public function Analyze()
{
$getid3 = $this->getid3;
// dependency
$getid3->include_module('tag.id3v1');
if ($getid3->option_tags_images) {
$getid3->include_module('lib.image_size');
}
// Overall tag structure:
// +-----------------------------+
// | Header (10 bytes) |
// +-----------------------------+
// | Extended Header |
// | (variable length, OPTIONAL) |
// +-----------------------------+
// | Frames (variable length) |
// +-----------------------------+
// | Padding |
// | (variable length, OPTIONAL) |
// +-----------------------------+
// | Footer (10 bytes, OPTIONAL) |
// +-----------------------------+
//
// Header
// ID3v2/file identifier "ID3"
// ID3v2 version $04 00
// ID3v2 flags (%ab000000 in v2.2, %abc00000 in v2.3, %abcd0000 in v2.4.x)
// ID3v2 size 4 * %0xxxxxxx
// shortcuts
$getid3->info['id3v2']['header'] = true;
$info_id3v2 =& $getid3->info['id3v2'];
$info_id3v2['flags'] = array();
$info_id3v2_flags =& $info_id3v2['flags'];
$this->fseek($this->option_starting_offset, SEEK_SET);
$header = $this->fread(10);
if (substr($header, 0, 3) == 'ID3' && strlen($header) == 10) {
$info_id3v2['majorversion'] = ord($header[3]);
$info_id3v2['minorversion'] = ord($header[4]);
// shortcut
$id3v2_major_version =& $info_id3v2['majorversion'];
} else {
unset($getid3->info['id3v2']);
return false;
}
if ($id3v2_major_version > 4) {
// this script probably won't correctly parse ID3v2.5.x and above (if it ever exists)
throw new getid3_exception('this script only parses up to ID3v2.4.x - this tag is ID3v2.' . $id3v2_major_version . '.' . $info_id3v2['minorversion']);
}
$id3_flags = ord($header[5]);
switch ($id3v2_major_version) {
case 2:
// %ab000000 in v2.2
$info_id3v2_flags['unsynch'] = (bool) ($id3_flags & 0x80);
// a - Unsynchronisation
$info_id3v2_flags['compression'] = (bool) ($id3_flags & 0x40);
// b - Compression
break;
case 3:
// %abc00000 in v2.3
$info_id3v2_flags['unsynch'] = (bool) ($id3_flags & 0x80);
// a - Unsynchronisation
$info_id3v2_flags['exthead'] = (bool) ($id3_flags & 0x40);
// b - Extended header
$info_id3v2_flags['experim'] = (bool) ($id3_flags & 0x20);
// c - Experimental indicator
break;
case 4:
// %abcd0000 in v2.4
$info_id3v2_flags['unsynch'] = (bool) ($id3_flags & 0x80);
// a - Unsynchronisation
$info_id3v2_flags['exthead'] = (bool) ($id3_flags & 0x40);
// b - Extended header
$info_id3v2_flags['experim'] = (bool) ($id3_flags & 0x20);
// c - Experimental indicator
$info_id3v2_flags['isfooter'] = (bool) ($id3_flags & 0x10);
// d - Footer present
break;
}
$info_id3v2['headerlength'] = getid3_lib::BigEndianSyncSafe2Int(substr($header, 6, 4)) + 10;
// length of ID3v2 tag in 10-byte header doesn't include 10-byte header length
$info_id3v2['tag_offset_start'] = $this->option_starting_offset;
$info_id3v2['tag_offset_end'] = $info_id3v2['tag_offset_start'] + $info_id3v2['headerlength'];
// Frames
// All ID3v2 frames consists of one frame header followed by one or more
// fields containing the actual information. The header is always 10
// bytes and laid out as follows:
//
// Frame ID $xx xx xx xx (four characters)
// Size 4 * %0xxxxxxx
// Flags $xx xx
$size_of_frames = $info_id3v2['headerlength'] - 10;
// not including 10-byte initial header
if (@$info_id3v2['exthead']['length']) {
$size_of_frames -= $info_id3v2['exthead']['length'] + 4;
}
if (@$info_id3v2_flags['isfooter']) {
$size_of_frames -= 10;
// footer takes last 10 bytes of ID3v2 header, after frame data, before audio
}
if ($size_of_frames > 0) {
$frame_data = $this->fread($size_of_frames);
// read all frames from file into $frame_data variable
// if entire frame data is unsynched, de-unsynch it now (ID3v2.3.x)
if (@$info_id3v2_flags['unsynch'] && $id3v2_major_version <= 3) {
$frame_data = str_replace("ÿ", "ÿ", $frame_data);
}
// [in ID3v2.4.0] Unsynchronisation [S:6.1] is done on frame level, instead
// of on tag level, making it easier to skip frames, increasing the streamability
// of the tag. The unsynchronisation flag in the header [S:3.1] indicates that
// there exists an unsynchronised frame, while the new unsynchronisation flag in
// the frame header [S:4.1.2] indicates unsynchronisation.
