joaat

joaat.c

// joaat.c

#include <stdio.h>

unsigned long joaat_i(const unsigned char* s) {
  unsigned long hash = 0;
  while (*s) {
    hash += ((*s>64&&*s<91)?((*s++)+32):*s++); // A-Z -> a-z
    hash += (hash << 10);
    hash ^= (hash >> 6);
  }
  hash += (hash << 3);
  hash ^= (hash >> 11);
  hash += (hash << 15);
  return hash;
}

unsigned long joaat(const unsigned char* s) {
  unsigned long hash = 0;
  while (*s) {
    hash += *s++;
    hash += (hash << 10);
    hash ^= (hash >> 6);
  }
  hash += (hash << 3);
  hash ^= (hash >> 11);
  hash += (hash << 15);
  return hash;
}

int main(int argc, char* argv[])
{
	printf("%u %u %u %u\n", joaat(""), joaat("hello"), joaat("Hello"), joaat_i("Hello"));
	return 0;
}

joaat.lua

-- joaat.lua

function joaat(s)
  assert(type(s) == "string", "bad argument #1 to 'joaat' (string expected, got "..type(s)..")")
  local h = 0
  s = s:lower()
  for i = 1, s:len() do
    h = h + s:byte(i)
    h = h + (h << 10)
    h = h ~((h & 0xFFFFFFFF) >> 6)
  end
  h = h + (h << 3)
  h = h ~ ((h & 0xFFFFFFFF) >> 11)
  h = h + (h << 15)
  return h & 0xFFFFFFFF
end