int SetBit(struct BitMap *psMap, int iIndex)
{
BITCHK_INDEX(psMap->_iSize, iIndex);
psMap->_szData[BIT_OFFSET(iIndex)] |= (0x01 << BIT_POS(iIndex));
return 0;
}
bool ht_acquire_slot(struct t_hash_table * ht, const uint8_t infohash[20], const uint32_t slot) {
/* may miss to lookup due to multithread issue, which would not affect functionality */
if (memcmp(ht->slot[slot].infohash, infohash, 20) == 0) {
return true;
}
while (1) {
uint8_t oldval = ht->used[BYTE_POS(slot)];
uint8_t newval = oldval | (1 << BIT_POS(slot));
if (oldval & (1 << BIT_POS(slot))) {
/* failed to acquire, already occupied */
return false;
}
/* try set used bit to 1 with CAS */
if (__sync_bool_compare_and_swap(&ht->used[BYTE_POS(slot)], oldval, newval)) {
memcpy(&ht->slot[slot].infohash, infohash, 20);
return true;
}
}
}
int main(int argc, const char * argv[])
{
int i, j = 15, k = 1;
i = (j++, k++);
#define SET_FLAG(N) (N) |= 1
#define BIT_POS(N) ( 1U << (N) )
// insert code here...
printf("k = %d\n", SET_FLAG(i));
printf("bit_ops = 0%X\n", BIT_POS(j));
printbinary(j);
return 0;
}
int GetBit(struct BitMap *psMap, int iIndex)
{
BITCHK_INDEX(psMap->_iSize, iIndex);
return (psMap->_szData[BIT_OFFSET(iIndex)] & (0x01 << BIT_POS(iIndex))) != 0;
}
void ps_slot_update(struct t_peer_storage * ps, uint32_t slot, uint8_t val) {
uint8_t mask = 0xFF - (0x0F << BIT_POS(slot));
mask |= (val << BIT_POS(slot));
__sync_fetch_and_and((uint8_t *)&ps->cycle_set[BYTE_POS(slot)], mask);
}
uint8_t ps_slot_read(struct t_peer_storage * ps, uint32_t slot) {
uint8_t mask = 0x0F << BIT_POS(slot);
uint8_t val = ps->cycle_set[BYTE_POS(slot)] & mask;
val >>= BIT_POS(slot);
return val;
}
uint8_t ps_slot_acquire(struct t_peer_storage * ps, uint32_t slot) {
uint8_t mask = 0x0F << BIT_POS(slot);
uint8_t val = __sync_fetch_and_or((uint8_t *)&ps->cycle_set[BYTE_POS(slot)], mask) & mask;
val >>= BIT_POS(slot);
return val;
}