--- /dev/null
+<?php
+if (defined('MEDIAWIKI')) {
+/**
+ * @package MediaWiki
+ * @subpackage Metadata
+ *
+ * @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
+ *
+ * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
+ * @bug 1555, 1947
+ */
+
+/**
+ * @package MediaWiki
+ * @subpackage Metadata
+ */
+class Exif {
+ /**#@+
+ * @var array
+ */
+
+ /**
+ * 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
+ * seperated by commas.
+ *
+ * @access private
+ */
+ var $mExif;
+
+ /**
+ * A one dimentional array of all Exif tags
+ */
+ var $mFlatExif;
+
+ /**
+ * A one dimentional array of all Exif tags that we'd want to save in
+ * the database or present on a page.
+ */
+ var $mValidExif;
+
+ /**#@-*/
+
+ /**
+ * Constructor
+ */
+ function Exif() {
+ /**#@+
+ * Exif tag type definition
+ */
+ define('BYTE', 1); # An 8-bit unsigned integer.
+ define('ASCII', 2); # An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
+ define('SHORT', 3); # A 16-bit (2-byte) unsigned integer.
+ define('LONG', 4); # A 32-bit (4-byte) unsigned integer.
+ define('RATIONAL', 5); # Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
+ define('UNDEFINED', 7); # An 8-bit byte that can take any value depending on the field definition
+ define('SLONG', 9); # A 32-bit (4-byte) signed integer (2's complement notation),
+ define('SRATIONAL', 10); # Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.
+ /**#@-*/
+
+ /**
+ * 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->mExif = array(
+ # TIFF Rev. 6.0 Attribute Information (p22)
+ 'tiff' => array(
+ # Tags relating to image structure
+ 'structure' => array(
+ 'ImageWidth' => SHORT.','.LONG, # Image width
+ 'ImageLength' => SHORT.','.LONG, # Image height
+ 'BitsPerSample' => SHORT, # Number of bits per component
+ # "When a primary image is JPEG compressed, this designation is not"
+ # "necessary and is omitted." (p23)
+ 'Compression' => SHORT, # Compression scheme
+ 'PhotometricInterpretation' => SHORT, # Pixel composition #p23
+ 'Orientation' => SHORT, # Orientation of image #p24
+ 'SamplesPerPixel' => SHORT, # Number of components
+ 'PlanarConfiguration' => SHORT, # Image data arrangement #p24
+ 'YCbCrSubSampling' => SHORT, # Subsampling ratio of Y to C #p24
+ 'YCbCrPositioning' => SHORT, # Y and C positioning #p24-25
+ 'XResolution' => RATIONAL, # Image resolution in width direction
+ 'YResolution' => RATIONAL, # Image resolution in height direction
+ 'ResolutionUnit' => SHORT, # Unit of X and Y resolution #(p26)
+ ),
+
+ # Tags relating to recording offset
+ 'offset' => array(
+ 'StripOffsets' => SHORT.','.LONG, # Image data location
+ 'RowsPerStrip' => SHORT.','.LONG, # Number of rows per strip
+ 'StripByteCounts' => SHORT.','.LONG, # Bytes per compressed strip
+ 'JPEGInterchangeFormat' => SHORT.','.LONG, # Offset to JPEG SOI
+ 'JPEGInterchangeFormatLength' => SHORT.','.LONG, # Bytes of JPEG data
+ ),
+
+ # Tags relating to image data characteristics
+ 'characteristics' => array(
+ 'TransferFunction' => SHORT, # Transfer function
+ 'WhitePoint' => RATIONAL, # White point chromaticity
+ 'PrimaryChromaticities' => RATIONAL, # Chromaticities of primarities
+ 'YCbCrCoefficients' => RATIONAL, # Color space transformation matrix coefficients #p27
+ 'ReferenceBlackWhite' => RATIONAL # Pair of black and white reference values
+ ),
+
+ # Other tags
+ 'other' => array(
+ 'DateTime' => ASCII, # File change date and time
+ 'ImageDescription' => ASCII, # Image title
