  76             return $cond[0];
  77         } else {
  78             return '(' . implode(') ' . $op . ' (', $cond) . ')';
  79         }
  80     }
  81 }
  82 // }}}
  83
  84 // {{{ class PFC_True
  85 class PFC_True implements PlFilterCondition
  86 {
  87     public function buildCondition(PlFilter &$uf)
  88     {
  89         return self::COND_TRUE;
  90     }
  91 }
  92 // }}}
  93
  94 // {{{ class PFC_False
  95 class PFC_False implements PlFilterCondition
  96 {
  97     public function buildCondition(PlFilter &$uf)
  98     {
  99         return self::COND_FALSE;
 100     }
 101 }
 102 // }}}
 103
 104 // {{{ class PFC_Not
 105 class PFC_Not extends PFC_OneChild
 106 {
 107     public function buildCondition(PlFilter &$uf)
 108     {
 109         $val = $this->child->buildCondition($uf);
 110         if ($val == self::COND_TRUE) {
 111             return self::COND_FALSE;
 112         } else if ($val == self::COND_FALSE) {
 113             return self::COND_TRUE;
 114         } else {
 115             return 'NOT (' . $val . ')';
 116         }
 117     }
 118 }
 119 // }}}
 120
 121 // {{{ class PFC_And
 122 class PFC_And extends PFC_NChildren
 123 {
 124     public function buildCondition(PlFilter &$uf)
 125     {
 126         if (empty($this->children)) {
 127             return self::COND_FALSE;
 128         } else {
 129             $true = self::COND_FALSE;
 130             $conds = array();
 131             foreach ($this->children as &$child) {
 132                 $val = $child->buildCondition($uf);
 133                 if ($val == self::COND_TRUE) {
 134                     $true = self::COND_TRUE;
 135                 } else if ($val == self::COND_FALSE) {
 136                     return self::COND_FALSE;
 137                 } else {
 138                     $conds[] = $val;
 139                 }
 140             }
 141             return $this->catConds($conds, 'AND', $true);
 142         }
 143     }
 144 }
 145 // }}}
 146
 147 // {{{ class PFC_Or
 148 class PFC_Or extends PFC_NChildren
 149 {
 150     public function buildCondition(PlFilter &$uf)
 151     {
 152         if (empty($this->children)) {
 153             return self::COND_TRUE;
 154         } else {
 155             $true = self::COND_TRUE;
 156             $conds = array();
 157             foreach ($this->children as &$child) {
 158                 $val = $child->buildCondition($uf);
 159                 if ($val == self::COND_TRUE) {
 160                     return self::COND_TRUE;
 161                 } else if ($val == self::COND_FALSE) {
 162                     $true = self::COND_FALSE;
 163                 } else {
 164                     $conds[] = $val;
 165                 }
 166             }
 167             return $this->catConds($conds, 'OR', $true);
 168         }
 169     }
 170 }
 171 // }}}
 172 ?>