includes/Exif.php

   1 <?php
   2 if (defined('MEDIAWIKI')) {
   3 /**
   4  * @package MediaWiki
   5  * @subpackage Metadata
   6  *
   7  * @author Ævar Arnfjörð Bjarmason <avarab@gmail.com>
   8  * @copyright Copyright © 2005, Ævar Arnfjörð Bjarmason
   9  * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  * http://www.gnu.org/copyleft/gpl.html
  25  *
  26  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  27  * @bug 1555, 1947
  28  */
  29
  30 /**#@+
  31  * Exif tag type definition
  32  */
  33 define('MW_EXIF_BYTE', 1);              # An 8-bit unsigned integer.
  34 define('MW_EXIF_ASCII', 2);             # An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
  35 define('MW_EXIF_SHORT', 3);             # A 16-bit (2-byte) unsigned integer.
  36 define('MW_EXIF_LONG', 4);              # A 32-bit (4-byte) unsigned integer.
  37 define('MW_EXIF_RATIONAL', 5);          # Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
  38 define('MW_EXIF_UNDEFINED', 7);         # An 8-bit byte that can take any value depending on the field definition
  39 define('MW_EXIF_SLONG', 9);             # A 32-bit (4-byte) signed integer (2's complement notation),
  40 define('MW_EXIF_SRATIONAL', 10);        # Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.
  41 /**#@-*/
  42
  43
  44 /**
  45  * @package MediaWiki
  46  * @subpackage Metadata
  47  */
  48 class Exif {
  49         /**#@+
  50          * @var array
  51          */
  52
  53         /**
  54          * Exif tags grouped by category, the tagname itself is the key and the type
  55          * is the value, in the case of more than one possible value type they are
  56          * seperated by commas.
  57          *
  58          * @access private
  59          */
  60         var $mExif;
  61
  62         /**
  63          * A one dimentional array of all Exif tags
  64          */
  65         var $mFlatExif;
  66
  67         /**#@-*/
  68
  69         /**
  70          * Constructor
  71          */
  72         function Exif() {
  73                 /**
  74                  * Page numbers here refer to pages in the EXIF 2.2 standard
  75                  *
  76                  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  77                  */
  78                 $this->mExif = array(
  79                         # TIFF Rev. 6.0 Attribute Information (p22)
  80                         'tiff' => array(
  81                                 # Tags relating to image structure
  82                                 'structure' => array(
  83                                         'ImageWidth' => MW_EXIF_SHORT.','.MW_EXIF_LONG,         # Image width
  84                                         'ImageLength' => MW_EXIF_SHORT.','.MW_EXIF_LONG,        # Image height
  85                                         'BitsPerSample' => MW_EXIF_SHORT,                       # Number of bits per component
  86                                         # "When a primary image is JPEG compressed, this designation is not"
  87                                         # "necessary and is omitted." (p23)
  88                                         'Compression' => MW_EXIF_SHORT,                         # Compression scheme #p23
  89                                         'PhotometricInterpretation' => MW_EXIF_SHORT,           # Pixel composition #p23
  90                                         'Orientation' => MW_EXIF_SHORT,                         # Orientation of image #p24
  91                                         'SamplesPerPixel' => MW_EXIF_SHORT,                     # Number of components
  92                                         'PlanarConfiguration' => MW_EXIF_SHORT,                 # Image data arrangement #p24
  93                                         'YCbCrSubSampling' => MW_EXIF_SHORT,                    # Subsampling ratio of Y to C #p24
  94                                         'YCbCrPositioning' => MW_EXIF_SHORT,                    # Y and C positioning #p24-25
  95                                         'XResolution' => MW_EXIF_RATIONAL,                      # Image resolution in width direction
  96                                         'YResolution' => MW_EXIF_RATIONAL,                      # Image resolution in height direction
  97                                         'ResolutionUnit' => MW_EXIF_SHORT,                      # Unit of X and Y resolution #(p26)
  98                                 ),
  99
 100                                 # Tags relating to recording offset
 101                                 'offset' => array(
 102                                         'StripOffsets' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                       # Image data location
 103                                         'RowsPerStrip' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                       # Number of rows per strip
 104                                         'StripByteCounts' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                    # Bytes per compressed strip
 105                                         'JPEGInterchangeFormat' => MW_EXIF_SHORT.','.MW_EXIF_LONG,              # Offset to JPEG SOI
