client & file table ds

[gilayalon]

Create a data structure to manage available clients & files.

[gilayalon]

Use a binary search tree for the file table (ordered by name).
Use a hash table for the client lists.

---

| filename | client list |

Each client is a struct with fields ip & port.

Operations:
(n = file count, m = client count)

1. DIR - The file list contains only files that are 'online', so just send the list to the client. O(n)
2. GET - Find the requested file in the list, randomly select a client for download. O(logn)
3. CONNECT - Loop through the client file list, marking each available file. If the file is 'online', add the client to the file's client list (can be done during the search); Else, insert the file at the end. O(m'logm)
4. DISCONNECT - Loop through the file list. For each file, search the client list for the disconnecting client. If it exists, delete it. If the client list is empty, delete the file. O(m)