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          * Constructor
  44          *
  45          * @param string $filename The DjVu file name.
  46          */
  47         function __construct( $filename ) {
  48                 $this->mFilename = $filename;
  49         }
  50
  51         /**
  52          * Check if the given file is indeed a valid DjVu image file
  53          * @return bool
  54          */
  55         public function isValid() {
  56                 $info = $this->getInfo();
  57
  58                 return $info !== false;
  59         }
  60
  61         /**
  62          * Return data in the style of getimagesize()
  63          * @return array|bool Array or false on failure
  64          */
  65         public function getImageSize() {
  66                 $data = $this->getInfo();
  67
  68                 if ( $data !== false ) {
  69                         $width = $data['width'];
  70                         $height = $data['height'];
  71
  72                         return [ $width, $height, 'DjVu',
  73                                 "width=\"$width\" height=\"$height\"" ];
  74                 }
  75
  76                 return false;
  77         }
  78
  79         // ---------
  80
  81         /**
  82          * For debugging; dump the IFF chunk structure
  83          */
  84         function dump() {
  85                 $file = fopen( $this->mFilename, 'rb' );
  86                 $header = fread( $file, 12 );
  87                 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
  88                 $chunk = $arr['chunk'];
  89                 $chunkLength = $arr['chunkLength'];
  90                 echo "$chunk $chunkLength\n";
  91                 $this->dumpForm( $file, $chunkLength, 1 );
  92                 fclose( $file );
  93         }
  94
  95         private function dumpForm( $file, $length, $indent ) {
  96                 $start = ftell( $file );
  97                 $secondary = fread( $file, 4 );
  98                 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
  99                 while ( ftell( $file ) - $start < $length ) {
 100                         $chunkHeader = fread( $file, 8 );
 101                         if ( $chunkHeader == '' ) {
 102                                 break;
 103                         }
 104                         $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
 105                         $chunk = $arr['chunk'];
 106                         $chunkLength = $arr['chunkLength'];
 107                         echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
 108
 109                         if ( $chunk == 'FORM' ) {
 110                                 $this->dumpForm( $file, $chunkLength, $indent + 1 );
 111                         } else {
 112                                 fseek( $file, $chunkLength, SEEK_CUR );
 113                                 if ( $chunkLength & 1 == 1 ) {
 114                                         // Padding byte between chunks
 115                                         fseek( $file, 1, SEEK_CUR );
 116                                 }
 117                         }
 118                 }
 119         }
 120
 121         function getInfo() {
 122                 MediaWiki\suppressWarnings();
 123                 $file = fopen( $this->mFilename, 'rb' );
 124                 MediaWiki\restoreWarnings();
 125                 if ( $file === false ) {
 126                         wfDebug( __METHOD__ . ": missing or failed file read\n" );
 127
 128                         return false;
 129                 }
 130
 131                 $header = fread( $file, 16 );
 132                 $info = false;
 133
 134                 if ( strlen( $header ) < 16 ) {
 135                         wfDebug( __METHOD__ . ": too short file header\n" );
 136                 } else {
 137                         $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
 138
 139                         $subtype = $arr['subtype'];
 140                         if ( $arr['magic'] != 'AT&T' ) {
 141                                 wfDebug( __METHOD__ . ": not a DjVu file\n" );
 142                         } elseif ( $subtype == 'DJVU' ) {
 143                                 // Single-page document
 144                                 $info = $this->getPageInfo( $file );
 145                         } elseif ( $subtype == 'DJVM' ) {
 146                                 // Multi-page document
 147                                 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
 148                         } else {
 149                                 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
 150                         }
 151                 }
 152                 fclose( $file );
 153
 154                 return $info;
 155         }
 156
 157         private function readChunk( $file ) {
 158                 $header = fread( $file, 8 );
 159                 if ( strlen( $header ) < 8 ) {
 160                         return [ false, 0 ];
 161                 } else {
 162                         $arr = unpack( 'a4chunk/Nlength', $header );
 163
 164                         return [ $arr['chunk'], $arr['length'] ];
 165                 }
 166         }
 167
 168         private function skipChunk( $file, $chunkLength ) {
 169                 fseek( $file, $chunkLength, SEEK_CUR );
 170
 171                 if ( $chunkLength & 0x01 == 1 && !feof( $file ) ) {
 172                         // padding byte
 173                         fseek( $file, 1, SEEK_CUR );
 174                 }
 175         }
 176
 177         private function getMultiPageInfo( $file, $formLength ) {
 178                 // For now, we'll just look for the first page in the file
 179                 // and report its information, hoping others are the same size.
