429 lines
15 KiB
Rust
429 lines
15 KiB
Rust
// Copyright 2012-2013 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 std::num::{One, Zero, CheckedAdd};
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use std::vec::bytes::{MutableByteVector, copy_memory};
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/// Write a u64 into a vector, which must be 8 bytes long. The value is written in big-endian
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/// format.
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pub fn write_u64_be(dst: &mut[u8], input: u64) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_be64;
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assert!(dst.len() == 8);
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unsafe {
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let x: *mut i64 = transmute(dst.unsafe_mut_ref(0));
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*x = to_be64(input as i64);
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}
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}
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/// Write a u32 into a vector, which must be 4 bytes long. The value is written in big-endian
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/// format.
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pub fn write_u32_be(dst: &mut[u8], input: u32) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_be32;
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assert!(dst.len() == 4);
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unsafe {
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let x: *mut i32 = transmute(dst.unsafe_mut_ref(0));
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*x = to_be32(input as i32);
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}
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}
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/// Write a u32 into a vector, which must be 4 bytes long. The value is written in little-endian
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/// format.
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pub fn write_u32_le(dst: &mut[u8], input: u32) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_le32;
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assert!(dst.len() == 4);
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unsafe {
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let x: *mut i32 = transmute(dst.unsafe_mut_ref(0));
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*x = to_le32(input as i32);
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}
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}
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/// Read a vector of bytes into a vector of u64s. The values are read in big-endian format.
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pub fn read_u64v_be(dst: &mut[u64], input: &[u8]) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_be64;
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assert!(dst.len() * 8 == input.len());
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unsafe {
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let mut x: *mut i64 = transmute(dst.unsafe_mut_ref(0));
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let mut y: *i64 = transmute(input.unsafe_ref(0));
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for _ in range(0, dst.len()) {
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*x = to_be64(*y);
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x = x.offset(1);
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y = y.offset(1);
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}
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}
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}
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/// Read a vector of bytes into a vector of u32s. The values are read in big-endian format.
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pub fn read_u32v_be(dst: &mut[u32], input: &[u8]) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_be32;
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assert!(dst.len() * 4 == input.len());
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unsafe {
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let mut x: *mut i32 = transmute(dst.unsafe_mut_ref(0));
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let mut y: *i32 = transmute(input.unsafe_ref(0));
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for _ in range(0, dst.len()) {
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*x = to_be32(*y);
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x = x.offset(1);
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y = y.offset(1);
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}
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}
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}
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/// Read a vector of bytes into a vector of u32s. The values are read in little-endian format.
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pub fn read_u32v_le(dst: &mut[u32], input: &[u8]) {
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use std::cast::transmute;
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use std::unstable::intrinsics::to_le32;
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assert!(dst.len() * 4 == input.len());
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unsafe {
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let mut x: *mut i32 = transmute(dst.unsafe_mut_ref(0));
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let mut y: *i32 = transmute(input.unsafe_ref(0));
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for _ in range(0, dst.len()) {
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*x = to_le32(*y);
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x = x.offset(1);
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y = y.offset(1);
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}
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}
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}
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trait ToBits {
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/// Convert the value in bytes to the number of bits, a tuple where the 1st item is the
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/// high-order value and the 2nd item is the low order value.
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fn to_bits(self) -> (Self, Self);
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}
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impl ToBits for u64 {
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fn to_bits(self) -> (u64, u64) {
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return (self >> 61, self << 3);
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}
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}
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/// Adds the specified number of bytes to the bit count. fail!() if this would cause numeric
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/// overflow.
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pub fn add_bytes_to_bits<T: Int + CheckedAdd + ToBits>(bits: T, bytes: T) -> T {
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let (new_high_bits, new_low_bits) = bytes.to_bits();
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if new_high_bits > Zero::zero() {
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fail!("Numeric overflow occured.")
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}
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match bits.checked_add(&new_low_bits) {
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Some(x) => return x,
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None => fail!("Numeric overflow occured.")
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}
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}
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/// Adds the specified number of bytes to the bit count, which is a tuple where the first element is
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/// the high order value. fail!() if this would cause numeric overflow.
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pub fn add_bytes_to_bits_tuple
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<T: Int + Unsigned + CheckedAdd + ToBits>
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(bits: (T, T), bytes: T) -> (T, T) {
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let (new_high_bits, new_low_bits) = bytes.to_bits();
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let (hi, low) = bits;
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// Add the low order value - if there is no overflow, then add the high order values
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// If the addition of the low order values causes overflow, add one to the high order values
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// before adding them.
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match low.checked_add(&new_low_bits) {
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Some(x) => {
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if new_high_bits == Zero::zero() {
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// This is the fast path - every other alternative will rarely occur in practice
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// considering how large an input would need to be for those paths to be used.
