1#!/usr/bin/env python 2import struct, sys 3 4 5""" 6Each timestamp field is an eight-byte value, first storing the time the 7file was loaded into the editor in DOS date/time format (see 8http://msdn.microsoft.com/en-us/library/ms724247(VS.85).aspx for details 9of this format), and then the length of time the file was loaded in the 10editor, in units of 1/18.2 second. (apparently this is fairly standard 11in DOS apps - I don't know) 12A new timestamp is written whenever the file is reloaded, but it is 13overwritten if the file is re-saved multiple times in the same editing 14session. 15 16Thanks to Saga Musix for finally figuring this crazy format out. 17""" 18 19for filename in sys.argv[1:]: 20 f = open(filename, 'rb') 21 if f.read(4) != 'IMPM'.encode('ascii'): 22 print("%s: not an IT file" % filename) 23 continue 24 f.seek(0x20) 25 ordnum, insnum, smpnum, patnum = struct.unpack('<4H', f.read(8)) 26 f.seek(0x2e) 27 special, = struct.unpack('<H', f.read(2)) 28 if not (special & 2): 29 print("%s: history flag not set (old IT version?)" % filename) 30 continue 31 para = [] 32 if special & 1: # message exists 33 f.seek(0x36) 34 msglen, msgoff = struct.unpack('<HL', f.read(6)) 35 if msglen: 36 para.append(msgoff) 37 f.seek(0xc0 + ordnum) 38 # we'll assume history is invalid if it ends after the first parapointer 39 para_count = insnum + smpnum + patnum 40 para.extend(struct.unpack('<%sL' % para_count, f.read(4 * para_count))) 41 hist, = struct.unpack('<H', f.read(2)) 42 hist_start = f.tell() 43 hist_len = hist_start + 8 * hist 44 try: 45 para_min = min(filter(None, para)) 46 except ValueError: 47 para_min = hist_len 48 # history entry count follows parapointers 49 if not hist: 50 print("%s: history missing (probably not saved with IT)" % filename) 51 continue 52 if para_min < hist_len: 53 print("%s: history data overlaps parapointers (malformed?)" % filename) 54 continue 55 histdata = f.read(8 * hist) 56 if len(histdata) != 8 * hist: 57 print("%s: history malformed (probably not saved by IT)" % filename) 58 continue 59 f.close() 60 print(filename) 61 totalticks = 0 62 def ticks2hms(ticks): 63 secs = ticks / 18.2 64 h, m, s = int(secs / 3600), int(secs / 60) % 60, int(secs) % 60 65 return ''.join([('%dh' % h if h else ''), ('%dm' % m if h or m else ''), ('%ds' % s)]) 66 for n in range(hist): 67 fatdate, fattime, ticks = struct.unpack('<HHL', histdata[8 * n : 8 * n + 8]) 68 day = fatdate & 31 69 month = (fatdate >> 5) & 15 70 year = (fatdate >> 9) + 1980 71 second = (fattime & 31) * 2 72 minute = (fattime >> 5) & 63 73 hour = fattime >> 11 74 print('\t%04d-%02d-%02d %02d:%02d:%02d %s' % (year, month, day, hour, minute, second, ticks2hms(ticks))) 75 totalticks += ticks 76 print("\t%13d ticks = %s" % (totalticks, ticks2hms(totalticks))) 77 78