summaryrefslogtreecommitdiff
path: root/includes/Exif.php
blob: 9e54bd551042a31215dfd869517cbd90d41b0e88 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @ingroup Media
 * @author Ævar Arnfjörð Bjarmason <avarab@gmail.com>
 * @copyright Copyright © 2005, Ævar Arnfjörð Bjarmason
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
 * @see http://exif.org/Exif2-2.PDF The Exif 2.2 specification
 * @file
 */

/**
 * @todo document (e.g. one-sentence class-overview description)
 * @ingroup Media
 */
class Exif {

	const BYTE      = 1;    //!< An 8-bit (1-byte) unsigned integer.
	const ASCII     = 2;    //!< An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
	const SHORT     = 3;    //!< A 16-bit (2-byte) unsigned integer.
	const LONG      = 4;    //!< A 32-bit (4-byte) unsigned integer.
	const RATIONAL  = 5;    //!< Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
	const UNDEFINED = 7;    //!< An 8-bit byte that can take any value depending on the field definition
	const SLONG     = 9;    //!< A 32-bit (4-byte) signed integer (2's complement notation),
	const SRATIONAL = 10;   //!< Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.

	//@{
	/* @var array
	 * @private
	 */

	/**
	 * Exif tags grouped by category, the tagname itself is the key and the type
	 * is the value, in the case of more than one possible value type they are
	 * separated by commas.
	 */
	var $mExifTags;

	/**
	 * A one dimentional array of all Exif tags
	 */
	var $mFlatExifTags;

	/**
	 * The raw Exif data returned by exif_read_data()
	 */
	var $mRawExifData;

	/**
	 * A Filtered version of $mRawExifData that has been pruned of invalid
	 * tags and tags that contain content they shouldn't contain according
	 * to the Exif specification
	 */
	var $mFilteredExifData;

	/**
	 * Filtered and formatted Exif data, see FormatExif::getFormattedData()
	 */
	var $mFormattedExifData;

	//@}

	//@{
	/* @var string
	 * @private
	 */

	/**
	 * The file being processed
	 */
	var $file;

	/**
	 * The basename of the file being processed
	 */
	var $basename;

	/**
	 * The private log to log to, e.g. 'exif'
	 */
	var $log = false;

	//@}

	/**
	 * Constructor
	 *
	 * @param $file String: filename.
	 */
	function __construct( $file ) {
		/**
		 * Page numbers here refer to pages in the EXIF 2.2 standard
		 *
		 * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
		 */
		$this->mExifTags = array(
			# TIFF Rev. 6.0 Attribute Information (p22)
			'tiff' => array(
				# Tags relating to image structure
				'structure' => array(
					'ImageWidth' => Exif::SHORT.','.Exif::LONG,		# Image width
					'ImageLength' => Exif::SHORT.','.Exif::LONG,	# Image height
					'BitsPerSample' => Exif::SHORT,			# Number of bits per component
					# "When a primary image is JPEG compressed, this designation is not"
					# "necessary and is omitted." (p23)
					'Compression' => Exif::SHORT,				# Compression scheme #p23
					'PhotometricInterpretation' => Exif::SHORT,		# Pixel composition #p23
					'Orientation' => Exif::SHORT,				# Orientation of image #p24
					'SamplesPerPixel' => Exif::SHORT,			# Number of components
					'PlanarConfiguration' => Exif::SHORT,			# Image data arrangement #p24
					'YCbCrSubSampling' => Exif::SHORT,			# Subsampling ratio of Y to C #p24
					'YCbCrPositioning' => Exif::SHORT,			# Y and C positioning #p24-25
					'XResolution' => Exif::RATIONAL,			# Image resolution in width direction
					'YResolution' => Exif::RATIONAL,			# Image resolution in height direction
					'ResolutionUnit' => Exif::SHORT,			# Unit of X and Y resolution #(p26)
				),

