openethereum/util/src/bytes.rs

290 lines
7.1 KiB
Rust
Raw Normal View History

2015-11-28 03:58:37 +01:00
//! Unified interfaces for bytes operations on basic types
2015-12-26 15:48:41 +01:00
//!
2015-11-25 02:53:35 +01:00
//! # Examples
2015-11-28 03:58:37 +01:00
//! ```rust
//! extern crate ethcore_util as util;
2015-12-26 15:48:41 +01:00
//!
2015-11-28 03:58:37 +01:00
//! fn bytes_convertable() {
//! use util::bytes::BytesConvertable;
//!
//! let arr = [0; 5];
//! let slice: &[u8] = arr.bytes();
//! }
2015-12-26 15:48:41 +01:00
//!
2015-11-28 03:58:37 +01:00
//! fn main() {
//! bytes_convertable();
//! }
//! ```
2015-11-25 02:53:35 +01:00
use std::fmt;
2016-01-08 11:02:32 +01:00
use std::slice;
2016-01-13 15:14:24 +01:00
use std::ops::{Deref, DerefMut};
use hash::FixedHash;
2016-01-27 12:14:57 +01:00
use elastic_array::*;
2015-11-25 02:53:35 +01:00
2016-01-27 12:14:57 +01:00
/// Vector like object
pub trait VecLike<T> {
/// Add an element to the collection
2016-01-27 16:58:22 +01:00
fn vec_push(&mut self, value: T);
2016-01-27 12:14:57 +01:00
/// Add a slice to the collection
2016-01-27 16:58:22 +01:00
fn vec_extend(&mut self, slice: &[T]);
2016-01-27 12:14:57 +01:00
}
2016-01-27 16:58:22 +01:00
impl<T> VecLike<T> for Vec<T> where T: Copy {
fn vec_push(&mut self, value: T) {
Vec::<T>::push(self, value)
}
fn vec_extend(&mut self, slice: &[T]) {
Vec::<T>::extend_from_slice(self, slice)
}
}
2016-01-27 12:14:57 +01:00
macro_rules! impl_veclike_for_elastic_array {
($from: ident) => {
impl<T> VecLike<T> for $from<T> where T: Copy {
2016-01-27 16:58:22 +01:00
fn vec_push(&mut self, value: T) {
2016-01-27 12:14:57 +01:00
$from::<T>::push(self, value)
}
2016-01-27 16:58:22 +01:00
fn vec_extend(&mut self, slice: &[T]) {
2016-01-27 12:14:57 +01:00
$from::<T>::append_slice(self, slice)
}
}
}
}
impl_veclike_for_elastic_array!(ElasticArray16);
impl_veclike_for_elastic_array!(ElasticArray32);
impl_veclike_for_elastic_array!(ElasticArray1024);
/// Slie pretty print helper
2015-12-01 18:25:18 +01:00
pub struct PrettySlice<'a> (&'a [u8]);
impl<'a> fmt::Debug for PrettySlice<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
for i in 0..self.0.len() {
2015-12-01 19:09:48 +01:00
match i > 0 {
true => { try!(write!(f, "·{:02x}", self.0[i])); },
false => { try!(write!(f, "{:02x}", self.0[i])); },
}
2015-12-01 18:25:18 +01:00
}
Ok(())
}
}
impl<'a> fmt::Display for PrettySlice<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
for i in 0..self.0.len() {
try!(write!(f, "{:02x}", self.0[i]));
}
Ok(())
}
}
2016-02-03 13:20:32 +01:00
/// Trait to allow a type to be pretty-printed in `format!`, where unoverridable
/// defaults cannot otherwise be avoided.
2015-12-01 18:25:18 +01:00
pub trait ToPretty {
2016-02-03 13:20:32 +01:00
/// Convert a type into a derivative form in order to make `format!` print it prettily.
2015-12-01 18:25:18 +01:00
fn pretty(&self) -> PrettySlice;
2016-02-03 13:20:32 +01:00
/// Express the object as a hex string.
fn to_hex(&self) -> String {
format!("{}", self.pretty())
}
2015-12-01 18:25:18 +01:00
}
impl<'a> ToPretty for &'a [u8] {
fn pretty(&self) -> PrettySlice {
PrettySlice(self)
}
}
impl<'a> ToPretty for &'a Bytes {
fn pretty(&self) -> PrettySlice {
PrettySlice(self.bytes())
}
}
impl ToPretty for Bytes {
fn pretty(&self) -> PrettySlice {
PrettySlice(self.bytes())
}
}
2016-02-03 16:43:48 +01:00
/// A byte collection reference that can either be a slice or a vector
2016-01-13 15:14:24 +01:00
pub enum BytesRef<'a> {
2016-02-03 16:43:48 +01:00
/// This is a reference to a vector
2016-01-13 15:14:24 +01:00
Flexible(&'a mut Bytes),
2016-02-03 16:43:48 +01:00
/// This is a reference to a slice
2016-01-13 15:14:24 +01:00
Fixed(&'a mut [u8])
}
impl<'a> Deref for BytesRef<'a> {
type Target = [u8];
fn deref(&self) -> &[u8] {
2016-01-19 12:14:29 +01:00
match *self {
BytesRef::Flexible(ref bytes) => bytes,
BytesRef::Fixed(ref bytes) => bytes
2016-01-13 15:14:24 +01:00
}
}
}
impl <'a> DerefMut for BytesRef<'a> {
fn deref_mut(&mut self) -> &mut [u8] {
2016-01-19 12:14:29 +01:00
match *self {
BytesRef::Flexible(ref mut bytes) => bytes,
BytesRef::Fixed(ref mut bytes) => bytes
2016-01-13 15:14:24 +01:00
}
}
}
2015-11-28 03:58:37 +01:00
/// Vector of bytes
2015-11-28 00:14:40 +01:00
pub type Bytes = Vec<u8>;
2015-11-28 03:58:37 +01:00
/// Slice of bytes to underlying memory
2015-11-27 17:54:33 +01:00
pub trait BytesConvertable {
2016-01-05 19:05:51 +01:00
// TODO: rename to as_slice
2016-02-03 13:20:32 +01:00
/// Get the underlying byte-wise representation of the value.
/// Deprecated - use `as_slice` instead.
2015-11-27 17:54:33 +01:00
fn bytes(&self) -> &[u8];
2016-02-03 13:20:32 +01:00
/// Get the underlying byte-wise representation of the value.
2016-01-05 19:05:51 +01:00
fn as_slice(&self) -> &[u8] { self.bytes() }
2016-02-03 13:20:32 +01:00
/// Get a copy of the underlying byte-wise representation.
2016-01-05 19:05:51 +01:00
fn to_bytes(&self) -> Bytes { self.as_slice().to_vec() }
2015-11-27 17:54:33 +01:00
}
impl<'a> BytesConvertable for &'a [u8] {
fn bytes(&self) -> &[u8] { self }
}
impl BytesConvertable for Vec<u8> {
fn bytes(&self) -> &[u8] { self }
}
macro_rules! impl_bytes_convertable_for_array {
2016-01-12 17:40:55 +01:00
($zero: expr) => ();
($len: expr, $($idx: expr),*) => {
impl BytesConvertable for [u8; $len] {
fn bytes(&self) -> &[u8] { self }
}
impl_bytes_convertable_for_array! { $($idx),* }
}
}
2015-11-27 18:18:49 +01:00
// -1 at the end is not expanded
impl_bytes_convertable_for_array! {
2016-01-12 17:40:55 +01:00
32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16,
15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, -1
}
2015-11-27 17:54:33 +01:00
#[test]
fn bytes_convertable() {
assert_eq!(vec![0x12u8, 0x34].bytes(), &[0x12u8, 0x34]);
2016-01-12 17:40:55 +01:00
assert_eq!([0u8; 0].bytes(), &[]);
2015-11-27 17:54:33 +01:00
}
/// Simple trait to allow for raw population of a Sized object from a byte slice.
pub trait Populatable {
2016-01-08 11:02:32 +01:00
/// Copies a bunch of bytes `d` to `self`, overwriting as necessary.
///
/// If `d` is smaller, zero-out the remaining bytes.
2016-01-08 11:43:11 +01:00
fn populate_raw(&mut self, d: &[u8]) {
let mut s = self.as_slice_mut();
for i in 0..s.len() {
s[i] = if i < d.len() {d[i]} else {0};
}
}
2016-01-08 11:02:32 +01:00
/// Copies a bunch of bytes `d` to `self`, overwriting as necessary.
///
/// If `d` is smaller, will leave some bytes untouched.
2016-01-08 12:05:38 +01:00
fn copy_raw(&mut self, d: &[u8]) {
2016-01-08 11:43:11 +01:00
use std::io::Write;
self.as_slice_mut().write(&d).unwrap();
}
/// Copies the raw representation of an object `d` to `self`, overwriting as necessary.
///
/// If `d` is smaller, zero-out the remaining bytes.
fn populate_raw_from(&mut self, d: &BytesConvertable) { self.populate_raw(d.as_slice()); }
/// Copies the raw representation of an object `d` to `self`, overwriting as necessary.
///
/// If `d` is smaller, will leave some bytes untouched.
2016-01-08 12:05:38 +01:00
fn copy_raw_from(&mut self, d: &BytesConvertable) { self.copy_raw(d.as_slice()); }
2016-01-08 11:43:11 +01:00
/// Get the raw slice for this object.
fn as_slice_mut(&mut self) -> &mut [u8];
}
impl<T> Populatable for T where T: Sized {
2016-01-08 11:43:11 +01:00
fn as_slice_mut(&mut self) -> &mut [u8] {
use std::mem;
unsafe {
slice::from_raw_parts_mut(self as *mut T as *mut u8, mem::size_of::<T>())
2016-01-08 11:43:11 +01:00
}
}
}
2016-01-08 11:02:32 +01:00
2016-01-08 11:43:11 +01:00
impl<T> Populatable for [T] where T: Sized {
fn as_slice_mut(&mut self) -> &mut [u8] {
2016-01-08 11:02:32 +01:00
use std::mem;
unsafe {
2016-01-08 11:43:11 +01:00
slice::from_raw_parts_mut(self.as_mut_ptr() as *mut u8, mem::size_of::<T>() * self.len())
}
}
}
2016-01-08 11:02:32 +01:00
#[test]
2016-01-08 11:43:11 +01:00
fn fax_raw() {
2016-01-08 11:02:32 +01:00
let mut x = [255u8; 4];
2016-01-08 12:05:38 +01:00
x.copy_raw(&[1u8; 2][..]);
2016-01-08 11:02:32 +01:00
assert_eq!(x, [1u8, 1, 255, 255]);
2016-01-08 11:43:11 +01:00
let mut x = [255u8; 4];
2016-01-08 12:05:38 +01:00
x.copy_raw(&[1u8; 6][..]);
2016-01-08 11:02:32 +01:00
assert_eq!(x, [1u8, 1, 1, 1]);
}
#[test]
fn populate_raw() {
let mut x = [255u8; 4];
x.populate_raw(&[1u8; 2][..]);
assert_eq!(x, [1u8, 1, 0, 0]);
2016-01-08 11:43:11 +01:00
let mut x = [255u8; 4];
2016-01-08 11:02:32 +01:00
x.populate_raw(&[1u8; 6][..]);
assert_eq!(x, [1u8, 1, 1, 1]);
2016-01-08 11:43:11 +01:00
}
#[test]
fn populate_raw_dyn() {
let mut x = [255u8; 4];
x.populate_raw(&[1u8; 2][..]);
assert_eq!(&x[..], [1u8, 1, 0, 0]);
let mut x = [255u8; 4];
x.populate_raw(&[1u8; 6][..]);
assert_eq!(&x[..], [1u8, 1, 1, 1]);
}
#[test]
fn fax_raw_dyn() {
let mut x = [255u8; 4];
2016-01-08 12:05:38 +01:00
x.copy_raw(&[1u8; 2][..]);
2016-01-08 11:43:11 +01:00
assert_eq!(&x[..], [1u8, 1, 255, 255]);
let mut x = [255u8; 4];
2016-01-08 12:05:38 +01:00
x.copy_raw(&[1u8; 6][..]);
2016-01-08 11:43:11 +01:00
assert_eq!(&x[..], [1u8, 1, 1, 1]);
}
#[test]
fn populate_big_types() {
use hash::*;
let a = address_from_hex("ffffffffffffffffffffffffffffffffffffffff");
let mut h = h256_from_u64(0x69);
h.populate_raw_from(&a);
assert_eq!(h, h256_from_hex("ffffffffffffffffffffffffffffffffffffffff000000000000000000000000"));
let mut h = h256_from_u64(0x69);
2016-01-08 12:05:38 +01:00
h.copy_raw_from(&a);
assert_eq!(h, h256_from_hex("ffffffffffffffffffffffffffffffffffffffff000000000000000000000069"));
2016-01-13 15:14:24 +01:00
}