Skip to content

Commit

Permalink
Byte tools update
Browse files Browse the repository at this point in the history
  • Loading branch information
@newpavlov
newpavlov committed Jun 6, 2017
1 parent 5bb9968 commit 12b85f9
Show file tree
Hide file tree
Showing 7 changed files with 175 additions and 354 deletions.
2 changes: 1 addition & 1 deletion byte-tools/Cargo.toml
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
[package]
name = "byte-tools"
version = "0.1.3"
version = "0.2.0"
authors = ["The Rust-Crypto Project Developers"]
license = "MIT/Apache-2.0"
description = "Utility functions for working with bytes"
Expand Down
312 changes: 9 additions & 303 deletions byte-tools/src/lib.rs
View file
Original file line number Diff line number Diff line change
@@ -1,243 +1,15 @@
#![no_std]
use core::{mem, ptr};
use core::ptr;

/// Write a u64 into a vector, which must be 8 bytes long. The value is written
/// in big-endian format.
pub fn write_u64_be(dst: &mut [u8], mut input: u64) {
assert!(dst.len() == 8);
input = input.to_be();
unsafe {
let tmp = &input as *const _ as *const u8;
ptr::copy_nonoverlapping(tmp, dst.get_unchecked_mut(0), 8);
}
}

/// Write a u64 into a vector, which must be 8 bytes long. The value is written
/// in little-endian format.
pub fn write_u64_le(dst: &mut [u8], mut input: u64) {
assert!(dst.len() == 8);
input = input.to_le();
unsafe {
let tmp = &input as *const _ as *const u8;
ptr::copy_nonoverlapping(tmp, dst.get_unchecked_mut(0), 8);
}
}

/// Write a vector of u64s into a vector of bytes. The values are written in
/// little-endian format.
pub fn write_u64v_be(dst: &mut [u8], input: &[u64]) {
assert!(dst.len() == 8 * input.len());
unsafe {
let mut x: *mut u8 = dst.get_unchecked_mut(0);
let mut y: *const u64 = input.get_unchecked(0);
for _ in 0..input.len() {
let tmp = (*y).to_be();
ptr::copy_nonoverlapping(&tmp as *const _ as *const u8, x, 8);
x = x.offset(8);
y = y.offset(1);
}
}
}

/// Write a vector of u64s into a vector of bytes. The values are written in
/// little-endian format.
pub fn write_u64v_le(dst: &mut [u8], input: &[u64]) {
assert!(dst.len() == 8 * input.len());
unsafe {
let mut x: *mut u8 = dst.get_unchecked_mut(0);
let mut y: *const u64 = input.get_unchecked(0);
for _ in 0..input.len() {
let tmp = (*y).to_le();
ptr::copy_nonoverlapping(&tmp as *const _ as *const u8, x, 8);
x = x.offset(8);
y = y.offset(1);
}
}
}
mod read_single;
mod write_single;
mod read_slice;
mod write_slice;

/// Write a u32 into a vector, which must be 4 bytes long. The value is written
/// in big-endian format.
pub fn write_u32_be(dst: &mut [u8], mut input: u32) {
assert!(dst.len() == 4);
input = input.to_be();
unsafe {
let tmp = &input as *const _ as *const u8;
ptr::copy_nonoverlapping(tmp, dst.get_unchecked_mut(0), 4);
}
}

/// Write a u32 into a vector, which must be 4 bytes long. The value is written
/// in little-endian format.
pub fn write_u32_le(dst: &mut [u8], mut input: u32) {
assert!(dst.len() == 4);
input = input.to_le();
unsafe {
let tmp = &input as *const _ as *const u8;
ptr::copy_nonoverlapping(tmp, dst.get_unchecked_mut(0), 4);
}
}

/// Write a vector of u32s into a vector of bytes. The values are written in
/// little-endian format.
pub fn write_u32v_le(dst: &mut [u8], input: &[u32]) {
assert!(dst.len() == 4 * input.len());
unsafe {
let mut x: *mut u8 = dst.get_unchecked_mut(0);
let mut y: *const u32 = input.get_unchecked(0);
for _ in 0..input.len() {
let tmp = (*y).to_le();
ptr::copy_nonoverlapping(&tmp as *const _ as *const u8, x, 4);
x = x.offset(4);
y = y.offset(1);
}
}
}

