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Move bitlist and bitvector into own files

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This commit is contained in:
Paul Hauner 2019-07-08 09:36:52 +10:00
parent c8c5c8ff16
commit ecb0bf11c7
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5 changed files with 749 additions and 749 deletions
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443
eth2/utils/ssz_types/src/bit_list.rs Normal file
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use super::*;
use crate::{impl_bitfield_fns, reverse_bit_order, Error};
use bit_vec::BitVec as Bitfield;
use serde::de::{Deserialize, Deserializer};
use serde::ser::{Serialize, Serializer};
use serde_hex::{encode, PrefixedHexVisitor};
use ssz::{Decode, Encode};
use std::cmp;
use std::default;
use std::marker::PhantomData;
use typenum::Unsigned;
/// Emulates a SSZ `Bitlist`.
///
/// An ordered, heap-allocated, variable-length, collection of `bool` values, limited to `N`
/// values.
///
/// ## Notes
///
/// Considering this struct is backed by bytes, errors may be raised when attempting to decode
/// bytes into a `BitList<N>` where `N` is not a multiple of 8. It is advised to always set `N` to
/// a multiple of 8.
///
/// ## Example
/// ```
/// use ssz_types::{BitList, typenum};
///
/// let mut bitlist: BitList<typenum::U8> = BitList::new();
///
/// assert_eq!(bitlist.len(), 0);
///
/// assert!(bitlist.get(0).is_err()); // Cannot get at or below the length.
///
/// for i in 0..8 {
/// assert!(bitlist.set(i, true).is_ok());
/// }
///
/// assert!(bitlist.set(8, true).is_err()); // Cannot set out-of-bounds.
///
/// // Cannot create with an excessive capacity.
/// let result: Result<BitList<typenum::U8>, _> = BitList::with_capacity(9);
/// assert!(result.is_err());
/// ```
#[derive(Debug, Clone)]
pub struct BitList<N> {
bitfield: Bitfield,
_phantom: PhantomData<N>,
}
impl_bitfield_fns!(BitList);
impl<N: Unsigned> BitList<N> {
/// Create a new, empty BitList.
pub fn new() -> Self {
Self {
bitfield: Bitfield::default(),
_phantom: PhantomData,
}
}
fn validate_length(len: usize) -> Result<(), Error> {
let max_len = Self::max_len();
if len > max_len {
Err(Error::InvalidLength {
i: len,
len: max_len,
})
} else {
Ok(())
}
}
/// The maximum possible number of bits.
pub fn max_len() -> usize {
N::to_usize()
}
}
impl<N: Unsigned + Clone> BitList<N> {
/// Compute the intersection (binary-and) of this bitfield with another
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn intersection(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res: Self = self.to_owned();
res.intersection_inplace(other);
res
}
/// Like `intersection` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn intersection_inplace(&mut self, other: &Self) {
self.bitfield.intersect(&other.bitfield);
}
/// Compute the union (binary-or) of this bitfield with another. Lengths must match.
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn union(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res = self.clone();
res.union_inplace(other);
res
}
/// Like `union` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn union_inplace(&mut self, other: &Self) {
self.bitfield.union(&other.bitfield);
}
/// Compute the difference (binary-minus) of this bitfield with another. Lengths must match.
///
/// Computes `self - other`.
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn difference(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res = self.clone();
res.difference_inplace(other);
res
}
/// Like `difference` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn difference_inplace(&mut self, other: &Self) {
self.bitfield.difference(&other.bitfield);
}
}
impl<N: Unsigned> default::Default for BitList<N> {
/// Default provides the "empty" bitfield
/// Note: the empty bitfield is set to the `0` byte.
fn default() -> Self {
Self::from_elem(0, false).expect("Zero cannot be larger than the maximum length")
}
}
#[cfg(test)]
mod test_bitlist {
use super::*;
use serde_yaml;
use ssz::ssz_encode;
// use tree_hash::TreeHash;
pub type BitList1024 = BitList<typenum::U1024>;
/*
#[test]
pub fn cached_tree_hash() {
let original = BitList1024::from_bytes(&vec![18; 12][..]);
let mut cache = cached_tree_hash::TreeHashCache::new(&original).unwrap();
assert_eq!(
cache.tree_hash_root().unwrap().to_vec(),
original.tree_hash_root()
);
let modified = BitList1024::from_bytes(&vec![2; 1][..]);
cache.update(&modified).unwrap();
