Fix #4

src/libretro/api/_utils.py

@@ -129,7 +129,7 @@ def addressof_buffer(buffer: Buffer) -> int:
 
 
 def memoryview_at(
-    address: c_char_p | c_void_p | int, size: c_ssize_t | int, readonly=False
+    address: c_char_p | c_void_p | int | bytes, size: c_ssize_t | int, readonly=False
 ) -> memoryview:
     flags = c_int(0x100 if readonly else 0x200)
     return pythonapi.PyMemoryView_FromMemory(cast(address, c_char_p), c_ssize_t(size), flags)

src/libretro/core.py

@@ -513,7 +513,13 @@ def unserialize(self, data: bytes | bytearray | memoryview | Buffer) -> bool:
         """
         buf: memoryview
         match data:
-            case bytes() | bytearray() | Buffer():
+            case bytes():
+                buf = memoryview_at(data, len(data), readonly=False)
+                # HACK! ctypes.Array.from_buffer requires a writable buffer,
+                # but bytes objects are read-only.
+                # retro_unserialize isn't supposed to modify the buffer,
+                # so we can blame undefined behavior if the core tries to write to it anyway.
+            case bytearray() | Buffer():
                 buf = memoryview(data)
             case memoryview():
                 buf = data
@@ -525,6 +531,7 @@ def unserialize(self, data: bytes | bytearray | memoryview | Buffer) -> bool:
         buflen = len(buf)
         arraytype: Array = c_char * buflen
 
+        # TODO: Validate that the buffer wasn't written to, and raise a warning if it was. (Use zlib.crc32)
         return self._core.retro_unserialize(byref(arraytype.from_buffer(buf)), buflen)
 
     def cheat_reset(self):