From 611e4d260446b1b5c647fc4369d8a43145d0ae29 Mon Sep 17 00:00:00 2001
From: dharjeezy <dharjeezy@gmail.com>
Date: Tue, 1 Sep 2026 11:06:20 +0100
Subject: [PATCH 1/3] Support no_std builds

---
 Cargo.toml                 | 12 ++++++++----
 src/address_hex.rs         |  3 ++-
 src/b256_hex.rs            |  1 +
 src/fixed_bytes_hex.rs     |  1 +
 src/hex.rs                 |  3 ++-
 src/hex_vec.rs             |  1 +
 src/json_str.rs            |  1 +
 src/lib.rs                 |  6 ++++++
 src/list_of_bytes_lists.rs |  3 ++-
 src/quoted_int.rs          |  9 +++++----
 src/quoted_u64_vec.rs      |  3 ++-
 src/u256_dec.rs            |  1 +
 src/u256_hex_be.rs         |  5 +++--
 src/u32_hex.rs             |  1 +
 src/u64_hex_be.rs          |  3 ++-
 src/u8_hex.rs              |  1 +
 16 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 7801efb..32428b7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,8 +14,12 @@ categories = ["cryptography::cryptocurrencies"]
 name = "serde_utils"
 
 [dependencies]
-alloy-primitives = { version = "1.0", features = ["serde"] }
-serde = { version = "1.0.0", features = ["derive"] }
+alloy-primitives = { version = "1.0", default-features = false, features = ["serde"] }
+serde = { version = "1.0.0", default-features = false, features = ["derive", "alloc"] }
 serde_derive = "1.0.0"
-serde_json = "1.0.0"
-hex = "0.4.3"
+serde_json = { version = "1.0.0", default-features = false, features = ["alloc"] }
+hex = { version = "0.4.3", default-features = false, features = ["alloc"] }
+
+[features]
+default = ["std"]
+std = ["alloy-primitives/std", "serde/std", "serde_json/std", "hex/std"]
diff --git a/src/address_hex.rs b/src/address_hex.rs
index 1b39b15..8030378 100644
--- a/src/address_hex.rs
+++ b/src/address_hex.rs
@@ -1,3 +1,4 @@
+use alloc::{format, string::{String, ToString}};
 use alloy_primitives::Address;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
@@ -35,7 +36,7 @@ where
 
 #[cfg(test)]
 mod test {
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     use alloy_primitives::Address;
     use serde::{Deserialize, Serialize};
diff --git a/src/b256_hex.rs b/src/b256_hex.rs
index 8a2ddc1..0965637 100644
--- a/src/b256_hex.rs
+++ b/src/b256_hex.rs
@@ -1,3 +1,4 @@
+use alloc::{format, string::{String, ToString}};
 use alloy_primitives::B256;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
diff --git a/src/fixed_bytes_hex.rs b/src/fixed_bytes_hex.rs
index 438db57..3121647 100644
--- a/src/fixed_bytes_hex.rs
+++ b/src/fixed_bytes_hex.rs
@@ -2,6 +2,7 @@
 //!
 //! E.g., `[0, 1, 2, 3]` serializes as `"0x00010203"`.
 
+use alloc::{format, string::{String, ToString}};
 use crate::hex::PrefixedHexVisitor;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
diff --git a/src/hex.rs b/src/hex.rs
index 9a2cd65..e068799 100644
--- a/src/hex.rs
+++ b/src/hex.rs
@@ -1,7 +1,8 @@
 //! Provides utilities for parsing 0x-prefixed hex strings.
 
+use alloc::{format, string::{String, ToString}, vec::Vec};
 use serde::de::{self, Visitor};
-use std::fmt;
+use core::fmt;
 
 /// Encode `data` as a 0x-prefixed hex string.
 pub fn encode<T: AsRef<[u8]>>(data: T) -> String {
diff --git a/src/hex_vec.rs b/src/hex_vec.rs
index 08a0d00..37ad8f8 100644
--- a/src/hex_vec.rs
+++ b/src/hex_vec.rs
@@ -2,6 +2,7 @@
 //!
 //! E.g., `vec![0, 1, 2, 3]` serializes as `"0x00010203"`.
 
