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// Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use io;
use mem;
use rand::Rng;
use sys::c;
pub struct OsRng;
impl OsRng {
/// Create a new `OsRng`.
pub fn new() -> io::Result<OsRng> {
Ok(OsRng)
}
}
impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
let mut v = [0; 4];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn next_u64(&mut self) -> u64 {
let mut v = [0; 8];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn fill_bytes(&mut self, v: &mut [u8]) {
// RtlGenRandom takes an ULONG (u32) for the length so we need to
// split up the buffer.
for slice in v.chunks_mut(<c::ULONG>::max_value() as usize) {
let ret = unsafe {
c::RtlGenRandom(slice.as_mut_ptr(), slice.len() as c::ULONG)
};
if ret == 0 {
panic!("couldn't generate random bytes: {}",
io::Error::last_os_error());
}
}
}
}
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