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Editing: sre_compile.py
# -*- coding: utf-8 -*- # # Secret Labs' Regular Expression Engine # # convert template to internal format # # Copyright (c) 1997-2001 by Secret Labs AB. All rights reserved. # # See the sre.py file for information on usage and redistribution. # """Internal support module for sre""" import _sre, sys import sre_parse from sre_constants import * assert _sre.MAGIC == MAGIC, "SRE module mismatch" if _sre.CODESIZE == 2: MAXCODE = 65535 else: MAXCODE = 0xFFFFFFFFL _LITERAL_CODES = set([LITERAL, NOT_LITERAL]) _REPEATING_CODES = set([REPEAT, MIN_REPEAT, MAX_REPEAT]) _SUCCESS_CODES = set([SUCCESS, FAILURE]) _ASSERT_CODES = set([ASSERT, ASSERT_NOT]) # Sets of lowercase characters which have the same uppercase. _equivalences = ( # LATIN SMALL LETTER I, LATIN SMALL LETTER DOTLESS I (0x69, 0x131), # iı # LATIN SMALL LETTER S, LATIN SMALL LETTER LONG S (0x73, 0x17f), # sſ # MICRO SIGN, GREEK SMALL LETTER MU (0xb5, 0x3bc), # µμ # COMBINING GREEK YPOGEGRAMMENI, GREEK SMALL LETTER IOTA, GREEK PROSGEGRAMMENI (0x345, 0x3b9, 0x1fbe), # \u0345ιι # GREEK SMALL LETTER BETA, GREEK BETA SYMBOL (0x3b2, 0x3d0), # βϐ # GREEK SMALL LETTER EPSILON, GREEK LUNATE EPSILON SYMBOL (0x3b5, 0x3f5), # εϵ # GREEK SMALL LETTER THETA, GREEK THETA SYMBOL (0x3b8, 0x3d1), # θϑ # GREEK SMALL LETTER KAPPA, GREEK KAPPA SYMBOL (0x3ba, 0x3f0), # κϰ # GREEK SMALL LETTER PI, GREEK PI SYMBOL (0x3c0, 0x3d6), # πϖ # GREEK SMALL LETTER RHO, GREEK RHO SYMBOL (0x3c1, 0x3f1), # ρϱ # GREEK SMALL LETTER FINAL SIGMA, GREEK SMALL LETTER SIGMA (0x3c2, 0x3c3), # ςσ # GREEK SMALL LETTER PHI, GREEK PHI SYMBOL (0x3c6, 0x3d5), # φϕ # LATIN SMALL LETTER S WITH DOT ABOVE, LATIN SMALL LETTER LONG S WITH DOT ABOVE (0x1e61, 0x1e9b), # ṡẛ ) # Maps the lowercase code to lowercase codes which have the same uppercase. _ignorecase_fixes = {i: tuple(j for j in t if i != j) for t in _equivalences for i in t} def _compile(code, pattern, flags): # internal: compile a (sub)pattern emit = code.append _len = len LITERAL_CODES = _LITERAL_CODES REPEATING_CODES = _REPEATING_CODES SUCCESS_CODES = _SUCCESS_CODES ASSERT_CODES = _ASSERT_CODES if (flags & SRE_FLAG_IGNORECASE and not (flags & SRE_FLAG_LOCALE) and flags & SRE_FLAG_UNICODE): fixes = _ignorecase_fixes else: fixes = None for op, av in pattern: if op in LITERAL_CODES: if flags & SRE_FLAG_IGNORECASE: lo = _sre.getlower(av, flags) if fixes and lo in fixes: emit(OPCODES[IN_IGNORE]) skip = _len(code); emit(0) if op is NOT_LITERAL: emit(OPCODES[NEGATE]) for k in (lo,) + fixes[lo]: emit(OPCODES[LITERAL]) emit(k) emit(OPCODES[FAILURE]) code[skip] = _len(code) - skip else: emit(OPCODES[OP_IGNORE[op]]) emit(lo) 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 = None skip = _len(code); emit(0) _compile_charset(av, flags, code, fixup, fixes) code[skip] = _len(code) - skip elif op is ANY: if flags & SRE_FLAG_DOTALL: emit(OPCODES[ANY_ALL]) else: emit(OPCODES[ANY]) elif op in REPEATING_CODES: if flags & SRE_FLAG_TEMPLATE: raise error, "internal: unsupported template operator" 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 elif _simple(av) and op is not REPEAT: if op is MAX_REPEAT: emit(OPCODES[REPEAT_ONE]) else: emit(OPCODES[MIN_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[REPEAT]) skip = _len(code); emit(0) emit(av[0]) emit(av[1]) _compile(code, av[2], flags) code[skip] = _len(code) - skip if op is MAX_REPEAT: emit(OPCODES[MAX_UNTIL]) else: emit(OPCODES[MIN_UNTIL]) elif op is SUBPATTERN: if av[0]: emit(OPCODES[MARK]) emit((av[0]-1)*2) # _compile_info(code, av[1], flags) _compile(code, av[1], flags) if av[0]: emit(OPCODES[MARK]) emit((av[0]-1)*2+1) elif op in SUCCESS_CODES: emit(OPCODES[op]) elif op in ASSERT_CODES: 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: av = AT_MULTILINE.get(av, av) if flags & SRE_FLAG_LOCALE: av = AT_LOCALE.get(av, av) elif flags & SRE_FLAG_UNICODE: av = AT_UNICODE.get(av, av) emit(ATCODES[av]) elif op is BRANCH: emit(OPCODES[op]) tail = [] tailappend = tail.append for av in av[1]: skip = _len(code); emit(0) # _compile_info(code, av, flags) _compile(code, av, flags) emit(OPCODES[JUMP]) tailappend(_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: av = CH_LOCALE[av] elif flags & SRE_FLAG_UNICODE: av = CH_UNICODE[av] 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 is GROUPREF_EXISTS: emit(OPCODES[op]) emit(av[0]-1) skipyes = _len(code); emit(0) _compile(code, av[1], flags) if av[2]: emit(OPCODES[JUMP]) skipno = _len(code); emit(0) code[skipyes] = _len(code) - skipyes + 1 _compile(code, av[2], flags) code[skipno] = _len(code) - skipno else: code[skipyes] = _len(code) - skipyes + 1 else: raise ValueError, ("unsupported operand type", op) def _compile_charset(charset, flags, code, fixup=None, fixes=None): # compile charset subprogram emit = code.append for op, av in _optimize_charset(charset, fixup, fixes, flags & SRE_FLAG_UNICODE): emit(OPCODES[op]) if op is NEGATE: pass elif op is LITERAL: emit(av) elif op is RANGE: emit(av[0]) emit(av[1]) elif op is CHARSET: code.extend(av) elif op is BIGCHARSET: 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]) def _optimize_charset(charset, fixup, fixes, isunicode): # internal: optimize character set out = [] tail = [] charmap = bytearray(256) for op, av in charset: while True: try: if op is LITERAL: if fixup: i = fixup(av) charmap[i] = 1 if fixes and i in fixes: for k in fixes[i]: charmap[k] = 1 else: charmap[av] = 1 elif op is RANGE: r = range(av[0], av[1]+1) if fixup: r = map(fixup, r) if fixup and fixes: for i in r: charmap[i] = 1 if i in fixes: for k in fixes[i]: charmap[k] = 1 else: for i in r: charmap[i] = 1 elif op is NEGATE: out.append((op, av)) else: tail.append((op, av)) except IndexError: if len(charmap) == 256: # character set contains non-UCS1 character codes charmap += b'\0' * 0xff00 continue # character set contains non-BMP character codes if fixup and isunicode and op is RANGE: lo, hi = av ranges = [av] # There are only two ranges of cased astral characters: # 10400-1044F (Deseret) and 118A0-118DF (Warang Citi). _fixup_range(max(0x10000, lo), min(0x11fff, hi), ranges, fixup) for lo, hi in ranges: if lo == hi: tail.append((LITERAL, hi)) else: tail.append((RANGE, (lo, hi))) else: tail.append((op, av)) break # compress character map runs = [] q = 0 while True: p = charmap.find(b'\1', q) if p < 0: break if len(runs) >= 2: runs = None break q = charmap.find(b'\0', p) if q < 0: runs.append((p, len(charmap))) break runs.append((p, q)) if runs is not None: # use literal/range for p, q in runs: if q - p == 1: out.append((LITERAL, p)) else: out.append((RANGE, (p, q - 1))) out += tail # if the case was changed or new representation is more compact if fixup or len(out) < len(charset): return out # else original character set is good enough return charset # use bitmap if len(charmap) == 256: data = _mk_bitmap(charmap) out.append((CHARSET, data)) out += tail return out # To represent a big charset, first a bitmap of all characters in the # set is constructed. Then, this bitmap is sliced into chunks of 256 # characters, duplicate chunks are eliminated, and each chunk is # given a number. In the compiled expression, the charset is # represented by a 32-bit word sequence, consisting of one word for # the number of different chunks, a sequence of 256 bytes (64 words) # of chunk numbers indexed by their original chunk position, and a # sequence of 256-bit chunks (8 words each). # Compression is normally good: in a typical charset, large ranges of # Unicode will be either completely excluded (e.g. if only cyrillic # letters are to be matched), or completely included (e.g. if large # subranges of Kanji match). These ranges will be represented by # chunks of all one-bits or all zero-bits. # Matching can be also done efficiently: the more significant byte of # the Unicode character is an