+use alloc::{string::{String, ToString}, vec::Vec};
 use crate::hex::PrefixedHexVisitor;
 use serde::{Deserializer, Serializer};
 
diff --git a/src/json_str.rs b/src/json_str.rs
index d007cf5..f610ca5 100644
--- a/src/json_str.rs
+++ b/src/json_str.rs
@@ -1,4 +1,5 @@
 //! Serialize a datatype as a JSON-blob within a single string.
+use alloc::string::String;
 use serde::{
     de::{DeserializeOwned, Error as _},
     ser::Error as _,
diff --git a/src/lib.rs b/src/lib.rs
index a2a1f64..9252ff4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,9 @@
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[macro_use]
+extern crate alloc;
+
+
 mod quoted_int;
 
 pub mod address_hex;
diff --git a/src/list_of_bytes_lists.rs b/src/list_of_bytes_lists.rs
index c7007c3..f45040b 100644
--- a/src/list_of_bytes_lists.rs
+++ b/src/list_of_bytes_lists.rs
@@ -4,6 +4,7 @@
 //!
 //! Quotes can be optional during decoding.
 
+use alloc::{string::String, vec::Vec};
 use crate::hex;
 use serde::ser::SerializeSeq;
 use serde::{de, Deserializer, Serializer};
@@ -12,7 +13,7 @@ pub struct ListOfBytesListVisitor;
 impl<'a> serde::de::Visitor<'a> for ListOfBytesListVisitor {
     type Value = Vec<Vec<u8>>;
 
-    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+    fn expecting(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
         write!(formatter, "a list of 0x-prefixed byte lists")
     }
 
diff --git a/src/quoted_int.rs b/src/quoted_int.rs
index 3a7d9eb..63e2b20 100644
--- a/src/quoted_int.rs
+++ b/src/quoted_int.rs
@@ -4,11 +4,12 @@
 //!
 //! Quotes can be optional during decoding.
 
+use alloc::format;
 use alloy_primitives::U256;
 use serde::{Deserializer, Serializer};
 use serde_derive::{Deserialize, Serialize};
-use std::convert::TryFrom;
-use std::marker::PhantomData;
+use core::convert::TryFrom;
+use core::marker::PhantomData;
 
 macro_rules! define_mod {
     ($int: ty) => {
@@ -26,7 +27,7 @@ macro_rules! define_mod {
         {
             type Value = T;
 
-            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+            fn expecting(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
                 if self.require_quotes {
                     write!(formatter, "a quoted integer")
                 } else {
@@ -169,7 +170,7 @@ pub mod quoted_u256 {
     impl<'de> serde::de::Visitor<'de> for U256Visitor {
         type Value = U256;
 
-        fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        fn expecting(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
             formatter.write_str("a quoted U256 integer")
         }
 
diff --git a/src/quoted_u64_vec.rs b/src/quoted_u64_vec.rs
index f124c98..0380d69 100644
--- a/src/quoted_u64_vec.rs
+++ b/src/quoted_u64_vec.rs
@@ -4,6 +4,7 @@
 //!
 //! Quotes can be optional during decoding.
 
+use alloc::vec::Vec;
 use serde::ser::SerializeSeq;
 use serde::{Deserializer, Serializer};
 use serde_derive::{Deserialize, Serialize};
@@ -19,7 +20,7 @@ pub struct QuotedIntVecVisitor;
 impl<'a> serde::de::Visitor<'a> for QuotedIntVecVisitor {
     type Value = Vec<u64>;
 