 106                                         'JPEGInterchangeFormatLength' => MW_EXIF_SHORT.','.MW_EXIF_LONG,        # Bytes of JPEG data
 107                                 ),
 108
 109                                 # Tags relating to image data characteristics
 110                                 'characteristics' => array(
 111                                         'TransferFunction' => MW_EXIF_SHORT,            # Transfer function
 112                                         'WhitePoint' => MW_EXIF_RATIONAL,               # White point chromaticity
 113                                         'PrimaryChromaticities' => MW_EXIF_RATIONAL,    # Chromaticities of primarities
 114                                         'YCbCrCoefficients' => MW_EXIF_RATIONAL,        # Color space transformation matrix coefficients #p27
 115                                         'ReferenceBlackWhite' => MW_EXIF_RATIONAL       # Pair of black and white reference values
 116                                 ),
 117
 118                                 # Other tags
 119                                 'other' => array(
 120                                         'DateTime' => MW_EXIF_ASCII,            # File change date and time
 121                                         'ImageDescription' => MW_EXIF_ASCII,    # Image title
 122                                         'Make' => MW_EXIF_ASCII,                # Image input equipment manufacturer
 123                                         'Model' => MW_EXIF_ASCII,               # Image input equipment model
 124                                         'Software' => MW_EXIF_ASCII,            # Software used
 125                                         'Artist' => MW_EXIF_ASCII,              # Person who created the image
 126                                         'Copyright' => MW_EXIF_ASCII,           # Copyright holder
 127                                 ),
 128                         ),
 129
 130                         # Exif IFD Attribute Information (p30-31)
 131                         'exif' => array(
 132                                 # Tags relating to version
 133                                 'version' => array(
 134                                         # TODO: NOTE: Nonexistence of this field is taken to mean nonconformance
 135                                         # to the EXIF 2.1 AND 2.2 standards
 136                                         'ExifVersion' => MW_EXIF_UNDEFINED,     # Exif version
 137                                         'FlashpixVersion' => MW_EXIF_UNDEFINED, # Supported Flashpix version #p32
 138                                 ),
 139
 140                                 # Tags relating to Image Data Characteristics
 141                                 'characteristics' => array(
 142                                         'ColorSpace' => MW_EXIF_SHORT,          # Color space information #p32
 143                                 ),
 144
 145                                 # Tags relating to image configuration
 146                                 'configuration' => array(
 147                                         'ComponentsConfiguration' => MW_EXIF_UNDEFINED,         # Meaning of each component #p33
 148                                         'CompressedBitsPerPixel' => MW_EXIF_RATIONAL,           # Image compression mode
 149                                         'PixelYDimension' => MW_EXIF_SHORT.','.MW_EXIF_LONG,    # Valid image width
 150                                         'PixelXDimension' => MW_EXIF_SHORT.','.MW_EXIF_LONG,    # Valind image height
 151                                 ),
 152
 153                                 # Tags relating to related user information
 154                                 'user' => array(
 155                                         'MakerNote' => MW_EXIF_UNDEFINED,                       # Manufacturer notes
 156                                         'UserComment' => MW_EXIF_UNDEFINED,                     # User comments #p34
 157                                 ),
 158
 159                                 # Tags relating to related file information
 160                                 'related' => array(
 161                                         'RelatedSoundFile' => MW_EXIF_ASCII,                    # Related audio file
 162                                 ),
 163
 164                                 # Tags relating to date and time
 165                                 'dateandtime' => array(
 166                                         'DateTimeOriginal' => MW_EXIF_ASCII,                    # Date and time of original data generation #p36
 167                                         'DateTimeDigitized' => MW_EXIF_ASCII,                   # Date and time of original data generation
 168                                         'SubSecTime' => MW_EXIF_ASCII,                          # DateTime subseconds
 169                                         'SubSecTimeOriginal' => MW_EXIF_ASCII,                  # DateTimeOriginal subseconds
 170                                         'SubSecTimeDigitized' => MW_EXIF_ASCII,                 # DateTimeDigitized subseconds
 171                                 ),
