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 for header data
33 const SEPARATOR_HEADER_DATA = 0x01;
36 * Separator header->entries
38 const SEPARATOR_HEADER_ENTRIES = 0x02;
41 * Separator hash->name
43 const SEPARATOR_HASH_NAME = 0x03;
48 const LENGTH_NAME = 10;
51 * Protected constructor
53 * @param $className Name of the class
56 protected function __construct ($className) {
57 // Call parent constructor
58 parent::__construct($className);
60 // Calculate header size
62 strlen(self::STACK_MAGIC) +
63 strlen(self::SEPARATOR_HEADER_DATA) +
65 strlen(self::SEPARATOR_HEADER_DATA) +
66 self::LENGTH_POSITION +
67 strlen(self::SEPARATOR_HEADER_ENTRIES)
70 // Init counters and gaps array
71 $this->initCountersGapsArray();
75 * Reads the file header
79 protected function readFileHeader () {
80 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
82 // First rewind to beginning as the header sits at the beginning ...
83 $this->getIteratorInstance()->rewind();
85 // Then read it (see constructor for calculation)
86 $data = $this->getIteratorInstance()->read($this->getHeaderSize());
87 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->getHeaderSize()));
89 // Have all requested bytes been read?
90 assert(strlen($data) == $this->getHeaderSize());
91 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
93 // Last character must be the separator
94 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
95 assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
96 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
98 // Okay, then remove it
99 $data = substr($data, 0, -1);
101 // And update seek position
102 $this->updateSeekPosition();
109 * 2 => current seek position
111 $header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
114 $this->setHeader($header);
116 // Check if the array has only 3 elements
117 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($header), print_r($header, TRUE)));
118 assert(count($header) == 3);
119 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
122 assert($header[0] == self::STACK_MAGIC);
123 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
125 // Check length of count and seek position
126 assert(strlen($header[1]) == self::LENGTH_COUNT);
127 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
128 assert(strlen($header[2]) == self::LENGTH_POSITION);
129 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
131 // Decode count and seek position
132 $header[1] = hex2bin($header[1]);
133 $header[2] = hex2bin($header[2]);
135 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
139 * Flushes the file header
143 private function flushFileHeader () {
144 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
146 // Put all informations together
147 $header = sprintf('%s%s%s%s%s%s',
151 // Separator magic<->count
152 chr(self::SEPARATOR_HEADER_DATA),
154 // Total entries (will be zero) and pad it to 20 chars
155 str_pad($this->dec2hex($this->getCounter()), self::LENGTH_COUNT, '0', STR_PAD_LEFT),
157 // Separator count<->seek position
158 chr(self::SEPARATOR_HEADER_DATA),
160 // Position (will be zero)
161 str_pad($this->dec2hex($this->getSeekPosition(), 2), self::LENGTH_POSITION, '0', STR_PAD_LEFT),
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, $header);
170 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
174 * Analyzes entries in stack file. This will count all found (and valid)
175 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
176 * only gaps are found, the file is considered as "virgin" (no entries).
180 private function analyzeFile () {
181 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
183 // Make sure the file is initialized
184 assert($this->isFileInitialized());
186 // Init counters and gaps array
187 $this->initCountersGapsArray();
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 file-based stack.
198 * @param $fileName File name of this stack
199 * @param $type Type of this stack (e.g. url_source for URL sources)
202 protected function initFileStack ($fileName, $type) {
203 // Get a file i/o pointer instance for stack file
204 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
206 // Get iterator instance
207 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
209 // Is the instance implementing the right interface?
210 assert($iteratorInstance instanceof SeekableWritableFileIterator);
213 $this->setIteratorInstance($iteratorInstance);
215 // Is the file's header initialized?
