simplify padding calculation

Author: illuzen

src/lib.rs

@@ -1475,8 +1475,7 @@ mod tests {
         let mut expected = vec![
             0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
             0x30, // 8-byte leaf header (nibble_count=2, type=3)
-            0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-            0x00, // key data (felt-aligned to 8 bytes)
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xaa, // left-padded
         ];
         expected.extend_from_slice(&to_u64_le_bytes(1)); // length of value in bytes as 8-byte little-endian
         expected.extend_from_slice(&[0xbb, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]); // value data (felt-aligned to 8 bytes)

src/node_codec.rs

@@ -184,8 +184,7 @@ where
                     / nibble_ops::NIBBLE_PER_BYTE;
 
                 // Calculate prefix padding to ensure partial key data aligns to felt boundaries
-                let partial_start_offset = 8 + nibble_bytes.saturating_sub(24);
-                let misalignment = partial_start_offset % 8;
+                let misalignment = nibble_bytes % 8;
                 let prefix_padding = if misalignment == 0 { 0 } else { 8 - misalignment };
                 let total_nibble_section = ((prefix_padding + nibble_bytes + 7) / 8) * 8;
 
@@ -367,9 +366,8 @@ fn partial_from_iterator_encode<I: Iterator<Item = u8>>(
     let (prefix_padding, total_nibble_section) = match node_kind {
         NodeKind::Leaf | NodeKind::HashedValueLeaf => {
             // Calculate prefix padding to ensure proper felt boundary alignment
-            // for ZK proof verification
-            let partial_start_offset = 8 + nibble_bytes.saturating_sub(24);
-            let misalignment = partial_start_offset % 8;
+            // for ZK proof verification - align partial data to end at felt boundary
+            let misalignment = nibble_bytes % 8;
             let prefix_pad = if misalignment == 0 { 0 } else { 8 - misalignment };
             let total_section = ((prefix_pad + nibble_bytes + 7) / 8) * 8;
             (prefix_pad, total_section)

src/trie_stream.rs

@@ -74,9 +74,8 @@ fn fuse_nibbles_node(nibbles: &[u8], kind: NodeKind) -> Vec<u8> {
     // For leaf nodes, ensure partial key data aligns to felt boundaries
     let (prefix_padding, total_nibble_section) = match kind {
         NodeKind::Leaf | NodeKind::HashedValueLeaf => {
-            // Calculate prefix padding to ensure proper felt boundary alignment
-            let partial_start_offset = 8 + nibble_bytes.saturating_sub(24);
-            let misalignment = partial_start_offset % 8;
+            // Calculate prefix padding to ensure felt boundary alignment
+            let misalignment = nibble_bytes % 8;
             let prefix_pad = if misalignment == 0 { 0 } else { 8 - misalignment };
             let total_section = ((prefix_pad + nibble_bytes + 7) / 8) * 8;
             (prefix_pad, total_section)