struct issue

[oli]

Hi,

i have a strange issue:

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>>> struct.unpack('>B', '\x7f')[0]
127
>>> struct.unpack('>B', '\x80')[0]
194

As fa as the documentation from python / struct says, "B" is an unsigned int, and so it should give the correct value of 128 - or am i wrong?

thanks!
Oli

[pythoncoder]

The buffer argument should be a bytes object thus:

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>>> import ustruct as struct
>>> struct.unpack('>B', b'\x80')[0]
128
>>> 

[deshipu]

The value `"\x80"` is somewhat unfortunate, as it has special meaning in utf8, which is used by default in non-byte strings.

[pythoncoder]

Passing a string as the second arg is invalid. Alas MicroPython fails silently; Cpython provides an explanatory error message:

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>>> import struct
>>> struct.unpack('>B', '\x7f')[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' does not support the buffer interface
>>> 

With a bytes or bytearray instance, all possible 8-bit values are acceptable.