				# Tags relating to recording offset
				'offset' => array(
					'StripOffsets' => Exif::SHORT.','.Exif::LONG,			# Image data location
					'RowsPerStrip' => Exif::SHORT.','.Exif::LONG,			# Number of rows per strip
					'StripByteCounts' => Exif::SHORT.','.Exif::LONG,			# Bytes per compressed strip
					'JPEGInterchangeFormat' => Exif::SHORT.','.Exif::LONG,		# Offset to JPEG SOI
					'JPEGInterchangeFormatLength' => Exif::SHORT.','.Exif::LONG,	# Bytes of JPEG data
				),

				# Tags relating to image data characteristics
				'characteristics' => array(
					'TransferFunction' => Exif::SHORT,		# Transfer function
					'WhitePoint' => Exif::RATIONAL,		# White point chromaticity
					'PrimaryChromaticities' => Exif::RATIONAL,	# Chromaticities of primarities
					'YCbCrCoefficients' => Exif::RATIONAL,	# Color space transformation matrix coefficients #p27
					'ReferenceBlackWhite' => Exif::RATIONAL	# Pair of black and white reference values
				),

				# Other tags
				'other' => array(
					'DateTime' => Exif::ASCII,            # File change date and time
					'ImageDescription' => Exif::ASCII,    # Image title
					'Make' => Exif::ASCII,                # Image input equipment manufacturer
					'Model' => Exif::ASCII,               # Image input equipment model
					'Software' => Exif::ASCII,            # Software used
					'Artist' => Exif::ASCII,              # Person who created the image
					'Copyright' => Exif::ASCII,           # Copyright holder
				),
			),

			# Exif IFD Attribute Information (p30-31)
			'exif' => array(
				# Tags relating to version
				'version' => array(
					# TODO: NOTE: Nonexistence of this field is taken to mean nonconformance
					# to the EXIF 2.1 AND 2.2 standards
					'ExifVersion' => Exif::UNDEFINED,	# Exif version
					'FlashpixVersion' => Exif::UNDEFINED, # Supported Flashpix version #p32
				),

				# Tags relating to Image Data Characteristics
				'characteristics' => array(
					'ColorSpace' => Exif::SHORT,		# Color space information #p32
				),

				# Tags relating to image configuration
				'configuration' => array(
					'ComponentsConfiguration' => Exif::UNDEFINED,		# Meaning of each component #p33
					'CompressedBitsPerPixel' => Exif::RATIONAL,		# Image compression mode
					'PixelYDimension' => Exif::SHORT.','.Exif::LONG,	# Valid image width
					'PixelXDimension' => Exif::SHORT.','.Exif::LONG,	# Valind image height
				),

				# Tags relating to related user information
				'user' => array(
					'MakerNote' => Exif::UNDEFINED,			# Manufacturer notes
					'UserComment' => Exif::UNDEFINED,			# User comments #p34
				),

				# Tags relating to related file information
				'related' => array(
					'RelatedSoundFile' => Exif::ASCII,			# Related audio file
				),

				# Tags relating to date and time
				'dateandtime' => array(
					'DateTimeOriginal' => Exif::ASCII,			# Date and time of original data generation #p36
					'DateTimeDigitized' => Exif::ASCII,			# Date and time of original data generation
					'SubSecTime' => Exif::ASCII,				# DateTime subseconds
					'SubSecTimeOriginal' => Exif::ASCII,			# DateTimeOriginal subseconds
					'SubSecTimeDigitized' => Exif::ASCII,			# DateTimeDigitized subseconds
				),