assert_eq!(
cache.tree_hash_root().unwrap().to_vec(),
modified.tree_hash_root()
);
}
*/
#[test]
fn new_bitfield() {
let mut field = BitList1024::new();
let original_len = field.len();
for i in 0..100 {
if i < original_len {
assert!(!field.get(i).unwrap());
} else {
assert!(field.get(i).is_err());
}
field.set(i, true).unwrap();
}
}
#[test]
fn empty_bitfield() {
let mut field = BitList1024::from_elem(0, false).unwrap();
let original_len = field.len();
assert_eq!(original_len, 0);
for i in 0..100 {
if i < original_len {
assert!(!field.get(i).unwrap());
} else {
assert!(field.get(i).is_err());
}
field.set(i, true).unwrap();
}
assert_eq!(field.len(), 100);
assert_eq!(field.num_set_bits(), 100);
}
const INPUT: &[u8] = &[0b0100_0000, 0b0100_0000];
#[test]
fn get_from_bitfield() {
let field = BitList1024::from_bytes(INPUT).unwrap();
field.get(0).unwrap();
field.get(6).unwrap();
field.get(14).unwrap();
}
#[test]
fn set_for_bitfield() {
let mut field = BitList1024::from_bytes(INPUT).unwrap();
field.set(10, true).unwrap();
field.get(10).unwrap();
field.set(6, false).unwrap();
field.get(6).unwrap();
}
#[test]
fn len() {
let field = BitList1024::from_bytes(INPUT).unwrap();
assert_eq!(field.len(), 16);
let field = BitList1024::new();
assert_eq!(field.len(), 0);
}
#[test]
fn num_set_bits() {
let field = BitList1024::from_bytes(INPUT).unwrap();
assert_eq!(field.num_set_bits(), 2);
let field = BitList1024::new();
assert_eq!(field.num_set_bits(), 0);
}
#[test]
fn to_bytes() {
let field = BitList1024::from_bytes(INPUT).unwrap();
assert_eq!(field.to_bytes(), INPUT);
let field = BitList1024::new();
assert_eq!(field.to_bytes(), vec![0]);
}
#[test]
fn out_of_bounds() {
let mut field = BitList1024::from_bytes(INPUT).unwrap();
let out_of_bounds_index = field.len();
assert!(field.set(out_of_bounds_index, true).is_ok());
assert!(field.len() == out_of_bounds_index + 1);
assert!(field.get(out_of_bounds_index).unwrap());
for i in 0..100 {
if i <= out_of_bounds_index {
assert!(field.set(i, true).is_ok());
} else {
assert!(field.set(i, true).is_ok());
}
}
}
#[test]
fn grows_with_false() {
let input_all_set: &[u8] = &[0b1111_1111, 0b1111_1111];
let mut field = BitList1024::from_bytes(input_all_set).unwrap();
// Define `a` and `b`, where both are out of bounds and `b` is greater than `a`.
let a = field.len();
let b = a + 1;
// Ensure `a` is out-of-bounds for test integrity.
assert!(field.get(a).is_err());
// Set `b` to `true`..
assert!(field.set(b, true).is_ok());
// Ensure that `a` wasn't also set to `true` during the grow.
assert_eq!(field.get(a), Ok(false));
assert_eq!(field.get(b), Ok(true));
}
#[test]
fn num_bytes() {
let field = BitList1024::from_bytes(INPUT).unwrap();
assert_eq!(field.num_bytes(), 2);
let field = BitList1024::from_elem(2, true).unwrap();
assert_eq!(field.num_bytes(), 1);
let field = BitList1024::from_elem(13, true).unwrap();
assert_eq!(field.num_bytes(), 2);
}
#[test]
fn ssz_encoding() {
let field = create_bitfield();
assert_eq!(field.as_ssz_bytes(), vec![0b0000_0011, 0b1000_0111]);
let field = BitList1024::from_elem(18, true).unwrap();
assert_eq!(
field.as_ssz_bytes(),
vec![0b0000_0011, 0b1111_1111, 0b1111_1111]
);
let mut b = BitList1024::new();
b.set(1, true).unwrap();
assert_eq!(ssz_encode(&b), vec![0b0000_0010]);
}
fn create_bitfield() -> BitList1024 {
let count = 2 * 8;
let mut field = BitList1024::with_capacity(count).unwrap();
let indices = &[0, 1, 2, 7, 8, 9];
for &i in indices {
field.set(i, true).unwrap();
}
field
}
#[test]
fn ssz_decode() {
let encoded = vec![0b0000_0011, 0b1000_0111];
let field = BitList1024::from_ssz_bytes(&encoded).unwrap();
let expected = create_bitfield();
assert_eq!(field, expected);
let encoded = vec![255, 255, 3];
let field = BitList1024::from_ssz_bytes(&encoded).unwrap();
let expected = BitList1024::from_bytes(&[255, 255, 3]).unwrap();
assert_eq!(field, expected);
}
#[test]
fn serialize_deserialize() {
use serde_yaml::Value;
let data: &[(_, &[_])] = &[
("0x01", &[0b00000001]),
("0xf301", &[0b11110011, 0b00000001]),
];
for (hex_data, bytes) in data {
let bitfield = BitList1024::from_bytes(bytes).unwrap();
assert_eq!(
serde_yaml::from_str::<BitList1024>(hex_data).unwrap(),
bitfield
);
assert_eq!(
serde_yaml::to_value(&bitfield).unwrap(),
Value::String(hex_data.to_string())
);
}
}
#[test]
fn ssz_round_trip() {
let original = BitList1024::from_bytes(&vec![18; 12][..]).unwrap();
let ssz = ssz_encode(&original);
