MediaWiki REL1_39
DjVuImage.php
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1<?php
30use Wikimedia\AtEase\AtEase;
31
41class DjVuImage {
42
46 private const DJVUTXT_MEMORY_LIMIT = 300000000;
47
49 private $mFilename;
50
54 public function __construct( $filename ) {
55 $this->mFilename = $filename;
56 }
57
62 public function isValid() {
63 $info = $this->getInfo();
64
65 return $info !== false;
66 }
67
72 public function getImageSize() {
73 $data = $this->getInfo();
74
75 if ( $data !== false ) {
76 return [
77 'width' => $data['width'],
78 'height' => $data['height']
79 ];
80 } else {
81 return [];
82 }
83 }
84
85 // ---------
86
90 public function dump() {
91 $file = fopen( $this->mFilename, 'rb' );
92 $header = fread( $file, 12 );
93 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
94 $chunk = $arr['chunk'];
95 $chunkLength = $arr['chunkLength'];
96 echo "$chunk $chunkLength\n";
97 $this->dumpForm( $file, $chunkLength, 1 );
98 fclose( $file );
99 }
100
101 private function dumpForm( $file, $length, $indent ) {
102 $start = ftell( $file );
103 $secondary = fread( $file, 4 );
104 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
105 while ( ftell( $file ) - $start < $length ) {
106 $chunkHeader = fread( $file, 8 );
107 if ( $chunkHeader == '' ) {
108 break;
109 }
110 $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
111 $chunk = $arr['chunk'];
112 $chunkLength = $arr['chunkLength'];
113 echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
114
115 if ( $chunk == 'FORM' ) {
116 $this->dumpForm( $file, $chunkLength, $indent + 1 );
117 } else {
118 fseek( $file, $chunkLength, SEEK_CUR );
119 if ( $chunkLength & 1 ) {
120 // Padding byte between chunks
121 fseek( $file, 1, SEEK_CUR );
122 }
123 }
124 }
125 }
126
127 private function getInfo() {
128 AtEase::suppressWarnings();
129 $file = fopen( $this->mFilename, 'rb' );
130 AtEase::restoreWarnings();
131 if ( $file === false ) {
132 wfDebug( __METHOD__ . ": missing or failed file read" );
133
134 return false;
135 }
136
137 $header = fread( $file, 16 );
138 $info = false;
139
140 if ( strlen( $header ) < 16 ) {
141 wfDebug( __METHOD__ . ": too short file header" );
142 } else {
143 $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
144
145 $subtype = $arr['subtype'];
146 if ( $arr['magic'] != 'AT&T' ) {
147 wfDebug( __METHOD__ . ": not a DjVu file" );
148 } elseif ( $subtype == 'DJVU' ) {
149 // Single-page document
150 $info = $this->getPageInfo( $file );
151 } elseif ( $subtype == 'DJVM' ) {
152 // Multi-page document
153 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
154 } else {
155 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'" );
156 }
157 }
158 fclose( $file );
159
160 return $info;
161 }
162
163 private function readChunk( $file ) {
164 $header = fread( $file, 8 );
165 if ( strlen( $header ) < 8 ) {
166 return [ false, 0 ];
167 } else {
168 $arr = unpack( 'a4chunk/Nlength', $header );
169
170 return [ $arr['chunk'], $arr['length'] ];
171 }
172 }
173
174 private function skipChunk( $file, $chunkLength ) {
175 fseek( $file, $chunkLength, SEEK_CUR );
176
177 if ( ( $chunkLength & 1 ) && !feof( $file ) ) {
178 // padding byte
179 fseek( $file, 1, SEEK_CUR );
180 }
181 }
182
183 private function getMultiPageInfo( $file, $formLength ) {
184 // For now, we'll just look for the first page in the file
185 // and report its information, hoping others are the same size.
186 $start = ftell( $file );
187 do {
188 list( $chunk, $length ) = $this->readChunk( $file );
189 if ( !$chunk ) {
190 break;
191 }
192
193 if ( $chunk == 'FORM' ) {
194 $subtype = fread( $file, 4 );
195 if ( $subtype == 'DJVU' ) {
196 wfDebug( __METHOD__ . ": found first subpage" );
197
198 return $this->getPageInfo( $file );
199 }
200 $this->skipChunk( $file, $length - 4 );
201 } else {
202 wfDebug( __METHOD__ . ": skipping '$chunk' chunk" );
203 $this->skipChunk( $file, $length );
204 }
205 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
206
207 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages" );
208
209 return false;
210 }
211
212 private function getPageInfo( $file ) {
213 list( $chunk, $length ) = $this->readChunk( $file );
214 if ( $chunk != 'INFO' ) {
215 wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'" );
216
217 return false;
218 }
219
220 if ( $length < 9 ) {
221 wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length" );
222
223 return false;
224 }
225 $data = fread( $file, $length );
226 if ( strlen( $data ) < $length ) {
227 wfDebug( __METHOD__ . ": INFO chunk cut off" );
228
229 return false;
230 }
231
232 $arr = unpack(
233 'nwidth/' .
234 'nheight/' .
235 'Cminor/' .
236 'Cmajor/' .
237 'vresolution/' .
238 'Cgamma', $data );
239
240 # Newer files have rotation info in byte 10, but we don't use it yet.