index into the chunk number, and the # less significant byte is a bit index in the chunk (just like the # CHARSET matching). # In UCS-4 mode, the BIGCHARSET opcode still supports only subsets # of the basic multilingual plane; an efficient representation # for all of Unicode has not yet been developed. charmap = bytes(charmap) # should be hashable comps = {} mapping = bytearray(256) block = 0 data = bytearray() for i in range(0, 65536, 256): chunk = charmap[i: i + 256] if chunk in comps: mapping[i // 256] = comps[chunk] else: mapping[i // 256] = comps[chunk] = block block += 1 data += chunk data = _mk_bitmap(data) data[0:0] = [block] + _bytes_to_codes(mapping) out.append((BIGCHARSET, data)) out += tail return out def _fixup_range(lo, hi, ranges, fixup): for i in map(fixup, range(lo, hi+1)): for k, (lo, hi) in enumerate(ranges): if i < lo: if l == lo - 1: ranges[k] = (i, hi) else: ranges.insert(k, (i, i)) break elif i > hi: if i == hi + 1: ranges[k] = (lo, i) break else: break else: ranges.append((i, i)) _CODEBITS = _sre.CODESIZE * 8 _BITS_TRANS = b'0' + b'1' * 255 def _mk_bitmap(bits, _CODEBITS=_CODEBITS, _int=int): s = bytes(bits).translate(_BITS_TRANS)[::-1] return [_int(s[i - _CODEBITS: i], 2) for i in range(len(s), 0, -_CODEBITS)] def _bytes_to_codes(b): # Convert block indices to word array import array if _sre.CODESIZE == 2: code = 'H' else: code = 'I' a = array.array(code, bytes(b)) assert a.itemsize == _sre.CODESIZE assert len(a) * a.itemsize == len(b) return a.tolist() def _simple(av): # check if av is a "simple" operator lo, hi = av[2].getwidth() return lo == hi == 1 and av[2][0][0] != SUBPATTERN 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 not lo and hi: return # not worth it # look for a literal prefix prefix = [] prefixappend = prefix.append prefix_skip = 0 charset = [] # not used charsetappend = charset.append if not (flags & SRE_FLAG_IGNORECASE): # look for literal prefix for op, av in pattern.data: if op is LITERAL: if len(prefix) == prefix_skip: prefix_skip = prefix_skip + 1 prefixappend(av) elif op is SUBPATTERN and len(av[1]) == 1: op, av = av[1][0] if op is LITERAL: prefixappend(av) else: break else: break # if no prefix, look for charset prefix if not prefix and pattern.data: op, av = pattern.data[0] if op is SUBPATTERN and av[1]: op, av = av[1][0] if op is LITERAL: charsetappend((op, av)) elif op is BRANCH: c = [] cappend = c.append for p in av[1]: if not p: break op, av = p[0] if op is LITERAL: cappend((op, av)) else: break else: charset = c elif op is BRANCH: c = [] cappend = c.append for p in av[1]: if not p: break op, av = p[0] if op is LITERAL: cappend((op, av)) else: break else: charset = c elif op is IN: charset = av ## if prefix: ## print "*** PREFIX", prefix, prefix_skip ## if charset: ## print "*** CHARSET", charset # 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) == prefix_skip == 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)) # length emit(prefix_skip) # skip code.extend(prefix) # generate overlap table table = [-1] + ([0]*len(prefix)) for i in xrange(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: _compile_charset(charset, flags, code) code[skip] = len(code) - skip try: unicode except NameError: STRING_TYPES = (type(""),) else: STRING_TYPES = (type(""), type(unicode(""))) def isstring(obj): for tp in STRING_TYPES: if isinstance(obj, tp): return 1 return 0 def _code(p, flags): 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]) return code def compile(p, flags=0): # internal: convert pattern list to internal format if isstring(p): pattern = p p = sre_parse.parse(p, flags) else: pattern = None code = _code(p, flags) # print code # XXX: <fl> get rid of this limitation! if p.pattern.groups > 100: raise AssertionError( "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 | p.pattern.flags, code, p.pattern.groups-1, groupindex, indexgroup )
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