/// Write a vector of u32s into a vector of bytes. The values are written in
/// big-endian format.
pub fn write_u32v_be(dst: &mut [u8], input: &[u32]) {
assert!(dst.len() == 4 * input.len());
unsafe {
let mut x: *mut u8 = dst.get_unchecked_mut(0);
let mut y: *const u32 = input.get_unchecked(0);
for _ in 0..input.len() {
let tmp = (*y).to_be();
ptr::copy_nonoverlapping(&tmp as *const _ as *const u8, x, 4);
x = x.offset(4);
y = y.offset(1);
}
}
}

/// Read a vector of bytes into a vector of u64s. The values are read in
/// big-endian format.
pub fn read_u64v_be(dst: &mut [u64], input: &[u8]) {
assert!(dst.len() * 8 == input.len());
unsafe {
let mut x: *mut u64 = dst.get_unchecked_mut(0);
let mut y: *const u8 = input.get_unchecked(0);
for _ in 0..dst.len() {
let mut tmp: u64 = mem::uninitialized();
ptr::copy_nonoverlapping(y, &mut tmp as *mut _ as *mut u8, 8);
*x = u64::from_be(tmp);
x = x.offset(1);
y = y.offset(8);
}
}
}

/// Read a vector of bytes into a vector of u64s. The values are read in
/// little-endian format.
pub fn read_u64v_le(dst: &mut [u64], input: &[u8]) {
assert!(dst.len() * 8 == input.len());
unsafe {
let mut x: *mut u64 = dst.get_unchecked_mut(0);
let mut y: *const u8 = input.get_unchecked(0);
for _ in 0..dst.len() {
let mut tmp: u64 = mem::uninitialized();
ptr::copy_nonoverlapping(y, &mut tmp as *mut _ as *mut u8, 8);
*x = u64::from_le(tmp);
x = x.offset(1);
y = y.offset(8);
}
}
}

/// Read a vector of bytes into a vector of u32s. The values are read in
/// big-endian format.
pub fn read_u32v_be(dst: &mut [u32], input: &[u8]) {
assert!(dst.len() * 4 == input.len());
unsafe {
let mut x: *mut u32 = dst.get_unchecked_mut(0);
let mut y: *const u8 = input.get_unchecked(0);
for _ in 0..dst.len() {
let mut tmp: u32 = mem::uninitialized();
ptr::copy_nonoverlapping(y, &mut tmp as *mut _ as *mut u8, 4);
*x = u32::from_be(tmp);
x = x.offset(1);
y = y.offset(4);
}
}
}

/// Read a vector of bytes into a vector of u32s. The values are read in
/// little-endian format.
pub fn read_u32v_le(dst: &mut [u32], input: &[u8]) {
assert!(dst.len() * 4 == input.len());
unsafe {
let mut x: *mut u32 = dst.get_unchecked_mut(0);
let mut y: *const u8 = input.get_unchecked(0);
for _ in 0..dst.len() {
let mut tmp: u32 = mem::uninitialized();
ptr::copy_nonoverlapping(y, &mut tmp as *mut _ as *mut u8, 4);
*x = u32::from_le(tmp);
x = x.offset(1);
y = y.offset(4);
}
}
}

/// Read the value of a vector of bytes as a u32 value in little-endian format.
pub fn read_u32_le(input: &[u8]) -> u32 {
assert!(input.len() == 4);
unsafe {
let mut tmp: u32 = mem::uninitialized();
ptr::copy_nonoverlapping(input.get_unchecked(0),
&mut tmp as *mut _ as *mut u8,
4);
u32::from_le(tmp)
}
}

/// Read the value of a vector of bytes as a u64 value in little-endian format.
pub fn read_u64_le(input: &[u8]) -> u64 {
assert!(input.len() == 8);
unsafe {
let mut tmp: u64 = mem::uninitialized();
ptr::copy_nonoverlapping(input.get_unchecked(0),
&mut tmp as *mut _ as *mut u8,
8);
u64::from_le(tmp)
}
}

/// Read the value of a vector of bytes as a u32 value in big-endian format.
pub fn read_u32_be(input: &[u8]) -> u32 {
assert!(input.len() == 4);
unsafe {
let mut tmp: u32 = mem::uninitialized();
ptr::copy_nonoverlapping(input.get_unchecked(0),
&mut tmp as *mut _ as *mut u8,
4);
u32::from_be(tmp)
}
}

/// Read the value of a vector of bytes as a u64 value in big-endian format.
pub fn read_u64_be(input: &[u8]) -> u64 {
assert!(input.len() == 8);
unsafe {
let mut tmp: u64 = mem::uninitialized();
ptr::copy_nonoverlapping(input.get_unchecked(0),
&mut tmp as *mut _ as *mut u8,
8);
u64::from_be(tmp)
}
}

