function [I, times] = convints(c,t,preCode)
% function [i, times] = convints(c, t, preCode)
%
% c       The encodes in the cortex data file you would like to extract
%         floating point information from
% t       The times that the corresponding encodes were output
% preCode Optional argument that causes the program to extract only the
%         integers which follow this encoded value. This allows you to
%         "mark" different integers as having different meanings in the
%         data file.
% 
% Given a set of Matlab encode values and their times,
% read out the integer numbers and store them in the array i,
% along with their time of occurrence. This code is used to extract
% information embedded in the data file with the routines in "extenc.h"
% and "extenc.c"
% 
% If preCode is given, then only get integers which follow
% preCode in the data. Effectively, this replaces INT_MARKER
% with preCode.
%
% Because of the way Cortex encodes things, intervening codes can be
% mixed with integer data. You must be careful to never have
% two threads running which both try to encode integer values,
% as the resulting data file can intermingle the bytes of two separate
% ints, making it impossible to later decode.
%
% This code needs access to either a global structure Encodes, or
% an m-file called 'encodes.m' that creates the structure.
%
% Version 1.0
% For additional code, updated versions, questions or comments, please refer
% to the Active Perception Lab home page
%            http://www.cnbc.cmu.edu/~tai/lab.html


% Copyright 1998-1999
% Rick Romero
% rickr+@cmu.edu
% Permission to use and modify is granted,
% but not to redistribute original or modified code.

% Assumes that ints are coded as follows:
% All floats are marked by a INT_MARKER (127) before the float data
% The float data is encoded using four encodes, ENCODE_INT[1-4] in
% increasing order of byte number.

% Some encode values, just so we have them
if (exist('Encodes') == 0)
  global Encodes
  evalin('caller','global Encodes;encodes');
end

if (nargin < 3)
  preCode = Encodes.INT_MARKER;
end


which = find(c == preCode);
times = t(which);
numints = prod(size(which));
I = zeros(numints, 1);

for i=1:numints
  if (i == numints)
    cndx = which(i):prod(size(c));
  else
    cndx = which(i):(which(i+1)-1);
  end
  cc = c(cndx);
  cencodes = find((cc >= Encodes.ENCODE_INT1) & ...
                  (cc < Encodes.ENCODE_INT4 + 256));
  if (prod(size(cencodes)) < 4)
    error('Problem reading in float data--wrong number of markers');
  end
  if ((cc(cencodes(1)) >= Encodes.ENCODE_INT2) | ...
      (cc(cencodes(2)) >= Encodes.ENCODE_INT3) | ...
      (cc(cencodes(3)) >= Encodes.ENCODE_INT4) | ...
      (cc(cencodes(4)) <  Encodes.ENCODE_INT4) | ...
      (cc(cencodes(3)) <  Encodes.ENCODE_INT3) | ...
      (cc(cencodes(2)) <  Encodes.ENCODE_INT2))
    errmsg =  sprintf('Out of order float data: received following encodes (0x%X 0x%X 0x%X 0x%X)', cc(cencodes(1)), cc(cencodes(2)), cc(cencodes(3)), cc(cencodes(4)));
    error(errmsg);
  end

  cencodes = cc(cencodes(1:4));
  cencodes = fliplr(bitand(cencodes, 255));
  if (cencodes(1) > 127)
    fsign = -1;
  else
    fsign = 1;
  end
  I(i) = sum(([256 256 256 256] .^ [3 2 1 0]) .* cencodes);
  if (I(i) >= (128 * (256 ^ 3)))
    I(i) = I(i) - 256 * (256 ^ 3);
  end
    
end