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# Source code for astropy.io.votable.exceptions

    # Licensed under a 3-clause BSD style license - see LICENSE.rst
    # -*- coding: utf-8 -*-
    """
    .. _warnings:

    Warnings
    --------

    .. note::
        Most of the following warnings indicate violations of the VOTable
        specification.  They should be reported to the authors of the
        tools that produced the VOTable file.

        To control the warnings emitted, use the standard Python
        :mod:`warnings` module.  Most of these are of the type
        `VOTableSpecWarning`.

    {warnings}

    .. _exceptions:

    Exceptions
    ----------

    .. note::

        This is a list of many of the fatal exceptions emitted by vo.table
        when the file does not conform to spec.  Other exceptions may be
        raised due to unforeseen cases or bugs in vo.table itself.

    {exceptions}
    """

    from __future__ import (absolute_import, division, print_function,
                            unicode_literals)

    from ...extern import six

    # STDLIB
    import io
    import re

    from textwrap import dedent
    from warnings import warn

    from ...utils.exceptions import AstropyWarning

    __all__ = [
        'warn_or_raise', 'vo_raise', 'vo_reraise', 'vo_warn',
        'warn_unknown_attrs', 'parse_vowarning', 'VOWarning',
        'VOTableChangeWarning', 'VOTableSpecWarning',
        'UnimplementedWarning', 'IOWarning', 'VOTableSpecError']

    MAX_WARNINGS = 10

    def _format_message(message, name, config={}, pos=None):
        if pos is None:
            pos = ('?', '?')
        filename = config.get('filename', '?')
        return '%s:%s:%s: %s: %s' % (filename, pos[0], pos[1], name, message)

    def _suppressed_warning(warning, config, stacklevel=2):
        warning_class = type(warning)
        config.setdefault('_warning_counts', {}).setdefault(warning_class, 0)
        config['_warning_counts'][warning_class] += 1
        message_count = config['_warning_counts'][warning_class]
        if message_count <= MAX_WARNINGS:
            if message_count == MAX_WARNINGS:
                warning.formatted_message += \
                    ' (suppressing further warnings of this type...)'
            warn(warning, stacklevel=stacklevel+1)

    def warn_or_raise(warning_class, exception_class=None, args=(), config={},
                      pos=None, stacklevel=1):
        """
        Warn or raise an exception, depending on the pedantic setting.
        """
        if config.get('pedantic'):
            if exception_class is None:
                exception_class = warning_class
            vo_raise(exception_class, args, config, pos)
        else:
            vo_warn(warning_class, args, config, pos, stacklevel=stacklevel+1)

    def vo_raise(exception_class, args=(), config={}, pos=None):
        """
        Raise an exception, with proper position information if available.
        """
        raise exception_class(args, config, pos)

    def vo_reraise(exc, config={}, pos=None, additional=''):
        """
        Raise an exception, with proper position information if available.

        Restores the original traceback of the exception, and should only
        be called within an "except:" block of code.
        """
        message = _format_message(str(exc), exc.__class__.__name__, config, pos)
        if message.split()[0] == str(exc).split()[0]:
            message = str(exc)
        if len(additional):
            message += ' ' + additional
        exc.args = (message,)
        raise exc

    def vo_warn(warning_class, args=(), config={}, pos=None, stacklevel=1):
        """
        Warn, with proper position information if available.
        """
        warning = warning_class(args, config, pos)
        _suppressed_warning(warning, config, stacklevel=stacklevel+1)

    def warn_unknown_attrs(element, attrs, config, pos, good_attr=[], stacklevel=1):
        for attr in attrs:
            if attr not in good_attr:
                vo_warn(W48, (attr, element), config, pos, stacklevel=stacklevel+1)

    _warning_pat = re.compile(
        (r":?(?P<nline>[0-9?]+):(?P<nchar>[0-9?]+): " +
         r"((?P<warning>[WE]\d+): )?(?P<rest>.*)$"))

