Пример #1
0
 def encode_int12(self, value):
     """encodes 12-bit integer -> 2 char string"""
     if value < 0 or value > 0xFFF:
         raise ValueError("value out of range")
     raw = [value & 0x3f, (value>>6) & 0x3f]
     if self.big:
         raw = reversed(raw)
     return join_byte_elems(imap(self._encode64, raw))
Пример #2
0
 def encode_int12(self, value):
     """encodes 12-bit integer -> 2 char string"""
     if value < 0 or value > 0xFFF:
         raise ValueError("value out of range")
     raw = [value & 0x3f, (value >> 6) & 0x3f]
     if self.big:
         raw = reversed(raw)
     return join_byte_elems(imap(self._encode64, raw))
Пример #3
0
    def encode_bytes(self, source):
        """encode bytes to base64 string.

        :arg source: byte string to encode.
        :returns: byte string containing encoded data.
        """
        if not isinstance(source, bytes):
            raise TypeError("source must be bytes, not %s" % (type(source),))
        chunks, tail = divmod(len(source), 3)
        if PY3:
            next_value = nextgetter(iter(source))
        else:
            next_value = nextgetter(ord(elem) for elem in source)
        gen = self._encode_bytes(next_value, chunks, tail)
        out = join_byte_elems(imap(self._encode64, gen))
        ##if tail:
        ##    padding = self.padding
        ##    if padding:
        ##        out += padding * (3-tail)
        return out
Пример #4
0
    def encode_bytes(self, source):
        """encode bytes to base64 string.

        :arg source: byte string to encode.
        :returns: byte string containing encoded data.
        """
        if not isinstance(source, bytes):
            raise TypeError("source must be bytes, not %s" % (type(source), ))
        chunks, tail = divmod(len(source), 3)
        if PY3:
            next_value = nextgetter(iter(source))
        else:
            next_value = nextgetter(ord(elem) for elem in source)
        gen = self._encode_bytes(next_value, chunks, tail)
        out = join_byte_elems(imap(self._encode64, gen))
        # if tail:
        ##    padding = self.padding
        # if padding:
        ##        out += padding * (3-tail)
        return out
Пример #5
0
    def _encode_int(self, value, bits):
        """encode integer into base64 format

        :arg value: non-negative integer to encode
        :arg bits: number of bits to encode

        :returns:
            a string of length ``int(ceil(bits/6.0))``.
        """
        assert value >= 0, "caller did not sanitize input"
        pad = -bits % 6
        bits += pad
        if self.big:
            itr = irange(bits-6, -6, -6)
            # shift to add lsb padding.
            value <<= pad
        else:
            itr = irange(0, bits, 6)
            # padding is msb, so no change needed.
        return join_byte_elems(imap(self._encode64,
                                ((value>>off) & 0x3f for off in itr)))
Пример #6
0
    def decode_bytes(self, source):
        """decode bytes from base64 string.

        :arg source: byte string to decode.
        :returns: byte string containing decoded data.
        """
        if not isinstance(source, bytes):
            raise TypeError("source must be bytes, not %s" % (type(source),))
        ##padding = self.padding
        ##if padding:
        ##    # TODO: add padding size check?
        ##    source = source.rstrip(padding)
        chunks, tail = divmod(len(source), 4)
        if tail == 1:
            # only 6 bits left, can't encode a whole byte!
            raise ValueError("input string length cannot be == 1 mod 4")
        next_value = nextgetter(imap(self._decode64, source))
        try:
            return join_byte_values(self._decode_bytes(next_value, chunks, tail))
        except KeyError as err:
            raise ValueError("invalid character: %r" % (err.args[0],))
Пример #7
0
    def _encode_int(self, value, bits):
        """encode integer into base64 format

        :arg value: non-negative integer to encode
        :arg bits: number of bits to encode

        :returns:
            a string of length ``int(ceil(bits/6.0))``.
        """
        assert value >= 0, "caller did not sanitize input"
        pad = -bits % 6
        bits += pad
        if self.big:
            itr = irange(bits - 6, -6, -6)
            # shift to add lsb padding.
            value <<= pad
        else:
            itr = irange(0, bits, 6)
            # padding is msb, so no change needed.
        return join_byte_elems(
            imap(self._encode64, ((value >> off) & 0x3f for off in itr)))
Пример #8
0
    def decode_bytes(self, source):
        """decode bytes from base64 string.

        :arg source: byte string to decode.
        :returns: byte string containing decoded data.
        """
        if not isinstance(source, bytes):
            raise TypeError("source must be bytes, not %s" % (type(source),))
        ##padding = self.padding
        ##if padding:
        ##    # TODO: add padding size check?
        ##    source = source.rstrip(padding)
        chunks, tail = divmod(len(source), 4)
        if tail == 1:
            # only 6 bits left, can't encode a whole byte!
            raise ValueError("input string length cannot be == 1 mod 4")
        next_value = nextgetter(imap(self._decode64, source))
        try:
            return join_byte_values(self._decode_bytes(next_value, chunks, tail))
        except KeyError as err:
            raise ValueError("invalid character: %r" % (err.args[0],))