 172
 173                                 # Tags relating to picture-taking conditions (p31)
 174                                 'conditions' => array(
 175                                         'ExposureTime' => MW_EXIF_RATIONAL,                     # Exposure time
 176                                         'FNumber' => MW_EXIF_RATIONAL,                          # F Number
 177                                         'ExposureProgram' => MW_EXIF_SHORT,                     # Exposure Program #p38
 178                                         'SpectralSensitivity' => MW_EXIF_ASCII,                 # Spectral sensitivity
 179                                         'ISOSpeedRatings' => MW_EXIF_SHORT,                     # ISO speed rating
 180                                         'OECF' => MW_EXIF_UNDEFINED,                            # Optoelectronic conversion factor
 181                                         'ShutterSpeedValue' => MW_EXIF_SRATIONAL,               # Shutter speed
 182                                         'ApertureValue' => MW_EXIF_RATIONAL,                    # Aperture
 183                                         'BrightnessValue' => MW_EXIF_SRATIONAL,                 # Brightness
 184                                         'ExposureBiasValue' => MW_EXIF_SRATIONAL,               # Exposure bias
 185                                         'MaxApertureValue' => MW_EXIF_RATIONAL,                 # Maximum land aperture
 186                                         'SubjectDistance' => MW_EXIF_RATIONAL,                  # Subject distance
 187                                         'MeteringMode' => MW_EXIF_SHORT,                        # Metering mode #p40
 188                                         'LightSource' => MW_EXIF_SHORT,                         # Light source #p40-41
 189                                         'Flash' => MW_EXIF_SHORT,                               # Flash #p41-42
 190                                         'FocalLength' => MW_EXIF_RATIONAL,                      # Lens focal length
 191                                         'SubjectArea' => MW_EXIF_SHORT,                         # Subject area
 192                                         'FlashEnergy' => MW_EXIF_RATIONAL,                      # Flash energy
 193                                         'SpatialFrequencyResponse' => MW_EXIF_UNDEFINED,        # Spatial frequency response
 194                                         'FocalPlaneXResolution' => MW_EXIF_RATIONAL,            # Focal plane X resolution
 195                                         'FocalPlaneYResolution' => MW_EXIF_RATIONAL,            # Focal plane Y resolution
 196                                         'FocalPlaneResolutionUnit' => MW_EXIF_SHORT,            # Focal plane resolution unit
 197                                         'SubjectLocation' => MW_EXIF_SHORT,                     # Subject location
 198                                         'ExposureIndex' => MW_EXIF_RATIONAL,                    # Exposure index
 199                                         'SensingMethod' => MW_EXIF_SHORT,                       # Sensing method #p46
 200                                         'FileSource' => MW_EXIF_UNDEFINED,                      # File source #p47
 201                                         'SceneType' => MW_EXIF_UNDEFINED,                       # Scene type #p47
 202                                         'CFAPattern' => MW_EXIF_UNDEFINED,                      # CFA pattern
 203                                         'CustomRendered' => MW_EXIF_SHORT,                      # Custom image processing #p48
 204                                         'ExposureMode' => MW_EXIF_SHORT,                        # Exposure mode #p48
 205                                         'WhiteBalance' => MW_EXIF_SHORT,                        # White Balance #p49
 206                                         'DigitalZoomRatio' => MW_EXIF_RATIONAL,                 # Digital zoom ration
 207                                         'FocalLengthIn35mmFilm' => MW_EXIF_SHORT,               # Focal length in 35 mm film
 208                                         'SceneCaptureType' => MW_EXIF_SHORT,                    # Scene capture type #p49
 209                                         'GainControl' => MW_EXIF_RATIONAL,                      # Scene control #p49-50
 210                                         'Contrast' => MW_EXIF_SHORT,                            # Contrast #p50
 211                                         'Saturation' => MW_EXIF_SHORT,                          # Saturation #p50
 212                                         'Sharpness' => MW_EXIF_SHORT,                           # Sharpness #p50
 213                                         'DeviceSettingDescription' => MW_EXIF_UNDEFINED,        # Desice settings description
 214                                         'SubjectDistanceRange' => MW_EXIF_SHORT,                # Subject distance range #p51
 215                                 ),
 216
 217                                 'other' => array(
 218                                         'ImageUniqueID' => MW_EXIF_ASCII,       # Unique image ID
