Class GNUTranslations

Lib/gettext.py:334–485

class GNUTranslations(NullTranslations):
    # Magic number of .mo files
    LE_MAGIC = 0x950412de
    BE_MAGIC = 0xde120495

    # The encoding of a msgctxt and a msgid in a .mo file is
    # msgctxt + "\x04" + msgid (gettext version >= 0.15)
    CONTEXT = "%s\x04%s"

    # Acceptable .mo versions
    VERSIONS = (0, 1)

    def _get_versions(self, version):
        """Returns a tuple of major version, minor version"""
        return (version >> 16, version & 0xffff)

    def _parse(self, fp):
        """Override this method to support alternative .mo formats."""
        # Delay struct import for speeding up gettext import when .mo files
        # are not used.
        from struct import unpack
        filename = getattr(fp, 'name', '')
        # Parse the .mo file header, which consists of 5 little endian 32
        # bit words.
        self._catalog = catalog = {}
        self.plural = lambda n: int(n != 1) # germanic plural by default
        buf = fp.read()
        buflen = len(buf)
        # Are we big endian or little endian?
        magic = unpack('<I', buf[:4])[0]
        if magic == self.LE_MAGIC:
            version, msgcount, masteridx, transidx = unpack('<4I', buf[4:20])
            ii = '<II'
        elif magic == self.BE_MAGIC:
            version, msgcount, masteridx, transidx = unpack('>4I', buf[4:20])
            ii = '>II'
        else:
            raise OSError(0, 'Bad magic number', filename)

        major_version, minor_version = self._get_versions(version)

        if major_version not in self.VERSIONS:
            raise OSError(0, 'Bad version number ' + str(major_version), filename)

        # Now put all messages from the .mo file buffer into the catalog
        # dictionary.
        for i in range(0, msgcount):
            mlen, moff = unpack(ii, buf[masteridx:masteridx+8])
            mend = moff + mlen
            tlen, toff = unpack(ii, buf[transidx:transidx+8])
            tend = toff + tlen
            if mend < buflen and tend < buflen:
                msg = buf[moff:mend]
                tmsg = buf[toff:tend]
            else:
                raise OSError(0, 'File is corrupt', filename)
            # See if we're looking at GNU .mo conventions for metadata
            if mlen == 0: