/add-ons/pjmt/EXIF.php

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<?



/******************************************************************************

*

* Filename:     EXIF.php

*

* Description:  Provides functions for reading and writing EXIF Information

*               to/from an APP1 segment of a JPEG file

*               Unfortunately, because EXIF data may be distributed anywhere

*               throughout an image file, rather than just being in one block,

*               it is impossible to pass just a string containing only the EXIF

*               information. Hence it is neccessary to be able to seek to

*               any point in the file. This causes the HTTP and FTP wrappers

*               not to work - i.e. the EXIF functions will only work with local

*               files.

*               To work on an internet file, copy it locally to start with:

*

*               $newfilename = tempnam ( $dir, "tmpexif" );

*               copy ( "http://whatever.com", $newfilename );

*

*

* Author:       Evan Hunter

*

* Date:         30/7/2004

*

* Project:      PHP JPEG Metadata Toolkit

*

* Revision:     1.11

*

* Changes:      1.00 -> 1.10 : added function get_EXIF_TIFF to allow extracting EXIF from a TIFF file

*               1.10 -> 1.11 : added functionality to allow decoding of XMP and Photoshop IRB information

*                              embedded within the EXIF data

*                              added checks for http and ftp wrappers, as these are not supported

*                              changed interpret_IFD to allow thumbnail links to work when

*                              toolkit is portable across directories

*

*

* URL:          http://electronics.ozhiker.com

*

* Copyright:    Copyright Evan Hunter 2004

*

* License:      This file is part of the PHP JPEG Metadata Toolkit.

*

*               The PHP JPEG Metadata Toolkit 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.

*

*               The PHP JPEG Metadata Toolkit 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 the PHP JPEG Metadata Toolkit; if not,

*               write to the Free Software Foundation, Inc., 59 Temple

*               Place, Suite 330, Boston, MA  02111-1307  USA

*

*               If you require a different license for commercial or other

*               purposes, please contact the author: evan@ozhiker.com

*

******************************************************************************/





// TODO : Thoroughly test the functions for writing EXIF segments

// TODO : Figure out a way to allow EXIF to function normally with HTTP and FTP wrappers

// TODO : Implement EXIF decoding of Device Setting Description field

// TODO : Implement EXIF decoding of SpatialFrequencyResponse field

// TODO : Implement EXIF decoding of OECF field

// TODO : Implement EXIF decoding of SubjectArea field

// TODO : Add a put_EXIF_TIFF function



/******************************************************************************

*

* Initialisation

*

******************************************************************************/





if ( !isset( $GLOBALS['HIDE_UNKNOWN_TAGS'] ) )     $GLOBALS['HIDE_UNKNOWN_TAGS']= FALSE;

if ( !isset( $GLOBALS['SHOW_BINARY_DATA_HEX'] ) )  $GLOBALS['SHOW_BINARY_DATA_HEX'] = FALSE;

if ( !isset( $GLOBALS['SHOW_BINARY_DATA_TEXT'] ) ) $GLOBALS['SHOW_BINARY_DATA_TEXT'] = FALSE;





include_once 'EXIF_Tags.php';

include_once 'EXIF_Makernote.php';

include_once 'PIM.php';

include_once 'Unicode.php';

include_once 'JPEG.php';

include_once 'IPTC.php';

include_once 'Photoshop_IRB.php';       // Change: as of version 1.11  - Required for TIFF with embedded IRB

include_once 'XMP.php';                 // Change: as of version 1.11  - Required for TIFF with embedded XMP

include_once 'pjmt_utils.php';          // Change: as of version 1.11  - Required for directory portability

















/******************************************************************************

*

* Function:     get_EXIF_JPEG

*

* Description:  Retrieves information from a Exchangeable Image File Format (EXIF)

*               APP1 segment and returns it in an array.

*

* Parameters:   filename - the filename of the JPEG image to process

*

* Returns:      OutputArray - Array of EXIF records

*               FALSE - If an error occured in decoding

*

******************************************************************************/



function get_EXIF_JPEG( $filename )

{

        // Change: Added as of version 1.11

        // Check if a wrapper is being used - these are not currently supported (see notes at top of file)

        if ( ( stristr ( $filename, "http://" ) != FALSE ) || ( stristr ( $filename, "ftp://" ) != FALSE ) )

        {

                // A HTTP or FTP wrapper is being used - show a warning and abort

                echo "HTTP and FTP wrappers are currently not supported with EXIF - See EXIF functionality documentation - a local file must be specified<br>";

                echo "To work on an internet file, copy it locally to start with:<br><br>\n";

                echo "\$newfilename = tempnam ( \$dir, \"tmpexif\" );<br>\n";

                echo "copy ( \"http://whatever.com\", \$newfilename );<br><br>\n";

                return FALSE;

        }



        // get the JPEG headers

        $jpeg_header_data = get_jpeg_header_data( $filename );





        // Flag that an EXIF segment has not been found yet

        $EXIF_Location = -1;



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // If we find an APP1 header,

                if ( strcmp ( $jpeg_header_data[$i]['SegName'], "APP1" ) == 0 )

