~pythoneers/ubuntu/lucid/python2.7/ltsppa.ctypes : contents of Lib/sre

~pythoneers/ubuntu/lucid/python2.7/ltsppa.ctypes : (revision 59)

#
# Secret Labs' Regular Expression Engine
#
# convert re-style regular expression to sre pattern
#
# Copyright (c) 1998-2001 by Secret Labs AB.  All rights reserved.
#
# See the sre.py file for information on usage and redistribution.
#

"""Internal support module for sre"""

# XXX: show string offset and offending character for all errors

import sys

from sre_constants import *

SPECIAL_CHARS = ".\\[{()*+?^$|"
REPEAT_CHARS = "*+?{"

DIGITS = set("0123456789")

OCTDIGITS = set("01234567")
HEXDIGITS = set("0123456789abcdefABCDEF")

WHITESPACE = set(" \t\n\r\v\f")

ESCAPES = {
    r"\a": (LITERAL, ord("\a")),
    r"\b": (LITERAL, ord("\b")),
    r"\f": (LITERAL, ord("\f")),
    r"\n": (LITERAL, ord("\n")),
    r"\r": (LITERAL, ord("\r")),
    r"\t": (LITERAL, ord("\t")),
    r"\v": (LITERAL, ord("\v")),
    r"\\": (LITERAL, ord("\\"))
}

CATEGORIES = {
    r"\A": (AT, AT_BEGINNING_STRING), # start of string
    r"\b": (AT, AT_BOUNDARY),
    r"\B": (AT, AT_NON_BOUNDARY),
    r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
    r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
    r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
    r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
    r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
    r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
    r"\Z": (AT, AT_END_STRING), # end of string
}

FLAGS = {
    # standard flags
    "i": SRE_FLAG_IGNORECASE,
    "L": SRE_FLAG_LOCALE,
    "m": SRE_FLAG_MULTILINE,
    "s": SRE_FLAG_DOTALL,
    "x": SRE_FLAG_VERBOSE,
    # extensions
    "t": SRE_FLAG_TEMPLATE,
    "u": SRE_FLAG_UNICODE,
}

class Pattern:
    # master pattern object.  keeps track of global attributes
    def __init__(self):
        self.flags = 0
        self.open = []
        self.groups = 1
        self.groupdict = {}
    def opengroup(self, name=None):
        gid = self.groups
        self.groups = gid + 1
        if name is not None:
            ogid = self.groupdict.get(name, None)
            if ogid is not None:
                raise error, ("redefinition of group name %s as group %d; "
                              "was group %d" % (repr(name), gid,  ogid))
            self.groupdict[name] = gid
        self.open.append(gid)
        return gid
    def closegroup(self, gid):
        self.open.remove(gid)
    def checkgroup(self, gid):
        return gid < self.groups and gid not in self.open

class SubPattern:
    # a subpattern, in intermediate form
    def __init__(self, pattern, data=None):
        self.pattern = pattern
        if data is None:
            data = []
        self.data = data
        self.width = None
    def dump(self, level=0):
        nl = 1
        seqtypes = type(()), type([])
        for op, av in self.data:
            print level*"  " + op,; nl = 0
            if op == "in":
                # member sublanguage
                print; nl = 1
                for op, a in av:
                    print (level+1)*"  " + op, a
            elif op == "branch":
                print; nl = 1
                i = 0
                for a in av[1]:
                    if i > 0:
                        print level*"  " + "or"
                    a.dump(level+1); nl = 1
                    i = i + 1
            elif type(av) in seqtypes:
                for a in av:
                    if isinstance(a, SubPattern):
                        if not nl: print
                        a.dump(level+1); nl = 1
                    else:
                        print a, ; nl = 0
            else:
                print av, ; nl = 0
            if not nl: print
    def __repr__(self):
        return repr(self.data)
    def __len__(self):
        return len(self.data)
    def __delitem__(self, index):
        del self.data[index]
    def __getitem__(self, index):
        if isinstance(index, slice):
            return SubPattern(self.pattern, self.data[index])
        return self.data[index]
    def __setitem__(self, index, code):
        self.data[index] = code
    def insert(self, index, code):
        self.data.insert(index, code)
    def append(self, code):
        self.data.append(code)
    def getwidth(self):
        # determine the width (min, max) for this subpattern
        if self.width:
            return self.width
        lo = hi = 0L
        UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY)
        REPEATCODES = (MIN_REPEAT, MAX_REPEAT)
        for op, av in self.data:
            if op is BRANCH:
                i = sys.maxint
                j = 0
                for av in av[1]:
                    l, h = av.getwidth()
                    i = min(i, l)
                    j = max(j, h)
                lo = lo + i
                hi = hi + j
            elif op is CALL:
                i, j = av.getwidth()
                lo = lo + i
                hi = hi + j
            elif op is SUBPATTERN:
                i, j = av[1].getwidth()
                lo = lo + i
                hi = hi + j
            elif op in REPEATCODES:
                i, j = av[2].getwidth()
                lo = lo + long(i) * av[0]
                hi = hi + long(j) * av[1]
            elif op in UNITCODES:
                lo = lo + 1
                hi = hi + 1
            elif op == SUCCESS:
                break
        self.width = int(min(lo, sys.maxint)), int(min(hi, sys.maxint))
        return self.width

class Tokenizer:
    def __init__(self, string):
        self.string = string
        self.index = 0
        self.__next()
    def __next(self):
        if self.index >= len(self.string):
            self.next = None
            return
        char = self.string[self.index]
        if char[0] == "\\":
            try:
                c = self.string[self.index + 1]
            except IndexError:
                raise error, "bogus escape (end of line)"
            char = char + c
        self.index = self.index + len(char)
        self.next = char
    def match(self, char, skip=1):
        if char == self.next:
            if skip:
                self.__next()
            return 1
        return 0
    def get(self):
        this = self.next
        self.__next()
        return this
    def tell(self):
        return self.index, self.next
    def seek(self, index):
        self.index, self.next = index