//$frame_data_offset = 10 + (@$info_id3v2['exthead']['length'] ? $info_id3v2['exthead']['length'] + 4 : 0); // how many bytes into the stream - start from after the 10-byte header (and extended header length+4, if present)
$frame_data_offset = 10;
// how many bytes into the stream - start from after the 10-byte header
// Extended Header
if (@$info_id3v2_flags['exthead']) {
$extended_header_offset = 0;
if ($id3v2_major_version == 3) {
// v2.3 definition:
//Extended header size $xx xx xx xx // 32-bit integer
//Extended Flags $xx xx
// %x0000000 %00000000 // v2.3
// x - CRC data present
//Size of padding $xx xx xx xx
$info_id3v2['exthead']['length'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 4), 0);
$extended_header_offset += 4;
$info_id3v2['exthead']['flag_bytes'] = 2;
$info_id3v2['exthead']['flag_raw'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, $info_id3v2['exthead']['flag_bytes']));
$extended_header_offset += $info_id3v2['exthead']['flag_bytes'];
$info_id3v2['exthead']['flags']['crc'] = (bool) ($info_id3v2['exthead']['flag_raw'] & 0x8000);
$info_id3v2['exthead']['padding_size'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 4));
$extended_header_offset += 4;
if ($info_id3v2['exthead']['flags']['crc']) {
$info_id3v2['exthead']['flag_data']['crc'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 4));
$extended_header_offset += 4;
}
$extended_header_offset += $info_id3v2['exthead']['padding_size'];
} elseif ($id3v2_major_version == 4) {
// v2.4 definition:
//Extended header size 4 * %0xxxxxxx // 28-bit synchsafe integer
//Number of flag bytes $01
//Extended Flags $xx
// %0bcd0000 // v2.4
// b - Tag is an update
// Flag data length $00
// c - CRC data present
// Flag data length $05
// Total frame CRC 5 * %0xxxxxxx
// d - Tag restrictions
// Flag data length $01
$info_id3v2['exthead']['length'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 4), 1);
$extended_header_offset += 4;
$info_id3v2['exthead']['flag_bytes'] = 1;
$info_id3v2['exthead']['flag_raw'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, $info_id3v2['exthead']['flag_bytes']));
$extended_header_offset += $info_id3v2['exthead']['flag_bytes'];
$info_id3v2['exthead']['flags']['update'] = (bool) ($info_id3v2['exthead']['flag_raw'] & 0x4000);
$info_id3v2['exthead']['flags']['crc'] = (bool) ($info_id3v2['exthead']['flag_raw'] & 0x2000);
$info_id3v2['exthead']['flags']['restrictions'] = (bool) ($info_id3v2['exthead']['flag_raw'] & 0x1000);
if ($info_id3v2['exthead']['flags']['crc']) {
$info_id3v2['exthead']['flag_data']['crc'] = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 5), 1);
$extended_header_offset += 5;
}
if ($info_id3v2['exthead']['flags']['restrictions']) {
// %ppqrrstt
$restrictions_raw = getid3_lib::BigEndian2Int(substr($frame_data, $extended_header_offset, 1));
$extended_header_offset += 1;
$info_id3v2['exthead']['flags']['restrictions']['tagsize'] = ($restrictions_raw && 0xc0) >> 6;
// p - Tag size restrictions
$info_id3v2['exthead']['flags']['restrictions']['textenc'] = ($restrictions_raw && 0x20) >> 5;
