flower/hash.cc

   1 #include "string.hh"
   2 #include "array.hh"
   3 #include "dictionary.hh"
   4
   5
   6 // Note: assumes long is at least 32 bits.
   7 const unsigned long my_prime_list[] =
   8 {
   9   53,         97,         193,       389,       769,
  10   1543,       3079,       6151,      12289,     24593,
  11   49157,      98317,      196613,    393241,    786433,
  12   1572869,    3145739,    6291469,   12582917,  25165843,
  13   50331653,   100663319,  201326611, 402653189u, 805306457u,
  14   1610612741u, 3221225473u, 4294967291u
  15 };
  16
  17 unsigned long prime_list (int idx)
  18 {
  19   return my_prime_list [idx];
  20 }
  21
  22 unsigned int hash (String s)
  23 {
  24   const char* str = s.ch_C ();
  25   unsigned int result = 0;
  26   while (1) {
  27     char c = *str++;
  28     if (c == 0) break;
  29       result += (result<<3) + c;
  30   }
  31   return result;
  32 }
  33