				# Tags relating to picture-taking conditions (p31)
				'conditions' => array(
					'ExposureTime' => Exif::RATIONAL,			# Exposure time
					'FNumber' => Exif::RATIONAL,				# F Number
					'ExposureProgram' => Exif::SHORT,			# Exposure Program #p38
					'SpectralSensitivity' => Exif::ASCII,			# Spectral sensitivity
					'ISOSpeedRatings' => Exif::SHORT,			# ISO speed rating
					'OECF' => Exif::UNDEFINED,				# Optoelectronic conversion factor
					'ShutterSpeedValue' => Exif::SRATIONAL,		# Shutter speed
					'ApertureValue' => Exif::RATIONAL,			# Aperture
					'BrightnessValue' => Exif::SRATIONAL,			# Brightness
					'ExposureBiasValue' => Exif::SRATIONAL,		# Exposure bias
					'MaxApertureValue' => Exif::RATIONAL,			# Maximum land aperture
					'SubjectDistance' => Exif::RATIONAL,			# Subject distance
					'MeteringMode' => Exif::SHORT,			# Metering mode #p40
					'LightSource' => Exif::SHORT,				# Light source #p40-41
					'Flash' => Exif::SHORT,				# Flash #p41-42
					'FocalLength' => Exif::RATIONAL,			# Lens focal length
					'SubjectArea' => Exif::SHORT,				# Subject area
					'FlashEnergy' => Exif::RATIONAL,			# Flash energy
					'SpatialFrequencyResponse' => Exif::UNDEFINED,	# Spatial frequency response
					'FocalPlaneXResolution' => Exif::RATIONAL,		# Focal plane X resolution
					'FocalPlaneYResolution' => Exif::RATIONAL,		# Focal plane Y resolution
					'FocalPlaneResolutionUnit' => Exif::SHORT,		# Focal plane resolution unit #p46
					'SubjectLocation' => Exif::SHORT,			# Subject location
					'ExposureIndex' => Exif::RATIONAL,			# Exposure index
					'SensingMethod' => Exif::SHORT,			# Sensing method #p46
					'FileSource' => Exif::UNDEFINED,			# File source #p47
					'SceneType' => Exif::UNDEFINED,			# Scene type #p47
					'CFAPattern' => Exif::UNDEFINED,			# CFA pattern
					'CustomRendered' => Exif::SHORT,			# Custom image processing #p48
					'ExposureMode' => Exif::SHORT,			# Exposure mode #p48
					'WhiteBalance' => Exif::SHORT,			# White Balance #p49
					'DigitalZoomRatio' => Exif::RATIONAL,			# Digital zoom ration
					'FocalLengthIn35mmFilm' => Exif::SHORT,		# Focal length in 35 mm film
					'SceneCaptureType' => Exif::SHORT,			# Scene capture type #p49
					'GainControl' => Exif::RATIONAL,			# Scene control #p49-50
					'Contrast' => Exif::SHORT,				# Contrast #p50
					'Saturation' => Exif::SHORT,				# Saturation #p50
					'Sharpness' => Exif::SHORT,				# Sharpness #p50
					'DeviceSettingDescription' => Exif::UNDEFINED,	# Desice settings description
					'SubjectDistanceRange' => Exif::SHORT,		# Subject distance range #p51
				),

				'other' => array(
					'ImageUniqueID' => Exif::ASCII,	# Unique image ID
				),
			),

			# GPS Attribute Information (p52)
			'gps' => array(
				'GPSVersionID' => Exif::BYTE,			# GPS tag version
				'GPSLatitudeRef' => Exif::ASCII,		# North or South Latitude #p52-53
				'GPSLatitude' => Exif::RATIONAL,		# Latitude
				'GPSLongitudeRef' => Exif::ASCII,		# East or West Longitude #p53
				'GPSLongitude' => Exif::RATIONAL,		# Longitude
				'GPSAltitudeRef' => Exif::BYTE,		# Altitude reference
				'GPSAltitude' => Exif::RATIONAL,		# Altitude
				'GPSTimeStamp' => Exif::RATIONAL,		# GPS time (atomic clock)
				'GPSSatellites' => Exif::ASCII,		# Satellites used for measurement
				'GPSStatus' => Exif::ASCII,			# Receiver status #p54
				'GPSMeasureMode' => Exif::ASCII,		# Measurement mode #p54-55
				'GPSDOP' => Exif::RATIONAL,			# Measurement precision
				'GPSSpeedRef' => Exif::ASCII,			# Speed unit #p55
				'GPSSpeed' => Exif::RATIONAL,			# Speed of GPS receiver
				'GPSTrackRef' => Exif::ASCII,			# Reference for direction of movement #p55
				'GPSTrack' => Exif::RATIONAL,			# Direction of movement
				'GPSImgDirectionRef' => Exif::ASCII,		# Reference for direction of image #p56
				'GPSImgDirection' => Exif::RATIONAL,		# Direction of image
				'GPSMapDatum' => Exif::ASCII,			# Geodetic survey data used
				'GPSDestLatitudeRef' => Exif::ASCII,		# Reference for latitude of destination #p56
				'GPSDestLatitude' => Exif::RATIONAL,		# Latitude destination
				'GPSDestLongitudeRef' => Exif::ASCII,		# Reference for longitude of destination #p57
				'GPSDestLongitude' => Exif::RATIONAL,		# Longitude of destination
				'GPSDestBearingRef' => Exif::ASCII,		# Reference for bearing of destination #p57
				'GPSDestBearing' => Exif::RATIONAL,		# Bearing of destination
				'GPSDestDistanceRef' => Exif::ASCII,		# Reference for distance to destination #p57-58
				'GPSDestDistance' => Exif::RATIONAL,		# Distance to destination
				'GPSProcessingMethod' => Exif::UNDEFINED,	# Name of GPS processing method
				'GPSAreaInformation' => Exif::UNDEFINED,	# Name of GPS area
				'GPSDateStamp' => Exif::ASCII,		# GPS date
				'GPSDifferential' => Exif::SHORT,		# GPS differential correction
			),
		);

