Remove duplicate code

src/splitmix/dune

@@ -1,9 +1,15 @@
 (library
  (name splitmix)
- (foreign_stubs (language c) (names reference stubs))
+ (foreign_archives splitmix)
+ (foreign_stubs (language c) (names stubs))
  (libraries makeRandom)
  (modules :standard \ Tests))
 
+(foreign_library
+ (archive_name splitmix)
+ (language c)
+ (names reference))
+
 (test
  (name tests)
  (modules Tests)

src/splitmix/reference.c

@@ -2,12 +2,20 @@
 
 #include <stdint.h>
 
-uint64_t sm64_state; /* The state can be seeded with any value. */
-
-uint64_t sm64_next() {
-	uint64_t z = (sm64_state += 0x9e3779b97f4a7c15);
+uint64_t sm64_next_stateless(uint64_t* s) {
+	uint64_t z = (*s += 0x9e3779b97f4a7c15);
 	z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
 	z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
 	return z ^ (z >> 31);
 }
 
+static uint64_t state; /* The state can be seeded with any value. */
+
+void sm64_seed(uint64_t seed) {
+  state = seed;
+}
+
+uint64_t sm64_next() {
+  return sm64_next_stateless(&state);
+}
+

src/splitmix/reference.h

@@ -3,7 +3,9 @@
 
 #include <stdint.h>
 
-uint64_t sm64_state;
+uint64_t sm64_next_stateless(uint64_t*);
+
+void sm64_seed(uint64_t);
 uint64_t sm64_next();
 
 #endif

src/splitmix/stubs.c

@@ -1,15 +1,16 @@
+#include <stdint.h>
+#include "reference.h"
+
 #define CAML_NAME_SPACE
 #include <caml/mlvalues.h>
 #include <caml/memory.h>
 #include <caml/alloc.h>
-#include <stdint.h>
-#include "reference.h"
 
 CAMLprim value caml_sm64_seed(value seed) {
   CAMLparam1(seed);
   int64_t x = Int64_val(seed);
   // reinterpret x as an unsigned integer
-  sm64_state = *(uint64_t*)(&x);
+  sm64_seed(*(uint64_t*)(&x));
   CAMLreturn(Val_unit);
 }
 

src/xoshiro/dune

@@ -1,3 +1,10 @@
 (library
  (name xoshiro)
- (foreign_stubs (language c) (names stubs reference)))
+ (foreign_archives xoshiro)
+ (foreign_stubs (language c) (names stubs)))
+
+(foreign_library
+ (archive_name xoshiro)
+ (language c)
+ (flags -lsplitmix)
+ (names reference))

src/xoshiro/reference.c

@@ -1,6 +1,7 @@
 // Reference:  http://prng.di.unimi.it/xoshiro256plusplus.c
 
 #include <stdint.h>
+#include "../splitmix/reference.h"
 
 static inline uint64_t rotl(const uint64_t x, int k) {
 	return (x << k) | (x >> (64 - k));
@@ -30,16 +31,9 @@ uint64_t x256pp_next(void) {
 	return result;
 }
 
-static uint64_t splitmix64(uint64_t* s) {
-	uint64_t z = (*s += 0x9e3779b97f4a7c15);
-	z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
-	z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
-	return z ^ (z >> 31);
-}
-
 void x256pp_seed(uint64_t seed) {
   uint64_t s = seed;
   for (int i = 0; i < 4; i++)
-    x256pp_state[i] = splitmix64(&s);
+    x256pp_state[i] = sm64_next_stateless(&s);
 }