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Unordered: Simpler erase implementation.

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[SVN r81207]
This commit is contained in:
Daniel James committed 2012-11-05 18:32:59 +00:00
1 parent 38d8d052d1
commit ccc3d1c83d
3 files changed
+104 -227
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include/boost/unordered/detail/equivalent.hpp
+49 -106
View File
@@ -545,9 +545,7 @@ namespace boost { namespace unordered { namespace detail {
std::size_t key_hash = this->hash(k);
std::size_t bucket_index =
policy::to_bucket(this->bucket_count_, key_hash);
bucket_pointer this_bucket = this->get_bucket(bucket_index);
link_pointer prev = this_bucket->next_;
link_pointer prev = this->get_previous_start(bucket_index);
if (!prev) return 0;
for (;;)
@@ -565,13 +563,12 @@ namespace boost { namespace unordered { namespace detail {
prev = static_cast<node_pointer>(prev->next_)->group_prev_;
}
node_pointer pos = static_cast<node_pointer>(prev->next_);
link_pointer end1 =
static_cast<node_pointer>(pos->group_prev_)->next_;
node_pointer end = static_cast<node_pointer>(end1);
prev->next_ = end1;
this->fix_buckets(this_bucket, prev, end);
return this->delete_nodes(c_iterator(pos), c_iterator(end));
node_pointer first_node = static_cast<node_pointer>(prev->next_);
link_pointer end = static_cast<node_pointer>(first_node->group_prev_)->next_;
std::size_t count = this->delete_nodes(prev, end);
this->fix_bucket(bucket_index, prev);
return count;
}
iterator erase(c_iterator r)
@@ -579,126 +576,72 @@ namespace boost { namespace unordered { namespace detail {
BOOST_ASSERT(r.node_);
iterator next(r.node_);
++next;
bucket_pointer this_bucket = this->get_bucket(
policy::to_bucket(this->bucket_count_, r.node_->hash_));
link_pointer prev = unlink_node(*this_bucket, r.node_);
this->fix_buckets(this_bucket, prev, next.node_);
this->delete_node(r);
erase_nodes(r.node_, next.node_);
return next;
}
iterator erase_range(c_iterator r1, c_iterator r2)
{
if (r1 == r2) return iterator(r2.node_);
std::size_t bucket_index =
policy::to_bucket(this->bucket_count_, r1.node_->hash_);
link_pointer prev = unlink_nodes(
*this->get_bucket(bucket_index), r1.node_, r2.node_);
this->fix_buckets_range(bucket_index, prev, r1.node_, r2.node_);
this->delete_nodes(r1, r2);
erase_nodes(r1.node_, r2.node_);
return iterator(r2.node_);
}
static link_pointer unlink_node(bucket& b, node_pointer n)
link_pointer erase_nodes(node_pointer begin, node_pointer end)
{
node_pointer next = static_cast<node_pointer>(n->next_);
link_pointer prev = n->group_prev_;
std::size_t bucket_index =
policy::to_bucket(this->bucket_count_, begin->hash_);
if(prev->next_ != n) {
// The node is at the beginning of a group.
// Split the groups containing 'begin' and 'end'.
// And get the pointer to the node before begin while
// we're at it.
link_pointer prev = split_groups(begin, end);
// Find the previous node pointer:
prev = b.next_;
while(prev->next_ != n) {
prev = static_cast<node_pointer>(prev->next_)->group_prev_;
}
// Remove from group
if (next && next->group_prev_ == n)
{
next->group_prev_ = n->group_prev_;
}
}
else if (next && next->group_prev_ == n)
{
// The deleted node is not at the end of the group, so
// change the link from the next node.
next->group_prev_ = n->group_prev_;
}
else {
// The deleted node is at the end of the group, so the
// first node in the group is pointing to it.
// Find that to change its pointer.
node_pointer x = static_cast<node_pointer>(n->group_prev_);
while (x->group_prev_ != n) {
x = static_cast<node_pointer>(x->group_prev_);
}
x->group_prev_ = n->group_prev_;
}
prev->next_ = next;
return prev;
}
static link_pointer unlink_nodes(bucket& b,
node_pointer begin, node_pointer end)
{
link_pointer prev = begin->group_prev_;
if (prev->next_ != begin) {
// The node is at the beginning of a group.
// Find the previous node pointer:
prev = b.next_;
// If we don't have a 'prev' it means that begin is at the
// beginning of a block, so search through the blocks in the
// same bucket.
if (!prev) {
prev = this->get_previous_start(bucket_index);
while (prev->next_ != begin)
prev = static_cast<node_pointer>(prev->next_)->group_prev_;
if (end) split_group(end);
}
else {
node_pointer group1 = split_group(begin);
if (end) {
node_pointer group2 = split_group(end);
if(begin == group2) {
link_pointer end1 = group1->group_prev_;
link_pointer end2 = end->group_prev_;
group1->group_prev_ = end2;
end->group_prev_ = end1;
}
}
}
prev->next_ = end;
// Delete the nodes.
do {
link_pointer group_end =
static_cast<node_pointer>(
static_cast<node_pointer>(prev->next_)->group_prev_)->next_;
this->delete_nodes(prev, group_end);
bucket_index = this->fix_bucket(bucket_index, prev);
} while(prev->next_ != end);
return prev;
}
// Break a ciruclar list into two, with split as the beginning
// of the second group (if split is at the beginning then don't
// split).
static node_pointer split_group(node_pointer split)
static link_pointer split_groups(node_pointer begin, node_pointer end)
{
// Find first node in group.
node_pointer first = split;
while (static_cast<node_pointer>(first->group_prev_)->next_ ==
first)
first = static_cast<node_pointer>(first->group_prev_);
node_pointer prev = static_cast<node_pointer>(begin->group_prev_);
if (prev->next_ != begin) prev = node_pointer();
if(first == split) return split;
if (end) {
node_pointer first = end;
while (first != begin && static_cast<node_pointer>(first->group_prev_)->next_ == first) {
first = static_cast<node_pointer>(first->group_prev_);
}
link_pointer last = first->group_prev_;
first->group_prev_ = split->group_prev_;
split->group_prev_ = last;
boost::swap(first->group_prev_, end->group_prev_);
if (first == begin) return prev;
}
return first;
if (prev) {
node_pointer first = prev;
while (static_cast<node_pointer>(first->group_prev_)->next_ == first) {
first = static_cast<node_pointer>(first->group_prev_);
}
boost::swap(first->group_prev_, begin->group_prev_);
}
return prev;
}
////////////////////////////////////////////////////////////////////////