no-std-ify hpke-rs-crypto

Cargo.toml

@@ -25,6 +25,7 @@ hpke-test = []
 hpke-test-prng = []                                                     # ⚠️ Enable testing PRNG - DO NOT USE
 
 [dev-dependencies]
+hpke-rs-crypto = { version = "0.1.3", path = "./traits", features = ["std"] }
 serde_json = "1.0"
 serde = { version = "1.0", features = ["derive"] }
 lazy_static = "1.4"

traits/Cargo.toml

@@ -16,3 +16,4 @@ getrandom = { version = "0.2", features = ["js"] }
 
 [features]
 serde = ["dep:serde"]
+std = []

traits/src/error.rs

@@ -2,7 +2,8 @@
 //!
 //! Errors thrown by crypto functions implementing the [`crate::HpkeCrypto`] traits.
 
-use std::fmt::Display;
+use alloc::string::String;
+use core::fmt::Display;
 
 /// Errors thrown by [`crate::HpkeCrypto`] trait implementations.
 #[derive(Debug)]
@@ -41,10 +42,11 @@ pub enum Error {
     CryptoLibraryError(String),
 }
 
+#[cfg(feature = "std")]
 impl std::error::Error for Error {}
 
 impl Display for Error {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "HPKE Crypto Error: {:?}", self)
     }
 }

traits/src/lib.rs

@@ -1,4 +1,12 @@
 #![doc = include_str!("../Readme.md")]
+#![no_std]
+
+extern crate alloc;
+#[cfg(feature = "std")]
+extern crate std;
+
+use alloc::string::String;
+use alloc::vec::Vec;
 
 use error::Error;
 use types::{AeadAlgorithm, KemAlgorithm};

traits/src/types.rs

@@ -28,13 +28,13 @@ pub enum KemAlgorithm {
     DhKem448 = 0x0021,
 }
 
-impl std::fmt::Display for KemAlgorithm {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+impl core::fmt::Display for KemAlgorithm {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         write!(f, "{:?}", self)
     }
 }
 
-impl std::convert::TryFrom<u16> for KemAlgorithm {
+impl core::convert::TryFrom<u16> for KemAlgorithm {
     type Error = error::Error;
     fn try_from(x: u16) -> Result<KemAlgorithm, Self::Error> {
         match x {
@@ -90,13 +90,13 @@ pub enum AeadAlgorithm {
     HpkeExport = 0xFFFF,
 }
 
-impl std::fmt::Display for AeadAlgorithm {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+impl core::fmt::Display for AeadAlgorithm {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         write!(f, "{:?}", self)
     }
 }
 
-impl std::convert::TryFrom<u16> for AeadAlgorithm {
+impl core::convert::TryFrom<u16> for AeadAlgorithm {
     type Error = error::Error;
     fn try_from(x: u16) -> Result<AeadAlgorithm, Self::Error> {
         match x {
@@ -171,13 +171,13 @@ pub enum KdfAlgorithm {
     HkdfSha512 = 0x0003,
 }
 
-impl std::fmt::Display for KdfAlgorithm {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+impl core::fmt::Display for KdfAlgorithm {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         write!(f, "{:?}", self)
     }
 }
 
-impl std::convert::TryFrom<u16> for KdfAlgorithm {
+impl core::convert::TryFrom<u16> for KdfAlgorithm {
     type Error = error::Error;
     fn try_from(x: u16) -> Result<KdfAlgorithm, Self::Error> {
         match x {