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diff --git a/src/include/cpp-btree/btree.h b/src/include/cpp-btree/btree.h new file mode 100644 index 00000000..0a40e0e1 --- /dev/null +++ b/src/include/cpp-btree/btree.h @@ -0,0 +1,2396 @@ +// Copyright 2013 Google Inc. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// A btree implementation of the STL set and map interfaces. A btree is both +// smaller and faster than STL set/map. The red-black tree implementation of +// STL set/map has an overhead of 3 pointers (left, right and parent) plus the +// node color information for each stored value. So a set<int32> consumes 20 +// bytes for each value stored. This btree implementation stores multiple +// values on fixed size nodes (usually 256 bytes) and doesn't store child +// pointers for leaf nodes. The result is that a btree_set<int32> may use much +// less memory per stored value. For the random insertion benchmark in +// btree_test.cc, a btree_set<int32> with node-size of 256 uses 4.9 bytes per +// stored value. +// +// The packing of multiple values on to each node of a btree has another effect +// besides better space utilization: better cache locality due to fewer cache +// lines being accessed. Better cache locality translates into faster +// operations. +// +// CAVEATS +// +// Insertions and deletions on a btree can cause splitting, merging or +// rebalancing of btree nodes. And even without these operations, insertions +// and deletions on a btree will move values around within a node. In both +// cases, the result is that insertions and deletions can invalidate iterators +// pointing to values other than the one being inserted/deleted. This is +// notably different from STL set/map which takes care to not invalidate +// iterators on insert/erase except, of course, for iterators pointing to the +// value being erased. A partial workaround when erasing is available: +// erase() returns an iterator pointing to the item just after the one that was +// erased (or end() if none exists). See also safe_btree. + +// PERFORMANCE +// +// btree_bench --benchmarks=. 2>&1 | ./benchmarks.awk +// +// Run on pmattis-warp.nyc (4 X 2200 MHz CPUs); 2010/03/04-15:23:06 +// Benchmark STL(ns) B-Tree(ns) @ <size> +// -------------------------------------------------------- +// BM_set_int32_insert 1516 608 +59.89% <256> [40.0, 5.2] +// BM_set_int32_lookup 1160 414 +64.31% <256> [40.0, 5.2] +// BM_set_int32_fulllookup 960 410 +57.29% <256> [40.0, 4.4] +// BM_set_int32_delete 1741 528 +69.67% <256> [40.0, 5.2] +// BM_set_int32_queueaddrem 3078 1046 +66.02% <256> [40.0, 5.5] +// BM_set_int32_mixedaddrem 3600 1384 +61.56% <256> [40.0, 5.3] +// BM_set_int32_fifo 227 113 +50.22% <256> [40.0, 4.4] +// BM_set_int32_fwditer 158 26 +83.54% <256> [40.0, 5.2] +// BM_map_int32_insert 1551 636 +58.99% <256> [48.0, 10.5] +// BM_map_int32_lookup 1200 508 +57.67% <256> [48.0, 10.5] +// BM_map_int32_fulllookup 989 487 +50.76% <256> [48.0, 8.8] +// BM_map_int32_delete 1794 628 +64.99% <256> [48.0, 10.5] +// BM_map_int32_queueaddrem 3189 1266 +60.30% <256> [48.0, 11.6] +// BM_map_int32_mixedaddrem 3822 1623 +57.54% <256> [48.0, 10.9] +// BM_map_int32_fifo 151 134 +11.26% <256> [48.0, 8.8] +// BM_map_int32_fwditer 161 32 +80.12% <256> [48.0, 10.5] +// BM_set_int64_insert 1546 636 +58.86% <256> [40.0, 10.5] +// BM_set_int64_lookup 1200 512 +57.33% <256> [40.0, 10.5] +// BM_set_int64_fulllookup 971 487 +49.85% <256> [40.0, 8.8] +// BM_set_int64_delete 1745 616 +64.70% <256> [40.0, 10.5] +// BM_set_int64_queueaddrem 3163 1195 +62.22% <256> [40.0, 11.6] +// BM_set_int64_mixedaddrem 3760 1564 +58.40% <256> [40.0, 10.9] +// BM_set_int64_fifo 146 103 +29.45% <256> [40.0, 8.8] +// BM_set_int64_fwditer 162 31 +80.86% <256> [40.0, 10.5] +// BM_map_int64_insert 1551 720 +53.58% <256> [48.0, 20.7] +// BM_map_int64_lookup 1214 612 +49.59% <256> [48.0, 20.7] +// BM_map_int64_fulllookup 994 592 +40.44% <256> [48.0, 17.2] +// BM_map_int64_delete 1778 764 +57.03% <256> [48.0, 20.7] +// BM_map_int64_queueaddrem 3189 1547 +51.49% <256> [48.0, 20.9] +// BM_map_int64_mixedaddrem 3779 1887 +50.07% <256> [48.0, 21.6] +// BM_map_int64_fifo 147 145 +1.36% <256> [48.0, 17.2] +// BM_map_int64_fwditer 162 41 +74.69% <256> [48.0, 20.7] +// BM_set_string_insert 1989 1966 +1.16% <256> [64.0, 44.5] +// BM_set_string_lookup 1709 1600 +6.38% <256> [64.0, 44.5] +// BM_set_string_fulllookup 1573 1529 +2.80% <256> [64.0, 35.4] +// BM_set_string_delete 2520 1920 +23.81% <256> [64.0, 44.5] +// BM_set_string_queueaddrem 4706 4309 +8.44% <256> [64.0, 48.3] +// BM_set_string_mixedaddrem 5080 4654 +8.39% <256> [64.0, 46.7] +// BM_set_string_fifo 318 512 -61.01% <256> [64.0, 35.4] +// BM_set_string_fwditer 182 93 +48.90% <256> [64.0, 44.5] +// BM_map_string_insert 2600 2227 +14.35% <256> [72.0, 55.8] +// BM_map_string_lookup 2068 1730 +16.34% <256> [72.0, 55.8] +// BM_map_string_fulllookup 1859 1618 +12.96% <256> [72.0, 44.0] +// BM_map_string_delete 3168 2080 +34.34% <256> [72.0, 55.8] +// BM_map_string_queueaddrem 5840 4701 +19.50% <256> [72.0, 59.4] +// BM_map_string_mixedaddrem 6400 5200 +18.75% <256> [72.0, 57.8] +// BM_map_string_fifo 398 596 -49.75% <256> [72.0, 44.0] +// BM_map_string_fwditer 243 113 +53.50% <256> [72.0, 55.8] + +#ifndef UTIL_BTREE_BTREE_H__ +#define UTIL_BTREE_BTREE_H__ + +#include <stddef.h> +#include <string.h> +#include <sys/types.h> +#include <algorithm> +#include <functional> +#include <iostream> +#include <iterator> +#include <limits> +#include <type_traits> +#include <new> +#include <ostream> +#include <string> +#include <utility> + +#include "include/ceph_assert.h" + +namespace btree { + +// Inside a btree method, if we just call swap(), it will choose the +// btree::swap method, which we don't want. And we can't say ::swap +// because then MSVC won't pickup any std::swap() implementations. We +// can't just use std::swap() directly because then we don't get the +// specialization for types outside the std namespace. So the solution +// is to have a special swap helper function whose name doesn't +// collide with other swap functions defined by the btree classes. +template <typename T> +inline void btree_swap_helper(T &a, T &b) { + using std::swap; + swap(a, b); +} + +// A template helper used to select A or B based on a condition. +template<bool cond, typename A, typename B> +struct if_{ + typedef A type; +}; + +template<typename A, typename B> +struct if_<false, A, B> { + typedef B type; +}; + +// Types small_ and big_ are promise that sizeof(small_) < sizeof(big_) +typedef char small_; + +struct big_ { + char dummy[2]; +}; + +// A compile-time assertion. +template <bool> +struct CompileAssert { +}; + +#define COMPILE_ASSERT(expr, msg) \ + typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1] + +// A helper type used to indicate that a key-compare-to functor has been +// provided. A user can specify a key-compare-to functor by doing: +// +// struct MyStringComparer +// : public util::btree::btree_key_compare_to_tag { +// int operator()(const string &a, const string &b) const { +// return a.compare(b); +// } +// }; +// +// Note that the return type is an int and not a bool. There is a +// COMPILE_ASSERT which enforces this return type. +struct btree_key_compare_to_tag { +}; + +// A helper class that indicates if the Compare parameter is derived from +// btree_key_compare_to_tag. +template <typename Compare> +struct btree_is_key_compare_to + : public std::is_convertible<Compare, btree_key_compare_to_tag> { +}; + +// A helper class to convert a boolean comparison into a three-way +// "compare-to" comparison that returns a negative value to indicate +// less-than, zero to indicate equality and a positive value to +// indicate greater-than. This helper class is specialized for +// less<string> and greater<string>. The btree_key_compare_to_adapter +// class is provided so that btree users automatically get the more +// efficient compare-to code when using common google string types +// with common comparison functors. +template <typename Compare> +struct btree_key_compare_to_adapter : Compare { + btree_key_compare_to_adapter() { } + btree_key_compare_to_adapter(const Compare &c) : Compare(c) { } + btree_key_compare_to_adapter(const btree_key_compare_to_adapter<Compare> &c) + : Compare(c) { + } +}; + +template <> +struct btree_key_compare_to_adapter<std::less<std::string> > + : public btree_key_compare_to_tag { + btree_key_compare_to_adapter() {} + btree_key_compare_to_adapter(const std::less<std::string>&) {} + btree_key_compare_to_adapter( + const btree_key_compare_to_adapter<std::less<std::string> >&) {} + int operator()(const std::string &a, const std::string &b) const { + return a.compare(b); + } +}; + +template <> +struct btree_key_compare_to_adapter<std::greater<std::string> > + : public btree_key_compare_to_tag { + btree_key_compare_to_adapter() {} + btree_key_compare_to_adapter(const std::greater<std::string>&) {} + btree_key_compare_to_adapter( + const btree_key_compare_to_adapter<std::greater<std::string> >&) {} + int operator()(const std::string &a, const std::string &b) const { + return b.compare(a); + } +}; + +// A helper class that allows a compare-to functor to behave like a plain +// compare functor. This specialization is used when we do not have a +// compare-to functor. +template <typename Key, typename Compare, bool HaveCompareTo> +struct btree_key_comparer { + btree_key_comparer() {} + btree_key_comparer(Compare c) : comp(c) {} + static bool bool_compare(const Compare &comp, const Key &x, const Key &y) { + return comp(x, y); + } + bool operator()(const Key &x, const Key &y) const { + return bool_compare(comp, x, y); + } + Compare comp; +}; + +// A specialization of btree_key_comparer when a compare-to functor is +// present. We need a plain (boolean) comparison in some parts of the btree +// code, such as insert-with-hint. +template <typename Key, typename Compare> +struct btree_key_comparer<Key, Compare, true> { + btree_key_comparer() {} + btree_key_comparer(Compare c) : comp(c) {} + static bool bool_compare(const Compare &comp, const Key &x, const Key &y) { + return comp(x, y) < 0; + } + bool operator()(const Key &x, const Key &y) const { + return bool_compare(comp, x, y); + } + Compare comp; +}; + +// A helper function to compare to keys using the specified compare +// functor. This dispatches to the appropriate btree_key_comparer comparison, +// depending on whether we have a compare-to functor or not (which depends on +// whether Compare is derived from btree_key_compare_to_tag). +template <typename Key, typename Compare> +static bool btree_compare_keys( + const Compare &comp, const Key &x, const Key &y) { + typedef btree_key_comparer<Key, Compare, + btree_is_key_compare_to<Compare>::value> key_comparer; + return key_comparer::bool_compare(comp, x, y); +} + +template <typename Key, typename Compare, + typename Alloc, int TargetNodeSize, int ValueSize> +struct btree_common_params { + // If Compare is derived from btree_key_compare_to_tag then use it as the + // key_compare type. Otherwise, use btree_key_compare_to_adapter<> which will + // fall-back to Compare if we don't have an appropriate specialization. + typedef typename if_< + btree_is_key_compare_to<Compare>::value, + Compare, btree_key_compare_to_adapter<Compare> >::type key_compare; + // A type which indicates if we have a key-compare-to functor or a plain old + // key-compare functor. + typedef btree_is_key_compare_to<key_compare> is_key_compare_to; + + typedef Alloc allocator_type; + typedef Key key_type; + typedef ssize_t size_type; + typedef ptrdiff_t difference_type; + + enum { + kTargetNodeSize = TargetNodeSize, + + // Available space for values. This is largest for leaf nodes, + // which has overhead no fewer than two pointers. + kNodeValueSpace = TargetNodeSize - 2 * sizeof(void*), + }; + + // This is an integral type large enough to hold as many + // ValueSize-values as will fit a node of TargetNodeSize bytes. + typedef typename if_< + (kNodeValueSpace / ValueSize) >= 256, + uint16_t, + uint8_t>::type node_count_type; +}; + +// A parameters structure for holding the type parameters for a btree_map. +template <typename Key, typename Data, typename Compare, + typename Alloc, int TargetNodeSize> +struct btree_map_params + : public btree_common_params<Key, Compare, Alloc, TargetNodeSize, + sizeof(Key) + sizeof(Data)> { + typedef Data data_type; + typedef Data mapped_type; + typedef std::pair<const Key, data_type> value_type; + typedef std::pair<Key, data_type> mutable_value_type; + typedef value_type* pointer; + typedef const value_type* const_pointer; + typedef value_type& reference; + typedef const value_type& const_reference; + + enum { + kValueSize = sizeof(Key) + sizeof(data_type), + }; + + static const Key& key(const value_type &x) { return x.first; } + static const Key& key(const mutable_value_type &x) { return x.first; } + static void swap(mutable_value_type *a, mutable_value_type *b) { + btree_swap_helper(a->first, b->first); + btree_swap_helper(a->second, b->second); + } +}; + +// A parameters structure for holding the type parameters for a btree_set. +template <typename Key, typename Compare, typename Alloc, int TargetNodeSize> +struct btree_set_params + : public btree_common_params<Key, Compare, Alloc, TargetNodeSize, + sizeof(Key)> { + typedef std::false_type data_type; + typedef std::false_type mapped_type; + typedef Key value_type; + typedef value_type mutable_value_type; + typedef value_type* pointer; + typedef const value_type* const_pointer; + typedef value_type& reference; + typedef const value_type& const_reference; + + enum { + kValueSize = sizeof(Key), + }; + + static const Key& key(const value_type &x) { return x; } + static void swap(mutable_value_type *a, mutable_value_type *b) { + btree_swap_helper<mutable_value_type>(*a, *b); + } +}; + +// An adapter class that converts a lower-bound compare into an upper-bound +// compare. +template <typename Key, typename Compare> +struct btree_upper_bound_adapter : public Compare { + btree_upper_bound_adapter(Compare c) : Compare(c) {} + bool operator()(const Key &a, const Key &b) const { + return !static_cast<const Compare&>(*this)(b, a); + } +}; + +template <typename Key, typename CompareTo> +struct btree_upper_bound_compare_to_adapter : public CompareTo { + btree_upper_bound_compare_to_adapter(CompareTo c) : CompareTo(c) {} + int operator()(const Key &a, const Key &b) const { + return static_cast<const CompareTo&>(*this)(b, a); + } +}; + +// Dispatch helper class for using linear search with plain compare. +template <typename K, typename N, typename Compare> +struct btree_linear_search_plain_compare { + static int lower_bound(const K &k, const N &n, Compare comp) { + return n.linear_search_plain_compare(k, 0, n.count(), comp); + } + static int upper_bound(const K &k, const N &n, Compare comp) { + typedef btree_upper_bound_adapter<K, Compare> upper_compare; + return n.linear_search_plain_compare(k, 0, n.count(), upper_compare(comp)); + } +}; + +// Dispatch helper class for using linear search with compare-to +template <typename K, typename N, typename CompareTo> +struct btree_linear_search_compare_to { + static int lower_bound(const K &k, const N &n, CompareTo comp) { + return n.linear_search_compare_to(k, 0, n.count(), comp); + } + static int upper_bound(const K &k, const N &n, CompareTo comp) { + typedef btree_upper_bound_adapter<K, + btree_key_comparer<K, CompareTo, true> > upper_compare; + return n.linear_search_plain_compare(k, 0, n.count(), upper_compare(comp)); + } +}; + +// Dispatch helper class for using binary search with plain compare. +template <typename K, typename N, typename Compare> +struct btree_binary_search_plain_compare { + static int lower_bound(const K &k, const N &n, Compare comp) { + return n.binary_search_plain_compare(k, 0, n.count(), comp); + } + static int upper_bound(const K &k, const N &n, Compare comp) { + typedef btree_upper_bound_adapter<K, Compare> upper_compare; + return n.binary_search_plain_compare(k, 0, n.count(), upper_compare(comp)); + } +}; + +// Dispatch helper class for using binary search with compare-to. +template <typename K, typename N, typename CompareTo> +struct btree_binary_search_compare_to { + static int lower_bound(const K &k, const N &n, CompareTo comp) { + return n.binary_search_compare_to(k, 0, n.count(), CompareTo()); + } + static int upper_bound(const K &k, const N &n, CompareTo comp) { + typedef btree_upper_bound_adapter<K, + btree_key_comparer<K, CompareTo, true> > upper_compare; + return n.linear_search_plain_compare(k, 0, n.count(), upper_compare(comp)); + } +}; + +// A node in the btree holding. The same node type is used for both internal +// and leaf nodes in the btree, though the nodes are allocated in such a way +// that the children array is only valid in internal nodes. +template <typename Params> +class btree_node { + public: + typedef Params params_type; + typedef btree_node<Params> self_type; + typedef typename Params::key_type key_type; + typedef typename Params::data_type data_type; + typedef typename Params::value_type value_type; + typedef typename Params::mutable_value_type mutable_value_type; + typedef typename Params::pointer pointer; + typedef typename Params::const_pointer const_pointer; + typedef typename Params::reference reference; + typedef typename Params::const_reference const_reference; + typedef typename Params::key_compare key_compare; + typedef typename Params::size_type size_type; + typedef typename Params::difference_type difference_type; + // Typedefs for the various types of node searches. + typedef btree_linear_search_plain_compare< + key_type, self_type, key_compare> linear_search_plain_compare_type; + typedef btree_linear_search_compare_to< + key_type, self_type, key_compare> linear_search_compare_to_type; + typedef btree_binary_search_plain_compare< + key_type, self_type, key_compare> binary_search_plain_compare_type; + typedef btree_binary_search_compare_to< + key_type, self_type, key_compare> binary_search_compare_to_type; + // If we have a valid key-compare-to type, use linear_search_compare_to, + // otherwise use linear_search_plain_compare. + typedef typename if_< + Params::is_key_compare_to::value, + linear_search_compare_to_type, + linear_search_plain_compare_type>::type linear_search_type; + // If we have a valid key-compare-to type, use binary_search_compare_to, + // otherwise use binary_search_plain_compare. + typedef typename if_< + Params::is_key_compare_to::value, + binary_search_compare_to_type, + binary_search_plain_compare_type>::type binary_search_type; + // If the key is an integral or floating point type, use linear search which + // is faster than binary search for such types. Might be wise to also + // configure linear search based on node-size. + typedef typename if_< + std::is_integral<key_type>::value || + std::is_floating_point<key_type>::value, + linear_search_type, binary_search_type>::type search_type; + + struct base_fields { + typedef typename Params::node_count_type field_type; + + // A boolean indicating whether the node is a leaf or not. + bool leaf; + // The position of the node in the node's parent. + field_type position; + // The maximum number of values the node can hold. + field_type max_count; + // The count of the number of values in the node. + field_type count; + // A pointer to the node's parent. + btree_node *parent; + }; + + enum { + kValueSize = params_type::kValueSize, + kTargetNodeSize = params_type::kTargetNodeSize, + + // Compute how many values we can fit onto a leaf node. + kNodeTargetValues = (kTargetNodeSize - sizeof(base_fields)) / kValueSize, + // We need a minimum of 3 values per internal node in order to perform + // splitting (1 value for the two nodes