    def parse_vowarning(line):
        """
        Parses the vo warning string back into its parts.
        """
        result = {}
        match = _warning_pat.search(line)
        if match:
            result['warning'] = warning = match.group('warning')
            if warning is not None:
                result['is_warning'] = (warning[0].upper() == 'W')
                result['is_exception'] = not result['is_warning']
                result['number'] = int(match.group('warning')[1:])
                result['doc_url'] = "io/votable/api_exceptions.html#{0}".format(
                    warning.lower())
            else:
                result['is_warning'] = False
                result['is_exception'] = False
                result['is_other'] = True
                result['number'] = None
                result['doc_url'] = None
            try:
                result['nline'] = int(match.group('nline'))
            except ValueError:
                result['nline'] = 0
            try:
                result['nchar'] = int(match.group('nchar'))
            except ValueError:
                result['nchar'] = 0
            result['message'] = match.group('rest')
            result['is_something'] = True
        else:
            result['warning'] = None
            result['is_warning'] = False
            result['is_exception'] = False
            result['is_other'] = False
            result['is_something'] = False
            if not isinstance(line, six.text_type):
                line = line.decode('utf-8')
            result['message'] = line

        return result

    class VOWarning(AstropyWarning):
        """
        The base class of all VO warnings and exceptions.

        Handles the formatting of the message with a warning or exception
        code, filename, line and column number.
        """
        default_args = ()

        def __init__(self, args, config={}, pos=None):
            msg = self.message % args
            self.formatted_message = _format_message(
                msg, self.__class__.__name__, config, pos)
            Warning.__init__(self, self.formatted_message)

        def __str__(self):
            return self.formatted_message

        @classmethod
        def get_short_name(cls):
            if len(cls.default_args):
                return cls.message % cls.default_args
            return cls.message

    class VOTableChangeWarning(VOWarning, SyntaxWarning):
        """
        A change has been made to the input XML file.
        """
        pass

    class VOTableSpecWarning(VOWarning, SyntaxWarning):
        """
        The input XML file violates the spec, but there is an obvious workaround.
        """
        pass

    class UnimplementedWarning(VOWarning, SyntaxWarning):
        """
        A feature of the VOTABLE_ spec is not implemented.
        """
        pass

    class IOWarning(VOWarning, RuntimeWarning):
        """
        A network or IO error occurred, but was recovered using the cache.
        """
        pass

    class VOTableSpecError(VOWarning, ValueError):
        """
        The input XML file violates the spec and there is no good workaround.
        """
        pass

    class W01(VOTableSpecWarning):
        """
        The VOTable spec states:

            If a cell contains an array or complex number, it should be
            encoded as multiple numbers separated by whitespace.

        Many VOTable files in the wild use commas as a separator instead,
        and ``vo.table`` supports this convention when not in
        :ref:`pedantic-mode`.

        `vo.table` always outputs files using only spaces, regardless of
        how they were input.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#toc-header-35>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:TABLEDATA>`__
        """

        message = "Array uses commas rather than whitespace"

    class W02(VOTableSpecWarning):
        """
        XML ids must match the following regular expression::

            ^[A-Za-z_][A-Za-z0-9_\.\-]*$

        The VOTable 1.1 says the following:

            According to the XML standard, the attribute ``ID`` is a
            string beginning with a letter or underscore (``_``), followed
            by a sequence of letters, digits, or any of the punctuation
            characters ``.`` (dot), ``-`` (dash), ``_`` (underscore), or
            ``:`` (colon).

        However, this is in conflict with the XML standard, which says
        colons may not be used.  VOTable 1.1's own schema does not allow a
        colon here.  Therefore, ``vo.table`` disallows the colon.

        VOTable 1.2 corrects this error in the specification.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `XML Names <http://www.w3.org/TR/REC-xml/#NT-Name>`__
        """

        message = "%s attribute '%s' is invalid.  Must be a standard XML id"
        default_args = ('x', 'y')

    class W03(VOTableChangeWarning):
        """
        The VOTable 1.1 spec says the following about ``name`` vs. ``ID``
        on ``FIELD`` and ``VALUE`` elements:

            ``ID`` and ``name`` attributes have a different role in
            VOTable: the ``ID`` is meant as a *unique identifier* of an
            element seen as a VOTable component, while the ``name`` is
            meant for presentation purposes, and need not to be unique
            throughout the VOTable document. The ``ID`` attribute is
            therefore required in the elements which have to be
            referenced, but in principle any element may have an ``ID``
            attribute. ... In summary, the ``ID`` is different from the
            ``name`` attribute in that (a) the ``ID`` attribute is made
            from a restricted character set, and must be unique throughout
            a VOTable document whereas names are standard XML attributes
            and need not be unique; and (b) there should be support in the
            parsing software to look up references and extract the
            relevant element with matching ``ID``.