		$this->file = $file;
		$this->basename = wfBaseName( $this->file );

		$this->makeFlatExifTags();

		$this->debugFile( $this->basename, __FUNCTION__, true );
		wfSuppressWarnings();
		$data = exif_read_data( $this->file );
		wfRestoreWarnings();
		/**
		 * exif_read_data() will return false on invalid input, such as
		 * when somebody uploads a file called something.jpeg
		 * containing random gibberish.
		 */
		$this->mRawExifData = $data ? $data : array();

		$this->makeFilteredData();
		$this->makeFormattedData();

		$this->debugFile( __FUNCTION__, false );
	}

	/**#@+
	 * @private
	 */
	/**
	 * Generate a flat list of the exif tags
	 */
	function makeFlatExifTags() {
		$this->extractTags( $this->mExifTags );
	}

	/**
	 * A recursing extractor function used by makeFlatExifTags()
	 *
	 * Note: This used to use an array_walk function, but it made PHP5
	 * segfault, see `cvs diff -u -r 1.4 -r 1.5 Exif.php`
	 */
	function extractTags( &$tagset ) {
		foreach( $tagset as $key => $val ) {
			if( is_array( $val ) ) {
				$this->extractTags( $val );
			} else {
				$this->mFlatExifTags[$key] = $val;
			}
		}
	}

	/**
	 * Make $this->mFilteredExifData
	 */
	function makeFilteredData() {
		$this->mFilteredExifData = $this->mRawExifData;

		foreach( $this->mFilteredExifData as $k => $v ) {
			if ( !in_array( $k, array_keys( $this->mFlatExifTags ) ) ) {
				$this->debug( $v, __FUNCTION__, "'$k' is not a valid Exif tag" );
				unset( $this->mFilteredExifData[$k] );
			}
		}

		foreach( $this->mFilteredExifData as $k => $v ) {
			if ( !$this->validate($k, $v) ) {
				$this->debug( $v, __FUNCTION__, "'$k' contained invalid data" );
				unset( $this->mFilteredExifData[$k] );
			}
		}
	}

	/**
	 * @todo document
	 */
	function makeFormattedData( ) {
		$format = new FormatExif( $this->getFilteredData() );
		$this->mFormattedExifData = $format->getFormattedData();
	}
	/**#@-*/

	/**#@+
	 * @return array
	 */
	/**
	 * Get $this->mRawExifData
	 */
	function getData() {
		return $this->mRawExifData;
	}

	/**
	 * Get $this->mFilteredExifData
	 */
	function getFilteredData() {
		return $this->mFilteredExifData;
	}

	/**
	 * Get $this->mFormattedExifData
	 */
	function getFormattedData() {
		return $this->mFormattedExifData;
	}
	/**#@-*/

