Could not open file $filename\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 )
{
// 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 "Could not open file $filename
\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: 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 .= "Contains Exchangeable Image File Format (EXIF) Information
\n";
}
else if ( $Exif_array[ 'Tags Name' ] == "Meta" )
{
$output_str .= "Contains META Information (APP3)
\n";
}
else
{
$output_str .= "Contains " . $Exif_array[ 'Tags Name' ] . " Information
\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 .= "Main Image Information\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 .= "Thumbnail Information\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 .= "Image File Directory (IFD) $i Information\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, encoded it
$data = put_IPTC( $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 "
Error: Corrupted EXIF
\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 (FALSE , 0);
}
// Record the Name of the Tag Group used for this IFD in the output array
$OutputArray[ 'Tags Name' ] = $Tag_Definitions_Name;
// Record the offset of the TIFF header in the output array
$OutputArray[ 'Tiff Offset' ] = $Tiff_offset;
// First 2 bytes of IFD are number of entries in the IFD
$No_Entries_str = network_safe_fread( $filehnd, 2 );
$No_Entries = get_IFD_Data_Type( $No_Entries_str, 3, $Byte_Align );
// If the data is corrupt, the number of entries may be huge, which will cause errors
// This is often caused by a lack of a Next-IFD pointer
if ( $No_Entries> 10000 )
{
// Huge number of entries - abort
echo "Error: huge number of EXIF entries - EXIF is probably Corrupted
\n";
return array ( FALSE , 0);
}
// If the data is corrupt or just stupid, the number of entries may zero,
// Indicate this by returning false
if ( $No_Entries === 0 )
{
// No entries - abort
return array ( FALSE , 0);
}
// Save the file position where first IFD record starts as non-standard offsets
// need to know this to calculate an absolute offset
$IFD_first_rec_pos = ftell( $filehnd );
// Read in the IFD structure
$IFD_Data = network_safe_fread( $filehnd, 12 * $No_Entries );
// Check if the entire IFD was able to be read
if ( strlen( $IFD_Data ) != (12 * $No_Entries) )
{
// Couldn't read the IFD Data properly, Some Casio files have no Next IFD pointer, hence cause this error
echo "Error: EXIF Corrupted
\n";
return array(FALSE, 0);
}
// Last 4 bytes of a standard IFD are the offset to the next IFD
// Some NON-Standard IFD implementations do not have this, hence causing problems if it is read
// If the Next IFD pointer has been requested to be read,
if ( $read_next_ptr )
{
// Read the pointer to the next IFD
$Next_Offset_str = network_safe_fread( $filehnd, 4 );
$Next_Offset = get_IFD_Data_Type( $Next_Offset_str, 4, $Byte_Align );
}
else
{
// Otherwise set the pointer to zero ( no next IFD )
$Next_Offset = 0;
}
// Initialise current position to the start
$pos = 0;
// Loop for reading IFD entries
for ( $i = 0; $i < $No_Entries; $i++ )
{
// First 2 bytes of IFD entry are the tag number ( Unsigned Short )
$Tag_No_str = substr( $IFD_Data, $pos, 2 );
$Tag_No = get_IFD_Data_Type( $Tag_No_str, 3, $Byte_Align );
$pos += 2;
// Next 2 bytes of IFD entry are the data format ( Unsigned Short )
$Data_Type_str = substr( $IFD_Data, $pos, 2 );
$Data_Type = get_IFD_Data_Type( $Data_Type_str, 3, $Byte_Align );
$pos += 2;
// If Datatype is not between 1 and 12, then skip this entry, it is probably corrupted or custom
if (( $Data_Type > 12 ) || ( $Data_Type < 1 ) )
{
$pos += 8;
continue 1; // Stop trying to process the tag any further and skip to the next one
}
// Next 4 bytes of IFD entry are the data count ( Unsigned Long )
$Data_Count_str = substr( $IFD_Data, $pos, 4 );
$Data_Count = get_IFD_Data_Type( $Data_Count_str, 4, $Byte_Align );
$pos += 4;
if ( $Data_Count > 100000 )
{
echo "Error: huge EXIF data count - EXIF is probably Corrupted
\n";
// Some Casio files have no Next IFD pointer, hence cause errors
return array ( FALSE , 0);
}
// Total Data size is the Data Count multiplied by the size of the Data Type
$Total_Data_Size = $GLOBALS['IFD_Data_Sizes'][ $Data_Type ] * $Data_Count;
$Data_Start_pos = -1;
// If the total data size is larger than 4 bytes, then the data part is the offset to the real data
if ( $Total_Data_Size > 4 )
{
// Not enough room for data - offset provided instead
$Data_Offset_str = substr( $IFD_Data, $pos, 4 );
$Data_Start_pos = get_IFD_Data_Type( $Data_Offset_str, 4, $Byte_Align );
// In some NON-STANDARD makernotes, the offset is relative to the start of the current IFD entry
if ( $local_offsets )
{
// This is a NON-Standard IFD, seek relative to the start of the current tag
fseek( $filehnd, $IFD_first_rec_pos + $pos - 8 + $Data_Start_pos );
}
else
{
// This is a normal IFD, seek relative to the start of the TIFF header
fseek( $filehnd, $Tiff_offset + $Data_Start_pos );
