Rehost selected-year bucket scalar ladder

tools/py/extract_selected_year_bucket_ladder.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import argparse
+import json
+import struct
+from pathlib import Path
+
+IMAGE_BASE = 0x400000
+PAIRED_YEAR_VALUE_TABLE_VA = 0x005F3980
+PAIR_COUNT = 21
+TERMINAL_SCALAR_VA = 0x005F3A24
+
+
+def read_u32_table(blob: bytes, va: int, count: int) -> list[int]:
+    offset = va - IMAGE_BASE
+    data = blob[offset : offset + count * 4]
+    if len(data) != count * 4:
+        raise ValueError(f"table at {va:#x} truncated")
+    return [struct.unpack("<I", data[i : i + 4])[0] for i in range(0, len(data), 4)]
+
+
+def build_artifact(exe_bytes: bytes) -> dict[str, object]:
+    raw_pairs = read_u32_table(exe_bytes, PAIRED_YEAR_VALUE_TABLE_VA, PAIR_COUNT * 2)
+    terminal_scalar_raw = read_u32_table(exe_bytes, TERMINAL_SCALAR_VA, 1)[0]
+    entries = []
+    for year, value in zip(raw_pairs[::2], raw_pairs[1::2]):
+        entries.append({"year": year, "value": float(value)})
+    return {
+        "source_kind": "rt3.exe-static-table",
+        "reader_family": "world_refresh_selected_year_bucket_scalar_band",
+        "table_virtual_address": f"0x{PAIRED_YEAR_VALUE_TABLE_VA:08x}",
+        "pair_count": PAIR_COUNT,
+        "terminal_scalar_virtual_address": f"0x{TERMINAL_SCALAR_VA:08x}",
+        "terminal_scalar_value": float(terminal_scalar_raw),
+        "entries": entries,
+    }
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(
+        description="Extract the selected-year bucket ladder used by RT3 world year refresh."
+    )
+    parser.add_argument("exe", type=Path, help="Path to RT3.exe")
+    parser.add_argument("output", type=Path, help="Output JSON path")
+    args = parser.parse_args()
+
+    artifact = build_artifact(args.exe.read_bytes())
+    args.output.write_text(json.dumps(artifact, indent=2) + "\n", encoding="utf-8")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())