No block instance here ...
[core.git] / inc / classes / main / file_directories / io / class_FrameworkFileInputOutputPointer.php
1 <?php
2 /**
3  * A class for reading files
4  *
5  * @author              Roland Haeder <webmaster@shipsimu.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.shipsimu.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 FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputPointer {
25         /**
26          * Protected constructor
27          *
28          * @return      void
29          */
30         protected function __construct () {
31                 // Call parent constructor
32                 parent::__construct(__CLASS__);
33         }
34
35         /**
36          * Create a file pointer based on the given file. The file will also
37          * be verified here.
38          *
39          * @param       $fileName       The file name we shall pass to fopen()
40          * @return      void
41          * @throws      FileIsEmptyException            If the given file name is NULL or empty
42          * @throws      FileReadProtectedException      If PHP cannot read an existing file
43          * @throws      FileWriteProtectedException     If PHP cannot write an existing file
44          * @throws      FileIoException                         If fopen() returns not a file resource
45          */
46         public static final function createFrameworkFileInputOutputPointer ($fileName) {
47                 // Some pre-sanity checks...
48                 if ((is_null($fileName)) || (empty($fileName))) {
49                         // No filename given
50                         throw new FileIsEmptyException(NULL, self::EXCEPTION_UNEXPECTED_EMPTY_STRING);
51                 } elseif ((file_exists($fileName)) && (!is_readable($fileName))) {
52                         // File exists but cannot be read
53                         throw new FileReadProtectedException($fileName, self::EXCEPTION_FILE_CANNOT_BE_READ);
54                 } elseif ((file_exists($fileName)) && (!is_writable($fileName))) {
55                         // File exists but cannot be written
56                         throw new FileWriteProtectedException($fileName, self::EXCEPTION_FILE_CANNOT_BE_READ);
57                 }
58
59                 // Try to open a handler
60                 $filePointer = fopen($fileName, 'c+b');
61                 if ((is_null($filePointer)) || ($filePointer === FALSE)) {
62                         // Something bad happend
63                         throw new FileIoException($fileName, self::EXCEPTION_FILE_POINTER_INVALID);
64                 } // END - if
65
66                 // Create new instance
67                 $pointerInstance = new FrameworkFileInputOutputPointer();
68
69                 // Set file pointer and file name
70                 $pointerInstance->setPointer($filePointer);
71                 $pointerInstance->setFileName($fileName);
72
73                 // Return the instance
74                 return $pointerInstance;
75         }
76
77         /**
78          * Validates file pointer and throws exceptions. This method does not return
79          * anything (not reliable) as this method checks the file pointer and on
80          * case of an error it throws an exception. If this method does not throw
81          * any exceptions, the file pointer seems to be fine.
82          *
83          * @return      void
84          * @throws      NullPointerException    If the file pointer instance
85          *                                                                      is not set by setPointer()
86          * @throws      InvalidResourceException        If there is being set
87          */
88         private function validateFilePointer () {
89                 if (is_null($this->getPointer())) {
90                         // Pointer not initialized
91                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
92                 } elseif (!is_resource($this->getPointer())) {
93                         // Pointer is not a valid resource!
94                         throw new InvalidResourceException($this, self::EXCEPTION_INVALID_RESOURCE);
95                 }
96
97                 // All fine here
98         }
99
100         /**
101          * Read 1024 bytes data from a file pointer
102          *
103          * @return      mixed   The result of fread()
104          */
105         public function readFromFile () {
106                 // Validate the pointer
107                 $this->validateFilePointer();
108
109                 // Read data from the file pointer and return it
110                 return $this->read(1024);
111         }
112
113         /**
114          * Write data to a file pointer
115          *
116          * @param       $dataStream             The data stream we shall write to the file
117          * @return      mixed                   Number of writes bytes or FALSE on error
118          */
119         public function writeToFile ($dataStream) {
120                 // Validate the pointer
121                 $this->validateFilePointer();
122
123                 // Write data to the file pointer and return written bytes
124                 return fwrite($this->getPointer(), $dataStream, strlen($dataStream));
125         }
126
127         /**
128          * Writes at given position by seeking to it.
129          *
130          * @param       $seekPosition   Seek position in file
131          * @param       $data                   Data to be written
132          * @return      mixed                   Number of writes bytes or FALSE on error
133          */
134         public function writeAtPosition ($seekPosition, $data) {
135                 // First seek to it
136                 $this->seek($seekPosition);
137
138                 // Then write the data at that position
139                 return $this->writeToFile($data);
140         }
141
142         /**
143          * Rewinds to the beginning of the file
144          *
145          * @return      $status         Status of this operation
146          */
147         public function rewind () {
148                 // Validate the pointer
149                 $this->validateFilePointer();
150
151                 // Rewind the pointer
152                 return rewind($this->getPointer());
153         }
154
155         /**
156          * Seeks to given position
157          *
158          * @param       $seekPosition   Seek position in file
159          * @param       $whence                 "Seek mode" (see http://de.php.net/fseek)
160          * @return      $status                 Status of this operation
161          */
162         public function seek ($seekPosition, $whence = SEEK_SET) {
163                 // Validate the pointer
164                 $this->validateFilePointer();
165
166                 // Move the file pointer
167                 return fseek($this->getPointer(), $seekPosition, $whence);
168         }
169
170         /**
171          * Reads given amount of bytes from file.
172          *
173          * @param       $bytes  Amount of bytes to read
174          * @return      $data   Data read from file
175          */
176         public function read ($bytes) {
177                 // Validate the pointer
178                 $this->validateFilePointer();
179
180                 // Try to read given characters
181                 $data = fread($this->getPointer(), $bytes);
182
183                 // Was this successfull?
184                 assert(is_string($data));
185
186                 // Then return it
187                 return $data;
188         }
189
190         /**
191          * Analyzes entries in index file. This will count all found (and valid)
192          * entries, mark invalid as damaged and count gaps ("fragmentation"). If
193          * only gaps are found, the file is considered as "virgin" (no entries).
194          *
195          * @return      void
196          * @throws      UnsupportedOperationException   If this method is called
197          */
198         public function analyzeFile () {
199                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
200         }
201
202         /**
203          * Advances to next "block" of bytes
204          *
205          * @return      void
206          * @throws      UnsupportedOperationException   If this method is called
207          */
208         public function next () {
209                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
210         }
211
212         /**
213          * Checks wether the current entry is valid (not at the end of the file).
214          * This method will return TRUE if an emptied (nulled) entry has been found.
215          *
216          * @return      $isValid        Whether the next entry is valid
217          * @throws      UnsupportedOperationException   If this method is called
218          */
219         public function valid () {
220                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
221         }
222
223         /**
224          * Gets current seek position ("key").
225          *
226          * @return      $key    Current key in iteration
227          * @throws      UnsupportedOperationException   If this method is called
228          */
229         public function key () {
230                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
231         }
232
233         /**
234          * "Getter" for file size
235          *
236          * @return      $fileSize       Size of currently loaded file
237          */
238         public function getFileSize () {
239                 // Check if the pointer is still valid
240                 $this->validateFilePointer();
241
242                 // Get file's data
243                 $fileData = fstat($this->getPointer());
244
245                 // Make sure the required array key is there
246                 assert(isset($fileData['size']));
247
248                 // Return size
249                 return $fileData['size'];
250         }
251 }
252
253 // [EOF]
254 ?>