prng/seeder.d

   1 /* Invisible Vector Library
   2  * coded by Ketmar // Invisible Vector <ketmar@ketmar.no-ip.org>
   3  * Understanding is not required. Only obedience.
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 3 of the License ONLY.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 module iv.prng.seeder /*is aliced*/;
  18 import iv.alice;
  19
  20
  21 public uint xyzzyPRNGHashU32() (uint a) {
  22   a -= (a<<6);
  23   a ^= (a>>17);
  24   a -= (a<<9);
  25   a ^= (a<<4);
  26   a -= (a<<3);
  27   a ^= (a<<10);
  28   a ^= (a>>15);
  29   return a;
  30 }
  31
  32
  33 public uint getTwoUintSeeds (uint* second=null) nothrow @trusted @nogc {
  34   version(Windows) {
  35     import core.sys.windows.windef, core.sys.windows.winbase;
  36     uint s0 = xyzzyPRNGHashU32(cast(uint)GetCurrentProcessId());
  37     uint s1 = xyzzyPRNGHashU32(cast(uint)GetTickCount());
  38     if (second is null) return s0^s1;
  39     *second = s1;
  40     return s0;
  41   } else {
  42     // assume POSIX
  43     import core.sys.posix.fcntl;
  44     import core.sys.posix.unistd;
  45     uint s0 = 0xdeadf00du;
  46     int fd = open("/dev/urandom", O_RDONLY);
  47     if (fd >= 0) {
  48       // assume that we always have endless supply of bytes from that
  49       read(fd, &s0, s0.sizeof);
  50       if (second !is null) read(fd, second, (*second).sizeof);
  51       close(fd);
  52       return s0;
  53     }
  54     // try something another
  55     import core.sys.posix.unistd;
  56     import core.sys.posix.time;
  57     s0 = cast(uint)xyzzyPRNGHashU32(cast(uint)getpid());
  58     timespec stt = void;
  59     if (clock_gettime(CLOCK_MONOTONIC, &stt) == 0) {
  60       uint s1 = xyzzyPRNGHashU32(cast(uint)(stt.tv_sec^stt.tv_nsec));
  61       if (second is null) return s0^s1;
  62       *second = s1;
  63       return s0;
  64     }
  65     if (second is null) *second = xyzzyPRNGHashU32(s0);
  66     return s0;
  67   }
  68 }
  69
  70
  71 public ulong getUlongSeed () nothrow @trusted @nogc {
  72   uint s1;
  73   uint s0 = getTwoUintSeeds(&s1);
  74   return ((cast(ulong)s1)<<32)|s0;
  75 }