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return (hi, x);
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} else {
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match hi.checked_add(&new_high_bits) {
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Some(y) => return (y, x),
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None => fail!("Numeric overflow occured.")
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}
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}
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},
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None => {
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let one: T = One::one();
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let z = match new_high_bits.checked_add(&one) {
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Some(w) => w,
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None => fail!("Numeric overflow occured.")
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};
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match hi.checked_add(&z) {
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// This re-executes the addition that was already performed earlier when overflow
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// occured, this time allowing the overflow to happen. Technically, this could be
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// avoided by using the checked add intrinsic directly, but that involves using
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// unsafe code and is not really worthwhile considering how infrequently code will
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// run in practice. This is the reason that this function requires that the type T
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// be Unsigned - overflow is not defined for Signed types. This function could be
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// implemented for signed types as well if that were needed.
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Some(y) => return (y, low + new_low_bits),
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None => fail!("Numeric overflow occured.")
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}
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}
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}
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}
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/// A FixedBuffer, likes its name implies, is a fixed size buffer. When the buffer becomes full, it
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/// must be processed. The input() method takes care of processing and then clearing the buffer
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/// automatically. However, other methods do not and require the caller to process the buffer. Any
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/// method that modifies the buffer directory or provides the caller with bytes that can be modifies
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/// results in those bytes being marked as used by the buffer.
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pub trait FixedBuffer {
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/// Input a vector of bytes. If the buffer becomes full, process it with the provided
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/// function and then clear the buffer.
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fn input(&mut self, input: &[u8], func: |&[u8]|);
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/// Reset the buffer.
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fn reset(&mut self);
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/// Zero the buffer up until the specified index. The buffer position currently must not be
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/// greater than that index.
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fn zero_until(&mut self, idx: uint);
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/// Get a slice of the buffer of the specified size. There must be at least that many bytes
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/// remaining in the buffer.
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fn next<'s>(&'s mut self, len: uint) -> &'s mut [u8];
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/// Get the current buffer. The buffer must already be full. This clears the buffer as well.
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fn full_buffer<'s>(&'s mut self) -> &'s [u8];
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/// Get the current position of the buffer.
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fn position(&self) -> uint;
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/// Get the number of bytes remaining in the buffer until it is full.
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fn remaining(&self) -> uint;
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/// Get the size of the buffer
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fn size(&self) -> uint;
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}
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macro_rules! impl_fixed_buffer( ($name:ident, $size:expr) => (
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impl FixedBuffer for $name {
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fn input(&mut self, input: &[u8], func: |&[u8]|) {
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let mut i = 0;
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// FIXME: #6304 - This local variable shouldn't be necessary.
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let size = $size;
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// If there is already data in the buffer, copy as much as we can into it and process
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// the data if the buffer becomes full.
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if self.buffer_idx != 0 {
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let buffer_remaining = size - self.buffer_idx;
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if input.len() >= buffer_remaining {
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copy_memory(
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self.buffer.mut_slice(self.buffer_idx, size),
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input.slice_to(buffer_remaining),
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buffer_remaining);
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self.buffer_idx = 0;
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func(self.buffer);
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i += buffer_remaining;
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} else {
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copy_memory(
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self.buffer.mut_slice(self.buffer_idx, self.buffer_idx + input.len()),
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input,
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input.len());
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self.buffer_idx += input.len();
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return;
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}
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}
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// While we have at least a full buffer size chunks's worth of data, process that data
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// without copying it into the buffer
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while input.len() - i >= size {
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func(input.slice(i, i + size));
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i += size;
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}
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// Copy any input data into the buffer. At this point in the method, the ammount of
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// data left in the input vector will be less than the buffer size and the buffer will
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// be empty.
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let input_remaining = input.len() - i;
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copy_memory(
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self.buffer.mut_slice(0, input_remaining),
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input.slice_from(i),
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input.len() - i);
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self.buffer_idx += input_remaining;
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}
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fn reset(&mut self) {
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self.buffer_idx = 0;
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}
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fn zero_until(&mut self, idx: uint) {
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assert!(idx >= self.buffer_idx);
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self.buffer.mut_slice(self.buffer_idx, idx).set_memory(0);
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self.buffer_idx = idx;
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}
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fn next<'s>(&'s mut self, len: uint) -> &'s mut [u8] {
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self.buffer_idx += len;
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return self.buffer.mut_slice(self.buffer_idx - len, self.buffer_idx);
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}
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fn full_buffer<'s>(&'s mut self) -> &'s [u8] {
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assert!(self.buffer_idx == $size);
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self.buffer_idx = 0;
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return self.buffer.slice_to($size);
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}
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fn position(&self) -> uint { self.buffer_idx }
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fn remaining(&self) -> uint { $size - self.buffer_idx }
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fn size(&self) -> uint { $size }
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}
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))
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/// A fixed size buffer of 64 bytes useful for cryptographic operations.
