foundationdb/fdbserver/art.h

356 lines
9.2 KiB
C++

/*
* art.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2020 Apple Inc. and the FoundationDB project authors
*
* 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.
*/
#include <stdint.h>
#include "fdbclient/FDBTypes.h"
#include "flow/Arena.h"
#include "flow/Platform.h"
#ifndef ART_H
#define ART_H
struct art_iterator;
struct art_tree {
enum ART_NODE_TYPE : uint8_t {
ART_LEAF = 0,
ART_NODE4 = 1,
ART_NODE16 = 2,
ART_NODE48 = 3,
ART_NODE256 = 4,
ART_NODE4_KV = 5,
ART_NODE16_KV = 6,
ART_NODE48_KV = 7,
ART_NODE256_KV = 8
};
#define ART_MIN_LEAF_UNSET 1UL
#define ART_LEAF_MATCH_KEY 1
#define ART_LEAF_SMALLER_KEY 2
#define ART_LEAF_LARGER_KEY 3
#define ART_I_FOUND 2
#define ART_I_DEPTH 3
#define ART_I_BACKTRACK 4
#define ART_NEXT 1
#define ART_PREV -1
#define ART_NEITHER 0
//#define ART_IS_LEAF(x) ( (*((ART_NODE_TYPE*)x) == ART_LEAF))
template <class T>
static inline bool ART_IS_LEAF(T const& x) {
return *((ART_NODE_TYPE*)x) == ART_LEAF;
}
#define ART_LEAF_RAW(x) ((art_leaf*)(x))
#define ART_LEAF_DISPL(x) fat_leaf_offset[(x)->type]
#define ART_FAT_NODE_LEAF(node_ptr) (*((art_leaf**)(((char*)(node_ptr)) + ART_LEAF_DISPL(node_ptr))))
// In Bytes
// This is needed so that we can pre-allocate a static stack to perform efficient backtracking in iterative_bound
#define ART_MAX_KEY_LEN 10000
#define _mm_cmpge_epu8(a, b) _mm_cmpeq_epi8(_mm_max_epu8(a, b), a)
#define _mm_cmple_epu8(a, b) _mm_cmpge_epu8(b, a)
#define _mm_cmpgt_epu8(a, b) _mm_xor_si128(_mm_cmple_epu8(a, b), _mm_set1_epi8(-1))
#define _mm_cmplt_epu8(a, b) _mm_cmpgt_epu8(b, a)
#define ART_MAX_PREFIX_LEN 10
/**
* This struct is included as part
* of all the various node sizes
*/
struct art_node {
ART_NODE_TYPE type;
uint8_t num_children;
uint32_t partial_len;
unsigned char partial[ART_MAX_PREFIX_LEN];
};
/**
* Represents a leaf. These are
* of arbitrary size, as they include the key.
* Note that the first two fields must be the same as in art_node
*/
struct art_leaf {
ART_NODE_TYPE type;
void* value;
art_leaf* prev = nullptr;
art_leaf* next = nullptr;
KeyRef key;
art_leaf(const KeyRef& k, void* v) : type(ART_LEAF), value(v), key(k.begin(), k.size()) {}
art_leaf(const uint8_t* ptr, int len, void* v) : type(ART_LEAF), value(v), key(ptr, len) {}
};
/**
* Small node with only 4 children
*/
struct art_node4 {
art_node n;
unsigned char keys[4];
art_node* children[4];
};
/**
* Node with 16 children
*/
struct art_node16 {
art_node n;
unsigned char keys[16];
art_node* children[16];
};
/**
* Node with 48 children, but
* a full 256 byte field.
*/
struct art_node48 {
art_node n;
unsigned char keys[256];
art_node* children[48];
};
/**
* Full node with 256 children
*/
struct art_node256 {
art_node n;
art_node* children[256];
};
/**
* Small node with only 4 children
*/
struct art_node4_kv {
art_node4 n;
art_leaf* leaf;
};
/**
* Node with 16 children
*/
struct art_node16_kv {
art_node16 n;
art_leaf* leaf;
};
/**
* Node with 48 children, but
* a full 256 byte field.
