Implement Num from num-traits (#480)

ethereum-types/Cargo.toml

@@ -26,3 +26,4 @@ serialize = ["std", "impl-serde", "primitive-types/serde", "ethbloom/serialize"]
 arbitrary = ["ethbloom/arbitrary", "fixed-hash/arbitrary", "uint-crate/arbitrary"]
 rlp = ["impl-rlp", "ethbloom/rlp", "primitive-types/rlp"]
 codec = ["impl-codec", "ethbloom/codec"]
+num-traits = ["primitive-types/num-traits"]

ethereum-types/src/lib.rs

@@ -13,6 +13,8 @@ mod uint;
 
 pub use ethbloom::{Bloom, BloomRef, Input as BloomInput};
 pub use hash::{BigEndianHash, H128, H160, H256, H264, H32, H512, H520, H64};
+#[cfg(feature = "num-traits")]
+pub use primitive_types::{FromStrRadixErr, FromStrRadixErrKind};
 pub use uint::{FromDecStrErr, U128, U256, U512, U64};
 
 pub type Address = H160;

primitive-types/Cargo.toml

@@ -12,6 +12,7 @@ fixed-hash = { version = "0.6", path = "../fixed-hash", default-features = false
 uint = { version = "0.8.3", path = "../uint", default-features = false }
 impl-serde = { version = "0.3.1", path = "impls/serde", default-features = false, optional = true }
 impl-codec = { version = "0.4.1", path = "impls/codec", default-features = false, optional = true }
+impl-num-traits = { version = "0.1.0", path = "impls/num-traits", default-features = false, optional = true }
 impl-rlp = { version = "0.3", path = "impls/rlp", default-features = false, optional = true }
 scale-info = { version = "0.4", features = ["derive"], default-features = false, optional = true }
 
@@ -26,6 +27,7 @@ codec = ["impl-codec"]
 rlp = ["impl-rlp"]
 arbitrary = ["fixed-hash/arbitrary", "uint/arbitrary"]
 fp-conversion = ["std"]
+num-traits = ["impl-num-traits"]
 
 [[test]]
 name = "scale_info"

primitive-types/impls/num-traits/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "impl-num-traits"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+license = "MIT OR Apache-2.0"
+homepage = "https://github.com/paritytech/parity-common"
+description = "num-traits implementation for uint."
+edition = "2018"
+
+[dependencies]
+num-traits = { version = "0.2", default-features = false }
+uint = { version = "0.8.5", path = "../../../uint", default-features = false }
+
+[features]
+default = ["std"]
+std = ["num-traits/std", "uint/std"]

primitive-types/impls/num-traits/src/lib.rs

@@ -0,0 +1,49 @@
+// Copyright 2020 Parity Technologies
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! num-traits support for uint.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[doc(hidden)]
+pub use num_traits;
+
+pub use uint::{FromStrRadixErr, FromStrRadixErrKind};
+
+/// Add num-traits support to an integer created by `construct_uint!`.
+#[macro_export]
+macro_rules! impl_uint_num_traits {
+	($name: ident, $len: expr) => {
+		impl $crate::num_traits::identities::Zero for $name {
+			#[inline]
+			fn zero() -> Self {
+				Self::zero()
+			}
+
+			#[inline]
+			fn is_zero(&self) -> bool {
+				self.is_zero()
+			}
+		}
+
+		impl $crate::num_traits::identities::One for $name {
+			#[inline]
+			fn one() -> Self {
+				Self::one()
+			}
+		}
+
+		impl $crate::num_traits::Num for $name {
+			type FromStrRadixErr = $crate::FromStrRadixErr;
+
+			fn from_str_radix(txt: &str, radix: u32) -> Result<Self, Self::FromStrRadixErr> {
+				Self::from_str_radix(txt, radix)
+			}
+		}
+	};
+}

primitive-types/src/lib.rs

@@ -22,6 +22,7 @@ use fixed_hash::{construct_fixed_hash, impl_fixed_hash_conversions};
 #[cfg(feature = "scale-info")]
 use scale_info::TypeInfo;
 use uint::{construct_uint, uint_full_mul_reg};
+pub use uint::{FromStrRadixErr, FromStrRadixErrKind};
 
 /// Error type for conversion.
 #[derive(Debug, PartialEq, Eq)]
@@ -68,6 +69,16 @@ construct_fixed_hash! {
 	pub struct H512(64);
 }
 
