3 * A general file-based stack class
5 * @author Roland Haeder <webmaster@ship-simu.org>
7 * @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2013 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 BaseFileStack extends BaseStacker {
26 * Magic for this stack
28 const STACK_MAGIC = 'STACKv0.1';
31 * Separator magic->count
33 const SEPARATOR_MAGIC_COUNT = 0x00;
36 * Separator position->entries
38 const SEPARATOR_SEEK_POS_ENTRIES = 0xff;
41 * Separator hash->name
43 const SEPARATOR_HASH_NAME = 0x05;
48 const COUNT_LENGTH = 20;
53 const COUNT_POSITION = 20;
56 * Counter for total entries
58 private $totalEntries = 0;
61 * Current seek position
63 private $seekPosition = 0;
66 * Protected constructor
68 * @param $className Name of the class
71 protected function __construct ($className) {
72 // Call parent constructor
73 parent::__construct($className);
77 * Getter for total entries
79 * @return $totalEntries Total entries in this stack
81 private function getCounter () {
83 return $this->totalEntries;
91 private function incrementCounter () {
93 $this->totalEntries++;
97 * Getter for seek position
99 * @return $seekPosition Current seek position (stored here in object)
101 private function getSeekPosition () {
103 return $this->seekPosition;
107 * Setter for seek position
109 * @param $seekPosition Current seek position (stored here in object)
112 private function setSeekPosition ($seekPosition) {
114 $this->seekPosition = $seekPosition;
118 * Updates seekPosition attribute from file to avoid to much access on file.
122 private function updateSeekPosition () {
123 // Get key (= seek position)
124 $seekPosition = $this->getIteratorInstance()->key();
127 $this->setSeekPosition($seekPosition);
131 * Checks whether the file header is initialized
133 * @return $isInitialized Whether the file header is initialized
135 private function isFileHeaderInitialized () {
136 // Default is not initialized
137 $isInitialized = FALSE;
139 // Is the file initialized?
140 if ($this->isFileInitialized()) {
141 // Some bytes has been written, so rewind to start of it.
142 $this->getIteratorInstance()->rewind();
145 $this->readFileHeader();
149 return $isInitialized;
153 * Checks whether the file-based stack has been initialized
155 * @return $isInitialized Whether the file's size is zero
157 private function isFileInitialized () {
158 // Default is not initialized
159 $isInitialized = FALSE;
161 // Get it from iterator which holds the pointer instance. If FALSE is returned
162 $fileSize = $this->getIteratorInstance()->size();
165 * The returned file size should not be FALSE or NULL as this means
166 * that the pointer class does not work correctly.
168 assert(is_int($fileSize));
170 // Is more than 0 returned?
172 // So is the header written?
173 $isInitialized = $this->getIteratorInstance()->isHeaderInitialized();
177 return $isInitialized;
181 * Creates the file-stack's header
185 private function createFileHeader () {
186 // The file's header should not be initialized here
187 assert(!$this->isFileHeaderInitialized());
190 $this->flushFileHeader();
194 * Flushes the file header
198 private function flushFileHeader () {
199 // Put all informations together
200 $header = sprintf('%s%s%s%s%s',
204 // Separator magic<->count
205 chr(self::SEPARATOR_MAGIC_COUNT),
207 // Total entries (will be zero) and pad it to 20 chars
208 str_pad($this->dec2hex($this->getCounter()), self::COUNT_LENGTH, '0', STR_PAD_LEFT),
210 // Position (will be zero)
211 str_pad($this->dec2hex(0, 2), self::COUNT_POSITION, '0', STR_PAD_LEFT),
213 // Separator position<->entries
214 chr(self::SEPARATOR_SEEK_POS_ENTRIES)
217 // Write it to disk (header is always at seek position 0)
218 $this->getIteratorInstance()->writeAtPosition(0, $header);
220 // Update seek position
221 $this->updateSeekPosition();
225 * Initializes this file-based stack.
227 * @param $fileName File name of this stack
230 protected function initFileStack ($fileName) {
231 // Get a file i/o pointer instance
232 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
234 // Get iterator instance
235 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
237 // Is the instance implementing the right interface?
238 assert($iteratorInstance instanceof SeekableWritableFileIterator);
241 $this->setIteratorInstance($iteratorInstance);
243 // Is the file's header initialized?