let decoded = BitList1024::from_ssz_bytes(&ssz).unwrap();
assert_eq!(original, decoded);
}
#[test]
fn bitor() {
let a = BitList1024::from_bytes(&vec![2, 8, 1][..]).unwrap();
let b = BitList1024::from_bytes(&vec![4, 8, 16][..]).unwrap();
let c = BitList1024::from_bytes(&vec![6, 8, 17][..]).unwrap();
assert_eq!(c, a | b);
}
#[test]
fn is_zero() {
let yes_data: &[&[u8]] = &[&[], &[0], &[0, 0], &[0, 0, 0]];
for bytes in yes_data {
assert!(BitList1024::from_bytes(bytes).unwrap().is_zero());
}
let no_data: &[&[u8]] = &[&[1], &[6], &[0, 1], &[0, 0, 1], &[0, 0, 255]];
for bytes in no_data {
assert!(!BitList1024::from_bytes(bytes).unwrap().is_zero());
}
}
#[test]
fn intersection() {
let a = BitList1024::from_bytes(&[0b1100, 0b0001]).unwrap();
let b = BitList1024::from_bytes(&[0b1011, 0b1001]).unwrap();
let c = BitList1024::from_bytes(&[0b1000, 0b0001]).unwrap();
assert_eq!(a.intersection(&b), c);
assert_eq!(b.intersection(&a), c);
assert_eq!(a.intersection(&c), c);
assert_eq!(b.intersection(&c), c);
assert_eq!(a.intersection(&a), a);
assert_eq!(b.intersection(&b), b);
assert_eq!(c.intersection(&c), c);
}
#[test]
fn union() {
let a = BitList1024::from_bytes(&[0b1100, 0b0001]).unwrap();
let b = BitList1024::from_bytes(&[0b1011, 0b1001]).unwrap();
let c = BitList1024::from_bytes(&[0b1111, 0b1001]).unwrap();
assert_eq!(a.union(&b), c);
assert_eq!(b.union(&a), c);
assert_eq!(a.union(&a), a);
assert_eq!(b.union(&b), b);
assert_eq!(c.union(&c), c);
}
#[test]
fn difference() {
let a = BitList1024::from_bytes(&[0b1100, 0b0001]).unwrap();
let b = BitList1024::from_bytes(&[0b1011, 0b1001]).unwrap();
let a_b = BitList1024::from_bytes(&[0b0100, 0b0000]).unwrap();
let b_a = BitList1024::from_bytes(&[0b0011, 0b1000]).unwrap();
assert_eq!(a.difference(&b), a_b);
assert_eq!(b.difference(&a), b_a);
assert!(a.difference(&a).is_zero());
}
}

69
eth2/utils/ssz_types/src/bit_vector.rs Normal file
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use super::*;
use crate::{impl_bitfield_fns, reverse_bit_order, Error};
use bit_vec::BitVec as Bitfield;
use serde::de::{Deserialize, Deserializer};
use serde::ser::{Serialize, Serializer};
use serde_hex::{encode, PrefixedHexVisitor};
use ssz::{Decode, Encode};
use std::cmp;
use std::marker::PhantomData;
use typenum::Unsigned;
/// Emulates a SSZ `Bitvector`.
///
/// An ordered, heap-allocated, fixed-length, collection of `bool` values, with `N` values.
///
/// ## Notes
///
/// Considering this struct is backed by bytes, errors may be raised when attempting to decode
/// bytes into a `BitVector<N>` where `N` is not a multiple of 8. It is advised to always set `N` to
/// a multiple of 8.
///
/// ## Example
/// ```
/// use ssz_types::{BitVector, typenum};
///
/// let mut bitvec: BitVector<typenum::U8> = BitVector::new();
///
/// assert_eq!(bitvec.len(), 8);
///
/// for i in 0..8 {
/// assert_eq!(bitvec.get(i).unwrap(), false); // Defaults to false.
/// }
///
/// assert!(bitvec.get(8).is_err()); // Cannot get out-of-bounds.
///
/// assert!(bitvec.set(7, true).is_ok());
/// assert!(bitvec.set(8, true).is_err()); // Cannot set out-of-bounds.
/// ```
#[derive(Debug, Clone)]
pub struct BitVector<N> {
bitfield: Bitfield,
_phantom: PhantomData<N>,
}
impl_bitfield_fns!(BitVector);
impl<N: Unsigned> BitVector<N> {
/// Create a new bitfield.
pub fn new() -> Self {
Self::with_capacity(Self::capacity()).expect("Capacity must be correct")
}
fn capacity() -> usize {
N::to_usize()
}
fn validate_length(len: usize) -> Result<(), Error> {
let fixed_len = N::to_usize();
if len > fixed_len {
Err(Error::InvalidLength {
i: len,
len: fixed_len,
})
} else {
Ok(())
}
}
}

747
eth2/utils/ssz_types/src/bitfield.rs
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@ -1,747 +0,0 @@
use crate::Error;
use bit_reverse::LookupReverse;
use bit_vec::BitVec as Bitfield;
use serde::de::{Deserialize, Deserializer};
use serde::ser::{Serialize, Serializer};
use serde_hex::{encode, PrefixedHexVisitor};
use ssz::{Decode, Encode};
use std::cmp;
use std::default;
use std::marker::PhantomData;
use typenum::Unsigned;
/// Provides a common `impl` for structs that wrap a `$name`.
macro_rules! common_impl {
($name: ident) => {
impl<N: Unsigned> $name<N> {
/// Create a new BitList list with `initial_len` bits all set to `false`.
pub fn with_capacity(initial_len: usize) -> Result<Self, Error> {
Self::from_elem(initial_len, false)
}
/// Create a new bitfield with the given length `initial_len` and all values set to `bit`.
