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[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 - 2015 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       $fileName       The file name we shall pass to fopen()
40          * @return      void
41          * @throws      FileIsEmptyException            If the given file name is NULL or empty
42          * @throws      FileReadProtectedException      If PHP cannot read an existing file
43          * @throws      FileWriteProtectedException     If PHP cannot write an existing file
44          * @throws      PathWriteProtectedException     If PHP cannot write to an existing path
45          * @throws      FileIoException                         If fopen() returns not a file resource
46          */
47         public static final function createFrameworkFileInputOutputPointer ($fileName) {
48                 // Some pre-sanity checks...
49                 if ((is_null($fileName)) || (empty($fileName))) {
50                         // No filename given
51                         throw new FileIsEmptyException(NULL, self::EXCEPTION_UNEXPECTED_EMPTY_STRING);
52                 } elseif (!BaseFrameworkSystem::isReachableFilePath($fileName)) {
53                         // File exists but cannot be read
54                         throw new FileIoException($fileName, self::EXCEPTION_FILE_NOT_REACHABLE);
55                 } elseif ((!BaseFrameworkSystem::isReadableFile($fileName)) && (file_exists($fileName))) {
56                         // File exists but cannot be read
57                         throw new FileReadProtectedException($fileName, self::EXCEPTION_FILE_CANNOT_BE_READ);
58                 } elseif ((file_exists($fileName)) && (!is_writable($fileName))) {
59                         // File exists but cannot be written
60                         throw new FileWriteProtectedException($fileName, self::EXCEPTION_FILE_CANNOT_BE_WRITTEN);
61                 } elseif (!is_writable(dirname($fileName))) {
62                         // Path is not writable
63                         throw new PathWriteProtectedException($fileName, self::EXCEPTION_PATH_CANNOT_BE_WRITTEN);
64                 }
65
66                 // Try to open a handler
67                 $filePointer = fopen($fileName, 'c+b');
68                 if ((is_null($filePointer)) || ($filePointer === FALSE)) {
69                         // Something bad happend
70                         throw new FileIoException($fileName, self::EXCEPTION_FILE_POINTER_INVALID);
71                 } // END - if
72
73                 // Create new instance
74                 $pointerInstance = new FrameworkFileInputOutputPointer();
75
76                 // Set file pointer and file name
77                 $pointerInstance->setPointer($filePointer);
78                 $pointerInstance->setFileName($fileName);
79
80                 // Return the instance
81                 return $pointerInstance;
82         }
83
84         /**
85          * Validates file pointer and throws exceptions. This method does not return
86          * anything (not reliable) as this method checks the file pointer and on
87          * case of an error it throws an exception. If this method does not throw
88          * any exceptions, the file pointer seems to be fine.
89          *
90          * @return      void
91          * @throws      NullPointerException    If the file pointer instance
92          *                                                                      is not set by setPointer()
93          * @throws      InvalidResourceException        If there is being set
94          */
95         private function validateFilePointer () {
96                 if (is_null($this->getPointer())) {
97                         // Pointer not initialized
98                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
99                 } elseif (!is_resource($this->getPointer())) {
100                         // Pointer is not a valid resource!
101                         throw new InvalidResourceException($this, self::EXCEPTION_INVALID_RESOURCE);
102                 }
103
104                 // All fine here
105         }
106
107         /**
108          * Read 1024 bytes data from a file pointer
109          *
110          * @return      mixed   The result of fread()
111          */
112         public function readFromFile () {
113                 // Validate the pointer
114                 $this->validateFilePointer();
115
116                 // Read data from the file pointer and return it
117                 return $this->read(1024);
118         }
119
120         /**
121          * Write data to a file pointer
122          *
123          * @param       $dataStream             The data stream we shall write to the file
124          * @return      mixed                   Number of writes bytes or FALSE on error
125          */
126         public function writeToFile ($dataStream) {
127                 // Validate the pointer
128                 $this->validateFilePointer();
129
130                 // Write data to the file pointer and return written bytes
131                 return fwrite($this->getPointer(), $dataStream, strlen($dataStream));
132         }
133
134         /**
135          * Writes at given position by seeking to it.
