5 * @author Roland Haeder <webmaster@ship-simu.org>
7 * @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2015 Core Developer Team
8 * @license GNU GPL 3.0 or any newer version
9 * @link http://www.ship-simu.org
11 * This program is free software: you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation, either version 3 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 class StackFile extends BaseBinaryFile implements Block {
26 * Protected constructor
30 protected function __construct () {
31 // Call parent constructor
32 parent::__construct(__CLASS__);
36 * Creates an instance of this File class and prepares it for usage
38 * @param $fileName Name of the stack file
39 * @param $blockInstance An instance of a Block class
40 * @return $fileInstance An instance of this File class
42 public final static function createStackFile ($fileName, Block $blockInstance) {
44 $fileInstance = new StackFile();
46 // Set block instance here for callbacks
47 $fileInstance->setBlockInstance($blockInstance);
49 // Init this abstract file
50 $fileInstance->initFile($fileName);
52 // Return the prepared instance
57 * Writes given value to the file and returns a hash and gap position for it
59 * @param $groupId Group identifier
60 * @param $value Value to be added to the stack
61 * @return $data Hash and gap position
63 public function writeValueToFile ($groupId, $value) {
64 // Make sure no objects/resources are added as the serialization may fail
65 assert(!is_object($value));
66 assert(!is_resource($value));
68 // Encode/convert the value into a "binary format"
69 $encoded = $this->encodeData($value);
71 // Get a strong hash for the "encoded" data
72 $hash = self::hash($encoded);
74 // Then write it to the next free gap
75 $data = $this->getBlockInstance()->writeDataToFreeGap($groupId, $hash, $encoded);
82 * Writes given raw data to the file and returns a gap position and length
84 * @param $groupId Group identifier
85 * @param $hash Hash from encoded value
86 * @param $encoded Encoded value to be written to the file
87 * @return $data Gap position and length of the raw data
88 * @throws UnsupportedOperationException If this method is called
90 public function writeDataToFreeGap ($groupId, $hash, $encoded) {
91 self::createDebugInstance(__CLASS__)->debugOutput('[' . __METHOD__ . ':' . __LINE__ . '] groupId=' . $groupId . ',hash=' . $hash . ',encoded()=' . strlen($encoded));
92 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);