New bitfield concept based in int.{from,to}_bytes

---

+ BitField was renamed to Bitfield
+ Each Bitfield now stores a list of groups, which either represent a field or a list of entries
+ bitfield_example was updated

Author: MatrixEditor

examples/bitfield_example.py

@@ -1,4 +1,5 @@
 # type: ignore
+from caterpillar.fields.common import uint8
 from caterpillar.py import bitfield, char, int8, unpack, pack
 
 try:
@@ -16,10 +17,10 @@ class Format:
     _1: 3  # unnamed padding to the rest of the byte
 
 
-print(Format.__struct__)
+print(Format.__struct__.groups)
 obj = unpack(Format, b"\x80\x80")
 print(obj)
-# prints: Format(b1=True, b2='2', b3=0, _1=0)
+# prints: Format(b1=1, b2='2', b3=0, _1=0)
 # real_pos:      0123456701234567
 # bit_pos:       7654321076543210
 #                ---------------- # right to left

src/caterpillar/model/__init__.py

@@ -25,7 +25,18 @@
     pack_file,
     sizeof,
 )
-from ._bitfield import BitField, bitfield, BitFieldGroup, issigned, getbits
+from ._bitfield import (
+    Bitfield,
+    bitfield,
+    BitfieldEntry,
+    BitfieldGroup,
+    BitfieldValueFactory,
+    issigned,
+    getbits,
+    NewGroup,
+    EndGroup,
+    SetAlignment,
+)
 from ._template import istemplate, template, TemplateTypeVar, derive
 
 __all__ = [
@@ -40,13 +51,18 @@
     "pack_into",
     "pack_file",
     "sizeof",
-    "BitField",
+    "Bitfield",
     "bitfield",
-    "BitFieldGroup",
+    "BitfieldGroup",
     "issigned",
     "getbits",
     "istemplate",
     "template",
     "TemplateTypeVar",
     "derive",
+    "NewGroup",
+    "EndGroup",
+    "SetAlignment",
+    "BitfieldEntry",
+    "BitfieldValueFactory",
 ]

src/caterpillar/model/_base.py

@@ -424,7 +424,7 @@ def pack_one(self, obj, context) -> None:
                 if name in self._member_map_:
                     value = self.get_value(obj, name, field)
                 else:
-                    # REVISIT: this line might not be necessary if const fields alredy
+                    # REVISIT: this line might not be necessary if const fields already
                     # use their internal value.
                     value = field.default if field.default != INVALID_DEFAULT else None
                 field.__pack__(value, context)

src/caterpillar/model/_base.pyi

@@ -32,6 +32,7 @@ class Sequence(FieldMixin, Generic[_SeqModelT], _StructLike[_SeqModelT, _SeqMode
     options: set[Flag]
     field_options: set[Flag]
     is_union: bool
+    _member_map_: Dict[str, Field]
     def __init__(
         self,
         model: Optional[dict[str, Field]] = None,