includes/Exif.php

   1 <?php
   2 /**
   3  * Exif metadata reader
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @ingroup Media
  21  * @author Ævar Arnfjörð Bjarmason <avarab@gmail.com>
  22  * @copyright Copyright © 2005, Ævar Arnfjörð Bjarmason
  23  * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
  24  * @see http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  25  * @file
  26  */
  27
  28 /**
  29  * @todo document (e.g. one-sentence class-overview description)
  30  * @ingroup Media
  31  */
  32 class Exif {
  33
  34         const BYTE      = 1;    //!< An 8-bit (1-byte) unsigned integer.
  35         const ASCII     = 2;    //!< An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
  36         const SHORT     = 3;    //!< A 16-bit (2-byte) unsigned integer.
  37         const LONG      = 4;    //!< A 32-bit (4-byte) unsigned integer.
  38         const RATIONAL  = 5;    //!< Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
  39         const UNDEFINED = 7;    //!< An 8-bit byte that can take any value depending on the field definition
  40         const SLONG     = 9;    //!< A 32-bit (4-byte) signed integer (2's complement notation),
  41         const SRATIONAL = 10;   //!< Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.
  42
  43         //@{
  44         /* @var array
  45          * @private
  46          */
  47
  48         /**
  49          * Exif tags grouped by category, the tagname itself is the key and the type
  50          * is the value, in the case of more than one possible value type they are
  51          * separated by commas.
  52          */
  53         var $mExifTags;
  54
  55         /**
  56          * A one dimentional array of all Exif tags
  57          */
  58         var $mFlatExifTags;
  59
  60         /**
  61          * The raw Exif data returned by exif_read_data()
  62          */
  63         var $mRawExifData;
  64
  65         /**
  66          * A Filtered version of $mRawExifData that has been pruned of invalid
  67          * tags and tags that contain content they shouldn't contain according
  68          * to the Exif specification
  69          */
  70         var $mFilteredExifData;
  71
  72         /**
  73          * Filtered and formatted Exif data, see FormatExif::getFormattedData()
  74          */
  75         var $mFormattedExifData;
  76
  77         //@}
  78
  79         //@{
  80         /* @var string
  81          * @private
  82          */
  83
  84         /**
  85          * The file being processed
  86          */
  87         var $file;
  88
  89         /**
  90          * The basename of the file being processed
  91          */
  92         var $basename;
  93
  94         /**
  95          * The private log to log to, e.g. 'exif'
  96          */
  97         var $log = false;
  98
  99         //@}
 100
 101         /**
 102          * Constructor
 103          *
 104          * @param $file String: filename.
 105          */
 106         function __construct( $file ) {
 107                 /**
 108                  * Page numbers here refer to pages in the EXIF 2.2 standard
 109                  *
 110                  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
 111                  */
 112                 $this->mExifTags = array(
 113                         # TIFF Rev. 6.0 Attribute Information (p22)
 114                         'tiff' => array(
 115                                 # Tags relating to image structure
 116                                 'structure' => array(
 117                                         'ImageWidth' => Exif::SHORT.','.Exif::LONG,             # Image width
 118                                         'ImageLength' => Exif::SHORT.','.Exif::LONG,    # Image height
 119                                         'BitsPerSample' => Exif::SHORT,                 # Number of bits per component
 120                                         # "When a primary image is JPEG compressed, this designation is not"
 121                                         # "necessary and is omitted." (p23)
 122                                         'Compression' => Exif::SHORT,                           # Compression scheme #p23
 123                                         'PhotometricInterpretation' => Exif::SHORT,             # Pixel composition #p23
 124                                         'Orientation' => Exif::SHORT,                           # Orientation of image #p24
 125                                         'SamplesPerPixel' => Exif::SHORT,                       # Number of components
 126                                         'PlanarConfiguration' => Exif::SHORT,                   # Image data arrangement #p24
 127                                         'YCbCrSubSampling' => Exif::SHORT,                      # Subsampling ratio of Y to C #p24
 128                                         'YCbCrPositioning' => Exif::SHORT,                      # Y and C positioning #p24-25
 129                                         'XResolution' => Exif::RATIONAL,                        # Image resolution in width direction
 130                                         'YResolution' => Exif::RATIONAL,                        # Image resolution in height direction
 131                                         'ResolutionUnit' => Exif::SHORT,                        # Unit of X and Y resolution #(p26)
 132                                 ),
 133
 134                                 # Tags relating to recording offset
 135                                 'offset' => array(
 136                                         'StripOffsets' => Exif::SHORT.','.Exif::LONG,                   # Image data location
 137                                         'RowsPerStrip' => Exif::SHORT.','.Exif::LONG,                   # Number of rows per strip
 138                                         'StripByteCounts' => Exif::SHORT.','.Exif::LONG,                        # Bytes per compressed strip
 139                                         'JPEGInterchangeFormat' => Exif::SHORT.','.Exif::LONG,          # Offset to JPEG SOI
 140                                         'JPEGInterchangeFormatLength' => Exif::SHORT.','.Exif::LONG,    # Bytes of JPEG data
 141                                 ),
 142
 143                                 # Tags relating to image data characteristics
 144                                 'characteristics' => array(
 145                                         'TransferFunction' => Exif::SHORT,              # Transfer function
 146                                         'WhitePoint' => Exif::RATIONAL,         # White point chromaticity
 147                                         'PrimaryChromaticities' => Exif::RATIONAL,      # Chromaticities of primarities
 148                                         'YCbCrCoefficients' => Exif::RATIONAL,  # Color space transformation matrix coefficients #p27
