WAD header reading, offset calculation for partitions

Currently untested.

src/libWiiPy/wad.py

@@ -0,0 +1,102 @@
+# Project: libWiiPy by NinjaCheetah
+# File: wad.py by rmc
+#
+# See https://wiibrew.org/wiki/WAD_files for details about the WAD format
+
+import binascii
+from dataclasses import dataclass
+from typing import List
+
+
+@dataclass
+class ContentRecord:
+    """Creates a content record object that contains the details of a content contained in a title."""
+    cid: int  # Content ID
+    index: int  # Index in the list of contents
+    content_type: int  # normal: 0x0001; dlc: 0x4001; shared: 0x8001
+    content_size: int
+    content_hash: bytearray  # SHA1 hash content
+
+
+class wadHeader:
+    """Break down 32 byte WAD header."""
+    def __init__(self, wadhdr):
+        self.wadhdr = wadhdr
+        self.wad_hdr_size: int
+        self.wad_type: int
+        self.wad_version: int
+        # Sizes
+        self.wad_cert_size: int
+        self.wad_crl_size: int
+        self.wad_tik_size: int
+        self.wad_tmd_size: int
+        self.wad_app_size: int  # Note that this is the size of the app region. This is each individual app file bundled together.
+        self.wad_meta_size: int
+        # Offsets
+        self.wad_cert_offset: int
+        self.wad_crl_offset: int
+        self.wad_tik_offset: int
+        self.wad_tmd_offset: int
+        self.wad_app_offset: int
+        self.wad_meta_offset: int
+        #self.content_record: List[ContentRecord]
+        # Load header data from WAD file
+        with open(wad, "rb") as wadfile:
+            #====================================================================================
+            # Get the sizes of each data region contained within the WAD. Sorry for mid code!
+            #====================================================================================
+            # Header length. Always seems to be 32 so we'll ignore it for now.
+            wadfile.seek(0x0)
+            self.wad_hdr_size = wadfile.read(4)
+            # WAD type
+            wadfile.seek(0x04)
+            self.wad_type = wadfile.read(2)
+            # WAD version
+            wadfile.seek(0x06)
+            self.wad_version = wadfile.read(2)
+            # WAD cert size
+            wadfile.seek(0x08)
+            self.wad_cert_size = wadfile.read(4)
+            # WAD crl size
+            wadfile.seek(0x0c)
+            self.wad_crl_size = wadfile.read(4)
+            # WAD ticket size
+            wadfile.seek(0x10)
+            self.wad_tik_size = wadfile.read(4)
+            # WAD TMD size
+            wadfile.seek(0x14)
+            self.wad_tmd_size = wadfile.read(4)
+            # WAD app size
+            wadfile.seek(0x18)
+            self.wad_app_size = wadfile.read(4)
+            # Publisher of the title
+            wadfile.seek(0x1c)
+            self.wad_meta_size = wadfile.read(4)
+            #====================================================================================
+            # Calculate file offsets from sizes
+            #====================================================================================
+            self.wad_cert_offset + self.wad_hdr_size
+            # I've never seen crl used (don't even know what it's for) but still calculating in case...
+            self.wad_crl_offset + self.wad_cert_offset + self.wad_cert_size
+            self.wad_tik_offset + self.wad_crl_offset + self.wad_crl_size
+            self.wad_tmd_offset + self.wad_tik_offset + self.wad_tik_size
+            self.wad_app_offset + self.wad_tmd_offset + self.wad_tmd_size
+            # Same with meta. If private Nintendo tools calculate these then maaaaaybe we should too.
+            self.wad_meta_offset + self.wad_app_offset + self.wad_app_size
+
+    def get_cert_region(self):
+        """Returns the offset and size for the cert"""
+        return self.wad_cert_offset, self.wad_cert_size
+
+    def get_ticket_region(self):
+        """Returns the offset and size for the ticket"""
+        return self.wad_tik_offset, self.wad_tik_size
+
+    def get_tmd_region(self):
+        """Returns the offset and size for the TMD"""
+        return self.wad_tmd_offset, self.wad_tmd_size
+
+    def get_app_region(self):
+        """Returns the offset and size for the app"""
+        return self.wad_app_offset, self.wad_tmd_size
+