                {

                        // And if it has the EXIF label,

                        if ( ( strncmp ( $jpeg_header_data[$i]['SegData'], "Exif\x00\x00", 6) == 0 ) ||

                             ( strncmp ( $jpeg_header_data[$i]['SegData'], "Exif\x00\xFF", 6) == 0 ) )          // For some reason, some files have a faulty EXIF name which has a 0xFF in it

                        {

                                // Save the location of the EXIF segment

                                $EXIF_Location = $i;

                        }

                }



        }



        // Check if an EXIF segment was found

        if ( $EXIF_Location == -1 )

        {

                // Couldn't find any EXIF block to decode

                return FALSE;

        }



        $filehnd = @fopen($filename, 'rb');



        // Check if the file opened successfully

        if ( ! $filehnd  )

        {

                // Could't open the file - exit

                echo "<p>Could not open file $filename</p>\n";

                return FALSE;

        }



        fseek( $filehnd, $jpeg_header_data[$EXIF_Location]['SegDataStart'] + 6  );



        // Decode the Exif segment into an array and return it

        $exif_data = process_TIFF_Header( $filehnd, "TIFF" );







        // Close File

        fclose($filehnd);

        return $exif_data;

}



/******************************************************************************

* End of Function:     get_EXIF_JPEG

******************************************************************************/







/******************************************************************************

*

* Function:     put_EXIF_JPEG

*

* Description:  Stores information into a Exchangeable Image File Format (EXIF)

*               APP1 segment from an EXIF array.

*

*               WARNING: Because the EXIF standard allows pointers to data

*               outside the APP1 segment, if there are any such pointers in

*               a makernote, this function will DAMAGE them since it will not

*               be aware that there is an external pointer. This will often

*               happen with Makernotes that include an embedded thumbnail.

*               This damage could be prevented where makernotes can be decoded,

*               but currently this is not implemented.

*

*

* Parameters:   exif_data - The array of EXIF data to insert into the JPEG header

*               jpeg_header_data - The JPEG header into which the EXIF data

*                                  should be stored, as from get_jpeg_header_data

*

* Returns:      jpeg_header_data - JPEG header array with the EXIF segment inserted

*               FALSE - If an error occured

*

******************************************************************************/



function put_EXIF_JPEG( $exif_data, $jpeg_header_data )

{

        // pack the EXIF data into its proper format for a JPEG file

        $packed_data = get_TIFF_Packed_Data( $exif_data );

        if ( $packed_data === FALSE )

        {

                return $jpeg_header_data;

        }



        $packed_data = "Exif\x00\x00$packed_data";



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // If we find an APP1 header,

                if ( strcmp ( $jpeg_header_data[$i]['SegName'], "APP1" ) == 0 )

                {

                        // And if it has the EXIF label,

                        if ( ( strncmp ( $jpeg_header_data[$i]['SegData'], "Exif\x00\x00", 6) == 0 ) ||

                             ( strncmp ( $jpeg_header_data[$i]['SegData'], "Exif\x00\xFF", 6) == 0 ) )          // For some reason, some files have a faulty EXIF name which has a 0xFF in it

                        {

                                // Found a preexisting EXIF block - Replace it with the new one and return.

                                $jpeg_header_data[$i]['SegData'] = $packed_data;

                                return $jpeg_header_data;

                        }

                }

        }



        // No preexisting segment segment found, insert a new one at the start of the header data.



        // Determine highest position of an APP segment at or below APP3, so we can put the

        // new APP3 at this position





        $highest_APP = -1;



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // Check if we have found an APP segment at or below APP3,

                if ( ( $jpeg_header_data[$i]['SegType'] >= 0xE0 ) && ( $jpeg_header_data[$i]['SegType'] <= 0xE3 ) )

                {

                        // Found an APP segment at or below APP12

                        $highest_APP = $i;

                }

        }



        // No preexisting EXIF block found, insert a new one at the start of the header data.

        array_splice($jpeg_header_data, $highest_APP + 1 , 0, array( array(   "SegType" => 0xE1,

                                                                              "SegName" => "APP1",

                                                                              "SegDesc" => $GLOBALS[ "JPEG_Segment_Descriptions" ][ 0xE1 ],

                                                                              "SegData" => $packed_data ) ) );

        return $jpeg_header_data;



}



/******************************************************************************

* End of Function:     put_EXIF_JPEG

******************************************************************************/









/******************************************************************************

*

* Function:     get_Meta_JPEG

*

* Description:  Retrieves information from a Meta APP3 segment and returns it

*               in an array. Uses information supplied by the

*               get_jpeg_header_data function.

