inc/classes/main/index/class_BaseIndex.php

   1 <?php
   2 /**
   3  * A general index class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 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 BaseIndex extends BaseFrameworkSystem {
  25         /**
  26          * Magic for this index
  27          */
  28         const INDEX_MAGIC = 'INDEXv0.1';
  29
  30         /**
  31          * Separator for header data
  32          */
  33         const SEPARATOR_HEADER_DATA = 0x01;
  34
  35         /**
  36          * Separator header->entries
  37          */
  38         const SEPARATOR_HEADER_ENTRIES = 0x02;
  39
  40         /**
  41          * Protected constructor
  42          *
  43          * @param       $className      Name of the class
  44          * @return      void
  45          */
  46         protected function __construct ($className) {
  47                 // Call parent constructor
  48                 parent::__construct($className);
  49
  50                 // Calculate header size
  51                 $this->setHeaderSize(
  52                         strlen(self::INDEX_MAGIC) +
  53                         strlen(self::SEPARATOR_HEADER_DATA) +
  54                         self::LENGTH_COUNT +
  55                         strlen(self::SEPARATOR_HEADER_ENTRIES)
  56                 );
  57         }
  58
  59         /**
  60          * Reads the file header
  61          *
  62          * @return      void
  63          */
  64         private function readFileHeader () {
  65                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
  66
  67                 // First rewind to beginning as the header sits at the beginning ...
  68                 $this->getIteratorInstance()->rewind();
  69
  70                 // Then read it (see constructor for calculation)
  71                 $data = $this->getIteratorInstance()->read($this->headerSize);
  72                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->headerSize));
  73
  74                 // Have all requested bytes been read?
  75                 assert(strlen($data) == $this->headerSize);
  76                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  77
  78                 // Last character must be the separator
  79                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
  80                 assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
  81                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  82
  83                 // Okay, then remove it
  84                 $data = substr($data, 0, -1);
  85
  86                 // And update seek position
  87                 $this->updateSeekPosition();
  88
  89                 /*
  90                  * Now split it:
  91                  *
  92                  * 0 => magic
  93                  * 1 => total entries
  94                  */
  95                 $this->header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
  96
  97                 // Check if the array has only 3 elements
  98                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($this->header), print_r($this->header, TRUE)));
  99                 assert(count($this->header) == 2);
 100                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 101
 102                 // Check magic
 103                 assert($this->header[0] == self::INDEX_MAGIC);
 104                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 105
 106                 // Check length of count
 107                 assert(strlen($this->header[1]) == self::LENGTH_COUNT);
 108                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 109
 110                 // Decode count
 111                 $this->header[1] = hex2bin($this->header[1]);
 112
 113                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 114         }
 115
 116         /**
 117          * Checks whether the file header is initialized
 118          *
 119          * @return      $isInitialized  Whether the file header is initialized
 120          */
 121         private function isFileHeaderInitialized () {
 122                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 123                 // Default is not initialized
 124                 $isInitialized = FALSE;
 125
 126                 // Is the file initialized?
 127                 if ($this->isFileInitialized()) {
 128                         // Some bytes has been written, so rewind to start of it.
 129                         $rewindStatus = $this->getIteratorInstance()->rewind();
 130                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
 131
 132                         // Is the rewind() call successfull?
 133                         if ($rewindStatus != 1) {
 134                                 // Something bad happened
 135                                 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Could not rewind().', __METHOD__, __LINE__));
 136                         } // END - if
 137
 138                         // Read file header
 139                         $this->readFileHeader();
 140
 141                         // The above method does already check the header
 142                         $isInitialized = TRUE;
 143                 } // END - if
 144
 145                 // Return result
 146                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 147                 return $isInitialized;
 148         }
 149
 150         /**
 151          * Flushes the file header
 152          *
 153          * @return      void
 154          */
 155         private function flushFileHeader () {
 156                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 157
 158                 // Put all informations together
 159                 $header = sprintf('%s%s',
 160                         // Magic
 161                         self::INDEX_MAGIC,
 162
 163                         // Separator position<->entries
 164                         chr(self::SEPARATOR_HEADER_ENTRIES)
 165                 );
 166
 167                 // Write it to disk (header is always at seek position 0)
 168                 $this->writeData(0, $header);
 169
 170                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 171         }
 172
 173         /**
 174          * Analyzes entries in index file. This will count all found (and valid)
 175          * entries, mark invalid as damaged and count gaps ("fragmentation"). If
 176          * only gaps are found, the file is considered as "virgin" (no entries).
 177          *
 178          * @return      void
 179          */
 180         private function analyzeFile () {
 181                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 182
 183                 // Make sure the file is initialized
 184                 assert($this->isFileInitialized());
 185
 186                 // Init counters and gaps array
 187                 $this->initGapsArray();
 188
 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__));
 191
 192                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 193         }
 194
 195         /**
 196          * Initializes this index
 197          *
 198          * @param       $fileName       File name of this index
 199          * @return      void
 200          */
 201         protected function initIndex ($fileName) {
 202                 // Get a file i/o pointer instance for index file
 203                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 204
 205                 // Get iterator instance
 206                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
 207
 208                 // Is the instance implementing the right interface?
 209                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 210
 211                 // Set iterator here
 212                 $this->setIteratorInstance($iteratorInstance);
 213
 214                 // Is the file's header initialized?
 215                 if (!$this->isFileHeaderInitialized()) {
 216                         // No, then create it (which may pre-allocate the index)
 217                         $this->createFileHeader();
 218
 219                         // And pre-allocate a bit
 220                         $this->preAllocateFile('index');
 221                 } // END - if
 222
 223                 // Load the file header
 224                 $this->readFileHeader();
 225
 226                 // Count all entries in file
 227                 $this->analyzeFile();
 228         }
 229 }
 230
 231 // [EOF]
 232 ?>