base_encode/base_decode: change to saner API

electrum/bitcoin.py

@@ -328,7 +328,7 @@ def hash160_to_b58_address(h160: bytes, addrtype: int) -> str:
 
 def b58_address_to_hash160(addr: str) -> Tuple[int, bytes]:
     addr = to_bytes(addr, 'ascii')
-    _bytes = base_decode(addr, 25, base=58)
+    _bytes = base_decode(addr, base=58, length=25)
     return _bytes[0], _bytes[1:21]
 
 
@@ -446,7 +446,7 @@ __b43chars = b'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ$*+-./:'
 assert len(__b43chars) == 43
 
 
-def base_encode(v: bytes, base: int) -> str:
+def base_encode(v: bytes, *, base: int) -> str:
     """ encode v, which is a string of bytes, to base58."""
     assert_bytes(v)
     if base not in (58, 43):
@@ -479,7 +479,7 @@ def base_encode(v: bytes, base: int) -> str:
     return result.decode('ascii')
 
 
-def base_decode(v: Union[bytes, str], length: Optional[int], base: int) -> Optional[bytes]:
+def base_decode(v: Union[bytes, str], *, base: int, length: int = None) -> Optional[bytes]:
     """ decode v into a string of len bytes."""
     # assert_bytes(v)
     v = to_bytes(v, 'ascii')
@@ -526,7 +526,7 @@ def EncodeBase58Check(vchIn: bytes) -> str:
 
 
 def DecodeBase58Check(psz: Union[bytes, str]) -> bytes:
-    vchRet = base_decode(psz, None, base=58)
+    vchRet = base_decode(psz, base=58)
     payload = vchRet[0:-4]
     csum_found = vchRet[-4:]
     csum_calculated = sha256d(payload)[0:4]

electrum/tests/test_bitcoin.py

@@ -764,20 +764,20 @@ class TestBaseEncode(ElectrumTestCase):
     def test_base43(self):
         tx_hex = "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"
         tx_bytes = bfh(tx_hex)
-        tx_base43 = base_encode(tx_bytes, 43)
+        tx_base43 = base_encode(tx_bytes, base=43)
         self.assertEqual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
                          tx_base43)
         self.assertEqual(tx_bytes,
-                         base_decode(tx_base43, None, 43))
+                         base_decode(tx_base43, base=43))
 
     def test_base58(self):
         data_hex = '0cd394bef396200774544c58a5be0189f3ceb6a41c8da023b099ce547dd4d8071ed6ed647259fba8c26382edbf5165dfd2404e7a8885d88437db16947a116e451a5d1325e3fd075f9d370120d2ab537af69f32e74fc0ba53aaaa637752964b3ac95cfea7'
         data_bytes = bfh(data_hex)
-        data_base58 = base_encode(data_bytes, 58)
+        data_base58 = base_encode(data_bytes, base=58)
         self.assertEqual("VuvZ2K5UEcXCVcogny7NH4Evd9UfeYipsTdWuU4jLDhyaESijKtrGWZTFzVZJPjaoC9jFBs3SFtarhDhQhAxkXosUD8PmUb5UXW1tafcoPiCp8jHy7Fe2CUPXAbYuMvAyrkocbe6",
                          data_base58)
         self.assertEqual(data_bytes,
-                         base_decode(data_base58, None, 58))
+                         base_decode(data_base58, base=58))
 
     def test_base58check(self):
         data_hex = '0cd394bef396200774544c58a5be0189f3ceb6a41c8da023b099ce547dd4d8071ed6ed647259fba8c26382edbf5165dfd2404e7a8885d88437db16947a116e451a5d1325e3fd075f9d370120d2ab537af69f32e74fc0ba53aaaa637752964b3ac95cfea7'

electrum/transaction.py

@@ -907,7 +907,7 @@ def convert_raw_tx_to_hex(raw: Union[str, bytes]) -> str:
         pass
     # try base43
     try:
-        return base_decode(raw, length=None, base=43).hex()
+        return base_decode(raw, base=43).hex()
     except:
         pass
     # try base64

electrum/util.py

@@ -846,7 +846,7 @@ def parse_URI(uri: str, on_pr: Callable = None, *, loop=None) -> dict:
             raise InvalidBitcoinURI(f"failed to parse 'exp' field: {repr(e)}") from e
     if 'sig' in out:
         try:
-            out['sig'] = bh2u(bitcoin.base_decode(out['sig'], None, base=58))
+            out['sig'] = bh2u(bitcoin.base_decode(out['sig'], base=58))
         except Exception as e:
             raise InvalidBitcoinURI(f"failed to parse 'sig' field: {repr(e)}") from e