}
// Read the data block from the offset position
$DataStr = network_safe_fread( $filehnd, $Total_Data_Size );
}
else
{
// The data block is less than 4 bytes, and is provided in the IFD entry, so read it
$DataStr = substr( $IFD_Data, $pos, $Total_Data_Size );
}
// Increment the position past the data
$pos += 4;
// Now create the entry for output array
$Data_Array = array( );
// Read the data items from the data block
if ( ( $Data_Type != 2 ) && ( $Data_Type != 7 ) )
{
// The data type is Numerical, Read the data items from the data block
for ( $j = 0; $j < $Data_Count; $j++ )
{
$Part_Data_Str = substr( $DataStr, $j * $GLOBALS['IFD_Data_Sizes'][ $Data_Type ], $GLOBALS['IFD_Data_Sizes'][ $Data_Type ] );
$Data_Array[] = get_IFD_Data_Type( $Part_Data_Str, $Data_Type, $Byte_Align );
}
}
elseif ( $Data_Type == 2 )
{
// The data type is String(s) (type 2)
// Strip the last terminating Null
$DataStr = substr( $DataStr, 0, strlen($DataStr)-1 );
// Split the data block into multiple strings whereever there is a Null
$Data_Array = explode( "\x00", $DataStr );
}
else
{
// The data type is Unknown (type 7)
// Do nothing to data
$Data_Array = $DataStr;
}
// If this is a Sub-IFD entry,
if ( ( array_key_exists( $Tag_No, $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name] ) ) &&
( "SubIFD" == $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Type'] ) )
{
// This is a Sub-IFD entry, go and process the data forming Sub-IFD and use its output array as the new data for this entry
fseek( $filehnd, $Tiff_offset + $Data_Array[0] );
$Data_Array = read_Multiple_IFDs( $filehnd, $Tiff_offset, $Byte_Align, $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Tags Name'] );
}
$desc = "";
$units = "";
// Check if this tag exists in the list of tag definitions,
if ( array_key_exists ( $Tag_No, $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name]) )
{
if ( array_key_exists ( 'Description', $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ] ) )
{
$desc = $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Description'];
}
if ( array_key_exists ( 'Units', $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ] ) )
{
$units = $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Units'];
}
// Tag exists in definitions, append details to output array
$OutputArray[ $Tag_No ] = array ( "Tag Number" => $Tag_No,
"Tag Name" => $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Name'],
"Tag Description" => $desc,
"Data Type" => $Data_Type,
"Type" => $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag_No ]['Type'],
"Units" => $units,
"Data" => $Data_Array );
}
else
{
// Tag doesnt exist in definitions, append unknown details to output array
$OutputArray[ $Tag_No ] = array ( "Tag Number" => $Tag_No,
"Tag Name" => "Unknown Tag #" . $Tag_No,
"Tag Description" => "",
"Data Type" => $Data_Type,
"Type" => "Unknown",
"Units" => "",
"Data" => $Data_Array );
}
// Some information of type "Unknown" (type 7) might require information about
// how it's position and byte alignment in order to be decoded
if ( $Data_Type == 7 )
{
$OutputArray[ $Tag_No ]['Offset'] = $Data_Start_pos;
$OutputArray[ $Tag_No ]['Byte Align'] = $Byte_Align;
}
////////////////////////////////////////////////////////////////////////
// Special Data handling
////////////////////////////////////////////////////////////////////////
// Check if this is a Print Image Matching entry
if ( $OutputArray[ $Tag_No ]['Type'] == "PIM" )
{
// This is a Print Image Matching entry, decode it.
$OutputArray[ $Tag_No ] = Decode_PIM( $OutputArray[ $Tag_No ], $Tag_Definitions_Name );
}
// Interpret the entry into a text string using a custom interpreter
$text_val = get_Tag_Text_Value( $OutputArray[ $Tag_No ], $Tag_Definitions_Name );
// Check if a text string was generated
if ( $text_val !== FALSE )
{
// A string was generated, append it to the output array entry
$OutputArray[ $Tag_No ]['Text Value'] = $text_val;
$OutputArray[ $Tag_No ]['Decoded'] = TRUE;
}
else
{
// A string was NOT generated, append a generic string to the output array entry
$OutputArray[ $Tag_No ]['Text Value'] = get_IFD_value_as_text( $OutputArray[ $Tag_No ] ) . " " . $units;
$OutputArray[ $Tag_No ]['Decoded'] = FALSE;
}
// Check if this entry is the Maker Note
if ( ( $Tag_Definitions_Name == "EXIF" ) && ( $Tag_No == 37500 ) )
{
// Save some extra information which will allow Makernote Decoding with the output array entry
$OutputArray[ $Tag_No ]['Offset'] = $Data_Start_pos;
$OutputArray[ $Tag_No ][ 'Tiff Offset' ] = $Tiff_offset;
$OutputArray[ $Tag_No ]['ByteAlign'] = $Byte_Align;
// Save a pointer to this entry for Maker note processing later
$GLOBALS[ "Maker_Note_Tag" ] = & $OutputArray[ $Tag_No ];
}
// Check if this is a IPTC/NAA Record within the EXIF IFD
if ( ( ( $Tag_Definitions_Name == "EXIF" ) || ( $Tag_Definitions_Name == "TIFF" ) ) &&
( $Tag_No == 33723 ) )
{
// This is a IPTC/NAA Record, interpret it and put result in the data for this entry