        It is further recommended in the VOTable 1.2 spec:

            While the ``ID`` attribute has to be unique in a VOTable
            document, the ``name`` attribute need not. It is however
            recommended, as a good practice, to assign unique names within
            a ``TABLE`` element. This recommendation means that, between a
            ``TABLE`` and its corresponding closing ``TABLE`` tag,
            ``name`` attributes of ``FIELD``, ``PARAM`` and optional
            ``GROUP`` elements should be all different.

        Since ``vo.table`` requires a unique identifier for each of its
        columns, ``ID`` is used for the column name when present.
        However, when ``ID`` is not present, (since it is not required by
        the specification) ``name`` is used instead.  However, ``name``
        must be cleansed by replacing invalid characters (such as
        whitespace) with underscores.

        .. note::
            This warning does not indicate that the input file is invalid
            with respect to the VOTable specification, only that the
            column names in the record array may not match exactly the
            ``name`` attributes specified in the file.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = "Implictly generating an ID from a name '%s' -> '%s'"
        default_args = ('x', 'y')

    class W04(VOTableSpecWarning):
        """
        The ``content-type`` attribute must use MIME content-type syntax as
        defined in `RFC 2046 <http://tools.ietf.org/html/rfc2046>`__.

        The current check for validity is somewhat over-permissive.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:link>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:link>`__
        """

        message = "content-type '%s' must be a valid MIME content type"
        default_args = ('x',)

    class W05(VOTableSpecWarning):
        """
        The attribute must be a valid URI as defined in `RFC 2396
        <http://www.ietf.org/rfc/rfc2396.txt>`_.
        """

        message = "'%s' is not a valid URI"
        default_args = ('x',)

    class W06(VOTableSpecWarning):
        """
        This warning is emitted when a ``ucd`` attribute does not match
        the syntax of a `unified content descriptor
        <http://vizier.u-strasbg.fr/doc/UCD.htx>`__.

        If the VOTable version is 1.2 or later, the UCD will also be
        checked to ensure it conforms to the controlled vocabulary defined
        by UCD1+.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:ucd>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:ucd>`__
        """

        message = "Invalid UCD '%s': %s"
        default_args = ('x', 'explanation')

    class W07(VOTableSpecWarning):
        """
        As astro year field is a Besselian or Julian year matching the
        regular expression::

            ^[JB]?[0-9]+([.][0-9]*)?$

        Defined in this XML Schema snippet::

            <xs:simpleType  name="astroYear">
              <xs:restriction base="xs:token">
                <xs:pattern  value="[JB]?[0-9]+([.][0-9]*)?"/>
              </xs:restriction>
            </xs:simpleType>
        """

        message = "Invalid astroYear in %s: '%s'"
        default_args = ('x', 'y')

    class W08(VOTableSpecWarning):
        """
        To avoid local-dependent number parsing differences, ``vo.table``
        may require a string or unicode string where a numeric type may
        make more sense.
        """

        if six.PY3:
            message = "'%s' must be a str or bytes object"
        else:
            message = "'%s' must be a str or unicode object"
        default_args = ('x',)

    class W09(VOTableSpecWarning):
        """
        The VOTable specification uses the attribute name ``ID`` (with
        uppercase letters) to specify unique identifiers.  Some
        VOTable-producing tools use the more standard lowercase ``id``
        instead.  ``vo.table`` accepts ``id`` and emits this warning when
        not in ``pedantic`` mode.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = "ID attribute not capitalized"

    class W10(VOTableSpecWarning):
        """
        The parser has encountered an element that does not exist in the
        specification, or appears in an invalid context.  Check the file
        against the VOTable schema (with a tool such as `xmllint
        <http://xmlsoft.org/xmllint.html>`__.  If the file validates
        against the schema, and you still receive this warning, this may
        indicate a bug in ``vo.table``.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__
        """

        message = "Unknown tag '%s'.  Ignoring"
        default_args = ('x',)

    class W11(VOTableSpecWarning):
        """
        Earlier versions of the VOTable specification used a ``gref``
        attribute on the ``LINK`` element to specify a `GLU reference
        <http://aladin.u-strasbg.fr/glu/>`__.  New files should
        specify a ``glu:`` protocol using the ``href`` attribute.

