Hexadecimal to binary

The hex2bin function in MATLAB is used to convert a hexadecimal string to a binary string.

function s= hex2bin(h,N)

%HEX2BIN Convert hexdecimal string to a binary string.

% HEX2BIN(h) returns the binary representation of h as a string.

%

% Author :Tamir Suliman

% Revision of the matlab functions

% HEX2BIN(h,n) produces a binary representation with at least

% N bits.

% used some codes from hex2dc function

% Example

% hex2bin('f') returns '1111'

% hex2bin('fa') returns '1111 1010'

% hex2bin(['f' 'a'],4) returns

% 0010 1111

% See also BIN2DEC, DEC2HEX, DEC2BASE.

%

% This function implemented with the help of hex2dec and dec2bin

%

% Input checking

%

h=h(:); % Make sure h is a column vector.

if iscellstr(h), h = char(h); end

if isempty(h), s = []; return, end

% Work in upper case.

h = upper(h);

[m,n]=size(h);

% Right justify strings and form 2-D character array.

if ~isempty(find((h==' ' | h==0),1))

h = strjust(h);

% Replace any leading blanks and nulls by 0.

h(cumsum(h ~= ' ' & h ~= 0,2) == 0) = '0';

else

h = reshape(h,m,n);

end

% Check for out of range values

if any(any(~((h>='0' & h<='9') | (h>='A'&h<='F'))))

error('MATLAB:hex2bin:IllegalHexadecimal',...

'Input string found with characters other than 0-9, a-f, or A-F.');

end

sixteen = 16;

p = fliplr(cumprod([1 sixteen(ones(1,n-1))]));

p = p(ones(m,1),:);

s = h <= 64; % Numbers

h(s) = h(s) - 48;

s = h > 64; % Letters

h(s) = h(s) - 55;

s = sum(h.*p,2);

% Decimal to Binary

d = s;

if nargin<2

N = 2; % Default value of N is 2.

else

if ~(isnumeric(N) || ischar(N)) || ~isscalar(N) || N<0

error('MATLAB:hex2bin:InvalidBitArg','N must be a positive scalar numeric.');

end

N = round(double(N)); % Make sure N is an integer.

end;

% Actual algorithm

[f,e] = log2(max(d)); % How many digits do we need to represent the numbers?

N = max(N, e); % Use the larger of N and e.

s = char(rem(floor(d*pow2(1-N:0)),2)+'0');