Function _compile_info

Lib/re/_compiler.py:525–585

(code, pattern, flags)

    return None

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 hi > MAXCODE:
        hi = MAXCODE
    if lo == 0:
        code.extend([INFO, 4, 0, lo, hi])
        return
    # look for a literal prefix
    prefix = []
    prefix_skip = 0
    charset = None # not used
    if not (flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE):
        # look for literal prefix
        prefix, prefix_skip, got_all = _get_literal_prefix(pattern, flags)
        # if no prefix, look for charset prefix
        if not prefix:
            charset = _get_charset_prefix(pattern, flags)
            if charset:
                charset, hascased = _optimize_charset(charset)
                assert not hascased
                if charset == _CHARSET_ALL:
                    charset = None
##     if prefix:
##         print("*** PREFIX", prefix, prefix_skip)
##     if charset:
##         print("*** CHARSET", charset)
    # add an info block
    emit = code.append
    emit(INFO)
    skip = len(code); emit(0)
    # literal flag
    mask = 0
    if prefix:
        mask = SRE_INFO_PREFIX
        if prefix_skip is None and got_all:
            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]
    emit(hi)
    # add literal prefix
    if prefix:
        emit(len(prefix)) # length
        if prefix_skip is None:
            prefix_skip =  len(prefix)
        emit(prefix_skip) # skip
        code.extend(prefix)
        # generate overlap table
        code.extend(_generate_overlap_table(prefix))