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Add _prev version of treap lookup and iteration

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_lookup() and _lookup_next() each had nearly identical loops that took a
dirty boolean.  We combine them into one walker with flags for dirty and
next and add a prev prev as well, giving us all the exported functions
with combinations of the flags.

We also add _last() to match _first() and _prev() to match _next().

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2017-01-09 14:34:14 -08:00
parent 2522509ec8
commit a45661e5b6
2 changed files with 87 additions and 39 deletions
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122
kmod/src/treap.c
View File

@@ -845,30 +845,46 @@ out:
return ret;
}
static void *treap_lookup(struct scoutfs_treap *treap, void *key, bool dirty)
enum {
LU_DIRTY,
LU_NEXT,
LU_PREV,
};
static void *treap_lookup(struct scoutfs_treap *treap, void *key, int flags)
{
struct treap_ref *ref = &treap->root_ref;
struct treap_node *parent = NULL;
struct treap_node *node = NULL;
struct treap_node *prev = NULL;
struct treap_node *next = NULL;
int cmp;
while (ref->gen) {
node = read_node(treap, parent, ref, dirty);
node = read_node(treap, parent, ref, flags & LU_DIRTY);
if (IS_ERR(node))
break;
cmp = treap->ops->compare(key, node->data);
if (cmp < 0)
if (cmp < 0) {
ref = &node->left;
else if (cmp > 0)
next = node;
} else if (cmp > 0) {
ref = &node->right;
else
prev = node;
} else {
break;
}
parent = node;
node = NULL;
}
if (!node && (flags & LU_PREV) && prev)
node = prev;
else if (!node && (flags & LU_NEXT) && next)
node = next;
if (IS_ERR(node))
return ERR_CAST(node);
if (node)
@@ -878,12 +894,32 @@ static void *treap_lookup(struct scoutfs_treap *treap, void *key, bool dirty)
void *scoutfs_treap_lookup(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, false);
return treap_lookup(treap, key, 0);
}
void *scoutfs_treap_lookup_dirty(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, true);
return treap_lookup(treap, key, LU_DIRTY);
}
void *scoutfs_treap_lookup_next(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, LU_NEXT);
}
void *scoutfs_treap_lookup_next_dirty(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, LU_NEXT | LU_DIRTY);
}
void *scoutfs_treap_lookup_prev(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, LU_PREV);
}
void *scoutfs_treap_lookup_prev_dirty(struct scoutfs_treap *treap, void *key)
{
return treap_lookup(treap, key, LU_PREV | LU_DIRTY);
}
void *scoutfs_treap_first(struct scoutfs_treap *treap)
@@ -908,6 +944,28 @@ void *scoutfs_treap_first(struct scoutfs_treap *treap)
return NULL;
}
void *scoutfs_treap_last(struct scoutfs_treap *treap)
{
struct treap_ref *ref = &treap->root_ref;
struct treap_node *parent = NULL;
struct treap_node *node = NULL;
while (ref->gen) {
node = read_node(treap, parent, ref, false);
if (IS_ERR(node))
break;
ref = &node->right;
parent = node;
}
if (IS_ERR(node))
return ERR_CAST(node);
if (node)
return node->data;
return NULL;
}
void *scoutfs_treap_next(struct scoutfs_treap *treap, void *data)
{
struct treap_node *node = container_of(data, struct treap_node, data);
@@ -939,51 +997,37 @@ out:
return NULL;
}
static void *lookup_next(struct scoutfs_treap *treap, void *key, bool dirty)
void *scoutfs_treap_prev(struct scoutfs_treap *treap, void *data)
{
struct treap_ref *ref = &treap->root_ref;
struct treap_node *parent = NULL;
struct treap_node *node = NULL;
struct treap_node *next = NULL;
int cmp;
struct treap_node *node = container_of(data, struct treap_node, data);
struct treap_node *parent;
while (ref->off) {
node = read_node(treap, parent, ref, dirty);
if (node->left.gen) {
node = read_node(treap, node, &node->left, false);
if (IS_ERR(node))
break;
goto out;
cmp = treap->ops->compare(key, node->data);
if (cmp < 0) {
ref = &node->left;
next = node;
} else if (cmp > 0) {
ref = &node->right;
} else {
next = node;
break;
while (node->right.gen) {
node = read_node(treap, node, &node->right, false);
if (IS_ERR(node))
goto out;
}
parent = node;
node = NULL;
goto out;
}
while (((parent = node->parent)) && node == parent->left.node)
node = parent;
node = parent;
out:
if (IS_ERR(node))
return ERR_CAST(node);
if (next)
return next->data;
if (node)
return node->data;
return NULL;
}
void *scoutfs_treap_lookup_next(struct scoutfs_treap *treap, void *key)
{
return lookup_next(treap, key, false);
}
void *scoutfs_treap_lookup_next_dirty(struct scoutfs_treap *treap, void *key)
{
return lookup_next(treap, key, true);
}
int scoutfs_treap_has_dirty(struct scoutfs_treap *treap)
{
return !!(treap->root_ref.aug_bits & SCOUTFS_TREAP_AUG_DIRTY);

4
kmod/src/treap.h
View File

@@ -29,9 +29,13 @@ void *scoutfs_treap_lookup(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_lookup_dirty(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_lookup_next(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_lookup_next_dirty(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_lookup_prev(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_lookup_prev_dirty(struct scoutfs_treap *treap, void *key);
void *scoutfs_treap_first(struct scoutfs_treap *treap);
void *scoutfs_treap_last(struct scoutfs_treap *treap);
void *scoutfs_treap_next(struct scoutfs_treap *treap, void *data);
void *scoutfs_treap_prev(struct scoutfs_treap *treap, void *data);
int scoutfs_treap_has_dirty(struct scoutfs_treap *treap);
int scoutfs_treap_dirty_ring(struct scoutfs_treap *treap);