Add #![no_std] support

.github/workflows/rust.yml

@@ -44,10 +44,12 @@ jobs:
       # Rust will frequently add new warnings and checks.
       if: matrix.rust == 'msrv'
       run: echo RUSTFLAGS='-Dwarnings' >> $GITHUB_ENV
-    - run: rustup update
-    - run: cargo version
-    - run: cargo build --target ${{ matrix.target }}
-    - run: cargo test --target ${{ matrix.target }}
+    - uses: stellar/binaries@v30
+      with:
+        name: cargo-hack
+        version: 0.5.28
+    - run: cargo-hack hack build --feature-powerset --target ${{ matrix.target }}
+    - run: cargo-hack hack test --feature-powerset --target ${{ matrix.target }}
 
   publish-dry-run:
     if: startsWith(github.head_ref, 'release/')

Cargo.toml

@@ -11,22 +11,22 @@ edition = "2021"
 rust-version = "1.67.0"
 
 [features]
-default = []
-cli = ["dep:clap"]
+default = ["std"]
+std = []
+cli = ["std", "dep:clap"]
 
 [[bin]]
 name = "stellar-strkey"
 path = "src/bin/stellar-strkey/main.rs"
 required-features = ["cli"]
 doctest = false
 
-[build_dependencies]
+[build-dependencies]
 crate-git-revision = "0.0.6"
 
 [dev-dependencies]
 proptest = "1.0.0"
 
 [dependencies]
-data-encoding = "2.6.0"
-thiserror = "1.0.36"
+data-encoding = { version = "2.6.0", default-features = false, features = ["alloc"] }
 clap = { version = "4.2.4", default-features = false, features = ["std", "derive", "usage", "help"], optional = true }

README.md

@@ -16,6 +16,8 @@ To use the library, include in your toml:
 stellar-strkey = "..."
 ```
 
+By default, the library uses the standard library (std). If you want to use it in a `no_std` environment, you need to disable the `default` features and enable the `alloc` crate.
+
 #### CLI
 
 To use the CLI:

src/convert.rs

@@ -1,6 +1,9 @@
 // TODO: Could encode and decode, and the functions upstream that call them, be
 // const fn's?
 
+use alloc::string::String;
+use alloc::vec::Vec;
+
 use crate::{crc::checksum, error::DecodeError};
 
 pub fn encode(ver: u8, payload: &[u8]) -> String {

src/crc.rs

@@ -86,6 +86,7 @@ pub fn checksum(data: &[u8]) -> [u8; 2] {
 mod tests {
     use super::checksum;
     extern crate proptest;
+    use alloc::vec::Vec;
     use proptest::prelude::*;
 
     #[test]

src/ed25519.rs

@@ -1,19 +1,20 @@
-use std::{
-    fmt::{Debug, Display},
-    str::FromStr,
-};
-
 use crate::{
     convert::{decode, encode},
     error::DecodeError,
     version,
 };
 
+use alloc::{format, string::String, vec, vec::Vec};
+use core::{
+    fmt::{Debug, Display},
+    str::FromStr,
+};
+
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct PrivateKey(pub [u8; 32]);
 
 impl Debug for PrivateKey {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "PrivateKey(")?;
         write!(
             f,
@@ -51,7 +52,7 @@ impl PrivateKey {
 }
 
 impl Display for PrivateKey {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -68,7 +69,7 @@ impl FromStr for PrivateKey {
 pub struct PublicKey(pub [u8; 32]);
 
 impl Debug for PublicKey {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "PublicKey(")?;
         write!(
             f,
@@ -106,7 +107,7 @@ impl PublicKey {
 }
 
 impl Display for PublicKey {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -126,7 +127,7 @@ pub struct MuxedAccount {
 }
 
 impl Debug for MuxedAccount {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "MuxedAccount(")?;
         write!(
             f,
@@ -174,7 +175,7 @@ impl MuxedAccount {
 }
 
 impl Display for MuxedAccount {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -197,7 +198,7 @@ pub struct SignedPayload {
 }
 
 impl Debug for SignedPayload {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "MuxedAccount(")?;
         write!(
             f,
@@ -321,7 +322,7 @@ impl SignedPayload {
 }
 
 impl Display for SignedPayload {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }

src/error.rs

@@ -1,6 +1,18 @@
-#[derive(thiserror::Error, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
+use core::fmt;
+
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
 pub enum DecodeError {
     // TODO: Add meaningful errors for each problem that can occur.
-    #[error("the strkey is invalid")]
     Invalid,
 }
+
+impl fmt::Display for DecodeError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            DecodeError::Invalid => write!(f, "the strkey is invalid"),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for DecodeError {}

src/lib.rs

@@ -1,3 +1,9 @@
+#![no_std]
+extern crate alloc;
+
+#[cfg(feature = "std")]
+extern crate std;
+
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
 pub struct Version<'a> {
     pub pkg: &'a str,

src/strkey.rs

@@ -1,4 +1,8 @@
-use std::{fmt::Debug, fmt::Display, str::FromStr};
+use alloc::{format, string::String};
+use core::{
+    fmt::{Debug, Display},
+    str::FromStr,
+};
 
 use crate::{
     convert::{decode, encode},
@@ -55,7 +59,7 @@ impl Strkey {
 }
 
 impl Display for Strkey {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -72,7 +76,7 @@ impl FromStr for Strkey {
 pub struct PreAuthTx(pub [u8; 32]);
 
 impl Debug for PreAuthTx {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "PreAuthTx(")?;
         write!(
             f,
@@ -107,7 +111,7 @@ impl PreAuthTx {
 }
 
 impl Display for PreAuthTx {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -124,7 +128,7 @@ impl FromStr for PreAuthTx {
 pub struct HashX(pub [u8; 32]);
 
 impl Debug for HashX {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "HashX(")?;
         write!(
             f,
@@ -159,7 +163,7 @@ impl HashX {
 }
 
 impl Display for HashX {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }
@@ -176,7 +180,7 @@ impl FromStr for HashX {
 pub struct Contract(pub [u8; 32]);
 
 impl Debug for Contract {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "Contract(")?;
         write!(
             f,
@@ -211,7 +215,7 @@ impl Contract {
 }
 
 impl Display for Contract {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{}", self.to_string())
     }
 }

tests/tests.rs

@@ -1,8 +1,13 @@
-use stellar_strkey::*;
+#![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(not(feature = "std"))]
+extern crate alloc;
 extern crate proptest;
+use proptest::proptest;
+use stellar_strkey::*;
 
-use proptest::prelude::*;
+#[cfg(not(feature = "std"))]
+use alloc::{format, string::String, vec, vec::Vec};
 
 #[test]
 fn test_valid_public_keys() {