Update EIP-6110: Spec parse_deposit_data

EIPS/eip-6110.md

@@ -76,11 +76,35 @@ Beginning with the `FORK_BLOCK`, each deposit accumulated in the block **MUST**
 in the order they appear in the logs. To illustrate:
 
 ```python
-def parse_deposit_data(deposit_event_data) -> bytes[]:
-  """
-  Parses deposit data from DepositContract.DepositEvent data
-  """
-  pass
+def parse_deposit_data(deposit_event_data):
+    """
+    Parses raw emitted EVM log data to decode the request data
+    """
+
+
+    # These offsets points are data pointers which first encode the 
+    # size of the data (which is always 32 bytes)
+    # The data itself (of this size) is then appended after the size 32 bytes
+    PUBKEY_OFFSET = deposit_event_data[0:32]
+    WITHDRAWAL_CREDENTIALS_OFFSET = deposit_event_data[32:64]
+    AMOUNT_OFFSET = deposit_event_data[64:96]
+    SIGNATURE_OFFSET = deposit_event_data[96:128]
+    INDEX_OFFSET = deposit_event_data[128:160]
+
+    # These sizes are the sizes of the relevant data
+    PUBKEY_SIZE = deposit_event_data[PUBKEY_OFFSET:PUBKEY_OFFSET+32]
+    WITHDRAWAL_CREDENTIALS_SIZE = deposit_event_data[WITHDRAWAL_CREDENTIALS_OFFSET:WITHDRAWAL_CREDENTIALS_OFFSET+32]
+    AMOUNT_SIZE = deposit_event_data[AMOUNT_OFFSET:AMOUNT_OFFSET+32]
+    SIGNATURE_SIZE = deposit_event_data[SIGNATURE_OFFSET:SIGNATURE_OFFSET+32]
+    INDEX_SIZE = deposit_event_data[INDEX_OFFSET:INDEX_OFFSET+32]
+
+    pubkey = deposit_event_data[PUBKEY_OFFSET + 32:PUBKEY_OFFSET + 32 + PUBKEY_SIZE]
+    withdrawal_credentials = deposit_event_data[WITHDRAWAL_CREDENTIALS_OFFSET + 32:WITHDRAWAL_CREDENTIALS_OFFSET + 32 + WITHDRAWAL_CREDENTIALS_SIZE]
+    amount = deposit_event_data[AMOUNT_OFFSET + 32:AMOUNT_OFFSET + 32 + AMOUNT_SIZE]
+    signature = deposit_event_data[SIGNATURE_OFFSET + 32:SIGNATURE_OFFSET + 32 + SIGNATURE_SIZE]
+    index = deposit_event_data[INDEX_OFFSET + 32:INDEX_OFFSET + 32 + INDEX_SIZE]
+
+    return [pubkey, withdrawal_credentials, amount, signature, index]
 
 def event_data_to_deposit_request(deposit_event_data) -> bytes:
     deposit_data = parse_deposit_data(deposit_event_data)