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pub struct FixedBuffer64 {
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priv buffer: [u8, ..64],
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priv buffer_idx: uint,
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}
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impl FixedBuffer64 {
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/// Create a new buffer
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pub fn new() -> FixedBuffer64 {
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return FixedBuffer64 {
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buffer: [0u8, ..64],
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buffer_idx: 0
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};
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}
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}
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impl_fixed_buffer!(FixedBuffer64, 64)
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/// A fixed size buffer of 128 bytes useful for cryptographic operations.
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pub struct FixedBuffer128 {
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priv buffer: [u8, ..128],
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priv buffer_idx: uint,
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}
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impl FixedBuffer128 {
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/// Create a new buffer
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pub fn new() -> FixedBuffer128 {
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return FixedBuffer128 {
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buffer: [0u8, ..128],
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buffer_idx: 0
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};
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}
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}
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impl_fixed_buffer!(FixedBuffer128, 128)
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/// The StandardPadding trait adds a method useful for various hash algorithms to a FixedBuffer
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/// struct.
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pub trait StandardPadding {
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/// Add standard padding to the buffer. The buffer must not be full when this method is called
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/// and is guaranteed to have exactly rem remaining bytes when it returns. If there are not at
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/// least rem bytes available, the buffer will be zero padded, processed, cleared, and then
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/// filled with zeros again until only rem bytes are remaining.
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fn standard_padding(&mut self, rem: uint, func: |&[u8]|);
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}
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impl <T: FixedBuffer> StandardPadding for T {
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fn standard_padding(&mut self, rem: uint, func: |&[u8]|) {
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let size = self.size();
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self.next(1)[0] = 128;
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if self.remaining() < rem {
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self.zero_until(size);
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func(self.full_buffer());
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}
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self.zero_until(size - rem);
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}
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}
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#[cfg(test)]
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pub mod test {
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use std::rand::{IsaacRng, Rng};
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use std::vec;
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use extra::hex::FromHex;
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use super::{add_bytes_to_bits, add_bytes_to_bits_tuple};
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use super::super::digest::Digest;
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/// Feed 1,000,000 'a's into the digest with varying input sizes and check that the result is
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/// correct.
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pub fn test_digest_1million_random<D: Digest>(digest: &mut D, blocksize: uint, expected: &str) {
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let total_size = 1000000;
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let buffer = vec::from_elem(blocksize * 2, 'a' as u8);
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let mut rng = IsaacRng::new_unseeded();
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let mut count = 0;
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digest.reset();
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while count < total_size {
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let next: uint = rng.gen_range(0, 2 * blocksize + 1);
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let remaining = total_size - count;
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let size = if next > remaining { remaining } else { next };
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digest.input(buffer.slice_to(size));
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count += size;
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}
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let result_str = digest.result_str();
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let result_bytes = digest.result_bytes();
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assert_eq!(expected, result_str.as_slice());
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assert_eq!(expected.from_hex().unwrap(), result_bytes);
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}
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// A normal addition - no overflow occurs
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#[test]
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fn test_add_bytes_to_bits_ok() {
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assert!(add_bytes_to_bits::<u64>(100, 10) == 180);
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}
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// A simple failure case - adding 1 to the max value
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#[test]
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#[should_fail]
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fn test_add_bytes_to_bits_overflow() {
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add_bytes_to_bits::<u64>(Bounded::max_value(), 1);
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}
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// A normal addition - no overflow occurs (fast path)
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#[test]
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fn test_add_bytes_to_bits_tuple_ok() {
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assert!(add_bytes_to_bits_tuple::<u64>((5, 100), 10) == (5, 180));
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}
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// The low order value overflows into the high order value
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#[test]
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fn test_add_bytes_to_bits_tuple_ok2() {
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assert!(add_bytes_to_bits_tuple::<u64>((5, Bounded::max_value()), 1) == (6, 7));
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}
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// The value to add is too large to be converted into bits without overflowing its type
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#[test]
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fn test_add_bytes_to_bits_tuple_ok3() {
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assert!(add_bytes_to_bits_tuple::<u64>((5, 0), 0x4000000000000001) == (7, 8));
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}
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// A simple failure case - adding 1 to the max value
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#[test]
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#[should_fail]
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fn test_add_bytes_to_bits_tuple_overflow() {
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add_bytes_to_bits_tuple::<u64>((Bounded::max_value(), Bounded::max_value()), 1);
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}
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// The value to add is too large to convert to bytes without overflowing its type, but the high
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// order value from this conversion overflows when added to the existing high order value
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#[test]
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#[should_fail]
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fn test_add_bytes_to_bits_tuple_overflow2() {
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let value: u64 = Bounded::max_value();
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add_bytes_to_bits_tuple::<u64>((value - 1, 0), 0x8000000000000000);
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}
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}
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