 149                                         'ReferenceBlackWhite' => Exif::RATIONAL # Pair of black and white reference values
 150                                 ),
 151
 152                                 # Other tags
 153                                 'other' => array(
 154                                         'DateTime' => Exif::ASCII,            # File change date and time
 155                                         'ImageDescription' => Exif::ASCII,    # Image title
 156                                         'Make' => Exif::ASCII,                # Image input equipment manufacturer
 157                                         'Model' => Exif::ASCII,               # Image input equipment model
 158                                         'Software' => Exif::ASCII,            # Software used
 159                                         'Artist' => Exif::ASCII,              # Person who created the image
 160                                         'Copyright' => Exif::ASCII,           # Copyright holder
 161                                 ),
 162                         ),
 163
 164                         # Exif IFD Attribute Information (p30-31)
 165                         'exif' => array(
 166                                 # Tags relating to version
 167                                 'version' => array(
 168                                         # TODO: NOTE: Nonexistence of this field is taken to mean nonconformance
 169                                         # to the EXIF 2.1 AND 2.2 standards
 170                                         'ExifVersion' => Exif::UNDEFINED,       # Exif version
 171                                         'FlashpixVersion' => Exif::UNDEFINED, # Supported Flashpix version #p32
 172                                 ),
 173
 174                                 # Tags relating to Image Data Characteristics
 175                                 'characteristics' => array(
 176                                         'ColorSpace' => Exif::SHORT,            # Color space information #p32
 177                                 ),
 178
 179                                 # Tags relating to image configuration
 180                                 'configuration' => array(
 181                                         'ComponentsConfiguration' => Exif::UNDEFINED,           # Meaning of each component #p33
 182                                         'CompressedBitsPerPixel' => Exif::RATIONAL,             # Image compression mode
 183                                         'PixelYDimension' => Exif::SHORT.','.Exif::LONG,        # Valid image width
 184                                         'PixelXDimension' => Exif::SHORT.','.Exif::LONG,        # Valind image height
 185                                 ),
 186
 187                                 # Tags relating to related user information
 188                                 'user' => array(
 189                                         'MakerNote' => Exif::UNDEFINED,                 # Manufacturer notes
 190                                         'UserComment' => Exif::UNDEFINED,                       # User comments #p34
 191                                 ),
 192
 193                                 # Tags relating to related file information
 194                                 'related' => array(
 195                                         'RelatedSoundFile' => Exif::ASCII,                      # Related audio file
 196                                 ),
 197
 198                                 # Tags relating to date and time
 199                                 'dateandtime' => array(
 200                                         'DateTimeOriginal' => Exif::ASCII,                      # Date and time of original data generation #p36
 201                                         'DateTimeDigitized' => Exif::ASCII,                     # Date and time of original data generation
 202                                         'SubSecTime' => Exif::ASCII,                            # DateTime subseconds
 203                                         'SubSecTimeOriginal' => Exif::ASCII,                    # DateTimeOriginal subseconds
 204                                         'SubSecTimeDigitized' => Exif::ASCII,                   # DateTimeDigitized subseconds
 205                                 ),
 206
 207                                 # Tags relating to picture-taking conditions (p31)
 208                                 'conditions' => array(
 209                                         'ExposureTime' => Exif::RATIONAL,                       # Exposure time
 210                                         'FNumber' => Exif::RATIONAL,                            # F Number
 211                                         'ExposureProgram' => Exif::SHORT,                       # Exposure Program #p38
 212                                         'SpectralSensitivity' => Exif::ASCII,                   # Spectral sensitivity
 213                                         'ISOSpeedRatings' => Exif::SHORT,                       # ISO speed rating
 214                                         'OECF' => Exif::UNDEFINED,                              # Optoelectronic conversion factor
 215                                         'ShutterSpeedValue' => Exif::SRATIONAL,         # Shutter speed
 216                                         'ApertureValue' => Exif::RATIONAL,                      # Aperture
 217                                         'BrightnessValue' => Exif::SRATIONAL,                   # Brightness
 218                                         'ExposureBiasValue' => Exif::SRATIONAL,         # Exposure bias
 219                                         'MaxApertureValue' => Exif::RATIONAL,                   # Maximum land aperture
 220                                         'SubjectDistance' => Exif::RATIONAL,                    # Subject distance
 221                                         'MeteringMode' => Exif::SHORT,                  # Metering mode #p40
 222                                         'LightSource' => Exif::SHORT,                           # Light source #p40-41
 223                                         'Flash' => Exif::SHORT,                         # Flash #p41-42
 224                                         'FocalLength' => Exif::RATIONAL,                        # Lens focal length
 225                                         'SubjectArea' => Exif::SHORT,                           # Subject area
 226                                         'FlashEnergy' => Exif::RATIONAL,                        # Flash energy
 227                                         'SpatialFrequencyResponse' => Exif::UNDEFINED,  # Spatial frequency response
 228                                         'FocalPlaneXResolution' => Exif::RATIONAL,              # Focal plane X resolution
