CForumCacheManager::Compress

static function Compress($arDictCollection)
{
	if (
		is_array($arDictCollection) &&
		(sizeof($arDictCollection) > 9)
	)
	{
		reset($arDictCollection);
		$arFirst = current($arDictCollection);
		$arKeys = array_keys($arFirst);
		$i = 0;

		foreach($arDictCollection as &$arDictionary)
		{
			if ($i++ === 0)
				continue;

			foreach($arKeys as $k)
			{
				if (isset($arDictionary[$k]) && ($arDictionary[$k] === $arFirst[$k]))
					unset($arDictionary[$k]);
			}
		}
	}
	return $arDictCollection;
}