feat: add basic support for struct definition through c code

Author: MrIndeciso

libdestruct/c/struct_parser.py

@@ -0,0 +1,80 @@
+#
+# This file is part of libdestruct (https://github.com/mrindeciso/libdestruct).
+# Copyright (c) 2024 Roberto Alessandro Bertolini. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for details.
+#
+
+from __future__ import annotations
+
+import ctypes
+from typing import TYPE_CHECKING
+
+from pycparser import c_ast, c_parser
+
+from libdestruct.common.struct import struct
+
+if TYPE_CHECKING:
+    from libdestruct.common.obj import obj
+
+
+def definition_to_type(definition: str) -> type[obj]:
+    """Converts a C struct definition to a struct object."""
+    parser = c_parser.CParser()
+
+    ast = parser.parse(definition)
+
+    if len(ast.ext) != 1:
+        raise ValueError("Definition must contain exactly one top object.")
+
+    root = ast.ext[0].type
+
+    if not isinstance(root, c_ast.Struct):
+        raise TypeError("Definition must be a struct.")
+
+    return struct_to_type(root)
+
+
+def struct_to_type(struct_node: c_ast.Struct) -> type[struct]:
+    """Converts a C struct to a struct object."""
+    if not isinstance(struct_node, c_ast.Struct):
+        raise TypeError("Definition must be a struct.")
+
+    fields = {}
+
+    for decl in struct_node.decls:
+        name = decl.name
+        typ = type_decl_to_type(decl.type)
+        fields[name] = typ
+
+    type_name = struct_node.name if struct_node.name else "anon_struct"
+
+    return type(type_name, (struct,), {"__annotations__": fields})
+
+
+def type_decl_to_type(decl: c_ast.TypeDecl) -> type[obj]:
+    """Converts a C type declaration to a type."""
+    if not isinstance(decl, c_ast.TypeDecl):
+        raise TypeError("Definition must be a type declaration.")
+
+    if isinstance(decl.type, c_ast.Struct):
+        return struct_to_type(decl.type)
+
+    if isinstance(decl.type, c_ast.IdentifierType):
+        return identifier_to_type(decl.type)
+
+    raise TypeError("Unsupported type.")
+
+
+def identifier_to_type(identifier: c_ast.IdentifierType) -> type[obj]:
+    """Converts a C identifier to a type."""
+    if not isinstance(identifier, c_ast.IdentifierType):
+        raise TypeError("Definition must be an identifier.")
+
+    identifier_name = "_".join(identifier.names)
+
+    ctypes_name = f"c_{identifier_name}"
+
+    if hasattr(ctypes, ctypes_name):
+        return getattr(ctypes, ctypes_name)
+
+    raise ValueError(f"Unsupported identifier: {identifier_name}.")

pyproject.toml

@@ -29,7 +29,7 @@ classifiers = [
     "Typing :: Typed",
 ]
 keywords = ["struct", "c", "debugger", "memory", "reverse", "rev", "reverse-engineering", "script", "libdebug"]
-dependencies = ["typing_extensions"]
+dependencies = ["typing_extensions", "pycparser"]
 
 [project.optional-dependencies]
 dev = [