How to convert le_nstime() to string in Lua

You're looking for format_date (or format_time), as in:

  -- First, convert the NSTime to a string (which yields a decimal number).
  -- Then, convert that string into a Lua number, required by format_date().
  local seconds = tostring(buf(offset,8):le_nstime())
  seconds = tonumber(seconds)
  value[i] = format_date(seconds)

But I should point out some other things about your sample code above:

1. There is no base.LOCAL (despite the documentation in the Wireshark user manual...this is a bug). Since it doesn't exist, base.LOCAL is equivalent to nil.

2. You don't need to initialize a table with zeroes. You can simply declare the table with empty brackets, and Lua is smart enough to know what to do when you index into the table with: value[i]. (Or maybe there's omitted code that actually checks these indices for zero...weird.)

   local value = {}

3. You don't need to convert the TvbRange into an NSTime when adding it to the tree because field_time is a ProtoField.absolute_time, which is inherently an NSTime. The endianness of the buffer is implied by TreeItem.add() and TreeItem.add_le() (you want add_le() in this case).

   local example_subtree = subtree:add_le(field_time, buf(offset,8));