Fix pathc collision entry lookups

src/pycrimson/_files/_pathc.py

@@ -90,9 +90,8 @@ def from_file(cls, path: Path):
             return cls(f)
 
     def get_file_header(self, path: str) -> bytes:
-        checksum = _crypto.calculate_checksum(
-            f"/{path}" if not path.startswith("/") else path
-        )
+        normalized_path = f"/{path}" if not path.startswith("/") else path
+        checksum = _crypto.calculate_checksum(normalized_path)
 
         entry = self._entries.get(checksum)
         assert entry is not None
@@ -101,7 +100,7 @@ def get_file_header(self, path: str) -> bytes:
             header = self._headers[entry.texture_header_index]
             compressed_block_infos = entry.compressed_block_infos
         else:
-            collision_entry = self._hash_collision_entries.get(path)
+            collision_entry = self._hash_collision_entries.get(normalized_path)
             assert collision_entry is not None
 
             header = self._headers[collision_entry.texture_header_index]

tests/test_pathc.py

@@ -0,0 +1,56 @@
+import unittest
+from types import SimpleNamespace
+
+from pycrimson._crypto import calculate_checksum
+from pycrimson._files._pathc import (
+    PackTextureHeaderCollection,
+    _PackTextureHeaderCollectionCollisionEntry,
+    _PackTextureHeaderCollectionEntry,
+)
+
+
+class TestPackTextureHeaderCollection(unittest.TestCase):
+    def _make_collection(self, normalized_path: str) -> PackTextureHeaderCollection:
+        checksum = calculate_checksum(normalized_path)
+
+        collection = PackTextureHeaderCollection.__new__(PackTextureHeaderCollection)
+        collection._header = SimpleNamespace(header_size=0x80)
+        collection._headers = [b"A" * 0x80, b"B" * 0x80]
+        collection._entries = {
+            checksum: _PackTextureHeaderCollectionEntry(
+                texture_header_index=0xFFFF,
+                collision_start_index=0,
+                collision_end_index=0,
+                compressed_block_infos=b"\x00" * 16,
+            )
+        }
+        collection._hash_collision_entries = {
+            normalized_path: _PackTextureHeaderCollectionCollisionEntry(
+                filename_offset=0,
+                texture_header_index=1,
+                unknown0=0,
+                compressed_block_infos=b"\x00" * 16,
+            )
+        }
+        return collection
+
+    def test_collision_lookup_normalizes_leading_slash(self):
+        path = "ui/texture/image/worldmap/cd_worldmap_road_sdf_32768x32768_6_8.dds"
+        normalized_path = f"/{path}"
+        collection = self._make_collection(normalized_path)
+
+        header = collection.get_file_header(path)
+
+        self.assertEqual(header, b"B" * 0x80)
+
+    def test_collision_lookup_accepts_already_normalized_path(self):
+        normalized_path = "/ui/texture/image/worldmap/cd_worldmap_road_sdf_32768x32768_6_8.dds"
+        collection = self._make_collection(normalized_path)
+
+        header = collection.get_file_header(normalized_path)
+
+        self.assertEqual(header, b"B" * 0x80)
+
+
+if __name__ == "__main__":
+    unittest.main()