        Since ``vo.table`` does not currently support GLU references, it
        likewise does not automatically convert the ``gref`` attribute to
        the new form.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:link>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:link>`__
        """

        message = "The gref attribute on LINK is deprecated in VOTable 1.1"

    class W12(VOTableChangeWarning):
        """
        In order to name the columns of the Numpy record array, each
        ``FIELD`` element must have either an ``ID`` or ``name`` attribute
        to derive a name from.  Strictly speaking, according to the
        VOTable schema, the ``name`` attribute is required.  However, if
        ``name`` is not present by ``ID`` is, and *pedantic mode* is off,
        ``vo.table`` will continue without a ``name`` defined.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = (
            "'%s' element must have at least one of 'ID' or 'name' attributes")
        default_args = ('x',)

    class W13(VOTableSpecWarning):
        """
        Some VOTable files in the wild use non-standard datatype names.  These
        are mapped to standard ones using the following mapping::

           string        -> char
           unicodeString -> unicodeChar
           int16         -> short
           int32         -> int
           int64         -> long
           float32       -> float
           float64       -> double

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "'%s' is not a valid VOTable datatype, should be '%s'"
        default_args = ('x', 'y')

    # W14: Deprecated

    class W15(VOTableSpecWarning):
        """
        The ``name`` attribute is required on every ``FIELD`` element.
        However, many VOTable files in the wild omit it and provide only
        an ``ID`` instead.  In this case, when *pedantic mode* is off,
        ``vo.table`` will copy the ``name`` attribute to a new ``ID``
        attribute.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = "%s element missing required 'name' attribute"
        default_args = ('x',)

    # W16: Deprecated

    class W17(VOTableSpecWarning):
        """
        A ``DESCRIPTION`` element can only appear once within its parent
        element.

        According to the schema, it may only occur once (`1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__)

        However, it is a `proposed extension
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:addesc>`__
        to VOTable 1.2.
        """

        message = "%s element contains more than one DESCRIPTION element"
        default_args = ('x',)

    class W18(VOTableSpecWarning):
        """
        The number of rows explicitly specified in the ``nrows`` attribute
        does not match the actual number of rows (``TR`` elements) present
        in the ``TABLE``.  This may indicate truncation of the file, or an
        internal error in the tool that produced it.  If *pedantic mode*
        is off, parsing will proceed, with the loss of some performance.

        **References:** `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC10>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC10>`__
        """

        message = 'TABLE specified nrows=%s, but table contains %s rows'
        default_args = ('x', 'y')

    class W19(VOTableSpecWarning):
        """
        The column fields as defined using ``FIELD`` elements do not match
        those in the headers of the embedded FITS file.  If *pedantic
        mode* is off, the embedded FITS file will take precedence.
        """

        message = (
            'The fields defined in the VOTable do not match those in the ' +
            'embedded FITS file')

    class W20(VOTableSpecWarning):
        """
        If no version number is explicitly given in the VOTable file, the
        parser assumes it is written to the VOTable 1.1 specification.
        """

        message = 'No version number specified in file.  Assuming %s'
        default_args = ('1.1',)

    class W21(UnimplementedWarning):
        """
        Unknown issues may arise using ``vo.table`` with VOTable files
        from a version other than 1.1, 1.2 or 1.3.
        """

        message = (
            'vo.table is designed for VOTable version 1.1, 1.2 and 1.3, but ' +
            'this file is %s')
        default_args = ('x',)

    class W22(VOTableSpecWarning):
        """
        Version 1.0 of the VOTable specification used the ``DEFINITIONS``
        element to define coordinate systems.  Version 1.1 now uses
        ``COOSYS`` elements throughout the document.

        **References:** `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:definitions>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:definitions>`__
        """

        message = 'The DEFINITIONS element is deprecated in VOTable 1.1.  Ignoring'

    class W23(IOWarning):
        """
        Raised when the VO service database can not be updated (possibly
        due to a network outage).  This is only a warning, since an older
        and possible out-of-date VO service database was available
        locally.
        """

        message = "Unable to update service information for '%s'"
        default_args = ('x',)

    class W24(VOWarning, FutureWarning):
        """
        The VO catalog database retrieved from the www is designed for a
        newer version of vo.table.  This may cause problems or limited
        features performing service queries.  Consider upgrading vo.table
        to the latest version.
        """

        message = "The VO catalog database is for a later version of vo.table"

    class W25(IOWarning):
        """
        A VO service query failed due to a network error or malformed
        arguments.  Another alternative service may be attempted.  If all
        services fail, an exception will be raised.
        """

        message = "'%s' failed with: %s"
        default_args = ('service', '...')