///
/// Note: if `initial_len` is not a multiple of 8, the remaining bits will be set to `false`
/// regardless of `bit`.
pub fn from_elem(initial_len: usize, bit: bool) -> Result<Self, Error> {
// BitVec can panic if we don't set the len to be a multiple of 8.
let full_len = ((initial_len + 7) / 8) * 8;
Self::validate_length(full_len)?;
let mut bitfield = Bitfield::from_elem(full_len, false);
if bit {
for i in 0..initial_len {
bitfield.set(i, true);
}
}
Ok(Self {
bitfield,
_phantom: PhantomData,
})
}
/// Create a new bitfield using the supplied `bytes` as input
pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
Self::validate_length(bytes.len().saturating_mul(8))?;
Ok(Self {
bitfield: Bitfield::from_bytes(&reverse_bit_order(bytes.to_vec())),
_phantom: PhantomData,
})
}
/// Returns a vector of bytes representing the bitfield
pub fn to_bytes(&self) -> Vec<u8> {
reverse_bit_order(self.bitfield.to_bytes().to_vec())
}
/// Read the value of a bit.
///
/// If the index is in bounds, then result is Ok(value) where value is `true` if the
/// bit is 1 and `false` if the bit is 0. If the index is out of bounds, we return an
/// error to that extent.
pub fn get(&self, i: usize) -> Result<bool, Error> {
if i < N::to_usize() {
match self.bitfield.get(i) {
Some(value) => Ok(value),
None => Err(Error::OutOfBounds {
i,
len: self.bitfield.len(),
}),
}
} else {
Err(Error::InvalidLength {
i,
len: N::to_usize(),
})
}
}
/// Set the value of a bit.
///
/// If the index is out of bounds, we expand the size of the underlying set to include
/// the new index. Returns the previous value if there was one.
pub fn set(&mut self, i: usize, value: bool) -> Result<(), Error> {
match self.get(i) {
Ok(previous) => Some(previous),
Err(Error::OutOfBounds { len, .. }) => {
let new_len = i - len + 1;
self.bitfield.grow(new_len, false);
None
}
Err(e) => return Err(e),
};
self.bitfield.set(i, value);
Ok(())
}
/// Returns the number of bits in this bitfield.
pub fn len(&self) -> usize {
self.bitfield.len()
}
/// Returns true if `self.len() == 0`
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Returns true if all bits are set to 0.
pub fn is_zero(&self) -> bool {
self.bitfield.none()
}
/// Returns the number of bytes required to represent this bitfield.
pub fn num_bytes(&self) -> usize {
self.to_bytes().len()
}
/// Returns the number of `1` bits in the bitfield
pub fn num_set_bits(&self) -> usize {
self.bitfield.iter().filter(|&bit| bit).count()
}
}
impl<N: Unsigned> cmp::PartialEq for $name<N> {
/// Determines equality by comparing the `ssz` encoding of the two candidates. This
/// method ensures that the presence of high-order (empty) bits in the highest byte do
/// not exclude equality when they are in fact representing the same information.
fn eq(&self, other: &Self) -> bool {
ssz::ssz_encode(self) == ssz::ssz_encode(other)
}
}
/// Create a new bitfield that is a union of two other bitfields.
///
/// For example `union(0101, 1000) == 1101`
// TODO: length-independent intersection for BitAnd
impl<N: Unsigned + Clone> std::ops::BitOr for $name<N> {
type Output = Self;
fn bitor(self, other: Self) -> Self {
let (biggest, smallest) = if self.len() > other.len() {
(&self, &other)
} else {
(&other, &self)
};
let mut new = (*biggest).clone();
for i in 0..smallest.len() {
if let Ok(true) = smallest.get(i) {
new.set(i, true)
.expect("Cannot produce bitfield larger than smallest of two given");
}
}
new
}
}
impl<N: Unsigned> Encode for $name<N> {
fn is_ssz_fixed_len() -> bool {
false
}
fn ssz_append(&self, buf: &mut Vec<u8>) {
buf.append(&mut self.to_bytes())
}
}
impl<N: Unsigned> Decode for $name<N> {
fn is_ssz_fixed_len() -> bool {
false
}
fn from_ssz_bytes(bytes: &[u8]) -> Result<Self, ssz::DecodeError> {
$name::from_bytes(bytes)
.map_err(|e| ssz::DecodeError::BytesInvalid(format!("Bitlist {:?}", e)))
}
}
impl<N: Unsigned> Serialize for $name<N> {
/// Serde serialization is compliant with the Ethereum YAML test format.
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serializer.serialize_str(&encode(self.to_bytes()))
}
}
impl<'de, N: Unsigned> Deserialize<'de> for $name<N> {
/// Serde serialization is compliant with the Ethereum YAML test format.
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
// We reverse the bit-order so that the BitVec library can read its 0th
// bit from the end of the hex string, e.g.
// "0xef01" => [0xef, 0x01] => [0b1000_0000, 0b1111_1110]
let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
$name::from_bytes(&bytes)
.map_err(|e| serde::de::Error::custom(format!("Bitlist {:?}", e)))
}
}
impl<N: Unsigned> tree_hash::TreeHash for $name<N> {
fn tree_hash_type() -> tree_hash::TreeHashType {
tree_hash::TreeHashType::List
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
unreachable!("List should never be packed.")
}
fn tree_hash_packing_factor() -> usize {
unreachable!("List should never be packed.")
}
fn tree_hash_root(&self) -> Vec<u8> {
self.to_bytes().tree_hash_root()
}
}
};
}
// Reverse the bit order of a whole byte vec, so that the ith bit
// of the input vec is placed in the (N - i)th bit of the output vec.