involved in the split and 1 value + // propagated to the parent as the delimiter for the split). + kNodeValues = kNodeTargetValues >= 3 ? kNodeTargetValues : 3, + + kExactMatch = 1 << 30, + kMatchMask = kExactMatch - 1, + }; + + struct leaf_fields : public base_fields { + // The array of values. Only the first count of these values have been + // constructed and are valid. + mutable_value_type values[kNodeValues]; + }; + + struct internal_fields : public leaf_fields { + // The array of child pointers. The keys in children_[i] are all less than + // key(i). The keys in children_[i + 1] are all greater than key(i). There + // are always count + 1 children. + btree_node *children[kNodeValues + 1]; + }; + + struct root_fields : public internal_fields { + btree_node *rightmost; + size_type size; + }; + + public: + // Getter/setter for whether this is a leaf node or not. This value doesn't + // change after the node is created. + bool leaf() const { return fields_.leaf; } + + // Getter for the position of this node in its parent. + int position() const { return fields_.position; } + void set_position(int v) { fields_.position = v; } + + // Getter/setter for the number of values stored in this node. + int count() const { return fields_.count; } + void set_count(int v) { fields_.count = v; } + int max_count() const { return fields_.max_count; } + + // Getter for the parent of this node. + btree_node* parent() const { return fields_.parent; } + // Getter for whether the node is the root of the tree. The parent of the + // root of the tree is the leftmost node in the tree which is guaranteed to + // be a leaf. + bool is_root() const { return parent()->leaf(); } + void make_root() { + ceph_assert(parent()->is_root()); + fields_.parent = fields_.parent->parent(); + } + + // Getter for the rightmost root node field. Only valid on the root node. + btree_node* rightmost() const { return fields_.rightmost; } + btree_node** mutable_rightmost() { return &fields_.rightmost; } + + // Getter for the size root node field. Only valid on the root node. + size_type size() const { return fields_.size; } + size_type* mutable_size() { return &fields_.size; } + + // Getters for the key/value at position i in the node. + const key_type& key(int i) const { + return params_type::key(fields_.values[i]); + } + reference value(int i) { + return reinterpret_cast<reference>(fields_.values[i]); + } + const_reference value(int i) const { + return reinterpret_cast<const_reference>(fields_.values[i]); + } + mutable_value_type* mutable_value(int i) { + return &fields_.values[i]; + } + + // Swap value i in this node with value j in node x. + void value_swap(int i, btree_node *x, int j) { + params_type::swap(mutable_value(i), x->mutable_value(j)); + } + + // Getters/setter for the child at position i in the node. + btree_node* child(int i) const { return fields_.children[i]; } + btree_node** mutable_child(int i) { return &fields_.children[i]; } + void set_child(int i, btree_node *c) { + *mutable_child(i) = c; + c->fields_.parent = this; + c->fields_.position = i; + } + + // Returns the position of the first value whose key is not less than k. + template <typename Compare> + int lower_bound(const key_type &k, const Compare &comp) const { + return search_type::lower_bound(k, *this, comp); + } + // Returns the position of the first value whose key is greater than k. + template <typename Compare> + int upper_bound(const key_type &k, const Compare &comp) const { + return search_type::upper_bound(k, *this, comp); + } + + // Returns the position of the first value whose key is not less than k using + // linear search performed using plain compare. + template <typename Compare> + int linear_search_plain_compare( + const key_type &k, int s, int e, const Compare &comp) const { + while (s < e) { + if (!btree_compare_keys(comp, key(s), k)) { + break; + } + ++s; + } + return s; + } + + // Returns the position of the first value whose key is not less than k using + // linear search performed using compare-to. + template <typename Compare> + int linear_search_compare_to( + const key_type &k, int s, int e, const Compare &comp) const { + while (s < e) { + int c = comp(key(s), k); + if (c == 0) { + return s | kExactMatch; + } else if (c > 0) { + break; + } + ++s; + } + return s; + } + + // Returns the position of the first value whose key is not less than k using + // binary search performed using plain compare. + template <typename Compare> + int binary_search_plain_compare( + const key_type &k, int s, int e, const Compare &comp) const { + while (s != e) { + int mid = (s + e) / 2; + if (btree_compare_keys(comp, key(mid), k)) { + s = mid + 1; + } else { + e = mid; + } + } + return s; + } + + // Returns the position of the first value whose key is not less than k using + // binary search performed using compare-to. + template <typename CompareTo> + int binary_search_compare_to( + const key_type &k, int s, int e, const CompareTo &comp) const { + while (s != e) { + int mid = (s + e) / 2; + int c = comp(key(mid), k); + if (c < 0) { + s = mid + 1; + } else if (c > 0) { + e = mid; + } else { + // Need to return the first value whose key is not less than k, which + // requires continuing the binary search. Note that we are guaranteed + // that the result is an exact match because if "key(mid-1) < k" the + // call to binary_search_compare_to() will return "mid". + s = binary_search_compare_to(k, s, mid, comp); + return s | kExactMatch; + } + } + return s; + } + + // Inserts the value x at position i, shifting all existing values and + // children at positions >= i to the right by 1. + void insert_value(int i, const value_type &x); + + // Removes the value at position i, shifting all existing values and children + // at positions > i to the left by 1. + void remove_value(int i); + + // Rebalances a node with its right sibling. + void rebalance_right_to_left(btree_node *sibling, int to_move); + void rebalance_left_to_right(btree_node *sibling, int to_move); + + // Splits a node, moving a portion of the node's values to its right sibling. + void split(btree_node *sibling, int insert_position); + + // Merges a node with its right sibling, moving all of the values and the + // delimiting key in the parent node onto itself. + void merge(btree_node *sibling); + + // Swap the contents of "this" and "src". + void swap(btree_node *src); + +#ifdef NDEBUG + static constexpr auto no_debug = true; +#else + static constexpr auto no_debug = false; +#endif + // Node allocation/deletion routines. + static btree_node* init_leaf( + leaf_fields *f, btree_node *parent, int max_count) { + btree_node *n = reinterpret_cast<btree_node*>(f); + f->leaf = 1; + f->position = 0; + f->max_count = max_count; + f->count = 0; + f->parent = parent; + if (!no_debug) { + memset(&f->values, 0, max_count * sizeof(value_type)); + } + return n; + } + static btree_node* init_internal(internal_fields *f, btree_node *parent) { + btree_node *n = init_leaf(f, parent, kNodeValues); + f->leaf = 0; + if (!no_debug) { + memset(f->children, 0, sizeof(f->children)); + } + return n; + } + static btree_node* init_root(root_fields *f, btree_node *parent) { + btree_node *n = init_internal(f, parent); + f->rightmost = parent; + f->size = parent->count(); + return n; + } + void destroy() { + for (int i = 0; i < count(); ++i) { + value_destroy(i); + } + } + + private: + void value_init(int i) { + new (&fields_.values[i]) mutable_value_type; + } + void value_init(int i, const value_type &x) { + new (&fields_.values[i]) mutable_value_type(x); + } + void value_destroy(int i) { + fields_.values[i].~mutable_value_type(); + } + + private: + root_fields fields_; + + private: + btree_node(const btree_node&); + void operator=(const btree_node&); +}; + +template <typename Node, typename Reference, typename Pointer> +struct btree_iterator { + typedef typename Node::key_type key_type; + typedef typename Node::size_type size_type; + typedef typename Node::difference_type difference_type; + typedef typename Node::params_type params_type; + + typedef Node node_type; + typedef typename std::remove_const<Node>::type normal_node; + typedef const Node const_node; + typedef typename params_type::value_type value_type; + typedef typename params_type::pointer normal_pointer; + typedef typename params_type::reference normal_reference; + typedef typename params_type::const_pointer const_pointer; + typedef typename params_type::const_reference const_reference; + + typedef Pointer pointer; + typedef Reference reference; + typedef std::bidirectional_iterator_tag iterator_category; + + typedef btree_iterator< + normal_node, normal_reference, normal_pointer> iterator; + typedef btree_iterator< + const_node, const_reference, const_pointer> const_iterator; + typedef btree_iterator<Node, Reference, Pointer> self_type; + + btree_iterator() + : node(NULL), + position(-1) { + } + btree_iterator(Node *n, int p) + : node(n), + position(p) { + } + btree_iterator(const iterator &x) + : node(x.node), + position(x.position) { + } + + // Increment/decrement the iterator. + void increment() { + if (node->leaf() && ++position < node->count()) { + return; + } + increment_slow(); + } + void increment_by(int count); + void increment_slow(); + + void decrement() { + if (node->leaf() && --position >= 0) { + return; + } + decrement_slow(); + } + void decrement_slow(); + + bool operator==(const const_iterator &x) const { + return node == x.node && position == x.position; + } + bool operator!