#!/usr/bin/python3

# Written by Antonio Galea - 2010/11/18
# Distributed under Gnu LGPL 3.0
# see http://www.gnu.org/licenses/lgpl-3.0.txt

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

try:
  from intelhex import IntelHex
except ImportError:
  IntelHex = None

DEFAULT_DEVICE="0x0483:0xdf11"
DEFAULT_NAME=b'ST...'

# Prefix and Suffix sizes are derived from ST's DfuSe File Format Specification (UM0391), DFU revision 1.1a
PREFIX_SIZE=11
SUFFIX_SIZE=16

def named(tuple,names):
  return dict(list(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(bytestring):
  return bytestring.partition(b'\0')[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])
  prefix, data = consume('<5sBIB',data,'signature version size targets')
  print('%(signature)s v%(version)d, image size: %(size)d, targets: %(targets)d' % prefix)
  for t in range(prefix['targets']):
    tprefix, data  = consume('<6sBI255s2I',data,'signature altsetting named name size elements')
    tprefix['num'] = t
    if tprefix['named']:
      tprefix['name'] = cstring(tprefix['name'])
    else:
      tprefix['name'] = ''
    print('%(signature)s %(num)d, alt setting: %(altsetting)s, name: "%(name)s", size: %(size)d, elements: %(elements)d' % tprefix)
    tsize = tprefix['size']
    target, data = data[:tsize], data[tsize:]
    for e in range(tprefix['elements']):
      eprefix, target = consume('<2I',target,'address size')
      eprefix['num'] = e
      print('  %(num)d, address: 0x%(address)08x, size: %(size)d' % eprefix)
      esize = eprefix['size']
      image, target = target[:esize], target[esize:]
      if dump_images:
        out = '%s.target%d.image%d.bin' % (file,t,e)
        open(out,'wb').write(image)
        print('    DUMPED IMAGE TO "%s"' % out)
    if len(target):
      print("target %d: PARSE ERROR" % t)
  suffix = named(struct.unpack('<4H3sBI',data[:SUFFIX_SIZE]),'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[SUFFIX_SIZE:]
  if data:
    print("PARSE ERROR")

def checkbin(binfile):
  data = open(binfile,'rb').read()
  if (len(data) < SUFFIX_SIZE):
    return
  crc = compute_crc(data[:-4])
  suffix = named(struct.unpack('<4H3sBI',data[-SUFFIX_SIZE:]),'device product vendor dfu ufd len crc')
  if crc == suffix['crc'] and suffix['ufd'] == b'UFD':
    print('usb: %(vendor)04x:%(product)04x, device: 0x%(device)04x, dfu: 0x%(dfu)04x, %(ufd)s, %(len)d, 0x%(crc)08x' % suffix)
    print("It looks like the file %s has a DFU suffix!" % binfile)
    print("Please remove any DFU suffix and retry.")
    sys.exit(1)

def build(file,targets,name=DEFAULT_NAME,device=DEFAULT_DEVICE):
  data = b''
  for t,target in enumerate(targets):
    tdata = b''
    for image in target:
      tdata += struct.pack('<2I',image['address'],len(image['data']))+image['data']
      ealt = image['alt']
    tdata = struct.pack('<6sBI255s2I',b'Target',ealt,1,name,len(tdata),len(target)) + tdata
    data += tdata
  data  = struct.pack('<5sBIB',b'DfuSe',1,PREFIX_SIZE + len(data) + SUFFIX_SIZE,len(targets)) + data
  v,d=[int(x,0) & 0xFFFF for x in device.split(':',1)]
  data += struct.pack('<4H3sB',0,d,v,0x011a,b'UFD',SUFFIX_SIZE)
  crc   = compute_crc(data)
  data += struct.pack('<I',crc)
  open(file,'wb').write(data)

if __name__=="__main__":
  usage = """
%prog [-d|--dump] infile.dfu
%prog {-b|--build} address:file.bin [-b address:file.bin ...] [{-D|--device}=vendor:device] outfile.dfu
%prog {-s|--build-s19} file.s19 [{-D|--device}=vendor:device] outfile.dfu
%prog {-i|--build-ihex} file.hex [-i file.hex ...] [{-D|--device}=vendor:device] outfile.dfu"""
  parser = OptionParser(usage=usage)
  parser.add_option("-b", "--build", action="append", dest="binfiles",
    help="Include a raw binary file, to be loaded at the specified address. The BINFILES argument is of the form address:path-to-file. The address can have @X appended where X is the alternate interface number for this binary file. Note that the binary files must not have any DFU suffix!", metavar="BINFILES")
  parser.add_option("-i", "--build-ihex", action="append", dest="hexfiles",
    help="build a DFU file from given Intel HEX HEXFILES", metavar="HEXFILES")
  parser.add_option("-s", "--build-s19", type="string", dest="s19files",
    help="build a DFU file from given S19 S-record S19FILE", metavar="S19FILE")
  parser.add_option("-D", "--device", action="store", dest="device",
    help="build for DEVICE, defaults to %s" % DEFAULT_DEVICE, metavar="DEVICE")
  parser.add_option("-a", "--alt-intf", action="store", dest="alt",
    help="build for alternate interface number ALTINTF, defaults to 0", metavar="ALTINTF")
  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()

