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。

rush:PHP;"> 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'])? '' : ''; echo '
'; } } } ?>

Expected hash(optional):

Choose an algorithm (This is the list of all the available algorithms in your PHP installation)
PHP foreach(hash_algos() as $algo){ if($algo=='md5'){ echo "$algo
"; } else { echo "$algo
"; } } ?>

希望本文所述对大家的PHP程序设计有所帮助。