	/**
	 * The version of the output format
	 *
	 * Before the actual metadata information is saved in the database we
	 * strip some of it since we don't want to save things like thumbnails
	 * which usually accompany Exif data. This value gets saved in the
	 * database along with the actual Exif data, and if the version in the
	 * database doesn't equal the value returned by this function the Exif
	 * data is regenerated.
	 *
	 * @return int
	 */
	public static function version() {
		return 1; // We don't need no bloddy constants!
	}

	/**#@+
	 * Validates if a tag value is of the type it should be according to the Exif spec
	 *
	 * @private
	 *
	 * @param $in Mixed: the input value to check
	 * @return bool
	 */
	function isByte( $in ) {
		if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 255 ) {
			$this->debug( $in, __FUNCTION__, true );
			return true;
		} else {
			$this->debug( $in, __FUNCTION__, false );
			return false;
		}
	}

	function isASCII( $in ) {
		if ( is_array( $in ) ) {
			return false;
		}

		if ( preg_match( "/[^\x0a\x20-\x7e]/", $in ) ) {
			$this->debug( $in, __FUNCTION__, 'found a character not in our whitelist' );
			return false;
		}

		if ( preg_match( '/^\s*$/', $in ) ) {
			$this->debug( $in, __FUNCTION__, 'input consisted solely of whitespace' );
			return false;
		}

		return true;
	}

	function isShort( $in ) {
		if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 65536 ) {
			$this->debug( $in, __FUNCTION__, true );
			return true;
		} else {
			$this->debug( $in, __FUNCTION__, false );
			return false;
		}
	}

	function isLong( $in ) {
		if ( !is_array( $in ) && sprintf('%d', $in) == $in && $in >= 0 && $in <= 4294967296 ) {
			$this->debug( $in, __FUNCTION__, true );
			return true;
		} else {
			$this->debug( $in, __FUNCTION__, false );
			return false;
		}
	}

	function isRational( $in ) {
		$m = array();
		if ( !is_array( $in ) && @preg_match( '/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/', $in, $m ) ) { # Avoid division by zero
			return $this->isLong( $m[1] ) && $this->isLong( $m[2] );
		} else {
			$this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
			return false;
		}
	}

	function isUndefined( $in ) {
		if ( !is_array( $in ) && preg_match( '/^\d{4}$/', $in ) ) { // Allow ExifVersion and FlashpixVersion
			$this->debug( $in, __FUNCTION__, true );
			return true;
		} else {
			$this->debug( $in, __FUNCTION__, false );
			return false;
		}
	}

	function isSlong( $in ) {
		if ( $this->isLong( abs( $in ) ) ) {
			$this->debug( $in, __FUNCTION__, true );
			return true;
		} else {
			$this->debug( $in, __FUNCTION__, false );
			return false;
		}
	}

	function isSrational( $in ) {
		$m = array();
		if ( !is_array( $in ) && preg_match( '/^(\d+)\/(\d+[1-9]|[1-9]\d*)$/', $in, $m ) ) { # Avoid division by zero
			return $this->isSlong( $m[0] ) && $this->isSlong( $m[1] );
		} else {
			$this->debug( $in, __FUNCTION__, 'fed a non-fraction value' );
			return false;
		}
	}
	/**#@-*/

	/**
	 * Validates if a tag has a legal value according to the Exif spec
	 *
	 * @private
	 *
	 * @param $tag String: the tag to check.
	 * @param $val Mixed: the value of the tag.
	 * @return bool
	 */
	function validate( $tag, $val ) {
		$debug = "tag is '$tag'";
		// Does not work if not typecast
		switch( (string)$this->mFlatExifTags[$tag] ) {
			case (string)Exif::BYTE:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isByte( $val );
			case (string)Exif::ASCII:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isASCII( $val );
			case (string)Exif::SHORT:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isShort( $val );
			case (string)Exif::LONG:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isLong( $val );
			case (string)Exif::RATIONAL:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isRational( $val );
			case (string)Exif::UNDEFINED:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isUndefined( $val );
			case (string)Exif::SLONG:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isSlong( $val );
			case (string)Exif::SRATIONAL:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isSrational( $val );
			case (string)Exif::SHORT.','.Exif::LONG:
				$this->debug( $val, __FUNCTION__, $debug );
				return $this->isShort( $val ) || $this->isLong( $val );
			default:
				$this->debug( $val, __FUNCTION__, "The tag '$tag' is unknown" );
				return false;
		}
	}

