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# Source code for astropy.io.ascii.fixedwidth

    # Licensed under a 3-clause BSD style license - see LICENSE.rst
    """An extensible ASCII table reader and writer.

    fixedwidth.py:
      Read or write a table with fixed width columns.

    :Copyright: Smithsonian Astrophysical Observatory (2011)
    :Author: Tom Aldcroft (aldcroft@head.cfa.harvard.edu)
    """

    from __future__ import absolute_import, division, print_function

    from ...extern.six.moves import zip

    from . import core
    from .core import InconsistentTableError, DefaultSplitter
    from . import basic

    class FixedWidthSplitter(core.BaseSplitter):
        """
        Split line based on fixed start and end positions for each ``col`` in
        ``self.cols``.

        This class requires that the Header class will have defined ``col.start``
        and ``col.end`` for each column.  The reference to the ``header.cols`` gets
        put in the splitter object by the base Reader.read() function just in time
        for splitting data lines by a ``data`` object.

        Note that the ``start`` and ``end`` positions are defined in the pythonic
        style so line[start:end] is the desired substring for a column.  This splitter
        class does not have a hook for ``process_lines`` since that is generally not
        useful for fixed-width input.

        """
        delimiter_pad = ''
        bookend = False
        delimiter = '|'

        def __call__(self, lines):
            for line in lines:
                vals = [line[x.start:x.end] for x in self.cols]
                if self.process_val:
                    yield [self.process_val(x) for x in vals]
                else:
                    yield vals

        def join(self, vals, widths):
            pad = self.delimiter_pad or ''
            delimiter = self.delimiter or ''
            padded_delim = pad + delimiter + pad
            if self.bookend:
                bookend_left = delimiter + pad
                bookend_right = pad + delimiter
            else:
                bookend_left = ''
                bookend_right = ''
            vals = [' ' * (width - len(val)) + val for val, width in zip(vals, widths)]
            return bookend_left + padded_delim.join(vals) + bookend_right

    class FixedWidthHeaderSplitter(DefaultSplitter):
        '''Splitter class that splits on ``|``.'''
        delimiter = '|'

    class FixedWidthHeader(basic.BasicHeader):
        """
        Fixed width table header reader.
        """
        splitter_class = FixedWidthHeaderSplitter
        """ Splitter class for splitting data lines into columns """
        position_line = None   # secondary header line position
        """ row index of line that specifies position (default = 1) """
        set_of_position_line_characters = set(r'`~!#$%^&*-_+=\|":' + "'")

        def get_line(self, lines, index):
            for i, line in enumerate(self.process_lines(lines)):
                if i == index:
                    break
            else:  # No header line matching
                raise InconsistentTableError('No header line found in table')
            return line

        def get_cols(self, lines):
            """
            Initialize the header Column objects from the table ``lines``.

            Based on the previously set Header attributes find or create the column names.
            Sets ``self.cols`` with the list of Columns.

            Parameters
            ----------
            lines : list
                List of table lines

            """

            # See "else" clause below for explanation of start_line and position_line
            start_line = core._get_line_index(self.start_line, self.process_lines(lines))
            position_line = core._get_line_index(self.position_line, self.process_lines(lines))

            # If start_line is none then there is no header line.  Column positions are
            # determined from first data line and column names are either supplied by user
            # or auto-generated.
            if start_line is None:
                if position_line is not None:
                    raise ValueError("Cannot set position_line without also setting header_start")
                data_lines = self.data.process_lines(lines)
                if not data_lines:
                    raise InconsistentTableError(
                        'No data lines found so cannot autogenerate column names')
                vals, starts, ends = self.get_fixedwidth_params(data_lines[0])

                self.names = [self.auto_format % i for i in range(1, len(vals) + 1)]

            else:
                # This bit of code handles two cases:
                # start_line = <index> and position_line = None
                #    Single header line where that line is used to determine both the
                #    column positions and names.
                # start_line = <index> and position_line = <index2>
                #    Two header lines where the first line defines the column names and
                #    the second line defines the column positions