// This function is necessary for converting bitfields to and from YAML,
// as the BitVec library and the hex-parser use opposing bit orders.
fn reverse_bit_order(mut bytes: Vec<u8>) -> Vec<u8> {
bytes.reverse();
bytes.into_iter().map(LookupReverse::swap_bits).collect()
}
/// Emulates a SSZ `Bitvector`.
///
/// An ordered, heap-allocated, fixed-length, collection of `bool` values, with `N` values.
///
/// ## Notes
///
/// Considering this struct is backed by bytes, errors may be raised when attempting to decode
/// bytes into a `BitVector<N>` where `N` is not a multiple of 8. It is advised to always set `N` to
/// a multiple of 8.
///
/// ## Example
/// ```
/// use ssz_types::{BitVector, typenum};
///
/// let mut bitvec: BitVector<typenum::U8> = BitVector::new();
///
/// assert_eq!(bitvec.len(), 8);
///
/// for i in 0..8 {
/// assert_eq!(bitvec.get(i).unwrap(), false); // Defaults to false.
/// }
///
/// assert!(bitvec.get(8).is_err()); // Cannot get out-of-bounds.
///
/// assert!(bitvec.set(7, true).is_ok());
/// assert!(bitvec.set(8, true).is_err()); // Cannot set out-of-bounds.
/// ```
#[derive(Debug, Clone)]
pub struct BitVector<N> {
bitfield: Bitfield,
_phantom: PhantomData<N>,
}
common_impl!(BitVector);
impl<N: Unsigned> BitVector<N> {
/// Create a new bitfield.
pub fn new() -> Self {
Self::with_capacity(Self::capacity()).expect("Capacity must be correct")
}
fn capacity() -> usize {
N::to_usize()
}
fn validate_length(len: usize) -> Result<(), Error> {
let fixed_len = N::to_usize();
if len > fixed_len {
Err(Error::InvalidLength {
i: len,
len: fixed_len,
})
} else {
Ok(())
}
}
}
/// Emulates a SSZ `Bitlist`.
///
/// An ordered, heap-allocated, variable-length, collection of `bool` values, limited to `N`
/// values.
///
/// ## Notes
///
/// Considering this struct is backed by bytes, errors may be raised when attempting to decode
/// bytes into a `BitList<N>` where `N` is not a multiple of 8. It is advised to always set `N` to
/// a multiple of 8.
///
/// ## Example
/// ```
/// use ssz_types::{BitList, typenum};
///
/// let mut bitlist: BitList<typenum::U8> = BitList::new();
///
/// assert_eq!(bitlist.len(), 0);
///
/// assert!(bitlist.get(0).is_err()); // Cannot get at or below the length.
///
/// for i in 0..8 {
/// assert!(bitlist.set(i, true).is_ok());
/// }
///
/// assert!(bitlist.set(8, true).is_err()); // Cannot set out-of-bounds.
///
/// // Cannot create with an excessive capacity.
/// let result: Result<BitList<typenum::U8>, _> = BitList::with_capacity(9);
/// assert!(result.is_err());
/// ```
#[derive(Debug, Clone)]
pub struct BitList<N> {
bitfield: Bitfield,
_phantom: PhantomData<N>,
}
common_impl!(BitList);
impl<N: Unsigned> BitList<N> {
/// Create a new, empty BitList.
pub fn new() -> Self {
Self {
bitfield: Bitfield::default(),
_phantom: PhantomData,
}
}
fn validate_length(len: usize) -> Result<(), Error> {
let max_len = Self::max_len();
if len > max_len {
Err(Error::InvalidLength {
i: len,
len: max_len,
})
} else {
Ok(())
}
}
/// The maximum possible number of bits.
pub fn max_len() -> usize {
N::to_usize()
}
}
impl<N: Unsigned + Clone> BitList<N> {
/// Compute the intersection (binary-and) of this bitfield with another
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn intersection(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res: Self = self.to_owned();
res.intersection_inplace(other);
res
}
/// Like `intersection` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn intersection_inplace(&mut self, other: &Self) {
self.bitfield.intersect(&other.bitfield);
}
/// Compute the union (binary-or) of this bitfield with another. Lengths must match.
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn union(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res = self.clone();
res.union_inplace(other);
res
}
/// Like `union` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn union_inplace(&mut self, other: &Self) {
self.bitfield.union(&other.bitfield);
}
/// Compute the difference (binary-minus) of this bitfield with another. Lengths must match.
///
/// Computes `self - other`.
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn difference(&self, other: &Self) -> Self {
assert_eq!(self.len(), other.len());
let mut res = self.clone();
res.difference_inplace(other);
res
}
/// Like `difference` but in-place (updates `self`).