def isident(char):
    return "a" <= char <= "z" or "A" <= char <= "Z" or char == "_"

def isdigit(char):
    return "0" <= char <= "9"

def isname(name):
    # check that group name is a valid string
    if not isident(name[0]):
        return False
    for char in name[1:]:
        if not isident(char) and not isdigit(char):
            return False
    return True

def _class_escape(source, escape):
    # handle escape code inside character class
    code = ESCAPES.get(escape)
    if code:
        return code
    code = CATEGORIES.get(escape)
    if code:
        return code
    try:
        c = escape[1:2]
        if c == "x":
            # hexadecimal escape (exactly two digits)
            while source.next in HEXDIGITS and len(escape) < 4:
                escape = escape + source.get()
            escape = escape[2:]
            if len(escape) != 2:
                raise error, "bogus escape: %s" % repr("\\" + escape)
            return LITERAL, int(escape, 16) & 0xff
        elif c in OCTDIGITS:
            # octal escape (up to three digits)
            while source.next in OCTDIGITS and len(escape) < 4:
                escape = escape + source.get()
            escape = escape[1:]
            return LITERAL, int(escape, 8) & 0xff
        elif c in DIGITS:
            raise error, "bogus escape: %s" % repr(escape)
        if len(escape) == 2:
            return LITERAL, ord(escape[1])
    except ValueError:
        pass
    raise error, "bogus escape: %s" % repr(escape)

def _escape(source, escape, state):
    # handle escape code in expression
    code = CATEGORIES.get(escape)
    if code:
        return code
    code = ESCAPES.get(escape)
    if code:
        return code
    try:
        c = escape[1:2]
        if c == "x":
            # hexadecimal escape
            while source.next in HEXDIGITS and len(escape) < 4:
                escape = escape + source.get()
            if len(escape) != 4:
                raise ValueError
            return LITERAL, int(escape[2:], 16) & 0xff
        elif c == "0":
            # octal escape
            while source.next in OCTDIGITS and len(escape) < 4:
                escape = escape + source.get()
            return LITERAL, int(escape[1:], 8) & 0xff
        elif c in DIGITS:
            # octal escape *or* decimal group reference (sigh)
            if source.next in DIGITS:
                escape = escape + source.get()
                if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and
                    source.next in OCTDIGITS):
                    # got three octal digits; this is an octal escape
                    escape = escape + source.get()
                    return LITERAL, int(escape[1:], 8) & 0xff
            # not an octal escape, so this is a group reference
            group = int(escape[1:])
            if group < state.groups:
                if not state.checkgroup(group):
                    raise error, "cannot refer to open group"
                return GROUPREF, group
            raise ValueError
        if len(escape) == 2:
            return LITERAL, ord(escape[1])
    except ValueError:
        pass
    raise error, "bogus escape: %s" % repr(escape)

def _parse_sub(source, state, nested=1):
    # parse an alternation: a|b|c

    items = []
    itemsappend = items.append
    sourcematch = source.match
    while 1:
        itemsappend(_parse(source, state))
        if sourcematch("|"):
            continue
        if not nested:
            break
        if not source.next or sourcematch(")", 0):
            break
        else:
            raise error, "pattern not properly closed"

    if len(items) == 1:
        return items[0]

    subpattern = SubPattern(state)
    subpatternappend = subpattern.append

    # check if all items share a common prefix
    while 1:
        prefix = None
        for item in items:
            if not item:
                break
            if prefix is None:
                prefix = item[0]
            elif item[0] != prefix:
                break
        else:
            # all subitems start with a common "prefix".
            # move it out of the branch
            for item in items:
                del item[0]
            subpatternappend(prefix)
            continue # check next one
        break

    # check if the branch can be replaced by a character set
    for item in items:
        if len(item) != 1 or item[0][0] != LITERAL:
            break
    else:
        # we can store this as a character set instead of a
        # branch (the compiler may optimize this even more)
        set = []
        setappend = set.append
        for item in items:
            setappend(item[0])
        subpatternappend((IN, set))
        return subpattern

    subpattern.append((BRANCH, (None, items)))
    return subpattern

def _parse_sub_cond(source, state, condgroup):
    item_yes = _parse(source, state)
    if source.match("|"):
        item_no = _parse(source, state)
        if source.match("|"):
            raise error, "conditional backref with more than two branches"
    else:
        item_no = None
    if source.next and not source.match(")", 0):
        raise error, "pattern not properly closed"
    subpattern = SubPattern(state)
    subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
    return subpattern

_PATTERNENDERS = set("|)")
_ASSERTCHARS = set("=!<")
_LOOKBEHINDASSERTCHARS = set("=!")
_REPEATCODES = set([MIN_REPEAT, MAX_REPEAT])

def _parse(source, state):
    # parse a simple pattern
    subpattern = SubPattern(state)

