Class Struct

test/tests/usb_msd.py:236–279

Base class for a C structure

class Struct(object):
    """Base class for a C structure"""

    def __init__(self, name, structure, data):
        field_list = [field[0] for field in structure]
        fmt_list = [field[1] for field in structure]
        format_str = "<" + "".join(fmt_list)
        struct_size = struct.calcsize(format_str)
        value_list = struct.unpack(format_str, data[:struct_size])
        value_dict = {}
        for name, value in zip(field_list, value_list):
            value_dict[name] = value
        self.name = name
        self.format_str = format_str
        self.field_list = field_list
        self.fmt_dict = {k: fmt_list[i] for i, k in enumerate(field_list)}
        self.value_dict = value_dict
        self.size = struct_size

    def __getitem__(self, key):
        return self.value_dict[key]

    def __setitem__(self, key, value):
        self.value_dict[key] = value

    def __str__(self):
        desc = ""
        desc += self.name + ":" + os.linesep
        for field in self.field_list:
            value = self.value_dict[field]
            if isinstance(value, bytes):
                value = list(bytearray(value))
            desc += ("    %s=%s" + os.linesep) % (field, value)
        return desc

    def pack(self):
        """Return a byte representation of this structure"""
        value_list = []
        for field in self.field_list:
            value = self.value_dict[field]
            if self.fmt_dict[field].endswith('s'):
                value = six.ensure_binary(value)
            value_list.append(value)
        return struct.pack(self.format_str, *value_list)


class MBR(Struct):