$OutputArray[ $Tag_No ]['Data'] = get_IPTC( $DataStr );
$OutputArray[ $Tag_No ]['Decoded'] = TRUE;
}
// Exif Thumbnail
// Check that both the thumbnail length and offset entries have been processed,
// and that this is one of them
if ( ( ( ( $Tag_No == 513 ) && ( array_key_exists( 514, $OutputArray ) ) ) ||
( ( $Tag_No == 514 ) && ( array_key_exists( 513, $OutputArray ) ) ) ) &&
( $Tag_Definitions_Name == "TIFF" ) )
{
// Seek to the start of the thumbnail using the offset entry
fseek( $filehnd, $Tiff_offset + $OutputArray[513]['Data'][0] );
// Read the thumbnail data, and replace the offset data with the thumbnail
$OutputArray[513]['Data'] = network_safe_fread( $filehnd, $OutputArray[514]['Data'][0] );
}
// Casio Thumbnail
// Check that both the thumbnail length and offset entries have been processed,
// and that this is one of them
if ( ( ( ( $Tag_No == 0x0004 ) && ( array_key_exists( 0x0003, $OutputArray ) ) ) ||
( ( $Tag_No == 0x0003 ) && ( array_key_exists( 0x0004, $OutputArray ) ) ) ) &&
( $Tag_Definitions_Name == "Casio Type 2" ) )
{
// Seek to the start of the thumbnail using the offset entry
fseek( $filehnd, $Tiff_offset + $OutputArray[0x0004]['Data'][0] );
// Read the thumbnail data, and replace the offset data with the thumbnail
$OutputArray[0x0004]['Data'] = network_safe_fread( $filehnd, $OutputArray[0x0003]['Data'][0] );
}
// Minolta Thumbnail
// Check that both the thumbnail length and offset entries have been processed,
// and that this is one of them
if ( ( ( ( $Tag_No == 0x0088 ) && ( array_key_exists( 0x0089, $OutputArray ) ) ) ||
( ( $Tag_No == 0x0089 ) && ( array_key_exists( 0x0088, $OutputArray ) ) ) ) &&
( $Tag_Definitions_Name == "Olympus" ) )
{
// Seek to the start of the thumbnail using the offset entry
fseek( $filehnd, $Tiff_offset + $OutputArray[0x0088]['Data'][0] );
// Read the thumbnail data, and replace the offset data with the thumbnail
$OutputArray[0x0088]['Data'] = network_safe_fread( $filehnd, $OutputArray[0x0089]['Data'][0] );
// Sometimes the minolta thumbnail data is empty (or the offset is corrupt, which results in the same thing)
// Check if the thumbnail data exists
if ( $OutputArray[0x0088]['Data'] != "" )
{
// Thumbnail exists
// Minolta Thumbnails are missing their first 0xFF for some reason,
// which is replaced with some weird character, so fix this
$OutputArray[0x0088]['Data']{0} = "\xFF";
}
else
{
// Thumbnail doesnt exist - make it obvious
$OutputArray[0x0088]['Data'] = FALSE;
}
}
}
// Return the array of IFD entries and the offset to the next IFD
return array ($OutputArray , $Next_Offset);
}
/******************************************************************************
* End of Function: read_IFD_universal
******************************************************************************/
/******************************************************************************
*
* Internal Function: get_Tag_Text_Value
*
* Description: Attempts to interpret an IFD entry into a text string using the
* information in the IFD_Tag_Definitions global array.
*
* Parameters: Tag - The IFD entry to process
* Tag_Definitions_Name - The name of the tag definitions to use from within the IFD_Tag_Definitions global array
*
* Returns: String - if the tag was successfully decoded into a text string
* FALSE - if the tag could not be decoded using the information
* in the IFD_Tag_Definitions global array
*
******************************************************************************/
function get_Tag_Text_Value( $Tag, $Tag_Definitions_Name )
{
// Check what format the entry is specified as
if ( $Tag['Type'] == "String" )
{
// Format is Text String
// If "Unknown" (type 7) data type,
if ( $Tag['Data Type'] == 7 )
{
// Return data as is.
return $Tag['Data'];
}
else
{
// Otherwise return the default string value of the datatype
return get_IFD_value_as_text( $Tag );
}
}
else if ( $Tag['Type'] == "Character Coded String" )
{
// Format is Character Coded String (First 8 characters indicate coding scheme)
// Convert Data to a string
if ( $Tag['Data Type'] == 7 )
{
// If it is type "Unknown" (type 7) use data as is
$data = $Tag['Data'];
}
else
{
// Otherwise use the default string value of the datatype
$data = get_IFD_value_as_text( $Tag );
}
// Some implementations allow completely data with no Coding Scheme Name,
// so we need to handle this to avoid errors
if ( trim( $data ) == "" )
{
return "";
}
// Extract the Coding Scheme Name from the first 8 characters
$char_code = substr( $data, 0, 8 );
// Extract the Data part from after the first 8 characters
$characters = substr( $data, 8 );
// Check coding scheme and interpret as neccessary
if ( $char_code === "ASCII\x00\x00\x00" )
{
// ASCII coding - return data as is.
return $characters;
}
elseif ( ( $char_code === "UNICODE\x00" ) ||
( $char_code === "Unicode\x00" ) ) // Note lowercase is non standard
{
// Unicode coding - interpret and return result.
return xml_UTF16_clean( $characters, TRUE );
}
else
{
// Unknown coding - return string indicating this
return "Unsupported character coding : \"$char_code\"\n\"" . trim($characters) . "\"";
}
break;
}
else if ( $Tag['Type'] == "Numeric" )
{
// Format is numeric - return default text value with any required units text appended
if ( array_key_exists ( 'Units', $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag["Tag Number"] ] ) )
{
$units = $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag["Tag Number"] ]['Units'];
}
else
{
$units = "";
}
return get_IFD_value_as_text( $Tag ) . " " . $units;
}
else if ( $Tag['Type'] == "Lookup" )
{
// Format is a Lookup Table
// Get a numeric value to use in lookup
if ( is_array( $Tag['Data'] ) )
{
// If data is an array, use first element
$first_val = $Tag['Data'][0];
}
else if ( is_string( $Tag['Data'] ) )
{
// If data is a string, use the first character
$first_val = ord($Tag['Data']{0});
}
else
{
// Otherwise use the data as is
$first_val = $Tag['Data'];
}
// Check if the data value exists in the lookup table for this IFD entry
if ( array_key_exists( $first_val, $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag["Tag Number"] ] ) )
{
// Data value exists in lookup table - return the matching string
return $GLOBALS[ "IFD_Tag_Definitions" ][$Tag_Definitions_Name][ $Tag["Tag Number"] ][ $first_val ];
}
else
{
// Data value doesnt exist in lookup table - return explanation string
return "Unknown Reserved value $first_val ";
}
}
else if ( $Tag['Type'] == "Special" )
{
// Format is special - interpret to text with special handlers
return get_Special_Tag_Text_Value( $Tag, $Tag_Definitions_Name );
}
else if ( $Tag['Type'] == "PIM" )
{
// Format is Print Image Matching info - interpret with custom handler
return get_PIM_Text_Value( $Tag, $Tag_Definitions_Name );
}
else if ( $Tag['Type'] == "SubIFD" )
{
// Format is a Sub-IFD - this has no text value
return "";
}
else
{
// Unknown Format - Couldn't interpret using the IFD_Tag_Definitions global array information
return FALSE;
}
}
/******************************************************************************
* End of Function: get_Tag_Text_Value
******************************************************************************/
/******************************************************************************
*
* Internal Function: get_Special_Tag_Text_Value
*
* Description: Interprets an IFD entry marked as "Special" in the IFD_Tag_Definitions
* global array into a text string using custom handlers
*
* Parameters: Tag - The IFD entry to process
* Tag_Definitions_Name - The name of the tag definitions to use from within the IFD_Tag_Definitions global array
*
* Returns: String - if the tag was successfully decoded into a text string
* FALSE - if the tag could not be decoded
*
******************************************************************************/
function get_Special_Tag_Text_Value( $Tag, $Tag_Definitions_Name )
{
// Check what type of IFD is being decoded
if ( $Tag_Definitions_Name == "TIFF" )
{
// This is a TIFF IFD (bottom level)
// Check what tag number the IFD entry has.
switch ( $Tag['Tag Number'] )
{
case 530: // YCbCr Sub Sampling Entry
// Data contains two numerical values
if ( ( $Tag['Data'][0] == 2 ) && ( $Tag['Data'][1] == 1 ) )
{
// Values are 2,1 - hence YCbCr 4:2:2
return "YCbCr 4:2:2 ratio of chrominance components to the luminance components";
}
elseif ( ( $Tag['Data'][0] == 2 ) && ( $Tag['Data'][1] == 2 ) )
{
// Values are 2,2 - hence YCbCr 4:2:0
return "YCbCr 4:2:0 ratio of chrominance components to the luminance components";
}
else
{
// Other values are unknown
return "Unknown Reserved value (" . $Tag['Data'][0] . ")";
}
break;
default:
return FALSE;
}
}
else if ( $Tag_Definitions_Name == "EXIF" )
{
// This is an EXIF IFD
// Check what tag number the IFD entry has.
switch ( $Tag['Tag Number'] )
{
case 37121: // Components configuration
// Data contains 4 numerical values indicating component type
$output_str = "";
// Cycle through each component
for ( $Num = 0; $Num < 4; $Num++ )
{
// Construct first part of text string
$output_str .= "Component " . ( $Num + 1 ) . ": ";
// Construct second part of text string via
// lookup using numerical value
$value = ord( $Tag['Data']{$Num} );
switch( $value )
{
case 0:
$output_str .= "Does not exist\n";
break;
case 1:
$output_str .= "Y (Luminance)\n";
break;
case 2:
$output_str .= "Cb (Chroma minus Blue)\n";
break;
case 3:
$output_str .= "Cr (Chroma minus Red)\n";
break;
case 4:
$output_str .= "Red\n";
break;
case 5:
$output_str .= "Green\n";
break;
case 6:
$output_str .= "Blue\n";
break;
default:
$output_str .= "Unknown value $value\n";
};
}
// Return the completed string
return $output_str;
break;
case 41730: // Colour Filter Array Pattern
// The first two characters are a SHORT for Horizontal repeat pixel unit -
$n_max = get_IFD_Data_Type( substr( $Tag['Data'], 0, 2 ), 3, $Tag['Byte Align'] );
// The next two characters are a SHORT for Vertical repeat pixel unit -
$m_max = get_IFD_Data_Type( substr( $Tag['Data'], 2, 2 ), 3, $Tag['Byte Align'] );
// At least one camera type appears to have byte reversed values for N_Max and M_Max
// Check if they need reversing
if ( $n_max > 256 )
{
$n_max = $n_max/256 + 256*($n_max%256);
}
if ( $m_max > 256 )
{
$m_max = $m_max/256 + 256*($m_max%256);
}
$output_str = "";
// Cycle through all the elements in the resulting 2 dimensional array,
for( $m = 1; $m <= $m_max; $m++ )
{
for( $n = 1; $n <= $n_max; $n++ )
{
// Append text from a lookup table according to
// the value read for this element
switch ( ord($Tag['Data']{($n_max*($m-1)+$n+3)}) )
{
case 0:
$output_str .= "RED ";
break;
case 1:
$output_str .= "GREEN ";
break;
case 2:
$output_str .= "BLUE ";
break;
case 3:
$output_str .= "CYAN ";
break;
case 4:
$output_str .= "MAGENTA ";
break;
case 5:
$output_str .= "YELLOW ";
break;
case 6:
$output_str .= "WHITE ";
break;
default:
$output_str .= "Unknown ";
break;
};
};
$output_str .= "\n";
};
// Return the resulting string
return $output_str;
break;
default:
return FALSE;
}
}
else
{
// Unknown IFD type, see if it is part of a makernote
return get_Makernote_Text_Value( $Tag, $Tag_Definitions_Name );
}
}
/******************************************************************************
* End of Function: get_Tag_Text_Value
******************************************************************************/
/******************************************************************************
*
* Function: interpret_IFD
*
* Description: Generates html detailing the contents a single IFD.
