diff scripts/strings/base2dec.m @ 3789:2a257be5e488

[project @ 2001-02-09 04:12:30 by jwe]
author jwe
date Fri, 09 Feb 2001 04:12:31 +0000
parents
children c1c532a0acb2
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/strings/base2dec.m	Fri Feb 09 04:12:31 2001 +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} {} base2dec (@var{s}, @var{b})
+## Convert @var{s} from a string of digits of base @var{b} into an
+## integer.
+##
+## @example
+## base2dec ("11120", 3)
+##      @result{} 123
+## @end example
+##
+## If @var{s} is a matrix, returns a column vector with one value per
+## row of @var{s}.  If a row contains invalid symbols then the
+## corresponding value will be NaN.  Rows are right-justified before
+## converting so that trailing spaces are ignored.
+##
+## If @var{b} is a string, the characters of @var{b} are used as the
+## symbols for the digits of @var{s}. Space (' ') may not be used as a
+## symbol.
+##
+## @example
+## base2dec ("yyyzx", "xyz")
+##      @result{} 123
+## @end example
+##
+## @end deftypefn
+## @seealso{dec2base, dec2bin, bin2dec, hex2dec, dec2hex}
+
+## Author: Daniel Calvelo <>
+## Adapted-by: Paul Kienzle <pkienzle@kienzle.powernet.co.uk>
+
+function out = base2dec (d, base)
+
+  if (nargin != 2)
+    usage ("n = base2dec('d', base)");
+  endif
+
+  symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+  if (isstr (base))
+    symbols = base;
+    base = length (symbols);
+    if (any (diff (sort (toascii (symbols))) == 0))
+      error ("base2dec: symbols representing digits must be unique.");
+    endif
+  elseif (! is_scalar (base))
+    error ("base2dec: cannot convert from several bases at once.");
+  elseif (base < 2 || base > length (symbols))
+    error ("base2dec: base must be between 2 and 36 or a string of symbols");
+  else
+    d = toupper (d);
+  endif
+
+  ## Right justify the values before anything else.
+  d = strjust (d, "right");
+
+  ## Lookup value of symbols in symbol table, with invalid symbols
+  ## evaluating to NaN and space evaluating to 0.
+  table = NaN * ones (256, 1);
+  table (toascii (symbols (1 : base))) = 0 : base-1;
+  table (toascii (" ")) = 0;
+  d = reshape (table (toascii (d)), size (d));
+
+  ## Multiply the resulting digits by the appropriate power and
+  ## sum the rows.
+  out = d * (base .^ (columns(d)-1 : -1 : 0)');
+
+endfunction