Kyuuhachi · April 7, 2024 15:21 · Dec 26, 2023 · Dec 26, 2023
diff --git a/nani.py b/nani.py
@@ -21,15 +21,10 @@ def decode(data: bytes) -> bytes:
 		return bytes(o)
 
 def fnhash(name: bytes) -> int:
-	v = 0
-	for i, b in enumerate(name):
-		v += (b - 32) * (1<<(i%5*5))
-	# There's gotta be a better way to do this...
-	v = (v & 0xFFFF) + (v >> 16) * 15
-	v = (v & 0xFFFF) + (v >> 16) * 15
-	v = (v & 0xFFFF) + (v >> 16) * 15
-	if v > 0xFFF0: v = (v + 0xF) & 0xFFFF
-	return v
+	return sum(
+		(b - 32) * (1<<(i%5*5))
+		for i, b in enumerate(name)
+	) % 0xFFF1
 
 def extract(na: bytes, ni: bytes, *, verify: bool = False) -> T.Iterator[tuple[str, bytes]]:
 	def take(a: bytes, n: int) -> tuple[bytes, bytes]: return a[:n], a[n:]

diff --git a/nani.py b/nani.py
@@ -0,0 +1,87 @@
+import typing as T
+from pathlib import Path
+import zlib
+import struct
+
+try:
+	import numpy as np
+	def decode(data: bytes) -> bytes:
+		data = np.frombuffer(data, dtype=np.ubyte).copy()
+		obf = 0x7C53F961 * 0x3D09 ** (1+np.arange(len(data), dtype=np.uint32))
+		data -= obf >> 16
+		return data.tobytes()
+except ImportError:
+	print("Could not import numpy — falling back to slow method")
+	def decode(data: bytes) -> bytes:
+		k = 0x7C53F961
+		o = bytearray()
+		for b in data:
+			k *= 0x3D09
+			o.append((b - (k >> 16)) & 0xFF)
+		return bytes(o)
+
+def fnhash(name: bytes) -> int:
+	v = 0
+	for i, b in enumerate(name):
+		v += (b - 32) * (1<<(i%5*5))
+	# There's gotta be a better way to do this...
+	v = (v & 0xFFFF) + (v >> 16) * 15
+	v = (v & 0xFFFF) + (v >> 16) * 15
+	v = (v & 0xFFFF) + (v >> 16) * 15
+	if v > 0xFFF0: v = (v + 0xF) & 0xFFFF
+	return v
+
+def extract(na: bytes, ni: bytes, *, verify: bool = False) -> T.Iterator[tuple[str, bytes]]:
+	def take(a: bytes, n: int) -> tuple[bytes, bytes]: return a[:n], a[n:]
+	head, ni = take(ni, 16)
+	head, p2, p3, p4 = struct.unpack("<4sIII", head)
+	assert head == b"NNI\0"
+	toc, ni = take(ni, p2*16)
+	names, ni = take(ni, p3)
+	assert p4 & 0x01 == 0, ".\\core\\nnk_file.cpp: vfs::Startup: No incremental linking support."
+	assert not ni
+
+	toc = decode(toc)
+	names = decode(names)
+
+	for hash, size, pos, namepos in struct.iter_unpack("<IIII", toc):
+		name = names[namepos:names.find(b"\0", namepos)]
+		if verify: assert hash == fnhash(name), name
+		name = name.decode("cp932").lower().replace("\\", "/")
+
+		if (pos, size) == (0, 0):
+			print(f"skipping blank file {name}")
+			continue
+
+		data = na[pos:pos+size]
+		if name.endswith(".z"):
+			name = name[:-2]
+			try:
+				checksum, usize = struct.unpack("<II", data[:8])
+				data = zlib.decompress(data[8:])
+				assert len(data) == usize
+				if verify: assert checksum == zlib.crc32(data)
+			except Exception:
+				print(f"failed to decompress {name}")
+				import traceback
+				traceback.print_exc()
+		yield name, data
+
+import argparse
+argp = argparse.ArgumentParser()
+argp.add_argument("-o", "--outdir", type=Path, required=True, dest="outdir")
+argp.add_argument("-v", "--verbose", action="store_true")
+argp.add_argument("-V", "--verify", action="store_true")
+argp.add_argument("files", nargs="+", type=Path)
+def __main__(outdir: Path, verbose: bool, verify: bool, files: list[Path]):
+	for path in files:
+		assert path.suffix in [".na", ".ni"], path
+		na = path.with_suffix(".na").read_bytes()
+		ni = path.with_suffix(".ni").read_bytes()
+		for name, data in extract(na, ni, verify=verify):
+			out = outdir / name
+			if verbose: print(out)
+			out.parent.mkdir(parents=True, exist_ok=True)
+			out.write_bytes(data)
+if __name__ == "__main__":
+	__main__(**argp.parse_args().__dict__)