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import re |
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2
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3
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4
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class BitField(object): |
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5
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def __init__(self, enum): |
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6
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if not all(isinstance(member.value, int) for member in enum): |
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msg = 'Enum {} members must have integer values'.format(repr(enum)) |
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raise TypeError(msg) |
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9
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try: |
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10
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assert enum(0) |
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11
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msg = 'Cannot construct BitField from {} with a value for 0: {}' |
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raise TypeError(msg.format(repr(enum), enum(0))) |
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except ValueError: |
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# A ValueError is raised if the enum does not have a value for 0 |
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pass |
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self.enum = enum |
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def __repr__(self): |
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return 'BitField({})'.format(self.enum) |
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def __str__(self): |
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return 'BitField({})'.format(self.enum) |
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def pack(self, arg): |
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""" |
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Take a list (or single value) and bitwise-or all the values together |
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""" |
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if arg: |
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# Handle a variety of inputs: list or single, enum or raw |
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if isinstance(arg, list): |
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arg_list = arg |
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else: |
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arg_list = [arg] |
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# To make usage a bit nice/easier if the elements of the list |
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# are strings assume that they are enum names and attempt to |
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# convert them to the correct enumeration values. |
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value = 0 |
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for item in arg_list: |
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if isinstance(item, self.enum): |
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value |= item.value |
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elif isinstance(item, str): |
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try: |
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value |= getattr(self.enum, item).value |
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except AttributeError: |
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enum_name = re.match(r"<enum '(\S+)'>", str(self.enum)).group(1) |
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msg = '{} is not a valid {}'.format(item, enum_name) |
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raise ValueError(msg) |
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else: |
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# Assume that the item is an integer value, convert it to |
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# an enum value to ensure it is a valid value for this |
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# bitfield. |
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value |= self.enum(item).value |
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return value |
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else: |
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return 0 |
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59
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def unpack(self, val): |
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60
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""" |
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61
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Take a single number and split it out into all values that are present |
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62
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""" |
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63
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return frozenset(e for e in self.enum if e.value & val) |
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64
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65
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def make(self, arg): |
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66
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""" |
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67
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Take an input list and return a frozenset |
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68
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69
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useful for testing |
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70
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""" |
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# Handle the same inputs as the pack function |
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if isinstance(arg, list): |
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values = [self.enum(value) for value in arg] |
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else: |
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values = [self.enum(arg)] |
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77
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# return this list as a frozenset |
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return frozenset(values) |
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sprout42 /
StarStruct