///
/// ## Panics
///
/// If `self` and `other` have different lengths.
pub fn difference_inplace(&mut self, other: &Self) {
self.bitfield.difference(&other.bitfield);
}
}
impl<N: Unsigned> default::Default for BitList<N> {
/// Default provides the "empty" bitfield
/// Note: the empty bitfield is set to the `0` byte.
fn default() -> Self {
Self::from_elem(0, false).expect("Zero cannot be larger than the maximum length")
}
}
/*
#[cfg(test)]
mod tests {
use super::*;
use serde_yaml;
use ssz::ssz_encode;
use tree_hash::TreeHash;
impl Bitfield {
/// Create a new bitfield.
pub fn new() -> Self {
Default::default()
}
}
#[test]
pub fn test_cached_tree_hash() {
let original = Bitfield::from_bytes(&vec![18; 12][..]);
let mut cache = cached_tree_hash::TreeHashCache::new(&original).unwrap();
assert_eq!(
cache.tree_hash_root().unwrap().to_vec(),
original.tree_hash_root()
);
let modified = Bitfield::from_bytes(&vec![2; 1][..]);
cache.update(&modified).unwrap();
assert_eq!(
cache.tree_hash_root().unwrap().to_vec(),
modified.tree_hash_root()
);
}
#[test]
fn test_new_bitfield() {
let mut field = Bitfield::new();
let original_len = field.len();
for i in 0..100 {
if i < original_len {
assert!(!field.get(i).unwrap());
} else {
assert!(field.get(i).is_err());
}
let previous = field.set(i, true);
if i < original_len {
assert!(!previous.unwrap());
} else {
assert!(previous.is_none());
}
}
}
#[test]
fn test_empty_bitfield() {
let mut field = Bitfield::from_elem(0, false);
let original_len = field.len();
assert_eq!(original_len, 0);
for i in 0..100 {
if i < original_len {
assert!(!field.get(i).unwrap());
} else {
assert!(field.get(i).is_err());
}
let previous = field.set(i, true);
if i < original_len {
assert!(!previous.unwrap());
} else {
assert!(previous.is_none());
}
}
assert_eq!(field.len(), 100);
assert_eq!(field.num_set_bits(), 100);
}
const INPUT: &[u8] = &[0b0100_0000, 0b0100_0000];
#[test]
fn test_get_from_bitfield() {
let field = Bitfield::from_bytes(INPUT);
let unset = field.get(0).unwrap();
assert!(!unset);
let set = field.get(6).unwrap();
assert!(set);
let set = field.get(14).unwrap();
assert!(set);
}
#[test]
fn test_set_for_bitfield() {
let mut field = Bitfield::from_bytes(INPUT);
let previous = field.set(10, true).unwrap();
assert!(!previous);
let previous = field.get(10).unwrap();
assert!(previous);
let previous = field.set(6, false).unwrap();
assert!(previous);
let previous = field.get(6).unwrap();
assert!(!previous);
}
#[test]
fn test_len() {
let field = Bitfield::from_bytes(INPUT);
assert_eq!(field.len(), 16);
let field = Bitfield::new();
assert_eq!(field.len(), 8);
}
#[test]
fn test_num_set_bits() {
let field = Bitfield::from_bytes(INPUT);
assert_eq!(field.num_set_bits(), 2);
let field = Bitfield::new();
assert_eq!(field.num_set_bits(), 0);
}
#[test]
fn test_to_bytes() {
let field = Bitfield::from_bytes(INPUT);
assert_eq!(field.to_bytes(), INPUT);
let field = Bitfield::new();
assert_eq!(field.to_bytes(), vec![0]);
}
#[test]
fn test_out_of_bounds() {
let mut field = Bitfield::from_bytes(INPUT);
let out_of_bounds_index = field.len();
assert!(field.set(out_of_bounds_index, true).is_none());
assert!(field.len() == out_of_bounds_index + 1);
assert!(field.get(out_of_bounds_index).unwrap());
for i in 0..100 {
if i <= out_of_bounds_index {
assert!(field.set(i, true).is_some());
} else {
assert!(field.set(i, true).is_none());
}
}
}
#[test]
fn test_grows_with_false() {
let input_all_set: &[u8] = &[0b1111_1111, 0b1111_1111];
let mut field = Bitfield::from_bytes(input_all_set);
// Define `a` and `b`, where both are out of bounds and `b` is greater than `a`.
let a = field.len();
let b = a + 1;
// Ensure `a` is out-of-bounds for test integrity.
assert!(field.get(a).is_err());
// Set `b` to `true`. Also, for test integrity, ensure it was previously out-of-bounds.
assert!(field.set(b, true).is_none());
// Ensure that `a` wasn't also set to `true` during the grow.