    class W26(VOTableSpecWarning):
        """
        The given element was not supported inside of the given element
        until the specified VOTable version, however the version declared
        in the file is for an earlier version.  These attributes may not
        be written out to the file.
        """

        message = "'%s' inside '%s' added in VOTable %s"
        default_args = ('child', 'parent', 'X.X')

    class W27(VOTableSpecWarning):
        """
        The ``COOSYS`` element was deprecated in VOTABLE version 1.2 in
        favor of a reference to the Space-Time Coordinate (STC) data
        model (see `utype
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:utype>`__
        and the IVOA note `referencing STC in VOTable
        <http://ivoa.net/Documents/latest/VOTableSTC.html>`__.
        """

        message = "COOSYS deprecated in VOTable 1.2"

    class W28(VOTableSpecWarning):
        """
        The given attribute was not supported on the given element until the
        specified VOTable version, however the version declared in the file is
        for an earlier version.  These attributes may not be written out to
        the file.
        """

        message = "'%s' on '%s' added in VOTable %s"
        default_args = ('attribute', 'element', 'X.X')

    class W29(VOTableSpecWarning):
        """
        Some VOTable files specify their version number in the form "v1.0",
        when the only supported forms in the spec are "1.0".

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__
        """

        message = "Version specified in non-standard form '%s'"
        default_args = ('v1.0',)

    class W30(VOTableSpecWarning):
        """
        Some VOTable files write missing floating-point values in non-standard
        ways, such as "null" and "-".  In non-pedantic mode, any non-standard
        floating-point literals are treated as missing values.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "Invalid literal for float '%s'.  Treating as empty."
        default_args = ('x',)

    class W31(VOTableSpecWarning):
        """
        Since NaN's can not be represented in integer fields directly, a null
        value must be specified in the FIELD descriptor to support reading
        NaN's from the tabledata.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "NaN given in an integral field without a specified null value"

    class W32(VOTableSpecWarning):
        """
        Each field in a table must have a unique ID.  If two or more fields
        have the same ID, some will be renamed to ensure that all IDs are
        unique.

        From the VOTable 1.2 spec:

            The ``ID`` and ``ref`` attributes are defined as XML types
            ``ID`` and ``IDREF`` respectively. This means that the
            contents of ``ID`` is an identifier which must be unique
            throughout a VOTable document, and that the contents of the
            ``ref`` attribute represents a reference to an identifier
            which must exist in the VOTable document.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = "Duplicate ID '%s' renamed to '%s' to ensure uniqueness"
        default_args = ('x', 'x_2')

    class W33(VOTableChangeWarning):
        """
        Each field in a table must have a unique name.  If two or more
        fields have the same name, some will be renamed to ensure that all
        names are unique.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:name>`__
        """

        message = "Column name '%s' renamed to '%s' to ensure uniqueness"
        default_args = ('x', 'x_2')

    class W34(VOTableSpecWarning):
        """
        The attribute requires the value to be a valid XML token, as
        defined by `XML 1.0
        <http://www.w3.org/TR/2000/WD-xml-2e-20000814#NT-Nmtoken>`__.
        """

        message = "'%s' is an invalid token for attribute '%s'"
        default_args = ('x', 'y')

    class W35(VOTableSpecWarning):
        """
        The ``name`` and ``value`` attributes are required on all ``INFO``
        elements.

        **References:** `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC32>`
        """

        message = "'%s' attribute required for INFO elements"
        default_args = ('x',)

    class W36(VOTableSpecWarning):
        """
        If the field specifies a ``null`` value, that value must conform
        to the given ``datatype``.

        **References:** `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:values>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:values>`
        """

        message = "null value '%s' does not match field datatype, setting to 0"
        default_args = ('x',)

    class W37(UnimplementedWarning):
        """
        The 3 datatypes defined in the VOTable specification and supported by
        vo.table are ``TABLEDATA``, ``BINARY`` and ``FITS``.

        **References:** `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:data>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:data>`
        """

        message = "Unsupported data format '%s'"
        default_args = ('x',)

    class W38(VOTableSpecWarning):
        """
        The only encoding for local binary data supported by the VOTable
        specification is base64.
        """

        message = "Inline binary data must be base64 encoded, got '%s'"
        default_args = ('x',)

    class W39(VOTableSpecWarning):
        """
        Bit values do not support masking.  This warning is raised upon
        setting masked data in a bit column.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "Bit values can not be masked"

    class W40(VOTableSpecWarning):
        """
        This is a terrible hack to support Simple Image Access Protocol
        results from `archive.noao.edu <http://archive.noao.edu>`__.  It
        creates a field for the coordinate projection type of type "double",
        which actually contains character data.  We have to hack the field
        to store character data, or we can't read it in.  A warning will be
        raised when this happens.
        """

        message = "'cprojection' datatype repaired"

    class W41(VOTableSpecWarning):
        """
        An XML namespace was specified on the ``VOTABLE`` element, but the
        namespace does not match what is expected for a ``VOTABLE`` file.

