Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / strings-1.1.0 / base64encode.m

diff --git a/octave_packages/strings-1.1.0/base64encode.m b/octave_packages/strings-1.1.0/base64encode.m
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+## Author: Paul Kienzle <pkienzle@users.sf.net>
+## This program is granted to the public domain.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{Y} =} base64encode (@var{X})
+## @deftypefnx {Function File} {@var{Y} =} base64encode (@var{X}, @var{do_reshape})
+## Convert X into string of printable characters according to RFC 2045.
+## The input may be a string or a matrix of integers in the range 0..255.
+## If want the output in the 1-row of strings format, pass the 
+## @var{do_reshape} argument as true.
+## 
+## Example:
+## @example
+## @group
+## base64encode('Hakuna Matata',true) 
+## ##returns 'SGFrdW5hIE1hdGF0YQ=='
+##
+## @end group
+## @end example
+## @seealso{base64decode}
+## @end deftypefn
+
+function Y = base64encode (X, do_reshape)
+
+  if (nargin < 1)
+    print_usage;
+  elseif nargin != 2
+    do_reshape=false;
+  endif
+  if (ischar(X))
+    X = toascii(X);
+  elseif (any(X(:)) != fix(X(:)) || any(X(:) < 0) || any(X(:) > 255))
+    error("base64encode is expecting integers in the range 0 .. 255");
+  endif
+
+  n = length(X(:));
+  X = X(:);
+
+  ## split the input into three pieces, zero padding to the same length
+  in1 = X(1:3:n);
+  in2 = zeros(size(in1));
+  in3 = zeros(size(in1));
+  in2(1:length(2:3:n)) = X(2:3:n);
+  in3(1:length(3:3:n)) = X(3:3:n);
+
+  ## put the top bits of the inputs into the bottom bits of the 
+  ## corresponding outputs
+  out1 = fix(in1/4);
+  out2 = fix(in2/16);
+  out3 = fix(in3/64);
+
+  ## add the bottom bits of the inputs as the top bits of the corresponding
+  ## outputs
+  out4 =            in3 - 64*out3;
+  out3 = out3 +  4*(in2 - 16*out2);
+  out2 = out2 + 16*(in1 -  4*out1);
+
+  ## correct the output for padding
+  if (length(2:3:n) < length(1:3:n)) out3(length(out3)) = 64; endif
+  if (length(3:3:n) < length(1:3:n)) out4(length(out4)) = 64; endif
+
+  ## 6-bit encoding table, plus 1 for padding
+  table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+
+  table([ out1']+ 1);
+  table([ out2']+ 1);
+  table([ out3']+ 1);
+  table([ out4']+ 1);
+
+  Y = table([ out1'; out2'; out3'; out4' ] + 1);
+
+  if ( do_reshape )
+     Y = reshape(Y,[1, prod(size(Y))]);
+  end
+endfunction
+
+%!assert(base64encode('Hakuna Matata',true),'SGFrdW5hIE1hdGF0YQ==')