#
# 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.
#

import _sre

from sre_constants import *

assert _sre.MAGIC == MAGIC, "SRE module mismatch"

MAXCODE = 65535

def _compile(code, pattern, flags):
    # internal: compile a (sub)pattern
    emit = code.append
    for op, av in pattern:
        if op in (LITERAL, NOT_LITERAL):
            if flags & SRE_FLAG_IGNORECASE:
                emit(OPCODES[OP_IGNORE[op]])
                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 = lambda x: x
            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 (REPEAT, MIN_REPEAT, MAX_REPEAT):
            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 == MAX_REPEAT:
                emit(OPCODES[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 == 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, FAILURE):
            emit(OPCODES[op])
        elif op in (ASSERT, ASSERT_NOT):
            emit(OPCODES[op])
            skip = len(code); emit(0)
            if av[0] >= 0:
                emit(0) # look ahead
            else:
                lo, hi = av[1].getwidth()
                if lo != hi:
                    raise error, "look-behind requires fixed-width pattern"
                emit(lo) # look behind
            _compile(code, av[1], flags)
            emit(OPCODES[SUCCESS])
            code[skip] = len(code) - skip
        elif op is CALL:
            emit(OPCODES[op])
            skip = len(code); emit(0)
            _compile(code, av, flags)
            emit(OPCODES[SUCCESS])
            code[skip] = len(code) - skip
        elif op is AT:
            emit(OPCODES[op])
            if flags & SRE_FLAG_MULTILINE:
                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 = []
            for av in av[1]:
                skip = len(code); emit(0)
                # _compile_info(code, av, flags)
                _compile(code, av, flags)
                emit(OPCODES[JUMP])
                tail.append(len(code)); emit(0)
                code[skip] = len(code) - skip
            emit(0) # end of branch
            for tail in tail:
                code[tail] = len(code) - tail
        elif op is CATEGORY:
            emit(OPCODES[op])
            if flags & SRE_FLAG_LOCALE:
                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)
        else:
            raise ValueError, ("unsupported operand type", op)

def _compile_charset(charset, flags, code, fixup=None):
    # compile charset subprogram
    emit = code.append
    if not fixup:
        fixup = lambda x: x
    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 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 = []
    charmap = [0]*256
    try:
        for op, av in charset:
            if op is NEGATE:
                out.append((op, av))
            elif op is LITERAL:
                charmap[fixup(av)] = 1
            elif op is RANGE:
                for i in range(fixup(av[0]), fixup(av[1])+1):
                    charmap[i] = 1
            elif op is CATEGORY:
                # XXX: could append to charmap tail
                return charset # cannot compress
    except IndexError:
        # character set contains unicode characters
        return charset
    # compress character map
    i = p = n = 0
    runs = []
    for c in charmap:
        if c:
            if n == 0:
                p = i
            n = n + 1
        elif n: