#

# 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

def set(seq):

    s = {}

    for elem in seq:

        s[elem] = 1

    return s

_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,