| # |
| # Secret Labs' Regular Expression Engine |
| # |
| # convert template to internal format |
| # |
| # Copyright (c) 1997-2000 by Secret Labs AB. All rights reserved. |
| # |
| # Portions of this engine have been developed in cooperation with |
| # CNRI. Hewlett-Packard provided funding for 2.0 integration and |
| # other compatibility work. |
| # |
| |
| import _sre |
| |
| from sre_constants import * |
| |
| MAXCODE = 65535 |
| |
| def _charset(charset, fixup=None): |
| # internal: optimize character set |
| if not fixup: |
| fixup = lambda x: x |
| out = [] |
| charmap = [0]*256 |
| try: |
| for op, av in charset: |
| if op is NEGATE: |
| out.append((op, av)) |
| elif op is LITERAL: |
| charmap[fixup(av)] = 1 |
| elif op is RANGE: |
| for i in range(fixup(av[0]), fixup(av[1])+1): |
| charmap[i] = 1 |
| elif op is CATEGORY: |
| # FIXME: could append to charmap tail |
| return charset # cannot compress |
| except IndexError: |
| # unicode |
| return charset |
| # compress character map |
| i = p = n = 0 |
| runs = [] |
| for c in charmap: |
| if c: |
| if n == 0: |
| p = i |
| n = n + 1 |
| elif n: |
| runs.append((p, n)) |
| n = 0 |
| i = i + 1 |
| if n: |
| runs.append((p, n)) |
| if len(runs) <= 2: |
| # use literal/range |
| for p, n in runs: |
| if n == 1: |
| out.append((LITERAL, p)) |
| else: |
| out.append((RANGE, (p, p+n-1))) |
| if len(out) < len(charset): |
| return out |
| else: |
| # use bitmap |
| data = [] |
| m = 1; v = 0 |
| for c in charmap: |
| if c: |
| v = v + m |
| m = m << 1 |
| if m > MAXCODE: |
| data.append(v) |
| m = 1; v = 0 |
| out.append((CHARSET, data)) |
| return out |
| return charset |
| |
| def _compile(code, pattern, flags): |
| # internal: compile a (sub)pattern |
| emit = code.append |
| for op, av in pattern: |
| if op in (LITERAL, NOT_LITERAL): |
| if flags & SRE_FLAG_IGNORECASE: |
| emit(OPCODES[OP_IGNORE[op]]) |
| else: |
| emit(OPCODES[op]) |
| emit(av) |
| elif op is IN: |
| if flags & SRE_FLAG_IGNORECASE: |
| emit(OPCODES[OP_IGNORE[op]]) |
| def fixup(literal, flags=flags): |
| return _sre.getlower(literal, flags) |
| else: |
| emit(OPCODES[op]) |
| fixup = lambda x: x |
| skip = len(code); emit(0) |
| for op, av in _charset(av, fixup): |
| emit(OPCODES[op]) |
| if op is NEGATE: |
| pass |
| elif op is LITERAL: |
| emit(fixup(av)) |
| elif op is RANGE: |
| emit(fixup(av[0])) |
| emit(fixup(av[1])) |
| elif op is CHARSET: |
| code.extend(av) |
| elif op is CATEGORY: |
| if flags & SRE_FLAG_LOCALE: |
| emit(CHCODES[CH_LOCALE[av]]) |
| elif flags & SRE_FLAG_UNICODE: |
| emit(CHCODES[CH_UNICODE[av]]) |
| else: |
| emit(CHCODES[av]) |
| else: |
| raise error, "internal: unsupported set operator" |
| emit(OPCODES[FAILURE]) |
| code[skip] = len(code) - skip |
| elif op is ANY: |
| if flags & SRE_FLAG_DOTALL: |
| emit(OPCODES[op]) |
| else: |
| emit(OPCODES[CATEGORY]) |
| emit(CHCODES[CATEGORY_NOT_LINEBREAK]) |
| elif op in (REPEAT, MIN_REPEAT, MAX_REPEAT): |
| if flags & SRE_FLAG_TEMPLATE: |
| emit(OPCODES[REPEAT]) |
| skip = len(code); emit(0) |
| emit(av[0]) |
| emit(av[1]) |
| _compile(code, av[2], flags) |
| emit(OPCODES[SUCCESS]) |
| code[skip] = len(code) - skip |
| else: |
| lo, hi = av[2].getwidth() |
| if lo == 0: |
| raise error, "nothing to repeat" |
| if 0 and lo == hi == 1 and op is MAX_REPEAT: |
| # FIXME: <fl> need a better way to figure out when |
| # it's safe to use this one (in the parser, probably) |
| emit(OPCODES[MAX_REPEAT_ONE]) |
| skip = len(code); emit(0) |
| emit(av[0]) |
| emit(av[1]) |
| _compile(code, av[2], flags) |
| emit(OPCODES[SUCCESS]) |
| code[skip] = len(code) - skip |
| else: |
| emit(OPCODES[op]) |
| skip = len(code); emit(0) |
| emit(av[0]) |
| emit(av[1]) |
| mark = MAXCODE |
| if av[2][0][0] == SUBPATTERN: |
| # repeated subpattern |
| gid, foo = av[2][0][1] |
| if gid: |
| mark = (gid-1)*2 |
| emit(mark) |
| _compile(code, av[2], flags) |
| emit(OPCODES[SUCCESS]) |
| code[skip] = len(code) - skip |
| elif op is SUBPATTERN: |
| gid = av[0] |
| if gid: |
| emit(OPCODES[MARK]) |
| emit((gid-1)*2) |