        The ``VOTABLE`` namespace is::

          http://www.ivoa.net/xml/VOTable/vX.X

        where "X.X" is the version number.

        Some files in the wild set the namespace to the location of the
        VOTable schema, which is not correct and will not pass some
        validating parsers.
        """

        message = (
            "An XML namespace is specified, but is incorrect.  Expected " +
            "'%s', got '%s'")
        default_args = ('x', 'y')

    class W42(VOTableSpecWarning):
        """
        The root element should specify a namespace.

        The ``VOTABLE`` namespace is::

            http://www.ivoa.net/xml/VOTable/vX.X

        where "X.X" is the version number.
        """

        message = "No XML namespace specified"

    class W43(VOTableSpecWarning):
        """
        Referenced elements should be defined before referees.  From the
        VOTable 1.2 spec:

           In VOTable1.2, it is further recommended to place the ID
           attribute prior to referencing it whenever possible.
        """

        message = "%s ref='%s' which has not already been defined"
        default_args = ('element', 'x',)

    class W44(VOTableSpecWarning):
        """
        ``VALUES`` elements that reference another element should not have
        their own content.

        From the VOTable 1.2 spec:

            The ``ref`` attribute of a ``VALUES`` element can be used to
            avoid a repetition of the domain definition, by referring to a
            previously defined ``VALUES`` element having the referenced
            ``ID`` attribute. When specified, the ``ref`` attribute
            defines completely the domain without any other element or
            attribute, as e.g. ``<VALUES ref="RAdomain"/>``
        """

        message = "VALUES element with ref attribute has content ('%s')"
        default_args = ('element',)

    class W45(VOWarning, ValueError):
        """
        The ``content-role`` attribute on the ``LINK`` element must be one of
        the following::

            query, hints, doc, location

        And in VOTable 1.3, additionally::

            type

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__
        `1.3
        <http://www.ivoa.net/documents/VOTable/20130315/PR-VOTable-1.3-20130315.html#sec:link>`__
        """

        message = "content-role attribute '%s' invalid"
        default_args = ('x',)

    class W46(VOTableSpecWarning):
        """
        The given char or unicode string is too long for the specified
        field length.
        """

        message = "%s value is too long for specified length of %s"
        default_args = ('char or unicode', 'x')

    class W47(VOTableSpecWarning):
        """
        If no arraysize is specified on a char field, the default of '1'
        is implied, but this is rarely what is intended.
        """

        message = "Missing arraysize indicates length 1"

    class W48(VOTableSpecWarning):
        """
        The attribute is not defined in the specification.
        """

        message = "Unknown attribute '%s' on %s"
        default_args = ('attribute', 'element')

    class W49(VOTableSpecWarning):
        """
        Prior to VOTable 1.3, the empty cell was illegal for integer
        fields.

        If a \"null\" value was specified for the cell, it will be used
        for the value, otherwise, 0 will be used.
        """

        message = "Empty cell illegal for integer fields."

    class W50(VOTableSpecWarning):
        """
        Invalid unit string as defined in the `Standards for Astronomical
        Catalogues, Version 2.0
        <http://cdsarc.u-strasbg.fr/doc/catstd-3.2.htx>`_.

        Consider passing an explicit `unit_format` parameter if the units
        in this file conform to another specification.
        """

        message = "Invalid unit string '%s'"
        default_args = ('x',)

    class W51(VOTableSpecWarning):
        """
        The integer value is out of range for the size of the field.
        """

        message = "Value '%s' is out of range for a %s integer field"
        default_args = ('x', 'n-bit')

    class W52(VOTableSpecWarning):
        """
        The BINARY2 format was introduced in VOTable 1.3.  It should
        not be present in files marked as an earlier version.
        """

        message = ("The BINARY2 format was introduced in VOTable 1.3, but "
                   "this file is declared as version '%s'")
        default_args = ('1.2',)

    class W53(VOTableSpecWarning):
        """
        The VOTABLE element must contain at least one RESOURCE element.
        """

        message = ("VOTABLE element must contain at least one RESOURCE element.")
        default_args = ()

    class E01(VOWarning, ValueError):
        """
        The size specifier for a ``char`` or ``unicode`` field must be
        only a number followed, optionally, by an asterisk.
        Multi-dimensional size specifiers are not supported for these
        datatypes.