assert_eq!(field.get(a), Ok(false));
assert_eq!(field.get(b), Ok(true));
}
#[test]
fn test_num_bytes() {
let field = Bitfield::from_bytes(INPUT);
assert_eq!(field.num_bytes(), 2);
let field = Bitfield::from_elem(2, true);
assert_eq!(field.num_bytes(), 1);
let field = Bitfield::from_elem(13, true);
assert_eq!(field.num_bytes(), 2);
}
#[test]
fn test_ssz_encode() {
let field = create_test_bitfield();
assert_eq!(field.as_ssz_bytes(), vec![0b0000_0011, 0b1000_0111]);
let field = Bitfield::from_elem(18, true);
assert_eq!(
field.as_ssz_bytes(),
vec![0b0000_0011, 0b1111_1111, 0b1111_1111]
);
let mut b = Bitfield::new();
b.set(1, true);
assert_eq!(ssz_encode(&b), vec![0b0000_0010]);
}
fn create_test_bitfield() -> Bitfield {
let count = 2 * 8;
let mut field = Bitfield::with_capacity(count);
let indices = &[0, 1, 2, 7, 8, 9];
for &i in indices {
field.set(i, true);
}
field
}
#[test]
fn test_ssz_decode() {
let encoded = vec![0b0000_0011, 0b1000_0111];
let field = Bitfield::from_ssz_bytes(&encoded).unwrap();
let expected = create_test_bitfield();
assert_eq!(field, expected);
let encoded = vec![255, 255, 3];
let field = Bitfield::from_ssz_bytes(&encoded).unwrap();
let expected = Bitfield::from_bytes(&[255, 255, 3]);
assert_eq!(field, expected);
}
#[test]
fn test_serialize_deserialize() {
use serde_yaml::Value;
let data: &[(_, &[_])] = &[
("0x01", &[0b00000001]),
("0xf301", &[0b11110011, 0b00000001]),
];
for (hex_data, bytes) in data {
let bitfield = Bitfield::from_bytes(bytes);
assert_eq!(
serde_yaml::from_str::<Bitfield>(hex_data).unwrap(),
bitfield
);
assert_eq!(
serde_yaml::to_value(&bitfield).unwrap(),
Value::String(hex_data.to_string())
);
}
}
#[test]
fn test_ssz_round_trip() {
let original = Bitfield::from_bytes(&vec![18; 12][..]);
let ssz = ssz_encode(&original);
let decoded = Bitfield::from_ssz_bytes(&ssz).unwrap();
assert_eq!(original, decoded);
}
#[test]
fn test_bitor() {
let a = Bitfield::from_bytes(&vec![2, 8, 1][..]);
let b = Bitfield::from_bytes(&vec![4, 8, 16][..]);
let c = Bitfield::from_bytes(&vec![6, 8, 17][..]);
assert_eq!(c, a | b);
}
#[test]
fn test_is_zero() {
let yes_data: &[&[u8]] = &[&[], &[0], &[0, 0], &[0, 0, 0]];
for bytes in yes_data {
assert!(Bitfield::from_bytes(bytes).is_zero());
}
let no_data: &[&[u8]] = &[&[1], &[6], &[0, 1], &[0, 0, 1], &[0, 0, 255]];
for bytes in no_data {
assert!(!Bitfield::from_bytes(bytes).is_zero());
}
}
#[test]
fn test_intersection() {
let a = Bitfield::from_bytes(&[0b1100, 0b0001]);
let b = Bitfield::from_bytes(&[0b1011, 0b1001]);
let c = Bitfield::from_bytes(&[0b1000, 0b0001]);
assert_eq!(a.intersection(&b), c);
assert_eq!(b.intersection(&a), c);
assert_eq!(a.intersection(&c), c);
assert_eq!(b.intersection(&c), c);
assert_eq!(a.intersection(&a), a);
assert_eq!(b.intersection(&b), b);
assert_eq!(c.intersection(&c), c);
}
#[test]
fn test_union() {
let a = Bitfield::from_bytes(&[0b1100, 0b0001]);
let b = Bitfield::from_bytes(&[0b1011, 0b1001]);
let c = Bitfield::from_bytes(&[0b1111, 0b1001]);
assert_eq!(a.union(&b), c);
assert_eq!(b.union(&a), c);
assert_eq!(a.union(&a), a);
assert_eq!(b.union(&b), b);
assert_eq!(c.union(&c), c);
}
#[test]
fn test_difference() {
let a = Bitfield::from_bytes(&[0b1100, 0b0001]);
let b = Bitfield::from_bytes(&[0b1011, 0b1001]);
let a_b = Bitfield::from_bytes(&[0b0100, 0b0000]);
let b_a = Bitfield::from_bytes(&[0b0011, 0b1000]);
assert_eq!(a.difference(&b), a_b);
assert_eq!(b.difference(&a), b_a);
assert!(a.difference(&a).is_zero());
}
}
*/

229
eth2/utils/ssz_types/src/impl_bitfield_fns.rs Normal file
View File

@ -0,0 +1,229 @@
use bit_reverse::LookupReverse;
/// Provides a common `impl` for structs that wrap a `$name`.
#[macro_export]
macro_rules! impl_bitfield_fns {
($name: ident) => {
impl<N: Unsigned> $name<N> {
/// Create a new BitList list with `initial_len` bits all set to `false`.
pub fn with_capacity(initial_len: usize) -> Result<Self, Error> {
Self::from_elem(initial_len, false)
}
/// Create a new bitfield with the given length `initial_len` and all values set to `bit`.
///
/// Note: if `initial_len` is not a multiple of 8, the remaining bits will be set to `false`
/// regardless of `bit`.
pub fn from_elem(initial_len: usize, bit: bool) -> Result<Self, Error> {
// BitVec can panic if we don't set the len to be a multiple of 8.
let full_len = ((initial_len + 7) / 8) * 8;
Self::validate_length(full_len)?;
let mut bitfield = Bitfield::from_elem(full_len, false);
if bit {
for i in 0..initial_len {
bitfield.set(i, true);
}
}
Ok(Self {
bitfield,
_phantom: PhantomData,
})
}
/// Create a new bitfield using the supplied `bytes` as input
pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
Self::validate_length(bytes.len().saturating_mul(8))?;
Ok(Self {
bitfield: Bitfield::from_bytes(&reverse_bit_order(bytes.to_vec())),
_phantom: PhantomData,
})
}
/// Returns a vector of bytes representing the bitfield
pub fn to_bytes(&self) -> Vec<u8> {
if self.bitfield.is_empty() {
vec![0] // Empty bitfield should be represented as a zero byte.
} else {
reverse_bit_order(self.bitfield.to_bytes().to_vec())
}
}
/// Read the value of a bit.
