dummy/linux-stable-mirror
1
0
Fork 1
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2025-04-19 20:58:31 +09:00
Code Issues Packages Projects Releases Wiki Activity

bcachefs: convert eytzinger sort to be 1-based (2)

Browse Source 
In this second step, transform the eytzinger indexes i, j, and k in
eytzinger1_sort_r() from 0-based to 1-based.  This step looks a bit
messy, but the resulting code is slightly better.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Andreas Gruenbacher 2025-01-27 20:54:52 +01:00 committed by Kent Overstreet
parent 3ff0dd28d6
commit 68eb4c5fea
1 changed files with 21 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
fs/bcachefs/eytzinger.c
View File

@ -171,7 +171,7 @@ static void eytzinger1_sort_r(void *base1, size_t n, size_t size,
swap_r_func_t swap_func,
const void *priv)
{
int i, j, k;
unsigned i, j, k;
/* called from 'sort' without swap function, let's pick the default */
if (swap_func == SWAP_WRAPPER && !((struct wrapper *)priv)->swap_func)
@ -187,46 +187,46 @@ static void eytzinger1_sort_r(void *base1, size_t n, size_t size,
}
/* heapify */
for (i = n / 2 - 1; i >= 0; --i) {
for (i = n / 2; i >= 1; --i) {
/* Find the sift-down path all the way to the leaves. */
for (j = i; k = j * 2 + 1, k + 1 < n;)
j = eytzinger1_do_cmp(base1, n, size, cmp_func, priv, k + 1, k + 2) > 0 ? k : k + 1;
for (j = i; k = j * 2, k < n;)
j = eytzinger1_do_cmp(base1, n, size, cmp_func, priv, k, k + 1) > 0 ? k : k + 1;
/* Special case for the last leaf with no sibling. */
if (j * 2 + 2 == n)
j = j * 2 + 1;
if (j * 2 == n)
j *= 2;
/* Backtrack to the correct location. */
while (j != i && eytzinger1_do_cmp(base1, n, size, cmp_func, priv, i + 1, j + 1) >= 0)
j = (j - 1) / 2;
while (j != i && eytzinger1_do_cmp(base1, n, size, cmp_func, priv, i, j) >= 0)
j /= 2;
/* Shift the element into its correct place. */
for (k = j; j != i;) {
j = (j - 1) / 2;
eytzinger1_do_swap(base1, n, size, swap_func, priv, j + 1, k + 1);
j /= 2;
eytzinger1_do_swap(base1, n, size, swap_func, priv, j, k);
}
}
/* sort */
for (i = n - 1; i > 0; --i) {
eytzinger1_do_swap(base1, n, size, swap_func, priv, 1, i + 1);
for (i = n; i > 1; --i) {
eytzinger1_do_swap(base1, n, size, swap_func, priv, 1, i);
/* Find the sift-down path all the way to the leaves. */
for (j = 0; k = j * 2 + 1, k + 1 < i;)
j = eytzinger1_do_cmp(base1, n, size, cmp_func, priv, k + 1, k + 2) > 0 ? k : k + 1;
for (j = 1; k = j * 2, k + 1 < i;)
j = eytzinger1_do_cmp(base1, n, size, cmp_func, priv, k, k + 1) > 0 ? k : k + 1;
/* Special case for the last leaf with no sibling. */
if (j * 2 + 2 == i)
j = j * 2 + 1;
if (j * 2 + 1 == i)
j *= 2;
/* Backtrack to the correct location. */
while (j && eytzinger1_do_cmp(base1, n, size, cmp_func, priv, 1, j + 1) >= 0)
j = (j - 1) / 2;
while (j >= 1 && eytzinger1_do_cmp(base1, n, size, cmp_func, priv, 1, j) >= 0)
j /= 2;
/* Shift the element into its correct place. */
for (k = j; j;) {
j = (j - 1) / 2;
eytzinger1_do_swap(base1, n, size, swap_func, priv, j + 1, k + 1);
for (k = j; j > 1;) {
j /= 2;
eytzinger1_do_swap(base1, n, size, swap_func, priv, j, k);
}
}
}