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
  
   #ok{color:green;}
   #nono{color:red;}
  

  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 '
';
    }
    }
   }
   ?>
   
   Again
   
  
   
   Filename:
   
   
   Expected hash(optional):
   
Choose an algorithm (This is the list of all the available algorithms in your php installation)
   $algo
";
    } else {
    echo "$algo
";
    }
   }
   ?>
  


希望本文所述对大家的php程序设计有所帮助。
            
            
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