load_library: remove ctypes.util.find_library calls. remove some code dupe

find_library was giving priority to system dll against local dll

lib/ecc.py

@@ -109,13 +109,7 @@ def ser_to_point(ser: bytes) -> (int, int):
 
 
 def _ser_to_python_ecdsa_point(ser: bytes) -> ecdsa.ellipticcurve.Point:
-    if ser[0] not in (0x02, 0x03, 0x04):
+    x, y = ser_to_point(ser)
-        raise ValueError('Unexpected first byte: {}'.format(ser[0]))
-    x = string_to_number(ser[1:33])
-    if ser[0] == 0x04:
-        y = string_to_number(ser[33:])
-    else:
-        y = get_y_coord_from_x(x, ser[0] == 0x03)
     return Point(curve_secp256k1, x, y, CURVE_ORDER)
 
 

lib/ecc_fast.py

@@ -32,18 +32,13 @@ SECP256K1_EC_COMPRESSED = (SECP256K1_FLAGS_TYPE_COMPRESSION | SECP256K1_FLAGS_BI
 SECP256K1_EC_UNCOMPRESSED = (SECP256K1_FLAGS_TYPE_COMPRESSION)
 
 
-# TODO double check ctypes arg/return value types against https://github.com/bitcoin-core/secp256k1/blob/master/src/secp256k1.c
 def load_library():
-    library_path = ctypes.util.find_library('libsecp256k1') or \
+    if sys.platform == 'darwin':
-                   ctypes.util.find_library('secp256k1')
+        library_path = 'libsecp256k1.dylib'
-    if not library_path:
+    elif sys.platform in ('windows', 'win32'):
-        print_error('[ecc] info: libsecp256k1 library was not found, trying fallback name')
+        library_path = 'libsecp256k1.dll'
-        if sys.platform == 'darwin':
+    else:
-            library_path = 'libsecp256k1.dylib'
+        library_path = 'libsecp256k1.so.0'
-        elif sys.platform in ('windows', 'win32'):
-            library_path = 'libsecp256k1.dll'
-        else:
-            library_path = 'libsecp256k1.so.0'
 
     secp256k1 = ctypes.cdll.LoadLibrary(library_path)
     if not secp256k1: