datastructures.txt

There are four major datastructures in lightweight that needs a bit of
explanation:

Main user database
- This datastructure holds all the currently active users on the network.
  It is organised by first a servernumeric order and then a usernumeric.
  Alternatively the entries in this structure can be accessed through a
  hashed list of linked lists of nicks.
  So the two entries to these records are:
  1. An array of length 4096 representing each server, each entry is a pointer
  to a dynamically allocated array of length equal to the corresponding
  servers maxusers. Each entry in these dynamically allocated arrays is a
  pointer to a dynamically allocated user struct.
  Doing it this way ensures a O(1) lookup of users from the usernumeric,
  and this is smart as commands often comes prefixed with the usernumeric
  as sender, and not the nick.
  2. An array of length HASHMAX where each entry points to the start of a
  linked list of user structs. The user structs are placed randomly in the
  linked list which is at the value that corresponds to the users nicks
  hashed value.

  entry: 1. usertablepointer and 2. nickhashtable.

Main account database
- This structure holds all the accounts known to lightweight. It is organised
  just like the second way the user database is organised.

  entry: accounthashtable.

Main channel database
- This structure holds all the channels known to lightweight (this is _not_
  the channels that currently exists on the network, we dont give a shit
  about those). It is organised just like the account database.

  entry: channelhashtable.

Servertree
- This structure holds information about the servertree to use when netsplits
  occur.
  When a server sends a SQUIT, run through the whole list of servers and
  act as if the servers with the quitting one as parent had sent a SQUIT
  (notice the recursion here). Then act as if all the servers users QUIT
  and finally remove the server from the servertree and free it.
  It is wellknown that this is very bad performancewise, but the number of
  servers is limited and it happends very seldom. Live with it...

  entry: servertree

Savefile (called accounts.0 pr. default)
- This is the way the static of the above structures gets saved to disk.
  The file begins with a list of the accounts known to L. Each line consist
  of (the linedata are between the quotes):

  "<accountname> <authlevel> <lastauth>"

  where accountname is a string of chars allowable in normal nicks,
  authlevel is an integer between 1 and 255 and lastauth is a unix timestamp.
  Following this is a single line:

  "--- End of users"

  After the users comes the channels. A channel is represented like this:
  First a single line with the static channeldata:

  "<channelname> <addedby-account> <founder-account> <lastused-timestamp>"

  And then multiple line (max. USERSPERCHANNEL) each on the form:

  "<accountname> <flags>"

  (flags is here a fixed width string of 8 chars, each representing
  a channelflag).
  After all accounts has been listed, a single line shows the end of the
  channel:

  "--- End of channel <channelname>"

  entry: there is no direct access to the files while the program run,
	 all access happens through restoredbfromdisk.c and savedbtodisk.c.