/*

Copyright (C) 2008-2015 Jonathan Stickel
Copyright (C) 2010 Jaroslav Hajek

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

// Adapted from previous version of dlmread.occ as authored by Kai
// Habel, but core code has been completely re-written.

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <cctype>
#include <fstream>
#include <limits>

#include "file-ops.h"
#include "lo-ieee.h"

#include "defun.h"
#include "oct-stream.h"
#include "error.h"
#include "ovl.h"
#include "utils.h"

static const octave_idx_type idx_max =
  std::numeric_limits<octave_idx_type>::max ();

static bool
read_cell_spec (std::istream& is, octave_idx_type& row, octave_idx_type& col)
{
  bool stat = false;

  if (is.peek () == std::istream::traits_type::eof ())
    stat = true;
  else
    {
      if (::isalpha (is.peek ()))
        {
          col = 0;
          while (is && ::isalpha (is.peek ()))
            {
              char ch = is.get ();
              col *= 26;
              if (ch >= 'a')
                col += ch - 'a' + 1;
              else
                col += ch - 'A' + 1;
            }
          col--;

          if (is)
            {
              is >> row;
              row--;
              if (is)
                stat = true;
            }
        }
    }

  return stat;
}

static bool
parse_range_spec (const octave_value& range_spec,
                  octave_idx_type& rlo, octave_idx_type& clo,
                  octave_idx_type& rup, octave_idx_type& cup)
{
  bool stat = true;

  if (range_spec.is_string ())
    {
      std::istringstream is (range_spec.string_value ());
      char ch = is.peek ();

      if (ch == '.' || ch == ':')
        {
          rlo = 0;
          clo = 0;
          ch = is.get ();
          if (ch == '.')
            {
              ch = is.get ();
              if (ch != '.')
                stat = false;
            }
        }
      else
        {
          stat = read_cell_spec (is, rlo, clo);

          if (stat)
            {
              ch = is.peek ();

              if (ch == '.' || ch == ':')
                {
                  ch = is.get ();
                  if (ch == '.')
                    {
                      ch = is.get ();
                      if (! is || ch != '.')
                        stat = false;
                    }

                  rup = idx_max - 1;
                  cup = idx_max - 1;
                }
              else
                {
                  rup = rlo;
                  cup = clo;
                  if (! is || ! is.eof ())
                    stat = false;
                }
            }
        }

      if (stat && is && ! is.eof ())
        stat = read_cell_spec (is, rup, cup);

      if (! is || ! is.eof ())
        stat = false;
    }
  else if (range_spec.is_real_matrix () && range_spec.numel () == 4)
    {
      ColumnVector range(range_spec.vector_value ());
      // double --> unsigned int
      rlo = static_cast<octave_idx_type> (range(0));
      clo = static_cast<octave_idx_type> (range(1));
      rup = static_cast<octave_idx_type> (range(2));
      cup = static_cast<octave_idx_type> (range(3));
    }
  else
    stat = false;

  return stat;
}

DEFUN (dlmread, args, ,
       "-*- texinfo -*-\n\
@deftypefn  {} {@var{data} =} dlmread (@var{file})\n\
@deftypefnx {} {@var{data} =} dlmread (@var{file}, @var{sep})\n\
@deftypefnx {} {@var{data} =} dlmread (@var{file}, @var{sep}, @var{r0}, @var{c0})\n\
@deftypefnx {} {@var{data} =} dlmread (@var{file}, @var{sep}, @var{range})\n\
@deftypefnx {} {@var{data} =} dlmread (@dots{}, \"emptyvalue\", @var{EMPTYVAL})\n\
Read numeric data from the text file @var{file} which uses the delimiter\n\
@var{sep} between data values.\n\
\n\
If @var{sep} is not defined the separator between fields is determined from\n\
the file itself.\n\
\n\
The optional scalar arguments @var{r0} and @var{c0} define the starting row\n\
and column of the data to be read.  These values are indexed from zero,\n\
i.e., the first data row corresponds to an index of zero.\n\
\n\
The @var{range} parameter specifies exactly which data elements are read.\n\
The first form of the parameter is a 4-element vector containing the upper\n\
left and lower right corners @code{[@var{R0},@var{C0},@var{R1},@var{C1}]}\n\
where the indices are zero-based.  Alternatively, a spreadsheet style\n\
form such as @qcode{\"A2..Q15\"} or @qcode{\"T1:AA5\"} can be used.  The\n\
lowest alphabetical index @qcode{'A'} refers to the first column.  The\n\
lowest row index is 1.\n\
\n\
@var{file} should be a filename or a file id given by @code{fopen}.  In the\n\
latter case, the file is read until end of file is reached.\n\
\n\
The @qcode{\"emptyvalue\"} option may be used to specify the value used to\n\
fill empty fields.  The default is zero.  Note that any non-numeric values,\n\
such as text, are also replaced by the @qcode{\"emptyvalue\"}.\n\
@seealso{csvread, textscan, textread, dlmwrite}\n\
@end deftypefn")
{
  int nargin = args.length ();