        Strings, which are defined as a set of characters, can be
        represented in VOTable as a fixed- or variable-length array of
        characters::

            <FIELD name="unboundedString" datatype="char" arraysize="*"/>

        A 1D array of strings can be represented as a 2D array of
        characters, but given the logic above, it is possible to define a
        variable-length array of fixed-length strings, but not a
        fixed-length array of variable-length strings.
        """

        message = "Invalid size specifier '%s' for a %s field (in field '%s')"
        default_args = ('x', 'char/unicode', 'y')

    class E02(VOWarning, ValueError):
        """
        The number of array elements in the data does not match that specified
        in the FIELD specifier.
        """

        message = (
            "Incorrect number of elements in array. " +
            "Expected multiple of %s, got %s")
        default_args = ('x', 'y')

    class E03(VOWarning, ValueError):
        """
        Complex numbers should be two values separated by whitespace.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "'%s' does not parse as a complex number"
        default_args = ('x',)

    class E04(VOWarning, ValueError):
        """
        A ``bit`` array should be a string of '0's and '1's.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "Invalid bit value '%s'"
        default_args = ('x',)

    class E05(VOWarning, ValueError):
        """
        A ``boolean`` value should be one of the following strings (case
        insensitive) in the ``TABLEDATA`` format::

            'TRUE', 'FALSE', '1', '0', 'T', 'F', '\\0', ' ', '?'

        and in ``BINARY`` format::

            'T', 'F', '1', '0', '\\0', ' ', '?'

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "Invalid boolean value '%s'"
        default_args = ('x',)

    class E06(VOWarning, ValueError):
        """
        The supported datatypes are::

            double, float, bit, boolean, unsignedByte, short, int, long,
            floatComplex, doubleComplex, char, unicodeChar

        The following non-standard aliases are also supported, but in
        these case :ref:`W13 <W13>` will be raised::

            string        -> char
            unicodeString -> unicodeChar
            int16         -> short
            int32         -> int
            int64         -> long
            float32       -> float
            float64       -> double

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:datatypes>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:datatypes>`__
        """

        message = "Unknown datatype '%s' on field '%s'"
        default_args = ('x', 'y')

    # E07: Deprecated

    class E08(VOWarning, ValueError):
        """
        The ``type`` attribute on the ``VALUES`` element must be either
        ``legal`` or ``actual``.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:values>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:values>`__
        """

        message = "type must be 'legal' or 'actual', but is '%s'"
        default_args = ('x',)

    class E09(VOWarning, ValueError):
        """
        The ``MIN``, ``MAX`` and ``OPTION`` elements must always have a
        ``value`` attribute.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:values>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:values>`__
        """

        message = "'%s' must have a value attribute"
        default_args = ('x',)

    class E10(VOWarning, ValueError):
        """
        From VOTable 1.1 and later, ``FIELD`` and ``PARAM`` elements must have
        a ``datatype`` field.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#elem:FIELD>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#elem:FIELD>`__
        """

        message = "'datatype' attribute required on all '%s' elements"
        default_args = ('FIELD',)

    class E11(VOWarning, ValueError):
        """
        The precision attribute is meant to express the number of significant
        digits, either as a number of decimal places (e.g. ``precision="F2"`` or
        equivalently ``precision="2"`` to express 2 significant figures
        after the decimal point), or as a number of significant figures
        (e.g. ``precision="E5"`` indicates a relative precision of 10-5).

        It is validated using the following regular expression::

            [EF]?[1-9][0-9]*

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:form>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:form>`__
        """

        message = "precision '%s' is invalid"
        default_args = ('x',)

    class E12(VOWarning, ValueError):
        """
        The width attribute is meant to indicate to the application the
        number of characters to be used for input or output of the
        quantity.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:form>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:form>`__
        """

        message = "width must be a positive integer, got '%s'"
        default_args = ('x',)

    class E13(VOWarning, ValueError):
        """
        From the VOTable 1.2 spec:

            A table cell can contain an array of a given primitive type,
            with a fixed or variable number of elements; the array may
            even be multidimensional. For instance, the position of a
            point in a 3D space can be defined by the following::

                <FIELD ID="point_3D" datatype="double" arraysize="3"/>

            and each cell corresponding to that definition must contain
            exactly 3 numbers. An asterisk (\*) may be appended to
            indicate a variable number of elements in the array, as in::

                <FIELD ID="values" datatype="int" arraysize="100*"/>

            where it is specified that each cell corresponding to that
            definition contains 0 to 100 integer numbers. The number may
            be omitted to specify an unbounded array (in practice up to
            =~2×10⁹ elements).

