/* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* HashKit library
*
* Copyright (C) 2011-2012 Data Differential, http://datadifferential.com/
* Copyright (C) 2006-2009 Brian Aker All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* * The names of its contributors may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <libhashkit/common.h>
#include <math.h>
#if 0
static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
{
unsigned char results[16];
md5_signature((unsigned char*)key, key_length, results);
return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
| ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
| ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
| (results[0 + alignment * 4] & 0xFF);
}
static int continuum_points_cmp(const void *t1, const void *t2)
{
hashkit_continuum_point_st *ct1= (hashkit_continuum_point_st *)t1;
hashkit_continuum_point_st *ct2= (hashkit_continuum_point_st *)t2;
if (ct1->value == ct2->value)
return 0;
else if (ct1->value > ct2->value)
return 1;
else
return -1;
}
int update_continuum(hashkit_st *hashkit)
{
uint32_t count;
uint32_t continuum_index= 0;
uint32_t value;
uint32_t points_index;
uint32_t points_count= 0;
uint32_t points_per_server;
uint32_t points_per_hash;
uint64_t total_weight= 0;
uint32_t live_servers;
uint8_t *context;
if (hashkit->active_fn != NULL || hashkit->weight_fn != NULL)
{
live_servers= 0;
for (count= 0, context= hashkit->list; count < hashkit->list_size;
count++, context+= hashkit->context_size)
{
if (hashkit->active_fn != NULL)
{
if (hashkit->active_fn(context))
live_servers++;
else
continue;
}
if (hashkit->weight_fn != NULL)
total_weight+= hashkit->weight_fn(context);
}
}
if (hashkit->active_fn == NULL)
live_servers= (uint32_t)hashkit->list_size;
if (live_servers == 0)
return 0;
if (hashkit->weight_fn == NULL)
{
points_per_server= HASHKIT_POINTS_PER_NODE;
points_per_hash= 1;
}
else
{
points_per_server= HASHKIT_POINTS_PER_NODE_WEIGHTED;
points_per_hash= 4;
}
if (live_servers > hashkit->continuum_count)
{
hashkit_continuum_point_st *new_continuum;
new_continuum= realloc(hashkit->continuum,
sizeof(hashkit_continuum_point_st) *
(live_servers + HASHKIT_CONTINUUM_ADDITION) *
points_per_server);
if (new_continuum == NULL)
return ENOMEM;
hashkit->continuum= new_continuum;
hashkit->continuum_count= live_servers + HASHKIT_CONTINUUM_ADDITION;
}
for (count= 0, context= hashkit->list; count < hashkit->list_size;
count++, context+= hashkit->context_size)
{
if (hashkit->active_fn != NULL && hashkit->active_fn(context) == false)
continue;
if (hashkit->weight_fn != NULL)
{
float pct = (float)hashkit->weight_fn(context) / (float)total_weight;
points_per_server= (uint32_t) ((floorf((float) (pct * HASHKIT_POINTS_PER_NODE_WEIGHTED / 4 * (float)live_servers + 0.0000000001))) * 4);
}
for (points_index= 0;
points_index < points_per_server / points_per_hash;
points_index++)
{
char sort_host[HASHKIT_CONTINUUM_KEY_SIZE]= "";
size_t sort_host_length;
if (hashkit->continuum_key_fn == NULL)
{
sort_host_length= (size_t) snprintf(sort_host, HASHKIT_CONTINUUM_KEY_SIZE, "%u",
points_index);
}
else
{
sort_host_length= hashkit->continuum_key_fn(sort_host, HASHKIT_CONTINUUM_KEY_SIZE,
points_index, context);
}
if (hashkit->weight_fn == NULL)
{
if (hashkit->continuum_hash_fn == NULL)
value= hashkit_default(sort_host, sort_host_length);
else
value= hashkit->continuum_hash_fn(sort_host, sort_host_length);
hashkit->continuum[continuum_index].index= count;
hashkit->continuum[continuum_index++].value= value;
}
else
{
unsigned int i;
for (i = 0; i < points_per_hash; i++)
{
value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
hashkit->continuum[continuum_index].index= count;
hashkit->continuum[continuum_index++].value= value;
}
}
}
points_count+= points_per_server;
}
hashkit->continuum_points_count= points_count;
qsort(hashkit->continuum, hashkit->continuum_points_count, sizeof(hashkit_continuum_point_st),
continuum_points_cmp);
return 0;
}
#endif