91 lines
3.3 KiB
Python
91 lines
3.3 KiB
Python
# Copyright 2012 Matt Chaput. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are met:
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#
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# 1. Redistributions of source code must retain the above copyright notice,
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# this list of conditions and the following disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY MATT CHAPUT ``AS IS'' AND ANY EXPRESS OR
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# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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# EVENT SHALL MATT CHAPUT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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# OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and documentation are
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# those of the authors and should not be interpreted as representing official
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# policies, either expressed or implied, of Matt Chaput.
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from whoosh.automata.fsa import ANY, EPSILON, NFA
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# Constants for glob
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_LIT = 0
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_STAR = 1
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_PLUS = 2
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_QUEST = 3
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_RANGE = 4
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def parse_glob(pattern, _glob_multi="*", _glob_single="?",
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_glob_range1="[", _glob_range2="]"):
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pos = 0
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last = None
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while pos < len(pattern):
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char = pattern[pos]
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pos += 1
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if char == _glob_multi: # *
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# (Ignore more than one star in a row)
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if last is not _STAR:
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yield _STAR, None
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last = _STAR
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elif char == _glob_single: # ?
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# (Ignore ? after a star)
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if last is not _STAR:
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yield _QUEST, None
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last = _QUEST
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elif char == _glob_range1: # [
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chars = set()
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negate = False
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# Take the char range specification until the ]
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while pos < len(pattern):
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char = pattern[pos]
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pos += 1
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if char == _glob_range2:
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break
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chars.add(char)
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if chars:
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yield _RANGE, (chars, negate)
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last = _RANGE
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else:
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yield _LIT, char
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last = _LIT
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def glob_automaton(pattern):
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nfa = NFA(0)
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i = -1
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for i, (op, arg) in enumerate(parse_glob(pattern)):
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if op is _LIT:
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nfa.add_transition(i, arg, i + 1)
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elif op is _STAR:
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nfa.add_transition(i, ANY, i + 1)
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nfa.add_transition(i, EPSILON, i + 1)
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nfa.add_transition(i + 1, EPSILON, i)
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elif op is _QUEST:
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nfa.add_transition(i, ANY, i + 1)
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elif op is _RANGE:
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for char in arg[0]:
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nfa.add_transition(i, char, i + 1)
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nfa.add_final_state(i + 1)
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return nfa
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