Initial commit

src/dataset/class_mapping.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+
+CLASS_WITH_ID_RE = re.compile(r"^\s*(?P<class_id>\d+(?:\.0+)?)\s+(?P<class_name>.+?)\s*$")
+
+
+def parse_predefined_classes(path: Path) -> dict[int, str]:
+    """Parse predefined_classes.txt in either indexed or line-only format."""
+    mapping: dict[int, str] = {}
+    next_index = 0
+
+    for raw_line in path.read_text(encoding="utf-8", errors="ignore").splitlines():
+        line = raw_line.strip()
+        if not line:
+            continue
+
+        match = CLASS_WITH_ID_RE.match(line)
+        if match:
+            class_id = int(float(match.group("class_id")))
+            class_name = match.group("class_name").strip()
+        else:
+            class_id = next_index
+            class_name = line
+
+        mapping[class_id] = class_name
+        next_index = max(next_index, class_id + 1)
+
+    return mapping
+
+
+def mapping_signature(mapping: dict[int, str]) -> tuple[tuple[int, str], ...]:
+    """Return a hashable signature for a class mapping."""
+    return tuple(sorted(mapping.items()))
+
+
+def normalize_mapping_for_json(mapping: dict[int, str]) -> dict[str, str]:
+    """Convert class mapping keys to strings for JSON serialization."""
+    return {str(class_id): class_name for class_id, class_name in sorted(mapping.items())}