sre_constants.py

#
# Secret Labs' Regular Expression Engine
#
# various symbols used by the regular expression engine.
# run this script to update the _sre include files!
#
# 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"""

# update when constants are added or removed

MAGIC = 20171005

from _sre import MAXREPEAT, MAXGROUPS

# SRE standard exception (access as sre.error)
# should this really be here?

class error(Exception):
    """Exception raised for invalid regular expressions.

    Attributes:

        msg: The unformatted error message
        pattern: The regular expression pattern
        pos: The index in the pattern where compilation failed (may be None)
        lineno: The line corresponding to pos (may be None)
        colno: The column corresponding to pos (may be None)
    """

    __module__ = 're'

    def __init__(self, msg, pattern=None, pos=None):
        self.msg = msg
        self.pattern = pattern
        self.pos = pos
        if pattern is not None and pos is not None:
            msg = '%s at position %d' % (msg, pos)
            if isinstance(pattern, str):
                newline = '\n'
            else:
                newline = b'\n'
            self.lineno = pattern.count(newline, 0, pos) + 1
            self.colno = pos - pattern.rfind(newline, 0, pos)
            if newline in pattern:
                msg = '%s (line %d, column %d)' % (msg, self.lineno, self.colno)
        else:
            self.lineno = self.colno = None
        super().__init__(msg)


class _NamedIntConstant(int):
    def __new__(cls, value, name):
        self = super(_NamedIntConstant, cls).__new__(cls, value)
        self.name = name
        return self

    def __repr__(self):
        return self.name

MAXREPEAT = _NamedIntConstant(MAXREPEAT, 'MAXREPEAT')

def _makecodes(names):
    names = names.strip().split()
    items = [_NamedIntConstant(i, name) for i, name in enumerate(names)]
    globals().update({item.name: item for item in items})
    return items

# operators
# failure=0 success=1 (just because it looks better that way :-)
OPCODES = _makecodes("""
    FAILURE SUCCESS

    ANY ANY_ALL
    ASSERT ASSERT_NOT
    AT
    BRANCH
    CALL
    CATEGORY
    CHARSET BIGCHARSET
    GROUPREF GROUPREF_EXISTS
    IN
    INFO
    JUMP
    LITERAL
    MARK
    MAX_UNTIL
    MIN_UNTIL
    NOT_LITERAL
    NEGATE
    RANGE
    REPEAT
    REPEAT_ONE
    SUBPATTERN
    MIN_REPEAT_ONE

    GROUPREF_IGNORE
    IN_IGNORE
    LITERAL_IGNORE
    NOT_LITERAL_IGNORE

    GROUPREF_LOC_IGNORE
    IN_LOC_IGNORE
    LITERAL_LOC_IGNORE
    NOT_LITERAL_LOC_IGNORE

    GROUPREF_UNI_IGNORE
    IN_UNI_IGNORE
    LITERAL_UNI_IGNORE
    NOT_LITERAL_UNI_IGNORE
    RANGE_UNI_IGNORE

    MIN_REPEAT MAX_REPEAT
""")
del OPCODES[-2:] # remove MIN_REPEAT and MAX_REPEAT

# positions
ATCODES = _makecodes("""
    AT_BEGINNING AT_BEGINNING_LINE AT_BEGINNING_STRING
    AT_BOUNDARY AT_NON_BOUNDARY
    AT_END AT_END_LINE AT_END_STRING

    AT_LOC_BOUNDARY AT_LOC_NON_BOUNDARY

    AT_UNI_BOUNDARY AT_UNI_NON_BOUNDARY
""")

# categories
CHCODES = _makecodes("""
    CATEGORY_DIGIT CATEGORY_NOT_DIGIT
    CATEGORY_SPACE CATEGORY_NOT_SPACE
    CATEGORY_WORD CATEGORY_NOT_WORD
    CATEGORY_LINEBREAK CATEGORY_NOT_LINEBREAK

    CATEGORY_LOC_WORD CATEGORY_LOC_NOT_WORD

    CATEGORY_UNI_DIGIT CATEGORY_UNI_NOT_DIGIT
    CATEGORY_UNI_SPACE CATEGORY_UNI_NOT_SPACE
    CATEGORY_UNI_WORD CATEGORY_UNI_NOT_WORD
    CATEGORY_UNI_LINEBREAK CATEGORY_UNI_NOT_LINEBREAK
""")


# replacement operations for "ignore case" mode
OP_IGNORE = {
    LITERAL: LITERAL_IGNORE,
    NOT_LITERAL: NOT_LITERAL_IGNORE,
}

