Calculate TransactionOutput.script_public_key_type to avoid having to…

… store it.

helper/PublicKeyType.py

@@ -0,0 +1,44 @@
+SCRIPT_CLASS_PUB_KEY = 'pubkey'
+SCRIPT_CLASS_PUB_KEY_ECDSA = 'pubkeyecdsa'
+SCRIPT_CLASS_SCRIPT_HASH = 'scripthash'
+SCRIPT_CLASS_NON_STANDARD = 'nonstandard'
+
+
+# Get the public_key_type for a public key.
+# The types are PubKey, PubKeyECDSA, ScriptHash and NonStandard
+def get_public_key_type(public_key):
+    if public_key is None:
+        return None
+    public_key_bytes = bytes.fromhex(public_key)
+    if is_pay_to_pubkey(public_key_bytes):
+        return SCRIPT_CLASS_PUB_KEY
+    if is_pay_to_pubkey_ecdsa(public_key_bytes):
+        return SCRIPT_CLASS_PUB_KEY_ECDSA
+    if is_pay_to_script_hash(public_key_bytes):
+        return SCRIPT_CLASS_SCRIPT_HASH
+    return SCRIPT_CLASS_NON_STANDARD
+
+
+def is_pay_to_pubkey(public_key_bytes):
+    if len(public_key_bytes) == 34 and \
+            public_key_bytes[0] == 0x20 and \
+            public_key_bytes[33] == 0xac:
+        return True
+    return False
+
+
+def is_pay_to_pubkey_ecdsa(public_key_bytes):
+    if len(public_key_bytes) == 35 and \
+            public_key_bytes[0] == 0x21 and \
+            public_key_bytes[34] == 0xab:
+        return True
+    return False
+
+
+def is_pay_to_script_hash(public_key_bytes):
+    if len(public_key_bytes) == 35 and \
+            public_key_bytes[0] == 0xaa and \
+            public_key_bytes[1] == 0x20 and \
+            public_key_bytes[34] == 0x87:
+        return True
+    return False