	/**
	 * Convenience function for debugging output
	 *
	 * @private
	 *
	 * @param $in Mixed:
	 * @param $fname String:
	 * @param $action Mixed: , default NULL.
	 */
	function debug( $in, $fname, $action = NULL ) {
		if ( !$this->log ) {
			return;
		}
		$type = gettype( $in );
		$class = ucfirst( __CLASS__ );
		if ( $type === 'array' )
			$in = print_r( $in, true );

		if ( $action === true )
			wfDebugLog( $this->log, "$class::$fname: accepted: '$in' (type: $type)\n");
		elseif ( $action === false )
			wfDebugLog( $this->log, "$class::$fname: rejected: '$in' (type: $type)\n");
		elseif ( $action === null )
			wfDebugLog( $this->log, "$class::$fname: input was: '$in' (type: $type)\n");
		else
			wfDebugLog( $this->log, "$class::$fname: $action (type: $type; content: '$in')\n");
	}

	/**
	 * Convenience function for debugging output
	 *
	 * @private
	 *
	 * @param $fname String: the name of the function calling this function
	 * @param $io Boolean: Specify whether we're beginning or ending
	 */
	function debugFile( $fname, $io ) {
		if ( !$this->log ) {
			return;
		}
		$class = ucfirst( __CLASS__ );
		if ( $io ) {
			wfDebugLog( $this->log, "$class::$fname: begin processing: '{$this->basename}'\n" );
		} else {
			wfDebugLog( $this->log, "$class::$fname: end processing: '{$this->basename}'\n" );
		}
	}

}

/**
 * @todo document (e.g. one-sentence class-overview description)
 * @ingroup Media
 */
class FormatExif {
	/**
	 * The Exif data to format
	 *
	 * @var array
	 * @private
	 */
	var $mExif;

	/**
	 * Constructor
	 *
	 * @param $exif Array: the Exif data to format ( as returned by
	 *                    Exif::getFilteredData() )
	 */
	function FormatExif( $exif ) {
		$this->mExif = $exif;
	}

	/**
	 * Numbers given by Exif user agents are often magical, that is they
	 * should be replaced by a detailed explanation depending on their
	 * value which most of the time are plain integers. This function
	 * formats Exif values into human readable form.
	 *
	 * @return array
	 */
	function getFormattedData() {
		global $wgLang;

		$tags =& $this->mExif;

		$resolutionunit = !isset( $tags['ResolutionUnit'] ) || $tags['ResolutionUnit'] == 2 ? 2 : 3;
		unset( $tags['ResolutionUnit'] );

		foreach( $tags as $tag => $val ) {
			switch( $tag ) {
			case 'Compression':
				switch( $val ) {
				case 1: case 6:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'PhotometricInterpretation':
				switch( $val ) {
				case 2: case 6:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'Orientation':
				switch( $val ) {
				case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'PlanarConfiguration':
				switch( $val ) {
				case 1: case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			// TODO: YCbCrSubSampling
			// TODO: YCbCrPositioning

			case 'XResolution':
			case 'YResolution':
				switch( $resolutionunit ) {
					case 2:
						$tags[$tag] = $this->msg( 'XYResolution', 'i', $this->formatNum( $val ) );
						break;
					case 3:
						$this->msg( 'XYResolution', 'c', $this->formatNum( $val ) );
						break;
					default:
						$tags[$tag] = $val;
						break;
				}
				break;

