Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / dataframe-0.9.1 / @dataframe / private / df_cow.m

diff --git a/octave_packages/dataframe-0.9.1/@dataframe/private/df_cow.m b/octave_packages/dataframe-0.9.1/@dataframe/private/df_cow.m
new file mode 100644 (file)
index 0000000..433c00e
--- /dev/null
+++ b/octave_packages/dataframe-0.9.1/@dataframe/private/df_cow.m
@@ -0,0 +1,78 @@
+function [df, S] = df_cow(df, S, col)
+
+  %# function [resu, S] = df_cow(df, S, col)
+  %# Implements Copy-On-Write on dataframe. If one or more columns
+  %# specified in inds is aliased to another one, duplicate it and
+  %# adjust the repetition index to remove the aliasing
+
+  %% Copyright (C) 2009-2012 Pascal Dupuis <Pascal.Dupuis@uclouvain.be>
+  %%
+  %% 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 2, 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,
+  %% write to the Free Software Foundation, 51 Franklin Street -
+  %% Fifth Floor, Boston, MA 02110-1301, USA.
+  
+  %#
+  %# $Id: df_cow.m 9585 2012-02-05 15:32:46Z cdemills $
+  %#
+
+  if length(col) > 1,
+    error("df_cow must work on a column-by-column basis");
+  endif
+  
+  if (1 == length(S.subs)),
+    inds = 1; 
+  else
+    inds = S.subs{2};
+  endif
+
+  if (!isnumeric(inds)), 
+    if !strcmp(inds, ':'),
+      error("Unknown sheet selector %s", inds);
+    endif
+    inds = 1:length(df._rep(col));
+  endif
+
+  for indi = inds(:).',
+    dummy = df._rep{col}; dummy(indi) = 0;
+    [t1, t2] = ismember(df._rep{col}(indi)(:), dummy);
+    for indj = t2(find(t2)), %# Copy-On-Write
+      %# determines the index for the next column
+      t1 = 1+max(df._rep{col}); 
+      %# duplicate the touched column
+      df._data{col} = horzcat(df._data{col}, \
+                              df._data{col}(:, df._rep{col}(indj)));  
+      if (indi > 1),
+        %# a new column has been created
+        df._rep{col}(indi) = t1;
+      else
+        %# update repetition index aliasing this one
+        df._rep{col}(find(dummy == indi)) = t1;
+      endif
+    endfor
+  endfor
+
+  %# reorder S
+  if (length(S.subs) > 1),
+    if (S.subs{2} != 1 || length(S.subs{2}) > 1), 
+      %# adapt sheet index according to df_rep
+      S.subs{2} = df._rep{col}(S.subs{2});
+    endif
+  endif
+
+  df = df_thirddim(df);
+
+endfunction