bitcoin.py: SCRIPT-related clean-up. transaction.py: construct_witness

lib/bitcoin.py

@@ -152,7 +152,7 @@ def int_to_hex(i, length=1):
     s = "0"*(2*length - len(s)) + s
     return rev_hex(s)
 
-def script_num_to_hex(i):
+def script_num_to_hex(i: int) -> str:
     """See CScriptNum in Bitcoin Core.
     Encodes an integer as hex, to be used in script.
 
@@ -176,7 +176,7 @@ def script_num_to_hex(i):
     return bh2u(result)
 
 
-def var_int(i):
+def var_int(i: int) -> str:
     # https://en.bitcoin.it/wiki/Protocol_specification#Variable_length_integer
     if i<0xfd:
         return int_to_hex(i)
@@ -188,14 +188,14 @@ def var_int(i):
         return "ff"+int_to_hex(i,8)
 
 
-def witness_push(item):
-    """ Returns data in the form it should be present in the witness.
+def witness_push(item: str) -> str:
+    """Returns data in the form it should be present in the witness.
     hex -> hex
     """
     return var_int(len(item) // 2) + item
 
 
-def op_push(i):
+def op_push(i: int) -> str:
     if i<0x4c:  # OP_PUSHDATA1
         return int_to_hex(i)
     elif i<=0xff:
@@ -206,37 +206,33 @@ def op_push(i):
         return '4e' + int_to_hex(i,4)
 
 
-def add_data_to_script(data):
+def push_script(data: str) -> str:
     """Returns pushed data to the script, automatically
     choosing canonical opcodes depending on the length of the data.
-    bytes -> bytes
+    hex -> hex
 
     ported from https://github.com/btcsuite/btcd/blob/fdc2bc867bda6b351191b5872d2da8270df00d13/txscript/scriptbuilder.go#L128
     """
-    assert_bytes(data)
+    data = bfh(data)
     from .transaction import opcodes
 
     data_len = len(data)
 
     # "small integer" opcodes
     if data_len == 0 or data_len == 1 and data[0] == 0:
-        return bytes([opcodes.OP_0])
+        return bh2u(bytes([opcodes.OP_0]))
     elif data_len == 1 and data[0] <= 16:
-        return bytes([opcodes.OP_1 - 1 + data[0]])
+        return bh2u(bytes([opcodes.OP_1 - 1 + data[0]]))
     elif data_len == 1 and data[0] == 0x81:
-        return bytes([opcodes.OP_1NEGATE])
+        return bh2u(bytes([opcodes.OP_1NEGATE]))
 
-    return bfh(push_script(bh2u(data)))
+    return op_push(data_len) + bh2u(data)
 
 
-def add_number_to_script(i):
-    """int -> bytes"""
-    return add_data_to_script(bfh(script_num_to_hex(i)))
+def add_number_to_script(i: int) -> bytes:
+    return bfh(push_script(script_num_to_hex(i)))
 
 
-def push_script(x):
-    return op_push(len(x)//2) + x
-
 def sha256(x):
     x = to_bytes(x, 'utf8')
     return bytes(hashlib.sha256(x).digest())