Minor refactor to packNibbles and unpackNibbles and add additional te…

…sts. (#2162)

fluffy/network/state/state_content.nim

@@ -214,18 +214,17 @@ func packNibbles*(nibbles: seq[byte]): Nibbles =
  if nibbles.len() == 0:
  return Nibbles(@[byte(0x00)])
 
- let isOddLength = (nibbles.len() %% 2 == 1)
+ let isEvenLength = nibbles.len() mod 2 == 0
 
  var
- output = newSeq[byte]()
- highNibble = not isOddLength
+ output = newSeqOfCap[byte](nibbles.len() div 2 + 1)
+ highNibble = isEvenLength
  currentByte: byte = 0
 
- if isOddLength:
- currentByte = 0x10
-
- if not isOddLength:
+ if isEvenLength:
  output.add(0x00)
+ else:
+ currentByte = 0x10
 
  for i, nibble in nibbles:
  if highNibble:
@@ -240,7 +239,7 @@ func packNibbles*(nibbles: seq[byte]): Nibbles =
 func unpackNibbles*(nibbles: Nibbles): seq[byte] =
  doAssert(nibbles.len() <= MAX_PACKED_NIBBLES_LEN, "Packed nibbles length is too long")
 
- var output = newSeq[byte]()
+ var output = newSeqOfCap[byte](nibbles.len * 2)
 
  for i, pair in nibbles:
  if i == 0 and pair == 0x00:

fluffy/tests/state_network_tests/test_state_content_keys.nim

@@ -14,6 +14,45 @@ import
 const testVectorDir = "./vendor/portal-spec-tests/tests/mainnet/state/serialization/"
 
 suite "State Content Keys":
+ test "Encode/decode empty nibbles":
+ const
+ expected = "00"
+ nibbles: seq[byte] = @[]
+ packedNibbles = packNibbles(nibbles)
+ unpackedNibbles = unpackNibbles(packedNibbles)
+
+ let encoded = SSZ.encode(packedNibbles)
+
+ check:
+ encoded.toHex() == expected
+ unpackedNibbles == nibbles
+
+ test "Encode/decode zero nibble":
+ const
+ expected = "10"
+ nibbles: seq[byte] = @[0]
+ packedNibbles = packNibbles(nibbles)
+ unpackedNibbles = unpackNibbles(packedNibbles)
+
+ let encoded = SSZ.encode(packedNibbles)
+
+ check:
+ encoded.toHex() == expected
+ unpackedNibbles == nibbles
+
+ test "Encode/decode one nibble":
+ const
+ expected = "11"
+ nibbles: seq[byte] = @[1]
+ packedNibbles = packNibbles(nibbles)
+ unpackedNibbles = unpackNibbles(packedNibbles)
+
+ let encoded = SSZ.encode(packedNibbles)
+
+ check:
+ encoded.toHex() == expected
+ unpackedNibbles == nibbles
+
  test "Encode/decode even nibbles":
  const
  expected = "008679e8ed"
@@ -40,6 +79,25 @@ suite "State Content Keys":
  encoded.toHex() == expected
  unpackedNibbles == nibbles
 
+ test "Encode/decode max length nibbles":
+ const
+ expected = "008679e8eda65bd257638cf8cf09b8238888947cc3c0bea2aa2cc3f1c4ac7a3002"
+ nibbles: seq[byte] =
+ @[
+ 8, 6, 7, 9, 0xe, 8, 0xe, 0xd, 0xa, 6, 5, 0xb, 0xd, 2, 5, 7, 6, 3, 8, 0xc, 0xf,
+ 8, 0xc, 0xf, 0, 9, 0xb, 8, 2, 3, 8, 8, 8, 8, 9, 4, 7, 0xc, 0xc, 3, 0xc, 0,
+ 0xb, 0xe, 0xa, 2, 0xa, 0xa, 2, 0xc, 0xc, 3, 0xf, 1, 0xc, 4, 0xa, 0xc, 7, 0xa,
+ 3, 0, 0, 2,
+ ]
+ packedNibbles = packNibbles(nibbles)
+ unpackedNibbles = unpackNibbles(packedNibbles)
+
+ let encoded = SSZ.encode(packedNibbles)
+
+ check:
+ encoded.toHex() == expected
+ unpackedNibbles == nibbles
+
  test "Encode/decode AccountTrieNodeKey":
  const file = testVectorDir & "account_trie_node_key.yaml"