// q - Text encoding restrictions
$info_id3v2['exthead']['flags']['restrictions']['textsize'] = ($restrictions_raw && 0x18) >> 3;
// r - Text fields size restrictions
$info_id3v2['exthead']['flags']['restrictions']['imgenc'] = ($restrictions_raw && 0x4) >> 2;
// s - Image encoding restrictions
$info_id3v2['exthead']['flags']['restrictions']['imgsize'] = ($restrictions_raw && 0x3) >> 0;
// t - Image size restrictions
}
}
$frame_data_offset += $extended_header_offset;
$frame_data = substr($frame_data, $extended_header_offset);
}
// end extended header
while (isset($frame_data) && strlen($frame_data) > 0) {
// cycle through until no more frame data is left to parse
if (strlen($frame_data) <= ($id3v2_major_version == 2 ? 6 : 10)) {
// insufficient room left in ID3v2 header for actual data - must be padding
$info_id3v2['padding']['start'] = $frame_data_offset;
$info_id3v2['padding']['length'] = strlen($frame_data);
$info_id3v2['padding']['valid'] = true;
for ($i = 0; $i < $info_id3v2['padding']['length']; $i++) {
if ($frame_data[$i] != "") {
$info_id3v2['padding']['valid'] = false;
$info_id3v2['padding']['errorpos'] = $info_id3v2['padding']['start'] + $i;
$getid3->warning('Invalid ID3v2 padding found at offset ' . $info_id3v2['padding']['errorpos'] . ' (the remaining ' . ($info_id3v2['padding']['length'] - $i) . ' bytes are considered invalid)');
break;
}
}
break;
// skip rest of ID3v2 header
}
if ($id3v2_major_version == 2) {
// Frame ID $xx xx xx (three characters)
// Size $xx xx xx (24-bit integer)
// Flags $xx xx
$frame_header = substr($frame_data, 0, 6);
// take next 6 bytes for header
$frame_data = substr($frame_data, 6);
// and leave the rest in $frame_data
$frame_name = substr($frame_header, 0, 3);
$frame_size = getid3_lib::BigEndian2Int(substr($frame_header, 3, 3));
$frame_flags = 0;
// not used for anything in ID3v2.2, just set to avoid E_NOTICEs
} elseif ($id3v2_major_version > 2) {
// Frame ID $xx xx xx xx (four characters)
// Size $xx xx xx xx (32-bit integer in v2.3, 28-bit synchsafe in v2.4+)
// Flags $xx xx
$frame_header = substr($frame_data, 0, 10);
// take next 10 bytes for header
$frame_data = substr($frame_data, 10);
// and leave the rest in $frame_data
$frame_name = substr($frame_header, 0, 4);
if ($id3v2_major_version == 3) {
$frame_size = getid3_lib::BigEndian2Int(substr($frame_header, 4, 4));
// 32-bit integer
} else {
// ID3v2.4+
$frame_size = getid3_lib::BigEndianSyncSafe2Int(substr($frame_header, 4, 4));
// 32-bit synchsafe integer (28-bit value)
}
if ($frame_size < strlen($frame_data) + 4) {
$nextFrameID = substr($frame_data, $frame_size, 4);
if (getid3_id3v2::IsValidID3v2FrameName($nextFrameID, $id3v2_major_version)) {
// next frame is OK
} elseif ($frame_name == "" . 'MP3' || $frame_name == "" . 'MP' || $frame_name == ' MP3' || $frame_name == 'MP3e') {
// MP3ext known broken frames - "ok" for the purposes of this test
} elseif ($id3v2_major_version == 4 && getid3_id3v2::IsValidID3v2FrameName(substr($frame_data, getid3_lib::BigEndian2Int(substr($frame_header, 4, 4)), 4), 3)) {
