100 lines
2.5 KiB
Python
100 lines
2.5 KiB
Python
from __future__ import absolute_import, print_function, division
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import os.path
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import re
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import importlib
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import inspect
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def setbit(byte, offset, value):
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"""
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Set a bit in a byte to 1 if value is truthy, 0 if not.
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"""
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if value:
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return byte | (1 << offset)
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else:
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return byte & ~(1 << offset)
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def getbit(byte, offset):
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mask = 1 << offset
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return bool(byte & mask)
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class BiDi(object):
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"""
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A wee utility class for keeping bi-directional mappings, like field
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constants in protocols. Names are attributes on the object, dict-like
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access maps values to names:
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CONST = BiDi(a=1, b=2)
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assert CONST.a == 1
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assert CONST.get_name(1) == "a"
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"""
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def __init__(self, **kwargs):
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self.names = kwargs
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self.values = {}
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for k, v in kwargs.items():
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self.values[v] = k
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if len(self.names) != len(self.values):
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raise ValueError("Duplicate values not allowed.")
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def __getattr__(self, k):
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if k in self.names:
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return self.names[k]
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raise AttributeError("No such attribute: %s", k)
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def get_name(self, n, default=None):
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return self.values.get(n, default)
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class Data(object):
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def __init__(self, name):
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m = importlib.import_module(name)
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dirname = os.path.dirname(inspect.getsourcefile(m))
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self.dirname = os.path.abspath(dirname)
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def push(self, subpath):
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"""
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Change the data object to a path relative to the module.
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"""
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self.dirname = os.path.join(self.dirname, subpath)
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return self
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def path(self, path):
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"""
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Returns a path to the package data housed at 'path' under this
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module.Path can be a path to a file, or to a directory.
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This function will raise ValueError if the path does not exist.
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"""
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fullpath = os.path.join(self.dirname, path)
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if not os.path.exists(fullpath):
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raise ValueError("dataPath: %s does not exist." % fullpath)
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return fullpath
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_label_valid = re.compile(b"(?!-)[A-Z\d-]{1,63}(?<!-)$", re.IGNORECASE)
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def is_valid_host(host):
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# type: (bytes) -> bool
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"""
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Checks if a hostname is valid.
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"""
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try:
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host.decode("idna")
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except ValueError:
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return False
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if len(host) > 255:
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return False
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if host and host[-1:] == b".":
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host = host[:-1]
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return all(_label_valid.match(x) for x in host.split(b"."))
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def is_valid_port(port):
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return 0 <= port <= 65535
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