 219                                 ),
 220                         ),
 221
 222                         # GPS Attribute Information (p52)
 223                         'gps' => array(
 224                                 'GPSVersionID' => MW_EXIF_BYTE,                 # GPS tag version
 225                                 'GPSLatitudeRef' => MW_EXIF_ASCII,              # North or South Latitude #p52-53
 226                                 'GPSLatitude' => MW_EXIF_RATIONAL,              # Latitude
 227                                 'GPSLongitudeRef' => MW_EXIF_ASCII,             # East or West Longitude #p53
 228                                 'GPSLongitude' => MW_EXIF_RATIONAL,             # Longitude
 229                                 'GPSAltitudeRef' => MW_EXIF_BYTE,               # Altitude reference
 230                                 'GPSAltitude' => MW_EXIF_RATIONAL,              # Altitude
 231                                 'GPSTimeStamp' => MW_EXIF_RATIONAL,             # GPS time (atomic clock)
 232                                 'GPSSatellites' => MW_EXIF_ASCII,               # Satellites used for measurement
 233                                 'GPSStatus' => MW_EXIF_ASCII,                   # Receiver status #p54
 234                                 'GPSMeasureMode' => MW_EXIF_ASCII,              # Measurement mode #p54-55
 235                                 'GPSDOP' => MW_EXIF_RATIONAL,                   # Measurement precision
 236                                 'GPSSpeedRef' => MW_EXIF_ASCII,                 # Speed unit #p55
 237                                 'GPSSpeed' => MW_EXIF_RATIONAL,                 # Speed of GPS receiver
 238                                 'GPSTrackRef' => MW_EXIF_ASCII,                 # Reference for direction of movement #p55
 239                                 'GPSTrack' => MW_EXIF_RATIONAL,                 # Direction of movement
 240                                 'GPSImgDirectionRef' => MW_EXIF_ASCII,          # Reference for direction of image #p56
 241                                 'GPSImgDirection' => MW_EXIF_RATIONAL,          # Direction of image
 242                                 'GPSMapDatum' => MW_EXIF_ASCII,                 # Geodetic survey data used
 243                                 'GPSDestLatitudeRef' => MW_EXIF_ASCII,          # Reference for latitude of destination #p56
 244                                 'GPSDestLatitude' => MW_EXIF_RATIONAL,          # Latitude destination
 245                                 'GPSDestLongitudeRef' => MW_EXIF_ASCII,         # Reference for longitude of destination #p57
 246                                 'GPSDestLongitude' => MW_EXIF_RATIONAL,         # Longitude of destination
 247                                 'GPSDestBearingRef' => MW_EXIF_ASCII,           # Reference for bearing of destination #p57
 248                                 'GPSDestBearing' => MW_EXIF_RATIONAL,           # Bearing of destination
 249                                 'GPSDestDistanceRef' => MW_EXIF_ASCII,          # Reference for distance to destination #p57-58
 250                                 'GPSDestDistance' => MW_EXIF_RATIONAL,          # Distance to destination
 251                                 'GPSProcessingMethod' => MW_EXIF_UNDEFINED,     # Name of GPS processing method
 252                                 'GPSAreaInformation' => MW_EXIF_UNDEFINED,      # Name of GPS area
 253                                 'GPSDateStamp' => MW_EXIF_ASCII,                # GPS date
 254                                 'GPSDifferential' => MW_EXIF_SHORT,             # GPS differential correction
 255                         ),
 256                 );
 257
 258                 $this->makeFlatExifTags();
 259         }
 260
 261         /**
 262          * Generate a flat list of the exif tags
 263          */
 264         function makeFlatExifTags() {
 265                 $this->extractTags( $this->mExif );
 266         }
 267
 268         /**
 269          * A recursing extractor function used by makeFlatExifTags()
 270          *
 271          * Note: This used to use an array_walk function, but it made PHP5
 272          * segfault, see `cvs diff -u -r 1.4 -r 1.5 Exif.php`
 273          */
 274         function extractTags( $tagset ) {
 275                 foreach( $tagset as $key => $val ) {
 276                         if( is_array( $val ) ) {
 277                                 $this->extractTags( $val );
 278                         } else {
 279                                 $this->mFlatExif[$key] = $val;
 280                         }
 281                 }
 282         }
 283
 284          /**
 285           * The version of the output format
 286           *
 287           * Before the actual metadata information is saved in the database we
 288           * strip some of it since we don't want to save things like thumbnails
 289           * which usually accompany Exif data. This value gets saved in the
 290           * database along with the actual Exif data, and if the version in the
 291           * database doesn't equal the value returned by this function the Exif
 292           * data is regenerated.