-    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+    fn expecting(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
         write!(formatter, "a list of quoted or unquoted integers")
     }
 
diff --git a/src/u256_dec.rs b/src/u256_dec.rs
index 5163dc1..822c4d4 100644
--- a/src/u256_dec.rs
+++ b/src/u256_dec.rs
@@ -1,3 +1,4 @@
+use alloc::{format, string::{String, ToString}};
 use alloy_primitives::U256;
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 
diff --git a/src/u256_hex_be.rs b/src/u256_hex_be.rs
index 3d7bdca..f16bfa5 100644
--- a/src/u256_hex_be.rs
+++ b/src/u256_hex_be.rs
@@ -1,8 +1,9 @@
+use alloc::{format, string::{String, ToString}};
 use alloy_primitives::U256;
 use serde::de::Visitor;
 use serde::{de, Deserializer, Serialize, Serializer};
-use std::fmt;
-use std::str::FromStr;
+use core::fmt;
+use core::str::FromStr;
 
 pub fn serialize<S>(num: &U256, serializer: S) -> Result<S::Ok, S::Error>
 where
diff --git a/src/u32_hex.rs b/src/u32_hex.rs
index ab41eab..ad85915 100644
--- a/src/u32_hex.rs
+++ b/src/u32_hex.rs
@@ -2,6 +2,7 @@
 //!
 //! E.g., `0` serializes as `"0x00000000"`.
 
+use alloc::format;
 use crate::bytes_4_hex;
 use serde::{Deserializer, Serializer};
 
diff --git a/src/u64_hex_be.rs b/src/u64_hex_be.rs
index e3364a2..659097f 100644
--- a/src/u64_hex_be.rs
+++ b/src/u64_hex_be.rs
@@ -2,9 +2,10 @@
 //!
 //! E.g., `0` serializes as `"0x0000000000000000"`.
 
+use alloc::{format, vec::Vec};
 use serde::de::{self, Error, Visitor};
 use serde::{Deserializer, Serializer};
-use std::fmt;
+use core::fmt;
 
 const BYTES_LEN: usize = 8;
 
diff --git a/src/u8_hex.rs b/src/u8_hex.rs
index c75d2af..6b97f25 100644
--- a/src/u8_hex.rs
+++ b/src/u8_hex.rs
@@ -2,6 +2,7 @@
 //!
 //! E.g., `0` serializes as `"0x00"`.
 
+use alloc::format;
 use crate::hex::PrefixedHexVisitor;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};

From 398a722fcd97de687eee7a56a7569cdbd17f38f3 Mon Sep 17 00:00:00 2001
From: dharjeezy <dharjeezy@gmail.com>
Date: Fri, 4 Sep 2026 10:50:03 +0100
Subject: [PATCH 2/3] Apply rustfmt

---
 src/address_hex.rs         | 5 ++++-
 src/b256_hex.rs            | 5 ++++-
 src/fixed_bytes_hex.rs     | 5 ++++-
 src/hex.rs                 | 8 ++++++--
 src/hex_vec.rs             | 5 ++++-
 src/lib.rs                 | 1 -
 src/list_of_bytes_lists.rs | 2 +-
 src/quoted_int.rs          | 4 ++--
 src/u256_dec.rs            | 5 ++++-
 src/u256_hex_be.rs         | 9 ++++++---
 src/u32_hex.rs             | 2 +-
 src/u64_hex_be.rs          | 2 +-
 src/u8_hex.rs              | 2 +-
 13 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/src/address_hex.rs b/src/address_hex.rs
index 8030378..53fb61a 100644
--- a/src/address_hex.rs
+++ b/src/address_hex.rs
@@ -1,4 +1,7 @@
-use alloc::{format, string::{String, ToString}};
+use alloc::{
+    format,
+    string::{String, ToString},
+};
 use alloy_primitives::Address;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
diff --git a/src/b256_hex.rs b/src/b256_hex.rs
index 0965637..8033658 100644
--- a/src/b256_hex.rs
+++ b/src/b256_hex.rs
@@ -1,4 +1,7 @@
-use alloc::{format, string::{String, ToString}};
+use alloc::{
+    format,
+    string::{String, ToString},
+};
 use alloy_primitives::B256;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
diff --git a/src/fixed_bytes_hex.rs b/src/fixed_bytes_hex.rs
index 3121647..2408e27 100644
--- a/src/fixed_bytes_hex.rs
+++ b/src/fixed_bytes_hex.rs
@@ -2,8 +2,11 @@
 //!
 //! E.g., `[0, 1, 2, 3]` serializes as `"0x00010203"`.
 
