includes/media/DjVuImage.php

   1 <?php
   2 /**
   3  * DjVu image handler.
   4  *
   5  * Copyright © 2006 Brion Vibber <brion@pobox.com>
   6  * https://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup Media
  25  */
  26
  27 /**
  28  * Support for detecting/validating DjVu image files and getting
  29  * some basic file metadata (resolution etc)
  30  *
  31  * File format docs are available in source package for DjVuLibre:
  32  * http://djvulibre.djvuzone.org/
  33  *
  34  * @ingroup Media
  35  */
  36 class DjVuImage {
  37         /**
  38          * @const DJVUTXT_MEMORY_LIMIT Memory limit for the DjVu description software
  39          */
  40         const DJVUTXT_MEMORY_LIMIT = 300000;
  41
  42         /**
  43          * @param string $filename The DjVu file name.
  44          */
  45         function __construct( $filename ) {
  46                 $this->mFilename = $filename;
  47         }
  48
  49         /**
  50          * Check if the given file is indeed a valid DjVu image file
  51          * @return bool
  52          */
  53         public function isValid() {
  54                 $info = $this->getInfo();
  55
  56                 return $info !== false;
  57         }
  58
  59         /**
  60          * Return data in the style of getimagesize()
  61          * @return array|bool Array or false on failure
  62          */
  63         public function getImageSize() {
  64                 $data = $this->getInfo();
  65
  66                 if ( $data !== false ) {
  67                         $width = $data['width'];
  68                         $height = $data['height'];
  69
  70                         return [ $width, $height, 'DjVu',
  71                                 "width=\"$width\" height=\"$height\"" ];
  72                 }
  73
  74                 return false;
  75         }
  76
  77         // ---------
  78
  79         /**
  80          * For debugging; dump the IFF chunk structure
  81          */
  82         function dump() {
  83                 $file = fopen( $this->mFilename, 'rb' );
  84                 $header = fread( $file, 12 );
  85                 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
  86                 $chunk = $arr['chunk'];
  87                 $chunkLength = $arr['chunkLength'];
  88                 echo "$chunk $chunkLength\n";
  89                 $this->dumpForm( $file, $chunkLength, 1 );
  90                 fclose( $file );
  91         }
  92
  93         private function dumpForm( $file, $length, $indent ) {
  94                 $start = ftell( $file );
  95                 $secondary = fread( $file, 4 );
  96                 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
  97                 while ( ftell( $file ) - $start < $length ) {
  98                         $chunkHeader = fread( $file, 8 );
  99                         if ( $chunkHeader == '' ) {
 100                                 break;
 101                         }
 102                         $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
 103                         $chunk = $arr['chunk'];
 104                         $chunkLength = $arr['chunkLength'];
 105                         echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
 106
 107                         if ( $chunk == 'FORM' ) {
 108                                 $this->dumpForm( $file, $chunkLength, $indent + 1 );
 109                         } else {
 110                                 fseek( $file, $chunkLength, SEEK_CUR );
 111                                 if ( $chunkLength & 1 == 1 ) {
 112                                         // Padding byte between chunks
 113                                         fseek( $file, 1, SEEK_CUR );
 114                                 }
 115                         }
 116                 }
 117         }
 118
 119         function getInfo() {
 120                 MediaWiki\suppressWarnings();
 121                 $file = fopen( $this->mFilename, 'rb' );
 122                 MediaWiki\restoreWarnings();
 123                 if ( $file === false ) {
 124                         wfDebug( __METHOD__ . ": missing or failed file read\n" );
 125
 126                         return false;
 127                 }
 128
 129                 $header = fread( $file, 16 );
 130                 $info = false;
 131
 132                 if ( strlen( $header ) < 16 ) {
 133                         wfDebug( __METHOD__ . ": too short file header\n" );
 134                 } else {
 135                         $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
 136
 137                         $subtype = $arr['subtype'];
 138                         if ( $arr['magic'] != 'AT&T' ) {
 139                                 wfDebug( __METHOD__ . ": not a DjVu file\n" );
 140                         } elseif ( $subtype == 'DJVU' ) {
 141                                 // Single-page document
 142                                 $info = $this->getPageInfo( $file );
 143                         } elseif ( $subtype == 'DJVM' ) {
 144                                 // Multi-page document
 145                                 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
 146                         } else {
 147                                 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
 148                         }
 149                 }
 150                 fclose( $file );
 151
 152                 return $info;
 153         }
 154
 155         private function readChunk( $file ) {
 156                 $header = fread( $file, 8 );
 157                 if ( strlen( $header ) < 8 ) {
 158                         return [ false, 0 ];
 159                 } else {
 160                         $arr = unpack( 'a4chunk/Nlength', $header );
 161
 162                         return [ $arr['chunk'], $arr['length'] ];
 163                 }
 164         }
 165
 166         private function skipChunk( $file, $chunkLength ) {
 167                 fseek( $file, $chunkLength, SEEK_CUR );
 168
 169                 if ( $chunkLength & 0x01 == 1 && !feof( $file ) ) {
 170                         // padding byte
 171                         fseek( $file, 1, SEEK_CUR );
 172                 }
 173         }
 174
 175         private function getMultiPageInfo( $file, $formLength ) {
 176                 // For now, we'll just look for the first page in the file
 177                 // and report its information, hoping others are the same size.