136          *
137          * @param       $seekPosition   Seek position in file
138          * @param       $data                   Data to be written
139          * @return      mixed                   Number of writes bytes or FALSE on error
140          */
141         public function writeAtPosition ($seekPosition, $data) {
142                 // First seek to it
143                 $this->seek($seekPosition);
144
145                 // Then write the data at that position
146                 return $this->writeToFile($data);
147         }
148
149         /**
150          * Rewinds to the beginning of the file
151          *
152          * @return      $status         Status of this operation
153          */
154         public function rewind () {
155                 // Validate the pointer
156                 $this->validateFilePointer();
157
158                 // Rewind the pointer
159                 return rewind($this->getPointer());
160         }
161
162         /**
163          * Seeks to given position
164          *
165          * @param       $seekPosition   Seek position in file
166          * @param       $whence                 "Seek mode" (see http://de.php.net/fseek)
167          * @return      $status                 Status of this operation
168          */
169         public function seek ($seekPosition, $whence = SEEK_SET) {
170                 // Validate the pointer
171                 $this->validateFilePointer();
172
173                 // Move the file pointer
174                 return fseek($this->getPointer(), $seekPosition, $whence);
175         }
176
177         /**
178          * Reads a line, maximum 4096 Bytes from current file pointer
179          *
180          * @return      $data   Read data from file
181          */
182         public function readLine () {
183                 // Read whole line
184                 return $this->read();
185         }
186
187         /**
188          * Reads given amount of bytes from file.
189          *
190          * @param       $bytes  Amount of bytes to read
191          * @return      $data   Data read from file
192          */
193         public function read ($bytes = NULL) {
194                 // Validate the pointer
195                 $this->validateFilePointer();
196
197                 // Is $bytes set?
198                 if (is_int($bytes)) {
199                         // Try to read given characters
200                         $data = fread($this->getPointer(), $bytes);
201                 } else {
202                         // Try to read whole line
203                         $data = fread($this->getPointer());
204                 }
205
206                 // Then return it
207                 return $data;
208         }
209
210         /**
211          * Analyzes entries in index file. This will count all found (and valid)
212          * entries, mark invalid as damaged and count gaps ("fragmentation"). If
213          * only gaps are found, the file is considered as "virgin" (no entries).
214          *
215          * @return      void
216          * @throws      UnsupportedOperationException   If this method is called
217          */
218         public function analyzeFile () {
219                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
220         }
221
222         /**
223          * Advances to next "block" of bytes
224          *
225          * @return      void
226          * @throws      UnsupportedOperationException   If this method is called
227          */
228         public function next () {
229                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
230         }
231
232         /**
233          * Checks wether the current entry is valid (not at the end of the file).
234          * This method will return TRUE if an emptied (nulled) entry has been found.
235          *
236          * @return      $isValid        Whether the next entry is valid
237          * @throws      UnsupportedOperationException   If this method is called
238          */
239         public function valid () {
240                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
241         }
242
243         /**
244          * Gets current seek position ("key").
245          *
246          * @return      $key    Current key in iteration
247          * @throws      UnsupportedOperationException   If this method is called
248          */
249         public function key () {
250                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
251         }
252
253         /**
254          * "Getter" for file size
255          *
256          * @return      $fileSize       Size of currently loaded file
257          */
258         public function getFileSize () {
259                 // Check if the pointer is still valid
260                 $this->validateFilePointer();
261
262                 // Get file's data
263                 $fileData = fstat($this->getPointer());
264
265                 // Make sure the required array key is there
266                 assert(isset($fileData['size']));
267
268                 // Return size
269                 return $fileData['size'];
270         }
271 }
272
273 // [EOF]
274 ?>