Mercurial > octave
view scripts/miscellaneous/swapbytes.m @ 32047:e3de59065cf1
inputParser.m: Re-architect internal data structures for 60% speed improvement.
Key idea is to replace Parameter and Switch structs with name field containing
a nested struct (def, val fields) with a struct array that has fields "name",
"def", and "val". This makes it possible to eliminate for loops.
* NEWS.9.md: Announce performance improvement.
* inputParser.m: Declare "Parameter" and "Switch" properties as struct arrays.
Add new private property "last_idx" which caches the last Parameter or Switch
lookup.
* inputParser.m (addRequired): Adjust input validation to use numel() now
rather than numfields().
* inputParser.m (addOptional): Adjust input validation to use numel() now
rather than numfields().
* inputParser.m (addParameter): Change code to add new Parameter to a struct
array.
* inputParser.m (addSwitch): Change code to add new Switch to a struct
array.
* inputParser.m (parse): Adjust initialization of internal variables
ParameterNames and SwitchNames to match new data structure.
Use last_idx to simplify call to validate_arg() for Parameters.
* inputParser.m (validate_arg): Move creation of error message
to code path when error has been found---No need to do it for every
function call. Don't capture "exception" variable in try/catch as
it is no longer used.
* inputParser.m (is_argname): Cache "last_idx" if match was found.
* inputParser.m (add_missing): Replace call to setdiff() with in-place
code which can take advantage of implicit knowledge to eliminate calls
to unique and input validation. Replace for loop with cell2struct/struct2cell
combination.
author | Rik <rik@octave.org> |
---|---|
date | Fri, 21 Apr 2023 11:01:40 -0700 |
parents | 597f3ee61a48 |
children | 2e484f9f1f18 |
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######################################################################## ## ## Copyright (C) 2007-2023 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 {} {@var{y} =} swapbytes (@var{x}) ## Swap the byte order on values, converting from little endian to big endian ## and vice versa. ## ## For example: ## ## @example ## @group ## swapbytes (uint16 (1:4)) ## @result{} 256 512 768 1024 ## @end group ## @end example ## ## @seealso{typecast, cast} ## @end deftypefn function y = swapbytes (x) if (nargin < 1) print_usage (); endif cls = class (x); if (strcmp (cls, "int8") || strcmp (cls, "uint8") || isempty (x)) y = x; else if (strcmp (cls, "int16") || strcmp (cls, "uint16")) nb = 2; elseif (strcmp (cls, "single") || strcmp (cls, "int32") || strcmp (cls, "uint32")) nb = 4; elseif (strcmp (cls, "double") || strcmp (cls, "int64") || strcmp (cls, "uint64")) nb = 8; else error ("swapbytes: invalid object of class '%s'", cls); endif y = reshape (typecast (reshape (typecast (x(:), "uint8"), nb, numel (x)) ([nb : -1 : 1], :) (:), cls), size (x)); endif endfunction %!assert (swapbytes (uint16 (1:4)), uint16 ([256 512 768 1024])) %!test %! assert (swapbytes (swapbytes (pi)), pi); %! assert (swapbytes (swapbytes (single (pi))), single (pi)); ## Test input validation %!error <Invalid call> swapbytes () %!error <invalid object of class 'cell'> swapbytes ({1})