            A table cell can also contain a multidimensional array of a
            given primitive type. This is specified by a sequence of
            dimensions separated by the ``x`` character, with the first
            dimension changing fastest; as in the case of a simple array,
            the last dimension may be variable in length. As an example,
            the following definition declares a table cell which may
            contain a set of up to 10 images, each of 64×64 bytes::

                <FIELD ID="thumbs" datatype="unsignedByte" arraysize="64×64×10*"/>

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:dim>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#sec:dim>`__
        """

        message = "Invalid arraysize attribute '%s'"
        default_args = ('x',)

    class E14(VOWarning, ValueError):
        """
        All ``PARAM`` elements must have a ``value`` attribute.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#elem:FIELD>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#elem:FIELD>`__
        """

        message = "value attribute is required for all PARAM elements"

    class E15(VOWarning, ValueError):
        """
        All ``COOSYS`` elements must have an ``ID`` attribute.

        Note that the VOTable 1.1 specification says this attribute is
        optional, but its corresponding schema indicates it is required.

        In VOTable 1.2, the ``COOSYS`` element is deprecated.
        """

        message = "ID attribute is required for all COOSYS elements"

    class E16(VOTableSpecWarning):
        """
        The ``system`` attribute on the ``COOSYS`` element must be one of the
        following::

          'eq_FK4', 'eq_FK5', 'ICRS', 'ecl_FK4', 'ecl_FK5', 'galactic',
          'supergalactic', 'xy', 'barycentric', 'geo_app'

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#elem:COOSYS>`__
        """

        message = "Invalid system attribute '%s'"
        default_args = ('x',)

    class E17(VOWarning, ValueError):
        """
        ``extnum`` attribute must be a positive integer.

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__
        """

        message = "extnum must be a positive integer"

    class E18(VOWarning, ValueError):
        """
        The ``type`` attribute of the ``RESOURCE`` element must be one of
        "results" or "meta".

        **References**: `1.1
        <http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC54>`__,
        `1.2
        <http://www.ivoa.net/Documents/VOTable/20091130/REC-VOTable-1.2.html#ToC58>`__
        """

        message = "type must be 'results' or 'meta', not '%s'"
        default_args = ('x',)

    class E19(VOWarning, ValueError):
        """
        Raised either when the file doesn't appear to be XML, or the root
        element is not VOTABLE.
        """

        message = "File does not appear to be a VOTABLE"

    class E20(VOTableSpecError):
        """
        The table had only *x* fields defined, but the data itself has more
        columns than that.
        """

        message = "Data has more columns than are defined in the header (%s)"
        default_args = ('x',)

    class E21(VOWarning, ValueError):
        """
        The table had *x* fields defined, but the data itself has only *y*
        columns.
        """

        message = "Data has fewer columns (%s) than are defined in the header (%s)"
        default_args = ('x', 'y')

    def _get_warning_and_exception_classes(prefix):
        classes = []
        for key, val in six.iteritems(globals()):
            if re.match(prefix + "[0-9]{2}", key):
                classes.append((key, val))
        classes.sort()
        return classes

    def _build_doc_string():
        def generate_set(prefix):
            classes = _get_warning_and_exception_classes(prefix)

            out = io.StringIO()

            for name, cls in classes:
                out.write(".. _%s:\n\n" % name)
                msg = "%s: %s" % (cls.__name__, cls.get_short_name())
                if not isinstance(msg, six.text_type):
                    msg = msg.decode('utf-8')
                out.write(msg)
                out.write('\n')
                out.write('~' * len(msg))
                out.write('\n\n')
                doc = cls.__doc__
                if not isinstance(doc, six.text_type):
                    doc = doc.decode('utf-8')
                out.write(dedent(doc))
                out.write('\n\n')

            return out.getvalue()

        warnings = generate_set('W')
        exceptions = generate_set('E')

        return {'warnings': warnings,
                'exceptions': exceptions}

    __doc__ = __doc__.format(**_build_doc_string())

    __all__.extend([x[0] for x in _get_warning_and_exception_classes('W')])
    __all__.extend([x[0] for x in _get_warning_and_exception_classes('E')])