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          * Protected constructor
  47          *
  48          * @param       $className      Name of the class
  49          * @return      void
  50          */
  51         protected function __construct ($className) {
  52                 // Call parent constructor
  53                 parent::__construct($className);
  54         }
  55
  56         /**
  57          * Checks whether the file header is initialized
  58          *
  59          * @return      $isInitialized  Whether the file header is initialized
  60          */
  61         private function isFileHeaderInitialized () {
  62                 // Default is not initialized
  63                 $isInitialized = FALSE;
  64
  65                 // Is the file initialized?
  66                 if ($this->isFileInitialized()) {
  67                         // Some bytes has been written, so rewind to start of it.
  68                         $this->getIteratorInstance()->rewind();
  69
  70                         // Read file header
  71                         $this->readFileHeader();
  72                 } // END - if
  73
  74                 // Return result
  75                 return $isInitialized;
  76         }
  77
  78         /**
  79          * Checks whether the file-based stack has been initialized
  80          *
  81          * @return      $isInitialized          Whether the file's size is zero
  82          */
  83         private function isFileInitialized () {
  84                 // Default is not initialized
  85                 $isInitialized = FALSE;
  86
  87                 // Get it from iterator which holds the pointer instance. If FALSE is returned
  88                 $fileSize = $this->getIteratorInstance()->size();
  89
  90                 /*
  91                  * The returned file size should not be FALSE or NULL as this means
  92                  * that the pointer class does not work correctly.
  93                  */
  94                 assert(is_int($fileSize));
  95
  96                 // Is more than 0 returned?
  97                 if ($fileSize > 0) {
  98                         // So is the header written?
  99                         $isInitialized = $this->getIteratorInstance()->isHeaderInitialized();
 100                 } // END - if
 101
 102                 // Return result
 103                 return $isInitialized;
 104         }
 105
 106         /**
 107          * Initializes this file-based stack.
 108          *
 109          * @param       $fileName       File name of this stack
 110          * @return      void
 111          */
 112         protected function initFileStack ($fileName) {
 113                 // Get a file i/o pointer instance
 114                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 115
 116                 // Get iterator instance
 117                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
 118
 119                 // Is the instance implementing the right interface?
 120                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 121
 122                 // Set iterator here
 123                 $this->setIteratorInstance($iteratorInstance);
 124
 125                 // Is the file's header initialized?
 126                 if ($this->isFileHeaderInitialized()) {
 127                         // Then load it
 128                         $this->loadFileHeader();
 129                 } else {
 130                         // No, then create it (which may pre-allocate the stack)
 131                         $this->createFileHeader();
 132                 }
 133         }
 134
 135         /**
 136          * Initializes given stacker
 137          *
 138          * @param       $stackerName    Name of the stack
 139          * @param       $forceReInit    Force re-initialization
 140          * @return      void
 141          * @throws      AlreadyInitializedStackerException      If the stack is already initialized
 142          */
 143         public function initStack ($stackerName, $forceReInit = FALSE) {
 144                 // Is the stack already initialized?
 145                 if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
 146                         // Then throw the exception
 147                         throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
 148                 } // END - if
 149
 150                 // Initialize the given stack
 151                 $this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
 152         }
 153
 154         /**
 155          * Checks whether the given stack is initialized (set in array $stackers)
 156          *
 157          * @param       $stackerName    Name of the stack
 158          * @return      $isInitialized  Whether the stack is initialized
 159          */
 160         public function isStackInitialized ($stackerName) {
 161                 // Is is there?
 162                 $this->partialStub('stackerName=' . $stackerName);
 163                 $isInitialized = TRUE;
 164
 165                 // Return result
 166                 return $isInitialized;
 167         }
 168
 169         /**
 170          * Getter for size of given stack (array count)
 171          *
 172          * @param       $stackerName    Name of the stack
 173          * @return      $count                  Size of stack (array count)
 174          * @throws      NoStackerException      If given stack is missing
 175          */
 176         public function getStackCount ($stackerName) {
 177                 // Is the stack not yet initialized?
