diff options
Diffstat (limited to 'rand/src/rngs/adapter/read.rs')
-rw-r--r-- | rand/src/rngs/adapter/read.rs | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/rand/src/rngs/adapter/read.rs b/rand/src/rngs/adapter/read.rs deleted file mode 100644 index 30b6de6..0000000 --- a/rand/src/rngs/adapter/read.rs +++ /dev/null @@ -1,137 +0,0 @@ -// Copyright 2018 Developers of the Rand project. -// Copyright 2013 The Rust Project Developers. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -//! A wrapper around any Read to treat it as an RNG. - -use std::io::Read; - -use rand_core::{RngCore, Error, ErrorKind, impls}; - - -/// An RNG that reads random bytes straight from any type supporting -/// `std::io::Read`, for example files. -/// -/// This will work best with an infinite reader, but that is not required. -/// -/// This can be used with `/dev/urandom` on Unix but it is recommended to use -/// [`OsRng`] instead. -/// -/// # Panics -/// -/// `ReadRng` uses `std::io::read_exact`, which retries on interrupts. All other -/// errors from the underlying reader, including when it does not have enough -/// data, will only be reported through [`try_fill_bytes`]. The other -/// [`RngCore`] methods will panic in case of an error. -/// -/// # Example -/// -/// ``` -/// use rand::Rng; -/// use rand::rngs::adapter::ReadRng; -/// -/// let data = vec![1, 2, 3, 4, 5, 6, 7, 8]; -/// let mut rng = ReadRng::new(&data[..]); -/// println!("{:x}", rng.gen::<u32>()); -/// ``` -/// -/// [`OsRng`]: ../struct.OsRng.html -/// [`RngCore`]: ../../trait.RngCore.html -/// [`try_fill_bytes`]: ../../trait.RngCore.html#method.tymethod.try_fill_bytes -#[derive(Debug)] -pub struct ReadRng<R> { - reader: R -} - -impl<R: Read> ReadRng<R> { - /// Create a new `ReadRng` from a `Read`. - pub fn new(r: R) -> ReadRng<R> { - ReadRng { - reader: r - } - } -} - -impl<R: Read> RngCore for ReadRng<R> { - fn next_u32(&mut self) -> u32 { - impls::next_u32_via_fill(self) - } - - fn next_u64(&mut self) -> u64 { - impls::next_u64_via_fill(self) - } - - fn fill_bytes(&mut self, dest: &mut [u8]) { - self.try_fill_bytes(dest).unwrap_or_else(|err| - panic!("reading random bytes from Read implementation failed; error: {}", err)); - } - - fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - if dest.len() == 0 { return Ok(()); } - // Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`. - self.reader.read_exact(dest).map_err(|err| { - match err.kind() { - ::std::io::ErrorKind::UnexpectedEof => Error::with_cause( - ErrorKind::Unavailable, - "not enough bytes available, reached end of source", err), - _ => Error::with_cause(ErrorKind::Unavailable, - "error reading from Read source", err) - } - }) - } -} - -#[cfg(test)] -mod test { - use super::ReadRng; - use {RngCore, ErrorKind}; - - #[test] - fn test_reader_rng_u64() { - // transmute from the target to avoid endianness concerns. - let v = vec![0u8, 0, 0, 0, 0, 0, 0, 1, - 0 , 0, 0, 0, 0, 0, 0, 2, - 0, 0, 0, 0, 0, 0, 0, 3]; - let mut rng = ReadRng::new(&v[..]); - - assert_eq!(rng.next_u64(), 1_u64.to_be()); - assert_eq!(rng.next_u64(), 2_u64.to_be()); - assert_eq!(rng.next_u64(), 3_u64.to_be()); - } - - #[test] - fn test_reader_rng_u32() { - let v = vec![0u8, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3]; - let mut rng = ReadRng::new(&v[..]); - - assert_eq!(rng.next_u32(), 1_u32.to_be()); - assert_eq!(rng.next_u32(), 2_u32.to_be()); - assert_eq!(rng.next_u32(), 3_u32.to_be()); - } - - #[test] - fn test_reader_rng_fill_bytes() { - let v = [1u8, 2, 3, 4, 5, 6, 7, 8]; - let mut w = [0u8; 8]; - - let mut rng = ReadRng::new(&v[..]); - rng.fill_bytes(&mut w); - - assert!(v == w); - } - - #[test] - fn test_reader_rng_insufficient_bytes() { - let v = [1u8, 2, 3, 4, 5, 6, 7, 8]; - let mut w = [0u8; 9]; - - let mut rng = ReadRng::new(&v[..]); - - assert!(rng.try_fill_bytes(&mut w).err().unwrap().kind == ErrorKind::Unavailable); - } -} |