=(const const_iterator &x) const { + return node != x.node || position != x.position; + } + + // Accessors for the key/value the iterator is pointing at. + const key_type& key() const { + return node->key(position); + } + reference operator*() const { + return node->value(position); + } + pointer operator->() const { + return &node->value(position); + } + + self_type& operator++() { + increment(); + return *this; + } + self_type& operator--() { + decrement(); + return *this; + } + self_type operator++(int) { + self_type tmp = *this; + ++*this; + return tmp; + } + self_type operator--(int) { + self_type tmp = *this; + --*this; + return tmp; + } + + // The node in the tree the iterator is pointing at. + Node *node; + // The position within the node of the tree the iterator is pointing at. + int position; +}; + +// Dispatch helper class for using btree::internal_locate with plain compare. +struct btree_internal_locate_plain_compare { + template <typename K, typename T, typename Iter> + static std::pair<Iter, int> dispatch(const K &k, const T &t, Iter iter) { + return t.internal_locate_plain_compare(k, iter); + } +}; + +// Dispatch helper class for using btree::internal_locate with compare-to. +struct btree_internal_locate_compare_to { + template <typename K, typename T, typename Iter> + static std::pair<Iter, int> dispatch(const K &k, const T &t, Iter iter) { + return t.internal_locate_compare_to(k, iter); + } +}; + +template <typename Params> +class btree : public Params::key_compare { + typedef btree<Params> self_type; + typedef btree_node<Params> node_type; + typedef typename node_type::base_fields base_fields; + typedef typename node_type::leaf_fields leaf_fields; + typedef typename node_type::internal_fields internal_fields; + typedef typename node_type::root_fields root_fields; + typedef typename Params::is_key_compare_to is_key_compare_to; + + friend class btree_internal_locate_plain_compare; + friend class btree_internal_locate_compare_to; + typedef typename if_< + is_key_compare_to::value, + btree_internal_locate_compare_to, + btree_internal_locate_plain_compare>::type internal_locate_type; + + enum { + kNodeValues = node_type::kNodeValues, + kMinNodeValues = kNodeValues / 2, + kValueSize = node_type::kValueSize, + kExactMatch = node_type::kExactMatch, + kMatchMask = node_type::kMatchMask, + }; + + // A helper class to get the empty base class optimization for 0-size + // allocators. Base is internal_allocator_type. + // (e.g. empty_base_handle<internal_allocator_type, node_type*>). If Base is + // 0-size, the compiler doesn't have to reserve any space for it and + // sizeof(empty_base_handle) will simply be sizeof(Data). Google [empty base + // class optimization] for more details. + template <typename Base, typename Data> + struct empty_base_handle : public Base { + empty_base_handle(const Base &b, const Data &d) + : Base(b), + data(d) { + } + Data data; + }; + + struct node_stats { + node_stats(ssize_t l, ssize_t i) + : leaf_nodes(l), + internal_nodes(i) { + } + + node_stats& operator+=(const node_stats &x) { + leaf_nodes += x.leaf_nodes; + internal_nodes += x.internal_nodes; + return *this; + } + + ssize_t leaf_nodes; + ssize_t internal_nodes; + }; + + public: + typedef Params params_type; + typedef typename Params::key_type key_type; + typedef typename Params::data_type data_type; + typedef typename Params::mapped_type mapped_type; + typedef typename Params::value_type value_type; + typedef typename Params::key_compare key_compare; + typedef typename Params::pointer pointer; + typedef typename Params::const_pointer const_pointer; + typedef typename Params::reference reference; + typedef typename Params::const_reference const_reference; + typedef typename Params::size_type size_type; + typedef typename Params::difference_type difference_type; + typedef btree_iterator<node_type, reference, pointer> iterator; + typedef typename iterator::const_iterator const_iterator; + typedef std::reverse_iterator<const_iterator> const_reverse_iterator; + typedef std::reverse_iterator<iterator> reverse_iterator; + + typedef typename Params::allocator_type allocator_type; + typedef typename allocator_type::template rebind<char>::other + internal_allocator_type; + + public: + // Default constructor. + btree(const key_compare &comp, const allocator_type &alloc); + + // Copy constructor. + btree(const self_type &x); + + // Destructor. + ~btree() { + clear(); + } + + // Iterator routines. + iterator begin() { + return iterator(leftmost(), 0); + } + const_iterator begin() const { + return const_iterator(leftmost(), 0); + } + iterator end() { + return iterator(rightmost(), rightmost() ? rightmost()->count() : 0); + } + const_iterator end() const { + return const_iterator(rightmost(), rightmost() ? rightmost()->count() : 0); + } + reverse_iterator rbegin() { + return reverse_iterator(end()); + } + const_reverse_iterator rbegin() const { + return const_reverse_iterator(end()); + } + reverse_iterator rend() { + return reverse_iterator(begin()); + } + const_reverse_iterator rend() const { + return const_reverse_iterator(begin()); + } + + // Finds the first element whose key is not less than key. + iterator lower_bound(const key_type &key) { + return internal_end( + internal_lower_bound(key, iterator(root(), 0))); + } + const_iterator lower_bound(const key_type &key) const { + return internal_end( + internal_lower_bound(key, const_iterator(root(), 0))); + } + + // Finds the first element whose key is greater than key. + iterator upper_bound(const key_type &key) { + return internal_end( + internal_upper_bound(key, iterator(root(), 0))); + } + const_iterator upper_bound(const key_type &key) const { + return internal_end( + internal_upper_bound(key, const_iterator(root(), 0))); + } + + // Finds the range of values which compare equal to key. The first member of + // the returned pair is equal to lower_bound(key). The second member pair of + // the pair is equal to upper_bound(key). + std::pair<iterator,iterator> equal_range(const key_type &key) { + return std::make_pair(lower_bound(key), upper_bound(key)); + } + std::pair<const_iterator,const_iterator> equal_range(const key_type &key) const { + return std::make_pair(lower_bound(key), upper_bound(key)); + } + + // Inserts a value into the btree only if it does not already exist. The + // boolean return value indicates whether insertion succeeded or failed. The + // ValuePointer type is used to avoid instatiating the value unless the key + // is being inserted. Value is not dereferenced if the key already exists in + // the btree. See btree_map::operator[]. + template <typename ValuePointer> + std::pair<iterator,bool> insert_unique(const key_type &key, ValuePointer value); + + // Inserts a value into the btree only if it does not already exist. The + // boolean return value indicates whether insertion succeeded or failed. + std::pair<iterator,bool> insert_unique(const value_type &v) { + return insert_unique(params_type::key(v), &v); + } + + // Insert with hint. Check to see if the value should be placed immediately + // before position in the tree. If it does, then the insertion will take + // amortized constant time. If not, the insertion will take amortized + // logarithmic time as if a call to insert_unique(v) were made. + iterator insert_unique(iterator position, const value_type &v); + + // Insert a range of values into the btree. + template <typename InputIterator> + void insert_unique(InputIterator b, InputIterator e); + + // Inserts a value into the btree. The ValuePointer type is used to avoid + // instatiating the value unless the key is being inserted. Value is not + // dereferenced if the key already exists in the btree. See + // btree_map::operator[]. + template <typename ValuePointer> + iterator insert_multi(const key_type &key, ValuePointer value); + + // Inserts a value into the btree. + iterator insert_multi(const value_type &v) { + return insert_multi(params_type::key(v), &v); + } + + // Insert with hint. Check to see if the value should be placed immediately + // before position in the tree. If it does, then the insertion will take + // amortized constant time. If not, the insertion will take amortized + // logarithmic time as if a call to insert_multi(v) were made. + iterator insert_multi(iterator position, const value_type &v); + + // Insert a range of values into the btree. + template <typename InputIterator> + void insert_multi(InputIterator b, InputIterator e); + + void assign(const self_type &x); + + // Erase the specified iterator from the btree. The iterator must be valid + // (i.e. not equal to end()). Return an iterator pointing to the node after + // the one that was erased (or end() if none exists). + iterator erase(iterator iter); + + // Erases range. Returns the number of keys erased. + int erase(iterator begin, iterator end); + + // Erases the specified key from the btree. Returns 1 if an element was + // erased and 0 otherwise. + int erase_unique(const key_type &key); + + // Erases all of the entries matching the specified key from the + // btree. Returns the number of elements erased. + int erase_multi(const key_type &key); + + // Finds the iterator corresponding to a key or returns end() if the key is + // not present. + iterator find_unique(const key_type &key) { + return internal_end( + internal_find_unique(key, iterator(root(), 0))); + } + const_iterator find_unique(const key_type &key) const { + return internal_end( + internal_find_unique(key, const_iterator(root(), 0))); + } + iterator find_multi(const key_type &key) { + return internal_end( + internal_find_multi(key, iterator(root(), 0))); + } + const_iterator find_multi(const key_type &key) const { + return internal_end( + internal_find_multi(key, const_iterator(root(), 0))); + } + + // Returns a count of the number of times the key appears in the btree. + size_type count_unique(const key_type &key) const { + const_iterator begin = internal_find_unique( + key, const_iterator(root(), 0)); + if (!begin.node) { + // The key doesn't exist in the tree. + return 0; + } + return 1; + } + // Returns a count of the number of times the key appears in the btree. + size_type count_multi(const key_type &key) const { + return distance(lower_bound(key), upper_bound(key)); + } + + // Clear the btree, deleting