/// XOR plaintext and keystream, storing the result in dst.
pub fn xor_keystream(dst: &mut [u8], plaintext: &[u8], keystream: &[u8]) {
assert!(dst.len() == plaintext.len());
assert!(plaintext.len() <= keystream.len());

// Do one byte at a time, using unsafe to skip bounds checking.
let p = plaintext.as_ptr();
let k = keystream.as_ptr();
let d = dst.as_mut_ptr();
for i in 0isize..plaintext.len() as isize {
unsafe { *d.offset(i) = *p.offset(i) ^ *k.offset(i) };
}
}
pub use read_single::*;
pub use write_single::*;
pub use read_slice::*;
pub use write_slice::*;

/// Copy bytes from src to dest
#[inline]
Expand All @@ -257,69 +29,3 @@ pub fn zero(dst: &mut [u8]) {
ptr::write_bytes(dst.as_mut_ptr(), 0, dst.len());
}
}

/// Convert the value in bytes to the number of bits, a tuple where the 1st
/// item is the high-order value and the 2nd item is the low order value.
fn to_bits(x: u64) -> (u64, u64) { (x >> 61, x << 3) }

/// Adds the specified number of bytes to the bit count. panic!() if this
/// would cause numeric overflow.
pub fn add_bytes_to_bits(bits: u64, bytes: u64) -> u64 {
let (new_high_bits, new_low_bits) = to_bits(bytes);

if new_high_bits > 0 {
panic!("Numeric overflow occured.")
}

bits.checked_add(new_low_bits).expect("Numeric overflow occured.")
}

/// Adds the specified number of bytes to the bit count, which is a tuple where
/// the first element is the high order value. panic!() if this would cause
/// numeric overflow.
pub fn add_bytes_to_bits_tuple(bits: (u64, u64), bytes: u64) -> (u64, u64) {
let (new_high_bits, new_low_bits) = to_bits(bytes);
let (hi, low) = bits;

// Add the low order value - if there is no overflow, then add the high
// order values. If the addition of the low order values causes overflow,
// add one to the high order values before adding them.
match low.checked_add(new_low_bits) {
Some(x) => {
if new_high_bits == 0 {
// This is the fast path - every other alternative will rarely
// occur in practice considering how large an input would need
// to be for those paths to be used.
(hi, x)
} else {
match hi.checked_add(new_high_bits) {
Some(y) => (y, x),
None => panic!("Numeric overflow occured."),
}
}
},
None => {
let z = match new_high_bits.checked_add(1) {
Some(w) => w,
None => panic!("Numeric overflow occured."),
};
match hi.checked_add(z) {
// This re-executes the addition that was already performed
// earlier when overflow occured, this time allowing the
// overflow to happen. Technically, this could be avoided by
// using the checked add intrinsic directly, but that involves
// using unsafe code and is not really worthwhile considering
// how infrequently code will run in practice. This is the
// reason that this function requires that the type T be
// UnsignedInt - overflow is not defined for Signed types.
// This function could be implemented for signed types as well
// if that were needed.
Some(y) => (y, low.wrapping_add(new_low_bits)),
None => panic!("Numeric overflow occured."),
}
},
}
}

#[cfg(test)]
pub mod tests;
38 changes: 38 additions & 0 deletions byte-tools/src/read_single.rs
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,38 @@
use core::{mem, ptr};

macro_rules! read_single {
($src:expr, $size:expr, $ty:ty, $which:ident) => ({
assert!($size == mem::size_of::<$ty>());
assert!($size == $src.len());
unsafe {
let mut tmp: $ty = mem::uninitialized();
let p = &mut tmp as *mut _ as *mut u8;
ptr::copy_nonoverlapping($src.as_ptr(), p, $size);
tmp.$which()
}
});
}

/// Read the value of a vector of bytes as a u32 value in little-endian format.
#[inline]
pub fn read_u32_le(src: &[u8]) -> u32 {
read_single!(src, 4, u32, to_le)
}

/// Read the value of a vector of bytes as a u32 value in big-endian format.
#[inline]
pub fn read_u32_be(src: &[u8]) -> u32 {
read_single!(src, 4, u32, to_be)
}

/// Read the value of a vector of bytes as a u64 value in little-endian format.
#[inline]
pub fn read_u64_le(src: &[u8]) -> u64 {
read_single!(src, 8, u64, to_le)
}

/// Read the value of a vector of bytes as a u64 value in big-endian format.
#[inline]
pub fn read_u64_be(src: &[u8]) -> u64 {
read_single!(src, 8, u64, to_be)
}
Loading

0 comments on commit 12b85f9

Please sign in to comment.