From f69a3aace48f0460bcca40518c818a7af7a9eb48 Mon Sep 17 00:00:00 2001
From: Floppyrj45 <claude@nowyouknow.fr>
Date: Fri, 24 Apr 2026 01:39:04 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20inspect=5Ftopics=20=E2=80=94=20liste=20?=
 =?UTF-8?q?tous=20les=20topics=20MCAP=20avec=20fr=C3=A9quences?=
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---
 extract/inspect_topics.py | 47 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 extract/inspect_topics.py

diff --git a/extract/inspect_topics.py b/extract/inspect_topics.py
new file mode 100644
index 0000000..88cecc4
--- /dev/null
+++ b/extract/inspect_topics.py
@@ -0,0 +1,47 @@
+import sys
+import glob
+from mcap.reader import make_reader
+
+class LargeRecordWrapper:
+    def __init__(self, fp):
+        self.fp = fp
+
+    def read(self, size=-1):
+        return self.fp.read(size)
+
+    def seek(self, pos, whence=0):
+        return self.fp.seek(pos, whence)
+
+    def tell(self):
+        return self.fp.tell()
+
+    def seekable(self):
+        return True
+
+def inspect(bag_dir: str):
+    files = sorted(glob.glob(f"{bag_dir}/*.mcap"))
+    if not files:
+        print(f"No MCAP files in {bag_dir}")
+        return
+    topics: dict[str, dict] = {}
+    for path in files:
+        try:
+            with open(path, "rb") as fp:
+                wrapped = LargeRecordWrapper(fp)
+                reader = make_reader(wrapped)
+                for schema, channel, message in reader.iter_messages():
+                    t = channel.topic
+                    if t not in topics:
+                        topics[t] = {"type": schema.name if schema else "?", "count": 0, "encoding": channel.message_encoding}
+                    topics[t]["count"] += 1
+        except Exception as e:
+            print(f"Warning: error reading {path}: {e}", file=sys.stderr)
+            continue
+
+    print(f"\n{'Topic':<50} {'Type':<45} {'Msgs':>6}")
+    print("-" * 105)
+    for t, info in sorted(topics.items()):
+        print(f"{t:<50} {info['type']:<45} {info['count']:>6}")
+
+if __name__ == "__main__":
+    inspect(sys.argv[1] if len(sys.argv) > 1 else "data/bags")