                if position_line is not None:
                    # Define self.col_starts and self.col_ends so that the call to
                    # get_fixedwidth_params below will use those to find the header
                    # column names.  Note that get_fixedwidth_params returns Python
                    # slice col_ends but expects inclusive col_ends on input (for
                    # more intuitive user interface).
                    line = self.get_line(lines, position_line)
                    if len(set(line) - set([self.splitter.delimiter, ' '])) != 1:
                        raise InconsistentTableError('Position line should only contain delimiters and one other character, e.g. "--- ------- ---".')
                        # The line above lies. It accepts white space as well.
                        # We don't want to encourage using three different
                        # characters, because that can cause ambiguities, but white
                        # spaces are so common everywhere that practicality beats
                        # purity here.
                    charset = self.set_of_position_line_characters.union(set([self.splitter.delimiter, ' ']))
                    if not set(line).issubset(charset):
                        raise InconsistentTableError('Characters in position line must be part of {0}'.format(charset))
                    vals, self.col_starts, col_ends = self.get_fixedwidth_params(line)
                    self.col_ends = [x - 1 for x in col_ends]

                # Get the header column names and column positions
                line = self.get_line(lines, start_line)
                vals, starts, ends = self.get_fixedwidth_params(line)

                self.names = vals

            self._set_cols_from_names()

            # Set column start and end positions.
            for i, col in enumerate(self.cols):
                col.start = starts[i]
                col.end = ends[i]

        def get_fixedwidth_params(self, line):
            """
            Split ``line`` on the delimiter and determine column values and
            column start and end positions.  This might include null columns with
            zero length (e.g. for ``header row = "| col1 || col2 | col3 |"`` or
            ``header2_row = "----- ------- -----"``).  The null columns are
            stripped out.  Returns the values between delimiters and the
            corresponding start and end positions.

            Parameters
            ----------
            line : str
                Input line

            Returns
            -------
            vals : list
                List of values.
            starts : list
                List of starting indices.
            ends : list
                List of ending indices.

            """

            # If column positions are already specified then just use those.
            # If neither column starts or ends are given, figure out positions
            # between delimiters. Otherwise, either the starts or the ends have
            # been given, so figure out whichever wasn't given.
            if self.col_starts is not None and self.col_ends is not None:
                starts = list(self.col_starts)  # could be any iterable, e.g. np.array
                ends = [x + 1 for x in self.col_ends]  # user supplies inclusive endpoint
                if len(starts) != len(ends):
                    raise ValueError('Fixed width col_starts and col_ends must have the same length')
                vals = [line[start:end].strip() for start, end in zip(starts, ends)]
            elif self.col_starts is None and self.col_ends is None:
                # There might be a cleaner way to do this but it works...
                vals = line.split(self.splitter.delimiter)
                starts = [0]
                ends = []
                for val in vals:
                    if val:
                        ends.append(starts[-1] + len(val))
                        starts.append(ends[-1] + 1)
                    else:
                        starts[-1] += 1
                starts = starts[:-1]
                vals = [x.strip() for x in vals if x]
                if len(vals) != len(starts) or len(vals) != len(ends):
                    raise InconsistentTableError('Error parsing fixed width header')
            else:
                # exactly one of col_starts or col_ends is given...
                if self.col_starts is not None:
                    starts = list(self.col_starts)
                    ends = starts[1:] + [None] # Assume each col ends where the next starts
                else: # self.col_ends is not None
                    ends = [x + 1 for x in self.col_ends]
                    starts = [0] + ends[:-1] # Assume each col starts where the last ended
                vals = [line[start:end].strip() for start, end in zip(starts, ends)]

            return vals, starts, ends

        def write(self, lines):
            # Header line not written until data are formatted.  Until then it is
            # not known how wide each column will be for fixed width.
            pass

    class FixedWidthData(basic.BasicData):
        """
        Base table data reader.
        """
        splitter_class = FixedWidthSplitter
        """ Splitter class for splitting data lines into columns """

        def write(self, lines):
            vals_list = []
            col_str_iters = self.str_vals()
            for vals in zip(*col_str_iters):
                vals_list.append(vals)

            for i, col in enumerate(self.cols):
                col.width = max([len(vals[i]) for vals in vals_list])
                if self.header.start_line is not None:
                    col.width = max(col.width, len(col.info.name))

            widths = [col.width for col in self.cols]

            if self.header.start_line is not None:
                lines.append(self.splitter.join([col.info.name for col in self.cols],
                                                widths))

            if self.header.position_line is not None:
                char = self.header.position_char
                if len(char) != 1:
                    raise ValueError('Position_char="%s" must be a single character' % char)
                vals = [char * col.width for col in self.cols]
                lines.append(self.splitter.join(vals, widths))

            for vals in vals_list:
                lines.append(self.splitter.join(vals, widths))

            return lines

    class FixedWidth(basic.Basic):
        """
        Read or write a fixed width table with a single header line that defines column
        names and positions.  Examples::

          # Bar delimiter in header and data

          |  Col1 |   Col2      |  Col3 |
          |  1.2  | hello there |     3 |
          |  2.4  | many words  |     7 |

          # Bar delimiter in header only

          Col1 |   Col2      | Col3
          1.2    hello there    3
          2.4    many words     7

          # No delimiter with column positions specified as input

          Col1       Col2Col3
           1.2hello there   3
           2.4many words    7

        See the :ref:`fixed_width_gallery` for specific usage examples.