all of the values it contains. + void clear(); + + // Swap the contents of *this and x. + void swap(self_type &x); + + // Assign the contents of x to *this. + self_type& operator=(const self_type &x) { + if (&x == this) { + // Don't copy onto ourselves. + return *this; + } + assign(x); + return *this; + } + + key_compare* mutable_key_comp() { + return this; + } + const key_compare& key_comp() const { + return *this; + } + bool compare_keys(const key_type &x, const key_type &y) const { + return btree_compare_keys(key_comp(), x, y); + } + + // Dump the btree to the specified ostream. Requires that operator<< is + // defined for Key and Value. + void dump(std::ostream &os) const { + if (root() != NULL) { + internal_dump(os, root(), 0); + } + } + + // Verifies the structure of the btree. + void verify() const; + + // Size routines. Note that empty() is slightly faster than doing size()==0. + size_type size() const { + if (empty()) return 0; + if (root()->leaf()) return root()->count(); + return root()->size(); + } + size_type max_size() const { return std::numeric_limits<size_type>::max(); } + bool empty() const { return root() == NULL; } + + // The height of the btree. An empty tree will have height 0. + size_type height() const { + size_type h = 0; + if (root()) { + // Count the length of the chain from the leftmost node up to the + // root. We actually count from the root back around to the level below + // the root, but the calculation is the same because of the circularity + // of that traversal. + const node_type *n = root(); + do { + ++h; + n = n->parent(); + } while (n != root()); + } + return h; + } + + // The number of internal, leaf and total nodes used by the btree. + size_type leaf_nodes() const { + return internal_stats(root()).leaf_nodes; + } + size_type internal_nodes() const { + return internal_stats(root()).internal_nodes; + } + size_type nodes() const { + node_stats stats = internal_stats(root()); + return stats.leaf_nodes + stats.internal_nodes; + } + + // The total number of bytes used by the btree. + size_type bytes_used() const { + node_stats stats = internal_stats(root()); + if (stats.leaf_nodes == 1 && stats.internal_nodes == 0) { + return sizeof(*this) + + sizeof(base_fields) + root()->max_count() * sizeof(value_type); + } else { + return sizeof(*this) + + sizeof(root_fields) - sizeof(internal_fields) + + stats.leaf_nodes * sizeof(leaf_fields) + + stats.internal_nodes * sizeof(internal_fields); + } + } + + // The average number of bytes used per value stored in the btree. + static double average_bytes_per_value() { + // Returns the number of bytes per value on a leaf node that is 75% + // full. Experimentally, this matches up nicely with the computed number of + // bytes per value in trees that had their values inserted in random order. + return sizeof(leaf_fields) / (kNodeValues * 0.75); + } + + // The fullness of the btree. Computed as the number of elements in the btree + // divided by the maximum number of elements a tree with the current number + // of nodes could hold. A value of 1 indicates perfect space + // utilization. Smaller values indicate space wastage. + double fullness() const { + return double(size()) / (nodes() * kNodeValues); + } + // The overhead of the btree structure in bytes per node. Computed as the + // total number of bytes used by the btree minus the number of bytes used for + // storing elements divided by the number of elements. + double overhead() const { + if (empty()) { + return 0.0; + } + return (bytes_used() - size() * kValueSize) / double(size()); + } + + private: + // Internal accessor routines. + node_type* root() { return root_.data; } + const node_type* root() const { return root_.data; } + node_type** mutable_root() { return &root_.data; } + + // The rightmost node is stored in the root node. + node_type* rightmost() { + return (!root() || root()->leaf()) ? root() : root()->rightmost(); + } + const node_type* rightmost() const { + return (!root() || root()->leaf()) ? root() : root()->rightmost(); + } + node_type** mutable_rightmost() { return root()->mutable_rightmost(); } + + // The leftmost node is stored as the parent of the root node. + node_type* leftmost() { return root() ? root()->parent() : NULL; } + const node_type* leftmost() const { return root() ? root()->parent() : NULL; } + + // The size of the tree is stored in the root node. + size_type* mutable_size() { return root()->mutable_size(); } + + // Allocator routines. + internal_allocator_type* mutable_internal_allocator() { + return static_cast<internal_allocator_type*>(&root_); + } + const internal_allocator_type& internal_allocator() const { + return *static_cast<const internal_allocator_type*>(&root_); + } + + // Node creation/deletion routines. + node_type* new_internal_node(node_type *parent) { + internal_fields *p = reinterpret_cast<internal_fields*>( + mutable_internal_allocator()->allocate(sizeof(internal_fields))); + return node_type::init_internal(p, parent); + } + node_type* new_internal_root_node() { + root_fields *p = reinterpret_cast<root_fields*>( + mutable_internal_allocator()->allocate(sizeof(root_fields))); + return node_type::init_root(p, root()->parent()); + } + node_type* new_leaf_node(node_type *parent) { + leaf_fields *p = reinterpret_cast<leaf_fields*>( + mutable_internal_allocator()->allocate(sizeof(leaf_fields))); + return node_type::init_leaf(p, parent, kNodeValues); + } + node_type* new_leaf_root_node(int max_count) { + leaf_fields *p = reinterpret_cast<leaf_fields*>( + mutable_internal_allocator()->allocate( + sizeof(base_fields) + max_count * sizeof(value_type))); + return node_type::init_leaf(p, reinterpret_cast<node_type*>(p), max_count); + } + void delete_internal_node(node_type *node) { + node->destroy(); + ceph_assert(node != root()); + mutable_internal_allocator()->deallocate( + reinterpret_cast<char*>(node), sizeof(internal_fields)); + } + void delete_internal_root_node() { + root()->destroy(); + mutable_internal_allocator()->deallocate( + reinterpret_cast<char*>(root()), sizeof(root_fields)); + } + void delete_leaf_node(node_type *node) { + node->destroy(); + mutable_internal_allocator()->deallocate( + reinterpret_cast<char*>(node), + sizeof(base_fields) + node->max_count() * sizeof(value_type)); + } + + // Rebalances or splits the node iter points to. + void rebalance_or_split(iterator *iter); + + // Merges the values of left, right and the delimiting key on their parent + // onto left, removing the delimiting key and deleting right. + void merge_nodes(node_type *left, node_type *right); + + // Tries to merge node with its left or right sibling, and failing that, + // rebalance with its left or right sibling. Returns true if a merge + // occurred, at which point it is no longer valid to access node. Returns + // false if no merging took place. + bool try_merge_or_rebalance(iterator *iter); + + // Tries to shrink the height of the tree by 1. + void try_shrink(); + + iterator internal_end(iterator iter) { + return iter.node ? iter : end(); + } + const_iterator internal_end(const_iterator iter) const { + return iter.node ? iter : end(); + } + + // Inserts a value into the btree immediately before iter. Requires that + // key(v) <= iter.key() and (--iter).key() <= key(v). + iterator internal_insert(iterator iter, const value_type &v); + + // Returns an iterator pointing to the first value >= the value "iter" is + // pointing at. Note that "iter" might be pointing to an invalid location as + // iter.position == iter.node->count(). This routine simply moves iter up in + // the tree to a valid location. + template <typename IterType> + static IterType internal_last(IterType iter); + + // Returns an iterator pointing to the leaf position at which key would + // reside in the tree. We provide 2 versions of internal_locate. The first + // version (internal_locate_plain_compare) always returns 0 for the second + // field of the pair. The second version (internal_locate_compare_to) is for + // the key-compare-to specialization and returns either kExactMatch (if the + // key was found in the tree) or -kExactMatch (if it wasn't) in the second + // field of the pair. The compare_to specialization allows the caller to + // avoid a subsequent comparison to determine if an exact match was made, + // speeding up string keys. + template <typename IterType> + std::pair<IterType, int> internal_locate( + const key_type &key, IterType iter) const; + template <typename IterType> + std::pair<IterType, int> internal_locate_plain_compare( + const key_type &key, IterType iter) const; + template <typename IterType> + std::pair<IterType, int> internal_locate_compare_to( + const key_type &key, IterType iter) const; + + // Internal routine which implements lower_bound(). + template <typename IterType> + IterType internal_lower_bound( + const key_type &key, IterType iter) const; + + // Internal routine which implements upper_bound(). + template <typename IterType> + IterType internal_upper_bound( + const key_type &key, IterType iter) const; + + // Internal routine which implements find_unique(). + template <typename IterType> + IterType internal_find_unique( + const key_type &key, IterType iter) const; + + // Internal routine which implements find_multi(). + template <typename IterType> + IterType internal_find_multi( + const key_type &key, IterType iter) const; + + // Deletes a node and all of its children. + void internal_clear(node_type *node); + + // Dumps a node and all of its children to the specified ostream. + void internal_dump(std::ostream &os, const node_type *node, int level) const; + + // Verifies the tree structure of node. + int internal_verify(const node_type *node, + const key_type *lo, const key_type *hi) const; + + node_stats internal_stats(const node_type *node) const { + if (!node) { + return node_stats(0, 0); + } + if (node->leaf()) { + return node_stats(1, 