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prio_tree: cleanup prio_tree_left()/prio_tree_right()

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Introduce iter_walk_down()/iter_walk_up() to remove the common code
between prio_tree_left() and prio_tree_right().

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Xiao Guangrong 2012-03-23 15:02:15 -07:00 committed by Linus Torvalds
parent f42240d729
commit f35368dd1c
1 changed files with 37 additions and 41 deletions
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78
lib/prio_tree.c
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@ -304,6 +304,40 @@ void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node)
cur = prio_tree_replace(root, cur->parent, cur);
}
static void iter_walk_down(struct prio_tree_iter *iter)
{
iter->mask >>= 1;
if (iter->mask) {
if (iter->size_level)
iter->size_level++;
return;
}
if (iter->size_level) {
BUG_ON(!prio_tree_left_empty(iter->cur));
BUG_ON(!prio_tree_right_empty(iter->cur));
iter->size_level++;
iter->mask = ULONG_MAX;
} else {
iter->size_level = 1;
iter->mask = 1UL << (BITS_PER_LONG - 1);
}
}
static void iter_walk_up(struct prio_tree_iter *iter)
{
if (iter->mask == ULONG_MAX)
iter->mask = 1UL;
else if (iter->size_level == 1)
iter->mask = 1UL;
else
iter->mask <<= 1;
if (iter->size_level)
iter->size_level--;
if (!iter->size_level && (iter->value & iter->mask))
iter->value ^= iter->mask;
}
/*
* Following functions help to enumerate all prio_tree_nodes in the tree that
* overlap with the input interval X [radix_index, heap_index]. The enumeration
@ -322,21 +356,7 @@ static struct prio_tree_node *prio_tree_left(struct prio_tree_iter *iter,
if (iter->r_index <= *h_index) {
iter->cur = iter->cur->left;
iter->mask >>= 1;
if (iter->mask) {
if (iter->size_level)
iter->size_level++;
} else {
if (iter->size_level) {
BUG_ON(!prio_tree_left_empty(iter->cur));
BUG_ON(!prio_tree_right_empty(iter->cur));
iter->size_level++;
iter->mask = ULONG_MAX;
} else {
iter->size_level = 1;
iter->mask = 1UL << (BITS_PER_LONG - 1);
}
}
iter_walk_down(iter);
return iter->cur;
}
@ -363,22 +383,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter,
if (iter->r_index <= *h_index) {
iter->cur = iter->cur->right;
iter->mask >>= 1;
iter->value = value;
if (iter->mask) {
if (iter->size_level)
iter->size_level++;
} else {
if (iter->size_level) {
BUG_ON(!prio_tree_left_empty(iter->cur));
BUG_ON(!prio_tree_right_empty(iter->cur));
iter->size_level++;
iter->mask = ULONG_MAX;
} else {
iter->size_level = 1;
iter->mask = 1UL << (BITS_PER_LONG - 1);
}
}
iter_walk_down(iter);
return iter->cur;
}
@ -388,16 +393,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter,
static struct prio_tree_node *prio_tree_parent(struct prio_tree_iter *iter)
{
iter->cur = iter->cur->parent;
if (iter->mask == ULONG_MAX)
iter->mask = 1UL;
else if (iter->size_level == 1)
iter->mask = 1UL;
else
iter->mask <<= 1;
if (iter->size_level)
iter->size_level--;
if (!iter->size_level && (iter->value & iter->mask))
iter->value ^= iter->mask;
iter_walk_up(iter);
return iter->cur;
}