  targets = []

  if options.alt:
    try:
      default_alt = int(options.alt)
    except ValueError:
      print("Alternate interface option argument %s invalid." % options.alt)
      sys.exit(1)
  else:
    default_alt = 0

  if (options.binfiles or options.hexfiles) and len(args)==1:
    target = []
    old_ealt = None

    if options.binfiles:
      for arg in options.binfiles:
        try:
          address,binfile = arg.split(':',1)
        except ValueError:
          print("Address:file couple '%s' invalid." % arg)
          sys.exit(1)
        try:
          address,alts = address.split('@',1)
          if alts:
            try:
              ealt = int(alts)
            except ValueError:
              print("Alternate interface number %s invalid." % alts)
              sys.exit(1)
          else:
            ealt = default_alt
        except ValueError:
            ealt = default_alt
        try:
          address = int(address,0) & 0xFFFFFFFF
        except ValueError:
          print("Address %s invalid." % address)
          sys.exit(1)
        if not os.path.isfile(binfile):
          print("Unreadable file '%s'." % binfile)
          sys.exit(1)
        checkbin(binfile)
        if old_ealt is not None and ealt != old_ealt:
          targets.append(target)
          target = []
        target.append({ 'address': address, 'alt': ealt, 'data': open(binfile,'rb').read() })
        old_ealt = ealt
      targets.append(target)

    if options.hexfiles:
      if not IntelHex:
        print("Error: IntelHex python module could not be found")
        sys.exit(1)
      for hexf in options.hexfiles:
        ih = IntelHex(hexf)
        for (address,end) in ih.segments():
          try:
            address = address & 0xFFFFFFFF
          except ValueError:
            print("Address %s invalid." % address)
            sys.exit(1)
          target.append({ 'address': address, 'alt': default_alt, 'data': ih.tobinstr(start=address, end=end-1)})
      targets.append(target)

    outfile = args[0]
    device = DEFAULT_DEVICE
    if options.device:
      device=options.device
    try:
      v,d=[int(x,0) & 0xFFFF for x in device.split(':',1)]
    except:
      print("Invalid device '%s'." % device)
      sys.exit(1)
    build(outfile,targets,DEFAULT_NAME,device)
  elif options.s19files and len(args)==1:
    address = 0
    data = ""
    target = []
    name = DEFAULT_NAME
    with open(options.s19files) as f:
      lines = f.readlines()
      for line in lines:
          curaddress = 0
          curdata = ""
          line = line.rstrip()
          if line.startswith ( "S0" ):
            name = binascii.a2b_hex(line[8:len(line) - 2])
          elif line.startswith ( "S3" ):
            try:
              curaddress = int(line[4:12], 16) & 0xFFFFFFFF
            except ValueError:
              print("Address %s invalid." % address)
              sys.exit(1)
            curdata = binascii.unhexlify(line[12:-2])
          elif line.startswith ( "S2" ):
            try:
              curaddress = int(line[4:10], 16) & 0xFFFFFFFF
            except ValueError:
              print("Address %s invalid." % address)
              sys.exit(1)
            curdata = binascii.unhexlify(line[10:-2])
          elif line.startswith ( "S1" ):
            try:
              curaddress = int(line[4:8], 16) & 0xFFFFFFFF
            except ValueError:
              print("Address %s invalid." % address)
              sys.exit(1)
            curdata = binascii.unhexlify(line[8:-2])
          if address == 0:
              address = curaddress
              data = curdata
          elif address + len(data) != curaddress:
              target.append({ 'address': address, 'alt': default_alt, 'data': data })
              address = curaddress
              data = curdata
          else:
              data += curdata
    outfile = args[0]
    device = DEFAULT_DEVICE
    if options.device:
      device=options.device
    try:
      v,d=[int(x,0) & 0xFFFF for x in device.split(':',1)]
    except:
      print("Invalid device '%s'." % device)
      sys.exit(1)
    build(outfile,[target],name,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()
    if not IntelHex:
      print("Note: Intel hex files support requires the IntelHex python module")
    sys.exit(1)