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Diffstat (limited to 'python/vyos/range_regex.py')
| -rw-r--r-- | python/vyos/range_regex.py | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/python/vyos/range_regex.py b/python/vyos/range_regex.py new file mode 100644 index 000000000..a8190d140 --- /dev/null +++ b/python/vyos/range_regex.py @@ -0,0 +1,142 @@ +'''Copyright (c) 2013, Dmitry Voronin +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + +1. Redistributions of source code must retain the above copyright notice, this +list of conditions and the following disclaimer. + +2. Redistributions in binary form must reproduce the above copyright notice, +this list of conditions and the following disclaimer in the documentation +and/or other materials provided with the distribution. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +''' +import math + +# coding=utf8 + +# Split range to ranges that has its unique pattern. +# Example for 12-345: +# +# 12- 19: 1[2-9] +# 20- 99: [2-9]\d +# 100-299: [1-2]\d{2} +# 300-339: 3[0-3]\d +# 340-345: 34[0-5] + +def range_to_regex(inpt_range): + if isinstance(inpt_range, str): + range_list = inpt_range.split('-') + # Check input arguments + if len(range_list) == 2: + # The first element in range must be higher then the second + if int(range_list[0]) < int(range_list[1]): + return regex_for_range(int(range_list[0]), int(range_list[1])) + + return None + +def bounded_regex_for_range(min_, max_): + return r'\b({})\b'.format(regex_for_range(min_, max_)) + +def regex_for_range(min_, max_): + """ + > regex_for_range(12, 345) + '1[2-9]|[2-9]\d|[1-2]\d{2}|3[0-3]\d|34[0-5]' + """ + positive_subpatterns = [] + negative_subpatterns = [] + + if min_ < 0: + min__ = 1 + if max_ < 0: + min__ = abs(max_) + max__ = abs(min_) + + negative_subpatterns = split_to_patterns(min__, max__) + min_ = 0 + + if max_ >= 0: + positive_subpatterns = split_to_patterns(min_, max_) + + negative_only_subpatterns = ['-' + val for val in negative_subpatterns if val not in positive_subpatterns] + positive_only_subpatterns = [val for val in positive_subpatterns if val not in negative_subpatterns] + intersected_subpatterns = ['-?' + val for val in negative_subpatterns if val in positive_subpatterns] + + subpatterns = negative_only_subpatterns + intersected_subpatterns + positive_only_subpatterns + return '|'.join(subpatterns) + + +def split_to_patterns(min_, max_): + subpatterns = [] + + start = min_ + for stop in split_to_ranges(min_, max_): + subpatterns.append(range_to_pattern(start, stop)) + start = stop + 1 + + return subpatterns + + +def split_to_ranges(min_, max_): + stops = {max_} + + nines_count = 1 + stop = fill_by_nines(min_, nines_count) + while min_ <= stop < max_: + stops.add(stop) + + nines_count += 1 + stop = fill_by_nines(min_, nines_count) + + zeros_count = 1 + stop = fill_by_zeros(max_ + 1, zeros_count) - 1 + while min_ < stop <= max_: + stops.add(stop) + + zeros_count += 1 + stop = fill_by_zeros(max_ + 1, zeros_count) - 1 + + stops = list(stops) + stops.sort() + + return stops + + +def fill_by_nines(integer, nines_count): + return int(str(integer)[:-nines_count] + '9' * nines_count) + + +def fill_by_zeros(integer, zeros_count): + return integer - integer % 10 ** zeros_count + + +def range_to_pattern(start, stop): + pattern = '' + any_digit_count = 0 + + for start_digit, stop_digit in zip(str(start), str(stop)): + if start_digit == stop_digit: + pattern += start_digit + elif start_digit != '0' or stop_digit != '9': + pattern += '[{}-{}]'.format(start_digit, stop_digit) + else: + any_digit_count += 1 + + if any_digit_count: + pattern += r'\d' + + if any_digit_count > 1: + pattern += '{{{}}}'.format(any_digit_count) + + return pattern
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