Mercurial > octave
view scripts/strings/dec2bin.m @ 28241:ef7bc64a604b
dec2bin.m: Fix algorithm for numbers less than intmin ('int32') (bug #58147).
* dec2bin.m: Document that negative numbers are restricted to < -flintmax/2.
Validate input and error if negative numbers greater than -flintmax/2 are
present. Update BIST tests.
author | Rik <rik@octave.org> |
---|---|
date | Sat, 25 Apr 2020 11:45:03 -0700 |
parents | ac3a078e688f |
children | 2bb050267d74 |
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######################################################################## ## ## Copyright (C) 1996-2020 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 3 of the License, 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, see ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {} dec2bin (@var{d}) ## @deftypefnx {} {} dec2bin (@var{d}, @var{len}) ## Return a string of ones and zeros representing the conversion of the integer ## @var{d} to a binary number. ## ## If @var{d} is negative, return the two's complement binary value of @var{d}. ## If @var{d} is a matrix or cell array, return a string matrix with one row ## for each element in @var{d}, padded with leading zeros to the width of the ## largest value. ## ## The optional second argument, @var{len}, specifies the minimum number of ## digits in the result. ## ## Examples: ## ## @example ## @group ## dec2bin (14) ## @result{} "1110" ## ## dec2bin (-14) ## @result{} "11110010" ## @end group ## @end example ## ## Programming Notes: The largest negative value that can be converted in to ## two's complement is @code{- (flintmax () / 2)}. ## ## @seealso{bin2dec, dec2base, dec2hex} ## @end deftypefn function b = dec2bin (d, len) if (nargin == 0 || nargin > 2) print_usage (); endif if (iscell (d)) d = cell2mat (d); endif ## Create column vector for algorithm (output is always col. vector anyways) d = d(:); lt_zero_idx = (d < 0); if (any (lt_zero_idx)) ## FIXME: Need an algorithm that works with larger values such as int64. if (any (d(lt_zero_idx) < -2^52)) error ("dec2bin: negative inputs cannot be less than -flintmax () / 2"); elseif (any (d(lt_zero_idx) < intmin ("int32"))) d(lt_zero_idx) += flintmax (); elseif (any (d < intmin ("int16"))) d(lt_zero_idx) += double (intmax ("uint32")) + 1; elseif (any (d < intmin ("int8"))) d(lt_zero_idx) += double (intmax ("uint16"))+ 1; else d(lt_zero_idx) += double (intmax ("uint8")) + 1; endif endif if (nargin == 1) b = dec2base (d, 2); else b = dec2base (d, 2, len); endif endfunction %!assert (dec2bin (3), "11") %!assert (dec2bin (14), "1110") %!assert (dec2bin (14, 6), "001110") %!assert (dec2bin ([1, 2; 3, 4]), ["001"; "011"; "010"; "100"]) %!assert (dec2bin ({1, 2; 3, 4}), ["001"; "011"; "010"; "100"]) %!assert (dec2bin ({1, 2; 3, 4}, 4), ["0001"; "0011"; "0010"; "0100"]) ## Test negative inputs %!assert (dec2bin (-3), "11111101") %!assert (dec2bin (-3, 3), "11111101") %!assert (dec2bin (-3, 9), "011111101") %!assert (dec2bin (-2^7 -1), "1111111101111111") %!assert (dec2bin (-2^15 -1), "11111111111111110111111111111111") ## FIXME: Matlab generates a string that is 64 characters long %!assert (dec2bin (-2^31 -1), %! "11111111111111111111101111111111111111111111111111111") %!assert (dec2bin (-2^52), %! "10000000000000000000000000000000000000000000000000000") ## FIXME: Uncomment when support for int64 is added %!#assert (dec2bin (-2^63), %! "1000000000000000000000000000000000000000000000000000000000000000") %!#test %! assert (dec2bin (int64 (-2^63)), %! "1000000000000000000000000000000000000000000000000000000000000000"); %!#test %! assert (dec2bin (int64 (-2^63) -1), %! "1000000000000000000000000000000000000000000000000000000000000000"); %!#test %! assert (dec2bin (int64 (-2^63) +1), %! "1000000000000000000000000000000000000000000000000000000000000001"); %!assert (dec2bin ([-1, -2; -3, -4]), %! ["11111111"; "11111101"; "11111110"; "11111100"]) %!assert (dec2bin ([1, 2; 3, -4]), %! ["00000001"; "00000011"; "00000010"; "11111100"]) %!assert (dec2bin ({1, 2; 3, -4}), %! ["00000001"; "00000011"; "00000010"; "11111100"]) ## Test input validation %!error dec2bin () %!error dec2bin (1, 2, 3) %!error <negative inputs cannot be less than> dec2bin (- flintmax ())