57 lines
1.5 KiB
Rust
57 lines
1.5 KiB
Rust
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use io;
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use rand::Rng;
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// FIXME: Use rand:
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pub struct OsRng {
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state: [u64; 2]
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}
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impl OsRng {
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/// Create a new `OsRng`.
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pub fn new() -> io::Result<OsRng> {
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Ok(OsRng {
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state: [0xBADF00D1, 0xDEADBEEF]
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})
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}
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}
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impl Rng for OsRng {
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fn next_u32(&mut self) -> u32 {
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self.next_u64() as u32
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}
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fn next_u64(&mut self) -> u64 {
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// Store the first and second part.
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let mut x = self.state[0];
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let y = self.state[1];
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// Put the second part into the first slot.
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self.state[0] = y;
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// Twist the first slot.
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x ^= x << 23;
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// Update the second slot.
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self.state[1] = x ^ y ^ (x >> 17) ^ (y >> 26);
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// Generate the final integer.
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self.state[1].wrapping_add(y)
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}
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fn fill_bytes(&mut self, buf: &mut [u8]) {
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for chunk in buf.chunks_mut(8) {
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let mut rand: u64 = self.next_u64();
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for b in chunk.iter_mut() {
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*b = rand as u8;
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rand = rand >> 8;
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}
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}
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}
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}
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