 229                                         'FocalPlaneYResolution' => Exif::RATIONAL,              # Focal plane Y resolution
 230                                         'FocalPlaneResolutionUnit' => Exif::SHORT,              # Focal plane resolution unit #p46
 231                                         'SubjectLocation' => Exif::SHORT,                       # Subject location
 232                                         'ExposureIndex' => Exif::RATIONAL,                      # Exposure index
 233                                         'SensingMethod' => Exif::SHORT,                 # Sensing method #p46
 234                                         'FileSource' => Exif::UNDEFINED,                        # File source #p47
 235                                         'SceneType' => Exif::UNDEFINED,                 # Scene type #p47
 236                                         'CFAPattern' => Exif::UNDEFINED,                        # CFA pattern
 237                                         'CustomRendered' => Exif::SHORT,                        # Custom image processing #p48
 238                                         'ExposureMode' => Exif::SHORT,                  # Exposure mode #p48
 239                                         'WhiteBalance' => Exif::SHORT,                  # White Balance #p49
 240                                         'DigitalZoomRatio' => Exif::RATIONAL,                   # Digital zoom ration
 241                                         'FocalLengthIn35mmFilm' => Exif::SHORT,         # Focal length in 35 mm film
 242                                         'SceneCaptureType' => Exif::SHORT,                      # Scene capture type #p49
 243                                         'GainControl' => Exif::RATIONAL,                        # Scene control #p49-50
 244                                         'Contrast' => Exif::SHORT,                              # Contrast #p50
 245                                         'Saturation' => Exif::SHORT,                            # Saturation #p50
 246                                         'Sharpness' => Exif::SHORT,                             # Sharpness #p50
 247                                         'DeviceSettingDescription' => Exif::UNDEFINED,  # Desice settings description
 248                                         'SubjectDistanceRange' => Exif::SHORT,          # Subject distance range #p51
 249                                 ),
 250
 251                                 'other' => array(
 252                                         'ImageUniqueID' => Exif::ASCII, # Unique image ID
 253                                 ),
 254                         ),
 255
 256                         # GPS Attribute Information (p52)
 257                         'gps' => array(
 258                                 'GPSVersionID' => Exif::BYTE,                   # GPS tag version
 259                                 'GPSLatitudeRef' => Exif::ASCII,                # North or South Latitude #p52-53
 260                                 'GPSLatitude' => Exif::RATIONAL,                # Latitude
 261                                 'GPSLongitudeRef' => Exif::ASCII,               # East or West Longitude #p53
 262                                 'GPSLongitude' => Exif::RATIONAL,               # Longitude
 263                                 'GPSAltitudeRef' => Exif::BYTE,         # Altitude reference
 264                                 'GPSAltitude' => Exif::RATIONAL,                # Altitude
 265                                 'GPSTimeStamp' => Exif::RATIONAL,               # GPS time (atomic clock)
 266                                 'GPSSatellites' => Exif::ASCII,         # Satellites used for measurement
 267                                 'GPSStatus' => Exif::ASCII,                     # Receiver status #p54
 268                                 'GPSMeasureMode' => Exif::ASCII,                # Measurement mode #p54-55
 269                                 'GPSDOP' => Exif::RATIONAL,                     # Measurement precision
 270                                 'GPSSpeedRef' => Exif::ASCII,                   # Speed unit #p55
 271                                 'GPSSpeed' => Exif::RATIONAL,                   # Speed of GPS receiver
 272                                 'GPSTrackRef' => Exif::ASCII,                   # Reference for direction of movement #p55
 273                                 'GPSTrack' => Exif::RATIONAL,                   # Direction of movement
 274                                 'GPSImgDirectionRef' => Exif::ASCII,            # Reference for direction of image #p56
 275                                 'GPSImgDirection' => Exif::RATIONAL,            # Direction of image
 276                                 'GPSMapDatum' => Exif::ASCII,                   # Geodetic survey data used
 277                                 'GPSDestLatitudeRef' => Exif::ASCII,            # Reference for latitude of destination #p56
 278                                 'GPSDestLatitude' => Exif::RATIONAL,            # Latitude destination
 279                                 'GPSDestLongitudeRef' => Exif::ASCII,           # Reference for longitude of destination #p57
 280                                 'GPSDestLongitude' => Exif::RATIONAL,           # Longitude of destination
 281                                 'GPSDestBearingRef' => Exif::ASCII,             # Reference for bearing of destination #p57
 282                                 'GPSDestBearing' => Exif::RATIONAL,             # Bearing of destination
 283                                 'GPSDestDistanceRef' => Exif::ASCII,            # Reference for distance to destination #p57-58
 284                                 'GPSDestDistance' => Exif::RATIONAL,            # Distance to destination
 285                                 'GPSProcessingMethod' => Exif::UNDEFINED,       # Name of GPS processing method
 286                                 'GPSAreaInformation' => Exif::UNDEFINED,        # Name of GPS area
 287                                 'GPSDateStamp' => Exif::ASCII,          # GPS date
 288                                 'GPSDifferential' => Exif::SHORT,               # GPS differential correction
 289                         ),
 290                 );
 291
 292                 $this->file = $file;
 293                 $this->basename = wfBaseName( $this->file );
 294
 295                 $this->makeFlatExifTags();
 296
 297                 $this->debugFile( $this->basename, __FUNCTION__, true );
 298                 wfSuppressWarnings();
 299                 $data = exif_read_data( $this->file );
 300                 wfRestoreWarnings();
 301                 /**
 302                  * exif_read_data() will return false on invalid input, such as
 303                  * when somebody uploads a file called something.jpeg
 304                  * containing random gibberish.
