/*
 *  NeoIRCd: NeoStats Group. Based on Hybird7
 *  scache.c: Server names cache.
 *
 *  Copyright (C) 2002 by the past and present ircd coders, and others.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id: scache.c,v 1.5 2002/10/31 13:01:58 fishwaldo Exp $
 */

#include "stdinc.h"
#include "client.h"
#include "common.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "send.h"
#include "scache.h"
#include "memory.h"


/*
 * ircd used to store full servernames in anUser as well as in the 
 * whowas info.  there can be some 40k such structures alive at any
 * given time, while the number of unique server names a server sees
 * in its lifetime is at most a few hundred.  by tokenizing server
 * names internally, the server can easily save 2 or 3 megs of RAM.  
 * -orabidoo
 */


#define SCACHE_HASH_SIZE 257

typedef struct scache_entry
{
  char name[HOSTLEN+1];
  struct scache_entry *next;
} SCACHE;

static SCACHE *scache_hash[SCACHE_HASH_SIZE];

void clear_scache_hash_table(void)
{
  memset(scache_hash, 0, sizeof(scache_hash));
}

static int hash(const char* string)
{
  int hash_value;

  hash_value = 0;
  while (*string)
    {
      hash_value += ToLower(*string);
      /* I don't like auto increments inside macro calls... -db */
      string++;
    }

  return hash_value % SCACHE_HASH_SIZE;
}

/*
 * this takes a server name, and returns a pointer to the same string
 * (up to case) in the server name token list, adding it to the list if
 * it's not there.  care must be taken not to call this with
 * user-supplied arguments that haven't been verified to be a valid,
 * existing, servername.  use the hash in list.c for those.  -orabidoo
 */

const char* find_or_add(const char* name)
{
  int     hash_index;
  SCACHE* ptr;

  ptr = scache_hash[hash_index = hash(name)];
  for ( ; ptr; ptr = ptr->next) 
    {
      if (!irccmp(ptr->name, name))
        return(ptr->name);
    }

  ptr = (SCACHE*) MyMalloc(sizeof(SCACHE));
  assert(0 != ptr);

  strlcpy(ptr->name, name, sizeof(ptr->name));

  ptr->next = scache_hash[hash_index];
  scache_hash[hash_index] = ptr;
  return ptr->name;  
}

/*
 * count_scache
 * inputs	- pointer to where to leave number of servers cached
 *		- pointer to where to leave total memory usage
 * output	- NONE
 * side effects	-
 */
void count_scache(int *number_servers_cached,u_long *mem_servers_cached)
{
  SCACHE *scache_ptr;
  int i;

  *number_servers_cached = 0;
  *mem_servers_cached = 0;

  for(i = 0; i < SCACHE_HASH_SIZE ;i++)
    {
      scache_ptr = scache_hash[i];
      while(scache_ptr)
        {
          *number_servers_cached = *number_servers_cached + 1;
          *mem_servers_cached = *mem_servers_cached +
            (strlen(scache_ptr->name) +
             sizeof(SCACHE *));

          scache_ptr = scache_ptr->next;
        }
    }
}