51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
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"""
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Binary Data Interfaces
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Abstract:
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Helper classes for working with binary data structures. This simplifies data
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field extraction from a binary buffer.
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Author: Patrick C. McGinty (pyweather@tuxcoder.com)
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Date: 2010-06-025
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"""
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import struct
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class Struct(struct.Struct):
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"""
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Implements a reusable class for working with a binary data structure. It
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provides a named fields interface, similar to C structures.
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Usage: 1) subclass and extend _post_unpack method
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2) instantiate directly, if no 'post unpack' processing needed
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Arguments:
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See `struct.Struct` class definition.
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"""
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def __init__(self, fmt, order='@'):
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self.fields, fmt_t = list(zip(*fmt))
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super(Struct, self).__init__(order + ''.join(fmt_t))
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def unpack(self, buf):
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"""
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see unpack_from()
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"""
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return self.unpack_from(buf, offset=0)
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def unpack_from(self, buf, offset=0):
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"""
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unpacks data from 'buf' and returns a dictation of named fields. the
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fields can be post-processed by extending the _post_unpack() method.
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"""
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data = super(Struct, self).unpack_from(buf, offset)
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items = dict(list(zip(self.fields, data)))
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return self._post_unpack(items)
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def _post_unpack(self, items):
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"""
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perform data modification of any values, after unpacking from a buffer.
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"""
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return items
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