 178                 if (!$this->isStackInitialized($stackerName)) {
 179                         // Throw an exception
 180                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 181                 } // END - if
 182
 183                 // Now, count the array of entries
 184                 $this->partialStub('stackerName=' . $stackerName);
 185                 $count = 0;
 186
 187                 // Return result
 188                 return $count;
 189         }
 190
 191         /**
 192          * Adds a value to given stack
 193          *
 194          * @param       $stackerName    Name of the stack
 195          * @param       $value                  Value to add to this stacker
 196          * @return      void
 197          * @throws      FullStackerException    Thrown if the stack is full
 198          */
 199         protected function addValue ($stackerName, $value) {
 200                 // Is the stack not yet initialized or full?
 201                 if (!$this->isStackInitialized($stackerName)) {
 202                         // Then do it here
 203                         $this->initStack($stackerName);
 204                 } elseif ($this->isStackFull($stackerName)) {
 205                         // Stacker is full
 206                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 207                 }
 208
 209                 // Now add the value to the stack
 210                 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
 211         }
 212
 213         /**
 214          * Get last value from named stacker
 215          *
 216          * @param       $stackerName    Name of the stack
 217          * @return      $value                  Value of last added value
 218          * @throws      NoStackerException      If the named stacker was not found
 219          * @throws      EmptyStackerException   If the named stacker is empty
 220          */
 221         protected function getLastValue ($stackerName) {
 222                 // Is the stack not yet initialized or full?
 223                 if (!$this->isStackInitialized($stackerName)) {
 224                         // Throw an exception
 225                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 226                 } elseif ($this->isStackEmpty($stackerName)) {
 227                         // Throw an exception
 228                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 229                 }
 230
 231                 // Now get the last value
 232                 $this->partialStub('stackerName=' . $stackerName);
 233                 $value = NULL;
 234
 235                 // Return it
 236                 return $value;
 237         }
 238
 239         /**
 240          * Get first value from named stacker
 241          *
 242          * @param       $stackerName    Name of the stack
 243          * @return      $value                  Value of last added value
 244          * @throws      NoStackerException      If the named stacker was not found
 245          * @throws      EmptyStackerException   If the named stacker is empty
 246          */
 247         protected function getFirstValue ($stackerName) {
 248                 // Is the stack not yet initialized or full?
 249                 if (!$this->isStackInitialized($stackerName)) {
 250                         // Throw an exception
 251                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 252                 } elseif ($this->isStackEmpty($stackerName)) {
 253                         // Throw an exception
 254                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 255                 }
 256
 257                 // Now get the first value
 258                 $this->partialStub('stackerName=' . $stackerName);
 259                 $value = NULL;
 260
 261                 // Return it
 262                 return $value;
 263         }
 264
 265         /**
 266          * "Pops" last entry from stack
 267          *
 268          * @param       $stackerName    Name of the stack
 269          * @return      $value                  Value "poped" from array
 270          * @throws      NoStackerException      If the named stacker was not found
 271          * @throws      EmptyStackerException   If the named stacker is empty
 272          */
 273         protected function popLast ($stackerName) {
 274                 // Is the stack not yet initialized or full?
 275                 if (!$this->isStackInitialized($stackerName)) {
 276                         // Throw an exception
 277                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 278                 } elseif ($this->isStackEmpty($stackerName)) {
 279                         // Throw an exception
 280                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 281                 }
 282
 283                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 284                 $this->partialStub('stackerName=' . $stackerName);
 285                 return NULL;
 286         }
 287
 288         /**
 289          * "Pops" first entry from stack
 290          *
 291          * @param       $stackerName    Name of the stack
 292          * @return      $value                  Value "shifted" from array
 293          * @throws      NoStackerException      If the named stacker was not found
 294          * @throws      EmptyStackerException   If the named stacker is empty
 295          */
 296         protected function popFirst ($stackerName) {
 297                 // Is the stack not yet initialized or full?
 298                 if (!$this->isStackInitialized($stackerName)) {
 299                         // Throw an exception
 300                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 301                 } elseif ($this->isStackEmpty($stackerName)) {
 302                         // Throw an exception
 303                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 304                 }
 305
 306                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 307                 $this->partialStub('stackerName=' . $stackerName);
 308                 return NULL;
 309         }
 310 }
 311
 312 // [EOF]
 313 ?>