 305                  */
 306                 $this->mRawExifData = $data ? $data : array();
 307
 308                 $this->makeFilteredData();
 309                 $this->makeFormattedData();
 310
 311                 $this->debugFile( __FUNCTION__, false );
 312         }
 313
 314         /**#@+
 315          * @private
 316          */
 317         /**
 318          * Generate a flat list of the exif tags
 319          */
 320         function makeFlatExifTags() {
 321                 $this->extractTags( $this->mExifTags );
 322         }
 323
 324         /**
 325          * A recursing extractor function used by makeFlatExifTags()
 326          *
 327          * Note: This used to use an array_walk function, but it made PHP5
 328          * segfault, see `cvs diff -u -r 1.4 -r 1.5 Exif.php`
 329          */
 330         function extractTags( &$tagset ) {
 331                 foreach( $tagset as $key => $val ) {
 332                         if( is_array( $val ) ) {
 333                                 $this->extractTags( $val );
 334                         } else {
 335                                 $this->mFlatExifTags[$key] = $val;
 336                         }
 337                 }
 338         }
 339
 340         /**
 341          * Make $this->mFilteredExifData
 342          */
 343         function makeFilteredData() {
 344                 $this->mFilteredExifData = $this->mRawExifData;
 345
 346                 foreach( $this->mFilteredExifData as $k => $v ) {
 347                         if ( !in_array( $k, array_keys( $this->mFlatExifTags ) ) ) {
 348                                 $this->debug( $v, __FUNCTION__, "'$k' is not a valid Exif tag" );
 349                                 unset( $this->mFilteredExifData[$k] );
 350                         }
 351                 }
 352
 353                 foreach( $this->mFilteredExifData as $k => $v ) {
 354                         if ( !$this->validate($k, $v) ) {
 355                                 $this->debug( $v, __FUNCTION__, "'$k' contained invalid data" );
 356                                 unset( $this->mFilteredExifData[$k] );
 357                         }
 358                 }
 359         }
 360
 361         /**
 362          * @todo document
 363          */
 364         function makeFormattedData( ) {
 365                 $format = new FormatExif( $this->getFilteredData() );
 366                 $this->mFormattedExifData = $format->getFormattedData();
 367         }
 368         /**#@-*/
 369
 370         /**#@+
 371          * @return array
 372          */
 373         /**
 374          * Get $this->mRawExifData
 375          */
 376         function getData() {
 377                 return $this->mRawExifData;
 378         }
 379
 380         /**
 381          * Get $this->mFilteredExifData
 382          */
 383         function getFilteredData() {
 384                 return $this->mFilteredExifData;
 385         }
 386
 387         /**
 388          * Get $this->mFormattedExifData
 389          */
 390         function getFormattedData() {
 391                 return $this->mFormattedExifData;
 392         }
 393         /**#@-*/
 394
 395         /**
 396          * The version of the output format
 397          *
 398          * Before the actual metadata information is saved in the database we
 399          * strip some of it since we don't want to save things like thumbnails
 400          * which usually accompany Exif data. This value gets saved in the
 401          * database along with the actual Exif data, and if the version in the
 402          * database doesn't equal the value returned by this function the Exif
 403          * data is regenerated.
 404          *
 405          * @return int
 406          */
 407         public static function version() {
 408                 return 1; // We don't need no bloddy constants!
 409         }
 410
 411         /**#@+
 412          * Validates if a tag value is of the type it should be according to the Exif spec
 413          *
 414          * @private
 415          *
 416          * @param $in Mixed: the input value to check
 417          * @return bool
 418          */
 419         function isByte( $in ) {
 420                 if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 255 ) {
 421                         $this->debug( $in, __FUNCTION__, true );
 422                         return true;
 423                 } else {
 424                         $this->debug( $in, __FUNCTION__, false );
 425                         return false;
 426                 }
 427         }
 428
 429         function isASCII( $in ) {
 430                 if ( is_array( $in ) ) {
 431                         return false;
 432                 }
 433
 434                 if ( preg_match( "/[^\x0a\x20-\x7e]/", $in ) ) {
 435                         $this->debug( $in, __FUNCTION__, 'found a character not in our whitelist' );
 436                         return false;
 437                 }
 438
 439                 if ( preg_match( '/^\s*$/', $in ) ) {
 440                         $this->debug( $in, __FUNCTION__, 'input consisted solely of whitespace' );
 441                         return false;
 442                 }
 443
 444                 return true;
 445         }
 446
 447         function isShort( $in ) {
 448                 if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 65536 ) {
 449                         $this->debug( $in, __FUNCTION__, true );
 450                         return true;
 451                 } else {
 452                         $this->debug( $in, __FUNCTION__, false );
 453                         return false;
 454                 }
 455         }
 456
 457         function isLong( $in ) {
 458                 if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 4294967296 ) {
 459                         $this->debug( $in, __FUNCTION__, true );
 460                         return true;
 461                 } else {
 462                         $this->debug( $in, __FUNCTION__, false );
 463                         return false;
 464                 }
 465         }
 466
 467         function isRational( $in ) {
 468                 $m = array();
 469                 if ( !is_array( $in ) && @preg_match( '/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/', $in, $m ) ) { # Avoid division by zero
 470                         return $this->isLong( $m[1] ) && $this->isLong( $m[2] );
 471                 } else {
 472                         $this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
 473                         return false;
 474                 }
 475         }
 476
 477         function isUndefined( $in ) {
 478                 if ( !is_array( $in ) && preg_match( '/^\d{4}$/', $in ) ) { // Allow ExifVersion and FlashpixVersion
 479                         $this->debug( $in, __FUNCTION__, true );
 480                         return true;
 481                 } else {
 482                         $this->debug( $in, __FUNCTION__, false );
 483                         return false;
 484                 }
 485         }
 486
 487         function isSlong( $in ) {
 488                 if ( $this->isLong( abs( $in ) ) ) {
 489                         $this->debug( $in, __FUNCTION__, true );
 490                         return true;
 491                 } else {
 492                         $this->debug( $in, __FUNCTION__, false );
 493                         return false;
 494                 }
 495         }
 496
 497         function isSrational( $in ) {
 498                 $m = array();
 499                 if ( !is_array( $in ) && preg_match( '/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/', $in, $m ) ) { # Avoid division by zero
 500                         return $this->isSlong( $m[0] ) && $this->isSlong( $m[1] );
 501                 } else {
 502                         $this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
 503                         return false;
 504                 }
 505         }
 506         /**#@-*/
 507
 508         /**
 509          * Validates if a tag has a legal value according to the Exif spec
 510          *
 511          * @private
 512          *
 513          * @param $tag String: the tag to check.
