PHP経由で添付ファイル付きのメールを送信する方法

<?
class CMailFile { 
	var $subject; 
	var $addr_to; 
	var $text_body; 
	var $text_encoded; 
	var $mime_headers; 
	var $mime_boundary = "--==================_846811060==_"; 
	var $smtp_headers; 
	
	function CMailFile($subject,$to,$from,$msg,$filename,$downfilename,$mimetype = "application/octet-stream",$mime_filename = false) { 
		$this->subject = $subject; 		
		$this->addr_to = $to; 		
		$this->smtp_headers = $this->write_smtpheaders($from);
		$this->text_body = $this->write_body($msg);
		$this->text_encoded = $this->attach_file($filename,$downfilename,$mimetype,$mime_filename);
		$this->mime_headers = $this->write_mimeheaders($filename, $mime_filename);
	} 
	function attach_file($filename,$downfilename,$mimetype,$mime_filename) {
		$encoded = $this->encode_file($filename);
		if ($mime_filename) $filename = $mime_filename;
		$out = "--" . $this->mime_boundary . "\n";
		$out = $out . "Content-type: " . $mimetype . "; name=\"$filename\";\n";
		$out = $out . "Content-Transfer-Encoding: base64\n";
		$out = $out . "Content-disposition: attachment; filename=\"$downfilename\"\n\n";
		$out = $out . $encoded . "\n";
		$out = $out . "--" . $this->mime_boundary . "--" . "\n";
		return $out;
	} 
	function encode_file($sourcefile) { 
		if (is_readable($sourcefile)) { 
			$fd = fopen($sourcefile, "r"); 
			$contents = fread($fd, filesize($sourcefile)); 
			$encoded = chunk_split(base64_encode($contents)); 
			fclose($fd); 
		} 
		return $encoded; 
	} 
	function sendfile() { 	
		$headers = $this->smtp_headers . $this->mime_headers; 
		$message = $this->text_body . $this->text_encoded; 
		mail($this->addr_to,$this->subject,$message,$headers); 
	} 
	function write_body($msgtext) { 
		$out = "--" . $this->mime_boundary . "\n"; 
		$out = $out . "Content-Type: text/plain; charset=\"us-ascii\"\n\n"; 
		$out = $out . $msgtext . "\n"; 
		return $out; 
	} 
	function write_mimeheaders($filename, $mime_filename) { 
		if ($mime_filename) $filename = $mime_filename; 
		$out = "MIME-version: 1.0\n"; 
		$out = $out . "Content-type: multipart/mixed; "; 
		$out = $out . "boundary=\"$this->mime_boundary\"\n"; 
		$out = $out . "Content-transfer-encoding: 7BIT\n"; 
		$out = $out . "X-attachments: $filename;\n\n"; 
		return $out; 
	} 
	function write_smtpheaders($addr_from) { 
		$out = "From: $addr_from\n"; 
		$out = $out . "Reply-To: $addr_from\n"; 
		$out = $out . "X-Mailer: PHP3\n"; 
		$out = $out . "X-Sender: $addr_from\n"; 
		return $out; 
	} 
} 
/*用法 - 例如:mimetype 为 "image/gif" 
	$mailfile = new CMailFile($subject,$sendto,$replyto,$message,$filename,$mimetype); 
	$mailfile->sendfile(); 
	$subject -- 主题 
	$sendto -- 收信人地址 
	$replyto -- 回复地址 
	$message -- 信件内容 
	$filename -- 附件文件名 
	$downfilename -- 下載的文件名
	$mimetype -- mime类型
*/
?>

<?php
	require_once(&#39;emailclass.php&#39;);
	//发送邮件
	
	//主題
	$subject = "test send email";
	//收件人
	$sendto = &#39;abc@163.com&#39;;
	
	//發件人
	$replyto = &#39;cdf@163.com&#39;;
	
	//內容
	$message = "test send email content";
	
	//附件
	$filename = &#39;test.jpg&#39;;
	
	//附件類別
	$mimetype = "image/jpeg";
	$mailfile = new CMailFile($subject,$sendto,$replyto,$message,$filename,$excelname,$mimetype); 
	$mailfile->sendfile();
?>