///
/// If the index is in bounds, then result is Ok(value) where value is `true` if the
/// bit is 1 and `false` if the bit is 0. If the index is out of bounds, we return an
/// error to that extent.
pub fn get(&self, i: usize) -> Result<bool, Error> {
if i < N::to_usize() {
match self.bitfield.get(i) {
Some(value) => Ok(value),
None => Err(Error::OutOfBounds {
i,
len: self.bitfield.len(),
}),
}
} else {
Err(Error::InvalidLength {
i,
len: N::to_usize(),
})
}
}
/// Set the value of a bit.
///
/// If the index is out of bounds, we expand the size of the underlying set to include
/// the new index. Returns the previous value if there was one.
pub fn set(&mut self, i: usize, value: bool) -> Result<(), Error> {
match self.get(i) {
Ok(previous) => Some(previous),
Err(Error::OutOfBounds { len, .. }) => {
let new_len = i - len + 1;
self.bitfield.grow(new_len, false);
None
}
Err(e) => return Err(e),
};
self.bitfield.set(i, value);
Ok(())
}
/// Returns the number of bits in this bitfield.
pub fn len(&self) -> usize {
self.bitfield.len()
}
/// Returns true if `self.len() == 0`
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Returns true if all bits are set to 0.
pub fn is_zero(&self) -> bool {
self.bitfield.none()
}
/// Returns the number of bytes required to represent this bitfield.
pub fn num_bytes(&self) -> usize {
self.to_bytes().len()
}
/// Returns the number of `1` bits in the bitfield
pub fn num_set_bits(&self) -> usize {
self.bitfield.iter().filter(|&bit| bit).count()
}
}
impl<N: Unsigned> cmp::PartialEq for $name<N> {
/// Determines equality by comparing the `ssz` encoding of the two candidates. This
/// method ensures that the presence of high-order (empty) bits in the highest byte do
/// not exclude equality when they are in fact representing the same information.
fn eq(&self, other: &Self) -> bool {
ssz::ssz_encode(self) == ssz::ssz_encode(other)
}
}
/// Create a new bitfield that is a union of two other bitfields.
///
/// For example `union(0101, 1000) == 1101`
// TODO: length-independent intersection for BitAnd
impl<N: Unsigned + Clone> std::ops::BitOr for $name<N> {
type Output = Self;
fn bitor(self, other: Self) -> Self {
let (biggest, smallest) = if self.len() > other.len() {
(&self, &other)
} else {
(&other, &self)
};
let mut new = (*biggest).clone();
for i in 0..smallest.len() {
if let Ok(true) = smallest.get(i) {
new.set(i, true)
.expect("Cannot produce bitfield larger than smallest of two given");
}
}
new
}
}
impl<N: Unsigned> Encode for $name<N> {
fn is_ssz_fixed_len() -> bool {
false
}
fn ssz_append(&self, buf: &mut Vec<u8>) {
buf.append(&mut self.to_bytes())
}
}
impl<N: Unsigned> Decode for $name<N> {
fn is_ssz_fixed_len() -> bool {
false
}
fn from_ssz_bytes(bytes: &[u8]) -> Result<Self, ssz::DecodeError> {
$name::from_bytes(bytes)
.map_err(|e| ssz::DecodeError::BytesInvalid(format!("Bitfield {:?}", e)))
}
}
impl<N: Unsigned> Serialize for $name<N> {
/// Serde serialization is compliant with the Ethereum YAML test format.
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serializer.serialize_str(&encode(self.to_bytes()))
}
}
impl<'de, N: Unsigned> Deserialize<'de> for $name<N> {
/// Serde serialization is compliant with the Ethereum YAML test format.
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
// We reverse the bit-order so that the BitVec library can read its 0th
// bit from the end of the hex string, e.g.
// "0xef01" => [0xef, 0x01] => [0b1000_0000, 0b1111_1110]
let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
$name::from_bytes(&bytes)
.map_err(|e| serde::de::Error::custom(format!("Bitfield {:?}", e)))
}
}
impl<N: Unsigned> tree_hash::TreeHash for $name<N> {
fn tree_hash_type() -> tree_hash::TreeHashType {
tree_hash::TreeHashType::List
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
unreachable!("List should never be packed.")
}
fn tree_hash_packing_factor() -> usize {
unreachable!("List should never be packed.")
}
fn tree_hash_root(&self) -> Vec<u8> {
self.to_bytes().tree_hash_root()
}
}
};
}
// Reverse the bit order of a whole byte vec, so that the ith bit
// of the input vec is placed in the (N - i)th bit of the output vec.
// This function is necessary for converting bitfields to and from YAML,
// as the BitVec library and the hex-parser use opposing bit orders.
pub fn reverse_bit_order(mut bytes: Vec<u8>) -> Vec<u8> {
bytes.reverse();
bytes.into_iter().map(LookupReverse::swap_bits).collect()
}

10
eth2/utils/ssz_types/src/lib.rs
View File

@ -1,8 +1,14 @@
mod bitfield;
#[macro_use]
mod impl_bitfield_fns;
mod bit_list;
mod bit_vector;
mod fixed_vector;
mod variable_list;
pub use bitfield::{BitList, BitVector};
use impl_bitfield_fns::reverse_bit_order;
pub use bit_list::BitList;
pub use bit_vector::BitVector;
pub use fixed_vector::FixedVector;
pub use typenum;
pub use variable_list::VariableList;