| _compile(code, av[1], flags) |
| if gid: |
| emit(OPCODES[MARK]) |
| emit((gid-1)*2+1) |
| elif op in (SUCCESS, FAILURE): |
| emit(OPCODES[op]) |
| elif op in (ASSERT, ASSERT_NOT): |
| emit(OPCODES[op]) |
| skip = len(code); emit(0) |
| if av[0] >= 0: |
| emit(0) # look ahead |
| else: |
| lo, hi = av[1].getwidth() |
| if lo != hi: |
| raise error, "look-behind requires fixed-width pattern" |
| emit(lo) # look behind |
| _compile(code, av[1], flags) |
| emit(OPCODES[SUCCESS]) |
| code[skip] = len(code) - skip |
| elif op is CALL: |
| emit(OPCODES[op]) |
| skip = len(code); emit(0) |
| _compile(code, av, flags) |
| emit(OPCODES[SUCCESS]) |
| code[skip] = len(code) - skip |
| elif op is AT: |
| emit(OPCODES[op]) |
| if flags & SRE_FLAG_MULTILINE: |
| emit(ATCODES[AT_MULTILINE.get(av, av)]) |
| else: |
| emit(ATCODES[av]) |
| elif op is BRANCH: |
| emit(OPCODES[op]) |
| tail = [] |
| for av in av[1]: |
| skip = len(code); emit(0) |
| _compile(code, av, flags) |
| emit(OPCODES[JUMP]) |
| tail.append(len(code)); emit(0) |
| code[skip] = len(code) - skip |
| emit(0) # end of branch |
| for tail in tail: |
| code[tail] = len(code) - tail |
| elif op is CATEGORY: |
| emit(OPCODES[op]) |
| if flags & SRE_FLAG_LOCALE: |
| emit(CHCODES[CH_LOCALE[av]]) |
| elif flags & SRE_FLAG_UNICODE: |
| emit(CHCODES[CH_UNICODE[av]]) |
| else: |
| emit(CHCODES[av]) |
| elif op is GROUPREF: |
| if flags & SRE_FLAG_IGNORECASE: |
| emit(OPCODES[OP_IGNORE[op]]) |
| else: |
| emit(OPCODES[op]) |
| emit(av-1) |
| elif op in (MARK, INDEX): |
| emit(OPCODES[op]) |
| emit(av) |
| else: |
| raise ValueError, ("unsupported operand type", op) |
| |
| def _compile_info(code, pattern, flags): |
| # internal: compile an info block. in the current version, |
| # this contains min/max pattern width, and an optional literal |
| # prefix or a character map |
| lo, hi = pattern.getwidth() |
| if lo == 0: |
| return # not worth it |
| # look for a literal prefix |
| prefix = [] |
| charset = [] # not used |
| if not (flags & SRE_FLAG_IGNORECASE): |
| for op, av in pattern.data: |
| if op is LITERAL: |
| prefix.append(av) |
| else: |
| break |
| # add an info block |
| emit = code.append |
| emit(OPCODES[INFO]) |
| skip = len(code); emit(0) |
| # literal flag |
| mask = 0 |
| if prefix: |
| mask = SRE_INFO_PREFIX |
| if len(prefix) == len(pattern.data): |
| mask = mask + SRE_INFO_LITERAL |
| elif charset: |
| mask = mask + SRE_INFO_CHARSET |
| emit(mask) |
| # pattern length |
| if lo < MAXCODE: |
| emit(lo) |
| else: |
| emit(MAXCODE) |
| prefix = prefix[:MAXCODE] |
| if hi < MAXCODE: |
| emit(hi) |
| else: |
| emit(0) |
| # add literal prefix |
| if prefix: |
| emit(len(prefix)) |
| if prefix: |
| code.extend(prefix) |
| # generate overlap table |
| table = [-1] + ([0]*len(prefix)) |
| for i in range(len(prefix)): |
| table[i+1] = table[i]+1 |
| while table[i+1] > 0 and prefix[i] != prefix[table[i+1]-1]: |
| table[i+1] = table[table[i+1]-1]+1 |
| code.extend(table[1:]) # don't store first entry |
| elif charset: |
| for char in charset: |
| emit(OPCODES[LITERAL]) |
| emit(char) |
| emit(OPCODES[FAILURE]) |
| code[skip] = len(code) - skip |
| |
| def compile(p, flags=0): |
| # internal: convert pattern list to internal format |
| |
| # compile, as necessary |
| if type(p) in (type(""), type(u"")): |
| import sre_parse |
| pattern = p |
| p = sre_parse.parse(p, flags) |
| else: |
| pattern = None |
| |
| flags = p.pattern.flags | flags |
| code = [] |
| |
| # compile info block |
| _compile_info(code, p, flags) |
| |
| # compile the pattern |
| _compile(code, p.data, flags) |
| |
| code.append(OPCODES[SUCCESS]) |
| |
| # FIXME: <fl> get rid of this limitation! |
| assert p.pattern.groups <= 100,\ |
| "sorry, but this version only supports 100 named groups" |
| |
| # map in either direction |
| groupindex = p.pattern.groupdict |
| indexgroup = [None] * p.pattern.groups |
| for k, i in groupindex.items(): |
| indexgroup[i] = k |
| |
| return _sre.compile( |
| pattern, flags, code, |
| p.pattern.groups-1, |
| groupindex, indexgroup |
| ) |