 178                 $start = ftell( $file );
 179                 do {
 180                         list( $chunk, $length ) = $this->readChunk( $file );
 181                         if ( !$chunk ) {
 182                                 break;
 183                         }
 184
 185                         if ( $chunk == 'FORM' ) {
 186                                 $subtype = fread( $file, 4 );
 187                                 if ( $subtype == 'DJVU' ) {
 188                                         wfDebug( __METHOD__ . ": found first subpage\n" );
 189
 190                                         return $this->getPageInfo( $file );
 191                                 }
 192                                 $this->skipChunk( $file, $length - 4 );
 193                         } else {
 194                                 wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
 195                                 $this->skipChunk( $file, $length );
 196                         }
 197                 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
 198
 199                 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
 200
 201                 return false;
 202         }
 203
 204         private function getPageInfo( $file ) {
 205                 list( $chunk, $length ) = $this->readChunk( $file );
 206                 if ( $chunk != 'INFO' ) {
 207                         wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
 208
 209                         return false;
 210                 }
 211
 212                 if ( $length < 9 ) {
 213                         wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
 214
 215                         return false;
 216                 }
 217                 $data = fread( $file, $length );
 218                 if ( strlen( $data ) < $length ) {
 219                         wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
 220
 221                         return false;
 222                 }
 223
 224                 $arr = unpack(
 225                         'nwidth/' .
 226                         'nheight/' .
 227                         'Cminor/' .
 228                         'Cmajor/' .
 229                         'vresolution/' .
 230                         'Cgamma', $data );
 231
 232                 # Newer files have rotation info in byte 10, but we don't use it yet.
 233
 234                 return [
 235                         'width' => $arr['width'],
 236                         'height' => $arr['height'],
 237                         'version' => "{$arr['major']}.{$arr['minor']}",
 238                         'resolution' => $arr['resolution'],
 239                         'gamma' => $arr['gamma'] / 10.0 ];
 240         }
 241
 242         /**
 243          * Return an XML string describing the DjVu image
 244          * @return string|bool
 245          */
 246         function retrieveMetaData() {
 247                 global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
 248
 249                 if ( !$this->isValid() ) {
 250                         return false;
 251                 }
 252
 253                 if ( isset( $wgDjvuDump ) ) {
 254                         # djvudump is faster as of version 3.5
 255                         # https://sourceforge.net/p/djvu/bugs/71/
 256                         $cmd = wfEscapeShellArg( $wgDjvuDump ) . ' ' . wfEscapeShellArg( $this->mFilename );
 257                         $dump = wfShellExec( $cmd );
 258                         $xml = $this->convertDumpToXML( $dump );
 259                 } elseif ( isset( $wgDjvuToXML ) ) {
 260                         $cmd = wfEscapeShellArg( $wgDjvuToXML ) . ' --without-anno --without-text ' .