*
* Parameters: IFD_array - the array containing an IFD
* 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_IFD( $IFD_array, $filename )
{
// Create the output string with the table tag
$output_str = "\n";
// Create an extra output string to receive any supplementary html
// which cannot go inside the table
$extra_IFD_str = "";
// Check that the IFD array is valid
if ( ( $IFD_array === FALSE ) || ( $IFD_array === NULL ) )
{
// the IFD array is NOT valid - exit
return "";
}
// Check if this is an EXIF IFD and if there is a makernote present
if ( ( $IFD_array['Tags Name'] === "EXIF" ) &&
( ! array_key_exists( 37500, $IFD_array ) ) )
{
// This is an EXIF IFD but NO makernote is present - Add a message to the output
$extra_IFD_str .= "No Makernote Present
";
}
// Cycle through each tag in the IFD
foreach( $IFD_array as $Tag_ID => $Exif_Tag )
{
// Ignore the non numeric elements - they aren't tags
if ( ! is_numeric ( $Tag_ID ) )
{
// Skip Tags Name
}
// Check if the Tag has been decoded successfully
else if ( $Exif_Tag['Decoded'] == TRUE )
{
// This tag has been successfully decoded
// Table cells won't get drawn with nothing in them -
// Ensure that at least a non breaking space exists in them
if ( trim($Exif_Tag['Text Value']) == "" )
{
$Exif_Tag['Text Value'] = " ";
}
// Check if the tag is a sub-IFD
if ( $Exif_Tag['Type'] == "SubIFD" )
{
// This is a sub-IFD tag
// Add a sub-heading for the sub-IFD
$extra_IFD_str .= "" . $Exif_Tag['Tag Name'] . " contents
";
// Cycle through each sub-IFD in the chain
foreach ( $Exif_Tag['Data'] as $subIFD )
{
// Interpret this sub-IFD and add the html to the secondary output
$extra_IFD_str .= interpret_IFD( $subIFD, $filename );
}
}
// Check if the tag is a makernote
else if ( $Exif_Tag['Type'] == "Maker Note" )
{
// This is a Makernote Tag
// Add a sub-heading for the Makernote
$extra_IFD_str .= "Maker Note Contents
";
// Interpret the Makernote and add the html to the secondary output
$extra_IFD_str .= Interpret_Makernote_to_HTML( $Exif_Tag, $filename );
}
// Check if this is a IPTC/NAA Record within the EXIF IFD
else if ( $Exif_Tag['Type'] == "IPTC" )
{
// This is a IPTC/NAA Record, interpret it and output to the secondary html
$extra_IFD_str .= "Contains IPTC/NAA Embedded in EXIF
";
$extra_IFD_str .=Interpret_IPTC_to_HTML( $Exif_Tag['Data'] );
}
// Check if the tag is Numeric
else if ( $Exif_Tag['Type'] == "Numeric" )
{
// Numeric Tag - Output text value as is.
