SSZ impl. rework started, see issue 1064

test_libs/pyspec/eth2spec/utils/merkle_minimal.py

@@ -1,7 +1,9 @@
 from .hash_function import hash
 
 
-zerohashes = [b'\x00' * 32]
+ZERO_BYTES32 = b'\x00' * 32
+
+zerohashes = [ZERO_BYTES32]
 for layer in range(1, 32):
     zerohashes.append(hash(zerohashes[layer - 1] + zerohashes[layer - 1]))
 
@@ -28,3 +30,31 @@ def get_merkle_proof(tree, item_index):
         subindex = (item_index // 2**i) ^ 1
         proof.append(tree[i][subindex] if subindex < len(tree[i]) else zerohashes[i])
     return proof
+
+
+def next_power_of_two(v: int) -> int:
+    """
+    Get the next power of 2. (for 64 bit range ints)
+    Examples:
+    0 -> 0, 1 -> 1, 2 -> 2, 3 -> 4, 32 -> 32, 33 -> 64
+    """
+    # effectively fill the bitstring (1 less, do not want to  with ones, then increment for next power of 2.
+    v -= 1
+    v |= v >> (1 << 0)
+    v |= v >> (1 << 1)
+    v |= v >> (1 << 2)
+    v |= v >> (1 << 3)
+    v |= v >> (1 << 4)
+    v |= v >> (1 << 5)
+    v += 1
+    return v
+
+
+def merkleize_chunks(chunks):
+    tree = chunks[::]
+    margin = next_power_of_two(len(chunks)) - len(chunks)
+    tree.extend([ZERO_BYTES32] * margin)
+    tree = [ZERO_BYTES32] * len(tree) + tree
+    for i in range(len(tree) // 2 - 1, 0, -1):
+        tree[i] = hash(tree[i * 2] + tree[i * 2 + 1])
+    return tree[1]