 180                 $start = ftell( $file );
 181                 do {
 182                         list( $chunk, $length ) = $this->readChunk( $file );
 183                         if ( !$chunk ) {
 184                                 break;
 185                         }
 186
 187                         if ( $chunk == 'FORM' ) {
 188                                 $subtype = fread( $file, 4 );
 189                                 if ( $subtype == 'DJVU' ) {
 190                                         wfDebug( __METHOD__ . ": found first subpage\n" );
 191
 192                                         return $this->getPageInfo( $file );
 193                                 }
 194                                 $this->skipChunk( $file, $length - 4 );
 195                         } else {
 196                                 wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
 197                                 $this->skipChunk( $file, $length );
 198                         }
 199                 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
 200
 201                 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
 202
 203                 return false;
 204         }
 205
 206         private function getPageInfo( $file ) {
 207                 list( $chunk, $length ) = $this->readChunk( $file );
 208                 if ( $chunk != 'INFO' ) {
 209                         wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
 210
 211                         return false;
 212                 }
 213
 214                 if ( $length < 9 ) {
 215                         wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
 216
 217                         return false;
 218                 }
 219                 $data = fread( $file, $length );
 220                 if ( strlen( $data ) < $length ) {
 221                         wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
 222
 223                         return false;
 224                 }
 225
 226                 $arr = unpack(
 227                         'nwidth/' .
 228                         'nheight/' .
 229                         'Cminor/' .
 230                         'Cmajor/' .
 231                         'vresolution/' .
 232                         'Cgamma', $data );
 233
 234                 # Newer files have rotation info in byte 10, but we don't use it yet.
 235
 236                 return [
 237                         'width' => $arr['width'],
 238                         'height' => $arr['height'],
 239                         'version' => "{$arr['major']}.{$arr['minor']}",
 240                         'resolution' => $arr['resolution'],
 241                         'gamma' => $arr['gamma'] / 10.0 ];
 242         }
 243
 244         /**
 245          * Return an XML string describing the DjVu image
 246          * @return string|bool
 247          */
 248         function retrieveMetaData() {
 249                 global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
 250
 251                 if ( !$this->isValid() ) {
 252                         return false;
 253                 }
 254
 255                 if ( isset( $wgDjvuDump ) ) {
 256                         # djvudump is faster as of version 3.5
 257                         # https://sourceforge.net/p/djvu/bugs/71/
 258                         $cmd = wfEscapeShellArg( $wgDjvuDump ) . ' ' . wfEscapeShellArg( $this->mFilename );
 259                         $dump = wfShellExec( $cmd );
 260                         $xml = $this->convertDumpToXML( $dump );
 261                 } elseif ( isset( $wgDjvuToXML ) ) {
 262                         $cmd = wfEscapeShellArg( $wgDjvuToXML ) . ' --without-anno --without-text ' .
 263                                 wfEscapeShellArg( $this->mFilename );
 264                         $xml = wfShellExec( $cmd );
 265                 } else {
 266                         $xml = null;
 267                 }
 268                 # Text layer
 269                 if ( isset( $wgDjvuTxt ) ) {
 270                         $cmd = wfEscapeShellArg( $wgDjvuTxt ) . ' --detail=page ' . wfEscapeShellArg( $this->mFilename );
 271                         wfDebug( __METHOD__ . ": $cmd\n" );
 272                         $retval = '';
 273                         $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
 274                         if ( $retval == 0 ) {
 275                                 # Strip some control characters
 276                                 $txt = preg_replace( "/[\013\035\037]/", "", $txt );
 277                                 $reg = <<<EOR
 278                                         /\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
 279                                         ((?>    # Text to match is composed of atoms of either:
 280                                           \\\\. # - any escaped character
 281                                           |     # - any character different from " and \
 282                                           [^"\\\\]+
 283                                         )*?)
