On 2014/07/03, at 2:06, Bram Moolenaar <b...@moolenaar.net> wrote:
> + static int item_compare_keep_zero;
This variable is set to FALSE for the sort() function, and only set to TRUE for
uniq(). Is this intentional?
Even if I set this variable to TRUE for sort(), the sort is still not stable
and test55 fails on my Mac:
--- test55.ok 2014-07-03 12:22:11.000000000 +0900
+++ test55.failed 2014-07-03 14:56:53.000000000 +0900
@@ -101,9 +101,9 @@
[[0, 1, 2], [0, 1, 2], 4, 2, 2, 1.5, 'xaaa', 'x8', 'foo6', 'foo', 'foo',
'A11', '-0']
['-0', 'A11', 'foo', 'foo', 'foo6', 'x8', 'xaaa', 1.5, 2, 2, 4, [0, 1, 2], [0,
1, 2]]
['-0', 'A11', 'foo', 'foo6', 'x8', 'xaaa', 1.5, 2, 4, [0, 1, 2]]
-[-1, 'one', 'two', 'three', 'four', 1.0e-15, 0.22, 7, 9, 12, 18, 22, 255]
-['bar', 'BAR', 'Bar', 'Foo', 'FOO', 'foo', 'FOOBAR', -1, 0, 0, 0.22, 1.0e-15,
12, 18, 22, 255, 7, 9, [], {}]
-['bar', 'BAR', 'Bar', 'Foo', 'FOO', 'foo', 'FOOBAR', -1, 0, 0, 0.22, 1.0e-15,
12, 18, 22, 255, 7, 9, [], {}]
+[-1, 'four', 'two', 'three', 'one', 1.0e-15, 0.22, 7, 9, 12, 18, 22, 255]
+['bar', 'Bar', 'BAR', 'FOO', 'foo', 'Foo', 'FOOBAR', -1, 0, 0, 0.22, 1.0e-15,
12, 18, 22, 255, 7, 9, [], {}]
+['bar', 'Bar', 'BAR', 'FOO', 'foo', 'Foo', 'FOOBAR', -1, 0, 0, 0.22, 1.0e-15,
12, 18, 22, 255, 7, 9, [], {}]
['BAR', 'Bar', 'FOO', 'FOOBAR', 'Foo', 'bar', 'foo', -1, 0, 0, 0.22, 1.0e-15,
12, 18, 22, 255, 7, 9, [], {}]
['aa', 'bb']
['aa', 'bb']
> + /* When the result would be zero, compare the pointers themselves.
> Makes
> + * the sort stable. */
> + if (res == 0 && !item_compare_keep_zero)
> + res = s1 > s2 ? 1 : -1;
> +
This doesn't work, it seems.
During the sort process the qsort() function swaps the data in the array ptrs[].
Comparing s1 and s2 is to compare the current position in the array,
which may have been already modified (swapped) by qsort().
I think we need to save the original position along with the data.
See the patch in my previous post (26 June, Re: Patch 7.4.341, the 4th post in
https://groups.google.com/forum/#!topic/vim_dev/RUByys6B3Yk). In this patch,
the original position is saved in the member 'i' of the struct sdata_T.
I think my patch works, but I guess it will make the sort somewhat slower,
because there are now two function calls per comparison. If this is a problem,
then we could modify item_compare() itself instead of using a wrapper function
item_compare_stable().
PS.
What is the best way of referring to a previous post in this mailing list?
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