inc/classes/main/stacker/file/class_BaseFileStack.php

   1 <?php
   2 /**
   3  * A general file-based stack class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   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
  10  *
  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.
  15  *
  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.
  20  *
  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/>.
  23  */
  24 class BaseFileStack extends BaseStacker {
  25         /**
  26          * Magic for this stack
  27          */
  28         const STACK_MAGIC = 'STACKv0.1';
  29
  30         /**
  31          * Separator magic->count
  32          */
  33         const SEPARATOR_MAGIC_COUNT = 0x00;
  34
  35         /**
  36          * Separator position->entries
  37          */
  38         const SEPARATOR_SEEK_POS_ENTRIES = 0xff;
  39
  40         /**
  41          * Separator hash->name
  42          */
  43         const SEPARATOR_HASH_NAME = 0x05;
  44
  45         /**
  46          * Length of count
  47          */
  48         const COUNT_LENGTH = 20;
  49
  50         /**
  51          * Length of position
  52          */
  53         const COUNT_POSITION = 20;
  54
  55         /**
  56          * Counter for total entries
  57          */
  58         private $totalEntries = 0;
  59
  60         /**
  61          * Current seek position
  62          */
  63         private $seekPosition = 0;
  64
  65         /**
  66          * Protected constructor
  67          *
  68          * @param       $className      Name of the class
  69          * @return      void
  70          */
  71         protected function __construct ($className) {
  72                 // Call parent constructor
  73                 parent::__construct($className);
  74         }
  75
  76         /**
  77          * Getter for total entries
  78          *
  79          * @return      $totalEntries   Total entries in this stack
  80          */
  81         private function getCounter () {
  82                 // Get it
  83                 return $this->totalEntries;
  84         }
  85
  86         /**
  87          * Increment counter
  88          *
  89          * @return      void
  90          */
  91         private function incrementCounter () {
  92                 // Get it
  93                 $this->totalEntries++;
  94         }
  95
  96         /**
  97          * Getter for seek position
  98          *
  99          * @return      $seekPosition   Current seek position (stored here in object)
 100          */
 101         private function getSeekPosition () {
 102                 // Get it
 103                 return $this->seekPosition;
 104         }
 105
 106         /**
 107          * Setter for seek position
 108          *
 109          * @param       $seekPosition   Current seek position (stored here in object)
 110          * @return      void
 111          */
 112         private function setSeekPosition ($seekPosition) {
 113                 // And set it
 114                 $this->seekPosition = $seekPosition;
 115         }
 116
 117         /**
 118          * Updates seekPosition attribute from file to avoid to much access on file.
 119          *
 120          * @return      void
 121          */
 122         private function updateSeekPosition () {
 123                 // Get key (= seek position)
 124                 $seekPosition = $this->getIteratorInstance()->key();
 125
 126                 // And set it here
 127                 $this->setSeekPosition($seekPosition);
 128         }
 129
 130         /**
 131          * Checks whether the file header is initialized
 132          *
 133          * @return      $isInitialized  Whether the file header is initialized
 134          */
 135         private function isFileHeaderInitialized () {
 136                 // Default is not initialized
 137                 $isInitialized = FALSE;
 138
 139                 // Is the file initialized?
 140                 if ($this->isFileInitialized()) {
 141                         // Some bytes has been written, so rewind to start of it.
 142                         $this->getIteratorInstance()->rewind();
 143
 144                         // Read file header
 145                         $this->readFileHeader();
 146                 } // END - if
 147
 148                 // Return result
 149                 return $isInitialized;
 150         }
 151
 152         /**
 153          * Checks whether the file-based stack has been initialized
 154          *
 155          * @return      $isInitialized          Whether the file's size is zero
 156          */
 157         private function isFileInitialized () {
 158                 // Get it from iterator which holds the pointer instance. If FALSE is returned
 159                 $fileSize = $this->getIteratorInstance()->size();
 160
 161                 /*
 162                  * The returned file size should not be FALSE or NULL as this means
 163                  * that the pointer class does not work correctly.
 164                  */
 165                 assert(is_int($fileSize));
 166
 167                 // Is more than 0 returned?