  double empty_value = 0.0;

  if (nargin > 2 && args(nargin-2).is_string ()
      && args(nargin-2).string_value () == "emptyvalue")
    {
      empty_value = args(nargin-1).double_value ();

      nargin -= 2;
    }

  if (nargin < 1 || nargin > 4)
    print_usage ();

  std::istream *input = 0;
  std::ifstream input_file;

  if (args(0).is_string ())
    {
      // Filename.
      std::string fname (args(0).string_value ());

      std::string tname = file_ops::tilde_expand (fname);

      tname = find_data_file_in_load_path ("dlmread", fname);

      input_file.open (tname.c_str (), std::ios::in);

      if (! input_file)
        error ("dlmread: unable to open file '%s'", fname.c_str ());

      input = &input_file;
    }
  else if (args(0).is_scalar_type ())
    {
      octave_stream is = octave_stream_list::lookup (args(0), "dlmread");

      input = is.input_stream ();

      if (! input)
        error ("dlmread: stream FILE not open for input");
    }
  else
    error ("dlmread: FILE argument must be a string or file id");

  // Set default separator.
  std::string sep;
  if (nargin > 1)
    {
      if (args(1).is_sq_string ())
        sep = do_string_escapes (args(1).string_value ());
      else
        sep = args(1).string_value ();
    }

  // Take a subset if a range was given.
  octave_idx_type r0 = 0;
  octave_idx_type c0 = 0;
  octave_idx_type r1 = idx_max-1;
  octave_idx_type c1 = idx_max-1;
  if (nargin > 2)
    {
      if (nargin == 3)
        {
          if (! parse_range_spec (args(2), r0, c0, r1, c1))
            error ("dlmread: error parsing RANGE");
        }
      else if (nargin == 4)
        {
          r0 = args(2).idx_type_value ();
          c0 = args(3).idx_type_value ();
        }

      if (r0 < 0 || c0 < 0)
        error ("dlmread: left & top must be positive");
    }

  octave_idx_type i = 0;
  octave_idx_type j = 0;
  octave_idx_type r = 1;
  octave_idx_type c = 1;
  octave_idx_type rmax = 0;
  octave_idx_type cmax = 0;

  Matrix rdata;
  ComplexMatrix cdata;

  bool iscmplx = false;
  bool sepflag = false;

  std::string line;

  // Skip the r0 leading lines as these might be a header.
  for (octave_idx_type m = 0; m < r0; m++)
    getline (*input, line);
  r1 -= r0;

  std::istringstream tmp_stream;

  // Read in the data one field at a time, growing the data matrix
  // as needed.
  while (getline (*input, line))
    {
      // Skip blank lines for compatibility.
      if (line.find_first_not_of (" \t") == std::string::npos)
        continue;

      // To be compatible with matlab, blank separator should
      // correspond to whitespace as delimter.
      if (! sep.length ())
        {
          size_t n = line.find_first_of (",:; \t",
                                         line.find_first_of ("0123456789"));
          if (n == std::string::npos)
            {
              sep = " \t";
              sepflag = true;
            }
          else
            {
              char ch = line.at (n);

              switch (line.at (n))
                {
                case ' ':
                case '\t':
                  sepflag = true;
                  sep = " \t";
                  break;

                default:
                  sep = ch;
                  break;
                }
            }
        }

      if (cmax == 0)
        {
          // Try to estimate the number of columns.  Skip leading
          // whitespace.
          size_t pos1 = line.find_first_not_of (" \t");
          do
            {
              size_t pos2 = line.find_first_of (sep, pos1);

              if (sepflag && pos2 != std::string::npos)
                // Treat consecutive separators as one.
                {
                  pos2 = line.find_first_not_of (sep, pos2);
                  if (pos2 != std::string::npos)
                    pos2 -= 1;
                  else
                    pos2 = line.length () - 1;
                }

              cmax++;

              if (pos2 != std::string::npos)
                pos1 = pos2 + 1;
              else
                pos1 = std::string::npos;

