src/storage/Util.cxx

   1 #include<Util.h>
   2 #include<Config.h>
   3
   4 unsigned int Util::hashBinary(char *strVal, int length)
   5 {
   6     unsigned int hval, g;
   7     hval = 0;
   8     char *str =strVal;
   9     int iter = 0;
  10     while (iter != length)
  11     {
  12         hval <<= 4;
  13         hval += (unsigned int) *str++;
  14         g = hval & ((unsigned int) 0xf << (32 - 4));
  15         if (g != 0)
  16             {
  17                 hval ^= g >> (32 - 8);
  18                 hval ^= g;
  19             }
  20         iter++;
  21     }
  22     return hval;
  23 }
  24
  25 DbRetVal GlobalUniqueID::create()
  26 {
  27     int key = Conf::config.getShmIDKey();
  28     int id = os::shm_create(key, MAX_UNIQUE_ID *sizeof(int), 0666);
  29     if (-1 == id) {
  30             printError(ErrOS, "Unable to create shared memory");
  31             return ErrOS;
  32     }
  33     ptr = os::shm_attach(id, NULL, 0);
  34     if ((void*)-1 == ptr) {
  35         printError(ErrOS, "Unable to attach shared memory");
  36             return ErrOS;
  37     }
  38     memset(ptr, 0, MAX_UNIQUE_ID *sizeof(int));
  39 }
  40
  41 DbRetVal GlobalUniqueID::open()
  42 {
  43     if (ptr != NULL) return OK;
  44     int key = Conf::config.getShmIDKey();
  45     int id = os::shm_open(key, MAX_UNIQUE_ID *sizeof(int), 0666);
  46     if (-1 == id) {
  47         printError(ErrOS, "Unable to create shared memory");
  48     }
  49     ptr = os::shm_attach(id, NULL, 0);
  50     if ((void*)-1 == ptr) {
  51         printError(ErrOS, "Unable to create shared memory");
  52     }
  53     return OK;
  54 }
  55
  56 DbRetVal GlobalUniqueID::destroy()
  57 {
  58     int key = Conf::config.getShmIDKey();
  59     int id = os::shm_open(key, MAX_UNIQUE_ID *sizeof(int), 0666);
  60     if (-1 == id) {
  61         printError(ErrOS, "Unable to open shared memory");
  62         return ErrOS;
  63     }
  64     os::shmctl(id, IPC_RMID);
  65 }
  66
  67 int GlobalUniqueID::getID(UniqueIDType type)
  68 {
  69     int *id = (int*)(((char*)ptr) + sizeof(int) * type);
  70     int oldVal = *id;
  71     int newVal = oldVal + 1;
  72     int ret = Mutex::CAS(id, oldVal, newVal);
  73     if (ret) return -1;
  74     return *id;
  75 }
  76