Implement ToAdviceInputs for MmrPeaks (#328)

* MmrPeaks ToAdviceInputs * use MmrPeaks::to_advice_inputs
0xPolygonMiden · Nov 30, 2023 · b8daebf · b8daebf
1 parent c57448a
commit b8daebf
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Showing 2 changed files with 30 additions and 21 deletions.
diff --git a/objects/src/advice.rs b/objects/src/advice.rs
@@ -1,6 +1,7 @@
 use super::{utils::collections::Vec, AdviceInputs, Felt, Word};
 use crate::crypto::merkle::InnerNodeInfo;
 use assembly::utils::IntoBytes;
+use miden_crypto::{merkle::MmrPeaks, ZERO};
 
 /// [AdviceInputsBuilder] trait specifies the interface for building advice inputs.
 /// The trait provides three methods for building advice inputs:
@@ -18,14 +19,6 @@ pub trait AdviceInputsBuilder {
     fn add_merkle_nodes<I: Iterator<Item = InnerNodeInfo>>(&mut self, nodes: I);
 }
 
-/// ToAdviceInputs trait specifies the interface for converting a rust object into advice inputs.
-pub trait ToAdviceInputs {
-    /// Converts the rust object into advice inputs and pushes them onto the given advice inputs
-    /// builder.
-    fn to_advice_inputs<T: AdviceInputsBuilder>(&self, target: &mut T);
-}
-
-/// Implement the `AdviceInputsBuilder` trait on `AdviceInputs`.
 impl AdviceInputsBuilder for AdviceInputs {
     fn push_onto_stack(&mut self, values: &[Felt]) {
         self.extend_stack(values.iter().copied());
@@ -39,3 +32,29 @@ impl AdviceInputsBuilder for AdviceInputs {
         self.extend_merkle_store(nodes);
     }
 }
+
+/// ToAdviceInputs trait specifies the interface for converting a rust object into advice inputs.
+pub trait ToAdviceInputs {
+    /// Converts the rust object into advice inputs and pushes them onto the given advice inputs
+    /// builder.
+    fn to_advice_inputs<T: AdviceInputsBuilder>(&self, target: &mut T);
+}
+
+// ToAdviceInputs IMPLEMENTATIONS
+// =================================================================================================
+
+impl ToAdviceInputs for MmrPeaks {
+    fn to_advice_inputs<T: AdviceInputsBuilder>(&self, target: &mut T) {
+        // create the vector of items to insert into the map
+        // The vector is in the following format:
+        //    elements[0]       = number of leaves in the Mmr
+        //    elements[1..4]    = padding ([Felt::ZERO; 3])
+        //    elements[4..]     = Mmr peak roots
+        let mut elements = vec![Felt::new(self.num_leaves() as u64), ZERO, ZERO, ZERO];
+        elements.extend(self.flatten_and_pad_peaks());
+
+        // insert the Mmr accumulator vector into the advice map against the Mmr root, which acts
+        // as the key.
+        target.insert_into_map(self.hash_peaks().into(), elements);
+    }
+}
diff --git a/objects/src/chain/mod.rs b/objects/src/chain/mod.rs
@@ -1,4 +1,4 @@
-use super::{crypto::merkle::Mmr, AdviceInputsBuilder, Felt, ToAdviceInputs, ZERO};
+use super::{crypto::merkle::Mmr, AdviceInputsBuilder, ToAdviceInputs};
 
 // TODO: Consider using a PartialMmr that only contains the Mmr nodes that are relevant to the
 // transaction being processed.
@@ -33,18 +33,8 @@ impl ToAdviceInputs for &ChainMmr {
         target.add_merkle_nodes(self.0.inner_nodes());
 
         // Extract Mmr accumulator
-        let accumulator = self.0.peaks(self.0.forest()).unwrap();
+        let peaks = self.0.peaks(self.0.forest()).unwrap();
 
-        // create the vector of items to insert into the map
-        // The vector is in the following format:
-        //    elements[0]       = number of leaves in the Mmr
-        //    elements[1..4]    = padding ([Felt::ZERO; 3])
-        //    elements[4..]     = Mmr peak roots
-        let mut elements = vec![Felt::new(accumulator.num_leaves() as u64), ZERO, ZERO, ZERO];
-        elements.extend(accumulator.flatten_and_pad_peaks());
-
-        // insert the Mmr accumulator vector into the advice map against the Mmr root, which acts
-        // as the key.
-        target.insert_into_map(accumulator.hash_peaks().into(), elements);
+        peaks.to_advice_inputs(target);
     }
 }