*               The Meta segment has the same format as an EXIF segment, but

*               uses different tags

*

* Parameters:   filename - the filename of the JPEG image to process

*

* Returns:      OutputArray - Array of Meta records

*               FALSE - If an error occured in decoding

*

******************************************************************************/



function get_Meta_JPEG( $filename )

{

        // Change: Added as of version 1.11

        // Check if a wrapper is being used - these are not currently supported (see notes at top of file)

        if ( ( stristr ( $filename, "http://" ) != FALSE ) || ( stristr ( $filename, "ftp://" ) != FALSE ) )

        {

                // A HTTP or FTP wrapper is being used - show a warning and abort

                echo "HTTP and FTP wrappers are currently not supported with Meta - See EXIF/Meta functionality documentation - a local file must be specified<br>";

                echo "To work on an internet file, copy it locally to start with:<br><br>\n";

                echo "\$newfilename = tempnam ( \$dir, \"tmpmeta\" );<br>\n";

                echo "copy ( \"http://whatever.com\", \$newfilename );<br><br>\n";

                return FALSE;

        }



        // get the JPEG headers

        $jpeg_header_data = get_jpeg_header_data( $filename );





        // Flag that an Meta segment has not been found yet

        $Meta_Location = -1;



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // If we find an APP3 header,

                if  ( strcmp ( $jpeg_header_data[$i]['SegName'], "APP3" ) == 0 )

                {

                        // And if it has the Meta label,

                        if ( ( strncmp ( $jpeg_header_data[$i]['SegData'], "Meta\x00\x00", 6) == 0 ) ||

                             ( strncmp ( $jpeg_header_data[$i]['SegData'], "META\x00\x00", 6) == 0 ) )

                        {

                                // Save the location of the Meta segment

                                $Meta_Location = $i;

                        }

                }

        }



        // Check if an EXIF segment was found

        if ( $Meta_Location == -1 )

        {

                // Couldn't find any Meta block to decode

                return FALSE;

        }





        $filehnd = @fopen($filename, 'rb');



        // Check if the file opened successfully

        if ( ! $filehnd  )

        {

                // Could't open the file - exit

                echo "<p>Could not open file $filename</p>\n";

                return FALSE;

        }



        fseek( $filehnd, $jpeg_header_data[$Meta_Location]['SegDataStart'] + 6 );



        // Decode the Meta segment into an array and return it

        $meta = process_TIFF_Header( $filehnd, "Meta" );



         // Close File

        fclose($filehnd);



        return $meta;

}



/******************************************************************************

* End of Function:     get_Meta

******************************************************************************/















/******************************************************************************

*

* Function:     put_Meta_JPEG

*

* Description:  Stores information into a Meta APP3 segment from a Meta array.

*

*

*               WARNING: Because the Meta (EXIF) standard allows pointers to data

*               outside the APP1 segment, if there are any such pointers in

*               a makernote, this function will DAMAGE them since it will not

*               be aware that there is an external pointer. This will often

*               happen with Makernotes that include an embedded thumbnail.

*               This damage could be prevented where makernotes can be decoded,

*               but currently this is not implemented.

*

*

* Parameters:   meta_data - The array of Meta data to insert into the JPEG header

*               jpeg_header_data - The JPEG header into which the Meta data

*                                  should be stored, as from get_jpeg_header_data

*

* Returns:      jpeg_header_data - JPEG header array with the Meta segment inserted

*               FALSE - If an error occured

*

******************************************************************************/



function put_Meta_JPEG( $meta_data, $jpeg_header_data )

{

        // pack the Meta data into its proper format for a JPEG file

        $packed_data = get_TIFF_Packed_Data( $meta_data );

        if ( $packed_data === FALSE )

        {

                return $jpeg_header_data;

        }



        $packed_data = "Meta\x00\x00$packed_data";



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // If we find an APP1 header,

                if ( strcmp ( $jpeg_header_data[$i]['SegName'], "APP3" ) == 0 )

                {

                        // And if it has the Meta label,

                        if ( ( strncmp ( $jpeg_header_data[$i]['SegData'], "Meta\x00\x00", 6) == 0 ) ||

                             ( strncmp ( $jpeg_header_data[$i]['SegData'], "META\x00\x00", 6) == 0 ) )

                        {

                                // Found a preexisting Meta block - Replace it with the new one and return.

                                $jpeg_header_data[$i]['SegData'] = $packed_data;

                                return $jpeg_header_data;

                        }

                }

        }

        // No preexisting segment segment found, insert a new one at the start of the header data.



        // Determine highest position of an APP segment at or below APP3, so we can put the

        // new APP3 at this position





        $highest_APP = -1;



        //Cycle through the header segments

        for( $i = 0; $i < count( $jpeg_header_data ); $i++ )

        {

                // Check if we have found an APP segment at or below APP3,

                if ( ( $jpeg_header_data[$i]['SegType'] >= 0xE0 ) && ( $jpeg_header_data[$i]['SegType'] <= 0xE3 ) )

                {

                        // Found an APP segment at or below APP12

                        $highest_APP = $i;

                }

        }



        // No preexisting Meta block found, insert a new one at the start of the header data.

        array_splice($jpeg_header_data, $highest_APP + 1 , 0, array( array(     "SegType" => 0xE3,

                                                                                "SegName" => "APP3",

                                                                                "SegDesc" => $GLOBALS[ "JPEG_Segment_Descriptions" ][ 0xE1 ],

                                                                                "SegData" => $packed_data ) ) );

        return $jpeg_header_data;



}



/******************************************************************************

* End of Function:     put_Meta_JPEG

******************************************************************************/







/******************************************************************************

*

* Function:     get_EXIF_TIFF

*

* Description:  Retrieves information from a Exchangeable Image File Format (EXIF)

*               within a TIFF file and returns it in an array.

