randxoshiro

• Use xoshiro256++ PRNG to generate random numbers in C with a header-only library.
• Write random bytes to a binary file using the CLI tool.

Header-Only Library

#define RANDWRITE_IMPLEMENTATION
#include "randxoshiro.h"

#include <stdio.h>
#include <time.h>

int main(void)
{
    xo_state state = {0};
    srand_xo(&state, time(0)); // prefer to use stronger seed than time(0)

    printf("Random number: %lld \n", (int64_t)rand_xo(&state));

    return 0;
}

CLI

Build

• Build with command below or run rwcli.bat

gcc rwcli.c -o rwcli.exe -O3 -s

Usage

• To write 10 random 64 bit numbers (80 random bytes) to specified path myfileee, run:

./rwcli 10 -o myfileee

Details

• The CLI tool currently doesn't write "numbers" to a file, it writes randomized bytes directly. This allows easy reinterpration of the same random data e.g. as u64's or as i64's as u32's.
• Xoshiro256++ PRNG's state is initialized using splitmax64 PRNG to satisfy xoshiro256++ no-zero's requirement. The splitmax64 PRNG's state itself is currently only seeded with time(0) in the CLI demo.
• When the CLI program receives a command to e.g. write 100 random numbers to a file, it internally malloc's 100 * 8 bytes to create a buffer that can hold the requested amount of 64 bit numbers.

TODO

• Add "number" writing instead of byte writing, specified via flag.
  • Add float writing support. (culling invalid floats?)
• Initialize splitmax64 with a stronger seed.