function Float2String($floatvalue, $bits)
{
// http://www.scri.fsu.edu/~jac/MAD3401/Backgrnd/ieee-expl.html
switch ($bits) {
case 32:
$exponentbits = 8;
$fractionbits = 23;
break;
case 64:
$exponentbits = 11;
$fractionbits = 52;
break;
default:
return false;
break;
}
if ($floatvalue >= 0) {
$signbit = '0';
} else {
$signbit = '1';
}
$normalizedbinary = NormalizeBinaryPoint(Float2BinaryDecimal($floatvalue), $fractionbits);
$biasedexponent = pow(2, $exponentbits - 1) - 1 + $normalizedbinary['exponent'];
// (127 or 1023) +/- exponent
$exponentbitstring = str_pad(decbin($biasedexponent), $exponentbits, '0', STR_PAD_LEFT);
$fractionbitstring = str_pad(substr($normalizedbinary['normalized'], 2), $fractionbits, '0', STR_PAD_RIGHT);
return BigEndian2String(Bin2Dec($signbit . $exponentbitstring . $fractionbitstring), $bits % 8, false);
}
function Float2String($floatvalue, $bits)
{
// http://www.scri.fsu.edu/~jac/MAD3401/Backgrnd/ieee-expl.html
if ($bits != 32 && $bits != 64) {
return FALSE;
} else {
if ($bits == 32) {
$exponentbits = 8;
$fractionbits = 23;
} else {
if ($bits == 64) {
$exponentbits = 11;
$fractionbits = 52;
}
}
}
if ($floatvalue >= 0) {
$signbit = '0';
} else {
$signbit = '1';
}
$normalizedbinary = NormalizeBinaryPoint(Float2BinaryDecimal($floatvalue), $fractionbits);
$biasedexponent = pow(2, $exponentbits - 1) - 1 + $normalizedbinary['exponent'];
// (127 or 1023) +/- exponent
$exponentbitstring = str_pad(decbin($biasedexponent), $exponentbits, '0', STR_PAD_LEFT);
$fractionbitstring = str_pad(substr($normalizedbinary['normalized'], 2), $fractionbits, '0', STR_PAD_RIGHT);
return BigEndian2String(Bin2Dec($signbit . $exponentbitstring . $fractionbitstring), $bits % 8, FALSE);
}
function GenerateID3v2Tag($data, $majorversion = 4, $minorversion = 0, $paddedlength = 0, $extendedheader = '', $footer = FALSE, $showerrors = TRUE, $noerrorsonly = TRUE)
{
ID3v2FrameIsAllowed(NULL, '', '');
// clear static array in case this isn't the first call to GenerateID3v2Tag()
if (is_array($data)) {
if (is_array($extendedheader)) {
// not supported yet
}
foreach ($data as $frame_name => $frame_rawinputdata) {
if (!is_array($frame_rawinputdata[0])) {
// force everything to be arrayed so only one processing loop
$frame_rawinputdata = array($frame_rawinputdata);
}
foreach ($frame_rawinputdata as $irrelevantindex => $frame_inputdata) {
if (IsValidID3v2FrameName($frame_name, $majorversion)) {
unset($frame_length);
unset($frame_flags);
$frame_data = FALSE;
if (ID3v2FrameIsAllowed($frame_name, $frame_inputdata, $majorversion, $showerrors)) {
if ($frame_data = GenerateID3v2FrameData($frame_name, $frame_inputdata, $majorversion, $showerrors)) {
if ($majorversion >= 4) {
// frame-level unsynchronization
$FrameUnsynchronisation = FALSE;
$unsynchdata = Unsynchronise($frame_data);
if (strlen($unsynchdata) != strlen($frame_data)) {
// unsynchronization needed
$FrameUnsynchronisation = TRUE;
$frame_data = $unsynchdata;
if (isset($TagUnsynchronisation) && $TagUnsynchronisation === FALSE) {
// only set to true if ALL frames are unsynchronised
} else {
$TagUnsynchronisation = TRUE;
}
} else {
