From 949ff158fa24b9a04aba828da6c91f0cddd3fbd8 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Mon, 16 Dec 2024 17:19:26 +0000
Subject: [PATCH] halo2_poseidon: Add no-std support

---
 halo2_poseidon/Cargo.toml          |  4 ++--
 halo2_poseidon/src/grain.rs        |  2 +-
 halo2_poseidon/src/lib.rs          | 15 +++++++++++----
 halo2_poseidon/src/mds.rs          |  2 ++
 halo2_poseidon/src/p128pow5t3.rs   |  2 ++
 halo2_poseidon/src/test_vectors.rs |  2 ++
 6 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/halo2_poseidon/Cargo.toml b/halo2_poseidon/Cargo.toml
index 2831342e1b..c9945c84f7 100644
--- a/halo2_poseidon/Cargo.toml
+++ b/halo2_poseidon/Cargo.toml
@@ -15,8 +15,8 @@ readme = "README.md"
 categories = ["cryptography"]
 
 [dependencies]
-bitvec = "1"
-ff = "0.13"
+bitvec = { version = "1", default-features = false }
+ff = { version = "0.13", default-features = false }
 group = "0.13"
 pasta_curves = "0.5"
 
diff --git a/halo2_poseidon/src/grain.rs b/halo2_poseidon/src/grain.rs
index 8c8c9734cf..3c1efb80a1 100644
--- a/halo2_poseidon/src/grain.rs
+++ b/halo2_poseidon/src/grain.rs
@@ -1,6 +1,6 @@
 //! The Grain LFSR in self-shrinking mode, as used by Poseidon.
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 use bitvec::prelude::*;
 use group::ff::{Field, FromUniformBytes, PrimeField};
diff --git a/halo2_poseidon/src/lib.rs b/halo2_poseidon/src/lib.rs
index 7745db9f3d..db3e880302 100644
--- a/halo2_poseidon/src/lib.rs
+++ b/halo2_poseidon/src/lib.rs
@@ -1,9 +1,16 @@
 //! The Poseidon algebraic hash function.
 
-use std::convert::TryInto;
-use std::fmt;
-use std::iter;
-use std::marker::PhantomData;
+#![no_std]
+
+#[macro_use]
+extern crate alloc;
+
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::convert::TryInto;
+use core::fmt;
+use core::iter;
+use core::marker::PhantomData;
 
 use group::ff::{Field, FromUniformBytes, PrimeField};
 
diff --git a/halo2_poseidon/src/mds.rs b/halo2_poseidon/src/mds.rs
index bc633478cc..5345773c30 100644
--- a/halo2_poseidon/src/mds.rs
+++ b/halo2_poseidon/src/mds.rs
@@ -1,3 +1,5 @@
+use alloc::vec::Vec;
+
 use ff::FromUniformBytes;
 
 use super::{grain::Grain, Mds};
diff --git a/halo2_poseidon/src/p128pow5t3.rs b/halo2_poseidon/src/p128pow5t3.rs
index c7640cd7a0..37d2280654 100644
--- a/halo2_poseidon/src/p128pow5t3.rs
+++ b/halo2_poseidon/src/p128pow5t3.rs
@@ -1,3 +1,5 @@
+use alloc::vec::Vec;
+
 use ff::Field;
 use pasta_curves::{pallas::Base as Fp, vesta::Base as Fq};
 
diff --git a/halo2_poseidon/src/test_vectors.rs b/halo2_poseidon/src/test_vectors.rs
index d7ec29893f..9882297b64 100644
--- a/halo2_poseidon/src/test_vectors.rs
+++ b/halo2_poseidon/src/test_vectors.rs
@@ -1,5 +1,7 @@
 //! Test vectors for [`OrchardNullifier`].
 
+use alloc::vec::Vec;
+
 pub struct PermuteTestVector {
     pub initial_state: [[u8; 32]; 3],
     pub final_state: [[u8; 32]; 3],