Expose to_hex and from_hex from impl-serde

ethbloom/Cargo.toml

@@ -13,7 +13,7 @@ edition = "2018"
 tiny-keccak = { version = "2.0", features = ["keccak"] }
 crunchy = { version = "0.2.2", default-features = false, features = ["limit_256"] }
 fixed-hash = { path = "../fixed-hash", version = "0.5", default-features = false }
-impl-serde = { path = "../primitive-types/impls/serde", version = "0.2", default-features = false, optional = true }
+impl-serde = { path = "../primitive-types/impls/serde", version = "0.3", default-features = false, optional = true }
 impl-rlp = { path = "../primitive-types/impls/rlp", version = "0.2", default-features = false }
 
 [dev-dependencies]

ethereum-types/Cargo.toml

@@ -12,7 +12,7 @@ ethbloom = { path = "../ethbloom", version = "0.8", default-features = false }
 fixed-hash = { path = "../fixed-hash", version = "0.5", default-features = false, features = ["byteorder", "rustc-hex"] }
 uint-crate = { path = "../uint", package = "uint", version = "0.8", default-features = false }
 primitive-types = { path = "../primitive-types", version = "0.6", features = ["rlp", "byteorder", "rustc-hex"], default-features = false }
-impl-serde = { path = "../primitive-types/impls/serde", version = "0.2", default-features = false, optional = true }
+impl-serde = { path = "../primitive-types/impls/serde", version = "0.3.0", default-features = false, optional = true }
 impl-rlp = { path = "../primitive-types/impls/rlp", version = "0.2", default-features = false }
 
 [dev-dependencies]

primitive-types/Cargo.toml

@@ -10,7 +10,7 @@ edition = "2018"
 [dependencies]
 fixed-hash = { version = "0.5", path = "../fixed-hash", default-features = false }
 uint = { version = "0.8.1", path = "../uint", default-features = false }
-impl-serde = { version = "0.2.1", path = "impls/serde", default-features = false, optional = true }
+impl-serde = { version = "0.3.0", path = "impls/serde", default-features = false, optional = true }
 impl-codec = { version = "0.4.1", path = "impls/codec", default-features = false, optional = true }
 impl-rlp = { version = "0.2", path = "impls/rlp", default-features = false, optional = true }
 

primitive-types/impls/serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "impl-serde"
-version = "0.2.3"
+version = "0.3.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "Apache-2.0/MIT"

primitive-types/impls/serde/src/serialize.rs

@@ -11,7 +11,32 @@ use std::fmt;
 
 static CHARS: &[u8] = b"0123456789abcdef";
 
-fn to_hex<'a>(v: &'a mut [u8], bytes: &[u8], skip_leading_zero: bool) -> &'a str {
+/// Serialize given bytes to a 0x-prefixed hex string.
+///
+/// If `skip_leading_zero` initial 0s will not be printed out,
+/// unless the byte string is empty, in which case `0x0` will be returned.
+/// The results are consistent with `serialize_uint` output if the flag is
+/// on and `serialize_raw` if the flag is off.
+pub fn to_hex(bytes: &[u8], skip_leading_zero: bool) -> String {
+	let bytes = if skip_leading_zero {
+		let non_zero = bytes.iter().take_while(|b| **b == 0).count();
+		let bytes = &bytes[non_zero..];
+		if bytes.is_empty() {
+			return "0x0".into();
+		} else {
+			bytes
+		}
+	} else if bytes.is_empty() {
+		return "0x".into();
+	} else {
+		bytes
+	};
+
+	let mut slice = vec![0u8; (bytes.len() + 1) * 2];
+	to_hex_raw(&mut slice, bytes, skip_leading_zero).into()
+}
+
+fn to_hex_raw<'a>(v: &'a mut [u8], bytes: &[u8], skip_leading_zero: bool) -> &'a str {
 	assert!(v.len() > 1 + bytes.len() * 2);
 
 	v[0] = b'0';
@@ -36,6 +61,48 @@ fn to_hex<'a>(v: &'a mut [u8], bytes: &[u8], skip_leading_zero: bool) -> &'a str
 	unsafe { std::str::from_utf8_unchecked(&v[0..idx]) }
 }
 