*

* Parameters:   filename - the filename of the TIFF image to process

*

* Returns:      OutputArray - Array of EXIF records

*               FALSE - If an error occured in decoding

*

******************************************************************************/



function get_EXIF_TIFF( $filename )

{

        // Change: Added as of version 1.11

        // Check if a wrapper is being used - these are not currently supported (see notes at top of file)

        if ( ( stristr ( $filename, "http://" ) != FALSE ) || ( stristr ( $filename, "ftp://" ) != FALSE ) )

        {

                // A HTTP or FTP wrapper is being used - show a warning and abort

                echo "HTTP and FTP wrappers are currently not supported with TIFF - See EXIF/TIFF functionality documentation - a local file must be specified<br>";

                echo "To work on an internet file, copy it locally to start with:<br><br>\n";

                echo "\$newfilename = tempnam ( \$dir, \"tmptiff\" );<br>\n";

                echo "copy ( \"http://whatever.com\", \$newfilename );<br><br>\n";

                return FALSE;

        }





        $filehnd = @fopen($filename, 'rb');



        // Check if the file opened successfully

        if ( ! $filehnd  )

        {

                // Could't open the file - exit

                echo "<p>Could not open file $filename</p>\n";

                return FALSE;

        }



        // Decode the Exif segment into an array and return it

        $exif_data = process_TIFF_Header( $filehnd, "TIFF" );



        // Close File

        fclose($filehnd);

        return $exif_data;

}



/******************************************************************************

* End of Function:     get_EXIF_TIFF

******************************************************************************/









/******************************************************************************

*

* Function:     Interpret_EXIF_to_HTML

*

* Description:  Generates html detailing the contents an APP1 EXIF array

*               which was retrieved with a get_EXIF_.... function.

*               Can also be used for APP3 Meta arrays.

*

* Parameters:   Exif_array - the EXIF array,as read from get_EXIF_....

*               filename - the name of the Image file being processed ( used

*                          by scripts which displays EXIF thumbnails)

*

* Returns:      output_str - A string containing the HTML

*

******************************************************************************/



function Interpret_EXIF_to_HTML( $Exif_array, $filename )

{

        // Create the string to receive the html output

        $output_str = "";



        // Check if the array to process is valid

        if ( $Exif_array === FALSE )

        {

                // Exif Array is not valid - abort processing

                return $output_str;

        }



        // Ouput the heading according to what type of tags were used in processing

        if ( $Exif_array[ 'Tags Name' ] == "TIFF" )

        {

                $output_str .= "<h2 class=\"EXIF_Main_Heading\">Contains Exchangeable Image File Format (EXIF) Information</h2>\n";

        }

        else if ( $Exif_array[ 'Tags Name' ] == "Meta" )

        {

                $output_str .= "<h2 class=\"EXIF_Main_Heading\">Contains META Information (APP3)</h2>\n";

        }

        else

        {

                $output_str .= "<h2 class=\"EXIF_Main_Heading\">Contains " . $Exif_array[ 'Tags Name' ] . " Information</h2>\n";

        }





        // Check that there are actually items to process in the array

        if ( count( $Exif_array ) < 1 )

        {

                // No items to process in array - abort processing

                return $output_str;

        }



        // Output secondary heading

        $output_str .= "<h3 class=\"EXIF_Secondary_Heading\">Main Image Information</h2>\n";



        // Interpret the zeroth IFD to html

        $output_str .= interpret_IFD( $Exif_array[0], $filename, $Exif_array['Byte_Align'] );



        // Check if there is a first IFD to process

        if ( array_key_exists( 1, $Exif_array ) )

        {

                // There is a first IFD for a thumbnail

                // Add a heading for it to the output

                $output_str .= "<h3 class=\"EXIF_Secondary_Heading\">Thumbnail Information</h2>\n";



                // Interpret the IFD to html and add it to the output

                $output_str .= interpret_IFD( $Exif_array[1], $filename, $Exif_array['Byte_Align'] );

        }



        // Cycle through any other IFD's

        $i = 2;

        while ( array_key_exists( $i, $Exif_array ) )

        {

                // Add a heading for the IFD

                $output_str .= "<h3  class=\"EXIF_Secondary_Heading\">Image File Directory (IFD) $i Information</h2>\n";



                // Interpret the IFD to html and add it to the output

                $output_str .= interpret_IFD( $Exif_array[$i], $filename, $Exif_array['Byte_Align'] );

                $i++;

        }



        // Return the resulting HTML

        return $output_str;

