php对文件进行hash运算的方法
本文实例讲述了php对文件进行hash运算的方法。分享给大家供大家参考。具体如下：
这段代码非常有用，如果你下载了一个文件，网站提供了hash结果，你可以对你下载下来的文件进行hash运算，以验证下载的文件是否正确。
Hash (Check) Files
0){
switch($_FILES["file"]["error"]){
case 1:
echo "Error: The uploaded file exceeds the upload_max_filesize directive in php.ini
";
break;
case 2:
echo "Error: The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.
";
break;
case 3:
echo "Error: The uploaded file was only partially uploaded.
";
break;
case 4:
echo "Error: No file was uploaded.
";
break;
case 6:
echo "Error: Missing a temporary folder.
";
break;
case 7:
echo "Error: Failed to write file to disk.
";
break;
case 8:
echo "Error: A PHP extension stopped the file upload.
";
break;
default:
echo "Unknown error occured.
";
}
} else {
echo 'Upload: ' . $_FILES['file']['name'] . '
';
echo 'Type: ' . $_FILES['file']['type'] . '
';
echo 'Size: ' . (round($_FILES['file']['size'] / 1024, 2)) . ' Kb
';
if(array_search($_POST['algo'], hash_algos())===false){
echo 'Unknown hashing algorithm requested.
';
} else {
echo 'Hashing Algorithm: '. $_POST['algo'] . '
';
$hash = hash_file($_POST['algo'], $_FILES['file']['tmp_name']);
echo 'Calculated hash: ' . $hash . '
';
if($_POST['exphash']!=='none' && !empty($_POST['exphash'])){
echo 'Expected hash: ' . $_POST['exphash'] . '
';
echo ($hash==$_POST['exphash'])? 'Hash matched expected value.' : 'Hash did not match expected value.';
echo '
';
}
}
}
?>
希望本文所述对大家的php程序设计有所帮助。