    # precompute constants into local variables
    subpatternappend = subpattern.append
    sourceget = source.get
    sourcematch = source.match
    _len = len
    PATTERNENDERS = _PATTERNENDERS
    ASSERTCHARS = _ASSERTCHARS
    LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS
    REPEATCODES = _REPEATCODES

    while 1:

        if source.next in PATTERNENDERS:
            break # end of subpattern
        this = sourceget()
        if this is None:
            break # end of pattern

        if state.flags & SRE_FLAG_VERBOSE:
            # skip whitespace and comments
            if this in WHITESPACE:
                continue
            if this == "#":
                while 1:
                    this = sourceget()
                    if this in (None, "\n"):
                        break
                continue

        if this and this[0] not in SPECIAL_CHARS:
            subpatternappend((LITERAL, ord(this)))

        elif this == "[":
            # character set
            set = []
            setappend = set.append
##          if sourcematch(":"):
##              pass # handle character classes
            if sourcematch("^"):
                setappend((NEGATE, None))
            # check remaining characters
            start = set[:]
            while 1:
                this = sourceget()
                if this == "]" and set != start:
                    break
                elif this and this[0] == "\\":
                    code1 = _class_escape(source, this)
                elif this:
                    code1 = LITERAL, ord(this)
                else:
                    raise error, "unexpected end of regular expression"
                if sourcematch("-"):
                    # potential range
                    this = sourceget()
                    if this == "]":
                        if code1[0] is IN:
                            code1 = code1[1][0]
                        setappend(code1)
                        setappend((LITERAL, ord("-")))
                        break
                    elif this:
                        if this[0] == "\\":
                            code2 = _class_escape(source, this)
                        else:
                            code2 = LITERAL, ord(this)
                        if code1[0] != LITERAL or code2[0] != LITERAL:
                            raise error, "bad character range"
                        lo = code1[1]
                        hi = code2[1]
                        if hi < lo:
                            raise error, "bad character range"
                        setappend((RANGE, (lo, hi)))
                    else:
                        raise error, "unexpected end of regular expression"
                else:
                    if code1[0] is IN:
                        code1 = code1[1][0]
                    setappend(code1)

            # XXX: <fl> should move set optimization to compiler!
            if _len(set)==1 and set[0][0] is LITERAL:
                subpatternappend(set[0]) # optimization
            elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:
                subpatternappend((NOT_LITERAL, set[1][1])) # optimization
            else:
                # XXX: <fl> should add charmap optimization here
                subpatternappend((IN, set))

        elif this and this[0] in REPEAT_CHARS:
            # repeat previous item
            if this == "?":
                min, max = 0, 1
            elif this == "*":
                min, max = 0, MAXREPEAT

            elif this == "+":
                min, max = 1, MAXREPEAT
            elif this == "{":
                if source.next == "}":
                    subpatternappend((LITERAL, ord(this)))
                    continue
                here = source.tell()
                min, max = 0, MAXREPEAT
                lo = hi = ""
                while source.next in DIGITS:
                    lo = lo + source.get()
                if sourcematch(","):
                    while source.next in DIGITS:
                        hi = hi + sourceget()
                else:
                    hi = lo
                if not sourcematch("}"):
                    subpatternappend((LITERAL, ord(this)))
                    source.seek(here)
                    continue
                if lo:
                    min = int(lo)
                if hi:
                    max = int(hi)
                if max < min:
                    raise error, "bad repeat interval"
            else:
                raise error, "not supported"
            # figure out which item to repeat
            if subpattern:
                item = subpattern[-1:]
            else:
                item = None
            if not item or (_len(item) == 1 and item[0][0] == AT):
                raise error, "nothing to repeat"
            if item[0][0] in REPEATCODES:
                raise error, "multiple repeat"
            if sourcematch("?"):
                subpattern[-1] = (MIN_REPEAT, (min, max, item))
            else:
                subpattern[-1] = (MAX_REPEAT, (min, max, item))

        elif this == ".":
            subpatternappend((ANY, None))

        elif this == "(":
            group = 1
            name = None
            condgroup = None
            if sourcematch("?"):
                group = 0
                # options
                if sourcematch("P"):
                    # python extensions
                    if sourcematch("<"):
                        # named group: skip forward to end of name
                        name = ""
                        while 1:
                            char = sourceget()
                            if char is None:
                                raise error, "unterminated name"
                            if char == ">":
                                break
                            name = name + char
                        group = 1
                        if not isname(name):
                            raise error, "bad character in group name"
                    elif sourcematch("="):
                        # named backreference
                        name = ""
                        while 1:
                            char = sourceget()
                            if char is None:
                                raise error, "unterminated name"
                            if char == ")":
                                break
                            name = name + char
                        if not isname(name):
                            raise error, "bad character in group name"
                        gid = state.groupdict.get(name)
                        if gid is None:
                            raise error, "unknown group name"
                        subpatternappend((GROUPREF, gid))
                        continue
                    else:
                        char = sourceget()
                        if char is None:
                            raise error, "unexpected end of pattern"
                        raise error, "unknown specifier: ?P%s" % char
                elif sourcematch(":"):
                    # non-capturing group
                    group = 2
                elif sourcematch("#"):
                    # comment
                    while 1:
                        if source.next is None or source.next == ")":
                            break
                        sourceget()
                    if not sourcematch(")"):
                        raise error, "unbalanced parenthesis"
                    continue
                elif source.next in ASSERTCHARS:
                    # lookahead assertions
                    char = sourceget()
                    dir = 1
                    if char == "<":
                        if source.next not in LOOKBEHINDASSERTCHARS:
                            raise error, "syntax error"
                        dir = -1 # lookbehind
                        char = sourceget()
                    p = _parse_sub(source, state)
                    if not sourcematch(")"):
                        raise error, "unbalanced parenthesis"
                    if char == "=":
                        subpatternappend((ASSERT, (dir, p)))
                    else:
                        subpatternappend((ASSERT_NOT, (dir, p)))
                    continue
                elif sourcematch("("):
                    # conditional backreference group
                    condname = ""
                    while 1:
                        char = sourceget()
                        if char is None:
                            raise error, "unterminated name"
                        if char == ")":
                            break
                        condname = condname + char
                    group = 2
                    if isname(condname):
                        condgroup = state.groupdict.get(condname)
                        if condgroup is None:
                            raise error, "unknown group name"
                    else:
                        try:
                            condgroup = int(condname)
                        except ValueError:
                            raise error, "bad character in group name"
                else:
                    # flags
                    if not source.next in FLAGS:
                        raise error, "unexpected end of pattern"
                    while source.next in FLAGS:
                        state.flags = state.flags | FLAGS[sourceget()]
            if group:
                # parse group contents
                if group == 2:
                    # anonymous group
                    group = None
                else:
                    group = state.opengroup(name)
                if condgroup:
                    p = _parse_sub_cond(source, state, condgroup)
                else:
                    p = _parse_sub(source, state)
                if not sourcematch(")"):
                    raise error, "unbalanced parenthesis"
                if group is not None:
                    state.closegroup(group)
                subpatternappend((SUBPATTERN, (group, p)))
            else:
                while 1:
                    char = sourceget()
                    if char is None:
                        raise error, "unexpected end of pattern"
                    if char == ")":
                        break
                    raise error, "unknown extension"

