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 private 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 $this->header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
113 // Check if the array has only 3 elements
114 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($this->header), print_r($this->header, TRUE)));
115 assert(count($this->header) == 3);
116 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
119 assert($this->header[0] == self::STACK_MAGIC);
120 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
122 // Check length of count and seek position
123 assert(strlen($this->header[1]) == self::LENGTH_COUNT);
124 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
125 assert(strlen($this->header[2]) == self::LENGTH_POSITION);
126 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
128 // Decode count and seek position
129 $this->header[1] = hex2bin($this->header[1]);
130 $this->header[2] = hex2bin($this->header[2]);
132 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
136 * Flushes the file header
140 private function flushFileHeader () {
141 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
143 // Put all informations together
144 $header = sprintf('%s%s%s%s%s%s',
148 // Separator magic<->count
149 chr(self::SEPARATOR_HEADER_DATA),
151 // Total entries (will be zero) and pad it to 20 chars
152 str_pad($this->dec2hex($this->getCounter()), self::LENGTH_COUNT, '0', STR_PAD_LEFT),
154 // Separator count<->seek position
155 chr(self::SEPARATOR_HEADER_DATA),
157 // Position (will be zero)
158 str_pad($this->dec2hex($this->getSeekPosition(), 2), self::LENGTH_POSITION, '0', STR_PAD_LEFT),
160 // Separator position<->entries
161 chr(self::SEPARATOR_HEADER_ENTRIES)
164 // Write it to disk (header is always at seek position 0)
165 $this->writeData(0, $header);
167 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
171 * Analyzes entries in stack file. This will count all found (and valid)
172 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
173 * only gaps are found, the file is considered as "virgin" (no entries).
177 private function analyzeFile () {
178 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
180 // Make sure the file is initialized
181 assert($this->isFileInitialized());
183 // Init counters and gaps array
184 $this->initCountersGapsArray();
186 // Output message (as this may take some time)
187 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
189 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
193 * Initializes this file-based stack.
195 * @param $fileName File name of this stack
196 * @param $type Type of this stack (e.g. url_source for URL sources)
199 protected function initFileStack ($fileName, $type) {
200 // Get a file i/o pointer instance for stack file
201 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
203 // Get iterator instance
204 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
206 // Is the instance implementing the right interface?
207 assert($iteratorInstance instanceof SeekableWritableFileIterator);
210 $this->setIteratorInstance($iteratorInstance);
212 // Is the file's header initialized?
213 if (!$this->isFileHeaderInitialized()) {
214 // No, then create it (which may pre-allocate the stack)
215 $this->createFileHeader();
217 // And pre-allocate a bit
218 $this->preAllocateFile('file_stack');
221 // Load the file header
222 $this->readFileHeader();
224 // Count all entries in file
225 $this->analyzeFile();
228 * Get stack index instance. This can be used for faster
229 * "defragmentation" and startup.
231 $indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileName, $type);
234 $this->setIndexInstance($indexInstance);
238 * Adds a value to given stack
240 * @param $stackerName Name of the stack
241 * @param $value Value to add to this stacker
243 * @throws FullStackerException If the stack is full
245 protected function addValue ($stackerName, $value) {
247 if ($this->isStackFull($stackerName)) {
249 throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
252 // Now add the value to the stack
253 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
257 * Get last value from named stacker
259 * @param $stackerName Name of the stack
260 * @return $value Value of last added value
261 * @throws EmptyStackerException If the stack is empty
263 protected function getLastValue ($stackerName) {
264 // Is the stack not yet initialized or full?
265 if ($this->isStackEmpty($stackerName)) {
266 // Throw an exception
267 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
270 // Now get the last value
271 $this->partialStub('stackerName=' . $stackerName);
279 * Get first value from named stacker
281 * @param $stackerName Name of the stack
282 * @return $value Value of last added value
283 * @throws EmptyStackerException If the stack is empty
285 protected function getFirstValue ($stackerName) {
286 // Is the stack not yet initialized or full?
287 if ($this->isStackEmpty($stackerName)) {
288 // Throw an exception
289 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
292 // Now get the first value
293 $this->partialStub('stackerName=' . $stackerName);
301 * "Pops" last entry from stack
303 * @param $stackerName Name of the stack
304 * @return $value Value "poped" from array
305 * @throws EmptyStackerException If the stack is empty
307 protected function popLast ($stackerName) {
308 // Is the stack not yet initialized or full?
309 if ($this->isStackEmpty($stackerName)) {
310 // Throw an exception
311 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
314 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
315 $this->partialStub('stackerName=' . $stackerName);
320 * "Pops" first entry from stack
322 * @param $stackerName Name of the stack
323 * @return $value Value "shifted" from array
324 * @throws EmptyStackerException If the named stacker is empty
326 protected function popFirst ($stackerName) {
327 // Is the stack not yet initialized or full?
328 if ($this->isStackEmpty($stackerName)) {
329 // Throw an exception
330 throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
333 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
334 $this->partialStub('stackerName=' . $stackerName);
339 * Checks whether the given stack is full
341 * @param $stackerName Name of the stack
342 * @return $isFull Whether the stack is full
344 protected function isStackFull ($stackerName) {
345 // File-based stacks will only run full if the disk space is low.
346 // @TODO Please implement this, returning FALSE
354 * Checks whether the given stack is empty
356 * @param $stackerName Name of the stack
357 * @return $isEmpty Whether the stack is empty
358 * @throws NoStackerException If given stack is missing
360 public function isStackEmpty ($stackerName) {
361 // So, is the stack empty?
362 $isEmpty = (($this->getStackCount($stackerName)) == 0);
369 * Initializes given stacker
371 * @param $stackerName Name of the stack
372 * @param $forceReInit Force re-initialization
374 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
376 public function initStack ($stackerName, $forceReInit = FALSE) {
377 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
381 * Initializes all stacks
384 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
386 public function initStacks (array $stacks, $forceReInit = FALSE) {
387 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
391 * Checks whether the given stack is initialized (set in array $stackers)
393 * @param $stackerName Name of the stack
394 * @return $isInitialized Whether the stack is initialized
395 * @throws UnsupportedOperationException This method is not (and maybe never will be) supported
397 public function isStackInitialized ($stackerName) {
398 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
402 * Getter for size of given stack (array count)
404 * @param $stackerName Name of the stack
405 * @return $count Size of stack (array count)
407 public function getStackCount ($stackerName) {
408 // Now, simply return the found count value, this must be up-to-date then!
409 return $this->getCounter();