 261                                 wfEscapeShellArg( $this->mFilename );
 262                         $xml = wfShellExec( $cmd );
 263                 } else {
 264                         $xml = null;
 265                 }
 266                 # Text layer
 267                 if ( isset( $wgDjvuTxt ) ) {
 268                         $cmd = wfEscapeShellArg( $wgDjvuTxt ) . ' --detail=page ' . wfEscapeShellArg( $this->mFilename );
 269                         wfDebug( __METHOD__ . ": $cmd\n" );
 270                         $retval = '';
 271                         $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
 272                         if ( $retval == 0 ) {
 273                                 # Strip some control characters
 274                                 $txt = preg_replace( "/[\013\035\037]/", "", $txt );
 275                                 $reg = <<<EOR
 276                                         /\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
 277                                         ((?>    # Text to match is composed of atoms of either:
 278                                                 \\\\. # - any escaped character
 279                                                 |     # - any character different from " and \
 280                                                 [^"\\\\]+
 281                                         )*?)
 282                                         "\s*\)
 283                                         | # Or page can be empty ; in this case, djvutxt dumps ()
 284                                         \(\s*()\)/sx
 285 EOR;
 286                                 $txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
 287                                 $txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
 288                                 $xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 );
 289                                 $xml = $xml . $txt . '</mw-djvu>';
 290                         }
 291                 }
 292
 293                 return $xml;
 294         }
 295
 296         function pageTextCallback( $matches ) {
 297                 # Get rid of invalid UTF-8, strip control characters
 298                 $val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
 299                 $val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
 300                 return '<PAGE value="' . $val . '" />';
 301         }
 302
 303         /**
 304          * Hack to temporarily work around djvutoxml bug
 305          * @param string $dump
 306          * @return string
 307          */
 308         function convertDumpToXML( $dump ) {
 309                 if ( strval( $dump ) == '' ) {
 310                         return false;
 311                 }
 312
 313                 $xml = <<<EOT
 314 <?xml version="1.0" ?>
 315 <!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
 316 <DjVuXML>
 317 <HEAD></HEAD>
 318 <BODY>
 319 EOT;
 320
 321                 $dump = str_replace( "\r", '', $dump );
 322                 $line = strtok( $dump, "\n" );
 323                 $m = false;
 324                 $good = false;
 325                 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
 326                         # Single-page
 327                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 328                                 $good = true;
 329                         } else {
 330                                 return false;
 331                         }
 332                 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
 333                         # Multi-page
 334                         $parentLevel = strlen( $m[1] );
 335                         # Find DIRM
 336                         $line = strtok( "\n" );
 337                         while ( $line !== false ) {
 338                                 $childLevel = strspn( $line, ' ' );
 339                                 if ( $childLevel <= $parentLevel ) {
 340                                         # End of chunk
 341                                         break;
 342                                 }
 343
 344                                 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
 345                                         wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
 346
 347                                         return false;
 348                                 }
 349                                 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
 350                                         # Found page
 351                                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 352                                                 $good = true;
 353                                         } else {
 354                                                 return false;
 355                                         }
 356                                 }
 357                                 $line = strtok( "\n" );
 358                         }
 359                 }
 360                 if ( !$good ) {
 361                         return false;
 362                 }
 363
 364                 $xml .= "</BODY>\n</DjVuXML>\n";
 365
 366                 return $xml;
 367         }
 368
 369         function parseFormDjvu( $line, &$xml ) {
 370                 $parentLevel = strspn( $line, ' ' );
 371                 $line = strtok( "\n" );
 372
 373                 # Find INFO
 374                 while ( $line !== false ) {
 375                         $childLevel = strspn( $line, ' ' );
 376                         if ( $childLevel <= $parentLevel ) {
 377                                 # End of chunk
 378                                 break;
 379                         }
 380
 381                         if ( preg_match(
 382                                 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
 383                                 $line,
 384                                 $m
 385                         ) ) {
 386                                 $xml .= Xml::tags(
 387                                         'OBJECT',
 388                                         [
 389                                                 # 'data' => '',
 390                                                 # 'type' => 'image/x.djvu',
 391                                                 'height' => $m[2],
 392                                                 'width' => $m[1],
 393                                                 # 'usemap' => '',
 394                                         ],
 395                                         "\n" .
 396                                                 Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
 397                                                 Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
 398                                 ) . "\n";
 399
 400                                 return true;
 401                         }
 402                         $line = strtok( "\n" );
 403                 }
 404
 405                 # Not found
 406                 return false;
 407         }
 408 }