Updated README to include Digests

---

+ remove unnecessary mode checks in digest verification

README.md

@@ -40,15 +40,20 @@ class Format:
     b: int32
     length: uint8             # String fields with computed lengths
     name: String(this.length) #  -> you can also use Prefixed(uint8)
-    names: CString[uint8::]   # Sequences with prefixed, computed lengths
+    with Md5(name="hash", verify=True): # wraps all following fields and creates a new attr
+        names: CString[uint8::]    # Sequences with prefixed, computed lengths
+
 
 # Instantiation (keyword-only arguments, magic is auto-inferred):
 obj = Format(a=1, b=2, length=3, name="foo", names=["a", "b"])
-# Packing the object:
-blob = pack(obj) # objects of struct classes can be packed right away
-# results in: b'ITS MAGIC\x01\x02\x00\x00\x00\x03foo\x02a\x00b\x00'
-# Unpacking the binary data:
-obj2 = unpack(blob, Format)
+# Packing the object, reads as 'PACK obj FROM Format'
+# objects of struct classes can be packed right away
+blob = pack(obj, Format)
+# results in: b'ITS MAGIC\x01\x02\x00\x00\x00\x03foo\x02a\x00b\x00\xf55...
+
+# Unpacking the binary data, reads as 'UNPACK Format FROM blob'
+obj2 = unpack(Format, blob)
+assert obj2.hash == obj.hash
 ```
 
 This library offers extensive functionality beyond basic struct handling. For further details

src/caterpillar/fields/__init__.py

@@ -53,7 +53,7 @@
     Uuid,
     Aligned,
     align,
-    Lazy
+    Lazy,
 )
 from .varint import VarInt, VARINT_LSB, vint
 from .compression import (
@@ -68,4 +68,20 @@
 from .pointer import uintptr, intptr, offintptr, offuintptr, Pointer
 from .conditional import ConditionalChain, If, Else, ElseIf
 from .hook import IOHook
-from .digest import Digest, Algorithm
+from .digest import (
+    Digest,
+    Algorithm,
+    Md5,
+    Sha1,
+    Sha2_256,
+    Sha2_224,
+    Sha2_384,
+    Sha2_512,
+    Sha3_224,
+    Sha3_256,
+    Sha3_384,
+    Sha3_512,
+    Crc32,
+    Adler,
+    HMAC
+)

src/caterpillar/fields/digest.py

@@ -384,10 +384,6 @@ def verfiy(self, context: _ContextLike) -> None:
         :raises ValidationError: If the digest verification fails.
         """
         # we assume self._verify is True
-        if context._root.mode == MODE_PACK:
-            # we don'T verify in packing mode as we created that digest
-            return
-
         digest = context.__context_getattr__(self.path or self.name)
         if digest != self._digest:
             digest_raw = digest.hex() if isinstance(digest, bytes) else digest
@@ -491,11 +487,7 @@ def _cryptography_hash_algo(cls: Type[hashes.HashAlgorithm]):
     Sha3_256_Algo = _cryptography_hash_algo(hashes.SHA3_256)
     Sha3_384_Algo = _cryptography_hash_algo(hashes.SHA3_384)
     Sha3_512_Algo = _cryptography_hash_algo(hashes.SHA3_512)
-
     Md5_Algo = _cryptography_hash_algo(hashes.MD5)
-    Blake2b_Algo = _cryptography_hash_algo(hashes.BLAKE2b)
-    Blake2s_Algo = _cryptography_hash_algo(hashes.BLAKE2s)
-    Sm3_Algo = _cryptography_hash_algo(hashes.SM3)
 
     Sha1 = _hash_digest(Sha1_Algo, Bytes(20))
     Sha2_224 = _hash_digest(Sha2_224_Algo, Bytes(28))