 168                 $isInitialized = ($fileSize > 0);
 169
 170                 // Return result
 171                 return $isInitialized;
 172         }
 173
 174         /**
 175          * Creates the file-stack's header
 176          *
 177          * @return      void
 178          */
 179         private function createFileHeader () {
 180                 // The file's header should not be initialized here
 181                 assert(!$this->isFileHeaderInitialized());
 182
 183                 // Flush file header
 184                 $this->flushFileHeader();
 185         }
 186
 187         /**
 188          * Flushes the file header
 189          *
 190          * @return      void
 191          */
 192         private function flushFileHeader () {
 193                 // Put all informations together
 194                 $header = sprintf('%s%s%s%s%s',
 195                         // Magic
 196                         self::STACK_MAGIC,
 197
 198                         // Separator magic<->count
 199                         chr(self::SEPARATOR_MAGIC_COUNT),
 200
 201                         // Total entries (will be zero) and pad it to 20 chars
 202                         str_pad($this->dec2hex($this->getCounter()), self::COUNT_LENGTH, '0', STR_PAD_LEFT),
 203
 204                         // Position (will be zero)
 205                         str_pad($this->dec2hex(0, 2), self::COUNT_POSITION, '0', STR_PAD_LEFT),
 206
 207                         // Separator position<->entries
 208                         chr(self::SEPARATOR_SEEK_POS_ENTRIES)
 209                 );
 210
 211                 // Write it to disk (header is always at seek position 0)
 212                 $this->getIteratorInstance()->writeAtPosition(0, $header);
 213
 214                 // Update seek position
 215                 $this->updateSeekPosition();
 216         }
 217
 218         /**
 219          * Initializes this file-based stack.
 220          *
 221          * @param       $fileName       File name of this stack
 222          * @return      void
 223          */
 224         protected function initFileStack ($fileName) {
 225                 // Get a file i/o pointer instance
 226                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 227
 228                 // Get iterator instance
 229                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
 230
 231                 // Is the instance implementing the right interface?
 232                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 233
 234                 // Set iterator here
 235                 $this->setIteratorInstance($iteratorInstance);
 236
 237                 // Is the file's header initialized?
 238                 if ($this->isFileHeaderInitialized()) {
 239                         // Then load it
 240                         $this->loadFileHeader();
 241                 } else {
 242                         // No, then create it (which may pre-allocate the stack)
 243                         $this->createFileHeader();
 244
 245                         // And pre-allocate a bit
 246                         $this->preAllocateFile();
 247                 }
 248         }
 249
 250         /**
 251          * Initializes given stacker
 252          *
 253          * @param       $stackerName    Name of the stack
 254          * @param       $forceReInit    Force re-initialization
 255          * @return      void
 256          * @throws      AlreadyInitializedStackerException      If the stack is already initialized
 257          */
 258         public function initStack ($stackerName, $forceReInit = FALSE) {
 259                 // Is the stack already initialized?
 260                 if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
 261                         // Then throw the exception
 262                         throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
 263                 } // END - if
 264
 265                 // Initialize the given stack
 266                 $this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
 267         }
 268
 269         /**
 270          * Checks whether the given stack is initialized (set in array $stackers)
 271          *
 272          * @param       $stackerName    Name of the stack
 273          * @return      $isInitialized  Whether the stack is initialized
 274          */
 275         public function isStackInitialized ($stackerName) {
 276                 // Is is there?
 277                 $this->partialStub('stackerName=' . $stackerName);
 278                 $isInitialized = TRUE;
 279
 280                 // Return result
 281                 return $isInitialized;
 282         }
 283
 284         /**
 285          * Getter for size of given stack (array count)
 286          *
 287          * @param       $stackerName    Name of the stack
 288          * @return      $count                  Size of stack (array count)
 289          * @throws      NoStackerException      If given stack is missing
 290          */
 291         public function getStackCount ($stackerName) {
 292                 // Is the stack not yet initialized?
 293                 if (!$this->isStackInitialized($stackerName)) {
 294                         // Throw an exception
 295                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 296                 } // END - if
 297
 298                 // Now, count the array of entries
 299                 $this->partialStub('stackerName=' . $stackerName);
 300                 $count = 0;
 301
 302                 // Return result
 303                 return $count;
 304         }
 305
 306         /**
 307          * Adds a value to given stack
 308          *
 309          * @param       $stackerName    Name of the stack
 310          * @param       $value                  Value to add to this stacker
 311          * @return      void
 312          * @throws      FullStackerException    Thrown if the stack is full
 313          */
 314         protected function addValue ($stackerName, $value) {
 315                 // Is the stack not yet initialized or full?
 316                 if (!$this->isStackInitialized($stackerName)) {
 317                         // Then do it here
 318                         $this->initStack($stackerName);
 319                 } elseif ($this->isStackFull($stackerName)) {
 320                         // Stacker is full
 321                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 322                 }
 323
 324                 // Now add the value to the stack
 325                 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
 326         }
 327
 328         /**
 329          * Get last value from named stacker
 330          *
 331          * @param       $stackerName    Name of the stack
 332          * @return      $value                  Value of last added value
 333          * @throws      NoStackerException      If the named stacker was not found
 334          * @throws      EmptyStackerException   If the named stacker is empty
 335          */
 336         protected function getLastValue ($stackerName) {
 337                 // Is the stack not yet initialized or full?
 338                 if (!$this->isStackInitialized($stackerName)) {
 339                         // Throw an exception
 340                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 341                 } elseif ($this->isStackEmpty($stackerName)) {
 342                         // Throw an exception
 343                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 344                 }
 345
 346                 // Now get the last value
 347                 $this->partialStub('stackerName=' . $stackerName);
 348                 $value = NULL;
 349
 350                 // Return it
 351                 return $value;
 352         }
 353
 354         /**
 355          * Get first value from named stacker
 356          *
 357          * @param       $stackerName    Name of the stack
 358          * @return      $value                  Value of last added value
 359          * @throws      NoStackerException      If the named stacker was not found
 360          * @throws      EmptyStackerException   If the named stacker is empty
 361          */
 362         protected function getFirstValue ($stackerName) {
 363                 // Is the stack not yet initialized or full?
 364                 if (!$this->isStackInitialized($stackerName)) {
 365                         // Throw an exception
 366                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 367                 } elseif ($this->isStackEmpty($stackerName)) {
 368                         // Throw an exception
 369                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 370                 }
 371
 372                 // Now get the first value
 373                 $this->partialStub('stackerName=' . $stackerName);
 374                 $value = NULL;
 375
 376                 // Return it
 377                 return $value;
 378         }
 379
 380         /**
 381          * "Pops" last entry from stack
 382          *
 383          * @param       $stackerName    Name of the stack
 384          * @return      $value                  Value "poped" from array
 385          * @throws      NoStackerException      If the named stacker was not found
 386          * @throws      EmptyStackerException   If the named stacker is empty
 387          */
 388         protected function popLast ($stackerName) {
 389                 // Is the stack not yet initialized or full?
 390                 if (!$this->isStackInitialized($stackerName)) {
 391                         // Throw an exception
 392                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 393                 } elseif ($this->isStackEmpty($stackerName)) {
 394                         // Throw an exception
 395                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 396                 }
 397
 398                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 399                 $this->partialStub('stackerName=' . $stackerName);
 400                 return NULL;
 401         }
 402
 403         /**
 404          * "Pops" first entry from stack
 405          *
 406          * @param       $stackerName    Name of the stack
 407          * @return      $value                  Value "shifted" from array
 408          * @throws      NoStackerException      If the named stacker was not found
 409          * @throws      EmptyStackerException   If the named stacker is empty
 410          */
 411         protected function popFirst ($stackerName) {
 412                 // Is the stack not yet initialized or full?
 413                 if (!$this->isStackInitialized($stackerName)) {
 414                         // Throw an exception
 415                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 416                 } elseif ($this->isStackEmpty($stackerName)) {
 417                         // Throw an exception
 418                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 419                 }
 420
 421                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 422                 $this->partialStub('stackerName=' . $stackerName);
 423                 return NULL;
 424         }
 425 }
 426
 427 // [EOF]
 428 ?>