+ 'Make' => ASCII, # Image input equipment manufacturer
+ 'Model' => ASCII, # Image input equipment model
+ 'Software' => ASCII, # Software used
+ 'Artist' => ASCII, # Person who created the image
+ 'Copyright' => 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' => UNDEFINED, # Exif version
+ 'FlashpixVersion' => UNDEFINED, # Supported Flashpix version #p32
+ ),
+
+ # Tags relating to Image Data Characteristics
+ 'characteristics' => array(
+ 'ColorSpace' => SHORT, # Color space information #p32
+ ),
+
+ # Tags relating to image configuration
+ 'configuration' => array(
+ 'ComponentsConfiguration' => UNDEFINED, # Meaning of each component #p33
+ 'CompressedBitsPerPixel' => RATIONAL, # Image compression mode
+ 'PixelYDimension' => SHORT.','.LONG, # Valid image width
+ 'PixelXDimension' => SHORT.','.LONG, # Valind image height
+ ),
+
+ # Tags relating to related user information
+ 'user' => array(
+ 'MakerNote' => UNDEFINED, # Manufacturer notes
+ 'UserComment' => UNDEFINED, # User comments #p34
+ ),
+
+ # Tags relating to related file information
+ 'related' => array(
+ 'RelatedSoundFile' => ASCII, # Related audio file
+ ),
+
+ # Tags relating to date and time
+ 'dateandtime' => array(
+ 'DateTimeOriginal' => ASCII, # Date and time of original data generation #p36
+ 'DateTimeDigitized' => ASCII, # Date and time of original data generation
+ 'SubSecTime' => ASCII, # DateTime subseconds
+ 'SubSecTimeOriginal' => ASCII, # DateTimeOriginal subseconds
+ 'SubSecTimeDigitized' => ASCII, # DateTimeDigitized subseconds
+ ),
+
+ # Tags relating to picture-taking conditions (p31)
+ 'conditions' => array(
+ 'ExposureTime' => RATIONAL, # Exposure time
+ 'FNumber' => RATIONAL, # F Number
+ 'ExposureProgram' => SHORT, # Exposure Program #p38
+ 'SpectralSensitivity' => ASCII, # Spectral sensitivity
+ 'ISOSpeedRatings' => SHORT, # ISO speed rating
+ 'OECF' => UNDEFINED, # Optoelectronic conversion factor
+ 'ShutterSpeedValue' => SRATIONAL, # Shutter speed
+ 'ApertureValue' => RATIONAL, # Aperture
+ 'BrightnessValue' => SRATIONAL, # Brightness
+ 'ExposureBiasValue' => SRATIONAL, # Exposure bias
+ 'MaxApertureValue' => RATIONAL, # Maximum land aperture
+ 'SubjectDistance' => RATIONAL, # Subject distance
+ 'MeteringMode' => SHORT, # Metering mode #p40
+ 'LightSource' => SHORT, # Light source #p40-41
+ 'Flash' => SHORT, # Flash #p41-42
+ 'FocalLength' => RATIONAL, # Lens focal length
+ 'SubjectArea' => SHORT, # Subject area
+ 'FlashEnergy' => RATIONAL, # Flash energy
+ 'SpatialFrequencyResponse' => UNDEFINED, # Spatial frequency response
+ 'FocalPlaneXResolution' => RATIONAL, # Focal plane X resolution
+ 'FocalPlaneYResolution' => RATIONAL, # Focal plane Y resolution
+ 'FocalPlaneResolutionUnit' => SHORT, # Focal plane resolution unit
+ 'SubjectLocation' => SHORT, # Subject location
+ 'ExposureIndex' => RATIONAL, # Exposure index
+ 'SensingMethod' => SHORT, # Sensing method #p46
+ 'FileSource' => UNDEFINED, # File source #p47
+ 'SceneType' => UNDEFINED, # Scene type #p47
+ 'CFAPattern' => UNDEFINED, # CFA pattern
+ 'CustomRendered' => SHORT, # Custom image processing #p48
+ 'ExposureMode' => SHORT, # Exposure mode #p48
+ 'WhiteBalance' => SHORT, # White Balance #p49
+ 'DigitalZoomRatio' => RATIONAL, # Digital zoom ration
+ 'FocalLengthIn35mmFilm' => SHORT, # Focal length in 35 mm film
+ 'SceneCaptureType' => SHORT, # Scene capture type #p49
+ 'GainControl' => RATIONAL, # Scene control #p49-50
+ 'Contrast' => SHORT, # Contrast #p50