OP_LOCALE_IGNORE = {
    LITERAL: LITERAL_LOC_IGNORE,
    NOT_LITERAL: NOT_LITERAL_LOC_IGNORE,
}

OP_UNICODE_IGNORE = {
    LITERAL: LITERAL_UNI_IGNORE,
    NOT_LITERAL: NOT_LITERAL_UNI_IGNORE,
}

AT_MULTILINE = {
    AT_BEGINNING: AT_BEGINNING_LINE,
    AT_END: AT_END_LINE
}

AT_LOCALE = {
    AT_BOUNDARY: AT_LOC_BOUNDARY,
    AT_NON_BOUNDARY: AT_LOC_NON_BOUNDARY
}

AT_UNICODE = {
    AT_BOUNDARY: AT_UNI_BOUNDARY,
    AT_NON_BOUNDARY: AT_UNI_NON_BOUNDARY
}

CH_LOCALE = {
    CATEGORY_DIGIT: CATEGORY_DIGIT,
    CATEGORY_NOT_DIGIT: CATEGORY_NOT_DIGIT,
    CATEGORY_SPACE: CATEGORY_SPACE,
    CATEGORY_NOT_SPACE: CATEGORY_NOT_SPACE,
    CATEGORY_WORD: CATEGORY_LOC_WORD,
    CATEGORY_NOT_WORD: CATEGORY_LOC_NOT_WORD,
    CATEGORY_LINEBREAK: CATEGORY_LINEBREAK,
    CATEGORY_NOT_LINEBREAK: CATEGORY_NOT_LINEBREAK
}

CH_UNICODE = {
    CATEGORY_DIGIT: CATEGORY_UNI_DIGIT,
    CATEGORY_NOT_DIGIT: CATEGORY_UNI_NOT_DIGIT,
    CATEGORY_SPACE: CATEGORY_UNI_SPACE,
    CATEGORY_NOT_SPACE: CATEGORY_UNI_NOT_SPACE,
    CATEGORY_WORD: CATEGORY_UNI_WORD,
    CATEGORY_NOT_WORD: CATEGORY_UNI_NOT_WORD,
    CATEGORY_LINEBREAK: CATEGORY_UNI_LINEBREAK,
    CATEGORY_NOT_LINEBREAK: CATEGORY_UNI_NOT_LINEBREAK
}

# flags
SRE_FLAG_TEMPLATE = 1 # template mode (disable backtracking)
SRE_FLAG_IGNORECASE = 2 # case insensitive
SRE_FLAG_LOCALE = 4 # honour system locale
SRE_FLAG_MULTILINE = 8 # treat target as multiline string
SRE_FLAG_DOTALL = 16 # treat target as a single string
SRE_FLAG_UNICODE = 32 # use unicode "locale"
SRE_FLAG_VERBOSE = 64 # ignore whitespace and comments
SRE_FLAG_DEBUG = 128 # debugging
SRE_FLAG_ASCII = 256 # use ascii "locale"

# flags for INFO primitive
SRE_INFO_PREFIX = 1 # has prefix
SRE_INFO_LITERAL = 2 # entire pattern is literal (given by prefix)
SRE_INFO_CHARSET = 4 # pattern starts with character from given set

if __name__ == "__main__":
    def dump(f, d, typ, int_t, prefix):
        items = sorted(d)
        f.write(f"""\
#[derive(num_enum::TryFromPrimitive, Debug)]
#[repr({int_t})]
#[allow(non_camel_case_types, clippy::upper_case_acronyms)]
pub enum {typ} {{
""")
        for item in items:
            name = str(item).removeprefix(prefix)
            val = int(item)
            f.write(f"    {name} = {val},\n")
        f.write("""\
}
""")
    import sys
    if len(sys.argv) > 1:
        constants_file = sys.argv[1]
    else:
        import os
        constants_file = os.path.join(os.path.dirname(__file__), "../../sre-engine/src/constants.rs")
    with open(constants_file, "w") as f:
        f.write("""\
/*
 * Secret Labs' Regular Expression Engine
 *
 * regular expression matching engine
 *
 * NOTE: This file is generated by sre_constants.py.  If you need
 * to change anything in here, edit sre_constants.py and run it.
 *
 * Copyright (c) 1997-2001 by Secret Labs AB.  All rights reserved.
 *
 * See the _sre.c file for information on usage and redistribution.
 */

""")

        f.write("use bitflags::bitflags;\n\n");

        f.write("pub const SRE_MAGIC: usize = %d;\n" % MAGIC)

        dump(f, OPCODES, "SreOpcode", "u32", "")
        dump(f, ATCODES, "SreAtCode", "u32", "AT_")
        dump(f, CHCODES, "SreCatCode", "u32", "CATEGORY_")

        def bitflags(typ, int_t, prefix, flags):
            f.write(f"""\
bitflags! {{
    pub struct {typ}: {int_t} {{
""")
            for name in flags:
                val = globals()[prefix + name]
                f.write(f"        const {name} = {val};\n")
            f.write("""\
    }
}
""")

        bitflags("SreFlag", "u16", "SRE_FLAG_", [
            "TEMPLATE",
            "IGNORECASE",
            "LOCALE",
            "MULTILINE",
            "DOTALL",
            "UNICODE",
            "VERBOSE",
            "DEBUG",
            "ASCII",
        ])

        bitflags("SreInfo", "u32", "SRE_INFO_", [
            "PREFIX", "LITERAL", "CHARSET",
        ])

    print("done")