$output_str .= "| " . $Exif_Tag['Tag Name'] . " | " . $Exif_Tag['Text Value'] . " |
\n";
}
else
{
// Other tag - Output text as preformatted
$output_str .= "| " . $Exif_Tag['Tag Name'] . " | " . trim( $Exif_Tag['Text Value']) . " |
\n";
}
}
else
{
// Tag has NOT been decoded successfully
// Hence it is either an unknown tag, or one which
// requires processing at the time of html construction
// Table cells won't get drawn with nothing in them -
// Ensure that at least a non breaking space exists in them
if ( trim($Exif_Tag['Text Value']) == "" )
{
$Exif_Tag['Text Value'] = " ";
}
// Check if this tag is the first IFD Thumbnail
if ( ( $IFD_array['Tags Name'] == "TIFF" ) &&
( $Tag_ID == 513 ) )
{
// This is the first IFD thumbnail - Add html to the output
$output_str .= "| " . $Exif_Tag['Tag Name'] . " | ![](\"get_exif_thumb.php?filename=$filename\") |
\n";
}
// Check if this is the Makernote
else if ( $Exif_Tag['Type'] == "Maker Note" )
{
// This is the makernote, but has not been decoded
// Add a message to the secondary output
$extra_IFD_str .= "Makernote Coding Unknown
\n";
}
else
{
// This is an Unknown Tag
// Check if the user wants to hide unknown tags
if ( $GLOBALS['HIDE_UNKNOWN_TAGS'] === FALSE )
{
// User wants to display unknown tags
// Check if the Data is an ascii string
if ( $Exif_Tag['Data Type'] == 2 )
{
// This is a Ascii String field - add it preformatted to the output
$output_str .= "| " . $Exif_Tag['Tag Name'] . " | " . trim( $Exif_Tag['Text Value'] ) . " |
\n";
}
else
{
// Not an ASCII string - add it as is to the output
$output_str .= "| " . $Exif_Tag['Tag Name'] . " | " . trim( $Exif_Tag['Text Value'] ) . " |
\n";
}
}
}
}
}
// Close the table in the output
$output_str .= "
\n";
// Add the secondary output at the end of the main output
$output_str .= "$extra_IFD_str\n";
// Return the resulting html
return $output_str;
}
/******************************************************************************
* End of Function: interpret_IFD
******************************************************************************/
/******************************************************************************
*
* Function: get_IFD_Data_Type
*
* Description: Decodes an IFD field value from a binary data string, using
* information supplied about the data type and byte alignment of
* the stored data.
* This function should be used for all datatypes except ASCII strings
*
* Parameters: input_data - a binary data string containing the IFD value,
* must be exact length of the value
* data_type - a number representing the IFD datatype as per the
* TIFF 6.0 specification:
* 1 = Unsigned 8-bit Byte
* 2 = ASCII String
* 3 = Unsigned 16-bit Short
* 4 = Unsigned 32-bit Long
* 5 = Unsigned 2x32-bit Rational
* 6 = Signed 8-bit Byte
* 7 = Undefined
* 8 = Signed 16-bit Short
* 9 = Signed 32-bit Long
* 10 = Signed 2x32-bit Rational
* 11 = 32-bit Float
* 12 = 64-bit Double
* Byte_Align - Indicates the byte alignment of the data.
* MM = Motorola, MSB first, Big Endian
* II = Intel, LSB first, Little Endian
*
* Returns: output - the value of the data (string or numeric)
*
******************************************************************************/
function get_IFD_Data_Type( $input_data, $data_type, $Byte_Align )
{
// Check if this is a Unsigned Byte, Unsigned Short or Unsigned Long
if (( $data_type == 1 ) || ( $data_type == 3 ) || ( $data_type == 4 ))
{
// This is a Unsigned Byte, Unsigned Short or Unsigned Long
// Check the byte alignment to see if the bytes need tp be reversed
if ( $Byte_Align == "II" )
{
// This is in Intel format, reverse it
$input_data = strrev ( $input_data );
}
// Convert the binary string to a number and return it
return hexdec( bin2hex( $input_data ) );
}
// Check if this is a ASCII string type
elseif ( $data_type == 2 )
{
// Null terminated ASCII string(s)
// The input data may represent multiple strings, as the
// 'count' field represents the total bytes, not the number of strings
// Hence this should not be processed here, as it would have
// to return multiple values instead of a single value
echo "Error - ASCII Strings should not be processed in get_IFD_Data_Type
\n";
return "Error Should never get here"; //explode( "\x00", $input_data );
}
// Check if this is a Unsigned rational type
elseif ( $data_type == 5 )
{
// This is a Unsigned rational type
// Check the byte alignment to see if the bytes need to be reversed
if ( $Byte_Align == "MM" )
{
// Motorola MSB first byte aligment
// Unpack the Numerator and denominator and return them
return unpack( 'NNumerator/NDenominator', $input_data );
}
else
{
// Intel LSB first byte aligment
// Unpack the Numerator and denominator and return them
return unpack( 'VNumerator/VDenominator', $input_data );
}
}
// Check if this is a Signed Byte, Signed Short or Signed Long
elseif ( ( $data_type == 6 ) || ( $data_type == 8 ) || ( $data_type == 9 ) )
{
// This is a Signed Byte, Signed Short or Signed Long
// Check the byte alignment to see if the bytes need to be reversed
if ( $Byte_Align == "II" )
{
//Intel format, reverse the bytes
$input_data = strrev ( $input_data );
}
// Convert the binary string to an Unsigned number
$value = hexdec( bin2hex( $input_data ) );
// Convert to signed number
// Check if it is a Byte above 128 (i.e. a negative number)
if ( ( $data_type == 6 ) && ( $value > 128 ) )
{
// number should be negative - make it negative
return $value - 256;
}
// Check if it is a Short above 32767 (i.e. a negative number)
if ( ( $data_type == 8 ) && ( $value > 32767 ) )
{
// number should be negative - make it negative
return $value - 65536;
}
// Check if it is a Long above 2147483648 (i.e. a negative number)
if ( ( $data_type == 9 ) && ( $value > 2147483648 ) )
{
// number should be negative - make it negative
return $value - 4294967296;
}
// Return the signed number
return $value;
}
// Check if this is Undefined type
elseif ( $data_type == 7 )
{
// Custom Data - Do nothing
return $input_data;
}
// Check if this is a Signed Rational type
elseif ( $data_type == 10 )
{
// This is a Signed Rational type
// Signed Long not available with endian in unpack , use unsigned and convert
// Check the byte alignment to see if the bytes need to be reversed