        """
        _format_name = 'fixed_width'
        _description = 'Fixed width'

        header_class = FixedWidthHeader
        data_class = FixedWidthData

        def __init__(self, col_starts=None, col_ends=None, delimiter_pad=' ', bookend=True):
            super(FixedWidth, self).__init__()
            self.data.splitter.delimiter_pad = delimiter_pad
            self.data.splitter.bookend = bookend
            self.header.col_starts = col_starts
            self.header.col_ends = col_ends

    class FixedWidthNoHeaderHeader(FixedWidthHeader):
        '''Header reader for fixed with tables with no header line'''
        start_line = None

    class FixedWidthNoHeaderData(FixedWidthData):
        '''Data reader for fixed width tables with no header line'''
        start_line = 0

    class FixedWidthNoHeader(FixedWidth):
        """
        Read or write a fixed width table which has no header line.  Column
        names are either input (``names`` keyword) or auto-generated.  Column
        positions are determined either by input (``col_starts`` and ``col_stops``
        keywords) or by splitting the first data line.  In the latter case a
        ``delimiter`` is required to split the data line.

        Examples::

          # Bar delimiter in header and data

          |  1.2  | hello there |     3 |
          |  2.4  | many words  |     7 |

          # Compact table having no delimiter and column positions specified as input

          1.2hello there3
          2.4many words 7

        This class is just a convenience wrapper around the ``FixedWidth`` reader
        but with ``header.start_line = None`` and ``data.start_line = 0``.

        See the :ref:`fixed_width_gallery` for specific usage examples.

        """
        _format_name = 'fixed_width_no_header'
        _description = 'Fixed width with no header'
        header_class = FixedWidthNoHeaderHeader
        data_class = FixedWidthNoHeaderData

        def __init__(self, col_starts=None, col_ends=None, delimiter_pad=' ', bookend=True):
            super(FixedWidthNoHeader, self).__init__(col_starts, col_ends,
                                delimiter_pad=delimiter_pad, bookend=bookend)

    class FixedWidthTwoLineHeader(FixedWidthHeader):
        '''Header reader for fixed width tables splitting on whitespace.

        For fixed width tables with several header lines, there is typically
        a white-space delimited format line, so splitting on white space is
        needed.
        '''
        splitter_class = DefaultSplitter

    class FixedWidthTwoLineDataSplitter(FixedWidthSplitter):
        '''Splitter for fixed width tables splitting on ``' '``.'''
        delimiter = ' '

    class FixedWidthTwoLineData(FixedWidthData):
        '''Data reader for fixed with tables with two header lines.'''
        splitter_class = FixedWidthTwoLineDataSplitter

    class FixedWidthTwoLine(FixedWidth):
        """
        Read or write a fixed width table which has two header lines.  The first
        header line defines the column names and the second implicitly defines the
        column positions.  Examples::

          # Typical case with column extent defined by ---- under column names.

           col1    col2         <== header_start = 0
          -----  ------------   <== position_line = 1, position_char = "-"
            1     bee flies     <== data_start = 2
            2     fish swims

          # Pretty-printed table

          +------+------------+
          | Col1 |   Col2     |
          +------+------------+
          |  1.2 | "hello"    |
          |  2.4 | there world|
          +------+------------+

        See the :ref:`fixed_width_gallery` for specific usage examples.

        """
        _format_name = 'fixed_width_two_line'
        _description = 'Fixed width with second header line'
        data_class = FixedWidthTwoLineData
        header_class = FixedWidthTwoLineHeader

        def __init__(self, position_line=1, position_char='-', delimiter_pad=None, bookend=False):
            super(FixedWidthTwoLine, self).__init__(delimiter_pad=delimiter_pad, bookend=bookend)
            self.header.position_line = position_line
            self.header.position_char = position_char
            self.data.start_line = position_line + 1