add compat layer

draft_code/secp256k1.py

@@ -1,4 +1,4 @@
-import secp256k1
+import secp256k1_embedded
 import hashlib
 from binascii import hexlify
 

internal_filesystem/lib/secp256k1.py

@@ -3,6 +3,7 @@ import hashlib
 import binascii
 
 #from ._libsecp256k1 import ffi, lib
+from secp256k1_compat import ffi, lib  # Use compatibility layer
 
 
 EC_COMPRESSED = lib.SECP256K1_EC_COMPRESSED

internal_filesystem/lib/secp256k1_compat.py

@@ -0,0 +1,62 @@
+# secp256k1_compat.py: Compatibility layer for secp256k1.py to use MicroPython's usecp256k1 module
+# Mimics cffi's ffi and lib objects
+
+import usecp256k1  # Your MicroPython C module
+
+# Constants (from libsecp256k1)
+SECP256K1_CONTEXT_SIGN = 1 << 8  # 256
+SECP256K1_CONTEXT_VERIFY = 1 << 9  # 512
+SECP256K1_EC_COMPRESSED = 1 << 1  # 2
+SECP256K1_EC_UNCOMPRESSED = 0
+
+# Dummy ffi class to mimic cffi
+class FFI:
+    def new(self, type_str):
+        # For 'unsigned char[74]' or 'size_t *'
+        if 'unsigned char' in type_str:
+            size = int(type_str.split('[')[1].rstrip(']'))
+            return bytearray(size)
+        elif 'size_t *' in type_str:
+            return [0]  # Simulate pointer to size_t
+        raise ValueError(f"Unsupported ffi type: {type_str}")
+
+    def buffer(self, obj, size=None):
+        # Return bytes from bytearray or slice
+        if isinstance(obj, list):
+            return bytes(obj)
+        return bytes(obj[:size] if size is not None else obj)
+
+# Dummy lib class to map to usecp256k1 functions
+class Lib:
+    # Constants
+    SECP256K1_EC_COMPRESSED = SECP256K1_EC_COMPRESSED
+    SECP256K1_EC_UNCOMPRESSED = SECP256K1_EC_UNCOMPRESSED
+    SECP256K1_CONTEXT_SIGN = SECP256K1_CONTEXT_SIGN
+    SECP256K1_CONTEXT_VERIFY = SECP256K1_CONTEXT_VERIFY
+
+    def secp256k1_context_create(self, flags):
+        # Context is managed by usecp256k1, return dummy object
+        return object()
+
+    def secp256k1_ecdsa_signature_serialize_der(self, ctx, output, outputlen, raw_sig):
+        # Call usecp256k1_ecdsa_signature_serialize_der
+        try:
+            result = usecp256k1.usecp256k1_ecdsa_signature_serialize_der(raw_sig)
+            if result is None:
+                return 0  # Mimic libsecp256k1 failure
+            # Copy result to output buffer
+            output[:len(result)] = result
+            outputlen[0] = len(result)
+            return 1  # Mimic libsecp256k1 success
+        except ValueError:
+            return 0  # Handle errors like invalid signature length
+
+# Instantiate ffi and lib
+ffi = FFI()
+lib = Lib()
+
+# Feature flags (set based on your usecp256k1 module's capabilities)
+HAS_RECOVERABLE = hasattr(usecp256k1, 'usecp256k1_ecdsa_sign_recoverable')
+HAS_SCHNORR = hasattr(usecp256k1, 'usecp256k1_schnorrsig_sign')
+HAS_ECDH = hasattr(usecp256k1, 'usecp256k1_ecdh')
+HAS_EXTRAKEYS = hasattr(usecp256k1, 'usecp256k1_keypair_create')