HashTables verständnisprobleme

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:

nodePool( int maxNodes , int hashSize ) :
	m_nodes( 0 ) ,
	m_first( 0 ) ,
	m_next( 0 ) ,
	m_maxNodes( maxNodes ) ,
	m_hashSize( hashSize ) ,
	m_nodeCount( 0 )
{
	m_nodes = (dtNode*)alloc( sizeof( node )*m_maxNodes , ALLOC_PERM );
	m_next = (nodeIndex*)alloc( sizeof( nodeIndex ) * m_maxNodes , ALLOC_PERM );
	m_first = (nodeIndex*)alloc( sizeof( nodeIndex ) * hashSize , ALLOC_PERM );
  
	memset( m_first , 0xff , sizeof( nodeIndex ) * m_hashSize );
	memset( m_next , 0xff , sizeof( nodeIndex ) * m_maxNodes );
}

unsigned int hashRef( a )
{
	a += ~( a << 15 );
	a ^= ( a >> 10 );
	a += ( a << 3 );
	a ^= ( a >> 6 );
	a += ~( a << 11 );
	a ^= ( a >> 16 );

	return (unsigned int)a;
}

findNode( id )
{
	unsigned int bucket = hashRef( id ) & ( m_hashSize - 1 );

	int i = m_first[bucket];

	while( i != NULL )
	{
		if( m_nodes[i].id == id )
			return &m_nodes[i];

		i = m_next[i];
	}

	return 0;
}