javascript - Converting JS Using Google.Math.Long to C# -


i converting javascript code c# , having bit of trouble google math longs , how function. version of delphi random function - according co dev.

in javascript have this.

function _nextrandom(maxvalue, seedvalue) {     if (seedvalue !== null)          _seed = new goog.math.long(seedvalue);      _seed = _seed.multiply(134775813).add(_one);     _seed = new goog.math.long(_seed.getlowbitsunsigned());     return _seed.multiply(new goog.math.long(maxvalue)).gethighbits() >>> 0; }

in c# have - far.

private int _nextrandom(int maxvalue, int seedvalue) {     if (seedvalue != 0)         _seed = seedvalue;      _seed = _seed * 134775813 + 1;     _seed = (long)((int)_seed); // lower 32 bits     return (int)(((ulong)_seed * (ulong)maxvalue) >> 32); // upper 32 bits }

max value 254 , first time _nextrandom run seedvalue 1024 every other time afterwards 0 (in c#) or null (in js)

here output c# correct positive values, negative ones incorrect

casting values byte makes values match not exactly.

does have ideas why happening?

a couple of problems:

  • you have declared _seed 64 bit long. should 32 bit int.
  • you need cast _seed , maxvalue uint before performing 64 bit multiplication.

the following c# code replicates delphi prng:

private static int _seed = 0;  private static int _nextrandom(int maxvalue, int seedvalue) {     if (seedvalue != 0)         _seed = seedvalue;     _seed = _seed * 0x08088405 + 1;     return (int)(((ulong)(uint)_seed * (uint)maxvalue) >> 32); }

obviously code not threadsafe sure know that. cleaner implementation wrap in class create distinct instances of prng own seed.


Comments

Post a Comment

Popular posts from this blog

javascript - jQuery: Add class depending on URL in the best way -

i have html progress meter: <div class="col-md-3" style="margin-left: -20px;"> <div class="progress-pos active" id="progess-1"> <div class="progress-pos-inner"> login </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-2"> <div class="progress-pos-inner"> scan items </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-3"> <div class="progress-pos-inner"> confirm address </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-4"> <div class="progress-pos-in...
Read more

caching - How to check if a url path exists in the service worker cache -

i need check if particular url path exists in service worker cache. example, suppose url is: /myserviceworker/service?a=110&b=70 this url exists in cache, there many of them different values of , b. now, suppose want refresh of these urls, how can that? i want know how access key values service worker cache. if know key, plan follows: var url = new url(key); if(url.pathname === "\/myserviceworker/service") refetch key but not sure how cache key , in format is. mean, string or url? cache api has match() method returns promise resolving in response object if match or undefined if no match exists. second parameter object can specify ignoresearch not take account url parameters. the ignoresearch option supported firefox ( chrome status here ). in other hand, retrieve cache entries, can use keys() method.
Read more

Redirect to a HTTPS version using .htaccess -

i need modify .htaccess file redirect urls https version without "www". http://example.com --> https://example.com http://www.example.com --> https://example.com https://www.example.com --> https://example.com this how .htaccess file looks like: rewriteengine on rewritecond %{request_filename} !-d rewritecond %{request_filename} !-f rewriterule ^(.*)$ redirect.php?id=$1&page=$2 [qsa,l] what modifications need make .htaccess in order forward https without "www"? it depends on doing current code. looks file called redirect trying display php page seo friendly url. think might confusing people. anyway, need , force https without www, need 1 more rule above. also second rule needs two capture groups in rewriterule test string because wanting 2 different values using $1 , $2 references. rewriteengine on #rediect www non www and/or http https --- combinations. rewritecond %{http_host} !^example\.com [nc,or] rewritecond %{https} !^...
Read more