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@xxxxxxxxxx>
---
fs/bcachefs/eytzinger.c | 42 ++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)
diff --git a/fs/bcachefs/eytzinger.c b/fs/bcachefs/eytzinger.c
index 93a5819a6878..00cc5f0826e3 100644
--- a/fs/bcachefs/eytzinger.c
+++ b/fs/bcachefs/eytzinger.c
@@ -170,7 +170,7 @@ 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)
@@ -186,46 +186,46 @@ 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);
}
}
}
--
2.48.1