if ( $Byte_Align == "MM" )
{
// Motorola MSB first byte aligment
// Unpack the Numerator and denominator
$value = unpack( 'NNumerator/NDenominator', $input_data );
}
else
{
// Intel LSB first byte aligment
// Unpack the Numerator and denominator
$value = unpack( 'VNumerator/VDenominator', $input_data );
}
// Convert the numerator to a signed number
// Check if it is above 2147483648 (i.e. a negative number)
if ( $value['Numerator'] > 2147483648 )
{
// number is negative
$value['Numerator'] -= 4294967296;
}
// Convert the denominator to a signed number
// Check if it is above 2147483648 (i.e. a negative number)
if ( $value['Denominator'] > 2147483648 )
{
// number is negative
$value['Denominator'] -= 4294967296;
}
// Return the Signed Rational value
return $value;
}
// Check if this is a Float type
elseif ( $data_type == 11 )
{
// IEEE 754 Float
// TODO - EXIF - IFD datatype Float not implemented yet
return "FLOAT NOT IMPLEMENTED YET";
}
// Check if this is a Double type
elseif ( $data_type == 12 )
{
// IEEE 754 Double
// TODO - EXIF - IFD datatype Double not implemented yet
return "DOUBLE NOT IMPLEMENTED YET";
}
else
{
// Error - Invalid Datatype
return "Invalid Datatype $data_type";
}
}
/******************************************************************************
* End of Function: get_IFD_Data_Type
******************************************************************************/
/******************************************************************************
*
* Function: put_IFD_Data_Type
*
* Description: Encodes an IFD field from a value to a binary data string, using
* information supplied about the data type and byte alignment of
* the stored data.
*
* Parameters: input_data - an IFD data value, numeric or string
* data_type - a number representing the IFD datatype as per the
* TIFF 6.0 specification:
* 1 = Unsigned 8-bit Byte
* 2 = ASCII String
* 3 = Unsigned 16-bit Short
* 4 = Unsigned 32-bit Long
* 5 = Unsigned 2x32-bit Rational
* 6 = Signed 8-bit Byte
* 7 = Undefined
* 8 = Signed 16-bit Short
* 9 = Signed 32-bit Long
* 10 = Signed 2x32-bit Rational
* 11 = 32-bit Float
* 12 = 64-bit Double
* Byte_Align - Indicates the byte alignment of the data.
* MM = Motorola, MSB first, Big Endian
* II = Intel, LSB first, Little Endian
*
* Returns: output - the packed binary string of the data
*
******************************************************************************/
function put_IFD_Data_Type( $input_data, $data_type, $Byte_Align )
{
// Process according to the datatype
switch ( $data_type )
{
case 1: // Unsigned Byte - return character as is
return chr($input_data);
break;
case 2: // ASCII String
// Return the string with terminating null
return $input_data . "\x00";
break;
case 3: // Unsigned Short
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the short and return
return pack( "v", $input_data );
}
else
{
// Motorola/Big Endian - pack the short and return
return pack( "n", $input_data );
}
break;
case 4: // Unsigned Long
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the long and return
return pack( "V", $input_data );
}
else
{
// Motorola/Big Endian - pack the long and return
return pack( "N", $input_data );
}
break;
case 5: // Unsigned Rational
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the two longs and return
return pack( "VV", $input_data['Numerator'], $input_data['Denominator'] );
}
else
{
// Motorola/Big Endian - pack the two longs and return
return pack( "NN", $input_data['Numerator'], $input_data['Denominator'] );
}
break;
case 6: // Signed Byte
// Check if number is negative
if ( $input_data < 0 )
{
// Number is negative - return signed character
return chr( $input_data + 256 );
}
else
{
// Number is positive - return character
return chr( $input_data );
}
break;
case 7: // Unknown - return as is
return $input_data;
break;
case 8: // Signed Short
// Check if number is negative
if ( $input_data < 0 )
{
// Number is negative - make signed value
$input_data = $input_data + 65536;
}
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the short and return
return pack( "v", $input_data );
}
else
{
// Motorola/Big Endian - pack the short and return
return pack( "n", $input_data );
}
break;
case 9: // Signed Long
// Check if number is negative
if ( $input_data < 0 )
{
// Number is negative - make signed value
$input_data = $input_data + 4294967296;
}
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the long and return
return pack( "v", $input_data );
}
else
{
// Motorola/Big Endian - pack the long and return
return pack( "n", $input_data );
}
break;
case 10: // Signed Rational
// Check if numerator is negative
if ( $input_data['Numerator'] < 0 )
{
// Number is numerator - make signed value
$input_data['Numerator'] = $input_data['Numerator'] + 4294967296;
}
// Check if denominator is negative
if ( $input_data['Denominator'] < 0 )
{
// Number is denominator - make signed value
$input_data['Denominator'] = $input_data['Denominator'] + 4294967296;
}
// Check byte alignment
if ( $Byte_Align == "II" )
{
// Intel/Little Endian - pack the two longs and return
return pack( "VV", $input_data['Numerator'], $input_data['Denominator'] );
}
else
{
// Motorola/Big Endian - pack the two longs and return
return pack( "NN", $input_data['Numerator'], $input_data['Denominator'] );
}
break;
case 11: // Float
// IEEE 754 Float
// TODO - EXIF - IFD datatype Float not implemented yet
return "FLOAT NOT IMPLEMENTED YET";
break;
case 12: // Double
// IEEE 754 Double
// TODO - EXIF - IFD datatype Double not implemented yet
return "DOUBLE NOT IMPLEMENTED YET";
break;
default:
// Error - Invalid Datatype
return "Invalid Datatype $data_type";
break;
}
// Shouldn't get here
return FALSE;
}
/******************************************************************************
* End of Function: put_IFD_Data_Type
******************************************************************************/
/******************************************************************************
*
* Function: get_IFD_value_as_text
*
* Description: Decodes an IFD field value from a binary data string, using
* information supplied about the data type and byte alignment of
* the stored data.
