//! Random data generation with `arc4random_buf`.
//!
//! Contrary to its name, `arc4random` doesn't actually use the horribly-broken
//! RC4 cypher anymore, at least not on modern systems, but rather something
//! like ChaCha20 with continual reseeding from the OS. That makes it an ideal
//! source of large quantities of cryptographically secure data, which is
//! exactly what we need for `SystemRng`. Unfortunately, it's not available on
//! all UNIX systems, most notably Linux (until recently, but it's just a
//! wrapper for `getrandom`. Since we need to hook into `getrandom` directly for
//! `HashMap` keys anyway, we just keep our version).

#[cfg(not(target_os = "vita"))]
use libc::arc4random_buf;

// FIXME: move this to libc
#[cfg(target_os = "vita")] // See https://github.com/vitasdk/newlib/blob/b89e5bc183b516945f9ee07eef483ecb916e45ff/newlib/libc/include/stdlib.h#L74
unsafe extern "C" {
    fn arc4random_buf(buf: *mut core::ffi::c_void, nbytes: libc::size_t);
}

pub fn fill_bytes(bytes: &mut [u8]) {
    unsafe { arc4random_buf(bytes.as_mut_ptr().cast(), bytes.len()) }
}