241
242 return [
243 'width' => $arr['width'],
244 'height' => $arr['height'],
245 'version' => "{$arr['major']}.{$arr['minor']}",
246 'resolution' => $arr['resolution'],
247 'gamma' => $arr['gamma'] / 10.0 ];
248 }
249
254 public function retrieveMetaData() {
255 $djvuDump = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::DjvuDump );
256 $djvuTxt = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::DjvuTxt );
257 if ( !$this->isValid() ) {
258 return false;
259 }
260
261 if ( isset( $djvuDump ) ) {
262 # djvudump is faster than djvutoxml (now abandoned) as of version 3.5
263 # https://sourceforge.net/p/djvu/bugs/71/
264 $cmd = Shell::escape( $djvuDump ) . ' ' . Shell::escape( $this->mFilename );
265 $dump = wfShellExec( $cmd );
266 $json = [ 'data' => $this->convertDumpToJSON( $dump ) ];
267 } else {
268 $json = null;
269 }
270 # Text layer
271 if ( isset( $djvuTxt ) ) {
272 $cmd = Shell::escape( $djvuTxt ) . ' --detail=page ' . Shell::escape( $this->mFilename );
273 wfDebug( __METHOD__ . ": $cmd" );
274 $retval = '';
275 $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
276 $json['text'] = [];
277 if ( $retval == 0 ) {
278 # Strip some control characters
279 # Ignore carriage returns
280 $txt = preg_replace( "/\\\\013/", "", $txt );
281 # Replace runs of OCR region separators with a single extra line break
282 $txt = preg_replace( "/(?:\\\\(035|037))+/", "\n", $txt );
283
284 $reg = <<<EOR
285 /\‍(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
286 ((?> # Text to match is composed of atoms of either:
287 \\\\. # - any escaped character
288 | # - any character different from " and \
289 [^"\\\\]+
290 )*?)
291 "\s*\‍)
292 | # Or page can be empty ; in this case, djvutxt dumps ()
293 \‍(\s*()\)/sx
294EOR;
295 $matches = [];
296 preg_match_all( $reg, $txt, $matches );
297 $json['text'] = array_map( [ $this, 'pageTextCallback' ], $matches[1] );
298 }
299 }
300
301 return $json;
302 }
303
304 private function pageTextCallback( string $match ) {
305 # Get rid of invalid UTF-8
306 $val = UtfNormal\Validator::cleanUp( stripcslashes( $match ) );
307 $val = str_replace( '�', '', $val );
308 return $val;
309 }
310
315 private function convertDumpToJSON( $dump ) {
316 if ( strval( $dump ) == '' ) {
317 return false;
318 }
319
320 $dump = str_replace( "\r", '', $dump );
321 $line = strtok( $dump, "\n" );
322 $m = false;
323 $good = false;
324 $result = [];
325 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
326 # Single-page
327 $parsed = $this->parseFormDjvu( $line );
328 if ( $parsed ) {
329 $good = true;
330 } else {
331 return false;
332 }
333 $result['pages'] = [ $parsed ];
334 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
335 # Multi-page
336 $parentLevel = strlen( $m[1] );
337 # Find DIRM
338 $line = strtok( "\n" );
339 $result['pages'] = [];
340 while ( $line !== false ) {
341 $childLevel = strspn( $line, ' ' );
342 if ( $childLevel <= $parentLevel ) {
343 # End of chunk
344 break;
345 }
346
347 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
348 wfDebug( "Indirect multi-page DjVu document, bad for server!" );
349
350 return false;
351 }
352
353 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
354 # Found page
355 $parsed = $this->parseFormDjvu( $line );
356 if ( $parsed ) {
357 $good = true;
358 } else {
359 return false;
360 }
361 $result['pages'][] = $parsed;
362 }
363 $line = strtok( "\n" );
364 }
365 }
366 if ( !$good ) {
367 return false;
368 }
369
370 return $result;
371 }
372
373 private function parseFormDjvu( $line ) {
374 $parentLevel = strspn( $line, ' ' );
375 $line = strtok( "\n" );
376 # Find INFO
377 while ( $line !== false ) {
378 $childLevel = strspn( $line, ' ' );
379 if ( $childLevel <= $parentLevel ) {
380 # End of chunk
381 break;
382 }
383
384 if ( preg_match(
385 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
386 $line,
387 $m
388 ) ) {
389 return [
390 'height' => (int)$m[2],
391 'width' => (int)$m[1],
392 'dpi' => (float)$m[3],
393 'gamma' => (float)$m[4],
394 ];
395 }
396 $line = strtok( "\n" );
397 }
398
399 # Not found
400 return false;
401 }
402}
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
wfShellExec( $cmd, &$retval=null, $environ=[], $limits=[], $options=[])
Execute a shell command, with time and memory limits mirrored from the PHP configuration if supported...
Support for detecting/validating DjVu image files and getting some basic file metadata (resolution et...
Definition DjVuImage.php:41
retrieveMetaData()
Return an array describing the DjVu image.
dump()
For debugging; dump the IFF chunk structure.
Definition DjVuImage.php:90
isValid()
Check if the given file is indeed a valid DjVu image file.
Definition DjVuImage.php:62
getImageSize()
Return width and height.
Definition DjVuImage.php:72
__construct( $filename)
Definition DjVuImage.php:54
A class containing constants representing the names of configuration variables.
Service locator for MediaWiki core services.
Executes shell commands.
Definition Shell.php:46
$line
Definition mcc.php:119
if(PHP_SAPI !='cli-server') if(!isset( $_SERVER['SCRIPT_FILENAME'])) $file
Item class for a filearchive table row.
Definition router.php:42
$header