*/
struct art_node48_kv {
art_node48 n;
art_leaf* leaf;
};
/**
* Full node with 256 children
*/
struct art_node256_kv {
art_node256 n;
art_leaf* leaf;
};
private:
art_node* root;
uint64_t size;
Arena* arena;
static int fat_leaf_offset[9];
static int node_sizes[9];
static int check_bound_node(art_node* n, const KeyRef& k, int* depth_p, art_leaf** result, bool strict);
static int art_bound_leaf(art_node* n, const KeyRef& k, int depth, art_leaf** result);
static art_leaf* minimum(art_node* n);
static art_leaf* maximum(art_node* n);
static int leaf_matches_signed(art_leaf* n, const KeyRef& k, int depth);
static int leaf_matches(const art_leaf* n, const KeyRef& k, int depth);
static int signed_prefix_mismatch(art_node* n, const KeyRef& k, int depth, art_leaf** min_leaf, bool find_min);
static int prefix_mismatch(art_node* n, KeyRef& k, int depth, art_leaf** minout);
static art_leaf* minimum_kv(art_node* n);
static art_node** find_child(art_node* n, unsigned char c);
static void find_next(art_node* n, unsigned char c, art_node** out);
static void find_prev(art_node* n, unsigned char c, art_node** out);
static int art_next_prev(art_node* n, unsigned char c, art_node** out);
void art_bound_iterative(art_node* n, const KeyRef& k, int depth, art_leaf** result, bool strict);
static inline int min(int a, int b) { return (a < b) ? a : b; }
static inline void* SET_LEAF(void* x) {
(*((uint8_t*)x) = 0);
return x;
}
static int check_prefix(const art_node* n, const KeyRef& k, int depth);
void recursive_delete_binary(art_node* n, art_node** ref, const KeyRef& k, int depth);
void remove_child(art_node* n, art_node** ref, unsigned char c, art_node** l, int depth);
// needs this pointer to do allocation
art_node* alloc_node(ART_NODE_TYPE type);
art_node* alloc_kv_node(ART_NODE_TYPE type);
art_leaf* make_leaf(const KeyRef& k, void* value);
static void remove_fat_child(art_node* n, art_node** ref, int depth);
static void remove_fat_child4(art_node4_kv* n, art_node** ref, int depth);
static void remove_child4(art_node4* n, art_node** ref, art_node** l, int depth);
static void remove_fat_child16(art_node16_kv* n, art_node** ref);
void remove_child16(art_node16* n, art_node** ref, art_node** l);
static void remove_fat_child48(art_node48_kv* n, art_node** ref);
void remove_child48(art_node48* n, art_node** ref, unsigned char c);
static void remove_fat_child256(art_node256_kv* n, art_node** ref);
void remove_child256(art_node256* n, art_node** ref, unsigned char c);
static void copy_header(art_node* dest, art_node* src);
art_leaf* iterative_insert(art_node* root,
art_node** root_ptr,
KeyRef& k,
void* value,
int depth,
int* old,
int replace_existing);
art_leaf*
insert_leaf(art_node* n, art_node** ref, const KeyRef& k, void* value, int depth, int* old, int replace_existing);
art_leaf* insert_fat_node(art_node* n,
art_node** ref,
const KeyRef& k,
void* value,
int depth,
int* old,
art_leaf* min_of_n,
int replace_existing);
art_leaf* insert_internal_node(art_node* n,
art_node** ref,
const KeyRef& k,
void* value,
int depth,
int* old,
art_leaf* min_of_n,
int prefix_diff,
int replace_existing);
art_leaf*
insert_child(art_node* n, art_node** ref, const KeyRef& k, void* value, int depth, int* old, int replace_existing);
static inline int longest_common_prefix(const KeyRef& k1, const KeyRef& k2, int depth);
static void insert_after(art_leaf* l_new, art_leaf* l_existing);
static void insert_before(art_leaf* l_new, art_leaf* l_existing);
void add_child(art_node* n, art_node** ref, unsigned char c, void* child);
void add_child256(art_node256* n, art_node** ref, unsigned char c, void* child);
void add_child48(art_node48* n, art_node** ref, unsigned char c, void* child);
void add_child16(art_node16* n, art_node** ref, unsigned char c, void* child);
void add_child4(art_node4* n, art_node** ref, unsigned char c, void* child);
public:
art_tree(Arena& a) {
this->arena = &a;
this->root = alloc_node(ART_NODE4); // Sentinel node. Also needed for empty key
this->size = 0;
}
art_iterator lower_bound(const KeyRef& k);
art_iterator upper_bound(const KeyRef& k);
art_iterator insert(KeyRef& key, void* value);
art_iterator insert_if_absent(KeyRef& key, void* value, int* replaced);
void erase(const art_iterator& it);
uint64_t count() { return size; }
}; // art_tree
struct art_iterator {
private:
art_tree::art_leaf* leaf;
public:
art_iterator(art_tree::art_leaf* l) { leaf = l; }
art_iterator(const art_iterator& i) { leaf = i.leaf; }
art_iterator() { leaf = nullptr; }
art_iterator& operator++() {
leaf = leaf->next;
return (*this);
}
art_iterator& operator--() {
leaf = leaf->prev;
return (*this);
}
bool operator==(const art_iterator& other) const { return leaf == other.leaf; }
bool operator!=(const art_iterator& other) const { return leaf != other.leaf; }
const KeyRef& key() const { return leaf->key; }
void* value() const { return leaf->value; }
void** value_ptr() { return &(leaf->value); }
};
#endif // ART_H