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[btree] Implement btree::remove()

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This commit is contained in:
Ming-Hung Tsai
2020-06-04 16:31:24 +08:00
parent ef8e94b22c
commit e724a72045
3 changed files with 572 additions and 7 deletions
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108
persistent-data/data-structures/btree.tcc
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@@ -293,6 +293,23 @@ namespace persistent_data {
set_value(i, v);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::delete_at(unsigned i)
{
unsigned nr_entries = get_nr_entries();
if (i >= nr_entries)
throw runtime_error("key index out of bounds");
unsigned nr_to_copy = nr_entries - (i + 1);
if (nr_to_copy) {
::memmove(key_ptr(i), key_ptr(i + 1), sizeof(uint64_t) * nr_to_copy);
::memmove(value_ptr(i), value_ptr(i + 1), sizeof(typename ValueTraits::disk_type) * nr_to_copy);
}
set_nr_entries(nr_entries - 1);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::copy_entries(node_ref const &rhs,
@@ -309,6 +326,90 @@ namespace persistent_data {
set_nr_entries(n + count);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::move_entries(node_ref<ValueTraits> &rhs,
int count)
{
if (!count)
return;
unsigned nr_left = get_nr_entries();
unsigned nr_right = rhs.get_nr_entries();
unsigned max_entries = get_max_entries();
if (nr_left - count > max_entries || nr_right - count > max_entries)
throw runtime_error("too many entries");
if (count > 0) {
rhs.shift_entries_right(count);
copy_entries_to_right(rhs, count);
} else {
copy_entries_to_left(rhs, -count);
rhs.shift_entries_left(-count);
}
set_nr_entries(nr_left - count);
rhs.set_nr_entries(nr_right + count);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::copy_entries_to_left(node_ref const &rhs, unsigned count)
{
unsigned n = get_nr_entries();
if ((n + count) > get_max_entries())
throw runtime_error("too many entries");
::memcpy(key_ptr(n), rhs.key_ptr(0), sizeof(uint64_t) * count);
::memcpy(value_ptr(n), rhs.value_ptr(0), sizeof(typename ValueTraits::disk_type) * count);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::copy_entries_to_right(node_ref &rhs, unsigned count) const
{
unsigned n = rhs.get_nr_entries();
if ((n + count) > get_max_entries())
throw runtime_error("too many entries");
unsigned nr_left = get_nr_entries();
::memcpy(rhs.key_ptr(0), key_ptr(nr_left - count), sizeof(uint64_t) * count);
::memcpy(rhs.value_ptr(0), value_ptr(nr_left - count), sizeof(typename ValueTraits::disk_type) * count);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::shift_entries_left(unsigned shift)
{
unsigned n = get_nr_entries();
if (shift > n)
throw runtime_error("too many entries");
unsigned nr_shifted = n - shift;
::memmove(key_ptr(0), key_ptr(shift), sizeof(uint64_t) * nr_shifted);
::memmove(value_ptr(0), value_ptr(shift), sizeof(typename ValueTraits::disk_type) * nr_shifted);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::shift_entries_right(unsigned shift)
{
unsigned n = get_nr_entries();
if (n + shift > get_max_entries())
throw runtime_error("too many entries");
::memmove(key_ptr(shift), key_ptr(0), sizeof(uint64_t) * n);
::memmove(value_ptr(shift), value_ptr(0), sizeof(typename ValueTraits::disk_type) * n);
}
template <typename ValueTraits>
unsigned
node_ref<ValueTraits>::merge_threshold() const
{
return get_max_entries() / 3;
}
template <typename ValueTraits>
int
node_ref<ValueTraits>::bsearch(uint64_t key, int want_hi) const
@@ -601,13 +702,6 @@ namespace persistent_data {
return need_insert;
}
template <unsigned Levels, typename ValueTraits>
void
btree<Levels, ValueTraits>::remove(key const &key)
{
using namespace btree_detail;
}
template <unsigned Levels, typename ValueTraits>
block_address
btree<Levels, ValueTraits>::get_root() const