<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                ///
//            or http://www.getid3.org                        ///
/////////////////////////////////////////////////////////////////
//                                                             //
// getid3.swf.php - part of getID3()                           //
// See getid3.readme.txt for more details                      //
//                                                             //
/////////////////////////////////////////////////////////////////

function getSWFHeaderFilepointer(&$fd, &$ThisFileInfo, $ReturnAllTagData=false) {
	$ThisFileInfo['fileformat']          = 'swf';
	$ThisFileInfo['video']['dataformat'] = 'swf';

	// http://www.openswf.org/spec/SWFfileformat.html

	fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);

	$SWFfileData = fread($fd, $ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']); // 8 + 2 + 2 + max(9) bytes NOT including Frame_Size RECT data

	$ThisFileInfo['swf']['header']['signature']   = substr($SWFfileData, 0, 3);
	switch ($ThisFileInfo['swf']['header']['signature']) {
		case 'FWS':
			$ThisFileInfo['swf']['header']['compressed'] = false;
			break;

		case 'CWS':
			$ThisFileInfo['swf']['header']['compressed'] = true;
			break;

		default:
			$ThisFileInfo['error'] .= "\n".'Expecting "FWS" or "CWS" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$ThisFileInfo['swf']['header']['signature'].'"';
			unset($ThisFileInfo['swf']);
			unset($ThisFileInfo['fileformat']);
			return false;
			break;
	}
	$ThisFileInfo['swf']['header']['version']      = LittleEndian2Int(substr($SWFfileData, 3, 1));
	$ThisFileInfo['swf']['header']['length']       = LittleEndian2Int(substr($SWFfileData, 4, 4));

	if ($ThisFileInfo['swf']['header']['compressed']) {

		if ($UncompressedFileData = @gzuncompress(substr($SWFfileData, 8))) {

			$SWFfileData = substr($SWFfileData, 0, 8).$UncompressedFileData;

		} else {

			$ThisFileInfo['error'] .= "\n".'Error decompressing compressed SWF data';
			return false;

		}

	}

	$FrameSizeBitsPerValue = (ord(substr($SWFfileData, 8, 1)) & 0xF8) >> 3;
	$FrameSizeDataLength   = ceil((5 + (4 * $FrameSizeBitsPerValue)) / 8);
	$FrameSizeDataString   = str_pad(decbin(ord(substr($SWFfileData, 8, 1)) & 0x07), 3, '0', STR_PAD_LEFT);
	for ($i = 1; $i < $FrameSizeDataLength; $i++) {
		$FrameSizeDataString .= str_pad(decbin(ord(substr($SWFfileData, 8 + $i, 1))), 8, '0', STR_PAD_LEFT);
	}
	list($X1, $X2, $Y1, $Y2) = explode("\n", wordwrap($FrameSizeDataString, $FrameSizeBitsPerValue, "\n", 1));
	$ThisFileInfo['swf']['header']['frame_width']  = Bin2Dec($X2);
	$ThisFileInfo['swf']['header']['frame_height'] = Bin2Dec($Y2);

	// http://www-lehre.informatik.uni-osnabrueck.de/~fbstark/diplom/docs/swf/Flash_Uncovered.htm
	// Next in the header is the frame rate, which is kind of weird.
	// It is supposed to be stored as a 16bit integer, but the first byte
	// (or last depending on how you look at it) is completely ignored.
	// Example: 0x000C  ->  0x0C  ->  12     So the frame rate is 12 fps.

	// Byte at (8 + $FrameSizeDataLength) is always zero and ignored
	$ThisFileInfo['swf']['header']['frame_rate']  = LittleEndian2Int(substr($SWFfileData,  9 + $FrameSizeDataLength, 1));
	$ThisFileInfo['swf']['header']['frame_count'] = LittleEndian2Int(substr($SWFfileData, 10 + $FrameSizeDataLength, 2));

	$ThisFileInfo['video']['frame_rate']         = $ThisFileInfo['swf']['header']['frame_rate'];
	$ThisFileInfo['video']['resolution_x']       = round($ThisFileInfo['swf']['header']['frame_width']  / 20);
	$ThisFileInfo['video']['resolution_y']       = round($ThisFileInfo['swf']['header']['frame_height'] / 20);
	$ThisFileInfo['video']['pixel_aspect_ratio'] = (float) 1;

	if (($ThisFileInfo['swf']['header']['frame_count'] > 0) && ($ThisFileInfo['swf']['header']['frame_rate'] > 0)) {
		$ThisFileInfo['playtime_seconds'] = $ThisFileInfo['swf']['header']['frame_count'] / $ThisFileInfo['swf']['header']['frame_rate'];
	}


	// SWF tags

	$CurrentOffset = 12 + $FrameSizeDataLength;
	$SWFdataLength = strlen($SWFfileData);

	while ($CurrentOffset < $SWFdataLength) {

		$TagIDTagLength = LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 2));
		$TagID     = ($TagIDTagLength & 0xFFFC) >> 6;
		$TagLength = ($TagIDTagLength & 0x003F);
		$CurrentOffset += 2;
		if ($TagLength == 0x3F) {
			$TagLength = LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 4));
			$CurrentOffset += 4;
		}

		unset($TagData);
		$TagData['offset'] = $CurrentOffset;
		$TagData['size']   = $TagLength;
		$TagData['id']     = $TagID;
		$TagData['data']   = substr($SWFfileData, $CurrentOffset, $TagLength);
		switch ($TagID) {
			case 0: // end of movie
				break 2;

			case 9: // Set background color
				//$ThisFileInfo['swf']['tags'][] = $TagData;
				$ThisFileInfo['swf']['bgcolor'] = strtoupper(str_pad(dechex(BigEndian2Int($TagData['data'])), 6, '0', STR_PAD_LEFT));
				break;

			default:
				if ($ReturnAllTagData) {
					$ThisFileInfo['swf']['tags'][] = $TagData;
				}
				break;
		}

		$CurrentOffset += $TagLength;
	}

	return true;
}

?>