			// TODO: YCbCrCoefficients  #p27 (see annex E)
			case 'ExifVersion': case 'FlashpixVersion':
				$tags[$tag] = "$val"/100;
				break;

			case 'ColorSpace':
				switch( $val ) {
				case 1: case 'FFFF.H':
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'ComponentsConfiguration':
				switch( $val ) {
				case 0: case 1: case 2: case 3: case 4: case 5: case 6:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'DateTime':
			case 'DateTimeOriginal':
			case 'DateTimeDigitized':
				if( $val == '0000:00:00 00:00:00' ) {
					$tags[$tag] = wfMsg('exif-unknowndate');
				} elseif( preg_match( '/^(?:\d{4}):(?:\d\d):(?:\d\d) (?:\d\d):(?:\d\d):(?:\d\d)$/', $val ) ) {
					$tags[$tag] = $wgLang->timeanddate( wfTimestamp(TS_MW, $val) );
				}
				break;

			case 'ExposureProgram':
				switch( $val ) {
				case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'SubjectDistance':
				$tags[$tag] = $this->msg( $tag, '', $this->formatNum( $val ) );
				break;

			case 'MeteringMode':
				switch( $val ) {
				case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 255:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'LightSource':
				switch( $val ) {
				case 0: case 1: case 2: case 3: case 4: case 9: case 10: case 11:
				case 12: case 13: case 14: case 15: case 17: case 18: case 19: case 20:
				case 21: case 22: case 23: case 24: case 255:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'Flash':
				$flashDecode = array(
					'fired'    => $val & bindec( '00000001' ),
					'return'   => ($val & bindec( '00000110' )) >> 1,
					'mode'     => ($val & bindec( '00011000' )) >> 3,
					'function' => ($val & bindec( '00100000' )) >> 5,
					'redeye'   => ($val & bindec( '01000000' )) >> 6,
//					'reserved' => ($val & bindec( '10000000' )) >> 7,
				);

				# We do not need to handle unknown values since all are used.
				foreach( $flashDecode as $subTag => $subValue ) {
					# We do not need any message for zeroed values.
					if( $subTag != 'fired' && $subValue == 0) {
						continue;
					}
					$fullTag = $tag . '-' . $subTag ;
					$flashMsgs[] = $this->msg( $fullTag, $subValue );
				}
				$tags[$tag] = $wgLang->commaList( $flashMsgs );
			break;

			case 'FocalPlaneResolutionUnit':
				switch( $val ) {
				case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'SensingMethod':
				switch( $val ) {
				case 1: case 2: case 3: case 4: case 5: case 7: case 8:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'FileSource':
				switch( $val ) {
				case 3:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'SceneType':
				switch( $val ) {
				case 1:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'CustomRendered':
				switch( $val ) {
				case 0: case 1:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'ExposureMode':
				switch( $val ) {
				case 0: case 1: case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'WhiteBalance':
				switch( $val ) {
				case 0: case 1:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'SceneCaptureType':
				switch( $val ) {
				case 0: case 1: case 2: case 3:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GainControl':
				switch( $val ) {
				case 0: case 1: case 2: case 3: case 4:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'Contrast':
				switch( $val ) {
				case 0: case 1: case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'Saturation':
				switch( $val ) {
				case 0: case 1: case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'Sharpness':
				switch( $val ) {
				case 0: case 1: case 2:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'SubjectDistanceRange':
				switch( $val ) {
				case 0: case 1: case 2: case 3:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSLatitudeRef':
			case 'GPSDestLatitudeRef':
				switch( $val ) {
				case 'N': case 'S':
					$tags[$tag] = $this->msg( 'GPSLatitude', $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSLongitudeRef':
			case 'GPSDestLongitudeRef':
				switch( $val ) {
				case 'E': case 'W':
					$tags[$tag] = $this->msg( 'GPSLongitude', $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSStatus':
				switch( $val ) {
				case 'A': case 'V':
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSMeasureMode':
				switch( $val ) {
				case 2: case 3:
					$tags[$tag] = $this->msg( $tag, $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSSpeedRef':
			case 'GPSDestDistanceRef':
				switch( $val ) {
				case 'K': case 'M': case 'N':
					$tags[$tag] = $this->msg( 'GPSSpeed', $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSTrackRef':
			case 'GPSImgDirectionRef':
			case 'GPSDestBearingRef':
				switch( $val ) {
				case 'T': case 'M':
					$tags[$tag] = $this->msg( 'GPSDirection', $val );
					break;
				default:
					$tags[$tag] = $val;
					break;
				}
				break;

			case 'GPSDateStamp':
				$tags[$tag] = $wgLang->date( substr( $val, 0, 4 ) . substr( $val, 5, 2 ) . substr( $val, 8, 2 ) . '000000' );
				break;

