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         if (errno != EEXIST)
  31                 printError(ErrOS, "Unable to create shared memory");
  32             return ErrOS;
  33     }
  34     ptr = os::shm_attach(id, NULL, 0);
  35     if ((void*)-1 == ptr) {
  36         printError(ErrOS, "Unable to attach shared memory");
  37             return ErrOS;
  38     }
  39     memset(ptr, 0, MAX_UNIQUE_ID *sizeof(int));
  40 }
  41
  42 DbRetVal GlobalUniqueID::open()
  43 {
  44     if (ptr != NULL) return OK;
  45     int key = Conf::config.getShmIDKey();
  46     int id = os::shm_open(key, MAX_UNIQUE_ID *sizeof(int), 0666);
  47     if (-1 == id) {
  48         printError(ErrOS, "Unable to create shared memory");
  49     }
  50     ptr = os::shm_attach(id, NULL, 0);
  51     if ((void*)-1 == ptr) {
  52         printError(ErrOS, "Unable to create shared memory");
  53     }
  54     return OK;
  55 }
  56
  57 DbRetVal GlobalUniqueID::destroy()
  58 {
  59     int key = Conf::config.getShmIDKey();
  60     int id = os::shm_open(key, MAX_UNIQUE_ID *sizeof(int), 0666);
  61     if (-1 == id) {
  62 //        printError(ErrOS, "Unable to open shared memory");
  63         return ErrOS;
  64     }
  65     os::shmctl(id, IPC_RMID);
  66 }
  67
  68 int GlobalUniqueID::getID(UniqueIDType type)
  69 {
  70     int *id = (int*)(((char*)ptr) + sizeof(int) * type);
  71     int oldVal = *id;
  72     int newVal = oldVal + 1;
  73     int ret = Mutex::CAS(id, oldVal, newVal);
  74     if (ret) return -1;
  75     return *id;
  76 }
  77