 293           *
 294           * @return int
 295           */
 296         function version() {
 297                 return 1; // We don't need no bloddy constants!
 298         }
 299
 300         /**#@+
 301          * Validates if a tag value is of the type it should be according to the Exif spec
 302          *
 303          * @param mixed $in The input value to check
 304          * @return bool
 305          */
 306         function isByte( $in ) {
 307                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 255 ) {
 308                         $this->debug( $in, __FUNCTION__, true );
 309                         return true;
 310                 } else {
 311                         $this->debug( $in, __FUNCTION__, false );
 312                         return false;
 313                 }
 314         }
 315
 316         function isASCII( $in ) {
 317                 if ( preg_match( "/[^\x0a\x20-\x7e]/", $in ) ) {
 318                         $this->debug( $in, __FUNCTION__, 'found a character not in our whitelist' );
 319                         return false;
 320                 }
 321
 322                 if ( preg_match( "/^\s*$/", $in ) ) {
 323                         $this->debug( $in, __FUNCTION__, 'input consisted solely of whitespace' );
 324                         return false;
 325                 }
 326
 327                 if ( strlen($in) > 1024 ) { // TODO: This might not be according to the spec
 328                         $this->debug( $in, __FUNCTION__, 'input was too long' );
 329                         return false;
 330                 }
 331
 332                 return true;
 333         }
 334
 335         function isShort( $in ) {
 336                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 65536 ) {
 337                         $this->debug( $in, __FUNCTION__, true );
 338                         return true;
 339                 } else {
 340                         $this->debug( $in, __FUNCTION__, true );
 341                         return false;
 342                 }
 343         }
 344
 345         function isLong( $in ) {
 346                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 4294967296 ) {
 347                         $this->debug( $in, __FUNCTION__, true );
 348                         return true;
 349                 } else {
 350                         $this->debug( $in, __FUNCTION__, false );
 351                         return false;
 352                 }
 353         }
 354
 355         function isRational( $in ) {
 356                 if ( preg_match( "/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/", $in, $m ) ) { # Avoid division by zero
 357                         return $this->isLong( $m[1] ) && $this->isLong( $m[2] );
 358                 } else {
 359                         $this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
 360                         return false;
 361                 }
 362         }
 363
 364         function isUndefined( $in ) {
 365                 $this->debug( $in, __FUNCTION__ );
 366                 if ( preg_match( "/^\d{4}$/", $in ) ) { // Allow ExifVersion and FlashpixVersion
 367                         return true;
 368                 } else {
 369                         return false;
 370                 }
 371         }
 372
 373         function isSlong( $in ) {
 374                 if ( $this->isLong( abs( $in ) ) ) {
 375                         $this->debug( $in, __FUNCTION__, true );
 376                         return true;
 377                 } else {
 378                         $this->debug( $in, __FUNCTION__, false );
 379                         return false;
 380                 }
 381         }
 382
 383         function isSrational( $in ) {
 384                 if ( preg_match( "/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/", $in, $m ) ) { # Avoid division by zero
 385                         return $this->isSlong( $m[0] ) && $this->isSlong( $m[1] );
 386                 } else {
 387                         $this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
 388                         return false;
 389                 }
 390         }
 391         /**#@-*/
 392
 393         /**
 394          * Validates if a tag has a legal value according to the Exif spec
 395          *
 396          * @param string $tag The tag to check
 397          * @param mixed  $val The value of the tag
 398          * @return bool
 399          */
 400         function validate( $tag, $val ) {
 401                 // Fucks up if not typecast
 402                 switch( (string)$this->mFlatExif[$tag] ) {
 403                         case (string)MW_EXIF_BYTE:
 404                                 return $this->isByte( $val );
 405                         case (string)MW_EXIF_ASCII:
 406                                 return $this->isASCII( $val );
 407                         case (string)MW_EXIF_SHORT:
 408                                 return $this->isShort( $val );
 409                         case (string)MW_EXIF_LONG:
 410                                 return $this->isLong( $val );
 411                         case (string)MW_EXIF_RATIONAL:
 412                                 return $this->isRational( $val );
 413                         case (string)MW_EXIF_UNDEFINED:
 414                                 return $this->isUndefined( $val );
 415                         case (string)MW_EXIF_SLONG:
 416                                 return $this->isSlong( $val );
 417                         case (string)MW_EXIF_SRATIONAL:
 418                                 return $this->isSrational( $val );
 419                         case (string)MW_EXIF_SHORT.','.MW_EXIF_LONG:
 420                                 return $this->isShort( $val ) || $this->isLong( $val );
 421                         default:
 422                                 wfDebug( ucfirst( __CLASS__ ) . '::' . __FUNCTION__ .
 423                                         ": The tag '$tag' in unknown (type: " . gettype( $val ) . "; content: '$val')\n" );
 424                                 return false;
 425                 }
 426         }
 427
 428         /**
 429          * Numbers given by Exif user agents are often magical, that is they
 430          * should be replaced by a detailed explanation depending on their
 431          * value which most of the time are plain integers. This function
 432          * formats Exif values into human readable form.
 433          *
 434          * @param string $tag The tag to be formatted
 435          * @param mixed  $val The value of the tag
 436          * @return string
 437          */
 438         function format( $tag, $val ) {
 439                 global $wgLang;
 440
 441                 switch( $tag ) {
 442                 case 'Compression':
 443                         switch( $val ) {
 444                         case 1: case 6:
 445                                 return $this->msg( $tag, $val );
 446                         default:
 447                                 return $val;
 448                         }
 449
 450                 case 'PhotometricInterpretation':
 451                         switch( $val ) {
 452                         case 2: case 6:
 453                                 return $this->msg( $tag, $val );
 454                         default:
 455                                 return $val;
 456                         }
 457
 458                 case 'Orientation':
 459                         switch( $val ) {
 460                         case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 461                                 return $this->msg( $tag, $val );
 462                         default:
 463                                 return $val;
 464                         }
 465
 466                 case 'PlanarConfiguration':
 467                         switch( $val ) {
 468                         case 1: case 2:
 469                                 return $this->msg( $tag, $val );
 470                         default:
 471                                 return $val;
 472                         }
 473
 474                 // TODO: YCbCrSubSampling
 475                 // TODO: YCbCrPositioning
 476                 // TODO: If this field does not exists use 2
 477                 case 'ResolutionUnit': #p26
 478                         switch( $val ) {
 479                         case 2: case 3:
 480                                 return $this->msg( $tag, $val );
 481                         default:
 482                                 return $val;
 483                         }
 484
 485                 // TODO: YCbCrCoefficients  #p27 (see annex E)
 486                 case 'ExifVersion': case 'FlashpixVersion':
 487                         return "$val"/100;
 488
 489                 case 'ColorSpace':
 490                         switch( $val ) {
 491                         case 1: case 'FFFF.H':
 492                                 return $this->msg( $tag, $val );
 493                         default:
 494                                 return $val;
 495                         }
 496
 497                 case 'ComponentsConfiguration':
 498                         switch( $val ) {
 499                         case 0: case 1: case 2: case 3: case 4: case 5: case 6:
 500                                 return $this->msg( $tag, $val );
 501                         default:
 502                                 return $val;
 503                         }
 504
 505                 case 'DateTime':
 506                 case 'DateTimeOriginal':
 507                 case 'DateTimeDigitized':
 508                         return $wgLang->timeanddate( wfTimestamp(TS_MW, $val) );
 509
 510                 case 'ExposureProgram':
 511                         switch( $val ) {
