Category talk:Wren-srandom

Source code

<lang ecmascript>/* Module "srandom.wren" */

import "io" for File

/*

   SRandom generates secure random integers from the /dev/urandom special file
   present on Linux or other Unix-like operating systems.

• /

class SRandom {

   // Returns an unsigned 32 bit integer between 0 and 4,294,967,295 inclusive.
   static int() {
       var n
       File.open("/dev/urandom") { |file|
           var b = file.readBytes(4).bytes.toList
           n = b[0] | b[1] << 8 | b[2] << 16 | b[3] << 24
       }
       return n
   }

   // Returns an integer between start and end, including start but excluding end.
   static int(start, end) {
       if (!(start is Num && start.isInteger && start >= 0 && start < 4294967296)) {
           Fiber.abort("Start must be a non-negative 32 bit integer.")
       }
       if (!(end is Num && end.isInteger && end > 0 && end < 4294967296)) {
           Fiber.abort("End must be a positive 32 bit integer.")
       }
       if (start >= end) Fiber.abort("Start must be less than end.")
       return start + int() % (end - start)
   }

   // Returns an integer between 0 and end, including 0 but excluding end.
   static int(end) { int(0, end) }

}</lang>