Create single state struct and add utility function for initialising it

xorshift.c

@@ -9,14 +9,7 @@ typedef struct {
 	u64 y;
 	u64 z;
 	u64 w;
-} XORShift256;
-
-typedef struct {
-  u64 x;
-  u64 y;
-  u64 z;
-  u64 w;
-} XOShiRo256SS;
+} XOR256State;
 
 typedef u64(RandGenFunc)(void *s);
 
@@ -25,6 +18,7 @@ u64 xorshift_256_generate(void *s);
 void test_xoshiro_256ss(Image *img);
 u64 xoshiro_256ss_generate(void *s);
 u64 rol64(u64 x, u64 bits);
+XOR256State init_xor_256_state();
 void write_image_data(Image *img, RandGenFunc *gen_rand, void *s);
 
 int main(int argc, char *argv[]) {
@@ -54,18 +48,12 @@ int main(int argc, char *argv[]) {
 }
 
 void test_xorshift_256(Image *img) {
-  XORShift256 state = {
-      .x = lrand48(),
-      .y = lrand48(),
-      .z = lrand48(),
-      .w = lrand48(),
-  };
-
+  XOR256State state = init_xor_256_state();
   write_image_data(img, xorshift_256_generate, (void *)&state);
 }
 
 u64 xorshift_256_generate(void *s) {
-  XORShift256 *state = (XORShift256 *)s;
+  XOR256State *state = (XOR256State *)s;
 
   u64 t = state->x ^ (state->x << 11);
 
@@ -78,18 +66,12 @@ u64 xorshift_256_generate(void *s) {
 }
 
 void test_xoshiro_256ss(Image *img) {
-  XOShiRo256SS state = {
-      .x = lrand48(),
-      .y = lrand48(),
-      .z = lrand48(),
-      .w = lrand48(),
-  };
-
+  XOR256State state = init_xor_256_state();
   write_image_data(img, xoshiro_256ss_generate, (void *)&state);
 }
 
 u64 xoshiro_256ss_generate(void *s) {
-  XOShiRo256SS *state = (XOShiRo256SS *)s;
+  XOR256State *state = (XOR256State *)s;
 
   const u64 result = rol64(state->z * 5, 7) * 9;
   const u64 t = state->z << 17;
@@ -107,6 +89,15 @@ u64 xoshiro_256ss_generate(void *s) {
 
 u64 rol64(u64 x, u64 bits) { return (x << bits) | (x >> (64 - bits)); }
 
+XOR256State init_xor_256_state() {
+	return (XOR256State){
+      .x = lrand48(),
+      .y = lrand48(),
+      .z = lrand48(),
+      .w = lrand48(),
+	};
+}
+
 void write_image_data(Image *img, RandGenFunc *gen_rand, void *s) {
   for (u64 y = 0; y < img->height; ++y) {
     for (u64 x = 0; x < img->width; ++x) {