}



/******************************************************************************

* End of Function:     Interpret_EXIF_to_HTML

******************************************************************************/

































/******************************************************************************

*

*         INTERNAL FUNCTIONS

*

******************************************************************************/























/******************************************************************************

*

* Internal Function:     get_TIFF_Packed_Data

*

* Description:  Packs TIFF IFD data from EXIF or Meta into a form ready for

*               either a JPEG EXIF/Meta segment or a TIFF file

*               This function attempts to protect the contents of an EXIF makernote,

*               by ensuring that it remains in the same position relative to the

*               TIFF header

*

* Parameters:   tiff_data - the EXIF array,as read from get_EXIF_JPEG or get_Meta_JPEG

*

* Returns:      packed_data - A string containing packed segment

*

******************************************************************************/



function get_TIFF_Packed_Data( $tiff_data )

{

        // Check that the segment is valid

        if ( $tiff_data === FALSE )

        {

                return FALSE;

        }



        // Get the byte alignment

        $Byte_Align = $tiff_data['Byte_Align'];



        // Add the Byte Alignment to the Packed data

        $packed_data = $Byte_Align;



        // Add the TIFF ID to the Packed Data

        $packed_data .= put_IFD_Data_Type( 42, 3, $Byte_Align );



        // Create a string for the makernote

        $makernote = "";



        // Check if the makernote exists

        if ( $tiff_data[ 'Makernote_Tag' ] !== FALSE )

        {

                // A makernote exists - We need to ensure that it stays in the same position as it was

                // Put the Makernote before any of the IFD's by padding zeros to the correct offset

                $makernote .= str_repeat("\x00",( $tiff_data[ 'Makernote_Tag' ][ 'Offset' ] - 8 ) );

                $makernote .= $tiff_data[ 'Makernote_Tag' ]['Data'];

        }



        // Calculage where the zeroth ifd will be

        $ifd_offset = strlen( $makernote ) + 8;



        // Add the Zeroth IFD pointer to the packed data

        $packed_data .= put_IFD_Data_Type( $ifd_offset, 4, $Byte_Align );



        // Add the makernote to the packed data (if there was one)

        $packed_data .= $makernote;



        //Add the IFD's to the packed data

        $packed_data .= get_IFD_Array_Packed_Data( $tiff_data, $ifd_offset, $Byte_Align );



        // Return the result

        return $packed_data;

}



/******************************************************************************

* End of Function:     get_TIFF_Packed_Data

******************************************************************************/









/******************************************************************************

*

* Internal Function:     get_IFD_Array_Packed_Data

*

* Description:  Packs a chain of IFD's from EXIF or Meta segments into a form

*               ready for either a JPEG EXIF/Meta segment or a TIFF file

*

* Parameters:   ifd_data - the IFD chain array, as read from get_EXIF_JPEG or get_Meta_JPEG

*               Zero_IFD_offset - The offset to the first IFD from the start of the TIFF header

*               Byte_Align - the Byte alignment to use - "MM" or "II"

*

* Returns:      packed_data - A string containing packed IFD's

*

******************************************************************************/



function get_IFD_Array_Packed_Data( $ifd_data, $Zero_IFD_offset, $Byte_Align )

{

        // Create a string to receive the packed output

        $packed_data = "";



        // Count the IFDs

        $ifd_count = 0;

        foreach( $ifd_data as $key => $IFD )

        {

                // Make sure we only count the IFD's, not other information keys

                if ( is_numeric( $key ) )

                {

                        $ifd_count++;

                }

        }





        // Cycle through each IFD,

        for ( $ifdno = 0; $ifdno < $ifd_count; $ifdno++ )

        {

                // Check if this IFD is the last one

                if ( $ifdno == $ifd_count - 1 )

                {

                        // This IFD is the last one, get it's packed data

                        $packed_data .= get_IFD_Packed_Data( $ifd_data[ $ifdno ], $Zero_IFD_offset +strlen($packed_data), $Byte_Align, FALSE );

                }

                else

                {

                        // This IFD is NOT the last one, get it's packed data

                        $packed_data .= get_IFD_Packed_Data( $ifd_data[ $ifdno ], $Zero_IFD_offset +strlen($packed_data), $Byte_Align, TRUE );

                }



        }



        // Return the packed output

        return $packed_data;

}



/******************************************************************************

* End of Function:     get_IFD_Array_Packed_Data

******************************************************************************/







/******************************************************************************

*

* Internal Function:     get_IFD_Packed_Data

*

* Description:  Packs an IFD from EXIF or Meta segments into a form

*               ready for either a JPEG EXIF/Meta segment or a TIFF file

*

* Parameters:   ifd_data - the IFD chain array, as read from get_EXIF_JPEG or get_Meta_JPEG

*               IFD_offset - The offset to the IFD from the start of the TIFF header

*               Byte_Align - the Byte alignment to use - "MM" or "II"

*               Another_IFD - boolean - false if this is the last IFD in the chain

*                                     - true if it is not the last

*

* Returns:      packed_data - A string containing packed IFD's

*

******************************************************************************/



function get_IFD_Packed_Data( $ifd_data, $IFD_offset, $Byte_Align, $Another_IFD )

