mirror of https://github.com/python/cpython
230 lines
7.3 KiB
Python
230 lines
7.3 KiB
Python
#
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# Secret Labs' Regular Expression Engine
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#
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# convert template to internal format
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#
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# Copyright (c) 1997-2000 by Secret Labs AB. All rights reserved.
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#
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# Portions of this engine have been developed in cooperation with
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# CNRI. Hewlett-Packard provided funding for 1.6 integration and
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# other compatibility work.
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#
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import array
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import _sre
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from sre_constants import *
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# find an array type code that matches the engine's code size
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for WORDSIZE in "BHil":
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if len(array.array(WORDSIZE, [0]).tostring()) == _sre.getcodesize():
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break
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else:
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raise RuntimeError, "cannot find a useable array type"
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def _compile(code, pattern, flags):
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# internal: compile a (sub)pattern
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emit = code.append
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for op, av in pattern:
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if op in (LITERAL, NOT_LITERAL):
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if flags & SRE_FLAG_IGNORECASE:
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emit(OPCODES[OP_IGNORE[op]])
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else:
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emit(OPCODES[op])
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emit(av)
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elif op is IN:
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if flags & SRE_FLAG_IGNORECASE:
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emit(OPCODES[OP_IGNORE[op]])
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def fixup(literal, flags=flags):
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return _sre.getlower(literal, flags)
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else:
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emit(OPCODES[op])
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fixup = lambda x: x
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skip = len(code); emit(0)
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for op, av in av:
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emit(OPCODES[op])
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if op is NEGATE:
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pass
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elif op is LITERAL:
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emit(fixup(av))
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elif op is RANGE:
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emit(fixup(av[0]))
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emit(fixup(av[1]))
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elif op is CATEGORY:
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if flags & SRE_FLAG_LOCALE:
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emit(CHCODES[CH_LOCALE[av]])
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elif flags & SRE_FLAG_UNICODE:
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emit(CHCODES[CH_UNICODE[av]])
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else:
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emit(CHCODES[av])
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else:
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raise error, "internal: unsupported set operator"
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emit(OPCODES[FAILURE])
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code[skip] = len(code) - skip
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elif op is ANY:
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if flags & SRE_FLAG_DOTALL:
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emit(OPCODES[op])
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else:
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emit(OPCODES[CATEGORY])
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emit(CHCODES[CATEGORY_NOT_LINEBREAK])
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elif op in (REPEAT, MIN_REPEAT, MAX_REPEAT):
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if flags & SRE_FLAG_TEMPLATE:
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emit(OPCODES[REPEAT])
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skip = len(code); emit(0)
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emit(av[0])
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emit(av[1])
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_compile(code, av[2], flags)
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emit(OPCODES[SUCCESS])
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code[skip] = len(code) - skip
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else:
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lo, hi = av[2].getwidth()
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if lo == 0:
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raise error, "nothing to repeat"
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if 0 and lo == hi == 1 and op is MAX_REPEAT:
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# FIXME: <fl> need a better way to figure out when
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# it's safe to use this one (in the parser, probably)
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emit(OPCODES[MAX_REPEAT_ONE])
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skip = len(code); emit(0)
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emit(av[0])
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emit(av[1])
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_compile(code, av[2], flags)
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emit(OPCODES[SUCCESS])
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code[skip] = len(code) - skip
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else:
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emit(OPCODES[op])
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skip = len(code); emit(0)
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emit(av[0])
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emit(av[1])
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_compile(code, av[2], flags)
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emit(OPCODES[SUCCESS])
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code[skip] = len(code) - skip
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elif op is SUBPATTERN:
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group = av[0]
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if group:
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emit(OPCODES[MARK])
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emit((group-1)*2)
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_compile(code, av[1], flags)
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if group:
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emit(OPCODES[MARK])
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emit((group-1)*2+1)
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elif op in (SUCCESS, FAILURE):
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emit(OPCODES[op])
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elif op in (ASSERT, ASSERT_NOT, CALL):
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emit(OPCODES[op])
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skip = len(code); emit(0)
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_compile(code, av, flags)
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emit(OPCODES[SUCCESS])
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code[skip] = len(code) - skip
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elif op is AT:
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emit(OPCODES[op])
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if flags & SRE_FLAG_MULTILINE:
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emit(ATCODES[AT_MULTILINE[av]])
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else:
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emit(ATCODES[av])
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elif op is BRANCH:
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emit(OPCODES[op])
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tail = []
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for av in av[1]:
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skip = len(code); emit(0)
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_compile(code, av, flags)
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emit(OPCODES[JUMP])
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tail.append(len(code)); emit(0)
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code[skip] = len(code) - skip
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emit(0) # end of branch
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for tail in tail:
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code[tail] = len(code) - tail
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elif op is CATEGORY:
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emit(OPCODES[op])
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if flags & SRE_FLAG_LOCALE:
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emit(CHCODES[CH_LOCALE[av]])
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elif flags & SRE_FLAG_UNICODE:
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emit(CHCODES[CH_UNICODE[av]])
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else:
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emit(CHCODES[av])
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elif op is GROUP:
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if flags & SRE_FLAG_IGNORECASE:
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emit(OPCODES[OP_IGNORE[op]])
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else:
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emit(OPCODES[op])
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emit(av-1)
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elif op is MARK:
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emit(OPCODES[op])
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emit(av)
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else:
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raise ValueError, ("unsupported operand type", op)
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def _compile_info(code, pattern, flags):
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# internal: compile an info block. in the current version,
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# this contains min/max pattern width and a literal prefix,
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# if any
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lo, hi = pattern.getwidth()
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if lo == 0:
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return # not worth it
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# look for a literal prefix
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prefix = []
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if not (flags & SRE_FLAG_IGNORECASE):
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for op, av in pattern.data:
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if op is LITERAL:
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prefix.append(av)
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else:
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break
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# add an info block
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emit = code.append
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emit(OPCODES[INFO])
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skip = len(code); emit(0)
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# literal flag
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mask = 0
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if len(prefix) == len(pattern.data):
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mask = 1
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emit(mask)
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# pattern length
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emit(lo)
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if hi < 32768:
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emit(hi)
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else:
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emit(0)
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# add literal prefix
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emit(len(prefix))
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if prefix:
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code.extend(prefix)
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# generate overlap table
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table = [-1] + ([0]*len(prefix))
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for i in range(len(prefix)):
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table[i+1] = table[i]+1
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while table[i+1] > 0 and prefix[i] != prefix[table[i+1]-1]:
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table[i+1] = table[table[i+1]-1]+1
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code.extend(table[1:]) # don't store first entry
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code[skip] = len(code) - skip
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def compile(p, flags=0):
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# internal: convert pattern list to internal format
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# compile, as necessary
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if type(p) in (type(""), type(u"")):
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import sre_parse
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pattern = p
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p = sre_parse.parse(p)
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else:
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pattern = None
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flags = p.pattern.flags | flags
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code = []
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# compile info block
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_compile_info(code, p, flags)
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# compile the pattern
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_compile(code, p.data, flags)
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code.append(OPCODES[SUCCESS])
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# FIXME: <fl> get rid of this limitation!
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assert p.pattern.groups <= 100,\
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"sorry, but this version only supports 100 named groups"
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return _sre.compile(
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pattern, flags,
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array.array(WORDSIZE, code).tostring(),
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p.pattern.groups-1, p.pattern.groupdict
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)
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