$getid3->warning('ID3v2 tag written as ID3v2.4, but with non-synchsafe integers (ID3v2.3 style). Older versions of (Helium2; iTunes) are known culprits of this. Tag has been parsed as ID3v2.3');
$id3v2_major_version = 3;
$frame_size = getid3_lib::BigEndian2Int(substr($frame_header, 4, 4));
// 32-bit integer
}
}
$frame_flags = getid3_lib::BigEndian2Int(substr($frame_header, 8, 2));
}
if ($id3v2_major_version == 2 && $frame_name == "" || $frame_name == "") {
// padding encountered
$info_id3v2['padding']['start'] = $frame_data_offset;
$info_id3v2['padding']['length'] = strlen($frame_header) + strlen($frame_data);
$info_id3v2['padding']['valid'] = true;
$len = strlen($frame_data);
for ($i = 0; $i < $len; $i++) {
if ($frame_data[$i] != "") {
$info_id3v2['padding']['valid'] = false;
$info_id3v2['padding']['errorpos'] = $info_id3v2['padding']['start'] + $i;
$getid3->warning('Invalid ID3v2 padding found at offset ' . $info_id3v2['padding']['errorpos'] . ' (the remaining ' . ($info_id3v2['padding']['length'] - $i) . ' bytes are considered invalid)');
break;
}
}
break;
// skip rest of ID3v2 header
}
if ($frame_name == 'COM ') {
$getid3->warning('error parsing "' . $frame_name . '" (' . $frame_data_offset . ' bytes into the ID3v2.' . $id3v2_major_version . ' tag). (ERROR: IsValidID3v2FrameName("' . str_replace("", ' ', $frame_name) . '", ' . $id3v2_major_version . '))). [Note: this particular error has been known to happen with tags edited by iTunes (versions "X v2.0.3", "v3.0.1" are known-guilty, probably others too)]');
$frame_name = 'COMM';
}
if ($frame_size <= strlen($frame_data) && getid3_id3v2::IsValidID3v2FrameName($frame_name, $id3v2_major_version)) {
unset($parsed_frame);
$parsed_frame['frame_name'] = $frame_name;
$parsed_frame['frame_flags_raw'] = $frame_flags;
$parsed_frame['data'] = substr($frame_data, 0, $frame_size);
$parsed_frame['datalength'] = (int) $frame_size;
$parsed_frame['dataoffset'] = $frame_data_offset;
$this->ParseID3v2Frame($parsed_frame);
$info_id3v2[$frame_name][] = $parsed_frame;
$frame_data = substr($frame_data, $frame_size);
} else {
// invalid frame length or FrameID
if ($frame_size <= strlen($frame_data)) {
if (getid3_id3v2::IsValidID3v2FrameName(substr($frame_data, $frame_size, 4), $id3v2_major_version)) {
// next frame is valid, just skip the current frame
$frame_data = substr($frame_data, $frame_size);
$getid3->warning('Next ID3v2 frame is valid, skipping current frame.');
} else {
// next frame is invalid too, abort processing
throw new getid3_exception('Next ID3v2 frame is also invalid, aborting processing.');
}
} elseif ($frame_size == strlen($frame_data)) {
// this is the last frame, just skip
$getid3->warning('This was the last ID3v2 frame.');
} else {
// next frame is invalid too, abort processing
$frame_data = null;
$getid3->warning('Invalid ID3v2 frame size, aborting.');
}
if (!getid3_id3v2::IsValidID3v2FrameName($frame_name, $id3v2_major_version)) {
switch ($frame_name) {
case "" . 'MP':
case "" . 'MP3':
case ' MP3':
case 'MP3e':
case "" . 'MP':
case ' MP':
case 'MP3':