 512                         case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 513                                 return $this->msg( $tag, $val );
 514                         default:
 515                                 return $val;
 516                         }
 517
 518                 case 'MeteringMode':
 519                         switch( $val ) {
 520                         case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 255:
 521                                 return $this->msg( $tag, $val );
 522                         default:
 523                                 return $val;
 524                         }
 525
 526                 case 'LightSource':
 527                         switch( $val ) {
 528                         case 0: case 1: case 2: case 3: case 4: case 9: case 10: case 11:
 529                         case 12: case 13: case 14: case 15: case 17: case 18: case 19: case 20:
 530                         case 21: case 22: case 23: case 24: case 255:
 531                                 return $this->msg( $tag, $val );
 532                         default:
 533                                 return $val;
 534                         }
 535
 536                 // TODO: Flash
 537                 case 'SensingMethod':
 538                         switch( $val ) {
 539                         case 1: case 2: case 3: case 4: case 5: case 7: case 8:
 540                                 return $this->msg( $tag, $val );
 541                         default:
 542                                 return $val;
 543                         }
 544
 545                 case 'FileSource':
 546                         switch( $val ) {
 547                         case 3:
 548                                 return $this->msg( $tag, $val );
 549                         default:
 550                                 return $val;
 551                         }
 552
 553                 case 'SceneType':
 554                         switch( $val ) {
 555                         case 1:
 556                                 return $this->msg( $tag, $val );
 557                         default:
 558                                 return $val;
 559                         }
 560
 561                 case 'CustomRendered':
 562                         switch( $val ) {
 563                         case 0: case 1:
 564                                 return $this->msg( $tag, $val );
 565                         default:
 566                                 return $val;
 567                         }
 568
 569                 case 'ExposureMode':
 570                         switch( $val ) {
 571                         case 0: case 1: case 2:
 572                                 return $this->msg( $tag, $val );
 573                         default:
 574                                 return $val;
 575                         }
 576
 577                 case 'WhiteBalance':
 578                         switch( $val ) {
 579                         case 0: case 1:
 580                                 return $this->msg( $tag, $val );
 581                         default:
 582                                 return $val;
 583                         }
 584
 585                 case 'SceneCaptureType':
 586                         switch( $val ) {
 587                         case 0: case 1: case 2: case 3:
 588                                 return $this->msg( $tag, $val );
 589                         default:
 590                                 return $val;
 591                         }
 592
 593                 case 'GainControl':
 594                         switch( $val ) {
 595                         case 0: case 1: case 2: case 3: case 4:
 596                                 return $this->msg( $tag, $val );
 597                         default:
 598                                 return $val;
 599                         }
 600
 601                 case 'Contrast':
 602                         switch( $val ) {
 603                         case 0: case 1: case 2:
 604                                 return $this->msg( $tag, $val );
 605                         default:
 606                                 return $val;
 607                         }
 608
 609                 case 'Saturation':
 610                         switch( $val ) {
 611                         case 0: case 1: case 2:
 612                                 return $this->msg( $tag, $val );
 613                         default:
 614                                 return $val;
 615                         }
 616
 617                 case 'Sharpness':
 618                         switch( $val ) {
 619                         case 0: case 1: case 2:
 620                                 return $this->msg( $tag, $val );
 621                         default:
 622                                 return $val;
 623                         }
 624
 625                 case 'SubjectDistanceRange':
