关于php支持分块与断点续传文件下载功能代码

$dowmFile = dirname ( __FILE__ ) . ‘/Nokia – Always Here.mp3′; //要下载的文件，绝对或相对 
$dowmName = ‘Nokia – Always Here.mp3′; 
ob_start (); 
getlocalfile ( $dowmFile, $dowmName ); 
flush (); 
ob_flush (); 
function getlocalfile($fname, $filename = ”) { 
$fsize = filesize ( $fname ); 
header ( ‘Cache-Control: public' ); 
header ( ‘Pragma: public' ); 
header ( ‘Accept-Ranges: bytes' ); 
header ( ‘Connection: close' ); 
header ( ‘Content-Type: ‘ . MIMEType ( $fname ) ); 
//header(‘Content-Type: application/octet-stream'); 
if (isset ( $filename {0} )) { 
header ( ‘Content-Disposition: attachment;filename=' . $filename ); 
} 
if ($fp = @fopen ( $fname, ‘rb' )) { 
$start = 0; 
$end = $fsize; 
$isRange = isset ( $_SERVER ['HTTP_RANGE'] ) && ($_SERVER ['HTTP_RANGE'] != ”); 
if ($isRange) { 
preg_match ( ‘/^bytes=([0-9]*)-([0-9]*)$/i', $_SERVER ['HTTP_RANGE'], $match ); 
$start = $match [1]; 
$end = $match [2]; 
$isset_start = isset ( $start {0} ); 
$isset_end = isset ( $end {0} ); 
if ($isset_start && $isset_end) { 
//分块下载 
if ($start >= $fsize || $start < 0 || $start > $end) { 
$start = 0; 
$end = $fsize; 
} else if ($end >= $fsize) { 
$end = $fsize – $start; 
} else { 
$end -= $start – 1; 
} 
} else if ($isset_start && ! $isset_end) { 
//指定位置到结束 
if ($start >= $fsize || $start < 0) { 
$start = 0; 
$end = $fsize; 
} else { 
$end = $fsize – $start; 
} 
} else if (! $isset_start && $isset_end) { 
//最后n个字节 
$end = $end > $fsize ? $fsize : $end; 
$start = $fsize – $end; 
} else { 
$start = 0; 
$end = $fsize; 
} 
} 
if ($isRange) { 
fseek ( $fp, $start ); 
header ( ‘HTTP/1.1 206 Partial Content' ); 
header ( ‘Content-Length: ‘ . $end ); 
header ( ‘Content-Ranges: bytes ‘ . $start . ‘-' . ($end + $start – 1) . ‘/' . $fsize ); 
} else { 
header ( ‘Content-Length: ‘ . $fsize ); 
} 
if (function_exists ( ‘fpassthru' ) && ($end + $start) == $fsize) { 
fpassthru ( $fp ); 
} else { 
echo fread ( $fp, $end ); 
} 
} else { 
header ( ‘Content-Length: ‘ . $fsize ); 
readfile ( $fname ); 
} 
//@header(“Content-Type: “.mime_content_type($fname)); 
} 
function MIMEType($fname) { 
$fileSuffix = strtolower ( substr ( $fname, strrpos ( $fname, ‘.' ) + 1 ) ); 
switch ($fileSuffix) { 
case ‘avi' : 
return ‘video/msvideo'; 
case ‘wmv' : 
return ‘video/x-ms-wmv'; 
case ‘txt' : 
return ‘text/plain'; 
case ‘htm' : 
case ‘html' : 
case ‘php' : 
return ‘text/html'; 
case ‘css' : 
return ‘text/css'; 
case ‘js' : 
return ‘application/javascript'; 
case ‘json' : 
case ‘xml' : 
case ‘zip' : 
case ‘pdf' : 
case ‘rtf' : 
case ‘tar' : 
return ‘application/' . $fileSuffix; 
case ‘swf' : 
return ‘application/x-shockwave-flash'; 
case ‘flv' : 
return ‘video/x-flv'; 
case ‘jpe' : 
case ‘jpg' : 
return ‘image/jpeg'; 
case ‘jpeg' : 
case ‘png' : 
case ‘gif' : 
case ‘bmp' : 
case ‘tiff' : 
return ‘image/' . $fileSuffix; 
case ‘ico' : 
return ‘image/vnd.microsoft.icon'; 
case ‘tif' : 
return ‘image/tiff'; 
case ‘svg' : 
case ‘svgz' : 
return ‘image/svg+xml'; 
case ‘rar' : 
return ‘application/x-rar-compressed'; 
case ‘exe' : 
case ‘msi' : 
return ‘application/x-msdownload'; 
case ‘cab' : 
return ‘application/vnd.ms-cab-compressed'; 
case ‘aif' : 
return ‘audio/aiff'; 
case ‘mpg' : 
case ‘mpe' : 
case ‘mp3′ : 
return ‘audio/mpeg'; 
case ‘mpeg' : 
case ‘wav' : 
case ‘aiff' : 
return ‘audio/' . $fileSuffix; 
case ‘qt' : 
case ‘mov' : 
return ‘video/quicktime'; 
case ‘psd' : 
return ‘image/vnd.adobe.photoshop'; 
case ‘ai' : 
case ‘eps' : 
case ‘ps' : 
return ‘application/postscript'; 
case ‘doc' : 
case ‘docx' : 
return ‘application/msword'; 
case ‘xls' : 
case ‘xlt' : 
case ‘xlm' : 
case ‘xld' : 
case ‘xla' : 
case ‘xlc' : 
case ‘xlw' : 
case ‘xll' : 
return ‘application/vnd.ms-excel'; 
case ‘ppt' : 
case ‘pps' : 
return ‘application/vnd.ms-powerpoint'; 
case ‘odt' : 
return ‘application/vnd.oasis.opendocument.text'; 
case ‘ods' : 
return ‘application/vnd.oasis.opendocument.spreadsheet'; 
default : 
if (function_exists ( ‘mime_content_type' )) { 
$fileSuffix = mime_content_type ( $filename ); 
} else { 
$fileSuffix = ‘application/octet-stream'; 
} 
return $fileSuffix; 
break; 
} 
}