$getid3->warning('error parsing "' . $frame_name . '" (' . $frame_data_offset . ' bytes into the ID3v2.' . $id3v2_major_version . ' tag). (ERROR: !IsValidID3v2FrameName("' . str_replace("", ' ', $frame_name) . '", ' . $id3v2_major_version . '))). [Note: this particular error has been known to happen with tags edited by "MP3ext (www.mutschler.de/mp3ext/)"]');
break;
default:
$getid3->warning('error parsing "' . $frame_name . '" (' . $frame_data_offset . ' bytes into the ID3v2.' . $id3v2_major_version . ' tag). (ERROR: !IsValidID3v2FrameName("' . str_replace("", ' ', $frame_name) . '", ' . $id3v2_major_version . '))).');
break;
}
} elseif ($frame_size > strlen(@$frame_data)) {
throw new getid3_exception('error parsing "' . $frame_name . '" (' . $frame_data_offset . ' bytes into the ID3v2.' . $id3v2_major_version . ' tag). (ERROR: $frame_size (' . $frame_size . ') > strlen($frame_data) (' . strlen($frame_data) . ')).');
} else {
throw new getid3_exception('error parsing "' . $frame_name . '" (' . $frame_data_offset . ' bytes into the ID3v2.' . $id3v2_major_version . ' tag).');
}
}
$frame_data_offset += $frame_size + ($id3v2_major_version == 2 ? 6 : 10);
}
}
// Footer
// The footer is a copy of the header, but with a different identifier.
// ID3v2 identifier "3DI"
// ID3v2 version $04 00
// ID3v2 flags %abcd0000
// ID3v2 size 4 * %0xxxxxxx
if (isset($info_id3v2_flags['isfooter']) && $info_id3v2_flags['isfooter']) {
$footer = fread($getid3->fp, 10);
if (substr($footer, 0, 3) == '3DI') {
$info_id3v2['footer'] = true;
$info_id3v2['majorversion_footer'] = ord($footer[3]);
$info_id3v2['minorversion_footer'] = ord($footer[4]);
}
if ($info_id3v2['majorversion_footer'] <= 4) {
$id3_flags = ord($footer[5]);
$info_id3v2_flags['unsynch_footer'] = (bool) ($id3_flags & 0x80);
$info_id3v2_flags['extfoot_footer'] = (bool) ($id3_flags & 0x40);
$info_id3v2_flags['experim_footer'] = (bool) ($id3_flags & 0x20);
$info_id3v2_flags['isfooter_footer'] = (bool) ($id3_flags & 0x10);
$info_id3v2['footerlength'] = getid3_lib::BigEndianSyncSafe2Int(substr($footer, 6, 4));
}
}
// end footer
if (isset($info_id3v2['comments']['genre'])) {
foreach ($info_id3v2['comments']['genre'] as $key => $value) {
unset($info_id3v2['comments']['genre'][$key]);
$info_id3v2['comments'] = getid3_id3v2::array_merge_noclobber($info_id3v2['comments'], getid3_id3v2::ParseID3v2GenreString($value));
}
}
if (isset($info_id3v2['comments']['track'])) {
foreach ($info_id3v2['comments']['track'] as $key => $value) {
if (strstr($value, '/')) {
list($info_id3v2['comments']['track'][$key], $info_id3v2['comments']['totaltracks'][$key]) = explode('/', $info_id3v2['comments']['track'][$key]);
}
}
}
// Use year from recording time if year not set
if (!isset($info_id3v2['comments']['year']) && ereg('^([0-9]{4})', @$info_id3v2['comments']['recording_time'][0], $matches)) {
$info_id3v2['comments']['year'] = array($matches[1]);
}
// Set avdataoffset
$getid3->info['avdataoffset'] = $info_id3v2['headerlength'];
if (isset($info_id3v2['footer'])) {
$getid3->info['avdataoffset'] += 10;
}
return true;
}
