//this is per ds
#define BW_HASH_SIZE 0x4000
#define BW_HASH_MASK (BW_HASH_SIZE-1)
#define BW_HASH(ptr) ((unsigned)ptr>>4)&BW_HASH_MASK
#define BW_HASH(ptr) ((unsigned long)ptr>>4)&BW_HASH_MASK
class BWEngine {
public: