SoE: implement everything else

worlds/soe/Patch.py

@@ -0,0 +1,52 @@
+import bsdiff4
+import yaml
+from typing import Optional
+import Utils
+
+
+def read_rom(stream, strip_header=True) -> bytes:
+    """Reads rom into bytearray and optionally strips off any smc header"""
+    data = stream.read()
+    if strip_header and len(data) % 0x400 == 0x200:
+        return data[0x200:]
+    return data
+
+
+def generate_yaml(patch: bytes, metadata: Optional[dict] = None) -> bytes:
+    patch = yaml.dump({"meta": metadata,
+                       "patch": patch,
+                       "game": "Secret of Evermore",
+                       # minimum version of patch system expected for patching to be successful
+                       "compatible_version": 1,
+                       "version": 1})
+    return patch.encode(encoding="utf-8-sig")
+
+
+def generate_patch(vanilla_file, randomized_file, metadata: Optional[dict] = None) -> bytes:
+    with open(vanilla_file, "rb") as f:
+        vanilla = read_rom(f)
+    with open(randomized_file, "rb") as f:
+        randomized = read_rom(f)
+    if metadata is None:
+        metadata = {}
+    patch = bsdiff4.diff(vanilla, randomized)
+    return generate_yaml(patch, metadata)
+
+
+if __name__ == '__main__':
+    import argparse
+    import pathlib
+    import lzma
+    parser = argparse.ArgumentParser(description='Apply patch to Secret of Evermore.')
+    parser.add_argument('patch', type=pathlib.Path, help='path to .absoe file')
+    args = parser.parse_args()
+    with open(args.patch, "rb") as f:
+        data = Utils.parse_yaml(lzma.decompress(f.read()).decode("utf-8-sig"))
+    if data['game'] != 'Secret of Evermore':
+        raise RuntimeError('Patch is not for Secret of Evermore')
+    with open(Utils.get_options()['soe_options']['rom_file'], 'rb') as f:
+        vanilla_data = read_rom(f)
+    patched_data = bsdiff4.patch(vanilla_data, data["patch"])
+    with open(args.patch.parent / (args.patch.stem + '.sfc'), 'wb') as f:
+        f.write(patched_data)
+