Drupal 6 time field element

Drupal core offers a standard date field type, but it has no knowledge of a field type to represent (a certain moment in) time. The following snippet of code generates a Drupal 6 time element for you which you can use in all your forms. It consists of 3 select fields representing hour, minute and meridiem (like 12:01 PM).

An example of usage is the following:

$form['test_reset']['test_reset_time'] = array(
    '#type' => 'test_time',
    '#title' => t('Reset time'),
    '#default_value' => variable_get('test_reset_time', array('hour' => 12, 'minute' => 0, 'meridiem' => 'pm')),
);

The code for the element is:

<?php
function time_field_elements() {
  $type['time_field_time'] = array(
    '#input' => TRUE,
    '#process' => array('time_field_expand_time'),
  );
  return $type;
}

function time_field_expand_time($element) {
  if (empty($element['#value'])) {
    $element['#value'] = array(
      'hour' => intval(format_date(time(), 'custom', 'h')),
      'minute' => intval(format_date(time(), 'custom', 'i')),
      'meridiem' => format_date(time(), 'custom', 'a'),
    );
  }
  
  $element['#tree'] = TRUE;

  foreach ($element['#value'] as $type => $value) {
    switch ($type) {
      case 'hour':
        $options = drupal_map_assoc(range(1, 12));
        break;
      case 'minute':
        $options = drupal_map_assoc(range(0, 59));
        break;
      case 'meridiem':
        $options = drupal_map_assoc(array('am', 'pm'));
        break;
    }
    
    if ($type == 'hour' || $type == 'minute') {
      foreach ($options as $option) {
        $options[$option] = str_pad($options[$option], 2, '0', STR_PAD_LEFT);
      }
    }
    $parents = $element['#parents'];
    $parents[] = $type;
    $element[$type] = array(
      '#type' => 'select',
      '#default_value' => $element['#value'][$type],
      '#attributes' => $element['#attributes'],
      '#options' => $options,
    );
  }

  return $element;
}

/**
 * Implementation of hook_theme().
 */
function time_field_theme($existing, $type, $theme, $path) {
  return array(
    'time_field_time' => array(
      'arguments' => array('element' => NULL),
    ),
  );
}

function theme_time_field_time($element) {
  return theme('form_element', $element, '<div class="container-inline">'. $element['#children'] .'</div>');
}