216 if (!$this->isFileHeaderInitialized()) {
217 // No, then create it (which may pre-allocate the stack)
218 $this->createFileHeader();
220 // And pre-allocate a bit
221 $this->preAllocateFile('file_stack');
224 // Load the file header
225 $this->readFileHeader();
227 // Count all entries in file
228 $this->analyzeFile();
231 * Get stack index instance. This can be used for faster
232 * "defragmentation" and startup.
234 $indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileName, $type);
237 $this->setIndexInstance($indexInstance);
241 * Adds a value to given stack
243 * @param $stackerName Name of the stack
244 * @param $value Value to add to this stacker
246 * @throws FullStackerException If the stack is full
248 protected function addValue ($stackerName, $value) {
250 if ($this->isStackFull($stackerName)) {
252 throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
255 // Now add the value to the stack
256 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
260 * Get last value from named stacker
262 * @param $stackerName Name of the stack
263 * @return $value Value of last added value
264 * @throws EmptyStackerException If the stack is empty
266 protected function getLastValue ($stackerName) {
267 // Is the stack not yet initialized or full?
268 if ($this->isStackEmpty($stackerName)) {
269 // Throw an exception
270 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
273 // Now get the last value
274 $this->partialStub('stackerName=' . $stackerName);
282 * Get first value from named stacker
284 * @param $stackerName Name of the stack
285 * @return $value Value of last added value
286 * @throws EmptyStackerException If the stack is empty
288 protected function getFirstValue ($stackerName) {
289 // Is the stack not yet initialized or full?
290 if ($this->isStackEmpty($stackerName)) {
291 // Throw an exception
292 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
295 // Now get the first value
296 $this->partialStub('stackerName=' . $stackerName);
304 * "Pops" last entry from stack
306 * @param $stackerName Name of the stack
307 * @return $value Value "poped" from array
308 * @throws EmptyStackerException If the stack is empty
310 protected function popLast ($stackerName) {
311 // Is the stack not yet initialized or full?
312 if ($this->isStackEmpty($stackerName)) {
313 // Throw an exception
314 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
317 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
318 $this->partialStub('stackerName=' . $stackerName);
323 * "Pops" first entry from stack
325 * @param $stackerName Name of the stack
326 * @return $value Value "shifted" from array
327 * @throws EmptyStackerException If the named stacker is empty
329 protected function popFirst ($stackerName) {
330 // Is the stack not yet initialized or full?
331 if ($this->isStackEmpty($stackerName)) {
332 // Throw an exception
333 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
336 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
337 $this->partialStub('stackerName=' . $stackerName);
342 * Checks whether the given stack is full
344 * @param $stackerName Name of the stack
345 * @return $isFull Whether the stack is full
347 protected function isStackFull ($stackerName) {
348 // File-based stacks will only run full if the disk space is low.
349 // @TODO Please implement this, returning FALSE
357 * Checks whether the given stack is empty
359 * @param $stackerName Name of the stack
360 * @return $isEmpty Whether the stack is empty
361 * @throws NoStackerException If given stack is missing
363 public function isStackEmpty ($stackerName) {
364 // So, is the stack empty?
365 $isEmpty = (($this->getStackCount($stackerName)) == 0);
372 * Initializes given stacker
374 * @param $stackerName Name of the stack
375 * @param $forceReInit Force re-initialization
377 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
379 public function initStack ($stackerName, $forceReInit = FALSE) {
380 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
384 * Initializes all stacks
387 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
389 public function initStacks (array $stacks, $forceReInit = FALSE) {
390 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
394 * Checks whether the given stack is initialized (set in array $stackers)
396 * @param $stackerName Name of the stack
397 * @return $isInitialized Whether the stack is initialized
398 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
400 public function isStackInitialized ($stackerName) {
401 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
405 * Getter for size of given stack (array count)
407 * @param $stackerName Name of the stack
408 * @return $count Size of stack (array count)
410 public function getStackCount ($stackerName) {
411 // Now, simply return the found count value, this must be up-to-date then!
412 return $this->getCounter();