        elif this == "^":
            subpatternappend((AT, AT_BEGINNING))

        elif this == "$":
            subpattern.append((AT, AT_END))

        elif this and this[0] == "\\":
            code = _escape(source, this, state)
            subpatternappend(code)

        else:
            raise error, "parser error"

    return subpattern

def parse(str, flags=0, pattern=None):
    # parse 're' pattern into list of (opcode, argument) tuples

    source = Tokenizer(str)

    if pattern is None:
        pattern = Pattern()
    pattern.flags = flags
    pattern.str = str

    p = _parse_sub(source, pattern, 0)

    tail = source.get()
    if tail == ")":
        raise error, "unbalanced parenthesis"
    elif tail:
        raise error, "bogus characters at end of regular expression"

    if flags & SRE_FLAG_DEBUG:
        p.dump()

    if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE:
        # the VERBOSE flag was switched on inside the pattern.  to be
        # on the safe side, we'll parse the whole thing again...
        return parse(str, p.pattern.flags)

    return p

def parse_template(source, pattern):
    # parse 're' replacement string into list of literals and
    # group references
    s = Tokenizer(source)
    sget = s.get
    p = []
    a = p.append
    def literal(literal, p=p, pappend=a):
        if p and p[-1][0] is LITERAL:
            p[-1] = LITERAL, p[-1][1] + literal
        else:
            pappend((LITERAL, literal))
    sep = source[:0]
    if type(sep) is type(""):
        makechar = chr
    else:
        makechar = unichr
    while 1:
        this = sget()
        if this is None:
            break # end of replacement string
        if this and this[0] == "\\":
            # group
            c = this[1:2]
            if c == "g":
                name = ""
                if s.match("<"):
                    while 1:
                        char = sget()
                        if char is None:
                            raise error, "unterminated group name"
                        if char == ">":
                            break
                        name = name + char
                if not name:
                    raise error, "bad group name"
                try:
                    index = int(name)
                    if index < 0:
                        raise error, "negative group number"
                except ValueError:
                    if not isname(name):
                        raise error, "bad character in group name"
                    try:
                        index = pattern.groupindex[name]
                    except KeyError:
                        raise IndexError, "unknown group name"
                a((MARK, index))
            elif c == "0":
                if s.next in OCTDIGITS:
                    this = this + sget()
                    if s.next in OCTDIGITS:
                        this = this + sget()
                literal(makechar(int(this[1:], 8) & 0xff))
            elif c in DIGITS:
                isoctal = False
                if s.next in DIGITS:
                    this = this + sget()
                    if (c in OCTDIGITS and this[2] in OCTDIGITS and
                        s.next in OCTDIGITS):
                        this = this + sget()
                        isoctal = True
                        literal(makechar(int(this[1:], 8) & 0xff))
                if not isoctal:
                    a((MARK, int(this[1:])))
            else:
                try:
                    this = makechar(ESCAPES[this][1])
                except KeyError:
                    pass
                literal(this)
        else:
            literal(this)
    # convert template to groups and literals lists
    i = 0
    groups = []
    groupsappend = groups.append
    literals = [None] * len(p)
    for c, s in p:
        if c is MARK:
            groupsappend((i, s))
            # literal[i] is already None
        else:
            literals[i] = s
        i = i + 1
    return groups, literals

def expand_template(template, match):
    g = match.group
    sep = match.string[:0]
    groups, literals = template
    literals = literals[:]
    try:
        for index, group in groups:
            literals[index] = s = g(group)
            if s is None:
                raise error, "unmatched group"
    except IndexError:
        raise error, "invalid group reference"
    return sep.join(literals)