{



        $ifd_body_str = "";

        $ifd_data_str = "";



        $Tag_Definitions_Name = $ifd_data[ 'Tags Name' ];





        // Count the Tags in this IFD

        $tag_count = 0;

        foreach( $ifd_data as $key => $tag )

        {

                // Make sure we only count the Tags, not other information keys

                if ( is_numeric( $key ) )

                {

                        $tag_count++;

                }

        }



        // Add the Tag count to the packed data

        $packed_data = put_IFD_Data_Type( $tag_count, 3, $Byte_Align );



        // Calculate the total length of the IFD (without the offset data)

        $IFD_len = 2 + $tag_count * 12 + 4;





        // Cycle through each tag

        foreach( $ifd_data as $key => $tag )

        {

                // Make sure this is a tag, not another information key

                if ( is_numeric( $key ) )

                {



                        // Add the tag number to the packed data

                        $ifd_body_str .= put_IFD_Data_Type( $tag[ 'Tag Number' ], 3, $Byte_Align );



                        // Add the Data type to the packed data

                        $ifd_body_str .= put_IFD_Data_Type( $tag['Data Type'], 3, $Byte_Align );



                        // Check if this is a Print Image Matching entry

                        if ( $tag['Type'] == "PIM" )

                        {

                                // This is a Print Image Matching entry,

                                // encode it

                                $data = Encode_PIM( $tag, $Byte_Align );

                        }

                                // Check if this is a IPTC/NAA Record within the EXIF IFD

                        else if ( ( ( $Tag_Definitions_Name == "EXIF" ) || ( $Tag_Definitions_Name == "TIFF" ) ) &&

                                  ( $tag[ 'Tag Number' ] == 33723 ) )

                        {

                                // This is a IPTC/NAA Record, encode it

                                $data = put_IPTC( $tag['Data'] );

                        }

                                // Change: Check for embedded XMP as of version 1.11

                                // Check if this is a XMP Record within the EXIF IFD

                        else if ( ( ( $Tag_Definitions_Name == "EXIF" ) || ( $Tag_Definitions_Name == "TIFF" ) ) &&

                                  ( $tag[ 'Tag Number' ] == 700 ) )

                        {

                                // This is a XMP Record, encode it

                                $data = write_XMP_array_to_text( $tag['Data'] );

                        }

                                // Change: Check for embedded IRB as of version 1.11

                                // Check if this is a Photoshop IRB Record within the EXIF IFD

                        else if ( ( ( $Tag_Definitions_Name == "EXIF" ) || ( $Tag_Definitions_Name == "TIFF" ) ) &&

                                  ( $tag[ 'Tag Number' ] == 34377 ) )

                        {

                                // This is a Photoshop IRB Record, encode it

                                $data = pack_Photoshop_IRB_Data( $tag['Data'] );

                        }

                                // Exif Thumbnail Offset

                        else if ( ( $tag[ 'Tag Number' ] == 513 ) && ( $Tag_Definitions_Name == "TIFF" ) )

                        {

                                        // The Exif Thumbnail Offset is a pointer but of type Long, not Unknown

                                        // Hence we need to put the data into the packed string separately

                                        // Calculate the thumbnail offset

                                        $data_offset = $IFD_offset + $IFD_len + strlen($ifd_data_str);



                                        // Create the Offset for the IFD

                                        $data = put_IFD_Data_Type( $data_offset, 4, $Byte_Align );



                                        // Store the thumbnail

                                        $ifd_data_str .= $tag['Data'];

                        }

                                // Exif Thumbnail Length

                        else if ( ( $tag[ 'Tag Number' ] == 514 ) && ( $Tag_Definitions_Name == "TIFF" ) )

                        {

                                        // Encode the Thumbnail Length

                                        $data = put_IFD_Data_Type( strlen($ifd_data[513]['Data']), 4, $Byte_Align );

                        }

                                // Sub-IFD

                        else if ( $tag['Type'] == "SubIFD" )

                        {

                                        // This is a Sub-IFD

                                        // Calculate the offset to the start of the Sub-IFD

                                        $data_offset = $IFD_offset + $IFD_len + strlen($ifd_data_str);

                                        // Get the packed data for the IFD chain as the data for this tag

                                        $data = get_IFD_Array_Packed_Data( $tag['Data'], $data_offset, $Byte_Align );

                        }

                        else

                        {

                                // Not a special tag



                                // Create a string to receive the data

                                $data = "";



                                // Check if this is a type Unknown tag

                                if ( $tag['Data Type'] != 7 )

                                {

                                        // NOT type Unknown

                                        // Cycle through each data value and add it to the data string

                                        foreach( $tag[ 'Data' ] as $data_val )

                                        {

                                                $data .= put_IFD_Data_Type( $data_val, $tag['Data Type'], $Byte_Align );

                                        }

                                }

                                else

                                {

                                        // This is a type Unknown - just add the data as is to the data string

                                        $data .= $tag[ 'Data' ];

