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Slepi/Code/Utilities/spm12/external/mne/fiff_read_raw_segment.m
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fiff_read_raw_segment.m
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function [data,times] = fiff_read_raw_segment(raw,from,to,sel)
%
% [data,times] = fiff_read_raw_segment(raw,from,to,sel)
%
% Read a specific raw data segment
%
% raw - structure returned by fiff_setup_read_raw
% from - first sample to include. If omitted, defaults to the
% first sample in data
% to - last sample to include. If omitted, defaults to the last
% sample in data
% sel - optional channel selection vector
%
% data - returns the data matrix (channels x samples)
% times - returns the time values corresponding to the samples (optional)
%
%
% Author : Matti Hamalainen, MGH Martinos Center
% License : BSD 3-clause
%
% Revision 1.9 2007/11/22 05:04:25 msh
% Fixed help text and some error checking
%
% Revision 1.8 2006/04/23 15:29:40 msh
% Added MGH to the copyright
%
% Revision 1.7 2006/04/21 22:11:34 msh
% Times calculation needed casting to double
%
% Revision 1.6 2006/04/21 22:03:43 msh
% Fixed time limit output.
%
% Revision 1.5 2006/04/21 16:17:48 msh
% Added handling of CTF compensation
%
% Revision 1.4 2006/04/21 15:11:56 msh
% Made the debug output optional.
%
% Revision 1.3 2006/04/21 14:43:59 msh
% Report projection operators.
% Some more checks in raw data reading.
%
% Revision 1.2 2006/04/21 14:23:16 msh
% Further improvements in raw data reading
%
%
me='MNE:fiff_read_raw_segment';
if nargin == 3
sel = [];
elseif nargin == 2
to = raw.last_samp;
sel = [];
elseif nargin == 1
from = raw.first_samp;
to = raw.last_samp;
sel = [];
elseif nargin ~= 4
error(me,'Incorrect number of arguments');
end
%
% Initial checks
%
from = double(from);
to = double(to);
if from < raw.first_samp
from = raw.first_samp;
end
if to > raw.last_samp
to = raw.last_samp;
end
%
if from > to
error(me,'No data in this range');
end
fprintf(1,'Reading %d ... %d = %9.3f ... %9.3f secs...', ...
from,to,from/raw.info.sfreq,to/raw.info.sfreq);
%
% Initialize the data and calibration vector
%
nchan = raw.info.nchan;
dest = 1;
cal = diag(raw.cals);
%
if isempty(sel)
data = zeros(nchan,to-from+1);
if isempty(raw.proj) && isempty(raw.comp)
mult = [];
else
if isempty(raw.proj)
mult = raw.comp*cal;
elseif isempty(raw.comp)
mult = raw.proj*cal;
else
mult = raw.proj*raw.comp*cal;
end
end
else
data = zeros(length(sel),to-from+1);
if isempty(raw.proj) && isempty(raw.comp)
mult = [];
cal = diag(raw.cals(sel));
else
if isempty(raw.proj)
mult = raw.comp(sel,:)*cal;
elseif isempty(raw.comp)
mult = raw.proj(sel,:)*cal;
else
mult = raw.proj(sel,:)*raw.comp*cal;
end
end
end
do_debug=false;
if ~isempty(cal)
cal = sparse(cal);
end
if ~isempty(mult)
mult = sparse(mult);
end
if isempty(fopen(raw.fid))
fid = fopen(raw.info.filename,'rb','ieee-be');
if (fid < 0)
error(me,'Cannot open file %s',raw.info.filename);
end
else
fid = raw.fid;
end
for k = 1:length(raw.rawdir)
this = raw.rawdir(k);
%
% Do we need this buffer
%
if this.last > from
if isempty(this.ent)
%
% Take the easy route: skip is translated to zeros
%
if do_debug
fprintf(1,'S');
end
doing_whole = false;
if isempty(sel)
one = zeros(nchan,this.nsamp);
else
one = zeros(length(sel),this.nsamp);
end
else
tag = fiff_read_tag(fid,this.ent.pos);
%
% Depending on the state of the projection and selection
% we proceed a little bit differently
%
if isempty(mult)
if isempty(sel)
one = cal*double(reshape(tag.data,nchan,this.nsamp));
else
one = double(reshape(tag.data,nchan,this.nsamp));
one = cal*one(sel,:);
end
else
one = mult*double(reshape(tag.data,nchan,this.nsamp));
end
end
%
% The picking logic is a bit complicated
%
if to >= this.last && from <= this.first
%
% We need the whole buffer
%
first_pick = 1;
last_pick = this.nsamp;
if do_debug
fprintf(1,'W');
end
elseif from > this.first
first_pick = from - this.first + 1;
if to < this.last
%
% Something from the middle
%
last_pick = this.nsamp + to - this.last;
if do_debug
fprintf(1,'M');
end
else
%
% From the middle to the end
%
last_pick = this.nsamp;
if do_debug
fprintf(1,'E');
end
end
else
%
% From the beginning to the middle
%
first_pick = 1;
last_pick = to - this.first + 1;
if do_debug
fprintf(1,'B');
end
end
%
% Now we are ready to pick
%
picksamp = last_pick - first_pick + 1;
if picksamp > 0
data(:,dest:dest+picksamp-1) = one(:,first_pick:last_pick);
dest = dest + picksamp;
end
end
%
% Done?
%
if this.last >= to
fprintf(1,' [done]\n');
break;
end
end
fclose(fid);
if nargout == 2
times = [ from:to ];
times = double(times)/raw.info.sfreq;
end
return;
end
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