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Make g_array_sort* methods use a stable sort

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Also, remove previous comments about sort stability in g_array_sort docs,
as the method that was explained does not work. Adds a new comment
about this.

https://bugzilla.gnome.org/show_bug.cgi?id=672095
This commit is contained in:
Alexander Larsson 2012-03-14 21:17:47 +01:00
parent 839957f275
commit a43dd7435a
1 changed files with 23 additions and 19 deletions
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42
glib/garray.c
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@ -693,11 +693,7 @@ g_array_remove_range (GArray *farray,
* than second arg, zero for equal, greater zero if first arg is
* greater than second arg).
*
* If two array elements compare equal, their order in the sorted array
* is undefined. If you want equal elements to keep their order (i.e.
* you want a stable sort) you can write a comparison function that,
* if two elements would otherwise compare equal, compares them by
* their addresses.
* This is guaranteed to be a stable sort since version 2.32.
**/
void
g_array_sort (GArray *farray,
@ -707,10 +703,12 @@ g_array_sort (GArray *farray,
g_return_if_fail (array != NULL);
qsort (array->data,
array->len,
array->elt_size,
compare_func);
/* Don't use qsort as we want a guaranteed stable sort */
g_qsort_with_data (array->data,
array->len,
array->elt_size,
(GCompareDataFunc)compare_func,
NULL);
}
/**
@ -721,6 +719,12 @@ g_array_sort (GArray *farray,
*
* Like g_array_sort(), but the comparison function receives an extra
* user data argument.
*
* This is guaranteed to be a stable sort since version 2.32.
*
* There used to be a comment here about making the sort stable by
* using the addresses of the elements in the comparison function.
* This did not actually work, so any such code should be removed.
**/
void
g_array_sort_with_data (GArray *farray,
@ -1358,15 +1362,11 @@ g_ptr_array_add (GPtrArray *farray,
* than second arg, zero for equal, greater than zero if irst arg is
* greater than second arg).
*
* If two array elements compare equal, their order in the sorted array
* is undefined. If you want equal elements to keep their order (i.e.
* you want a stable sort) you can write a comparison function that,
* if two elements would otherwise compare equal, compares them by
* their addresses.
*
* <note><para>The comparison function for g_ptr_array_sort() doesn't
* take the pointers from the array as arguments, it takes pointers to
* the pointers in the array.</para></note>
*
* This is guaranteed to be a stable sort since version 2.32.
**/
void
g_ptr_array_sort (GPtrArray *array,
@ -1374,10 +1374,12 @@ g_ptr_array_sort (GPtrArray *array,
{
g_return_if_fail (array != NULL);
qsort (array->pdata,
array->len,
sizeof (gpointer),
compare_func);
/* Don't use qsort as we want a guaranteed stable sort */
g_qsort_with_data (array->pdata,
array->len,
sizeof (gpointer),
(GCompareDataFunc)compare_func,
NULL);
}
/**
@ -1392,6 +1394,8 @@ g_ptr_array_sort (GPtrArray *array,
* <note><para>The comparison function for g_ptr_array_sort_with_data()
* doesn't take the pointers from the array as arguments, it takes
* pointers to the pointers in the array.</para></note>
*
* This is guaranteed to be a stable sort since version 2.32.
**/
void
g_ptr_array_sort_with_data (GPtrArray *array,