I see some real genious in this solution. This would be a great function addition to PHP, anybody?
Warren Vail Tools, Metrics & Quality Processes (415) 667-7814 Pager (877) 774-9891 215 Fremont 02-658 -----Original Message----- From: Rasmus Lerdorf [mailto:[EMAIL PROTECTED]] Sent: Wednesday, May 22, 2002 11:19 AM To: 1LT John W. Holmes Cc: Jason Soza; PHP-General Subject: Re: [PHP] voting using text files I think you guys are making this way more complicated than it needs to be. Anytime you start talking about locking files, you need to apply a huge reality check to yourself and sit down and approach the problem from a different direction. In this case could I suggest that you make use of the fact that appends of less than a blocksize are atomic. Therefore, why not simply append a single character to a text file for each vote? If you are voting for a list of things, assigning a character to each item and simply append 'a', 'b', 'c' or 'd' to your file. The size of the file instantly gives you the number of votes cast. Reading the file and counting the number of times each letter occurs using something like substr_count() will give you the number of votes for each option. That gives you a lockless and flexible system without the risk of deadlock or missing votes due to race conditions. -Rasmus On Wed, 22 May 2002, 1LT John W. Holmes wrote: > > A good structure would be to have one file for each possible answer and > each > > file contains the number of votes it has recieved. > > Then: > > --> Open file for the chosen option as read only > > --> Read the value in the file > > --> Close the file > > --> Increase the value by one using ++ > > --> Open the file again in write mode > > --> Lock the file > > --> Write the new value to the file - old one overwritten > > --> Unlock the file > > --> Close the file > > > That's a bad method. You have to have the lock around the read and the > write. With your method, 5 users might read the file, all getting 99 for the > count, and then each one will try to seperatly write 100 to the file. So you > lose 4 actual counts. You want to open the file, read it, update value, > write it, unlock, and close the file. > > Using multiple files would just be a waste of space in my opinion. A locked > file doesn't stop the script, it simply waits for the file to be unlocked > and then continues on. > > ---John Holmes... > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