			// This is not in the Exif standard, just a special
			// case for our purposes which enables wikis to wikify
			// the make, model and software name to link to their articles.
			case 'Make':
			case 'Model':
			case 'Software':
				$tags[$tag] = $this->msg( $tag, '', $val );
				break;

			case 'ExposureTime':
				// Show the pretty fraction as well as decimal version
				$tags[$tag] = wfMsg( 'exif-exposuretime-format',
					$this->formatFraction( $val ), $this->formatNum( $val ) );
				break;

			case 'FNumber':
				$tags[$tag] = wfMsg( 'exif-fnumber-format',
					$this->formatNum( $val ) );
				break;

			case 'FocalLength':
				$tags[$tag] = wfMsg( 'exif-focallength-format',
					$this->formatNum( $val ) );
				break;

			default:
				$tags[$tag] = $this->formatNum( $val );
				break;
			}
		}

		return $tags;
	}

	/**
	 * Convenience function for getFormattedData()
	 *
	 * @private
	 *
	 * @param $tag String: the tag name to pass on
	 * @param $val String: the value of the tag
	 * @param $arg String: an argument to pass ($1)
	 * @return string A wfMsg of "exif-$tag-$val" in lower case
	 */
	function msg( $tag, $val, $arg = null ) {
		global $wgContLang;

		if ($val === '')
			$val = 'value';
		return wfMsg( $wgContLang->lc( "exif-$tag-$val" ), $arg );
	}

	/**
	 * Format a number, convert numbers from fractions into floating point
	 * numbers
	 *
	 * @private
	 *
	 * @param $num Mixed: the value to format
	 * @return mixed A floating point number or whatever we were fed
	 */
	function formatNum( $num ) {
		$m = array();
		if ( preg_match( '/^(\d+)\/(\d+)$/', $num, $m ) )
			return $m[2] != 0 ? $m[1] / $m[2] : $num;
		else
			return $num;
	}

	/**
	 * Format a rational number, reducing fractions
	 *
	 * @private
	 *
	 * @param $num Mixed: the value to format
	 * @return mixed A floating point number or whatever we were fed
	 */
	function formatFraction( $num ) {
		$m = array();
		if ( preg_match( '/^(\d+)\/(\d+)$/', $num, $m ) ) {
			$numerator = intval( $m[1] );
			$denominator = intval( $m[2] );
			$gcd = $this->gcd( $numerator, $denominator );
			if( $gcd != 0 ) {
				// 0 shouldn't happen! ;)
				return $numerator / $gcd . '/' . $denominator / $gcd;
			}
		}
		return $this->formatNum( $num );
	}

	/**
	 * Calculate the greatest common divisor of two integers.
	 *
	 * @param $a Integer: FIXME
	 * @param $b Integer: FIXME
	 * @return int
	 * @private
	 */
	function gcd( $a, $b ) {
		/*
			// http://en.wikipedia.org/wiki/Euclidean_algorithm
			// Recursive form would be:
			if( $b == 0 )
				return $a;
			else
				return gcd( $b, $a % $b );
		*/
		while( $b != 0 ) {
			$remainder = $a % $b;

			// tail recursion...
			$a = $b;
			$b = $remainder;
		}
		return $a;
	}
}

/**
 * MW 1.6 compatibility
 */
define( 'MW_EXIF_BYTE', Exif::BYTE );
define( 'MW_EXIF_ASCII', Exif::ASCII );
define( 'MW_EXIF_SHORT', Exif::SHORT );
define( 'MW_EXIF_LONG', Exif::LONG );
define( 'MW_EXIF_RATIONAL', Exif::RATIONAL );
define( 'MW_EXIF_UNDEFINED', Exif::UNDEFINED );
define( 'MW_EXIF_SLONG', Exif::SLONG );
define( 'MW_EXIF_SRATIONAL', Exif::SRATIONAL );