Adding the ISAAC Random generator.

1 files changed, 160 insertions, 0 deletions

diff --git a/lib/RandISAAC.cc b/lib/RandISAAC.cc
new file mode 100644
index 0000000..2b0b09b
--- /dev/null
+++ b/lib/RandISAAC.cc
@@ -0,0 +1,160 @@
+/*
+ *  Baltisot
+ *  Copyright (C) 1999-2008 Nicolas "Pixel" Noble
+ *
+ *  This program 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 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/* $Id: RandISAAC.cc,v 1.1 2008-07-18 14:01:49 pixel Exp $ */
+
+/* Based on ISAAC. See original (C) mention below. */
+
+/*
+------------------------------------------------------------------------------
+rand.c: By Bob Jenkins.  My random number generator, ISAAC.  Public Domain
+MODIFIED:
+  960327: Creation (addition of randinit, really)
+  970719: use context, not global variables, for internal state
+  980324: make a portable version
+  010626: Note this is public domain
+------------------------------------------------------------------------------
+*/
+
+#include <stdio.h>
+
+#include <RandISAAC.h>
+
+#define bis(target,mask)  ((target) |=  (mask))
+#define bic(target,mask)  ((target) &= ~(mask))
+#define bit(target,mask)  ((target) &   (mask))
+
+#ifndef align
+# define align(a) (((Uint32)a+(sizeof(void *)-1))&(~(sizeof(void *)-1)))
+#endif /* align */
+
+#define ind(mm,x)  ((mm)[(x>>2)&(RANDSIZ-1)])
+#define rngstep(mix,a,b,mm,m,m2,r,x) \
+{ \
+  x = *m;  \
+  a = ((a^(mix)) + *(m2++)) & 0xffffffff; \
+  *(m++) = y = (ind(mm,x) + a + b) & 0xffffffff; \
+  *(r++) = b = (ind(mm,y>>RANDSIZL) + x) & 0xffffffff; \
+}
+
+void Random::isaac() {
+   Uint32 a,b,x,y,*m,*mm,*m2,*r,*mend;
+   mm=randmem; r=randrsl;
+   a = randa; b = (randb + (++randc)) & 0xffffffff;
+   for (m = mm, mend = m2 = m+(RANDSIZ/2); m<mend; )
+   {
+      rngstep( a<<13, a, b, mm, m, m2, r, x);
+      rngstep( a>>6 , a, b, mm, m, m2, r, x);
+      rngstep( a<<2 , a, b, mm, m, m2, r, x);
+      rngstep( a>>16, a, b, mm, m, m2, r, x);
+   }
+   for (m2 = mm; m2<mend; )
+   {
+      rngstep( a<<13, a, b, mm, m, m2, r, x);
+      rngstep( a>>6 , a, b, mm, m, m2, r, x);
+      rngstep( a<<2 , a, b, mm, m, m2, r, x);
+      rngstep( a>>16, a, b, mm, m, m2, r, x);
+   }
+   randb = b; randa = a;
+}
+
+
+#define mix(a,b,c,d,e,f,g,h) \
+{ \
+   a^=b<<11; d+=a; b+=c; \
+   b^=c>>2;  e+=b; c+=d; \
+   c^=d<<8;  f+=c; d+=e; \
+   d^=e>>16; g+=d; e+=f; \
+   e^=f<<10; h+=e; f+=g; \
+   f^=g>>4;  a+=f; g+=h; \
+   g^=h<<8;  b+=g; h+=a; \
+   h^=a>>9;  c+=h; a+=b; \
+}
+
+/* if (flag==TRUE), then use the contents of randrsl[] to initialize mm[]. */
+void Random::randinit(int flag) {
+   int i;
+   Uint32 a,b,c,d,e,f,g,h;
+   Uint32 *m,*r;
+   randa = randb = randc = 0;
+   m=randmem;
+   r=randrsl;
+   a=b=c=d=e=f=g=h=0x9e3779b9;  /* the golden ratio */
+
+   for (i=0; i<4; ++i)          /* scramble it */
+   {
+     mix(a,b,c,d,e,f,g,h);
+   }
+
+   if (flag) 
+   {
+     /* initialize using the contents of r[] as the seed */
+     for (i=0; i<RANDSIZ; i+=8)
+     {
+       a+=r[i  ]; b+=r[i+1]; c+=r[i+2]; d+=r[i+3];
+       e+=r[i+4]; f+=r[i+5]; g+=r[i+6]; h+=r[i+7];
+       mix(a,b,c,d,e,f,g,h);
+       m[i  ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
+       m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
+     }
+     /* do a second pass to make all of the seed affect all of m */
+     for (i=0; i<RANDSIZ; i+=8)
+     {
+       a+=m[i  ]; b+=m[i+1]; c+=m[i+2]; d+=m[i+3];
+       e+=m[i+4]; f+=m[i+5]; g+=m[i+6]; h+=m[i+7];
+       mix(a,b,c,d,e,f,g,h);
+       m[i  ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
+       m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
+     }
+   }
+   else
+   {
+     for (i=0; i<RANDSIZ; i+=8)
+     {
+       /* fill in mm[] with messy stuff */
+       mix(a,b,c,d,e,f,g,h);
+       m[i  ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
+       m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
+     }
+   }
+
+   isaac();            /* fill in the first set of results */
+   randcnt=RANDSIZ;  /* prepare to use the first set of results */
+}
+
+Random::Random() {
+    int i;
+    
+    srand(time(NULL));
+    for (i = 0; i < RANDSIZ; i++) {
+        randrsl[i] = rand();
+    }
+    randinit(1);
+}
+
+Random::~Random() {
+}
+
+Uint32 Random::get() {
+    if (!randcnt--) {
+        isaac();
+        randcnt = RANDSIZ - 1;
+    }
+    return randrsl[randcnt];
+}