1 by Matthias Klose Import upstream version 2.7~a2	1	#
	2	# Secret Labs' Regular Expression Engine
	3	#
	4	# convert re-style regular expression to sre pattern
	5	#
	6	# Copyright (c) 1998-2001 by Secret Labs AB. All rights reserved.
	7	#
	8	# See the sre.py file for information on usage and redistribution.
	9	#
	10
	11	"""Internal support module for sre"""
	12
	13	# XXX: show string offset and offending character for all errors
	14
	15	import sys
	16
	17	from sre_constants import *
	18
	19	SPECIAL_CHARS = ".\\[{()*+?^$\|"
	20	REPEAT_CHARS = "*+?{"
	21
	22	DIGITS = set("0123456789")
	23
	24	OCTDIGITS = set("01234567")
	25	HEXDIGITS = set("0123456789abcdefABCDEF")
	26
	27	WHITESPACE = set(" \t\n\r\v\f")
	28
	29	ESCAPES = {
	30	r"\a": (LITERAL, ord("\a")),
	31	r"\b": (LITERAL, ord("\b")),
	32	r"\f": (LITERAL, ord("\f")),
	33	r"\n": (LITERAL, ord("\n")),
	34	r"\r": (LITERAL, ord("\r")),
	35	r"\t": (LITERAL, ord("\t")),
	36	r"\v": (LITERAL, ord("\v")),
	37	r"\\": (LITERAL, ord("\\"))
	38	}
	39
	40	CATEGORIES = {
	41	r"\A": (AT, AT_BEGINNING_STRING), # start of string
	42	r"\b": (AT, AT_BOUNDARY),
	43	r"\B": (AT, AT_NON_BOUNDARY),
	44	r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
	45	r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
	46	r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
	47	r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
	48	r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
	49	r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
	50	r"\Z": (AT, AT_END_STRING), # end of string
	51	}
	52
	53	FLAGS = {
	54	# standard flags
	55	"i": SRE_FLAG_IGNORECASE,
	56	"L": SRE_FLAG_LOCALE,
	57	"m": SRE_FLAG_MULTILINE,
	58	"s": SRE_FLAG_DOTALL,
	59	"x": SRE_FLAG_VERBOSE,
	60	# extensions
	61	"t": SRE_FLAG_TEMPLATE,
	62	"u": SRE_FLAG_UNICODE,
	63	}
	64
65	class Pattern:
66	# master pattern object. keeps track of global attributes
67	def __init__(self):
68	self.flags = 0
69	self.open = []
70	self.groups = 1
71	self.groupdict = {}
72	def opengroup(self, name=None):
73	gid = self.groups
74	self.groups = gid + 1
75	if name is not None:
76	ogid = self.groupdict.get(name, None)
77	if ogid is not None:
78	raise error, ("redefinition of group name %s as group %d; "
79	"was group %d" % (repr(name), gid, ogid))
80	self.groupdict[name] = gid
81	self.open.append(gid)
82	return gid
83	def closegroup(self, gid):
84	self.open.remove(gid)
85	def checkgroup(self, gid):
86	return gid < self.groups and gid not in self.open
87
88	class SubPattern:
89	# a subpattern, in intermediate form
90	def __init__(self, pattern, data=None):
91	self.pattern = pattern
92	if data is None:
93	data = []
94	self.data = data
95	self.width = None
96	def dump(self, level=0):
97	nl = 1
98	seqtypes = type(()), type([])
99	for op, av in self.data:
100	print level*" " + op,; nl = 0
101	if op == "in":
102	# member sublanguage
103	print; nl = 1
104	for op, a in av:
105	print (level+1)*" " + op, a
106	elif op == "branch":
107	print; nl = 1
108	i = 0
109	for a in av[1]:
110	if i > 0:
111	print level*" " + "or"
112	a.dump(level+1); nl = 1
113	i = i + 1
114	elif type(av) in seqtypes:
115	for a in av:
116	if isinstance(a, SubPattern):
117	if not nl: print
118	a.dump(level+1); nl = 1
119	else:
120	print a, ; nl = 0
121	else:
122	print av, ; nl = 0
123	if not nl: print
124	def __repr__(self):
125	return repr(self.data)
126	def __len__(self):
127	return len(self.data)
128	def __delitem__(self, index):
129	del self.data[index]
130	def __getitem__(self, index):
131	if isinstance(index, slice):
132	return SubPattern(self.pattern, self.data[index])
133	return self.data[index]
134	def __setitem__(self, index, code):
135	self.data[index] = code
136	def insert(self, index, code):
137	self.data.insert(index, code)
138	def append(self, code):
139	self.data.append(code)
140	def getwidth(self):
141	# determine the width (min, max) for this subpattern
142	if self.width:
143	return self.width
144	lo = hi = 0L
145	UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY)
146	REPEATCODES = (MIN_REPEAT, MAX_REPEAT)
147	for op, av in self.data:
148	if op is BRANCH:
149	i = sys.maxint
150	j = 0
151	for av in av[1]:
152	l, h = av.getwidth()
153	i = min(i, l)
154	j = max(j, h)
155	lo = lo + i
156	hi = hi + j
157	elif op is CALL:
158	i, j = av.getwidth()
159	lo = lo + i
160	hi = hi + j
161	elif op is SUBPATTERN:
162	i, j = av[1].getwidth()
163	lo = lo + i
164	hi = hi + j
165	elif op in REPEATCODES:
166	i, j = av[2].getwidth()
167	lo = lo + long(i) * av[0]
168	hi = hi + long(j) * av[1]
169	elif op in UNITCODES:
170	lo = lo + 1
171	hi = hi + 1
172	elif op == SUCCESS:
173	break
174	self.width = int(min(lo, sys.maxint)), int(min(hi, sys.maxint))
175	return self.width
176
177	class Tokenizer:
178	def __init__(self, string):
179	self.string = string
180	self.index = 0
181	self.__next()
182	def __next(self):
183	if self.index >= len(self.string):
184	self.next = None
185	return
186	char = self.string[self.index]
187	if char[0] == "\\":
188	try:
189	c = self.string[self.index + 1]
190	except IndexError:
191	raise error, "bogus escape (end of line)"
192	char = char + c
193	self.index = self.index + len(char)
194	self.next = char
195	def match(self, char, skip=1):