+ 'Saturation' => SHORT, # Saturation #p50
+ 'Sharpness' => SHORT, # Sharpness #p50
+ 'DeviceSettingDescription' => UNDEFINED, # Desice settings description
+ 'SubjectDistanceRange' => SHORT, # Subject distance range #p51
+ ),
+
+ 'other' => array(
+ 'ImageUniqueID' => ASCII, # Unique image ID
+ ),
+ ),
+
+ # GPS Attribute Information (p52)
+ 'gps' => array(
+ 'GPSVersionID' => BYTE, # GPS tag version
+ 'GPSLatitudeRef' => ASCII, # North or South Latitude #p52-53
+ 'GPSLatitude' => RATIONAL, # Latitude
+ 'GPSLongitudeRef' => ASCII, # East or West Longitude #p53
+ 'GPSLongitude' => RATIONAL, # Longitude
+ 'GPSAltitudeRef' => BYTE, # Altitude reference
+ 'GPSAltitude' => RATIONAL, # Altitude
+ 'GPSTimeStamp' => RATIONAL, # GPS time (atomic clock)
+ 'GPSSatellites' => ASCII, # Satellites used for measurement
+ 'GPSStatus' => ASCII, # Receiver status #p54
+ 'GPSMeasureMode' => ASCII, # Measurement mode #p54-55
+ 'GPSDOP' => RATIONAL, # Measurement precision
+ 'GPSSpeedRef' => ASCII, # Speed unit #p55
+ 'GPSSpeed' => RATIONAL, # Speed of GPS receiver
+ 'GPSTrackRef' => ASCII, # Reference for direction of movement #p55
+ 'GPSTrack' => RATIONAL, # Direction of movement
+ 'GPSImgDirectionRef' => ASCII, # Reference for direction of image #p56
+ 'GPSImgDirection' => RATIONAL, # Direction of image
+ 'GPSMapDatum' => ASCII, # Geodetic survey data used
+ 'GPSDestLatitudeRef' => ASCII, # Reference for latitude of destination #p56
+ 'GPSDestLatitude' => RATIONAL, # Latitude destination
+ 'GPSDestLongitudeRef' => ASCII, # Reference for longitude of destination #p57
+ 'GPSDestLongitude' => RATIONAL, # Longitude of destination
+ 'GPSDestBearingRef' => ASCII, # Reference for bearing of destination #p57
+ 'GPSDestBearing' => RATIONAL, # Bearing of destination
+ 'GPSDestDistanceRef' => ASCII, # Reference for distance to destination #p57-58
+ 'GPSDestDistance' => RATIONAL, # Distance to destination
+ 'GPSProcessingMethod' => UNDEFINED, # Name of GPS processing method
+ 'GPSAreaInformation' => UNDEFINED, # Name of GPS area
+ 'GPSDateStamp' => ASCII, # GPS date
+ 'GPSDifferential' => SHORT, # GPS differential correction
+ ),
+ );
+
+ $this->makeFlatExifTags();
+ $this->makeValidExifTags();
+ }
+
+ /**
+ * Get the raw list of exiftags
+ *
+ * @access private
+ * @return array
+ */
+ function getExif() {
+ return $this->mExif;
+ }
+
+ /**
+ * Generate a flat list of the exif tags
+ */
+ function makeFlatExifTags() {
+ $exif = $this->getExif();
+ array_walk($exif, array(&$this, 'callback')); // note the reference
+ }
+
+ /**
+ * A callback function used by makeFlatExifTags()
+ */
+ function callback($val, $key) {
+ if (gettype($val) === 'array')
+ array_walk($val, array(&$this, 'callback'));
+ else
+ $this->mFlatExif[$key] = $val;
+ }
+
+ /**
+ * Produce a list of all Exif tags appropriate for user output
+ *
+ * Produce a list of all tags that we want to show in output, in order not to
+ * output binary gibberish such as raw thumbnails we strip all tags
+ * with the datatype of UNDEFINED.
+ *
+ * @todo We might actually want to display some of the UNDEFINED
+ * stuff, but we strip it for now.
+ */
+ function makeValidExifTags() {
+ foreach($this->mFlatExif as $key => $val) {
+ if (strpos( $val, (string)UNDEFINED ) !== false)
+ continue;
+ $this->mValidExif[] = $key;
+ }
+ }
+
+ /**
+ * 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
+ */
+ function version() {
+ return 1; // We don't need no bloddy constants!
+ }
+}
+} // MEDIAWIKI