function get_Photoshop_IRB($jpeg_header_data)
{
// Photoshop Image Resource blocks can span several JPEG APP13 segments, so we need to join them up if there are more than one
$joined_IRB = "";
//Cycle through the header segments
for ($i = 0; $i < count($jpeg_header_data); $i++) {
// If we find an APP13 header,
if (strcmp($jpeg_header_data[$i]['SegName'], "APP13") == 0) {
// And if it has the photoshop label,
if (strncmp($jpeg_header_data[$i]['SegData'], "Photoshop 3.0", 14) == 0) {
// join it to the other previous IRB data
$joined_IRB .= substr($jpeg_header_data[$i]['SegData'], 14);
}
}
}
// If there was some Photoshop IRB information found,
if ($joined_IRB != "") {
// Found a Photoshop Image Resource Block - extract it.
// Change: Moved code into unpack_Photoshop_IRB_Data to allow TIFF reading as of 1.11
return unpack_Photoshop_IRB_Data($joined_IRB);
} else {
// No Photoshop IRB found
return FALSE;
}
}
function read_IFD_universal($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 "<p>Error: huge number of EXIF entries - EXIF is probably Corrupted</p>\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 * $No_Entries) {
// Couldn't read the IFD Data properly, Some Casio files have no Next IFD pointer, hence cause this error
echo "<p>Error: EXIF Corrupted</p>\n";
return array(FALSE, 0);
}
// Last 4 bytes of a standard IFD are the offset to the next IFD
// Some NON-Standard IFD implementations do not have this, hence causing problems if it is read
// If the Next IFD pointer has been requested to be read,
if ($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 "<p>Error: huge EXIF data count - EXIF is probably Corrupted</p>\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("", $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;
}
// Change: Check for embedded XMP as of version 1.11
// Check if this is a XMP Record within the EXIF IFD
if (($Tag_Definitions_Name == "EXIF" || $Tag_Definitions_Name == "TIFF") && $Tag_No == 700) {
// This is a XMP Record, interpret it and put result in the data for this entry
$OutputArray[$Tag_No]['Data'] = read_XMP_array_from_text($DataStr);
$OutputArray[$Tag_No]['Decoded'] = TRUE;
}
// Change: Check for embedded IRB as of version 1.11
// Check if this is a Photoshop IRB Record within the EXIF IFD
if (($Tag_Definitions_Name == "EXIF" || $Tag_Definitions_Name == "TIFF") && $Tag_No == 34377) {
// This is a Photoshop IRB Record, interpret it and put result in the data for this entry
$OutputArray[$Tag_No]['Data'] = unpack_Photoshop_IRB_Data($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 == 0x4 && array_key_exists(0x3, $OutputArray) || $Tag_No == 0x3 && array_key_exists(0x4, $OutputArray)) && $Tag_Definitions_Name == "Casio Type 2") {
// Seek to the start of the thumbnail using the offset entry
fseek($filehnd, $Tiff_offset + $OutputArray[0x4]['Data'][0]);
// Read the thumbnail data, and replace the offset data with the thumbnail
$OutputArray[0x4]['Data'] = network_safe_fread($filehnd, $OutputArray[0x3]['Data'][0]);
}
// Minolta Thumbnail
// Check that both the thumbnail length and offset entries have been processed,
// and that this is one of them
if (($Tag_No == 0x88 && array_key_exists(0x89, $OutputArray) || $Tag_No == 0x89 && array_key_exists(0x88, $OutputArray)) && $Tag_Definitions_Name == "Olympus") {
// Seek to the start of the thumbnail using the offset entry
fseek($filehnd, $Tiff_offset + $OutputArray[0x88]['Data'][0]);
// Read the thumbnail data, and replace the offset data with the thumbnail
$OutputArray[0x88]['Data'] = network_safe_fread($filehnd, $OutputArray[0x89]['Data'][0]);
// Sometimes the minolta thumbnail data is empty (or the offset is corrupt, which results in the same thing)
// Check if the thumbnail data exists
if ($OutputArray[0x88]['Data'] != "") {
// Thumbnail exists
// Minolta Thumbnails are missing their first 0xFF for some reason,
// which is replaced with some weird character, so fix this
$OutputArray[0x88]['Data'][0] = "ÿ";
} else {
// Thumbnail doesnt exist - make it obvious
$OutputArray[0x88]['Data'] = FALSE;
}
}
}
// Return the array of IFD entries and the offset to the next IFD
return array($OutputArray, $Next_Offset);
}