                                }

                        }



                        // Pad the data string out to at least 4 bytes

                        $data = str_pad ( $data, 4, "\x00" );





                        // Check if the data type is an ASCII String or type Unknown

                        if ( ( $tag['Data Type'] == 2 ) || ( $tag['Data Type'] == 7 ) )

                        {

                                // This is an ASCII String or type Unknown

                                // Add the Length of the string to the packed data as the Count

                                $ifd_body_str .= put_IFD_Data_Type( strlen($data), 4, $Byte_Align );

                        }

                        else

                        {

                                // Add the array count to the packed data as the Count

                                $ifd_body_str .= put_IFD_Data_Type( count($tag[ 'Data' ]), 4, $Byte_Align );

                        }





                        // Check if the data is over 4 bytes long

                        if ( strlen( $data ) > 4 )

                        {

                                // Data is longer than 4 bytes - it needs to be offset

                                // Check if this entry is the Maker Note

                                if ( ( $Tag_Definitions_Name == "EXIF" ) && ( $tag[ 'Tag Number' ] == 37500 ) )

                                {

                                        // This is the makernote - It will have already been stored

                                        // at its original offset to help preserve it

                                        // all we need to do is add the Offset to the IFD packed data

                                        $data_offset = $tag[ 'Offset' ];



                                        $ifd_body_str .= put_IFD_Data_Type( $data_offset, 4, $Byte_Align );

                                }

                                else

                                {

                                        // This is NOT the makernote

                                        // Calculate the data offset

                                        $data_offset = $IFD_offset + $IFD_len + strlen($ifd_data_str);



                                        // Add the offset to the IFD packed data

                                        $ifd_body_str .= put_IFD_Data_Type( $data_offset, 4, $Byte_Align );



                                        // Add the data to the offset packed data

                                        $ifd_data_str .= $data;

                                }

                        }

                        else

                        {

                                // Data is less than or equal to 4 bytes - Add it to the packed IFD data as is

                                $ifd_body_str .= $data;

                        }



                }

        }



        // Assemble the IFD body onto the packed data

        $packed_data .= $ifd_body_str;



        // Check if there is another IFD after this one

        if( $Another_IFD === TRUE )

        {

                // There is another IFD after this

                // Calculate the Next-IFD offset so that it goes immediately after this IFD

                $next_ifd_offset = $IFD_offset + $IFD_len + strlen($ifd_data_str);

        }

        else

        {

                // There is NO IFD after this - indicate with offset=0

                $next_ifd_offset = 0;

        }



        // Add the Next-IFD offset to the packed data

        $packed_data .= put_IFD_Data_Type( $next_ifd_offset, 4, $Byte_Align );



        // Add the offset data to the packed data

        $packed_data .= $ifd_data_str;



        // Return the resulting packed data

        return $packed_data;

}



/******************************************************************************

* End of Function:     get_IFD_Packed_Data

******************************************************************************/











/******************************************************************************

*

* Internal Function:     process_TIFF_Header

*

* Description:  Decodes the information stored in a TIFF header and it's

*               Image File Directories (IFD's). This information is returned

*               in an array

*

* Parameters:   filehnd - The handle of a open image file, positioned at the

*                          start of the TIFF header

*               Tag_Definitions_Name - The name of the Tag Definitions group

*                                      within the global array IFD_Tag_Definitions

*

*

* Returns:      OutputArray - Array of IFD records

*               FALSE - If an error occured in decoding

*

******************************************************************************/



function process_TIFF_Header( $filehnd, $Tag_Definitions_Name )

{





        // Save the file position where the TIFF header starts, as offsets are relative to this position

        $Tiff_start_pos = ftell( $filehnd );







        // Read the eight bytes of the TIFF header

        $DataStr = network_safe_fread( $filehnd, 8 );



        // Check that we did get all eight bytes

        if ( strlen( $DataStr ) != 8 )

        {

                return FALSE;   // Couldn't read the TIFF header properly

        }



        $pos = 0;

        // First two bytes indicate the byte alignment - should be 'II' or 'MM'

        // II = Intel (LSB first, MSB last - Little Endian)

        // MM = Motorola (MSB first, LSB last - Big Endian)

        $Byte_Align = substr( $DataStr, $pos, 2 );







        // Check the Byte Align Characters for validity

        if ( ( $Byte_Align != "II" ) && ( $Byte_Align != "MM" ) )

        {

                // Byte align field is invalid - we won't be able to decode file

                return FALSE;

        }



        // Skip over the Byte Align field which was just read

        $pos += 2;



        // Next two bytes are TIFF ID - should be value 42 with the appropriate byte alignment

        $TIFF_ID = substr( $DataStr, $pos, 2 );



        if ( get_IFD_Data_Type( $TIFF_ID, 3, $Byte_Align ) != 42 )

        {

                // TIFF header ID not found

                return FALSE;

        }



        // Skip over the TIFF ID field which was just read

        $pos += 2;





        // Next four bytes are the offset to the first IFD

        $offset_str = substr( $DataStr, $pos, 4 );

        $offset = get_IFD_Data_Type( $offset_str, 4, $Byte_Align );



        // Done reading TIFF Header





        // Move to first IFD



        if ( fseek( $filehnd, $Tiff_start_pos + $offset ) !== 0 )

        {

                // Error seeking to position of first IFD

                return FALSE;

        }







        // Flag that a makernote has not been found yet

        $GLOBALS[ "Maker_Note_Tag" ] = FALSE;



        // Read the IFD chain into an array

        $Output_Array = read_Multiple_IFDs( $filehnd, $Tiff_start_pos, $Byte_Align, $Tag_Definitions_Name );



        // Check if a makernote was found

        if ( $GLOBALS[ "Maker_Note_Tag" ] != FALSE )

        {

                // Makernote was found - Process it

                // The makernote needs to be processed after all other

                // tags as it may require some of the other tags in order

                // to be processed properly

                $GLOBALS[ "Maker_Note_Tag" ] = Read_Makernote_Tag( $GLOBALS[ "Maker_Note_Tag" ], $Output_Array, $filehnd );



        }



        $Output_Array[ 'Makernote_Tag' ] = $GLOBALS[ "Maker_Note_Tag" ];



        // Save the Name of the Tags used in the output array

        $Output_Array[ 'Tags Name' ] = $Tag_Definitions_Name;







        // Save the Byte alignment

        $Output_Array['Byte_Align'] = $Byte_Align;





        // Return the output array

        return $Output_Array ;

}



/******************************************************************************

* End of Function:     process_TIFF_Header

******************************************************************************/













/******************************************************************************

*

* Internal Function:     read_Multiple_IFDs

*

* Description:  Reads and interprets a chain of standard Image File Directories (IFD's),

*               and returns the entries in an array. This chain is made up from IFD's

*               which have a pointer to the next IFD. IFD's are read until the next

*               pointer indicates there are no more

*

* Parameters:   filehnd - a handle for the image file being read, positioned at the

*                         start of the IFD chain

*               Tiff_offset - The offset of the TIFF header from the start of the file

*               Byte_Align - either "MM" or "II" indicating Motorola or Intel Byte alignment

*               Tag_Definitions_Name - The name of the Tag Definitions group within the global array IFD_Tag_Definitions

*               local_offsets - True indicates that offset data should be interpreted as being relative to the start of the currrent entry

*                               False (normal) indicates offests are relative to start of Tiff header as per IFD standard

*               read_next_ptr - True (normal) indicates that a pointer to the next IFD should be read at the end of the IFD

*                               False indicates that no pointer follows the IFD

*

*

* Returns:      OutputArray - Array of IFD entries

*

******************************************************************************/



function read_Multiple_IFDs( $filehnd, $Tiff_offset, $Byte_Align, $Tag_Definitions_Name, $local_offsets = FALSE, $read_next_ptr = TRUE )

{

        // Start at the offset of the first IFD

        $Next_Offset = 0;



        do

        {

                // Read an IFD

                list($IFD_Array , $Next_Offset) = read_IFD_universal( $filehnd, $Tiff_offset, $Byte_Align, $Tag_Definitions_Name, $local_offsets, $read_next_ptr );



                // Move to the position of the next IFD

                if ( fseek( $filehnd, $Tiff_offset + $Next_Offset ) !== 0 )

                {

                        // Error seeking to position of next IFD

                        echo "<p>Error: Corrupted EXIF</p>\n";

                        return FALSE;

                }



                $Output_Array[] = $IFD_Array;





        } while ( $Next_Offset != 0 );      // Until the Next IFD Offset is zero





        // return resulting array



        return $Output_Array ;

}



/******************************************************************************

* End of Function:     read_Multiple_IFDs

******************************************************************************/















/******************************************************************************

*

* Internal Function:     read_IFD_universal

*

* Description:  Reads and interprets a standard or Non-standard Image File

*               Directory (IFD), and returns the entries in an array

*

* Parameters:   filehnd - a handle for the image file being read, positioned at the start

*                         of the IFD

*               Tiff_offset - The offset of the TIFF header from the start of the file

*               Byte_Align - either "MM" or "II" indicating Motorola or Intel Byte alignment

*               Tag_Definitions_Name - The name of the Tag Definitions group within the global array IFD_Tag_Definitions

*               local_offsets - True indicates that offset data should be interpreted as being relative to the start of the currrent entry

*                               False (normal) indicates offests are relative to start of Tiff header as per IFD standard

*               read_next_ptr - True (normal) indicates that a pointer to the next IFD should be read at the end of the IFD

*                               False indicates that no pointer follows the IFD

*

* Returns:      OutputArray - Array of IFD entries

*               Next_Offset - Offset to next IFD (zero = no next IFD)

*

******************************************************************************/



function read_IFD_universal( $filehnd, $Tiff_offset, $Byte_Align, $Tag_Definitions_Name, $local_offsets = FALSE, $read_next_ptr = TRUE )

{

        if ( ( $filehnd == NULL ) || ( feof( $filehnd ) ) )

        {

                return array (FA…

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