#include <iostream>

#include <inttypes.h>
#include <algorithm>

static uint32_t rprand_state[4] = {0};
static uint64_t rprand_seed = 0;

static inline uint32_t my_rotate_left(const uint32_t x, int k)
{
  return (x << k) | (x >> (32 - k));
}

uint32_t my_rprand_xoshiro(uint32_t state[4])
{
  const uint32_t result = my_rotate_left(state[1] * 5, 7) * 9;
  const uint32_t t = state[1] << 9;

  state[2] ^= state[0];
  state[3] ^= state[1];
  state[1] ^= state[2];
  state[0] ^= state[3];

  state[2] ^= t;

  state[3] = my_rotate_left(state[3], 11);

  return result;
}

uint64_t rprand_splitmix64()
{
  uint64_t z = (rprand_seed += 0x9e3779b97f4a7c15);
  z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
  z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
  return z ^ (z >> 31);
}

void setSeed(unsigned long long seed)
{
  rprand_seed = (uint64_t)seed; // Set SplitMix64 seed for further use

  // To generate the Xoshiro128** state, we use SplitMix64 generator first
  // We generate 4 pseudo-random 64bit numbers that we combine using their LSB|MSB
  rprand_state[0] = (uint32_t)(rprand_splitmix64() & 0xffffffff);
  rprand_state[1] = (uint32_t)((rprand_splitmix64() & 0xffffffff00000000) >> 32);
  rprand_state[2] = (uint32_t)(rprand_splitmix64() & 0xffffffff);
  rprand_state[3] = (uint32_t)((rprand_splitmix64() & 0xffffffff00000000) >> 32);
}

int getValue(int min, int max)
{
  return my_rprand_xoshiro(rprand_state) % (std::abs(max - min) + 1) + min;
}

double getFloat()
{
  return my_rprand_xoshiro(rprand_state) / (double)UINT32_MAX;
}

typedef uint32_t (*func_t)();
#define N 100

static uint32_t Rand7Naive()
{
  return getValue(0, N - 1);
}

static uint32_t Rand7Float()
{
  return (getFloat() * N);
}

void Test(func_t rand, std::string name)
{
  uint64_t *buckets = new uint64_t[N];
  for (int i = 0; i < N; i++)
    buckets[i] = 0;

  for (int i = 0; i < 100000000; i++)
    buckets[rand()]++;

  uint64_t sum = 0;
  for (int i = 0; i < N; i++)
    sum += buckets[i];

  printf("%s\n", name.c_str());
  for (int i = 0; i < N; i++)
    printf("%d\t%ld\n", i, buckets[i]);

  printf("sum = %ld\n\n", sum);

  delete buckets;
}

int main(int argc, char const *argv[])
{
  setSeed((unsigned int)time(NULL));

  Test(Rand7Naive, "Rand7Naive");
  setSeed((unsigned int)time(NULL));
  Test(Rand7Float, "Rand7Float");

  return 0;
}