WIP can't use itertools because rust-itertools/itertools#499

EspressoSystems · Sep 27, 2023 · ebecb87 · ebecb87
1 parent db8ebca
commit ebecb87
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Showing 2 changed files with 54 additions and 3 deletions.
diff --git a/utilities/Cargo.toml b/utilities/Cargo.toml
@@ -9,10 +9,11 @@ rust-version = { workspace = true }
 
 [dependencies]
 ark-ec = { version = "0.4.0", default-features = false }
-ark-ff = { version = "0.4.0", default-features = false, features = [ "asm" ] }
+ark-ff = { version = "0.4.0", default-features = false, features = ["asm"] }
 ark-serialize = { version = "0.4.0", default-features = false }
 ark-std = { version = "0.4.0", default-features = false }
 digest = { version = "0.10.1", default-features = false }
+itertools = { workspace = true }
 rayon = { version = "1.5.0", optional = true }
 serde = { version = "1.0", default-features = false, features = ["derive"] }
 sha2 = { version = "0.10.1", default-features = false }
@@ -28,5 +29,18 @@ ark-ed-on-bn254 = "0.4.0"
 
 [features]
 default = []
-std = ["ark-ff/std", "ark-std/std", "ark-ec/std", "ark-serialize/std", "digest/std", "serde/std", "sha2/std"]
-parallel = ["ark-ff/parallel", "ark-std/parallel", "ark-ec/parallel", "dep:rayon"]
+std = [
+    "ark-ff/std",
+    "ark-std/std",
+    "ark-ec/std",
+    "ark-serialize/std",
+    "digest/std",
+    "serde/std",
+    "sha2/std",
+]
+parallel = [
+    "ark-ff/parallel",
+    "ark-std/parallel",
+    "ark-ec/parallel",
+    "dep:rayon",
+]
diff --git a/utilities/src/conversion.rs b/utilities/src/conversion.rs
@@ -10,9 +10,11 @@ use ark_std::{
     borrow::Borrow,
     cmp::min,
     iter::{once, repeat},
+    marker::PhantomData,
     mem,
     vec::Vec,
 };
+use itertools::{Chunks, IntoChunks, Itertools};
 use sha2::{Digest, Sha512};
 
 /// Convert a scalar field element to a base field element.
@@ -289,6 +291,41 @@ fn compile_time_checks<F: Field>() -> (usize, usize, usize) {
     (primefield_bytes_len, extension_degree, field_bytes_len)
 }
 
+// pub fn bytes_to_field_elements<B, F>(bytes: B) -> impl Iterator<Item = F>
+// where
+//     F: Field,
+//     B: IntoIterator,
+//     B::Item: Borrow<u8>,
+// {
+// }
+
+pub struct FieldElems<'a, I: Iterator, F> {
+    into_chunks_iter: IntoChunks<I>,
+    chunks_iter: Chunks<'a, I>,
+    final_byte_len: Option<usize>,
+    _phantom: PhantomData<F>,
+    primefield_bytes_len: usize,
+    extension_degree: usize,
+    field_bytes_len: usize,
+}
+
+impl<I: Iterator, F: Field> FieldElems<'_, I, F> {
+    pub(crate) fn new(iter: I) -> Self {
+        let (primefield_bytes_len, extension_degree, field_bytes_len) = compile_time_checks::<F>();
+        let into_chunks_iter = iter.chunks(field_bytes_len);
+        let chunks_iter = into_chunks_iter.into_iter();
+        Self {
+            into_chunks_iter,
+            chunks_iter,
+            final_byte_len: None,
+            _phantom: PhantomData,
+            primefield_bytes_len,
+            extension_degree,
+            field_bytes_len,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::test_rng;