 626                         switch( $val ) {
 627                         case 0: case 1: case 2: case 3:
 628                                 return $this->msg( $tag, $val );
 629                         default:
 630                                 return $val;
 631                         }
 632
 633                 case 'GPSLatitudeRef':
 634                 case 'GPSDestLatitudeRef':
 635                         switch( $val ) {
 636                         case 'N': case 'S':
 637                                 return $this->msg( 'GPSLatitude', $val );
 638                         default:
 639                                 return $val;
 640                         }
 641
 642                 case 'GPSLongitudeRef':
 643                 case 'GPSDestLongitudeRef':
 644                         switch( $val ) {
 645                         case 'E': case 'W':
 646                                 return $this->msg( 'GPSLongitude', $val );
 647                         default:
 648                                 return $val;
 649                         }
 650
 651                 case 'GPSStatus':
 652                         switch( $val ) {
 653                         case 'A': case 'V':
 654                                 return $this->msg( $tag, $val );
 655                         default:
 656                                 return $val;
 657                         }
 658
 659                 case 'GPSMeasureMode':
 660                         switch( $val ) {
 661                         case 2: case 3:
 662                                 return $this->msg( $tag, $val );
 663                         default:
 664                                 return $val;
 665                         }
 666
 667                 case 'GPSSpeedRef':
 668                 case 'GPSDestDistanceRef':
 669                         switch( $val ) {
 670                         case 'K': case 'M': case 'N':
 671                                 return $this->msg( 'GPSSpeed', $val );
 672                         default:
 673                                 return $val;
 674                         }
 675
 676                 case 'GPSTrackRef':
 677                 case 'GPSImgDirectionRef':
 678                 case 'GPSDestBearingRef':
 679                         switch( $val ) {
 680                         case 'T': case 'M':
 681                                 return $this->msg( 'GPSDirection', $val );
 682                         default:
 683                                 return $val;
 684                         }
 685
 686                 case 'GPSDateStamp':
 687                         return $wgLang->date( substr( $val, 0, 4 ) . substr( $val, 5, 2 ) . substr( $val, 8, 2 ) . '000000' );
 688
 689                 // This is not in the Exif standard, just a special
 690                 // case for our purposes which enables wikis to wikify
 691                 // the make, model and software name to link to their articles.
 692                 case 'Make':
 693                 case 'Model':
 694                 case 'Software':
 695                         return wfMsg( strtolower( "exif-$tag-value" ), $val );
 696                 default:
 697                         if ( preg_match( '/^(\d+)\/(\d+)$/', $val, $m ) ) {
 698                                 return $m[2] != 0 ? $m[1]/$m[2] : $val;
 699                         }
 700                         return $val;
 701                 }
 702         }
 703
 704         /**
 705          * Conviniance function for format()
 706          *
 707          * @param string $tag The tag name to pass on
 708          * @param string $val The value of the tag
 709          * @return string A wfMsg of "exif-$tag-$val" in lower case
 710          */
 711         function msg( $tag, $val ) {
 712                 return wfMsg( strtolower("exif-$tag-$val") );
 713         }
 714
 715         /**
 716          * Conviniance function for debugging output
 717          *
 718          * @param mixed $in
 719          * @param string $fname
 720          * @param mixed $action
 721          */
 722          function debug( $in, $fname, $action = null ) {
 723                 $type = gettype( $in );
 724                 $class = ucfirst( __CLASS__ );
 725                 if ( $type === 'array' )
 726                         $in = print_r( $in, true );
 727
 728                 if ( $action === true )
 729                         wfDebug( "$class::$fname: accepted: '$in' (type: $type)\n");
 730                 elseif ( $action === false )
 731                         wfDebug( "$class::$fname: rejected: '$in' (type: $type)\n");
 732                 elseif ( $action === null )
 733                         wfDebug( "$class::$fname: input was: '$in' (type: $type)\n");
 734                 else
 735                         wfDebug( "$class::$fname: $action (type: $type; content: '$in')\n");
 736          }
 737 }
 738
 739 } // MEDIAWIKI