X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Frkiss.h;h=0863c9cf7520ce279c4f1666f97e17d4ae52f290;hp=6e94dc27fa723fc8426216df2fbf0bf3cf2e452c;hb=c980163316d48ff304bfb253089c7d474d090b12;hpb=f5e28ef5127ff29310f9c2e8e321eb24214f2439

diff --git a/src/rkiss.h b/src/rkiss.h
index 6e94dc27..0863c9cf 100644
--- a/src/rkiss.h
+++ b/src/rkiss.h
@@ -1,4 +1,26 @@
-/** *********************************************************************** **
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+  This file is based on original code by Heinz van Saanen and is
+  available under the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
  ** A small "keep it simple and stupid" RNG with some fancy merits:
  **
  ** Quite platform independent
@@ -8,70 +30,49 @@
  ** Average cycle length: ~2^126
  ** 64 bit seed
  ** Return doubles with a full 53 bit mantissa
- ** Thread save
+ ** Thread safe
  **
  ** (c) Heinz van Saanen
 
-  This file is free software: you can redistribute it and/or modify
-  it under the terms of the GNU General Public License as published by
-  the Free Software Foundation, either version 3 of the License, or
-  (at your option) any later version.
+*/
 
-  This file is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  GNU General Public License for more details.
+#if !defined(RKISS_H_INCLUDED)
+#define RKISS_H_INCLUDED
 
-  You should have received a copy of the GNU General Public License
-  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#include "types.h"
 
- ** *********************************************************************** **/
+class RKISS {
 
-#ifndef _RKISS_H_
-#define _RKISS_H_
+  // Keep variables always together
+  struct S { uint64_t a, b, c, d; } s;
 
-/** Includes **/
-#include <cstdlib>    // srand(), rand()
-#include <ctime>      // time()
-#include "types.h"    // (u)int8_t .. (u)int64_t
+  uint64_t rot(uint64_t x, uint64_t k) const {
+    return (x << k) | (x >> (64 - k));
+  }
 
+  // Return 64 bit unsigned integer in between [0, 2^64 - 1]
+  uint64_t rand64() {
 
-/** Random class **/
-class RKISS {
+    const uint64_t
+      e = s.a - rot(s.b,  7);
+    s.a = s.b ^ rot(s.c, 13);
+    s.b = s.c + rot(s.d, 37);
+    s.c = s.d + e;
+    return s.d = e + s.a;
+  }
 
-private:
-	// Keep variables always together
-	struct S { uint64_t a; uint64_t b; uint64_t c; uint64_t d; } s;
+  // Init seed and scramble a few rounds
+  void raninit() {
 
-	// Init seed and scramble a few rounds
-	void raninit ( uint64_t seed ) {
-		s.a = 0xf1ea5eed; s.b = s.c = s.d = seed;
-		for ( uint64_t i=0; i<8; i++ ) rand64();
-	}
+    s.a = 0xf1ea5eed;
+    s.b = s.c = s.d = 0xd4e12c77;
+    for (int i = 0; i < 73; i++)
+        rand64();
+  }
 
 public:
-	// Instance seed random or implicite
-	RKISS() { ::srand ( (uint32_t)time(NULL) ); raninit ( (uint64_t)::rand() ); }
-	// RKISS( uint64_t s ) { raninit ( s ); }
-
-	// (Re)init seed
-	// void init ( uint64_t seed ) { raninit ( seed ); }
-
-	// Return 32 bit unsigned integer in between [0,2^32-1]
-	uint32_t rand32 () { return (uint32_t) rand64 (); }
-
-	// Return 64 bit unsigned integer in between [0,2^64-1]
-	uint64_t rand64 () {
-		const uint64_t e = s.a - ((s.b<<7) | (s.b>>57));
-		s.a = s.b ^ ((s.c<<13) | (s.c>>51));
-		s.b = s.c + ((s.d<<37) | (s.d>>27));
-		s.c = s.d + e;
-		return s.d = e + s.a;
-	}
-
-	// Return double in between [0,1). Keep full 53 bit mantissa
-	// double frand () { return (int64_t)(rand64()>>11) * (1.0/(67108864.0*134217728.0)); }
+  RKISS() { raninit(); }
+  template<typename T> T rand() { return T(rand64()); }
 };
 
-// _RKISS_H_
-#endif
+#endif // !defined(RKISS_H_INCLUDED)