i give up on can

2026/cscg/misc/can-i-have-flag/analyze_export.py

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+import csv
+
+# 1. Load the raw edges from the CSV
+edges = []
+with open('capture.csv', 'r') as f:
+    reader = csv.reader(f)
+    next(reader)  # Skip the header row
+    for row in reader:
+        # row[0] is time in seconds, row[1] is logic state (0 or 1)
+        edges.append((float(row[0]), int(row[1])))
+
+# 2. Reconstruct the physical bitstream (1 Mbps = 1 microsecond per bit)
+bit_time = 1e-6 
+bits = []
+
+for i in range(len(edges)-1):
+    duration = edges[i+1][0] - edges[i][0]
+    num_bits = int(round(duration / bit_time))
+    bits.extend([edges[i][1]] * num_bits)
+
+# 3. Parse the CAN frames directly (Ignoring Bit Stuffing Rules)
+idx = 0
+print("Hunting for payloads...\n")
+
+while idx < len(bits) - 50:
+    # Look for Start of Frame (0) after an idle bus (1)
+    if bits[idx] == 0 and (idx == 0 or bits[idx-1] == 1):
+        idx += 1  # Skip SOF
+        
+        id_bits = bits[idx : idx+11] # 11-bit ID
+        idx += 11
+        
+        idx += 3  # Skip RTR, IDE, and r0 control bits
+        
+        dlc_bits = bits[idx : idx+4] # 4-bit Data Length Code
+        dlc = int("".join(map(str, dlc_bits)), 2)
+        idx += 4
+        
+        # If payload exists, decode it into ASCII
+        if 0 < dlc <= 8:
+            payload = []
+            for _ in range(dlc):
+                byte_bits = bits[idx : idx+8]
+                byte_val = int("".join(map(str, byte_bits)), 2)
+                payload.append(chr(byte_val))
+                idx += 8
+            print(f"Decoded Payload: {''.join(payload)}")
+        else:
+            idx += 1 # Step forward if it was a false start
+    else:
+        idx += 1