0); + } + node_stats res(0, 1); + for (int i = 0; i <= node->count(); ++i) { + res += internal_stats(node->child(i)); + } + return res; + } + + private: + empty_base_handle<internal_allocator_type, node_type*> root_; + + private: + // A never instantiated helper function that returns big_ if we have a + // key-compare-to functor or if R is bool and small_ otherwise. + template <typename R> + static typename if_< + if_<is_key_compare_to::value, + std::is_same<R, int>, + std::is_same<R, bool> >::type::value, + big_, small_>::type key_compare_checker(R); + + // A never instantiated helper function that returns the key comparison + // functor. + static key_compare key_compare_helper(); + + // Verify that key_compare returns a bool. This is similar to the way + // is_convertible in base/type_traits.h works. Note that key_compare_checker + // is never actually invoked. The compiler will select which + // key_compare_checker() to instantiate and then figure out the size of the + // return type of key_compare_checker() at compile time which we then check + // against the sizeof of big_. + COMPILE_ASSERT( + sizeof(key_compare_checker(key_compare_helper()(key_type(), key_type()))) == + sizeof(big_), + key_comparison_function_must_return_bool); + + // Note: We insist on kTargetValues, which is computed from + // Params::kTargetNodeSize, must fit the base_fields::field_type. + COMPILE_ASSERT(kNodeValues < + (1 << (8 * sizeof(typename base_fields::field_type))), + target_node_size_too_large); + + // Test the assumption made in setting kNodeValueSpace. + COMPILE_ASSERT(sizeof(base_fields) >= 2 * sizeof(void*), + node_space_assumption_incorrect); +}; + +//// +// btree_node methods +template <typename P> +inline void btree_node<P>::insert_value(int i, const value_type &x) { + ceph_assert(i <= count()); + value_init(count(), x); + for (int j = count(); j > i; --j) { + value_swap(j, this, j - 1); + } + set_count(count() + 1); + + if (!leaf()) { + ++i; + for (int j = count(); j > i; --j) { + *mutable_child(j) = child(j - 1); + child(j)->set_position(j); + } + *mutable_child(i) = NULL; + } +} + +template <typename P> +inline void btree_node<P>::remove_value(int i) { + if (!leaf()) { + ceph_assert(child(i + 1)->count() == 0); + for (int j = i + 1; j < count(); ++j) { + *mutable_child(j) = child(j + 1); + child(j)->set_position(j); + } + *mutable_child(count()) = NULL; + } + + set_count(count() - 1); + for (; i < count(); ++i) { + value_swap(i, this, i + 1); + } + value_destroy(i); +} + +template <typename P> +void btree_node<P>::rebalance_right_to_left(btree_node *src, int to_move) { + ceph_assert(parent() == src->parent()); + ceph_assert(position() + 1 == src->position()); + ceph_assert(src->count() >= count()); + ceph_assert(to_move >= 1); + ceph_assert(to_move <= src->count()); + + // Make room in the left node for the new values. + for (int i = 0; i < to_move; ++i) { + value_init(i + count()); + } + + // Move the delimiting value to the left node and the new delimiting value + // from the right node. + value_swap(count(), parent(), position()); + parent()->value_swap(position(), src, to_move - 1); + + // Move the values from the right to the left node. + for (int i = 1; i < to_move; ++i) { + value_swap(count() + i, src, i - 1); + } + // Shift the values in the right node to their correct position. + for (int i = to_move; i < src->count(); ++i) { + src->value_swap(i - to_move, src, i); + } + for (int i = 1; i <= to_move; ++i) { + src->value_destroy(src->count() - i); + } + + if (!leaf()) { + // Move the child pointers from the right to the left node. + for (int i = 0; i < to_move; ++i) { + set_child(1 + count() + i, src->child(i)); + } + for (int i = 0; i <= src->count() - to_move; ++i) { + ceph_assert(i + to_move <= src->max_count()); + src->set_child(i, src->child(i + to_move)); + *src->mutable_child(i + to_move) = NULL; + } + } + + // Fixup the counts on the src and dest nodes. + set_count(count() + to_move); + src->set_count(src->count() - to_move); +} + +template <typename P> +void btree_node<P>::rebalance_left_to_right(btree_node *dest, int to_move) { + ceph_assert(parent() == dest->parent()); + ceph_assert(position() + 1 == dest->position()); + ceph_assert(count() >= dest->count()); + ceph_assert(to_move >= 1); + ceph_assert(to_move <= count()); + + // Make room in the right node for the new values. + for (int i = 0; i < to_move; ++i) { + dest->value_init(i + dest->count()); + } + for (int i = dest->count() - 1; i >= 0; --i) { + dest->value_swap(i, dest, i + to_move); + } + + // Move the delimiting value to the right node and the new delimiting value + // from the left node. + dest->value_swap(to_move - 1, parent(), position()); + parent()->value_swap(position(), this, count() - to_move); + value_destroy(count() - to_move); + + // Move the values from the left to the right node. + for (int i = 1; i < to_move; ++i) { + value_swap(count() - to_move + i, dest, i - 1); + value_destroy(count() - to_move + i); + } + + if (!leaf()) { + // Move the child pointers from the left to the right node. + for (int i = dest->count(); i >= 0; --i) { + dest->set_child(i + to_move, dest->child(i)); + *dest->mutable_child(i) = NULL; + } + for (int i = 1; i <= to_move; ++i) { + dest->set_child(i - 1, child(count() - to_move + i)); + *mutable_child(count() - to_move + i) = NULL; + } + } + + // Fixup the counts on the src and dest nodes. + set_count(count() - to_move); + dest->set_count(dest->count() + to_move); +} + +template <typename P> +void btree_node<P>::split(btree_node *dest, int insert_position) { + ceph_assert(dest->count() == 0); + + // We bias the split based on the position being inserted. If we're + // inserting at the beginning of the left node then bias the split to put + // more values on the right node. If we're inserting at the end of the + // right node then bias the split to put more values on the left node. + if (insert_position == 0) { + dest->set_count(count() - 1); + } else if (insert_position == max_count()) { + dest->set_count(0); + } else { + dest->set_count(count() / 2); + } + set_count(count() - dest->count()); + ceph_assert(count() >= 1); + + // Move values from the left sibling to the right sibling. + for (int i = 0; i < dest->count(); ++i) { + dest->value_init(i); + value_swap(count() + i, dest, i); + value_destroy(count() + i); + } + + // The split key is the largest value in the left sibling. + set_count(count() - 1); + parent()->insert_value(position(), value_type()); + value_swap(count(), parent(), position()); + value_destroy(count()); + parent()->set_child(position() + 1, dest); + + if (!leaf()) { + for (int i = 0; i <= dest->count(); ++i) { + ceph_assert(child(count() + i + 1) != NULL); + dest->set_child(i, child(count() + i + 1)); + *mutable_child(count() + i + 1) = NULL; + } + } +} + +template <typename P> +void btree_node<P>::merge(btree_node *src) { + ceph_assert(parent() == src->parent()); + ceph_assert(position() + 1 == src->position()); + + // Move the delimiting value to the left node. + value_init(count()); + value_swap(count(), parent(), position()); + + // Move the values from the right to the left node. + for (int i = 0; i < src->count(); ++i) { + value_init(1 + count() + i); + value_swap(1 + count() + i, src, i); + src->value_destroy(i); + } + + if (!leaf()) { + // Move the child pointers from the right to the left node. + for (int i = 0; i <= src->count(); ++i) { + set_child(1 + count() + i, src->child(i)); + *src->mutable_child(i) = NULL; + } + } + + // Fixup the counts on the src and dest nodes. + set_count(1 + count() + src->count()); + src->set_count(0); + + // Remove the value on the parent node. + parent()->remove_value(position()); +} + +template <typename P> +void btree_node<P>::swap(btree_node *x) { + ceph_assert(leaf() == x->leaf()); + + // Swap the values. + for (int i = count(); i < x->count(); ++i) { + value_init(i); + } + for (int i = x->count(); i < count(); ++i) { + x->value_init(i); + } + int n = std::max(count(), x->count()); + for (int i = 0; i < n; ++i) { + value_swap(i, x, i); + } + for (int i = count(); i < x->count(); ++i) { + x->value_destroy(i); + } + for (int i = x->count(); i < count(); ++i) { + value_destroy(i); + } + + if (!leaf()) { + // Swap the child pointers. + for (int i = 0; i <= n; ++i) { + btree_swap_helper(*mutable_child(i), *x->mutable_child(i)); + } + for (int i = 0; i <= count(); ++i) { + x->child(i)->fields_.parent = x; + } + for (int i = 0; i <= x->count(); ++i) { + child(i)->fields_.parent = this; + } + } + + // Swap the counts. + btree_swap_helper(fields_.count, x->fields_.count); +} + +//// +// btree_iterator methods +template <typename N, typename R, typename P> +void btree_iterator<N, R, P>::increment_slow() { + if (node->leaf()) { + ceph_assert(position >= node->count()); + self_type save(*this); + while (position == node->count() && !node->is_root()) { + ceph_assert(node->parent()->child(node->position()) == node); + position = node->position(); + node = node->parent(); + } + if (position == node->count()) { + *this = save; + } + } else { + ceph_assert(position < node->count()); + node = node->child(position + 1); + while (!node->leaf()) { + node = node->child(0); + } + position = 0; + } +} + +template <typename N, typename R, typename P> +void btree_iterator<N, R, P>::increment_by(int count) { + while (count > 0) { + if (node->leaf()) { + int rest = node->count() - position; + position += std::min(rest, count); + count = count - rest; + if (position < node->count()) { + return; + } + } else { + --count; + } + increment_slow(); + } +} + +template <typename N, typename R, typename P> +void btree_iterator<N, R, P>::decrement_slow() { + if (node->leaf()) { + ceph_assert(position <= -1); + self_type save(*this); + while (position < 0 && !node->is_root()) { + ceph_assert(node->parent()->child(node->position()) == node); + position = node->position() - 1; + node = node->parent(); + } + if (position < 0) { + *this = save; + } + } else { + ceph_assert(position >= 0); + node = node->child(position); + while (!node->leaf()) { + node = node->child(node->count()); + } + position = node->count() - 1; + } +} + +//// +// btree methods +template <typename P> +btree<P>::btree(const key_compare &comp, const allocator_type &alloc) + : key_compare(comp), + root_(alloc, NULL) { +} + +template <typename P> +btree<P>::btree(const self_type &x) + : key_compare(x.key_comp()), + root_(x.internal_allocator(), NULL) { + assign(x); +} + +template <typename P> template <typename ValuePointer> +std::pair<typename btree<P>::iterator, bool> +btree<P>::insert_unique(const key_type &key, ValuePointer value) { + if (empty()) { + *mutable_root() = new_leaf_root_node(1); + } + + std::pair<iterator, int> res = internal_locate(key, iterator(root(), 0)); + iterator &iter = res.first; + if (res.second == kExactMatch) { + // The key already exists in the tree, do nothing. + return std::make_pair(internal_last(iter), false); + } else if (!res.second) { + iterator last = internal_last(iter); + if (last.node && !compare_keys(key, last.key())) { + // The key already exists in the tree, do nothing. + return std::make_pair(last, false); + } + } + + return std::make_pair(internal_insert(iter, *value), true); +} + +template <typename P> +inline typename btree<P>::iterator +btree<P>::insert_unique(iterator position, const value_type &v) { + if (!empty()) { + const key_type &key = params_type::key(v); + if (position == end() || compare_keys(key, position.key())) { + iterator prev = position; + if (position == begin() || compare_keys((--prev).key(), key)) { + // prev.key() < key < position.key() + return internal_insert(position, v); + } + } else if (compare_keys(position.key(), key)) { + iterator next = position; + ++next; + if (next == end() || compare_keys(key, next.key())) { + // position.key() < key < next.key() + return internal_insert(next, v); + } + } else { + // position.key() == key + return position; + } + } + return insert_unique(v).first; +} + +template <typename P> template <typename InputIterator> +void btree<P>::insert_unique(InputIterator b, InputIterator e) { + for (; b != e; ++b) { + insert_unique(end(), *b); + } +} + +template <typename P> template <typename ValuePointer> +typename btree<P>::iterator +btree<P>::insert_multi(const key_type &key, ValuePointer value) { + if (empty()) { + *mutable_root() = new_leaf_root_node(1); + } + + iterator iter = internal_upper_bound(key, iterator(root(), 0)); + if (!iter.node) { + iter = end(); + } + return internal_insert(iter, *value); +} + +template <typename P> +typename btree<P>::iterator +btree<P>::insert_multi(iterator position, const value_type &v) { + if (!empty()) { + const key_type &key = params_type::key(v); + if (position == end() || !compare_keys(position.key(), key)) { + iterator prev = position; + if (position == begin() || !compare_keys(key, (--prev).key())) { + // prev.key() <= key <= position.key() + return internal_insert(position, v); + } + } else { + iterator next = position; + ++next; + if (next == end() || !compare_keys(next.key(), key)) { + // position.key() < key <= next.key() + return internal_insert(next, v); + } + } + } + return insert_multi(v); +} + +template <typename P> template <typename InputIterator> +void btree<P>::insert_multi(InputIterator b, InputIterator e) { + for (; b != e; ++b) { + insert_multi(end(), *b); + } +} + +template <typename P> +void btree<P>::assign(const self_type &x) { + clear(); + + *mutable_key_comp() = x.key_comp(); + *mutable_internal_allocator() = x.internal_allocator(); + + // Assignment can avoid key comparisons because we know the order of the + // values is the same order we'll store them in. + for (const_iterator iter = x.begin(); iter != x.end(); ++iter) { + if (empty()) { + insert_multi(*iter); + } else { + // If the btree is not empty, we can just insert the new value at the end + // of the tree! + internal_insert(end(), *iter); + } + } +} + +template <typename P> +typename btree<P>::iterator btree<P>::erase(iterator iter) { + bool internal_delete = false; + if (!iter.node->leaf()) { + // Deletion of a value on an internal node. Swap the key with the largest + // value of our left child. This is easy, we just decrement iter. + iterator tmp_iter(iter--); + ceph_assert(iter.node->leaf()); + ceph_assert(!compare_keys(tmp_iter.key(), iter.key())); + iter.node->value_swap(iter.position, tmp_iter.node, tmp_iter.position); + internal_delete = true; + --*mutable_size(); + } else if (!root()->leaf()) { + --*mutable_size(); + } + + // Delete the key from the leaf. + iter.node->remove_value(iter.position); + + // We want to return the next value after the one we just erased. If we + // erased from an internal node (internal_delete == true), then the next + // value is ++(++iter). If we erased from a leaf node (internal_delete == + // false) then the next value is ++iter. Note that ++iter may point to an + // internal node and the value in the internal node may move to a leaf node + // (iter.node) when rebalancing is performed at the leaf level. + + // Merge/rebalance as we walk back up the tree. + iterator res(iter); + for (;;) { + if (iter.node == root()) { + try_shrink(); + if (empty()) { + return end(); + } + break; + } + if (iter.node->count() >= kMinNodeValues) { + break; + } + bool merged = try_merge_or_rebalance(&iter); + if (iter.node->leaf()) { + res = iter; + } + if (!merged) { + break; + } + iter.node = iter.node->parent(); + } + + // Adjust our return value. If we're pointing at the end of a node, advance + // the iterator. + if (res.position == res.node->count()) { + res.position = res.node->count() - 1; + ++res; + } + // If we erased from an internal node, advance the iterator. + if (internal_delete) { + ++res; + } + return res; +} + +template <typename P> +int btree<P>::erase(iterator begin, iterator end) { + int count = distance(begin, end); + for (int i = 0; i < count; i++) { + begin = erase(begin); + } + return count; +} + +template <typename P> +int btree<P>::erase_unique(const key_type &key) { + iterator iter = internal_find_unique(key, iterator(root(), 0)); + if (!iter.node) { + // The key doesn't exist in the tree, return nothing done. + return 0; + } + erase(iter); + return 1; +} + +template <typename P> +int btree<P>::erase_multi(const key_type &key) { + iterator begin = internal_lower_bound(key, iterator(root(), 0)); + if (!begin.node) { + // The key doesn't exist in the tree, return nothing done. + return 0; + } + // Delete all of the keys between begin and upper_bound(key). + iterator end = internal_end( + internal_upper_bound(key, iterator(root(), 0))); + return erase(begin, end); +} + +template <typename P> +void btree<P>::clear() { + if (root() != NULL) { + internal_clear(root()); + } + *mutable_root() = NULL; +} + +template <typename P> +void btree<P>::swap(self_type &x) { + std::swap(static_cast<key_compare&>(*this), static_cast<key_compare&>(x)); + std::swap(root_, x.root_); +} + +template <typename P> +void btree<P>::verify() const { + if (root() != NULL) { + ceph_assert(size() == internal_verify(root(), NULL, NULL)); + ceph_assert(leftmost() == (++const_iterator(root(), -1)).node); + ceph_assert(rightmost() == (--const_iterator(root(), root()->count())).node); + ceph_assert(leftmost()->leaf()); + ceph_assert(rightmost()->leaf()); + } else { + ceph_assert(size() == 0); + ceph_assert(leftmost() == NULL); + ceph_assert(rightmost() == NULL); + } +} + +template <typename P> +void btree<P>::rebalance_or_split(iterator *iter) { + node_type *&node = iter->node; + int &insert_position = iter->position; + ceph_assert(node->count() == node->max_count()); + + // First try to make room on the node by rebalancing. + node_type *parent = node->parent(); + if (node != root()) { + if (node->position() > 0) { + // Try rebalancing with our left sibling. + node_type *left = parent->child(node->position() - 1); + if (left->count() < left->max_count()) { + // We bias rebalancing based on the position being inserted. If we're + // inserting at the end of the right node then we bias rebalancing to + // fill up the left node. + int to_move = (left->max_count() - left->count()) / + (1 + (insert_position < left->max_count())); + to_move = std::max(1, to_move); + + if (((insert_position - to_move) >= 0) || + ((left->count() + to_move) < left->max_count())) { + left->rebalance_right_to_left(node, to_move); + + ceph_assert(node->max_count() - node->count() == to_move); + insert_position = insert_position - to_move; + if (insert_position < 0) { + insert_position = insert_position + left->count() + 1; + node = left; + } + + ceph_assert(node->count() < node->max_count()); + return; + } + } + } + + if (node->position() < parent->count()) { + // Try rebalancing with our right sibling. + node_type *right = parent->child(node->position() + 1); + if (right->count() < right->max_count()) { + // We bias rebalancing based on the position being inserted. If we're + // inserting at the beginning of the left node then we bias rebalancing + // to fill up the right node. + int to_move = (right->max_count() - right->count()) / + (1 + (insert_position > 0)); + to_move = std::max(1, to_move); + + if ((insert_position <= (node->count() - to_move)) || + ((right->count() + to_move) < right->max_count())) { + node->rebalance_left_to_right(right, to_move); + + if (insert_position > node->count()) { + insert_position = insert_position - node->count() - 1; + node = right; + } + + ceph_assert(node->count() < node->max_count()); + return; + } + } + } + + // Rebalancing failed, make sure there is room on the parent node for a new + // value. + if (parent->count() == parent->max_count()) { + iterator parent_iter(node->parent(), node->position()); + rebalance_or_split(&parent_iter); + } + } else { + // Rebalancing not possible because