function y = wshift(type,x,p)
%WSHIFT Shift Vector or Matrix.
% Y = WSHIFT(TYPE,X,P) with TYPE = {1,'1','1d' or '1D'}
% performs a P-circular shift of vector X.
% The shift P must be an integer, positive for right to left
% shift and negative for left to right shift.
%
% Y = WSHIFT(TYPE,X,P) with TYPE = {2,'2','2d' or '2D'}
% performs a P-circular shift of matrix X.
% The shifts P must be integers. P(1) is the shift for rows
% and P(2) is the shift for columns.
%
% WSHIFT('1D',X) is equivalent to WSHIFT('1D',X,1)
% WSHIFT('2D',X) is equivalent to WSHIFT('2D',X,[1 1])
%
% Example 1D:
% x = [1 2 3 4 5]
% wshift('1D',x,1) = [2 3 4 5 1]
% wshift('1D',x,-1) = [5 1 2 3 4]
%
% Example 2D:
% x = [1 2 3;5 6 7]
% wshift('2D',x,[1 1]) = [6 7 5;2 3 1]
% wshift('2D',x,[-1,0]) = [5 6 7;1 2 3]
% M. Misiti, Y. Misiti, G. Oppenheim, J.M. Poggi 01-Dec-97.
% Last Revision: 01-May-1998.
% Copyright (c) 1995-98 by The MathWorks, Inc.
% $Revision: 1.2 $ $Date: 1998/07/16 14:33:59 $
if isempty(x) | all(p==0) , y = x; return; end
switch type
case {1,'1','1d','1D'}
if nargin<3 , p = 1; end
L = length(x);
p = rem(p,L);
if p<0 , p = L+p; end
y = x([p+1:L,1:p]);
case {2,'2','2d','2D'}
if nargin<3 , p = [1 1]; end
S = size(x);
p = rem(p,S);
k = (p<0);
p(k) = S(k)+p(k);
y = x([p(1)+1:S(1),1:p(1)],[p(2)+1:S(2),1:p(2)]);
end