 284                                         "\s*\)
 285                                         | # Or page can be empty ; in this case, djvutxt dumps ()
 286                                         \(\s*()\)/sx
 287 EOR;
 288                                 $txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
 289                                 $txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
 290                                 $xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 );
 291                                 $xml = $xml . $txt . '</mw-djvu>';
 292                         }
 293                 }
 294
 295                 return $xml;
 296         }
 297
 298         function pageTextCallback( $matches ) {
 299                 # Get rid of invalid UTF-8, strip control characters
 300                 $val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
 301                 $val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
 302                 return '<PAGE value="' . $val . '" />';
 303         }
 304
 305         /**
 306          * Hack to temporarily work around djvutoxml bug
 307          * @param string $dump
 308          * @return string
 309          */
 310         function convertDumpToXML( $dump ) {
 311                 if ( strval( $dump ) == '' ) {
 312                         return false;
 313                 }
 314
 315                 $xml = <<<EOT
 316 <?xml version="1.0" ?>
 317 <!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
 318 <DjVuXML>
 319 <HEAD></HEAD>
 320 <BODY>
 321 EOT;
 322
 323                 $dump = str_replace( "\r", '', $dump );
 324                 $line = strtok( $dump, "\n" );
 325                 $m = false;
 326                 $good = false;
 327                 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
 328                         # Single-page
 329                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 330                                 $good = true;
 331                         } else {
 332                                 return false;
 333                         }
 334                 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
 335                         # Multi-page
 336                         $parentLevel = strlen( $m[1] );
 337                         # Find DIRM
 338                         $line = strtok( "\n" );
 339                         while ( $line !== false ) {
 340                                 $childLevel = strspn( $line, ' ' );
 341                                 if ( $childLevel <= $parentLevel ) {
 342                                         # End of chunk
 343                                         break;
 344                                 }
 345
 346                                 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
 347                                         wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
 348
 349                                         return false;
 350                                 }
 351                                 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
 352                                         # Found page
 353                                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 354                                                 $good = true;
 355                                         } else {
 356                                                 return false;
 357                                         }
 358                                 }
 359                                 $line = strtok( "\n" );
 360                         }
 361                 }
 362                 if ( !$good ) {
 363                         return false;
 364                 }
 365
 366                 $xml .= "</BODY>\n</DjVuXML>\n";
 367
 368                 return $xml;
 369         }
 370
 371         function parseFormDjvu( $line, &$xml ) {
 372                 $parentLevel = strspn( $line, ' ' );
 373                 $line = strtok( "\n" );
 374
 375                 # Find INFO
 376                 while ( $line !== false ) {
 377                         $childLevel = strspn( $line, ' ' );
 378                         if ( $childLevel <= $parentLevel ) {
 379                                 # End of chunk
 380                                 break;
 381                         }
 382
 383                         if ( preg_match(
 384                                 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
 385                                 $line,
 386                                 $m
 387                         ) ) {
 388                                 $xml .= Xml::tags(
 389                                         'OBJECT',
 390                                         [
 391                                                 # 'data' => '',
 392                                                 # 'type' => 'image/x.djvu',
 393                                                 'height' => $m[2],
 394                                                 'width' => $m[1],
 395                                                 # 'usemap' => '',
 396                                         ],
 397                                         "\n" .
 398                                                 Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
 399                                                 Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
 400                                 ) . "\n";
 401
 402                                 return true;
 403                         }
 404                         $line = strtok( "\n" );
 405                 }
 406
 407                 # Not found
 408                 return false;
 409         }
 410 }