65 lines
2.0 KiB
Python
65 lines
2.0 KiB
Python
# Copyright 2017 by Rackspace Hosting, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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class IntConverter(object):
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"""Converts a field value to an int.
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Keyword Args:
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num_digits (int): Require the value to have the given
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number of digits.
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min (int): Reject the value if it is less than this value.
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max (int): Reject the value if it is greater than this value.
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"""
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__slots__ = ('_num_digits', '_min', '_max')
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def __init__(self, num_digits=None, min=None, max=None):
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if num_digits is not None and num_digits < 1:
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raise ValueError('num_digits must be at least 1')
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self._num_digits = num_digits
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self._min = min
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self._max = max
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def convert(self, fragment):
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if self._num_digits is not None and len(fragment) != self._num_digits:
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return None
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# NOTE(kgriffs): int() will accept numbers with preceding or
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# trailing whitespace, so we need to do our own check. Using
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# strip() is faster than either a regex or a series of or'd
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# membership checks via "in", esp. as the length of contiguous
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# numbers in the fragment grows.
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if fragment.strip() != fragment:
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return None
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try:
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value = int(fragment)
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except ValueError:
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return None
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if self._min is not None and value < self._min:
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return None
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if self._max is not None and value > self._max:
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return None
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return value
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BUILTIN = (
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('int', IntConverter),
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)
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