if (isset($TagUnsynchronisation)) {
$TagUnsynchronisation = FALSE;
}
}
unset($unsynchdata);
$frame_length = BigEndian2String(strlen($frame_data), 4, TRUE);
} else {
$frame_length = BigEndian2String(strlen($frame_data), 4, FALSE);
}
$frame_flags = GenerateID3v2FrameFlags($majorversion, ID3v2FrameFlagsLookupTagAlter($frame_name, $majorversion), ID3v2FrameFlagsLookupFileAlter($frame_name, $majorversion), FALSE, FALSE, FALSE, FALSE, $FrameUnsynchronisation, FALSE);
}
} else {
if ($showerrors) {
echo 'Frame "' . $frame_name . '" is NOT allowed<BR>';
}
}
if ($frame_data === FALSE) {
if ($showerrors) {
echo 'GenerateID3v2FrameData() failed for "' . $frame_name . '"<BR>';
echo 'Error generated in getID3() v' . GETID3VERSION . '<BR>';
}
if ($noerrorsonly) {
return FALSE;
} else {
unset($frame_name);
}
}
} else {
// ignore any invalid frame names, including 'title', 'header', etc
unset($frame_name);
unset($frame_length);
unset($frame_flags);
unset($frame_data);
}
$tagstring .= $frame_name . $frame_length . $frame_flags . $frame_data;
}
}
if ($footer) {
if ($showerrors) {
echo 'Footer not supported (yet)<BR>';
}
return FALSE;
}
//echo number_format(strlen($tagstring));
if ($majorversion <= 3) {
// tag-level unsynchronization
$unsynchdata = Unsynchronise($tagstring);
if (strlen($unsynchdata) != strlen($tagstring)) {
// unsynchronization needed
$TagUnsynchronisation = TRUE;
$tagstring = $unsynchdata;
}
}
//echo ' - '.number_format(strlen($tagstring)).'<BR>';
if (!$footer && $paddedlength > strlen($tagstring) + ID3v2HeaderLength($id3info['majorversion'])) {
// pad up to $paddedlength bytes if unpadded tag is shorter than $paddedlength
// "Furthermore it MUST NOT have any padding when a tag footer is added to the tag."
$tagstring .= @str_repeat(chr(0), $paddedlength - strlen($tagstring));
}
if (substr($tagstring, strlen($tagstring) - 1, 1) == chr(255)) {
// special unsynchronization case:
// if last byte == $FF then appended a $00
$TagUnsynchronisation = TRUE;
$tagstring .= chr(0);
}
$tagheader = 'ID3';
$tagheader .= chr($majorversion);
$tagheader .= chr($minorversion);
$tagheader .= GenerateID3v2TagFlags($majorversion, $TagUnsynchronisation, FALSE, (bool) $extendedheader, FALSE, $footer);
$tagheader .= BigEndian2String(strlen($tagstring), 4, TRUE);
return $tagheader . $tagstring;
} else {
return FALSE;
}
}
function GenerateRealTag()
{
$RealCONT = "";
// object version
$RealCONT .= BigEndian2String(strlen(@$this->tag_data['title']), 4);
$RealCONT .= @$this->tag_data['title'];
$RealCONT .= BigEndian2String(strlen(@$this->tag_data['artist']), 4);
$RealCONT .= @$this->tag_data['artist'];
$RealCONT .= BigEndian2String(strlen(@$this->tag_data['copyright']), 4);
$RealCONT .= @$this->tag_data['copyright'];
$RealCONT .= BigEndian2String(strlen(@$this->tag_data['comment']), 4);
$RealCONT .= @$this->tag_data['comment'];
if ($this->paddedlength > strlen($RealCONT) + 8) {
$RealCONT .= str_repeat("", $this->paddedlength - strlen($RealCONT) - 8);
}
$RealCONT = 'CONT' . BigEndian2String(strlen($RealCONT) + 8, 4) . $RealCONT;
// CONT chunk identifier + chunk length
return $RealCONT;
}