            }
          while (pos1 != std::string::npos);

          if (iscmplx)
            cdata.resize (rmax, cmax);
          else
            rdata.resize (rmax, cmax);
        }

      r = (r > i + 1 ? r : i + 1);
      j = 0;
      // Skip leading whitespace.
      size_t pos1 = line.find_first_not_of (" \t");
      do
        {
          octave_quit ();

          size_t pos2 = line.find_first_of (sep, pos1);
          std::string str = line.substr (pos1, pos2 - pos1);

          if (sepflag && pos2 != std::string::npos)
            // Treat consecutive separators as one.
            pos2 = line.find_first_not_of (sep, pos2) - 1;

          c = (c > j + 1 ? c : j + 1);
          if (r > rmax || c > cmax)
            {
              // Use resize_and_fill for the case of not-equal
              // length rows.
              rmax = 2*r;
              cmax = c;
              if (iscmplx)
                cdata.resize (rmax, cmax);
              else
                rdata.resize (rmax, cmax);
            }

          tmp_stream.str (str);
          tmp_stream.clear ();

          double x = octave_read_double (tmp_stream);
          if (tmp_stream)
            {
              if (tmp_stream.eof ())
                {
                  if (iscmplx)
                    cdata(i,j++) = x;
                  else
                    rdata(i,j++) = x;
                }
              else if (std::toupper (tmp_stream.peek ()) == 'I')
                {
                  // This is to allow pure imaginary numbers.
                  if (iscmplx)
                    cdata(i,j++) = x;
                  else
                    rdata(i,j++) = x;
                }
              else
                {
                  double y = octave_read_double (tmp_stream);

                  if (! iscmplx && y != 0.)
                    {
                      iscmplx = true;
                      cdata = ComplexMatrix (rdata);
                    }

                  if (iscmplx)
                    cdata(i,j++) = Complex (x, y);
                  else
                    rdata(i,j++) = x;
                }
            }
          else if (iscmplx)
            cdata(i,j++) = empty_value;
          else
            rdata(i,j++) = empty_value;

          if (pos2 != std::string::npos)
            pos1 = pos2 + 1;
          else
            pos1 = std::string::npos;

        }
      while (pos1 != std::string::npos);

      if (i == r1)
        break;

      i++;
    }

  if (r1 >= r)
    r1 = r - 1;
  if (c1 >= c)
    c1 = c - 1;

  // Now take the subset of the matrix if there are any values.
  if (i > 0 || j > 0)
    {
      if (iscmplx)
        cdata = cdata.extract (0, c0, r1, c1);
      else
        rdata = rdata.extract (0, c0, r1, c1);
    }

  if (iscmplx)
    return ovl (cdata);
  else
    return ovl (rdata);
}

/*
%!shared file
%! file = tempname ();
%! fid = fopen (file, "wt");
%! fwrite (fid, "1, 2, 3\n4, 5, 6\n7, 8, 9\n10, 11, 12");
%! fclose (fid);

%!assert (dlmread (file), [1, 2, 3; 4, 5, 6; 7, 8, 9;10, 11, 12])
%!assert (dlmread (file, ","), [1, 2, 3; 4, 5, 6; 7, 8, 9; 10, 11, 12])
%!assert (dlmread (file, ",", [1, 0, 2, 1]), [4, 5; 7, 8])
%!assert (dlmread (file, ",", "B1..C2"), [2, 3; 5, 6])
%!assert (dlmread (file, ",", "B1:C2"), [2, 3; 5, 6])
%!assert (dlmread (file, ",", "..C2"), [1, 2, 3; 4, 5, 6])
%!assert (dlmread (file, ",", 0, 1), [2, 3; 5, 6; 8, 9; 11, 12])
%!assert (dlmread (file, ",", "B1.."), [2, 3; 5, 6; 8, 9; 11, 12])
%!error (dlmread (file, ",", [0 1]))

%!test
%! unlink (file);

%!shared file
%! file = tempname ();
%! fid = fopen (file, "wt");
%! fwrite (fid, "1, 2, 3\n4+4i, 5, 6\n7, 8, 9\n10, 11, 12");
%! fclose (fid);

%!assert (dlmread (file), [1, 2, 3; 4 + 4i, 5, 6; 7, 8, 9; 10, 11, 12])
%!assert (dlmread (file, ","), [1, 2, 3; 4 + 4i, 5, 6; 7, 8, 9; 10, 11, 12])
%!assert (dlmread (file, ",", [1, 0, 2, 1]), [4 + 4i, 5; 7, 8])
%!assert (dlmread (file, ",", "A2..B3"), [4 + 4i, 5; 7, 8])
%!assert (dlmread (file, ",", "A2:B3"), [4 + 4i, 5; 7, 8])
%!assert (dlmread (file, ",", "..B3"), [1, 2; 4 + 4i, 5; 7, 8])
%!assert (dlmread (file, ",", 1, 0), [4 + 4i, 5, 6; 7, 8, 9; 10, 11, 12])
%!assert (dlmread (file, ",", "A2.."), [4 + 4i, 5, 6; 7, 8, 9; 10, 11, 12])
%!error (dlmread (file, ",", [0 1]))

%!test
%! unlink (file);
*/