-use alloc::{format, string::{String, ToString}};
 use crate::hex::PrefixedHexVisitor;
+use alloc::{
+    format,
+    string::{String, ToString},
+};
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
 
diff --git a/src/hex.rs b/src/hex.rs
index e068799..94a76d3 100644
--- a/src/hex.rs
+++ b/src/hex.rs
@@ -1,8 +1,12 @@
 //! Provides utilities for parsing 0x-prefixed hex strings.
 
-use alloc::{format, string::{String, ToString}, vec::Vec};
-use serde::de::{self, Visitor};
+use alloc::{
+    format,
+    string::{String, ToString},
+    vec::Vec,
+};
 use core::fmt;
+use serde::de::{self, Visitor};
 
 /// Encode `data` as a 0x-prefixed hex string.
 pub fn encode<T: AsRef<[u8]>>(data: T) -> String {
diff --git a/src/hex_vec.rs b/src/hex_vec.rs
index 37ad8f8..1bf4c90 100644
--- a/src/hex_vec.rs
+++ b/src/hex_vec.rs
@@ -2,8 +2,11 @@
 //!
 //! E.g., `vec![0, 1, 2, 3]` serializes as `"0x00010203"`.
 
-use alloc::{string::{String, ToString}, vec::Vec};
 use crate::hex::PrefixedHexVisitor;
+use alloc::{
+    string::{String, ToString},
+    vec::Vec,
+};
 use serde::{Deserializer, Serializer};
 
 pub fn serialize<S>(bytes: &[u8], serializer: S) -> Result<S::Ok, S::Error>
diff --git a/src/lib.rs b/src/lib.rs
index 9252ff4..f148844 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,7 +3,6 @@
 #[macro_use]
 extern crate alloc;
 
-
 mod quoted_int;
 
 pub mod address_hex;
diff --git a/src/list_of_bytes_lists.rs b/src/list_of_bytes_lists.rs
index f45040b..5a160ea 100644
--- a/src/list_of_bytes_lists.rs
+++ b/src/list_of_bytes_lists.rs
@@ -4,8 +4,8 @@
 //!
 //! Quotes can be optional during decoding.
 
-use alloc::{string::String, vec::Vec};
 use crate::hex;
+use alloc::{string::String, vec::Vec};
 use serde::ser::SerializeSeq;
 use serde::{de, Deserializer, Serializer};
 
diff --git a/src/quoted_int.rs b/src/quoted_int.rs
index 63e2b20..ee2ee97 100644
--- a/src/quoted_int.rs
+++ b/src/quoted_int.rs
@@ -6,10 +6,10 @@
 
 use alloc::format;
 use alloy_primitives::U256;
-use serde::{Deserializer, Serializer};
-use serde_derive::{Deserialize, Serialize};
 use core::convert::TryFrom;
 use core::marker::PhantomData;
+use serde::{Deserializer, Serializer};
+use serde_derive::{Deserialize, Serialize};
 
 macro_rules! define_mod {
     ($int: ty) => {
diff --git a/src/u256_dec.rs b/src/u256_dec.rs
index 822c4d4..36b80e6 100644
--- a/src/u256_dec.rs
+++ b/src/u256_dec.rs
@@ -1,4 +1,7 @@
-use alloc::{format, string::{String, ToString}};
+use alloc::{
+    format,
+    string::{String, ToString},
+};
 use alloy_primitives::U256;
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 
diff --git a/src/u256_hex_be.rs b/src/u256_hex_be.rs
index f16bfa5..351cd6b 100644
--- a/src/u256_hex_be.rs
+++ b/src/u256_hex_be.rs
@@ -1,9 +1,12 @@
-use alloc::{format, string::{String, ToString}};
+use alloc::{
+    format,
+    string::{String, ToString},
+};
 use alloy_primitives::U256;
-use serde::de::Visitor;
-use serde::{de, Deserializer, Serialize, Serializer};
 use core::fmt;
 use core::str::FromStr;
+use serde::de::Visitor;
+use serde::{de, Deserializer, Serialize, Serializer};
 