+#[cfg(feature = "num-traits")]
+mod num_traits {
+	use super::*;
+	use impl_num_traits::impl_uint_num_traits;
+
+	impl_uint_num_traits!(U128, 2);
+	impl_uint_num_traits!(U256, 4);
+	impl_uint_num_traits!(U512, 8);
+}
+
 #[cfg(feature = "impl-serde")]
 mod serde {
 	use super::*;

uint/src/uint.rs

@@ -31,6 +31,102 @@
 
 use core::fmt;
 
+/// A list of error categories encountered when parsing numbers.
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
+#[non_exhaustive]
+pub enum FromStrRadixErrKind {
+	/// A character in the input string is not valid for the given radix.
+	InvalidCharacter,
+
+	/// The input length is not valid for the given radix.
+	InvalidLength,
+
+	/// The given radix is not supported.
+	UnsupportedRadix,
+}
+
+#[derive(Debug)]
+enum FromStrRadixErrSrc {
+	Hex(FromHexError),
+	Dec(FromDecStrErr),
+}
+
+impl fmt::Display for FromStrRadixErrSrc {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			FromStrRadixErrSrc::Dec(d) => write!(f, "{}", d),
+			FromStrRadixErrSrc::Hex(h) => write!(f, "{}", h),
+		}
+	}
+}
+
+/// The error type for parsing numbers from strings.
+#[derive(Debug)]
+pub struct FromStrRadixErr {
+	kind: FromStrRadixErrKind,
+	source: Option<FromStrRadixErrSrc>,
+}
+
+impl FromStrRadixErr {
+	#[doc(hidden)]
+	pub fn unsupported() -> Self {
+		Self { kind: FromStrRadixErrKind::UnsupportedRadix, source: None }
+	}
+
+	/// Returns the corresponding `FromStrRadixErrKind` for this error.
+	pub fn kind(&self) -> FromStrRadixErrKind {
+		self.kind
+	}
+}
+
+impl fmt::Display for FromStrRadixErr {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		if let Some(ref src) = self.source {
+			return write!(f, "{}", src);
+		}
+
+		match self.kind {
+			FromStrRadixErrKind::UnsupportedRadix => write!(f, "the given radix is not supported"),
+			FromStrRadixErrKind::InvalidCharacter => write!(f, "input contains an invalid character"),
+			FromStrRadixErrKind::InvalidLength => write!(f, "length not supported for radix or type"),
+		}
+	}
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for FromStrRadixErr {
+	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+		match self.source {
+			Some(FromStrRadixErrSrc::Dec(ref d)) => Some(d),
+			Some(FromStrRadixErrSrc::Hex(ref h)) => Some(h),
+			None => None,
+		}
+	}
+}
+
+impl From<FromDecStrErr> for FromStrRadixErr {
+	fn from(e: FromDecStrErr) -> Self {
+		let kind = match e {
+			FromDecStrErr::InvalidCharacter => FromStrRadixErrKind::InvalidCharacter,
+			FromDecStrErr::InvalidLength => FromStrRadixErrKind::InvalidLength,
+		};
+
+		Self { kind, source: Some(FromStrRadixErrSrc::Dec(e)) }
+	}
+}
+
+impl From<FromHexError> for FromStrRadixErr {
+	fn from(e: FromHexError) -> Self {
+		let kind = match e.inner {
+			hex::FromHexError::InvalidHexCharacter { .. } => FromStrRadixErrKind::InvalidCharacter,
+			hex::FromHexError::InvalidStringLength => FromStrRadixErrKind::InvalidLength,
+			hex::FromHexError::OddLength => FromStrRadixErrKind::InvalidLength,
+		};
+
+		Self { kind, source: Some(FromStrRadixErrSrc::Hex(e)) }
+	}
+}
+
 /// Conversion from decimal string error
 #[derive(Debug, PartialEq)]
 pub enum FromDecStrErr {
@@ -493,6 +589,18 @@ macro_rules! construct_uint {
 			/// Maximum value.
 			pub const MAX: $name = $name([u64::max_value(); $n_words]);
 
+			/// Converts a string slice in a given base to an integer. Only supports radixes of 10
+			/// and 16.
+			pub fn from_str_radix(txt: &str, radix: u32) -> Result<Self, $crate::FromStrRadixErr> {
+				let parsed = match radix {
+					10 => Self::from_dec_str(txt)?,
+					16 => core::str::FromStr::from_str(txt)?,
+					_ => return Err($crate::FromStrRadixErr::unsupported()),
+				};
+
+				Ok(parsed)
+			}
+
 			/// Convert from a decimal string.
 			pub fn from_dec_str(value: &str) -> $crate::core_::result::Result<Self, $crate::FromDecStrErr> {
 				if !value.bytes().all(|b| b >= 48 && b <= 57) {