X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/07871354bfa8bbbacb6c6a1966f25b596119c146..283b9af095a5b24ae71b49a6d2dcbdcdaae47c40:/lcrand.c

diff --git a/lcrand.c b/lcrand.c
index 3686e17..f53a3f2 100644
--- a/lcrand.c
+++ b/lcrand.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: lcrand.c,v 1.1 1999/12/10 23:15:27 mdw Exp $
+ * $Id: lcrand.c,v 1.4 2000/12/06 20:31:06 mdw Exp $
  *
  * Simple linear congruential generator
  *
@@ -30,6 +30,15 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: lcrand.c,v $
+ * Revision 1.4  2000/12/06 20:31:06  mdw
+ * Simplify uniform range transformation.
+ *
+ * Revision 1.3  2000/06/17 11:29:03  mdw
+ * Add the flags word to the generic generator.
+ *
+ * Revision 1.2  1999/12/13 15:34:01  mdw
+ * Add support for seeding from a generic pseudorandom source.
+ *
  * Revision 1.1  1999/12/10 23:15:27  mdw
  * Noncryptographic random number generator.
  *
@@ -172,7 +181,7 @@ uint32 lcrand_range(uint32 *x, uint32 m)
   uint32 r = P - P % m;
   do xx = lcrand(xx); while (xx >= r);
   *x = xx;
-  return (xx / (r / m));
+  return (xx % m);
 }
 
 /*----- Generic interface -------------------------------------------------*/
@@ -201,6 +210,7 @@ static int gmisc(grand *r, unsigned op, ...)
 	case GRAND_CHECK:
 	case GRAND_SEEDINT:
 	case GRAND_SEEDUINT32:
+	case GRAND_SEEDRAND:
 	  rc = 1;
 	  break;
 	default:
@@ -214,6 +224,12 @@ static int gmisc(grand *r, unsigned op, ...)
     case GRAND_SEEDUINT32:
       g->x = va_arg(ap, uint32);
       break;
+    case GRAND_SEEDRAND: {
+      grand *rr = va_arg(ap, grand *);
+      uint32 x;
+      do x = rr->ops->word(rr); while (x >= P || x == LCRAND_FIXEDPT);
+      g->x = x;
+    } break;
     default:
       GRAND_BADOP;
       break;
@@ -247,7 +263,7 @@ static uint32 grange(grand *r, uint32 l)
 
 static const grand_ops gops = {
   "lcrand",
-  LCRAND_P,
+  LCRAND_P, 0,
   gmisc, gdestroy,
   graw, gbyte, grand_word, grange, grand_fill
 };