NIMSreadHeader.m

function [Header,nHeader,HZ] = NIMSreadHeader(fname,index)

% [Header,nHeader,HZ] = NIMSreadHeader(fname,index)
% 
% Reads the header from a raw NIMS binary file
% and outputs the length of the header and the header.
% Uses the optional array 'index' of possible block lengths
% that might follow the 01 byte at the end of the header.
% Currently these are 25 for 1 Hz data, 131 for 8 Hz.
% Outputs HZ=1 or HZ=8, respectively.

if nargin < 2
    index = 1:1:255;
end

fid = fopen(fname,'r');

nHeader = 0;
Header = zeros(1,1000);

fseek(fid,nHeader,'bof')
Header(1) = fread(fid,1,'uchar');
Header(2) = fread(fid,1,'uchar');

i = 2;
while ~ (Header(i-1)==1 && max(index==Header(i)))
    i = i + 1;
    [temp,count] = fread(fid,1,'uchar');
    if count == 0        
        i=i-1
       break
    end
    Header(i) = temp;
end

nBlk = Header(i);

if isstrprop(char(Header(i-1)),'alphanum')
    % usually true for hdr.fix
    nHeader = i-1;
else
    % usually true for reading from DATA.BIN
    nHeader = i-2;
end
Header = Header(1:nHeader);

fclose(fid)

switch nBlk
    case 8*16+3 % 8 hz (83h)
        HZ = 8;
    case 1*16+9 % 1 hz (19h)
        HZ = 1;
    otherwise
        fprintf(1,'Error: unknown length of block %d',nBlk);
        fprintf(1,'Error: assume 1 HZ data by default');
        HZ = 1;
end