#!/usr/bin/python

# Written by Antonio Galea - 2010年11月18日
# Updated for DFU 1.1 by Sean Cross - 2020年03月31日
# Distributed under Gnu LGPL 3.0
# see http://www.gnu.org/licenses/lgpl-3.0.txt

import sys,struct,zlib,os
from optparse import OptionParser

DEFAULT_DEVICE="0x0483:0xdf11"

def named(tuple,names):
 return dict(zip(names.split(),tuple))
def consume(fmt,data,names):
 n = struct.calcsize(fmt)
 return named(struct.unpack(fmt,data[:n]),names),data[n:]
def cstring(string):
 return string.split('0円',1)[0]
def compute_crc(data):
 return 0xFFFFFFFF & -zlib.crc32(data) -1

def parse(file,dump_images=False):
 print ('File: "%s"' % file)
 data = open(file,'rb').read()
 crc = compute_crc(data[:-4])
 data = data[len(data)-16:]
 suffix = named(struct.unpack('<4H3sBI',data[:16]),'device product vendor dfu ufd len crc')
 print ('usb: %(vendor)04x:%(product)04x, device: 0x%(device)04x, dfu: 0x%(dfu)04x, %(ufd)s, %(len)d, 0x%(crc)08x' % suffix)
 if crc != suffix['crc']:
 print ("CRC ERROR: computed crc32 is 0x%08x" % crc)
 data = data[16:]
 if data:
 print ("PARSE ERROR")

def build(file,data,device=DEFAULT_DEVICE):
 # Parse the VID and PID from the `device` argument
 v,d=map(lambda x: int(x,0) & 0xFFFF, device.split(':',1))

 # Generate the DFU suffix, consisting of these fields:
 # Field name | Length | Description
 # ================+=========+================================
 # bcdDevice | 2 | The release number of this firmware (0xffff - don't care)
 # idProduct | 2 | PID of this device
 # idVendor | 2 | VID of this device
 # bcdDFU | 2 | Version of this DFU spec (0x01 0x00)
 # ucDfuSignature | 3 | The characters 'DFU', printed in reverse order
 # bLength | 1 | The length of this suffix (16 bytes)
 # dwCRC | 4 | A CRC32 of the data, including this suffix
 data += struct.pack('<4H3sB',0xffff,d,v,0x0100,b'UFD',16)
 crc = compute_crc(data)
 # Append the CRC32 of the entire block
 data += struct.pack('<I',crc)
 open(file,'wb').write(data)

if __name__=="__main__":
 usage = """
%prog [-d|--dump] infile.dfu
%prog {-b|--build} file.bin [{-D|--device}=vendor:device] outfile.dfu"""
 parser = OptionParser(usage=usage)
 parser.add_option("-b", "--build", action="store", dest="binfile",
 help="build a DFU file from given BINFILE", metavar="BINFILE")
 parser.add_option("-D", "--device", action="store", dest="device",
 help="build for DEVICE, defaults to %s" % DEFAULT_DEVICE, metavar="DEVICE")
 parser.add_option("-d", "--dump", action="store_true", dest="dump_images",
 default=False, help="dump contained images to current directory")
 (options, args) = parser.parse_args()

 if options.binfile and len(args)==1:
 binfile = options.binfile
 if not os.path.isfile(binfile):
 print ("Unreadable file '%s'." % binfile)
 sys.exit(1)
 target = open(binfile,'rb').read()
 outfile = args[0]
 device = DEFAULT_DEVICE
 # If a device is specified, parse the pair into a VID:PID pair
 # in order to validate them.
 if options.device:
 device=options.device
 try:
 v,d=map(lambda x: int(x,0) & 0xFFFF, device.split(':',1))
 except:
 print ("Invalid device '%s'." % device)
 sys.exit(1)
 build(outfile,target,device)
 elif len(args)==1:
 infile = args[0]
 if not os.path.isfile(infile):
 print ("Unreadable file '%s'." % infile)
 sys.exit(1)
 parse(infile, dump_images=options.dump_images)
 else:
 parser.print_help()
 sys.exit(1)