Enter 2006 September/Enter 09 2006.iso/Internet/SpamExperts Home 1.1/SpamExperts Home.exe/lib/spamexperts.modules/dns/tokenizer.pyc

Python Compiled Bytecode | 2006-07-14 | 11.5 KB | 430 lines

# Source Generated with Decompyle++
# File: in.pyc (Python 2.4)

'''Tokenize DNS master file format'''
import cStringIO
import sys
import dns.exception as dns
import dns.name as dns
_DELIMITERS = {
    ' ': True,
    '\t': True,
    '\n': True,
    ';': True,
    '(': True,
    ')': True,
    '"': True }
_QUOTING_DELIMITERS = {
    '"': True }
EOF = 0
EOL = 1
WHITESPACE = 2
IDENTIFIER = 3
QUOTED_STRING = 4
COMMENT = 5
DELIMITER = 6

class UngetBufferFull(dns.exception.DNSException):
    '''Raised when an attempt is made to unget a token when the unget
    buffer is full.'''
    pass


class Tokenizer(object):
    """A DNS master file format tokenizer.

    A token is a (type, value) tuple, where I{type} is an int, and
    I{value} is a string.  The valid types are EOF, EOL, WHITESPACE,
    IDENTIFIER, QUOTED_STRING, COMMENT, and DELIMITER.

    @ivar file: The file to tokenize
    @type file: file
    @ivar ungotten_char: The most recently ungotten character, or None.
    @type ungotten_char: string
    @ivar ungotten_token: The most recently ungotten token, or None.
    @type ungotten_token: (int, string) token tuple
    @ivar multiline: The current multiline level.  This value is increased
    by one every time a '(' delimiter is read, and decreased by one every time
    a ')' delimiter is read.
    @type multiline: int
    @ivar quoting: This variable is true if the tokenizer is currently
    reading a quoted string.
    @type quoting: bool
    @ivar eof: This variable is true if the tokenizer has encountered EOF.
    @type eof: bool
    @ivar delimiters: The current delimiter dictionary.
    @type delimiters: dict
    @ivar line_number: The current line number
    @type line_number: int
    @ivar filename: A filename that will be returned by the L{where} method.
    @type filename: string
    """

    def __init__(self, f = sys.stdin, filename = None):
        '''Initialize a tokenizer instance.

        @param f: The file to tokenize.  The default is sys.stdin.
        This parameter may also be a string, in which case the tokenizer
        will take its input from the contents of the string.
        @type f: file or string
        @param filename: the name of the filename that the L{where} method
        will return.
        @type filename: string
        '''
        if isinstance(f, str):
            f = cStringIO.StringIO(f)
            if filename is None:
                filename = '<string>'

        elif filename is None:
            if f is sys.stdin:
                filename = '<stdin>'
            else:
                filename = '<file>'

        self.file = f
        self.ungotten_char = None
        self.ungotten_token = None
        self.multiline = 0
        self.quoting = False
        self.eof = False
        self.delimiters = _DELIMITERS
        self.line_number = 1
        self.filename = filename


    def _get_char(self):
        '''Read a character from input.
        @rtype: string
        '''
        if self.ungotten_char is None:
            if self.eof:
                c = ''
            else:
                c = self.file.read(1)
                if c == '':
                    self.eof = True
                elif c == '\n':
                    self.line_number += 1

        else:
            c = self.ungotten_char
            self.ungotten_char = None
        return c


    def where(self):
        '''Return the current location in the input.

        @rtype: (string, int) tuple.  The first item is the filename of
        the input, the second is the current line number.
        '''
        return (self.filename, self.line_number)


    def _unget_char(self, c):
        '''Unget a character.

        The unget buffer for characters is only one character large; it is
        an error to try to unget a character when the unget buffer is not
        empty.

        @param c: the character to unget
        @type c: string
        @raises UngetBufferFull: there is already an ungotten char
        '''
        if self.ungotten_char is not None:
            raise UngetBufferFull

        self.ungotten_char = c


    def skip_whitespace(self):
        '''Consume input until a non-whitespace character is encountered.

        The non-whitespace character is then ungotten, and the number of
        whitespace characters consumed is returned.

        If the tokenizer is in multiline mode, then newlines are whitespace.

        @rtype: int
        '''
        skipped = 0
        while True:
            c = self._get_char()
            if c != ' ' and c != '\t':
                if c != '\n' or not (self.multiline):
                    self._unget_char(c)
                    return skipped


            skipped += 1


    def get(self, want_leading = False, want_comment = False):
        '''Get the next token.

        @param want_leading: If True, return a WHITESPACE token if the
        first character read is whitespace.  The default is False.
        @type want_leading: bool
        @param want_comment: If True, return a COMMENT token if the
        first token read is a comment.  The default is False.
        @type want_comment: bool
        @rtype: (int, string) tuple
        @raises dns.exception.UnexpectedEnd: input ended prematurely
        @raises dns.exception.SyntaxError: input was badly formed
        '''
        if self.ungotten_token is not None:
            token = self.ungotten_token
            self.ungotten_token = None
            if token[0] == WHITESPACE:
                if want_leading:
                    return token

            elif token[0] == COMMENT:
                if want_comment:
                    return token

            else:
                return token

        skipped = self.skip_whitespace()
        if want_leading and skipped > 0:
            return (WHITESPACE, ' ')

        token = ''
        ttype = IDENTIFIER
        while True:
            c = self._get_char()
            if c == '' or c in self.delimiters:
                if c == '' and self.quoting:
                    raise dns.exception.UnexpectedEnd

                if token == '' and ttype != QUOTED_STRING:
                    if c == '(':
                        self.multiline += 1
                        self.skip_whitespace()
                        continue
                    elif c == ')':
                        if not self.multiline > 0:
                            raise dns.exception.SyntaxError

