I’m wondering if it is possible to split BLF-files in Python? I know that there is a library (can) that supports BLF-files, but find no documentation on how to split/save. I can read a BLF-file with:
import can log = can.BLFReader("logfile.blf")
Would appreciate any help if anybody has knowledge in how I would split this file, and save it into smaller blf-files.
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Answer
You can read your logfile and write all messages to new files, changing file every N messages (in my example N=100, which is very low). I find it very useful to look at the doc, otherwise I wouldn’t know how to resume iteration over log_in
(in this case as a generator) or how to easily get object_count
:
import can OUTPUT_MAX_SIZE = 100 with open("blf_file.blf", 'rb') as f_in: log_in = can.io.BLFReader(f_in) log_in_iter = log_in.__iter__() object_count = log_in.object_count i = 0 while i*OUTPUT_MAX_SIZE < object_count: i += 1 with open(f"smaller_file{i}.blf", 'wb') as f_out: log_out = can.io.BLFWriter(f_out) j = 0 while j < OUTPUT_MAX_SIZE: log_out.on_message_received(log_in_iter.__next__()) j += 1 log_out.stop()