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Merged
nlordell merged 1 commit into from
Sep 15, 2022
Merged

Add optional binary serialization #20

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288 changes: 288 additions & 0 deletions src/serde.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -297,6 +297,88 @@ pub mod permissive {
}
}

/// Module for use with `#[serde(with = "ethnum::serde::binary")]` to
/// specify little endian binary serialization for 256-bit integer types.
pub mod binary {
use crate::{I256, U256};
use core::convert::TryInto;
use core::fmt::{self, Formatter};
use core::marker::PhantomData;
use serde::{
de::{self, Deserializer, Visitor},
Serializer,
};

#[doc(hidden)]
pub trait Binary: Sized + Copy {
fn to_bytes(self) -> [u8; 32];
fn from_bytes(bytes: [u8; 32]) -> Self;
}

impl Binary for I256 {
fn to_bytes(self) -> [u8; 32] {
self.to_le_bytes()
}

fn from_bytes(bytes: [u8; 32]) -> Self {
I256::from_le_bytes(bytes)
}
}

impl Binary for U256 {
fn to_bytes(self) -> [u8; 32] {
self.to_le_bytes()
}

fn from_bytes(bytes: [u8; 32]) -> Self {
U256::from_le_bytes(bytes)
}
}

#[doc(hidden)]
pub fn serialize<T, S>(value: &T, serializer: S) -> Result<S::Ok, S::Error>
where
T: Binary,
S: Serializer,
{
let bytes = value.to_bytes();
serializer.serialize_bytes(&bytes)
}

struct BinaryVisitor<T>(PhantomData<T>);

impl<'de, T> Visitor<'de> for BinaryVisitor<T>
where
T: Binary,
{
type Value = T;

fn expecting(&self, f: &mut Formatter) -> fmt::Result {
f.write_str("32 bytes in little endian")
}

fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
where
E: de::Error,
{
let bytes = v
.try_into()
.map_err(|_| E::invalid_length(v.len(), &self))?;

Ok(T::from_bytes(bytes))
}
}

#[doc(hidden)]
pub fn deserialize<'de, T, D>(deserializer: D) -> Result<T, D::Error>
where
T: Binary,
D: Deserializer<'de>,
{
deserializer.deserialize_bytes(BinaryVisitor(PhantomData))
}
}

/// Internal visitor struct implementation to facilitate implementing different
/// serialization formats.
struct FormatVisitor<F>(F);
Expand Down Expand Up @@ -406,6 +488,8 @@ mod tests {
fmt::{Display, LowerHex},
format,
string::String,
vec,
vec::Vec,
};
use serde::{
de::{value, IntoDeserializer},
Expand All @@ -421,6 +505,13 @@ mod tests {
}};
}

macro_rules! bin_ser {
($method:expr, $value:expr) => {{
let value = $value;
($method)(&value, BytesSerializer).unwrap()
}};
}

assert_eq!(
ser!(I256::serialize, I256::MIN),
"-0x8000000000000000000000000000000000000000000000000000000000000000",
Expand Down Expand Up @@ -453,6 +544,24 @@ mod tests {

assert_eq!(ser!(prefixed::serialize, I256::new(42)), "0x2a");
assert_eq!(ser!(permissive::serialize, I256::new(42)), "0x2a");

assert_eq!(bin_ser!(binary::serialize, U256::ZERO), vec![0_u8; 32]);
assert_eq!(bin_ser!(binary::serialize, U256::MAX), vec![0xFF_u8; 32]);
assert_eq!(bin_ser!(binary::serialize, U256::new(0x4215)), {
let mut v = vec![0x15, 0x42];
v.resize(32, 0);
v
});

assert_eq!(
bin_ser!(binary::serialize, I256::new(-1)),
vec![0xFF_u8; 32]
);
assert_eq!(bin_ser!(binary::serialize, I256::new(-424242)), {
let mut v = vec![0xCE, 0x86, 0xF9];
v.resize(32, 0xFF);
v
});
}