                        self.multiline -= 1
                        self.skip_whitespace()
                        continue
                    elif c == '"':
                        if not self.quoting:
                            self.quoting = True
                            self.delimiters = _QUOTING_DELIMITERS
                            ttype = QUOTED_STRING
                            continue
                        else:
                            self.quoting = False
                            self.delimiters = _DELIMITERS
                            self.skip_whitespace()
                    elif c == '\n':
                        return (EOL, '\n')
                    elif c == ';':
                        while None:
                            c = self._get_char()
                            if c == '\n' or c == '':
                                break

                            token += c
                        if want_comment:
                            self._unget_char(c)
                            return (COMMENT, token)
                        elif c == '':
                            if self.multiline:
                                raise dns.exception.SyntaxError, 'unbalanced parentheses'

                            return (EOF, '')
                        elif self.multiline:
                            self.skip_whitespace()
                            token = ''
                            continue
                        else:
                            return (EOL, '\n')
                    else:
                        token = c
                        ttype = DELIMITER
                else:
                    self._unget_char(c)
                break
            elif self.quoting:
                if c == '\\':
                    c = self._get_char()
                    if c == '':
                        raise dns.exception.UnexpectedEnd

                    if c.isdigit():
                        c2 = self._get_char()
                        if c2 == '':
                            raise dns.exception.UnexpectedEnd

                        c3 = self._get_char()
                        if c == '':
                            raise dns.exception.UnexpectedEnd

                        if not c2.isdigit() and c3.isdigit():
                            raise dns.exception.SyntaxError

                        c = chr(int(c) * 100 + int(c2) * 10 + int(c3))

                elif c == '\n':
                    raise dns.exception.SyntaxError, 'newline in quoted string'

            elif c == '\\':
                c = self._get_char()
                if c == '' or c not in self.delimiters:
                    self._unget_char(c)
                    c = '\\'


            token += c
        if token == '' and ttype != QUOTED_STRING:
            if self.multiline:
                raise dns.exception.SyntaxError, 'unbalanced parentheses'

            ttype = EOF

        return (ttype, token)


    def unget(self, token):
        '''Unget a token.

        The unget buffer for tokens is only one token large; it is
        an error to try to unget a token when the unget buffer is not
        empty.

        @param token: the token to unget
        @type token: (int, string) token tuple
        @raises UngetBufferFull: there is already an ungotten token
        '''
        if self.ungotten_token is not None:
            raise UngetBufferFull

        self.ungotten_token = token


    def next(self):
        '''Return the next item in an iteration.
        @rtype: (int, string)
        '''
        token = self.get()
        if token[0] == EOF:
            raise StopIteration

        return token


    def __iter__(self):
        return self


    def get_int(self):
        '''Read the next token and interpret it as an integer.

        @raises dns.exception.SyntaxError:
        @rtype: int
        '''
        (ttype, value) = self.get()
        if ttype != IDENTIFIER:
            raise dns.exception.SyntaxError, 'expecting an identifier'

        if not value.isdigit():
            raise dns.exception.SyntaxError, 'expecting an integer'

        return int(value)


    def get_uint8(self):
        '''Read the next token and interpret it as an 8-bit unsigned
        integer.

        @raises dns.exception.SyntaxError:
        @rtype: int
        '''
        value = self.get_int()
        if value < 0 or value > 255:
            raise dns.exception.SyntaxError, '%d is not an unsigned 8-bit integer' % value

        return value


    def get_uint16(self):
        '''Read the next token and interpret it as a 16-bit unsigned
        integer.

        @raises dns.exception.SyntaxError:
        @rtype: int
        '''
        value = self.get_int()
        if value < 0 or value > 65535:
            raise dns.exception.SyntaxError, '%d is not an unsigned 16-bit integer' % value

        return value


    def get_uint32(self):
        '''Read the next token and interpret it as a 32-bit unsigned
        integer.

        @raises dns.exception.SyntaxError:
        @rtype: int
        '''
        (ttype, value) = self.get()
        if ttype != IDENTIFIER:
            raise dns.exception.SyntaxError, 'expecting an identifier'

        if not value.isdigit():
            raise dns.exception.SyntaxError, 'expecting an integer'

        value = long(value)
        if value < 0 or value > 0x100000000L:
            raise dns.exception.SyntaxError, '%d is not an unsigned 32-bit integer' % value

        return value


    def get_string(self, origin = None):
        '''Read the next token and interpret it as a string.

        @raises dns.exception.SyntaxError:
        @rtype: string
        '''
        (ttype, t) = self.get()
        if ttype != IDENTIFIER and ttype != QUOTED_STRING:
            raise dns.exception.SyntaxError, 'expecting a string'

        return t


    def get_name(self, origin = None):
        '''Read the next token and interpret it as a DNS name.

        @raises dns.exception.SyntaxError:
        @rtype: dns.name.Name object'''
        (ttype, t) = self.get()
        if ttype != IDENTIFIER:
            raise dns.exception.SyntaxError, 'expecting an identifier'

        return dns.name.from_text(t, origin)


    def get_eol(self):
        """Read the next token and raise an exception if it isn't EOL or
        EOF.

        @raises dns.exception.SyntaxError:
        @rtype: string
        """
        (ttype, t) = self.get()
        if ttype != EOL and ttype != EOF:
            raise dns.exception.SyntaxError, 'expected EOL or EOF, got %d "%s"' % (ttype, t)

        return t