ceph/src/civetweb/src/third_party/duktape-1.3.0/examples/guide/prime.js

   1 // prime.js
   2
   3 // Pure Ecmascript version of low level helper
   4 function primeCheckEcmascript(val, limit) {
   5     for (var i = 2; i <= limit; i++) {
   6         if ((val % i) == 0) { return false; }
   7     }
   8     return true;
   9 }
  10
  11 // Select available helper at load time
  12 var primeCheckHelper = (this.primeCheckNative || primeCheckEcmascript);
  13
  14 // Check 'val' for primality
  15 function primeCheck(val) {
  16     if (val == 1 || val == 2) { return true; }
  17     var limit = Math.ceil(Math.sqrt(val));
  18     while (limit * limit < val) { limit += 1; }
  19     return primeCheckHelper(val, limit);
  20 }
  21
  22 // Find primes below one million ending in '9999'.
  23 function primeTest() {
  24     var res = [];
  25
  26     print('Have native helper: ' + (primeCheckHelper !== primeCheckEcmascript));
  27     for (var i = 1; i < 1000000; i++) {
  28         if (primeCheck(i) && (i % 10000) == 9999) { res.push(i); }
  29     }
  30     print(res.join(' '));
  31 }
  32