lib/form/float.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 /**
  19  * Float type form element
  20  *
  21  * Contains HTML class for a float type element
  22  *
  23  * @package   core_form
  24  * @category  form
  25  * @copyright 2019 Shamim Rezaie <shamim@moodle.com>
  26  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 defined('MOODLE_INTERNAL') || die();
  30
  31 global $CFG;
  32 require_once($CFG->libdir . '/form/text.php');
  33
  34 /**
  35  * Float type form element.
  36  *
  37  * This is preferred over the text element when working with float numbers, and takes care of the fact that different languages
  38  * may use different symbols as the decimal separator.
  39  * Using this element, submitted float numbers will be automatically translated from the localised format into the computer format,
  40  * and vice versa when they are being displayed.
  41  *
  42  * @copyright 2019 Shamim Rezaie <shamim@moodle.com>
  43  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  44  */
  45 class MoodleQuickForm_float extends MoodleQuickForm_text {
  46
  47     /**
  48      * MoodleQuickForm_float constructor.
  49      *
  50      * @param string $elementName (optional) name of the float field
  51      * @param string $elementLabel (optional) float field label
  52      * @param string $attributes (optional) Either a typical HTML attribute string or an associative array
  53      */
  54     public function __construct($elementName = null, $elementLabel = null, $attributes = null) {
  55         parent::__construct($elementName, $elementLabel, $attributes);
  56         $this->_type = 'float';
  57     }
  58
  59     /**
  60      * Called by HTML_QuickForm whenever form event is made on this element.
  61      *
  62      * @param string $event Name of event
  63      * @param mixed $arg event arguments
  64      * @param object $caller calling object
  65      * @return bool
  66      */
  67     public function onQuickFormEvent($event, $arg, &$caller) {
  68         switch ($event) {
  69             case 'updateValue':
  70                 if ($value = $this->_findValue($caller->_constantValues)) {
  71                     $value = $this->format_float($value);
  72                 }
  73                 if (null === $value) {
  74                     $value = $this->_findValue($caller->_submitValues);
  75                     if (null === $value) {
  76                         if ($value = $this->_findValue($caller->_defaultValues)) {
  77                             $value = $this->format_float($value);
  78                         }
  79                     }
  80                 }
  81                 if (null !== $value) {
  82                     parent::setValue($value);
  83                 }
  84                 return true;
  85             case 'createElement':
  86                 $caller->setType($arg[0], PARAM_RAW_TRIMMED);
  87             default:
  88                 return parent::onQuickFormEvent($event, $arg, $caller);
  89         }
  90     }
  91
  92     /**
  93      * Checks that the submitted value is a valid float number.
  94      *
  95      * @param string $value The localised float number that is submitted.
  96      * @return string|null Validation error message or null.
  97      */
  98     public function validateSubmitValue($value) {
  99         if (false === unformat_float($value, true)) {
 100             return get_string('err_numeric', 'core_form');
 101         }
 102     }
 103
 104     /**
 105      * Sets the value of the form element.
 106      *
 107      * @param string $value Default value of the form element
 108      */
 109     public function setValue($value) {
 110         $value = $this->format_float($value);
 111         parent::setValue($value);
 112     }
 113
 114     /**
 115      * Returns the value of the form element.
 116      *
 117      * @return false|float
 118      */
 119     public function getValue() {
 120         $value = parent::getValue();
 121         if ($value) {
 122             $value = unformat_float($value, true);
 123         }
 124         return $value;
 125     }
 126
 127     /**
 128      * Returns a 'safe' element's value.
 129      *
 130      * @param  array   $submitValues array of submitted values to search
 131      * @param  bool    $assoc whether to return the value as associative array
 132      * @return mixed
 133      */
 134     public function exportValue(&$submitValues, $assoc = false) {
 135         $value = $this->_findValue($submitValues);
 136         if (null === $value) {
 137             $value = $this->getValue();
 138         } else if ($value) {
 139             $value = unformat_float($value, true);
 140         }
 141         return $this->_prepareValue($value, $assoc);
 142     }
 143
 144     /**
 145      * Used by getFrozenHtml() to pass the element's value if _persistantFreeze is on.
 146      *
 147      * @return string
 148      */
 149     public function _getPersistantData() {
 150         if (!$this->_persistantFreeze) {
 151             return '';
 152         } else {
 153             $id = $this->getAttribute('id');
 154             if (isset($id)) {
 155                 // Id of persistant input is different then the actual input.
 156                 $id = array('id' => $id . '_persistant');
 157             } else {
 158                 $id = array();
 159             }
 160
 161             return '<input' . $this->_getAttrString(array(
 162                         'type'  => 'hidden',
 163                         'name'  => $this->getAttribute('name'),
 164                         'value' => $this->getAttribute('value')
 165                     ) + $id) . ' />';
 166         }
 167     }
 168
 169     /**
 170      * Given a float, prints it nicely.
 171      * This function reserves the number of decimal places.
 172      *
 173      * @param float|null $value The float number to format
 174      * @return string Localised float
 175      */
 176     private function format_float($value) {
 177         if (is_numeric($value)) {
 178             // We want to keep trailing zeros after the decimal point if there is any.
 179             // Therefore we cannot just call format_float() and pass -1 as the number of decimal points.
 180             $pieces = preg_split('/E/i', $value); // In case it is in the scientific format.
 181             $decimalpos = strpos($pieces[0], '.');
 182             if ($decimalpos !== false) {
 183                 $decimalpart = substr($pieces[0], $decimalpos + 1);
 184                 $decimals = strlen($decimalpart);
 185             } else {
 186                 $decimals = 0;
 187             }
 188             $pieces[0] = format_float($pieces[0], $decimals);
 189             $value = implode('E', $pieces);
 190         }
 191         return $value;
 192     }
 193 }