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## Copyright (C) 1996 Kurt Hornik
##
## 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, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.
## usage: findstr (s, t [, overlap])
##
## Returns the vector of all positions in the longer of the two strings
## S and T where an occurence of the shorter of the two starts.
##
## If the optional argument OVERLAP is nonzero, the returned vector
## can include overlapping positions (this is the default).
##
## For example,
##
## findstr ("abababa", "aba") => [1, 3, 5]
## findstr ("abababa", "aba", 0) => [1, 5]
## Author: Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>
## Adapted-By: jwe
function v = findstr (s, t, overlap)
if (nargin < 2 || nargin > 3)
usage ("findstr (s, t [, overlap])");
endif
if (nargin == 2)
overlap = 1;
endif
if (isstr (s) && isstr (t))
## Make S be the longer string.
if (length (s) < length (t))
tmp = s;
s = t;
t = tmp;
endif
s = toascii (s);
t = toascii (t);
l_t = length (t);
ind = 1 : l_t;
limit = length (s) - l_t + 1;
v = zeros (1, limit);
i = 0;
k = 1;
while (k <= limit)
if (s (ind + k - 1) == t)
v (++i) = k;
if (! overlap)
k = k + l_t - 1;
endif
endif
k++;
endwhile
if (i > 0)
v = v (1:i);
else
v = [];
endif
else
error ("findstr: expecting first two arguments to be strings");
endif
endfunction
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