+/// Decode given hex string into a vector of bytes.
+///
+/// Returns an error if the string is not prefixed with `0x`
+/// or non-hex characters are present.
+pub fn from_hex(v: &str) -> Result<Vec<u8>, String> {
+	if !v.starts_with("0x") {
+		return Err("0x prefix is missing".into());
+	}
+
+	let bytes_len = v.len() - 2;
+	let mut modulus = bytes_len % 2;
+	let mut bytes = vec![0u8; (bytes_len + 1) / 2];
+	let mut buf = 0;
+	let mut pos = 0;
+	for (idx, byte) in v.bytes().enumerate().skip(2) {
+		buf <<= 4;
+
+		match byte {
+			b'A'..=b'F' => buf |= byte - b'A' + 10,
+			b'a'..=b'f' => buf |= byte - b'a' + 10,
+			b'0'..=b'9' => buf |= byte - b'0',
+			b' ' | b'\r' | b'\n' | b'\t' => {
+				buf >>= 4;
+				continue;
+			}
+			b => {
+				let ch = char::from(b);
+				return Err(format!("invalid hex character: {}, at {}", ch, idx));
+			}
+		}
+
+		modulus += 1;
+		if modulus == 2 {
+			modulus = 0;
+			bytes[pos] = buf;
+			pos += 1;
+		}
+	}
+
+	Ok(bytes)
+}
+
 /// Serializes a slice of bytes.
 pub fn serialize_raw<S>(slice: &mut [u8], bytes: &[u8], serializer: S) -> Result<S::Ok, S::Error>
 where
@@ -44,7 +111,7 @@ where
 	if bytes.is_empty() {
 		serializer.serialize_str("0x")
 	} else {
-		serializer.serialize_str(to_hex(slice, bytes, false))
+		serializer.serialize_str(to_hex_raw(slice, bytes, false))
 	}
 }
 
@@ -69,7 +136,7 @@ where
 	if bytes.is_empty() {
 		serializer.serialize_str("0x0")
 	} else {
-		serializer.serialize_str(to_hex(slice, bytes, true))
+		serializer.serialize_str(to_hex_raw(slice, bytes, true))
 	}
 }
 
@@ -107,41 +174,7 @@ where
 		}
 
 		fn visit_str<E: de::Error>(self, v: &str) -> Result<Self::Value, E> {
-			if !v.starts_with("0x") {
-				return Err(E::custom("prefix is missing"));
-			}
-
-			let bytes_len = v.len() - 2;
-			let mut modulus = bytes_len % 2;
-			let mut bytes = vec![0u8; (bytes_len + 1) / 2];
-			let mut buf = 0;
-			let mut pos = 0;
-			for (idx, byte) in v.bytes().enumerate().skip(2) {
-				buf <<= 4;
-
-				match byte {
-					b'A'..=b'F' => buf |= byte - b'A' + 10,
-					b'a'..=b'f' => buf |= byte - b'a' + 10,
-					b'0'..=b'9' => buf |= byte - b'0',
-					b' ' | b'\r' | b'\n' | b'\t' => {
-						buf >>= 4;
-						continue;
-					}
-					b => {
-						let ch = char::from(b);
-						return Err(E::custom(&format!("invalid hex character: {}, at {}", ch, idx)));
-					}
-				}
-
-				modulus += 1;
-				if modulus == 2 {
-					modulus = 0;
-					bytes[pos] = buf;
-					pos += 1;
-				}
-			}
-
-			Ok(bytes)
+			from_hex(v).map_err(E::custom)
 		}
 
 		fn visit_string<E: de::Error>(self, v: String) -> Result<Self::Value, E> {
@@ -229,6 +262,7 @@ where
 
 #[cfg(test)]
 mod tests {
+	use super::*;
 	extern crate serde_derive;
 
 	use self::serde_derive::{Deserialize, Serialize};
@@ -278,4 +312,17 @@ mod tests {
 		let deserialized: Bytes = serde_json::from_str(&data).unwrap();
 		assert!(deserialized.0.is_empty())
 	}
+
+	#[test]
+	fn should_encode_to_and_from_hex() {
+		assert_eq!(to_hex(&[0, 1, 2], true), "0x102");
+		assert_eq!(to_hex(&[0, 1, 2], false), "0x000102");
+		assert_eq!(to_hex(&[0], true), "0x0");
+		assert_eq!(to_hex(&[], true), "0x0");
+		assert_eq!(to_hex(&[], false), "0x");
+		assert_eq!(to_hex(&[0], false), "0x00");
+		assert_eq!(from_hex("0x0102"), Ok(vec![1, 2]));
+		assert_eq!(from_hex("0x102"), Ok(vec![1, 2]));
+		assert_eq!(from_hex("0xf"), Ok(vec![0xf]));
+	}
 }