 pub fn serialize<S>(num: &U256, serializer: S) -> Result<S::Ok, S::Error>
 where
diff --git a/src/u32_hex.rs b/src/u32_hex.rs
index ad85915..6f46764 100644
--- a/src/u32_hex.rs
+++ b/src/u32_hex.rs
@@ -2,8 +2,8 @@
 //!
 //! E.g., `0` serializes as `"0x00000000"`.
 
-use alloc::format;
 use crate::bytes_4_hex;
+use alloc::format;
 use serde::{Deserializer, Serializer};
 
 pub fn serialize<S>(num: &u32, serializer: S) -> Result<S::Ok, S::Error>
diff --git a/src/u64_hex_be.rs b/src/u64_hex_be.rs
index 659097f..5dae191 100644
--- a/src/u64_hex_be.rs
+++ b/src/u64_hex_be.rs
@@ -3,9 +3,9 @@
 //! E.g., `0` serializes as `"0x0000000000000000"`.
 
 use alloc::{format, vec::Vec};
+use core::fmt;
 use serde::de::{self, Error, Visitor};
 use serde::{Deserializer, Serializer};
-use core::fmt;
 
 const BYTES_LEN: usize = 8;
 
diff --git a/src/u8_hex.rs b/src/u8_hex.rs
index 6b97f25..df5ff7c 100644
--- a/src/u8_hex.rs
+++ b/src/u8_hex.rs
@@ -2,8 +2,8 @@
 //!
 //! E.g., `0` serializes as `"0x00"`.
 
-use alloc::format;
 use crate::hex::PrefixedHexVisitor;
+use alloc::format;
 use serde::de::Error;
 use serde::{Deserializer, Serializer};
 

From d2d558eadf7b304c4a1afb74a1eb2afd39404ba5 Mon Sep 17 00:00:00 2001
From: dharjeezy <dharjeezy@gmail.com>
Date: Fri, 4 Sep 2026 10:57:58 +0100
Subject: [PATCH 3/3] Satisfy the current clippy lints

---
 src/address_hex.rs | 2 +-
 src/b256_hex.rs    | 2 +-
 src/u64_hex_be.rs  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/address_hex.rs b/src/address_hex.rs
index 53fb61a..70aba46 100644
--- a/src/address_hex.rs
+++ b/src/address_hex.rs
@@ -13,7 +13,7 @@ where
     S: Serializer,
 {
     let mut hex_string: String = "0x".to_string();
-    hex_string.push_str(&hex::encode(&address));
+    hex_string.push_str(&hex::encode(address));
 
     serializer.serialize_str(&hex_string)
 }
diff --git a/src/b256_hex.rs b/src/b256_hex.rs
index 8033658..608c9b2 100644
--- a/src/b256_hex.rs
+++ b/src/b256_hex.rs
@@ -13,7 +13,7 @@ where
     S: Serializer,
 {
     let mut hex_string: String = "0x".to_string();
-    hex_string.push_str(&hex::encode(&hash));
+    hex_string.push_str(&hex::encode(hash));
 
     serializer.serialize_str(&hex_string)
 }
diff --git a/src/u64_hex_be.rs b/src/u64_hex_be.rs
index 5dae191..7b0a9fa 100644
--- a/src/u64_hex_be.rs
+++ b/src/u64_hex_be.rs
@@ -36,7 +36,7 @@ impl<'de> Visitor<'de> for QuantityVisitor {
             Ok(vec![0])
         } else if stripped.starts_with('0') {
             Err(de::Error::custom("cannot have leading zero"))
-        } else if stripped.len() % 2 != 0 {
+        } else if !stripped.len().is_multiple_of(2) {
             hex::decode(format!("0{}", stripped))
                 .map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))
         } else {