Decompress parameters when reading

fawkes-crypto/src/backend/bellman_groth16/mod.rs

@@ -1,3 +1,4 @@
+use std::io::{Read, Write};
 use crate::{
     circuit::{
         cs::{RCS, WitnessCS, CS},
@@ -149,16 +150,25 @@ impl<E: Engine> Parameters<E> {
 
     pub fn write<W:std::io::Write>(&self, writer: &mut W) -> std::io::Result<()> {
         let bitvec_len = self.3.len() as u32;
+
+        let mut gates = Vec::new();
+        let mut w = brotli::CompressorWriter::new(&mut gates, 4096, 9, 22);
+        w.write_all(&self.2)?;
+        drop(w);
+
         BorshSerialize::serialize(&self.1, writer)?;
-        BorshSerialize::serialize(&self.2, writer)?;
+        BorshSerialize::serialize(&gates, writer)?;
         BorshSerialize::serialize(&bitvec_len, writer)?;
         BorshSerialize::serialize(&self.3.to_bytes(), writer)?;
         self.0.write(writer)
     }
 
     pub fn read(reader: &mut &[u8], disallow_points_at_infinity: bool, checked: bool) -> std::io::Result<Self> {
         let e1 = BorshDeserialize::deserialize(reader)?;
-        let e2 = BorshDeserialize::deserialize(reader)?;
+        let e2_compressed: Vec<u8> = BorshDeserialize::deserialize(reader)?;
+        let mut e2 = Vec::new();
+        brotli::Decompressor::new(e2_compressed.as_slice(), 1024).read_to_end(&mut e2)?;
+
         let e3_len = <u32 as BorshDeserialize>::deserialize(reader)? as usize;
         let e3_buf:Vec<u8> = BorshDeserialize::deserialize(reader)?;
 

fawkes-crypto/src/backend/bellman_groth16/setup.rs

@@ -22,14 +22,13 @@ pub fn setup<E: Engine, Pub: Signal<BuildCS<E::Fr>>, Sec: Signal<BuildCS<E::Fr>>
 
     let num_gates = cs.gates.len();
 
-    let mut buf = std::io::Cursor::new(vec![]);
-    let mut c = brotli::CompressorWriter::new(&mut buf, 4096, 9, 22);
+    let mut buf = vec![];
+    let mut c = &mut buf;
     for g in cs.gates.iter() {
         c.write_all(&g.try_to_vec().unwrap()).unwrap();
     }
 
     c.flush().unwrap();
-    drop(c);
 
-    Parameters(bp, num_gates as u32, buf.into_inner(), cs.const_tracker.clone())
+    Parameters(bp, num_gates as u32, buf, cs.const_tracker.clone())
 }

fawkes-crypto/src/circuit/r1cs/cs.rs

@@ -225,7 +225,7 @@ impl<Fr:PrimeField, R:std::io::Read> Iterator for GateStreamedIterator<Fr, R> {
 impl<'a, Fr: PrimeField> CS for WitnessCS<'a, Fr> {
     type Fr = Fr;
     type LC = ZeroLC;
-    type GateIterator = GateStreamedIterator<Fr, brotli::Decompressor<&'a [u8]>>;
+    type GateIterator = GateStreamedIterator<Fr, &'a [u8]>;
 
     fn num_gates(&self) -> usize {
         self.num_gates
@@ -246,7 +246,7 @@ impl<'a, Fr: PrimeField> CS for WitnessCS<'a, Fr> {
     }
 
     fn get_gate_iterator(&self) -> Self::GateIterator {
-        GateStreamedIterator(brotli::Decompressor::new(self.gates_data, 4096), PhantomData)
+        GateStreamedIterator(&self.gates_data, PhantomData)
     }
 
     fn enforce(_: &CNum<Self>, _: &CNum<Self>, _: &CNum<Self>) {