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diff --git a/src/isaac_rand/isaac_rand.h b/src/isaac_rand/isaac_rand.h
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+/*
+------------------------------------------------------------------------------
+rand.h: definitions for a random number generator
+By Bob Jenkins, 1996, Public Domain
+MODIFIED:
+ 960327: Creation (addition of randinit, really)
+ 970719: use context, not global variables, for internal state
+ 980324: renamed seed to flag
+ 980605: recommend RANDSIZL=4 for noncryptography.
+ 010626: note this is public domain
+------------------------------------------------------------------------------
+*/
+#ifndef RAND
+#define RAND
+
+#include "isaac_standard.h"
+
+/* context of random number generator */
+struct randctx
+{
+ ub4 randcnt;
+ ub4 randrsl[RANDSIZ];
+ ub4 randmem[RANDSIZ];
+ ub4 randa;
+ ub4 randb;
+ ub4 randc;
+};
+typedef struct randctx randctx;
+
+/*
+------------------------------------------------------------------------------
+ If (flag==TRUE), then use the contents of randrsl[0..RANDSIZ-1] as the seed.
+------------------------------------------------------------------------------
+*/
+void randinit(/*_ randctx *r, word flag _*/);
+
+void isaac(/*_ randctx *r _*/);
+
+
+/*
+------------------------------------------------------------------------------
+ Call rand(/o_ randctx *r _o/) to retrieve a single 32-bit random value
+------------------------------------------------------------------------------
+*/
+#define isaac_rand(r) \
+ (!(r)->randcnt-- ? \
+ (isaac(r), (r)->randcnt=RANDSIZ-1, (r)->randrsl[(r)->randcnt]) : \
+ (r)->randrsl[(r)->randcnt])
+
+#endif /* RAND */
+
+