 514          * @param $val Mixed: the value of the tag.
 515          * @return bool
 516          */
 517         function validate( $tag, $val ) {
 518                 $debug = "tag is '$tag'";
 519                 // Does not work if not typecast
 520                 switch( (string)$this->mFlatExifTags[$tag] ) {
 521                         case (string)Exif::BYTE:
 522                                 $this->debug( $val, __FUNCTION__, $debug );
 523                                 return $this->isByte( $val );
 524                         case (string)Exif::ASCII:
 525                                 $this->debug( $val, __FUNCTION__, $debug );
 526                                 return $this->isASCII( $val );
 527                         case (string)Exif::SHORT:
 528                                 $this->debug( $val, __FUNCTION__, $debug );
 529                                 return $this->isShort( $val );
 530                         case (string)Exif::LONG:
 531                                 $this->debug( $val, __FUNCTION__, $debug );
 532                                 return $this->isLong( $val );
 533                         case (string)Exif::RATIONAL:
 534                                 $this->debug( $val, __FUNCTION__, $debug );
 535                                 return $this->isRational( $val );
 536                         case (string)Exif::UNDEFINED:
 537                                 $this->debug( $val, __FUNCTION__, $debug );
 538                                 return $this->isUndefined( $val );
 539                         case (string)Exif::SLONG:
 540                                 $this->debug( $val, __FUNCTION__, $debug );
 541                                 return $this->isSlong( $val );
 542                         case (string)Exif::SRATIONAL:
 543                                 $this->debug( $val, __FUNCTION__, $debug );
 544                                 return $this->isSrational( $val );
 545                         case (string)Exif::SHORT.','.Exif::LONG:
 546                                 $this->debug( $val, __FUNCTION__, $debug );
 547                                 return $this->isShort( $val ) || $this->isLong( $val );
 548                         default:
 549                                 $this->debug( $val, __FUNCTION__, "The tag '$tag' is unknown" );
 550                                 return false;
 551                 }
 552         }
 553
 554         /**
 555          * Convenience function for debugging output
 556          *
 557          * @private
 558          *
 559          * @param $in Mixed:
 560          * @param $fname String:
 561          * @param $action Mixed: , default NULL.
 562          */
 563         function debug( $in, $fname, $action = null ) {
 564                 if ( !$this->log ) {
 565                         return;
 566                 }
 567                 $type = gettype( $in );
 568                 $class = ucfirst( __CLASS__ );
 569                 if ( $type === 'array' )
 570                         $in = print_r( $in, true );
 571
 572                 if ( $action === true )
 573                         wfDebugLog( $this->log, "$class::$fname: accepted: '$in' (type: $type)\n");
 574                 elseif ( $action === false )
 575                         wfDebugLog( $this->log, "$class::$fname: rejected: '$in' (type: $type)\n");
 576                 elseif ( $action === null )
 577                         wfDebugLog( $this->log, "$class::$fname: input was: '$in' (type: $type)\n");
 578                 else
 579                         wfDebugLog( $this->log, "$class::$fname: $action (type: $type; content: '$in')\n");
 580         }
 581
 582         /**
 583          * Convenience function for debugging output
 584          *
 585          * @private
 586          *
 587          * @param $fname String: the name of the function calling this function
 588          * @param $io Boolean: Specify whether we're beginning or ending
 589          */
 590         function debugFile( $fname, $io ) {
 591                 if ( !$this->log ) {
 592                         return;
 593                 }
 594                 $class = ucfirst( __CLASS__ );
 595                 if ( $io ) {
 596                         wfDebugLog( $this->log, "$class::$fname: begin processing: '{$this->basename}'\n" );
 597                 } else {
 598                         wfDebugLog( $this->log, "$class::$fname: end processing: '{$this->basename}'\n" );
 599                 }
 600         }
 601
 602 }
 603
 604 /**
 605  * @todo document (e.g. one-sentence class-overview description)
 606  * @ingroup Media
 607  */
 608 class FormatExif {
 609         /**
 610          * The Exif data to format
 611          *
 612          * @var array
 613          * @private
 614          */
 615         var $mExif;
 616
 617         /**
 618          * Constructor
 619          *
 620          * @param $exif Array: the Exif data to format ( as returned by
 621          *                    Exif::getFilteredData() )
 622          */
 623         function __construct( $exif ) {
 624                 $this->mExif = $exif;
 625         }
 626
 627         /**
 628          * Numbers given by Exif user agents are often magical, that is they
 629          * should be replaced by a detailed explanation depending on their
 630          * value which most of the time are plain integers. This function
 631          * formats Exif values into human readable form.
