Mercurial > hg > octave-max
changeset 10020:ffee051323f8
rewrite strjust
author | Jaroslav Hajek <highegg@gmail.com> |
---|---|
date | Thu, 24 Dec 2009 12:02:27 +0100 |
parents | 7ad32bf759c3 |
children | bf26f81d009f |
files | scripts/ChangeLog scripts/strings/strjust.m |
diffstat | 2 files changed, 42 insertions(+), 51 deletions(-) [+] |
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line diff
--- a/scripts/ChangeLog +++ b/scripts/ChangeLog @@ -1,3 +1,7 @@ +2009-12-24 Jaroslav Hajek <highegg@gmail.com> + + * strings/strjust.m: Rewrite. + 2009-12-23 Jaroslav Hajek <highegg@gmail.com> * strings/strjust.m: Special-case string and empty argument.
--- a/scripts/strings/strjust.m +++ b/scripts/strings/strjust.m @@ -1,4 +1,5 @@ ## Copyright (C) 2000, 2001, 2003, 2005, 2006, 2007, 2009 Paul Kienzle +## Copyright (C) 2009 Jaroslav Hajek ## ## This file is part of Octave. ## @@ -35,7 +36,7 @@ ## @end example ## @end deftypefn -function x = strjust (x, just) +function y = strjust (x, just) if (nargin < 1 || nargin > 2) print_usage (); @@ -52,59 +53,45 @@ endif if (isempty (x)) - return - endif + y = x; + else + ## Apparently, Matlab considers nulls to be blanks as well; however, does + ## not preserve the nulls, but rather converts them to blanks. That's a + ## bit unexpected, but it allows simpler processing, because we can move + ## just the nonblank characters. So we'll do the same here. + + [nr, nc] = size (x); + ## Find the indices of all nonblanks. + nonbl = x != " " & x != "\0"; + [idx, jdx] = find (nonbl); - if (rows (x) == 1) - ## string case - nonbl = x != " " & x != char (0); - n = length (x); - switch (just) - case "right" - idx = find (nonbl, 1, "last"); - if (idx < n) # false if idx is empty - x = [" "(1, ones (1, n-idx)), x(1:idx)]; - endif - case "left" - idx = find (nonbl, 1, "first"); - if (idx > 1) # false if idx is empty - x = [x(idx:n), " "(1, ones (1, idx))]; - endif - case "center" - idx = find (nonbl, 1, "first"); - jdx = find (nonbl, 1, "last"); - if (idx > 1 || jdx < n) - nsp = ((idx - 1) + (n - jdx)) / 2; - lpad = " "(1, ones (1, floor (nsp))); - rpad = " "(1, ones (1, ceil (nsp))); - x = [lpad, x(idx:jdx), rpad]; - endif - otherwise - error ("strjust: invalid justify type: %s", just); - endswitch - else - ## char matrix case. + if (strcmp (just, "right")) + ## We wish to find the maximum column index for each row. Because jdx is + ## sorted, we can take advantage of the fact that assignment is processed + ## sequentially and for duplicate indices the last value will remain. + maxs = nc * ones (nr, 1); + maxs(idx) = jdx; + shift = nc - maxs; + elseif (strcmp (just, "left")) + ## See above for explanation. + mins = ones (nr, 1); + mins(flipud (idx(:))) = flipud (jdx(:)); + shift = 1 - mins; + else + ## Use both of the above. + mins = ones (nr, 1); + mins(flipud (idx(:))) = flipud (jdx(:)); + maxs = nc * ones (nr, 1); + maxs(idx) = jdx; + shift = floor ((nc + 1 - maxs - mins) / 2); + endif - ## For all cases, left, right and center, the algorithm is the same. - ## Find the number of blanks at the left/right end to determine the - ## shift, rotate the row index by using mod with that shift, then - ## translate the shifted row index into an array index. - [nr, nc] = size (x); - idx = (x != " " & x != char (0)).'; - if (strcmp (just, "right")) - [N, hi] = max (cumsum (idx)); - shift = hi; - elseif (strcmp (just, "left")) - [N, lo] = max (cumsum (flipud (idx))); - shift = (nc - lo); - else - [N, hi] = max (cumsum (idx)); - [N, lo] = max (cumsum (flipud (idx))); - shift = ceil (nc - (lo-hi)/2); - endif - idx = rem (ones(nr,1)*[0:nc-1] + shift'*ones(1,nc), nc); - x = x (idx*nr + [1:nr]'*ones(1,nc)); + ## Adjust the column indices. + jdx += shift (idx); + ## Create a blank matrix and position the nonblank characters. + y = " "(ones (1, nr), ones (1, nc)); + y(sub2ind ([nr, nc], idx, jdx)) = x(nonbl); endif endfunction