* This function should be used for all datatypes except ASCII strings
*
* Parameters: input_data - a binary data string containing the IFD value,
* must be exact length of the value
* data_type - a number representing the IFD datatype as per the
* TIFF 6.0 specification:
* 1 = Unsigned 8-bit Byte
* 2 = ASCII String
* 3 = Unsigned 16-bit Short
* 4 = Unsigned 32-bit Long
* 5 = Unsigned 2x32-bit Rational
* 6 = Signed 8-bit Byte
* 7 = Undefined
* 8 = Signed 16-bit Short
* 9 = Signed 32-bit Long
* 10 = Signed 2x32-bit Rational
* 11 = 32-bit Float
* 12 = 64-bit Double
* Byte_Align - Indicates the byte alignment of the data.
* MM = Motorola, MSB first, Big Endian
* II = Intel, LSB first, Little Endian
*
* Returns: output - the value of the data (string or numeric)
*
******************************************************************************/
function get_IFD_value_as_text( $Exif_Tag )
{
// Create a string to receive the output text
$output_str = "";
// Select Processing method according to the datatype
switch ($Exif_Tag['Data Type'])
{
case 1 : // Unsigned Byte
case 3 : // Unsigned Short
case 4 : // Unsigned Long
case 6 : // Signed Byte
case 8 : // Signed Short
case 9 : // Signed Long
// Cycle through each of the values for this tag
foreach ( $Exif_Tag['Data'] as $val )
{
// Check that this isn't the first value,
if ( $output_str != "" )
{
// This isn't the first value, Add a Comma and Newline to the output
$output_str .= ",\n";
}
// Add the Value to the output
$output_str .= $val;
}
break;
case 2 : // ASCII
// Append all the strings together, separated by Newlines
$output_str .= implode ( "\n", $Exif_Tag['Data']);
break;
case 5 : // Unsigned Rational
case 10: // Signed Rational
// Cycle through each of the values for this tag
foreach ( $Exif_Tag['Data'] as $val )
{
// Check that this isn't the first value,
if ( $output_str != "" )
{
// This isn't the first value, Add a Comma and Newline to the output
$output_str .= ",\n";
}
// Add the Full Value to the output
$output_str .= $val['Numerator'] ."/" . $val['Denominator'];
// Check if division by zero might be a problem
if ( $val['Denominator'] != 0 )
{
// Denominator is not zero, Add the Decimal Value to the output text
$output_str .= " (" . ($val['Numerator'] / $val['Denominator']) . ")";
}
}
break;
case 11: // Float
case 12: // Double
// TODO - EXIF - IFD datatype Double and Float not implemented yet
$output_str .= "Float and Double not implemented yet";
break;
case 7 : // Undefined
// Unless the User has asked to see the raw binary data, this
// type should not be displayed
// Check if the user has requested to see the binary data in hex
if ( $GLOBALS['SHOW_BINARY_DATA_HEX'] == TRUE)
{
// User has requested to see the binary data in hex
// Add the value in hex
$output_str .= "( " . strlen( $Exif_Tag['Data'] ) . " bytes of binary data ): " . bin2hex( $Exif_Tag['Data'] ) ;
}
// Check if the user has requested to see the binary data as is
else if ( $GLOBALS['SHOW_BINARY_DATA_TEXT'] == TRUE)
{
// User has requested to see the binary data as is
// Add the value as is
$output_str .= "( " . strlen( $Exif_Tag['Data'] ) . " bytes of binary data ): " . $Exif_Tag['Data'] ;
}
else
{
// User has NOT requested to see binary data,
// Add a message indicating the number of bytes to the output
$output_str .= "( " . strlen( $Exif_Tag['Data'] ) . " bytes of binary data ) " ;
}
break;
default :
// Error - Unknown IFD datatype
$output_str .= "Error - Exif tag data type (" . $Exif_Tag['Data Type'] .") is invalid";
break;
}
// Return the resulting text string
return $output_str;
}
/******************************************************************************
* End of Function: get_IFD_value_as_text
******************************************************************************/
/******************************************************************************
* Global Variable: IFD_Data_Sizes
*
* Contents: The sizes (in bytes) of each EXIF IFD Datatype, indexed by
* their datatype number
*
******************************************************************************/
$GLOBALS['IFD_Data_Sizes'] = array( 1 => 1, // Unsigned Byte
2 => 1, // ASCII String
3 => 2, // Unsigned Short
4 => 4, // Unsigned Long
5 => 8, // Unsigned Rational
6 => 1, // Signed Byte
7 => 1, // Undefined
8 => 2, // Signed Short
9 => 4, // Signed Long
10 => 8, // Signed Rational
11 => 4, // Float
12 => 8 ); // Double
/******************************************************************************
* End of Global Variable: IFD_Data_Sizes
******************************************************************************/
?>