int main(int argc, char **argv)
{
if(argc==1){
printf("Usage: %s <ketama.servers file>\n", *argv);
return 1;
}
ketama_continuum c;
serverinfo* serverinfo;
ketama_roll( &c, *++argv, serverinfo );
printf( "%s\n", ketama_error() );
int i;
for ( i = 0; i < 1000000; i++ )
{
char k[10];
sprintf( k, "%d", i );
unsigned int kh = ketama_hashi( k );
mcs* m = ketama_get_server( k, c );
printf( "%u %u %s\n", kh, m->point, m->ip );
}
ketama_smoke(c);
return 0;
}
mcs*
ketama_get_server( char* key, ketama_continuum cont )
{
unsigned int h = ketama_hashi( key );
int highp = cont->numpoints;
mcs (*mcsarr)[cont->numpoints] = cont->array;
int lowp = 0, midp;
unsigned int midval, midval1;
// divide and conquer array search to find server with next biggest
// point after what this key hashes to
while ( 1 )
{
midp = (int)( ( lowp+highp ) / 2 );
if ( midp == cont->numpoints )
return &( (*mcsarr)[0] ); // if at the end, roll back to zeroth
midval = (*mcsarr)[midp].point;
midval1 = midp == 0 ? 0 : (*mcsarr)[midp-1].point;
if ( h <= midval && h > midval1 )
return &( (*mcsarr)[midp] );
if ( midval < h )
lowp = midp + 1;
else
highp = midp - 1;
if ( lowp > highp )
return &( (*mcsarr)[0] );
}
}
static int
lketama_fnv1a32digest(lua_State *L){
const char *str = luaL_checkstring(L, 2);
int hval = ketama_hashi((char*)str);
lua_pushfstring(L, "%d", hval);
return 1;
}
static int
lketama_hashi(lua_State *L){
const char *str = luaL_checkstring(L, 2);
unsigned int res = ketama_hashi((char*)str);
lua_pushnumber(L, res);
return 1;
}
PY_DEF(pyketama_hashi, self, args) {
char *data;
PyObject *r = NULL;
if (PyArg_ParseTuple(args, "s", &data)) {
r = Py_BuildValue("I", ketama_hashi(data));
}
}
mcs*
ketama_get_server( char* key, ketama_continuum cont )
{
unsigned int h = ketama_hashi( key );
int lowp = 0, midp, highp;
unsigned int midval, midval1;
// verify that a valid resource was passed in before getting its key
if (cont == NULL) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_get_server passed illegal pointer to a continuum resource.\n" );
syslog1( LOG_INFO, k_error );
return NULL;
}
key_t fkey = cont->key;
// try to find an existsing resource with a shared memory segment in the array of tracked resources, or create a new attachment resource
if ( !get_shm_resource(fkey, cont) ) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_get_server failed to get a valid resource.\n" );
syslog1( LOG_INFO, k_error );
return NULL;
}
// divide and conquer array search to find server with next biggest
// point after what this key hashes to
highp = cont->data->numpoints;
while ( 1 ) {
midp = ( lowp+highp ) >> 1;
if ( midp == cont->data->numpoints )
return &cont->data->array[0]; // if at the end, roll back to zeroth
midval = cont->data->array[midp].point;
midval1 = midp == 0 ? 0 : cont->data->array[midp-1].point;
if ( h <= midval && h > midval1 )
return &cont->data->array[midp];
if ( midval < h )
lowp = ++midp;
else
highp = --midp;
if ( lowp > highp )
return &cont->data->array[0];
}
}
redisContext *lookupRedisServerWithKey( proxyContext *p, const char *key ) {
unsigned int h = ketama_hashi( key );
int highp = p->mcs_count-1;
int lowp = 0, midp;
unsigned int midval, midval1;
ketamaMCS *mcs = p->mcs;
while ( lowp < highp )
{
midp = (int)( ( lowp+highp ) / 2 );
midval = mcs[midp].point;
midval1 = (midp == 0) ? 0 : mcs[midp-1].point;
if ( h <= midval && h > midval1 )
return getFirstContext(p, midp);
if ( midval < h )
lowp = midp + 1;
else
highp = midp - 1;
}
return getFirstContext(p, lowp);
}