 632          *
 633          * @return array
 634          */
 635         function getFormattedData() {
 636                 global $wgLang;
 637
 638                 $tags =& $this->mExif;
 639
 640                 $resolutionunit = !isset( $tags['ResolutionUnit'] ) || $tags['ResolutionUnit'] == 2 ? 2 : 3;
 641                 unset( $tags['ResolutionUnit'] );
 642
 643                 foreach( $tags as $tag => $val ) {
 644                         switch( $tag ) {
 645                         case 'Compression':
 646                                 switch( $val ) {
 647                                 case 1: case 6:
 648                                         $tags[$tag] = $this->msg( $tag, $val );
 649                                         break;
 650                                 default:
 651                                         $tags[$tag] = $val;
 652                                         break;
 653                                 }
 654                                 break;
 655
 656                         case 'PhotometricInterpretation':
 657                                 switch( $val ) {
 658                                 case 2: case 6:
 659                                         $tags[$tag] = $this->msg( $tag, $val );
 660                                         break;
 661                                 default:
 662                                         $tags[$tag] = $val;
 663                                         break;
 664                                 }
 665                                 break;
 666
 667                         case 'Orientation':
 668                                 switch( $val ) {
 669                                 case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 670                                         $tags[$tag] = $this->msg( $tag, $val );
 671                                         break;
 672                                 default:
 673                                         $tags[$tag] = $val;
 674                                         break;
 675                                 }
 676                                 break;
 677
 678                         case 'PlanarConfiguration':
 679                                 switch( $val ) {
 680                                 case 1: case 2:
 681                                         $tags[$tag] = $this->msg( $tag, $val );
 682                                         break;
 683                                 default:
 684                                         $tags[$tag] = $val;
 685                                         break;
 686                                 }
 687                                 break;
 688
 689                         // TODO: YCbCrSubSampling
 690                         // TODO: YCbCrPositioning
 691
 692                         case 'XResolution':
 693                         case 'YResolution':
 694                                 switch( $resolutionunit ) {
 695                                         case 2:
 696                                                 $tags[$tag] = $this->msg( 'XYResolution', 'i', $this->formatNum( $val ) );
 697                                                 break;
 698                                         case 3:
 699                                                 $this->msg( 'XYResolution', 'c', $this->formatNum( $val ) );
 700                                                 break;
 701                                         default:
 702                                                 $tags[$tag] = $val;
 703                                                 break;
 704                                 }
 705                                 break;
 706
 707                         // TODO: YCbCrCoefficients  #p27 (see annex E)
 708                         case 'ExifVersion': case 'FlashpixVersion':
 709                                 $tags[$tag] = "$val"/100;
 710                                 break;
 711
 712                         case 'ColorSpace':
 713                                 switch( $val ) {
 714                                 case 1: case 'FFFF.H':
 715                                         $tags[$tag] = $this->msg( $tag, $val );
 716                                         break;
 717                                 default:
 718                                         $tags[$tag] = $val;
 719                                         break;
 720                                 }
 721                                 break;
 722
 723                         case 'ComponentsConfiguration':
 724                                 switch( $val ) {
 725                                 case 0: case 1: case 2: case 3: case 4: case 5: case 6:
 726                                         $tags[$tag] = $this->msg( $tag, $val );
 727                                         break;
 728                                 default:
 729                                         $tags[$tag] = $val;
 730                                         break;
 731                                 }
 732                                 break;
 733
 734                         case 'DateTime':
 735                         case 'DateTimeOriginal':
 736                         case 'DateTimeDigitized':
 737                                 if( $val == '0000:00:00 00:00:00' ) {
 738                                         $tags[$tag] = wfMsg('exif-unknowndate');
 739                                 } elseif( preg_match( '/^(?:\d{4}):(?:\d\d):(?:\d\d) (?:\d\d):(?:\d\d):(?:\d\d)$/', $val ) ) {
 740                                         $tags[$tag] = $wgLang->timeanddate( wfTimestamp(TS_MW, $val) );
 741                                 }
 742                                 break;
 743
 744                         case 'ExposureProgram':
 745                                 switch( $val ) {
 746                                 case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 747                                         $tags[$tag] = $this->msg( $tag, $val );
 748                                         break;
 749                                 default:
 750                                         $tags[$tag] = $val;
 751                                         break;
 752                                 }
 753                                 break;
 754
 755                         case 'SubjectDistance':
 756                                 $tags[$tag] = $this->msg( $tag, '', $this->formatNum( $val ) );
 757                                 break;
 758
 759                         case 'MeteringMode':
 760                                 switch( $val ) {
 761                                 case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 255:
 762                                         $tags[$tag] = $this->msg( $tag, $val );
 763                                         break;
 764                                 default:
 765                                         $tags[$tag] = $val;
 766                                         break;
 767                                 }
 768                                 break;
 769
 770                         case 'LightSource':
 771                                 switch( $val ) {
 772                                 case 0: case 1: case 2: case 3: case 4: case 9: case 10: case 11:
 773                                 case 12: case 13: case 14: case 15: case 17: case 18: case 19: case 20:
 774                                 case 21: case 22: case 23: case 24: case 255:
 775                                         $tags[$tag] = $this->msg( $tag, $val );
 776                                         break;
 777                                 default:
 778                                         $tags[$tag] = $val;
 779                                         break;
 780                                 }
 781                                 break;
 782
 783                         case 'Flash':
 784                                 $flashDecode = array(
 785                                         'fired'    => $val & bindec( '00000001' ),
 786                                         'return'   => ($val & bindec( '00000110' )) >> 1,
 787                                         'mode'     => ($val & bindec( '00011000' )) >> 3,
 788                                         'function' => ($val & bindec( '00100000' )) >> 5,
 789                                         'redeye'   => ($val & bindec( '01000000' )) >> 6,
 790 //                                      'reserved' => ($val & bindec( '10000000' )) >> 7,
 791                                 );
 792
 793                                 # We do not need to handle unknown values since all are used.
 794                                 foreach( $flashDecode as $subTag => $subValue ) {
 795                                         # We do not need any message for zeroed values.
