3 * A general index class
5 * @author Roland Haeder <webmaster@ship-simu.org>
7 * @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 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 BaseIndex extends BaseFrameworkSystem {
26 * Magic for this index
28 const INDEX_MAGIC = 'INDEXv0.1';
31 * Separator for header data
33 const SEPARATOR_HEADER_DATA = 0x01;
36 * Separator header->entries
38 const SEPARATOR_HEADER_ENTRIES = 0x02;
41 * Protected constructor
43 * @param $className Name of the class
46 protected function __construct ($className) {
47 // Call parent constructor
48 parent::__construct($className);
50 // Calculate header size
52 strlen(self::INDEX_MAGIC) +
53 strlen(self::SEPARATOR_HEADER_DATA) +
55 strlen(self::SEPARATOR_HEADER_ENTRIES)
60 * Reads the file header
64 private function readFileHeader () {
65 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
67 // First rewind to beginning as the header sits at the beginning ...
68 $this->getIteratorInstance()->rewind();
70 // Then read it (see constructor for calculation)
71 $data = $this->getIteratorInstance()->read($this->headerSize);
72 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->headerSize));
74 // Have all requested bytes been read?
75 assert(strlen($data) == $this->headerSize);
76 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
78 // Last character must be the separator
79 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
80 assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
81 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
83 // Okay, then remove it
84 $data = substr($data, 0, -1);
86 // And update seek position
87 $this->updateSeekPosition();
95 $this->header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
97 // Check if the array has only 3 elements
98 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($this->header), print_r($this->header, TRUE)));
99 assert(count($this->header) == 2);
100 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
103 assert($this->header[0] == self::INDEX_MAGIC);
104 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
106 // Check length of count
107 assert(strlen($this->header[1]) == self::LENGTH_COUNT);
108 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
111 $this->header[1] = hex2bin($this->header[1]);
113 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
117 * Checks whether the file header is initialized
119 * @return $isInitialized Whether the file header is initialized
121 private function isFileHeaderInitialized () {
122 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
123 // Default is not initialized
124 $isInitialized = FALSE;
126 // Is the file initialized?
127 if ($this->isFileInitialized()) {
128 // Some bytes has been written, so rewind to start of it.
129 $rewindStatus = $this->getIteratorInstance()->rewind();
130 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
132 // Is the rewind() call successfull?
133 if ($rewindStatus != 1) {
134 // Something bad happened
135 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Could not rewind().', __METHOD__, __LINE__));
139 $this->readFileHeader();
141 // The above method does already check the header
142 $isInitialized = TRUE;
146 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
147 return $isInitialized;
151 * Flushes the file header
155 private function flushFileHeader () {
156 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
158 // Put all informations together
159 $header = sprintf('%s%s',
163 // Separator position<->entries
164 chr(self::SEPARATOR_HEADER_ENTRIES)
167 // Write it to disk (header is always at seek position 0)
168 $this->writeData(0, $header);
170 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
174 * Analyzes entries in index file. This will count all found (and valid)
175 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
176 * only gaps are found, the file is considered as "virgin" (no entries).
180 private function analyzeFile () {
181 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
183 // Make sure the file is initialized
184 assert($this->isFileInitialized());
186 // Init counters and gaps array
187 $this->initGapsArray();
189 // Output message (as this may take some time)
190 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
192 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
196 * Initializes this index
198 * @param $fileName File name of this index
201 protected function initIndex ($fileName) {
202 // Get a file i/o pointer instance for index file
203 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
205 // Get iterator instance
206 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
208 // Is the instance implementing the right interface?
209 assert($iteratorInstance instanceof SeekableWritableFileIterator);
212 $this->setIteratorInstance($iteratorInstance);
214 // Is the file's header initialized?
215 if (!$this->isFileHeaderInitialized()) {
216 // No, then create it (which may pre-allocate the index)
217 $this->createFileHeader();
219 // And pre-allocate a bit
220 $this->preAllocateFile('index');
223 // Load the file header
224 $this->readFileHeader();
226 // Count all entries in file
227 $this->analyzeFile();