196	if char == self.next:
197	if skip:
198	self.__next()
199	return 1
200	return 0
201	def get(self):
202	this = self.next
203	self.__next()
204	return this
205	def tell(self):
206	return self.index, self.next
207	def seek(self, index):
208	self.index, self.next = index
209
210	def isident(char):
211	return "a" <= char <= "z" or "A" <= char <= "Z" or char == "_"
212
213	def isdigit(char):
214	return "0" <= char <= "9"
215
216	def isname(name):
217	# check that group name is a valid string
218	if not isident(name[0]):
219	return False
220	for char in name[1:]:
221	if not isident(char) and not isdigit(char):
222	return False
223	return True
224
225	def _class_escape(source, escape):
226	# handle escape code inside character class
227	code = ESCAPES.get(escape)
228	if code:
229	return code
230	code = CATEGORIES.get(escape)
231	if code:
232	return code
233	try:
234	c = escape[1:2]
235	if c == "x":
236	# hexadecimal escape (exactly two digits)
237	while source.next in HEXDIGITS and len(escape) < 4:
238	escape = escape + source.get()
239	escape = escape[2:]
240	if len(escape) != 2:
241	raise error, "bogus escape: %s" % repr("\\" + escape)
242	return LITERAL, int(escape, 16) & 0xff
243	elif c in OCTDIGITS:
244	# octal escape (up to three digits)
245	while source.next in OCTDIGITS and len(escape) < 4:
246	escape = escape + source.get()
247	escape = escape[1:]
248	return LITERAL, int(escape, 8) & 0xff
249	elif c in DIGITS:
250	raise error, "bogus escape: %s" % repr(escape)
251	if len(escape) == 2:
252	return LITERAL, ord(escape[1])
253	except ValueError:
254	pass
255	raise error, "bogus escape: %s" % repr(escape)
256
257	def _escape(source, escape, state):
258	# handle escape code in expression
259	code = CATEGORIES.get(escape)
260	if code:
261	return code
262	code = ESCAPES.get(escape)
263	if code:
264	return code
265	try:
266	c = escape[1:2]
267	if c == "x":
268	# hexadecimal escape
269	while source.next in HEXDIGITS and len(escape) < 4:
270	escape = escape + source.get()
271	if len(escape) != 4:
272	raise ValueError
273	return LITERAL, int(escape[2:], 16) & 0xff
274	elif c == "0":
275	# octal escape
276	while source.next in OCTDIGITS and len(escape) < 4:
277	escape = escape + source.get()
278	return LITERAL, int(escape[1:], 8) & 0xff
279	elif c in DIGITS:
280	# octal escape or decimal group reference (sigh)
281	if source.next in DIGITS:
282	escape = escape + source.get()
283	if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and
284	source.next in OCTDIGITS):
285	# got three octal digits; this is an octal escape
286	escape = escape + source.get()
287	return LITERAL, int(escape[1:], 8) & 0xff
288	# not an octal escape, so this is a group reference
289	group = int(escape[1:])
290	if group < state.groups:
291	if not state.checkgroup(group):
292	raise error, "cannot refer to open group"
293	return GROUPREF, group
294	raise ValueError
295	if len(escape) == 2:
296	return LITERAL, ord(escape[1])
297	except ValueError:
298	pass
299	raise error, "bogus escape: %s" % repr(escape)
300
301	def _parse_sub(source, state, nested=1):
302	# parse an alternation: a\|b\|c
303
304	items = []
305	itemsappend = items.append
306	sourcematch = source.match
307	while 1:
308	itemsappend(_parse(source, state))
309	if sourcematch("\|"):
310	continue
311	if not nested:
312	break
313	if not source.next or sourcematch(")", 0):
314	break
315	else:
316	raise error, "pattern not properly closed"
317
318	if len(items) == 1:
319	return items[0]
320
321	subpattern = SubPattern(state)
322	subpatternappend = subpattern.append
323
324	# check if all items share a common prefix
325	while 1:
326	prefix = None
327	for item in items:
328	if not item:
329	break
330	if prefix is None:
331	prefix = item[0]
332	elif item[0] != prefix:
333	break
334	else:
335	# all subitems start with a common "prefix".
336	# move it out of the branch
337	for item in items:
338	del item[0]
339	subpatternappend(prefix)
340	continue # check next one
341	break
342
343	# check if the branch can be replaced by a character set
344	for item in items:
345	if len(item) != 1 or item[0][0] != LITERAL:
346	break
347	else:
348	# we can store this as a character set instead of a
349	# branch (the compiler may optimize this even more)
350	set = []
351	setappend = set.append
352	for item in items:
353	setappend(item[0])
354	subpatternappend((IN, set))
355	return subpattern
356
357	subpattern.append((BRANCH, (None, items)))
358	return subpattern
359
360	def _parse_sub_cond(source, state, condgroup):
361	item_yes = _parse(source, state)
362	if source.match("\|"):
363	item_no = _parse(source, state)
364	if source.match("\|"):
365	raise error, "conditional backref with more than two branches"
366	else:
367	item_no = None
368	if source.next and not source.match(")", 0):
369	raise error, "pattern not properly closed"
370	subpattern = SubPattern(state)
371	subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
372	return subpattern
373
374	_PATTERNENDERS = set("\|)")
375	_ASSERTCHARS = set("=!<")
376	_LOOKBEHINDASSERTCHARS = set("=!")
377	_REPEATCODES = set([MIN_REPEAT, MAX_REPEAT])
378
379	def _parse(source, state):
380	# parse a simple pattern