 796                                         if( $subTag != 'fired' && $subValue == 0) {
 797                                                 continue;
 798                                         }
 799                                         $fullTag = $tag . '-' . $subTag ;
 800                                         $flashMsgs[] = $this->msg( $fullTag, $subValue );
 801                                 }
 802                                 $tags[$tag] = $wgLang->commaList( $flashMsgs );
 803                         break;
 804
 805                         case 'FocalPlaneResolutionUnit':
 806                                 switch( $val ) {
 807                                 case 2:
 808                                         $tags[$tag] = $this->msg( $tag, $val );
 809                                         break;
 810                                 default:
 811                                         $tags[$tag] = $val;
 812                                         break;
 813                                 }
 814                                 break;
 815
 816                         case 'SensingMethod':
 817                                 switch( $val ) {
 818                                 case 1: case 2: case 3: case 4: case 5: case 7: case 8:
 819                                         $tags[$tag] = $this->msg( $tag, $val );
 820                                         break;
 821                                 default:
 822                                         $tags[$tag] = $val;
 823                                         break;
 824                                 }
 825                                 break;
 826
 827                         case 'FileSource':
 828                                 switch( $val ) {
 829                                 case 3:
 830                                         $tags[$tag] = $this->msg( $tag, $val );
 831                                         break;
 832                                 default:
 833                                         $tags[$tag] = $val;
 834                                         break;
 835                                 }
 836                                 break;
 837
 838                         case 'SceneType':
 839                                 switch( $val ) {
 840                                 case 1:
 841                                         $tags[$tag] = $this->msg( $tag, $val );
 842                                         break;
 843                                 default:
 844                                         $tags[$tag] = $val;
 845                                         break;
 846                                 }
 847                                 break;
 848
 849                         case 'CustomRendered':
 850                                 switch( $val ) {
 851                                 case 0: case 1:
 852                                         $tags[$tag] = $this->msg( $tag, $val );
 853                                         break;
 854                                 default:
 855                                         $tags[$tag] = $val;
 856                                         break;
 857                                 }
 858                                 break;
 859
 860                         case 'ExposureMode':
 861                                 switch( $val ) {
 862                                 case 0: case 1: case 2:
 863                                         $tags[$tag] = $this->msg( $tag, $val );
 864                                         break;
 865                                 default:
 866                                         $tags[$tag] = $val;
 867                                         break;
 868                                 }
 869                                 break;
 870
 871                         case 'WhiteBalance':
 872                                 switch( $val ) {
 873                                 case 0: case 1:
 874                                         $tags[$tag] = $this->msg( $tag, $val );
 875                                         break;
 876                                 default:
 877                                         $tags[$tag] = $val;
 878                                         break;
 879                                 }
 880                                 break;
 881
 882                         case 'SceneCaptureType':
 883                                 switch( $val ) {
 884                                 case 0: case 1: case 2: case 3:
 885                                         $tags[$tag] = $this->msg( $tag, $val );
 886                                         break;
 887                                 default:
 888                                         $tags[$tag] = $val;
 889                                         break;
 890                                 }
 891                                 break;
 892
 893                         case 'GainControl':
 894                                 switch( $val ) {
 895                                 case 0: case 1: case 2: case 3: case 4:
 896                                         $tags[$tag] = $this->msg( $tag, $val );
 897                                         break;
 898                                 default:
 899                                         $tags[$tag] = $val;
 900                                         break;
 901                                 }
 902                                 break;
 903
 904                         case 'Contrast':
 905                                 switch( $val ) {
 906                                 case 0: case 1: case 2:
 907                                         $tags[$tag] = $this->msg( $tag, $val );
 908                                         break;
 909                                 default:
 910                                         $tags[$tag] = $val;
 911                                         break;
 912                                 }
 913                                 break;
 914
 915                         case 'Saturation':
 916                                 switch( $val ) {
 917                                 case 0: case 1: case 2:
 918                                         $tags[$tag] = $this->msg( $tag, $val );
 919                                         break;
 920                                 default:
 921                                         $tags[$tag] = $val;
 922                                         break;
 923                                 }
 924                                 break;
 925
 926                         case 'Sharpness':
 927                                 switch( $val ) {
 928                                 case 0: case 1: case 2:
 929                                         $tags[$tag] = $this->msg( $tag, $val );
 930                                         break;
 931                                 default:
 932                                         $tags[$tag] = $val;
 933                                         break;
 934                                 }
 935                                 break;
 936
 937                         case 'SubjectDistanceRange':
 938                                 switch( $val ) {
 939                                 case 0: case 1: case 2: case 3:
 940                                         $tags[$tag] = $this->msg( $tag, $val );
 941                                         break;
 942                                 default:
 943                                         $tags[$tag] = $val;
 944                                         break;
 945                                 }
 946                                 break;
 947
 948                         case 'GPSLatitudeRef':
 949                         case 'GPSDestLatitudeRef':
 950                                 switch( $val ) {
 951                                 case 'N': case 'S':
 952                                         $tags[$tag] = $this->msg( 'GPSLatitude', $val );
 953                                         break;
 954                                 default:
 955                                         $tags[$tag] = $val;
 956                                         break;
 957                                 }
 958                                 break;
 959
 960                         case 'GPSLongitudeRef':
 961                         case 'GPSDestLongitudeRef':
 962                                 switch( $val ) {
 963                                 case 'E': case 'W':
 964                                         $tags[$tag] = $this->msg( 'GPSLongitude', $val );
 965                                         break;
 966                                 default:
 967                                         $tags[$tag] = $val;
 968                                         break;
 969                                 }
 970                                 break;
 971
 972                         case 'GPSStatus':
 973                                 switch( $val ) {
 974                                 case 'A': case 'V':
 975                                         $tags[$tag] = $this->msg( $tag, $val );
 976                                         break;
 977                                 default:
 978                                         $tags[$tag] = $val;
 979                                         break;
 980                                 }
 981                                 break;
 982
 983                         case 'GPSMeasureMode':
 984                                 switch( $val ) {
 985                                 case 2: case 3:
 986                                         $tags[$tag] = $this->msg( $tag, $val );
 987                                         break;
 988                                 default:
 989                                         $tags[$tag] = $val;
 990                                         break;
 991                                 }
 992                                 break;
 993
 994                         case 'GPSSpeedRef':
 995                         case 'GPSDestDistanceRef':
 996                                 switch( $val ) {
 997                                 case 'K': case 'M': case 'N':
 998                                         $tags[$tag] = $this->msg( 'GPSSpeed', $val );
 999                                         break;
1000                                 default:
1001                                         $tags[$tag] = $val;
1002                                         break;
1003                                 }
1004                                 break;
1005
1006                         case 'GPSTrackRef':
1007                         case 'GPSImgDirectionRef':
1008                         case 'GPSDestBearingRef':
1009                                 switch( $val ) {
1010                                 case 'T': case 'M':
1011                                         $tags[$tag] = $this->msg( 'GPSDirection', $val );
1012                                         break;
1013                                 default:
1014                                         $tags[$tag] = $val;
1015                                         break;
1016                                 }
1017                                 break;
1018
1019                         case 'GPSDateStamp':
1020                                 $tags[$tag] = $wgLang->date( substr( $val, 0, 4 ) . substr( $val, 5, 2 ) . substr( $val, 8, 2 ) . '000000' );
1021                                 break;
1022
1023                         // This is not in the Exif standard, just a special
1024                         // case for our purposes which enables wikis to wikify
1025                         // the make, model and software name to link to their articles.
