/* Based on corrpcg.c, written in 2018 by Sebastiano Vigna (vigna@acm.org)
   adapted for Xoshiro by Melissa O'Neill (oneill@acm.org)

Generates two correlated sets of outputs using Xoshiro256** generators.

See <http://creativecommons.org/publicdomain/zero/1.0/>. */


#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>


static inline uint64_t rotl(const uint64_t x, int k) {
	return (x << k) | (x >> (64 - k));
}


static inline uint64_t next(uint64_t s[4]) {
	const uint64_t result_starstar = rotl(s[1] * 5, 7) * 9;
	
	const uint64_t t = s[1] << 17;
	
	s[2] ^= s[0];
	s[3] ^= s[1];
	s[1] ^= s[2];
	s[0] ^= s[3];
	
	s[2] ^= t;
	
	s[3] = rotl(s[3], 45);
	
	return result_starstar;
}

int main(int argc, char* argv[]) {
	// Seed data fresh from /dev/random
	uint64_t xo1[4] = { 0x100eeaf0461d14bb, 0xc67ba3a655084ee9,
			    0xcd64d86f417ed16f, 0x125247c9fa0e6ed0 };
	// More random-looking seed data
	uint64_t xo2[4] = { 0xe874f9b004b1beaf, 0x7ddf99501670f4ab, 
			    0x4db1ee8a7057915e, 0xe11fec18143a962f };
	
	for(;;) {
	        uint64_t out = next(xo1);
		fwrite(&out, sizeof out, 1, stdout);
		//printf("%016llx\n", out);
		out = next(xo2);
		fwrite(&out, sizeof out, 1, stdout);
		//printf("%016llx\n", out);
	}
}