# | |
# 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 | |
def _identityfunction(x): | |
return x | |
_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]) | |
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 | |
for op, av in pattern: | |
if op in LITERAL_CODES: | |
if flags & SRE_FLAG_IGNORECASE: | |
emit(OPCODES[OP_IGNORE[op]]) | |
emit(_sre.getlower(av, flags)) | |
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 = _identityfunction | |
skip = _len(code); emit(0) | |
_compile_charset(av, flags, code, fixup) | |
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): | |
# compile charset subprogram | |
emit = code.append | |
if fixup is None: | |
fixup = _identityfunction | |
for op, av in _optimize_charset(charset, 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 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): | |
# internal: optimize character set | |
out = [] | |
outappend = out.append | |
charmap = [0]*256 | |
try: | |
for op, av in charset: | |
if op is NEGATE: | |
outappend((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: | |
# XXX: could append to charmap tail | |
return charset # cannot compress | |
except IndexError: | |
# character set contains unicode characters | |
return _optimize_unicode(charset, fixup) | |
# compress character map | |
i = p = n = 0 | |
runs = [] | |
runsappend = runs.append | |
for c in charmap: | |
if c: | |
if n == 0: | |
p = i | |
n = n + 1 | |
elif n: | |
runsappend((p, n)) | |
n = 0 | |
i = i + 1 | |
if n: | |
runsappend((p, n)) | |
if len(runs) <= 2: | |
# use literal/range | |
for p, n in runs: | |
if n == 1: | |
outappend((LITERAL, p)) | |
else: | |
outappend((RANGE, (p, p+n-1))) | |
if len(out) < len(charset): | |
return out | |
else: | |
# use bitmap | |
data = _mk_bitmap(charmap) | |
outappend((CHARSET, data)) | |
return out | |
return charset | |
def _mk_bitmap(bits): | |
data = [] | |
dataappend = data.append | |
if _sre.CODESIZE == 2: | |
start = (1, 0) | |
else: | |
start = (1L, 0L) | |
m, v = start | |
for c in bits: | |
if c: | |
v = v + m | |
m = m + m | |
if m > MAXCODE: | |
dataappend(v) | |
m, v = start | |
return data | |
# 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 16-bit word sequence, consisting of one word for | |
# the number of different chunks, a sequence of 256 bytes (128 words) | |
# of chunk numbers indexed by their original chunk position, and a | |
# sequence of chunks (16 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 UTF-16 has not yet been developed. This means, | |
# in particular, that negated charsets cannot be represented as | |
# bigcharsets. | |
def _optimize_unicode(charset, fixup): | |
try: | |
import array | |
except ImportError: | |
return charset | |
charmap = [0]*65536 | |
negate = 0 | |
try: | |
for op, av in charset: | |
if op is NEGATE: | |
negate = 1 | |
elif op is LITERAL: | |
charmap[fixup(av)] = 1 | |
elif op is RANGE: | |
for i in xrange(fixup(av[0]), fixup(av[1])+1): | |
charmap[i] = 1 | |
elif op is CATEGORY: | |
# XXX: could expand category | |
return charset # cannot compress | |
except IndexError: | |
# non-BMP characters | |
return charset | |
if negate: | |
if sys.maxunicode != 65535: | |
# XXX: negation does not work with big charsets | |
return charset | |
for i in xrange(65536): | |
charmap[i] = not charmap[i] | |
comps = {} | |
mapping = [0]*256 | |
block = 0 | |
data = [] | |
for i in xrange(256): | |
chunk = tuple(charmap[i*256:(i+1)*256]) | |
new = comps.setdefault(chunk, block) | |
mapping[i] = new | |
if new == block: | |
block = block + 1 | |
data = data + _mk_bitmap(chunk) | |
header = [block] | |
if _sre.CODESIZE == 2: | |
code = 'H' | |
else: | |
code = 'I' | |
# Convert block indices to byte array of 256 bytes | |
mapping = array.array('b', mapping).tostring() | |
# Convert byte array to word array | |
mapping = array.array(code, mapping) | |
assert mapping.itemsize == _sre.CODESIZE | |
header = header + mapping.tolist() | |
data[0:0] = header | |
return [(BIGCHARSET, data)] | |
def _simple(av): | |
# check if av is a "simple" operator | |
lo, hi = av[2].getwidth() | |
if lo == 0 and hi == MAXREPEAT: | |
raise error, "nothing to repeat" | |
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 lo == 0: | |
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 | |
) |