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)
58 // Init counters and gaps array
59 $this->initCountersGapsArray();
63 * Reads the file header
67 protected function readFileHeader () {
68 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
70 // First rewind to beginning as the header sits at the beginning ...
71 $this->getIteratorInstance()->rewind();
73 // Then read it (see constructor for calculation)
74 $data = $this->getIteratorInstance()->read($this->getHeaderSize());
75 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->getHeaderSize()));
77 // Have all requested bytes been read?
78 assert(strlen($data) == $this->getHeaderSize());
79 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
81 // Last character must be the separator
82 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
83 assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
84 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
86 // Okay, then remove it
87 $data = substr($data, 0, -1);
89 // And update seek position
90 $this->updateSeekPosition();
98 $header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
101 $this->setHeader($header);
103 // Check if the array has only 3 elements
104 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($header), print_r($header, TRUE)));
105 assert(count($header) == 2);
106 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
109 assert($header[0] == self::INDEX_MAGIC);
110 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
112 // Check length of count
113 assert(strlen($header[1]) == self::LENGTH_COUNT);
114 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
117 $header[1] = hex2bin($header[1]);
119 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
123 * Flushes the file header
127 protected function flushFileHeader () {
128 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
130 // Put all informations together
131 $header = sprintf('%s%s%s%s',
135 // Separator header data
136 chr(self::SEPARATOR_HEADER_DATA),
139 str_pad($this->dec2hex($this->getCounter()), self::LENGTH_COUNT, '0', STR_PAD_LEFT),
141 // Separator header<->entries
142 chr(self::SEPARATOR_HEADER_ENTRIES)
145 // Write it to disk (header is always at seek position 0)
146 $this->writeData(0, $header, FALSE);
148 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
152 * Analyzes entries in index file. This will count all found (and valid)
153 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
154 * only gaps are found, the file is considered as "virgin" (no entries).
158 private function analyzeFile () {
159 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
161 // Make sure the file is initialized
162 assert($this->isFileInitialized());
164 // Init counters and gaps array
165 $this->initCountersGapsArray();
167 // Output message (as this may take some time)
168 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
170 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
174 * Calculates minimum length for one entry
176 * @return $length Minimum length for one entry
178 protected function caluclateMinimumFileEntryLength () {
180 // @TODO Not finished yet
188 * Initializes this index
190 * @param $fileName File name of this index
192 * @todo Currently the index file is not cached, please implement a memory-handling class and if enough RAM is found, cache the whole index file.
194 protected function initIndex ($fileName) {
195 // Append index file extension
196 $fileName .= $this->getConfigInstance()->getConfigEntry('index_extension');
198 // Get a file i/o pointer instance for index file
199 $fileInstance = ObjectFactory::createObjectByConfiguredName('index_file_class', array($fileName));
201 // Get iterator instance
202 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($fileInstance));
204 // Is the instance implementing the right interface?
205 assert($iteratorInstance instanceof SeekableWritableFileIterator);
208 $this->setIteratorInstance($iteratorInstance);
210 // Is the file's header initialized?
211 if (!$this->isFileHeaderInitialized()) {
212 // No, then create it (which may pre-allocate the index)
213 $this->createFileHeader();
215 // And pre-allocate a bit
216 $this->preAllocateFile('index');
219 // Load the file header
220 $this->readFileHeader();
222 // Count all entries in file
223 $this->analyzeFile();