function output = hex2uint8(instr)
% HEX2UINT8 -- Hexidecimal string converter.
% Converts hexdecimal ascii into unsigned 8 bit integer.
% 
% Use as: hex2uint8(instr)
% Inputs: instr = string of hex characters
% Output: output = a vector of integers which can be converted
%         into characters by using char(output)
%
% Created by K.M. Flynn
% Documented by E.Palomino; 20 Sep 2000
% Re-written for speed by M.Godin; 03 Aug 2004

% Version prior to 03 Aug 2004:
%n = length(instr)/2;
%tmpstr = double(instr) - 48;
%tmpstr(find(tmpstr>9)) = tmpstr(find(tmpstr>9)) - 7;
%tmpstr(find(tmpstr>15)) = tmpstr(find(tmpstr>15)) - 32;
%tmpout = [];
%for i=1:n
%   j=2*(i-1)+1;
%   tmpout(i) = 16*tmpstr(j) + tmpstr(j+1);
%end
%output = tmpout;

% High-speed version
output = hex2dec(reshape(instr,2,length(instr)/2)')';