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comparison scripts/strings/strjust.m @ 10020:ffee051323f8

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rewrite strjust
author Jaroslav Hajek <highegg@gmail.com>
date Thu, 24 Dec 2009 12:02:27 +0100
parents fb8834c12035
children d1978e7364ad
comparison
equal deleted inserted replaced
10019:7ad32bf759c3 10020:ffee051323f8
1 ## Copyright (C) 2000, 2001, 2003, 2005, 2006, 2007, 2009 Paul Kienzle 1 ## Copyright (C) 2000, 2001, 2003, 2005, 2006, 2007, 2009 Paul Kienzle
2 ## Copyright (C) 2009 Jaroslav Hajek
2 ## 3 ##
3 ## This file is part of Octave. 4 ## This file is part of Octave.
4 ## 5 ##
5 ## Octave is free software; you can redistribute it and/or modify it 6 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by 7 ## under the terms of the GNU General Public License as published by
33 ## abcd 34 ## abcd
34 ## @end group 35 ## @end group
35 ## @end example 36 ## @end example
36 ## @end deftypefn 37 ## @end deftypefn
37 38
38 function x = strjust (x, just) 39 function y = strjust (x, just)
39 40
40 if (nargin < 1 || nargin > 2) 41 if (nargin < 1 || nargin > 2)
41 print_usage (); 42 print_usage ();
42 endif 43 endif
43 44
50 if (ndims (x) != 2) 51 if (ndims (x) != 2)
51 error ("needs a string or character matrix"); 52 error ("needs a string or character matrix");
52 endif 53 endif
53 54
54 if (isempty (x)) 55 if (isempty (x))
55 return 56 y = x;
56 endif 57 else
58 ## Apparently, Matlab considers nulls to be blanks as well; however, does
59 ## not preserve the nulls, but rather converts them to blanks. That's a
60 ## bit unexpected, but it allows simpler processing, because we can move
61 ## just the nonblank characters. So we'll do the same here.
57 62
58 if (rows (x) == 1) 63 [nr, nc] = size (x);
59 ## string case 64 ## Find the indices of all nonblanks.
60 nonbl = x != " " & x != char (0); 65 nonbl = x != " " & x != "\0";
61 n = length (x); 66 [idx, jdx] = find (nonbl);
62 switch (just)
63 case "right"
64 idx = find (nonbl, 1, "last");
65 if (idx < n) # false if idx is empty
66 x = [" "(1, ones (1, n-idx)), x(1:idx)];
67 endif
68 case "left"
69 idx = find (nonbl, 1, "first");
70 if (idx > 1) # false if idx is empty
71 x = [x(idx:n), " "(1, ones (1, idx))];
72 endif
73 case "center"
74 idx = find (nonbl, 1, "first");
75 jdx = find (nonbl, 1, "last");
76 if (idx > 1 || jdx < n)
77 nsp = ((idx - 1) + (n - jdx)) / 2;
78 lpad = " "(1, ones (1, floor (nsp)));
79 rpad = " "(1, ones (1, ceil (nsp)));
80 x = [lpad, x(idx:jdx), rpad];
81 endif
82 otherwise
83 error ("strjust: invalid justify type: %s", just);
84 endswitch
85 else
86 ## char matrix case.
87 67
88 ## For all cases, left, right and center, the algorithm is the same.
89 ## Find the number of blanks at the left/right end to determine the
90 ## shift, rotate the row index by using mod with that shift, then
91 ## translate the shifted row index into an array index.
92 [nr, nc] = size (x);
93 idx = (x != " " & x != char (0)).';
94 if (strcmp (just, "right")) 68 if (strcmp (just, "right"))
95 [N, hi] = max (cumsum (idx)); 69 ## We wish to find the maximum column index for each row. Because jdx is
96 shift = hi; 70 ## sorted, we can take advantage of the fact that assignment is processed
71 ## sequentially and for duplicate indices the last value will remain.
72 maxs = nc * ones (nr, 1);
73 maxs(idx) = jdx;
74 shift = nc - maxs;
97 elseif (strcmp (just, "left")) 75 elseif (strcmp (just, "left"))
98 [N, lo] = max (cumsum (flipud (idx))); 76 ## See above for explanation.
99 shift = (nc - lo); 77 mins = ones (nr, 1);
78 mins(flipud (idx(:))) = flipud (jdx(:));
79 shift = 1 - mins;
100 else 80 else
101 [N, hi] = max (cumsum (idx)); 81 ## Use both of the above.
102 [N, lo] = max (cumsum (flipud (idx))); 82 mins = ones (nr, 1);
103 shift = ceil (nc - (lo-hi)/2); 83 mins(flipud (idx(:))) = flipud (jdx(:));
84 maxs = nc * ones (nr, 1);
85 maxs(idx) = jdx;
86 shift = floor ((nc + 1 - maxs - mins) / 2);
104 endif 87 endif
105 idx = rem (ones(nr,1)*[0:nc-1] + shift'*ones(1,nc), nc);
106 x = x (idx*nr + [1:nr]'*ones(1,nc));
107 88
89 ## Adjust the column indices.
90 jdx += shift (idx);
91
92 ## Create a blank matrix and position the nonblank characters.
93 y = " "(ones (1, nr), ones (1, nc));
94 y(sub2ind ([nr, nc], idx, jdx)) = x(nonbl);
108 endif 95 endif
109 96
110 endfunction 97 endfunction
111 98
112 %!error <Invalid call to strjust> strjust(); 99 %!error <Invalid call to strjust> strjust();