## Copyright (C) 2012 Daniel Kraft
##
## 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/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {} profshow (@var{data})
## @deftypefnx {Function File} {} profshow (@var{data}, @var{n})
## Show flat profiler results.
##
## This command prints out profiler data as a flat profile.  @var{data} is the
## structure returned by @code{profile ('info')}.  If @var{n} is given, it
## specifies the number of functions to show in the profile; functions are
## sorted in descending order by total time spent in them.  If there are more
## than @var{n} included in the profile, those will not be shown.  @var{n}
## defaults to 20.
##
## The attribute column shows @samp{R} for recursive functions and nothing
## otherwise.
## @seealso{profexplore, profile}
## @end deftypefn

## Built-in profiler.
## Author: Daniel Kraft <d@domob.eu>

function profshow (data, n = 20)

  if (nargin < 1 || nargin > 2)
    print_usage ();
  endif

  n = fix (n);
  if (! isscalar (n) || ! isreal (n) || ! (n > 0))
    error ("profile: N must be a positive integer");
  endif

  m = length (data.FunctionTable);
  n = min (n, m);

  ## We want to sort by times in descending order.  For this, extract the
  ## times to an array, then sort this, and use the resulting index permutation
  ## to print out our table.
  times = -[ data.FunctionTable.TotalTime ];

  [~, p] = sort (times);

  ## For printing the table, find out the maximum length of a function name
  ## so that we can proportion the table accordingly.  Based on this,
  ## we can build the format used for printing table rows.
  nameLen = length ("Function");
  for i = 1 : n
    nameLen = max (nameLen, length (data.FunctionTable(p(i)).FunctionName));
  endfor
  headerFormat = sprintf ("%%4s %%%ds %%4s %%12s %%12s\n", nameLen);
  rowFormat = sprintf ("%%4d %%%ds %%4s %%12.3f %%12d\n", nameLen);

  printf (headerFormat, "#", "Function", "Attr", "Time (s)", "Calls");
  printf ("%s\n", repmat ("-", 1, nameLen + 2 * 5 + 2 * 13));
  for i = 1 : n
    row = data.FunctionTable(p(i));
    attr = "";
    if (row.IsRecursive)
      attr = "R";
    endif
    printf (rowFormat, p(i), row.FunctionName, attr, ...
            row.TotalTime, row.NumCalls);
  endfor

endfunction

%!demo
%! profile ("on");
%! A = rand (100);
%! B = expm (A);
%! profile ("off");
%! T = profile ("info");
%! profshow (T, 10);

%!demo
%! profile ("on");
%! expm (rand (500) + eye (500));
%! profile ("off");
%! profshow (profile ("info"), 5);

%!error profshow ();
%!error profshow (1, 2, 3);
%!error profshow (struct (), 1.2);