244 if ($this->isFileHeaderInitialized()) {
246 $this->loadFileHeader();
248 // No, then create it (which may pre-allocate the stack)
249 $this->createFileHeader();
251 // And pre-allocate a bit
252 $this->preAllocateFile();
257 * Initializes given stacker
259 * @param $stackerName Name of the stack
260 * @param $forceReInit Force re-initialization
262 * @throws AlreadyInitializedStackerException If the stack is already initialized
264 public function initStack ($stackerName, $forceReInit = FALSE) {
265 // Is the stack already initialized?
266 if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
267 // Then throw the exception
268 throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
271 // Initialize the given stack
272 $this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
276 * Checks whether the given stack is initialized (set in array $stackers)
278 * @param $stackerName Name of the stack
279 * @return $isInitialized Whether the stack is initialized
281 public function isStackInitialized ($stackerName) {
283 $this->partialStub('stackerName=' . $stackerName);
284 $isInitialized = TRUE;
287 return $isInitialized;
291 * Getter for size of given stack (array count)
293 * @param $stackerName Name of the stack
294 * @return $count Size of stack (array count)
295 * @throws NoStackerException If given stack is missing
297 public function getStackCount ($stackerName) {
298 // Is the stack not yet initialized?
299 if (!$this->isStackInitialized($stackerName)) {
300 // Throw an exception
301 throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
304 // Now, count the array of entries
305 $this->partialStub('stackerName=' . $stackerName);
313 * Adds a value to given stack
315 * @param $stackerName Name of the stack
316 * @param $value Value to add to this stacker
318 * @throws FullStackerException Thrown if the stack is full
320 protected function addValue ($stackerName, $value) {
321 // Is the stack not yet initialized or full?
322 if (!$this->isStackInitialized($stackerName)) {
324 $this->initStack($stackerName);
325 } elseif ($this->isStackFull($stackerName)) {
327 throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
330 // Now add the value to the stack
331 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
335 * Get last value from named stacker
337 * @param $stackerName Name of the stack
338 * @return $value Value of last added value
339 * @throws NoStackerException If the named stacker was not found
340 * @throws EmptyStackerException If the named stacker is empty
342 protected function getLastValue ($stackerName) {
343 // Is the stack not yet initialized or full?
344 if (!$this->isStackInitialized($stackerName)) {
345 // Throw an exception
346 throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
347 } elseif ($this->isStackEmpty($stackerName)) {
348 // Throw an exception
349 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
352 // Now get the last value
353 $this->partialStub('stackerName=' . $stackerName);
361 * Get first value from named stacker
363 * @param $stackerName Name of the stack
364 * @return $value Value of last added value
365 * @throws NoStackerException If the named stacker was not found
366 * @throws EmptyStackerException If the named stacker is empty
368 protected function getFirstValue ($stackerName) {
369 // Is the stack not yet initialized or full?
370 if (!$this->isStackInitialized($stackerName)) {
371 // Throw an exception
372 throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
373 } elseif ($this->isStackEmpty($stackerName)) {
374 // Throw an exception
375 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
378 // Now get the first value
379 $this->partialStub('stackerName=' . $stackerName);
387 * "Pops" last entry from stack
389 * @param $stackerName Name of the stack
390 * @return $value Value "poped" from array
391 * @throws NoStackerException If the named stacker was not found
392 * @throws EmptyStackerException If the named stacker is empty
394 protected function popLast ($stackerName) {
395 // Is the stack not yet initialized or full?
396 if (!$this->isStackInitialized($stackerName)) {
397 // Throw an exception
398 throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
399 } elseif ($this->isStackEmpty($stackerName)) {
400 // Throw an exception
401 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
404 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
405 $this->partialStub('stackerName=' . $stackerName);
410 * "Pops" first entry from stack
412 * @param $stackerName Name of the stack
413 * @return $value Value "shifted" from array
414 * @throws NoStackerException If the named stacker was not found
415 * @throws EmptyStackerException If the named stacker is empty
417 protected function popFirst ($stackerName) {
418 // Is the stack not yet initialized or full?
419 if (!$this->isStackInitialized($stackerName)) {
420 // Throw an exception
421 throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
422 } elseif ($this->isStackEmpty($stackerName)) {
423 // Throw an exception
424 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
427 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
428 $this->partialStub('stackerName=' . $stackerName);