#[test]
Expand Down Expand Up @@ -625,6 +734,36 @@ mod tests {
assert!(
de!(err; permissive::deserialize::<U256, _>, "0x10000000000000000000000000000000000000000000000000000000000000000")
);

assert_eq!(
de!(binary::deserialize::<U256, _>, [0; 32].as_slice()),
U256::ZERO
);

assert_eq!(
de!(binary::deserialize::<U256, _>, [0xFF; 32].as_slice()),
U256::MAX
);

let forty_two = {
let mut v = vec![42];
v.resize(32, 0);
v
};
assert_eq!(
de!(binary::deserialize::<U256, _>, forty_two.as_slice()),
U256::new(42)
);

assert_eq!(
de!(binary::deserialize::<I256, _>, [0; 32].as_slice()),
I256::ZERO
);

assert_eq!(
de!(binary::deserialize::<I256, _>, [0xFF; 32].as_slice()),
I256::new(-1)
);
}

#[test]
Expand Down Expand Up @@ -801,4 +940,153 @@ mod tests {
todo!()
}
}

/// A string serializer used for testing.
struct BytesSerializer;

impl Serializer for BytesSerializer {
type Ok = Vec<u8>;
type Error = fmt::Error;
type SerializeSeq = Impossible<Vec<u8>, fmt::Error>;
type SerializeTuple = Impossible<Vec<u8>, fmt::Error>;
type SerializeTupleStruct = Impossible<Vec<u8>, fmt::Error>;
type SerializeTupleVariant = Impossible<Vec<u8>, fmt::Error>;
type SerializeMap = Impossible<Vec<u8>, fmt::Error>;
type SerializeStruct = Impossible<Vec<u8>, fmt::Error>;
type SerializeStructVariant = Impossible<Vec<u8>, fmt::Error>;
fn serialize_bool(self, _: bool) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_i8(self, _: i8) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_i16(self, _: i16) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_i32(self, _: i32) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_i64(self, _: i64) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_u8(self, _: u8) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_u16(self, _: u16) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_u32(self, _: u32) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_u64(self, _: u64) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_f32(self, _: f32) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_f64(self, _: f64) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_char(self, _: char) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_str(self, _: &str) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
Ok(v.to_vec())
}
fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_some<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
where
T: Serialize,
{
unimplemented!()
}
fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_unit_struct(self, _: &'static str) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_unit_variant(
self,
_: &'static str,
_: u32,
_: &'static str,
) -> Result<Self::Ok, Self::Error> {
unimplemented!()
}
fn serialize_newtype_struct<T: ?Sized>(
self,
_: &'static str,
_: &T,
) -> Result<Self::Ok, Self::Error>
where
T: Serialize,
{
unimplemented!()
}
fn serialize_newtype_variant<T: ?Sized>(
self,
_: &'static str,
_: u32,
_: &'static str,
_: &T,
) -> Result<Self::Ok, Self::Error>
where
T: Serialize,
{
unimplemented!()
}
fn serialize_seq(self, _: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
unimplemented!()
}
fn serialize_tuple(self, _: usize) -> Result<Self::SerializeTuple, Self::Error> {
unimplemented!()
}
fn serialize_tuple_struct(
self,
_: &'static str,
_: usize,
) -> Result<Self::SerializeTupleStruct, Self::Error> {
unimplemented!()
}
fn serialize_tuple_variant(
self,
_: &'static str,
_: u32,
_: &'static str,
_: usize,
) -> Result<Self::SerializeTupleVariant, Self::Error> {
unimplemented!()
}
fn serialize_map(self, _: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
unimplemented!()
}
fn serialize_struct(
self,
_: &'static str,
_: usize,
) -> Result<Self::SerializeStruct, Self::Error> {
unimplemented!()
}
fn serialize_struct_variant(
self,
_: &'static str,
_: u32,
_: &'static str,
_: usize,
) -> Result<Self::SerializeStructVariant, Self::Error> {
unimplemented!()
}
fn collect_str<T>(self, _: &T) -> Result<Self::Ok, Self::Error>
where
T: Display + ?Sized,
{
todo!()
}
}
}