this is the root node. + if (root()->leaf()) { + // The root node is currently a leaf node: create a new root node and set + // the current root node as the child of the new root. + parent = new_internal_root_node(); + parent->set_child(0, root()); + *mutable_root() = parent; + ceph_assert(*mutable_rightmost() == parent->child(0)); + } else { + // The root node is an internal node. We do not want to create a new root + // node because the root node is special and holds the size of the tree + // and a pointer to the rightmost node. So we create a new internal node + // and move all of the items on the current root into the new node. + parent = new_internal_node(parent); + parent->set_child(0, parent); + parent->swap(root()); + node = parent; + } + } + + // Split the node. + node_type *split_node; + if (node->leaf()) { + split_node = new_leaf_node(parent); + node->split(split_node, insert_position); + if (rightmost() == node) { + *mutable_rightmost() = split_node; + } + } else { + split_node = new_internal_node(parent); + node->split(split_node, insert_position); + } + + if (insert_position > node->count()) { + insert_position = insert_position - node->count() - 1; + node = split_node; + } +} + +template <typename P> +void btree<P>::merge_nodes(node_type *left, node_type *right) { + left->merge(right); + if (right->leaf()) { + if (rightmost() == right) { + *mutable_rightmost() = left; + } + delete_leaf_node(right); + } else { + delete_internal_node(right); + } +} + +template <typename P> +bool btree<P>::try_merge_or_rebalance(iterator *iter) { + node_type *parent = iter->node->parent(); + if (iter->node->position() > 0) { + // Try merging with our left sibling. + node_type *left = parent->child(iter->node->position() - 1); + if ((1 + left->count() + iter->node->count()) <= left->max_count()) { + iter->position += 1 + left->count(); + merge_nodes(left, iter->node); + iter->node = left; + return true; + } + } + if (iter->node->position() < parent->count()) { + // Try merging with our right sibling. + node_type *right = parent->child(iter->node->position() + 1); + if ((1 + iter->node->count() + right->count()) <= right->max_count()) { + merge_nodes(iter->node, right); + return true; + } + // Try rebalancing with our right sibling. We don't perform rebalancing if + // we deleted the first element from iter->node and the node is not + // empty. This is a small optimization for the common pattern of deleting + // from the front of the tree. + if ((right->count() > kMinNodeValues) && + ((iter->node->count() == 0) || + (iter->position > 0))) { + int to_move = (right->count() - iter->node->count()) / 2; + to_move = std::min(to_move, right->count() - 1); + iter->node->rebalance_right_to_left(right, to_move); + return false; + } + } + if (iter->node->position() > 0) { + // Try rebalancing with our left sibling. We don't perform rebalancing if + // we deleted the last element from iter->node and the node is not + // empty. This is a small optimization for the common pattern of deleting + // from the back of the tree. + node_type *left = parent->child(iter->node->position() - 1); + if ((left->count() > kMinNodeValues) && + ((iter->node->count() == 0) || + (iter->position < iter->node->count()))) { + int to_move = (left->count() - iter->node->count()) / 2; + to_move = std::min(to_move, left->count() - 1); + left->rebalance_left_to_right(iter->node, to_move); + iter->position += to_move; + return false; + } + } + return false; +} + +template <typename P> +void btree<P>::try_shrink() { + if (root()->count() > 0) { + return; + } + // Deleted the last item on the root node, shrink the height of the tree. + if (root()->leaf()) { + ceph_assert(size() == 0); + delete_leaf_node(root()); + *mutable_root() = NULL; + } else { + node_type *child = root()->child(0); + if (child->leaf()) { + // The child is a leaf node so simply make it the root node in the tree. + child->make_root(); + delete_internal_root_node(); + *mutable_root() = child; + } else { + // The child is an internal node. We want to keep the existing root node + // so we move all of the values from the child node into the existing + // (empty) root node. + child->swap(root()); + delete_internal_node(child); + } + } +} + +template <typename P> template <typename IterType> +inline IterType btree<P>::internal_last(IterType iter) { + while (iter.node && iter.position == iter.node->count()) { + iter.position = iter.node->position(); + iter.node = iter.node->parent(); + if (iter.node->leaf()) { + iter.node = NULL; + } + } + return iter; +} + +template <typename P> +inline typename btree<P>::iterator +btree<P>::internal_insert(iterator iter, const value_type &v) { + if (!iter.node->leaf()) { + // We can't insert on an internal node. Instead, we'll insert after the + // previous value which is guaranteed to be on a leaf node. + --iter; + ++iter.position; + } + if (iter.node->count() == iter.node->max_count()) { + // Make room in the leaf for the new item. + if (iter.node->max_count() < kNodeValues) { + // Insertion into the root where the root is smaller that the full node + // size. Simply grow the size of the root node. + ceph_assert(iter.node == root()); + iter.node = new_leaf_root_node( + std::min<int>(kNodeValues, 2 * iter.node->max_count())); + iter.node->swap(root()); + delete_leaf_node(root()); + *mutable_root() = iter.node; + } else { + rebalance_or_split(&iter); + ++*mutable_size(); + } + } else if (!root()->leaf()) { + ++*mutable_size(); + } + iter.node->insert_value(iter.position, v); + return iter; +} + +template <typename P> template <typename IterType> +inline std::pair<IterType, int> btree<P>::internal_locate( + const key_type &key, IterType iter) const { + return internal_locate_type::dispatch(key, *this, iter); +} + +template <typename P> template <typename IterType> +inline std::pair<IterType, int> btree<P>::internal_locate_plain_compare( + const key_type &key, IterType iter) const { + for (;;) { + iter.position = iter.node->lower_bound(key, key_comp()); + if (iter.node->leaf()) { + break; + } + iter.node = iter.node->child(iter.position); + } + return std::make_pair(iter, 0); +} + +template <typename P> template <typename IterType> +inline std::pair<IterType, int> btree<P>::internal_locate_compare_to( + const key_type &key, IterType iter) const { + for (;;) { + int res = iter.node->lower_bound(key, key_comp()); + iter.position = res & kMatchMask; + if (res & kExactMatch) { + return std::make_pair(iter, static_cast<int>(kExactMatch)); + } + if (iter.node->leaf()) { + break; + } + iter.node = iter.node->child(iter.position); + } + return std::make_pair(iter, -kExactMatch); +} + +template <typename P> template <typename IterType> +IterType btree<P>::internal_lower_bound( + const key_type &key, IterType iter) const { + if (iter.node) { + for (;;) { + iter.position = + iter.node->lower_bound(key, key_comp()) & kMatchMask; + if (iter.node->leaf()) { + break; + } + iter.node = iter.node->child(iter.position); + } + iter = internal_last(iter); + } + return iter; +} + +template <typename P> template <typename IterType> +IterType btree<P>::internal_upper_bound( + const key_type &key, IterType iter) const { + if (iter.node) { + for (;;) { + iter.position = iter.node->upper_bound(key, key_comp()); + if (iter.node->leaf()) { + break; + } + iter.node = iter.node->child(iter.position); + } + iter = internal_last(iter); + } + return iter; +} + +template <typename P> template <typename IterType> +IterType btree<P>::internal_find_unique( + const key_type &key, IterType iter) const { + if (iter.node) { + std::pair<IterType, int> res = internal_locate(key, iter); + if (res.second == kExactMatch) { + return res.first; + } + if (!res.second) { + iter = internal_last(res.first); + if (iter.node && !compare_keys(key, iter.key())) { + return iter; + } + } + } + return IterType(NULL, 0); +} + +template <typename P> template <typename IterType> +IterType btree<P>::internal_find_multi( + const key_type &key, IterType iter) const { + if (iter.node) { + iter = internal_lower_bound(key, iter); + if (iter.node) { + iter = internal_last(iter); + if (iter.node && !compare_keys(key, iter.key())) { + return iter; + } + } + } + return IterType(NULL, 0); +} + +template <typename P> +void btree<P>::internal_clear(node_type *node) { + if (!node->leaf()) { + for (int i = 0; i <= node->count(); ++i) { + internal_clear(node->child(i)); + } + if (node == root()) { + delete_internal_root_node(); + } else { + delete_internal_node(node); + } + } else { + delete_leaf_node(node); + } +} + +template <typename P> +void btree<P>::internal_dump( + std::ostream &os, const node_type *node, int level) const { + for (int i = 0; i < node->count(); ++i) { + if (!node->leaf()) { + internal_dump(os, node->child(i), level + 1); + } + for (int j = 0; j < level; ++j) { + os << " "; + } + os << node->key(i) << " [" << level << "]\n"; + } + if (!node->leaf()) { + internal_dump(os, node->child(node->count()), level + 1); + } +} + +template <typename P> +int btree<P>::internal_verify( + const node_type *node, const key_type *lo, const key_type *hi) const { + ceph_assert(node->count() > 0); + ceph_assert(node->count() <= node->max_count()); + if (lo) { + ceph_assert(!compare_keys(node->key(0), *lo)); + } + if (hi) { + ceph_assert(!compare_keys(*hi, node->key(node->count() - 1))); + } + for (int i = 1; i < node->count(); ++i) { + ceph_assert(!compare_keys(node->key(i), node->key(i - 1))); + } + int count = node->count(); + if (!node->leaf()) { + for (int i = 0; i <= node->count(); ++i) { + ceph_assert(node->child(i) != NULL); + ceph_assert(node->child(i)->parent() == node); + ceph_assert(node->child(i)->position() == i); + count += internal_verify( + node->child(i), + (i == 0) ? lo : &node->key(i - 1), + (i == node->count()) ? hi : &node->key(i)); + } + } + return count; +} + +} // namespace btree + +#endif // UTIL_BTREE_BTREE_H__ |