LSL NSieve Bits Benchmark

<lsl> // // The Great Computer Language Shootout // http://shootout.alioth.debian.org/ // // contributed by Isaac Gouy // modified by Babbage Linden //

string hexc="0123456789ABCDEF";

string setBitArray(integer numbits) {

   string result = "";
   integer i;
   for(i = 0; i < numbits; i += 4)
   {
       result += "F";
   }
   result += "F";
   return result;

}

string replace(string s, integer index, string char) {

   string result = "";
   if(index >= 1)
   { 
       result += llGetSubString(s, 0, index - 1);
   }
   result += char;
   if(index < (llStringLength(s) - 1))
   {
       result += llGetSubString(s, index + 1, -1);
   }
   return result;

}

integer get(string s, integer index) {

   integer charIndex = index / 4;
   integer bitIndex = index % 4;
   integer bits = (integer)("0x" + llGetSubString(s, charIndex, charIndex));
   return (bits & (1 << bitIndex));

}

string set(string s, integer index) {

   integer charIndex = index / 4;
   integer bitIndex = index % 4;
   integer bits = (integer)("0x" + llGetSubString(s, charIndex, charIndex));
   bits = bits | (1 << bitIndex);
   return replace(s, charIndex, llGetSubString(hexc, bits, bits));

}

string unset(string s, integer index) {

   integer charIndex = index / 4;
   integer bitIndex = index % 4;
   integer bits = (integer)("0x" + llGetSubString(s, charIndex, charIndex));
   integer mask = 0xF & ~(1 << bitIndex);
   bits = bits & mask;
   return replace(s, charIndex, llGetSubString(hexc, bits, bits));

}

test() {

   integer m = 128;
   string bits = setBitArray(m);
   integer count = 0;

   integer i;
   for (i=2; i <= m; i++)
   {
        if(get(bits, i))
        {
           integer k;
           for(k=i+i; k <= m; k+=i)
           {
               bits = unset(bits, k);
           }
           count++;
        }
   }
   llSay(0, "Primes up to " + (string)m + " " + (string)count);

}

time() {

   llResetTime();
   llSay(0, "Starting tests...");
   test();
   llSay(0, "Finished tests in " + (string)llGetTime() + "s");

}

default {

   state_entry()
   {
       time();
   }
   
   touch_start(integer num)
   {
       time();
   }

} </lsl>