diff scripts/strings/dec2base.m @ 3789:2a257be5e488

[project @ 2001-02-09 04:12:30 by jwe]
author jwe
date Fri, 09 Feb 2001 04:12:31 +0000
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+## Copyright (C) 2000 Daniel Calvelo
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2, or (at your option)
+## any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, write to the Free
+## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+## 02111-1307, USA.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} dec2base (@var{n}, @var{b})
+## Return a string of symbols in base @var{b} corresponding to the
+## the nonnegative integer @var{n}.
+##
+## @example
+## dec2base (123, 3)
+##      @result{} "11120"
+## @end example
+##
+## If @var{n} is a vector, return a string matrix with one row per value,
+## padded with leading zeros to the width of the largest value.
+##
+## If @var{b} is a string then the characters of @var{b} are used as
+## the symbols for the digits of @var{n}.  Space (' ') may not be used
+## as a symbol.
+##
+## @example
+## dec2base (123, "aei")
+##      @result{} "eeeia"
+## @end example
+## @end deftypefn
+##
+## @seealso{base2dec, dec2bin, bin2dec, hex2dec, dec2hex}
+
+## Author: Daniel Calvelo <>
+## Adapted-by: Paul Kienzle <pkienzle@kienzle.powernet.co.uk>
+
+function out = dec2base (d, base)
+
+  if (nargin != 2)
+    usage("dec2base (n, base)");
+  endif
+
+  if (prod (size (d)) != length (d))
+    error("dec2base: cannot convert matrices.");
+  elseif (any (d < 0 | d != fix (d)))
+    error("dec2base: can only convert non-negative integers.")
+  endif
+
+  symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+  if (isstr (base))
+    symbols = base;
+    base = length (symbols);
+    if any (diff (sort (toascii (symbols))) == 0)
+      error ("dec2base: symbols representing digits must be unique.");
+    endif
+  elseif (! is_scalar (base))
+    error ("dec2base: cannot convert from several bases at once.");
+  elseif (base < 2 || base > length (symbols))
+    error ("dec2base: base must be between 2 and 36 or a string of symbols");
+  endif
+  
+  ## determine number of digits required to handle all numbers
+  maxLen = floor (log (max (max (d), 1)) ./ log (base)) + 1;
+  
+  ## determine digits for each number
+  power = ones (length (d), 1) * (base .^ (maxLen-1 : -1 : 0));
+  d = d(:) * ones (1, maxLen);
+  digits = floor (rem (d, base*power) ./ power);
+
+  ## convert digits to symbols
+  out = reshape (symbols (digits+1), size (digits));
+
+endfunction