function [outsig,fb]=filterbank_block(insig,fb)
%FILTERBANK_BLOCK  Process signal block in a filterbank
%   Usage: [outsig,fb]=filterbank(fb,insig);
%
%   [outsig,fb]=FILTERBANK_BLOCK(insig,fb) filters a block of input using the
%   filters described in the structrure fb. The structure fb must first
%   have been created using FILTERBANK_INIT.
%
%   If insig is a matrix then filtering is applied along the columns. In
%   this case, the output will be 3-dimensional. First dimension
%   is time, second dimension is frequency channel and third dimension
%   corresponds to the columns of the input signal.
%
%   See also: filterbank_init, ufilterbankz
%
%   Url: http://amtoolbox.sourceforge.net/amt-0.9.5/doc/filters/filterbank_block.php

% Copyright (C) 2009-2014 Peter L. Søndergaard.
% This file is part of AMToolbox version 1.0.0
%
% This program 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.
%
% This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
  
%   AUTHOR : Peter L. Søndergaard

% ------ Checking of input parameters ---------  

error(nargchk(2,2,nargin));


% ------ Computation --------------------------

siglen=size(insig,1);

if rem(siglen,fb.hopsize)~=0
  error(['FILTERBANK_BLOCK: The hopsize must divide the length of the ' ...
         'input block.']);
end;

fb.outlen=ceil(siglen/fb.hopsize);

outsig=zeros(fb.outlen,fb.nchannels,fb.nsigs);

for ii=1:fb.nchannels
  [res,fb.zi(:,:,ii)] = filter(fb.b(ii,:),fb.a(ii,:),insig,squeeze(fb.zi(:,:,ii)));
  res = res(1:fb.hopsize:siglen,:);  
  outsig(:,ii,:) = reshape(res,fb.outlen,1,fb.nsigs);
end;

fb.outstart = fb.outend+1;
fb.outend   = fb.outstart+fb.outlen-1;