381	subpattern = SubPattern(state)
382
383	# precompute constants into local variables
384	subpatternappend = subpattern.append
385	sourceget = source.get
386	sourcematch = source.match
387	_len = len
388	PATTERNENDERS = _PATTERNENDERS
389	ASSERTCHARS = _ASSERTCHARS
390	LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS
391	REPEATCODES = _REPEATCODES
392
393	while 1:
394
395	if source.next in PATTERNENDERS:
396	break # end of subpattern
397	this = sourceget()
398	if this is None:
399	break # end of pattern
400
401	if state.flags & SRE_FLAG_VERBOSE:
402	# skip whitespace and comments
403	if this in WHITESPACE:
404	continue
405	if this == "#":
406	while 1:
407	this = sourceget()
408	if this in (None, "\n"):
409	break
410	continue
411
412	if this and this[0] not in SPECIAL_CHARS:
413	subpatternappend((LITERAL, ord(this)))
414
415	elif this == "[":
416	# character set
417	set = []
418	setappend = set.append
419	## if sourcematch(":"):
420	## pass # handle character classes
421	if sourcematch("^"):
422	setappend((NEGATE, None))
423	# check remaining characters
424	start = set[:]
425	while 1:
426	this = sourceget()
427	if this == "]" and set != start:
428	break
429	elif this and this[0] == "\\":
430	code1 = _class_escape(source, this)
431	elif this:
432	code1 = LITERAL, ord(this)
433	else:
434	raise error, "unexpected end of regular expression"
435	if sourcematch("-"):
436	# potential range
437	this = sourceget()
438	if this == "]":
439	if code1[0] is IN:
440	code1 = code1[1][0]
441	setappend(code1)
442	setappend((LITERAL, ord("-")))
443	break
444	elif this:
445	if this[0] == "\\":
446	code2 = _class_escape(source, this)
447	else:
448	code2 = LITERAL, ord(this)
449	if code1[0] != LITERAL or code2[0] != LITERAL:
450	raise error, "bad character range"
451	lo = code1[1]
452	hi = code2[1]
453	if hi < lo:
454	raise error, "bad character range"
455	setappend((RANGE, (lo, hi)))
456	else:
457	raise error, "unexpected end of regular expression"
458	else:
459	if code1[0] is IN:
460	code1 = code1[1][0]
461	setappend(code1)
462
463	# XXX: <fl> should move set optimization to compiler!
464	if _len(set)==1 and set[0][0] is LITERAL:
465	subpatternappend(set[0]) # optimization
466	elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:
467	subpatternappend((NOT_LITERAL, set[1][1])) # optimization
468	else:
469	# XXX: <fl> should add charmap optimization here
470	subpatternappend((IN, set))
471
472	elif this and this[0] in REPEAT_CHARS:
473	# repeat previous item
474	if this == "?":
475	min, max = 0, 1
476	elif this == "*":
477	min, max = 0, MAXREPEAT
478
479	elif this == "+":
480	min, max = 1, MAXREPEAT
481	elif this == "{":
482	if source.next == "}":
483	subpatternappend((LITERAL, ord(this)))
484	continue
485	here = source.tell()
486	min, max = 0, MAXREPEAT
487	lo = hi = ""
488	while source.next in DIGITS:
489	lo = lo + source.get()
490	if sourcematch(","):
491	while source.next in DIGITS:
492	hi = hi + sourceget()
493	else:
494	hi = lo
495	if not sourcematch("}"):
496	subpatternappend((LITERAL, ord(this)))
497	source.seek(here)
498	continue
499	if lo:
500	min = int(lo)
501	if hi:
502	max = int(hi)
503	if max < min:
504	raise error, "bad repeat interval"
505	else:
506	raise error, "not supported"
507	# figure out which item to repeat
508	if subpattern:
509	item = subpattern[-1:]
510	else:
511	item = None
512	if not item or (_len(item) == 1 and item[0][0] == AT):
513	raise error, "nothing to repeat"
514	if item[0][0] in REPEATCODES:
515	raise error, "multiple repeat"
516	if sourcematch("?"):
517	subpattern[-1] = (MIN_REPEAT, (min, max, item))
518	else:
519	subpattern[-1] = (MAX_REPEAT, (min, max, item))
520
521	elif this == ".":
522	subpatternappend((ANY, None))
523
524	elif this == "(":
525	group = 1
526	name = None
527	condgroup = None
528	if sourcematch("?"):
529	group = 0
530	# options
531	if sourcematch("P"):
532	# python extensions
533	if sourcematch("<"):
534	# named group: skip forward to end of name
535	name = ""
536	while 1:
537	char = sourceget()
538	if char is None:
539	raise error, "unterminated name"
540	if char == ">":
541	break
542	name = name + char
543	group = 1
544	if not isname(name):
545	raise error, "bad character in group name"
546	elif sourcematch("="):
547	# named backreference
548	name = ""
549	while 1:
550	char = sourceget()
551	if char is None:
552	raise error, "unterminated name"
553	if char == ")":
554	break
555	name = name + char
556	if not isname(name):
557	raise error, "bad character in group name"
558	gid = state.groupdict.get(name)
559	if gid is None:
560	raise error, "unknown group name"
561	subpatternappend((GROUPREF, gid))
562	continue
563	else:
564	char = sourceget()
565	if char is None:
566	raise error, "unexpected end of pattern"
567	raise error, "unknown specifier: ?P%s" % char
568	elif sourcematch(":"):
569	# non-capturing group
570	group = 2
571	elif sourcematch("#"):
572	# comment
573	while 1:
574	if source.next is None or source.next == ")":
575	break
576	sourceget()
577	if not sourcematch(")"):
578	raise error, "unbalanced parenthesis"
579	continue
580	elif source.next in ASSERTCHARS:
581	# lookahead assertions
582	char = sourceget()
583	dir = 1
584	if char == "<":
