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Message ID: 235     Entry time: 23 Nov 2005
Author: Stefan Ritt 
Topic: Bug Fix 
Subject: Endian swapping in mana.c 
It was reported that following code in mana.c :
  /* swap event header if in wrong format */
  if (pevent->serial_number > 0x1000000) {
     WORD_SWAP(&pevent->event_id);
     WORD_SWAP(&pevent->trigger_mask);
     DWORD_SWAP(&pevent->serial_number);
     DWORD_SWAP(&pevent->time_stamp);
     DWORD_SWAP(&pevent->data_size);
  }

does not work correctly for events having a true serial number above 16777216 (=0x10000000). After some considerations, I concluded that there is no good way to determine automatically the endian format of midas events, without adding another field in the header, which would break the compatibility with all recorded data up to date. I therefore changed the above code to
  /* swap event header if in wrong format */
#ifdef SWAP_EVENTS
  WORD_SWAP(&pevent->event_id);
  WORD_SWAP(&pevent->trigger_mask);
  DWORD_SWAP(&pevent->serial_number);
  DWORD_SWAP(&pevent->time_stamp);
  DWORD_SWAP(&pevent->data_size);
#endif

So if one wants to analyze events with the midas analyzer on a PC system for example where the events come from a VxWorks system with the opposite endian encoding, one has to set the flag -DSWAP_EVENTS when compiling the analyzer for that type of analysis.
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