1026                         case 'Make':
1027                         case 'Model':
1028                         case 'Software':
1029                                 $tags[$tag] = $this->msg( $tag, '', $val );
1030                                 break;
1031
1032                         case 'ExposureTime':
1033                                 // Show the pretty fraction as well as decimal version
1034                                 $tags[$tag] = wfMsg( 'exif-exposuretime-format',
1035                                         $this->formatFraction( $val ), $this->formatNum( $val ) );
1036                                 break;
1037
1038                         case 'FNumber':
1039                                 $tags[$tag] = wfMsg( 'exif-fnumber-format',
1040                                         $this->formatNum( $val ) );
1041                                 break;
1042
1043                         case 'FocalLength':
1044                                 $tags[$tag] = wfMsg( 'exif-focallength-format',
1045                                         $this->formatNum( $val ) );
1046                                 break;
1047
1048                         // Do not transform fields with pure text.
1049                         // For some languages the formatNum() conversion results to wrong output like
1050                         // foo,bar@example,com or foo٫bar@example٫com
1051                         case 'ImageDescription':
1052                         case 'Artist':
1053                         case 'Copyright':
1054                                 $tags[$tag] = htmlspecialchars( $val );
1055                                 break;
1056                         default:
1057                                 $tags[$tag] = $this->formatNum( $val );
1058                                 break;
1059                         }
1060                 }
1061
1062                 return $tags;
1063         }
1064
1065         /**
1066          * Convenience function for getFormattedData()
1067          *
1068          * @private
1069          *
1070          * @param $tag String: the tag name to pass on
1071          * @param $val String: the value of the tag
1072          * @param $arg String: an argument to pass ($1)
1073          * @return string A wfMsg of "exif-$tag-$val" in lower case
1074          */
1075         function msg( $tag, $val, $arg = null ) {
1076                 global $wgContLang;
1077
1078                 if ($val === '')
1079                         $val = 'value';
1080                 return wfMsg( $wgContLang->lc( "exif-$tag-$val" ), $arg );
1081         }
1082
1083         /**
1084          * Format a number, convert numbers from fractions into floating point
1085          * numbers
1086          *
1087          * @private
1088          *
1089          * @param $num Mixed: the value to format
1090          * @return mixed A floating point number or whatever we were fed
1091          */
1092         function formatNum( $num ) {
1093                 global $wgLang;
1094
1095                 $m = array();
1096                 if ( preg_match( '/^(\d+)\/(\d+)$/', $num, $m ) )
1097                         return $wgLang->formatNum( $m[2] != 0 ? $m[1] / $m[2] : $num );
1098                 else
1099                         return $wgLang->formatNum( $num );
1100         }
1101
1102         /**
1103          * Format a rational number, reducing fractions
1104          *
1105          * @private
1106          *
1107          * @param $num Mixed: the value to format
1108          * @return mixed A floating point number or whatever we were fed
1109          */
1110         function formatFraction( $num ) {
1111                 $m = array();
1112                 if ( preg_match( '/^(\d+)\/(\d+)$/', $num, $m ) ) {
1113                         $numerator = intval( $m[1] );
1114                         $denominator = intval( $m[2] );
1115                         $gcd = $this->gcd( $numerator, $denominator );
1116                         if( $gcd != 0 ) {
1117                                 // 0 shouldn't happen! ;)
1118                                 return $this->formatNum( $numerator / $gcd ) . '/' . $this->formatNum( $denominator / $gcd );
1119                         }
1120                 }
1121                 return $this->formatNum( $num );
1122         }
1123
1124         /**
1125          * Calculate the greatest common divisor of two integers.
1126          *
1127          * @param $a Integer: FIXME
1128          * @param $b Integer: FIXME
1129          * @return int
1130          * @private
1131          */
1132         function gcd( $a, $b ) {
1133                 /*
1134                         // http://en.wikipedia.org/wiki/Euclidean_algorithm
1135                         // Recursive form would be:
1136                         if( $b == 0 )
1137                                 return $a;
1138                         else
1139                                 return gcd( $b, $a % $b );
1140                 */
1141                 while( $b != 0 ) {
1142                         $remainder = $a % $b;
1143
1144                         // tail recursion...
1145                         $a = $b;
1146                         $b = $remainder;
1147                 }
1148                 return $a;
1149         }
1150 }