585	if source.next not in LOOKBEHINDASSERTCHARS:
586	raise error, "syntax error"
587	dir = -1 # lookbehind
588	char = sourceget()
589	p = _parse_sub(source, state)
590	if not sourcematch(")"):
591	raise error, "unbalanced parenthesis"
592	if char == "=":
593	subpatternappend((ASSERT, (dir, p)))
594	else:
595	subpatternappend((ASSERT_NOT, (dir, p)))
596	continue
597	elif sourcematch("("):
598	# conditional backreference group
599	condname = ""
600	while 1:
601	char = sourceget()
602	if char is None:
603	raise error, "unterminated name"
604	if char == ")":
605	break
606	condname = condname + char
607	group = 2
608	if isname(condname):
609	condgroup = state.groupdict.get(condname)
610	if condgroup is None:
611	raise error, "unknown group name"
612	else:
613	try:
614	condgroup = int(condname)
615	except ValueError:
616	raise error, "bad character in group name"
617	else:
618	# flags
619	if not source.next in FLAGS:
620	raise error, "unexpected end of pattern"
621	while source.next in FLAGS:
622	state.flags = state.flags \| FLAGS[sourceget()]
623	if group:
624	# parse group contents
625	if group == 2:
626	# anonymous group
627	group = None
628	else:
629	group = state.opengroup(name)
630	if condgroup:
631	p = _parse_sub_cond(source, state, condgroup)
632	else:
633	p = _parse_sub(source, state)
634	if not sourcematch(")"):
635	raise error, "unbalanced parenthesis"
636	if group is not None:
637	state.closegroup(group)
638	subpatternappend((SUBPATTERN, (group, p)))
639	else:
640	while 1:
641	char = sourceget()
642	if char is None:
643	raise error, "unexpected end of pattern"
644	if char == ")":
645	break
646	raise error, "unknown extension"
647
648	elif this == "^":
649	subpatternappend((AT, AT_BEGINNING))
650
651	elif this == "$":
652	subpattern.append((AT, AT_END))
653
654	elif this and this[0] == "\\":
655	code = _escape(source, this, state)
656	subpatternappend(code)
657
658	else:
659	raise error, "parser error"
660
661	return subpattern
662
663	def parse(str, flags=0, pattern=None):
664	# parse 're' pattern into list of (opcode, argument) tuples
665
666	source = Tokenizer(str)
667
668	if pattern is None:
669	pattern = Pattern()
670	pattern.flags = flags
671	pattern.str = str
672
673	p = _parse_sub(source, pattern, 0)
674
675	tail = source.get()
676	if tail == ")":
677	raise error, "unbalanced parenthesis"
678	elif tail:
679	raise error, "bogus characters at end of regular expression"
680
681	if flags & SRE_FLAG_DEBUG:
682	p.dump()
683
684	if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE:
685	# the VERBOSE flag was switched on inside the pattern. to be
686	# on the safe side, we'll parse the whole thing again...
687	return parse(str, p.pattern.flags)
688
689	return p
690
691	def parse_template(source, pattern):
692	# parse 're' replacement string into list of literals and
693	# group references
694	s = Tokenizer(source)
695	sget = s.get
696	p = []
697	a = p.append
698	def literal(literal, p=p, pappend=a):
699	if p and p[-1][0] is LITERAL:
700	p[-1] = LITERAL, p[-1][1] + literal
701	else:
702	pappend((LITERAL, literal))
703	sep = source[:0]
704	if type(sep) is type(""):
705	makechar = chr
706	else:
707	makechar = unichr
708	while 1:
709	this = sget()
710	if this is None:
711	break # end of replacement string
712	if this and this[0] == "\\":
713	# group
714	c = this[1:2]
715	if c == "g":
716	name = ""
717	if s.match("<"):
718	while 1:
719	char = sget()
720	if char is None:
721	raise error, "unterminated group name"
722	if char == ">":
723	break
724	name = name + char
725	if not name:
726	raise error, "bad group name"
727	try:
728	index = int(name)
729	if index < 0:
730	raise error, "negative group number"
731	except ValueError:
732	if not isname(name):
733	raise error, "bad character in group name"
734	try:
735	index = pattern.groupindex[name]
736	except KeyError:
737	raise IndexError, "unknown group name"
738	a((MARK, index))
739	elif c == "0":
740	if s.next in OCTDIGITS:
741	this = this + sget()
742	if s.next in OCTDIGITS:
743	this = this + sget()
744	literal(makechar(int(this[1:], 8) & 0xff))
745	elif c in DIGITS:
746	isoctal = False
747	if s.next in DIGITS:
748	this = this + sget()
749	if (c in OCTDIGITS and this[2] in OCTDIGITS and
750	s.next in OCTDIGITS):
751	this = this + sget()
752	isoctal = True
753	literal(makechar(int(this[1:], 8) & 0xff))
754	if not isoctal:
755	a((MARK, int(this[1:])))
756	else:
757	try:
758	this = makechar(ESCAPES[this][1])
759	except KeyError:
760	pass
761	literal(this)
762	else:
763	literal(this)
764	# convert template to groups and literals lists
765	i = 0
766	groups = []
767	groupsappend = groups.append
768	literals = [None] * len(p)
769	for c, s in p:
770	if c is MARK:
771	groupsappend((i, s))
772	# literal[i] is already None
773	else:
774	literals[i] = s
775	i = i + 1
776	return groups, literals
777
778	def expand_template(template, match):
779	g = match.group
780	sep = match.string[:0]
781	groups, literals = template
782	literals = literals[:]
783	try:
784	for index, group in groups:
785	literals[index] = s = g(group)
786	if s is None:
787	raise error, "unmatched group"
788	except IndexError:
789	raise error, "invalid group reference"
790	return sep.join(literals)