def convert_from_uf2()

in utils/uf2conv.py [0:0]

• 72 lines of code
• 32 McCabe index (conditional complexity)

def convert_from_uf2(buf):
    global appstartaddr
    global familyid
    numblocks = len(buf) // 512
    curraddr = None
    currfamilyid = None
    families_found = {}
    prev_flag = None
    all_flags_same = True
    outp = []
    for blockno in range(numblocks):
        ptr = blockno * 512
        block = buf[ptr:ptr + 512]
        hd = struct.unpack(b"<IIIIIIII", block[0:32])
        if hd[0] != UF2_MAGIC_START0 or hd[1] != UF2_MAGIC_START1:
            print("Skipping block at " + ptr + "; bad magic")
            continue
        if hd[2] & 1:
            # NO-flash flag set; skip block
            continue
        datalen = hd[4]
        if datalen > 476:
            assert False, "Invalid UF2 data size at " + ptr
        newaddr = hd[3]
        if (hd[2] & 0x2000) and (currfamilyid == None):
            currfamilyid = hd[7]
        if curraddr == None or ((hd[2] & 0x2000) and hd[7] != currfamilyid):
            currfamilyid = hd[7]
            curraddr = newaddr
            if familyid == 0x0 or familyid == hd[7]:
                appstartaddr = newaddr
        padding = newaddr - curraddr
        if padding < 0:
            assert False, "Block out of order at " + ptr
        if padding > 10*1024*1024:
            assert False, "More than 10M of padding needed at " + ptr
        if padding % 4 != 0:
            assert False, "Non-word padding size at " + ptr
        while padding > 0:
            padding -= 4
            outp += b"\x00\x00\x00\x00"
        if familyid == 0x0 or ((hd[2] & 0x2000) and familyid == hd[7]):
            outp.append(block[32 : 32 + datalen])
        curraddr = newaddr + datalen
        if hd[2] & 0x2000:
            if hd[7] in families_found.keys():
                if families_found[hd[7]] > newaddr:
                    families_found[hd[7]] = newaddr
            else:
                families_found[hd[7]] = newaddr
        if prev_flag == None:
            prev_flag = hd[2]
        if prev_flag != hd[2]:
            all_flags_same = False
        if blockno == (numblocks - 1):
            print("--- UF2 File Header Info ---")
            families = load_families()
            for family_hex in families_found.keys():
                family_short_name = ""
                for name, value in families.items():
                    if value == family_hex:
                        family_short_name = name
                print("Family ID is {:s}, hex value is 0x{:08x}".format(family_short_name,family_hex))
                print("Target Address is 0x{:08x}".format(families_found[family_hex]))
            if all_flags_same:
                print("All block flag values consistent, 0x{:04x}".format(hd[2]))
            else:
                print("Flags were not all the same")
            print("----------------------------")
            if len(families_found) > 1 and familyid == 0x0:
                outp = []
                appstartaddr = 0x0
    return b"".join(outp)