mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-25 00:52:02 +00:00
370 lines
16 KiB
Plaintext
370 lines
16 KiB
Plaintext
// Copyright (c) 2005, Google Inc.
|
|
// All rights reserved.
|
|
//
|
|
// Redistribution and use in source and binary forms, with or without
|
|
// modification, are permitted provided that the following conditions are
|
|
// met:
|
|
//
|
|
// * Redistributions of source code must retain the above copyright
|
|
// notice, this list of conditions and the following disclaimer.
|
|
// * Redistributions in binary form must reproduce the above
|
|
// copyright notice, this list of conditions and the following disclaimer
|
|
// in the documentation and/or other materials provided with the
|
|
// distribution.
|
|
// * Neither the name of Google Inc. nor the names of its
|
|
// contributors may be used to endorse or promote products derived from
|
|
// this software without specific prior written permission.
|
|
//
|
|
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
|
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
// ----
|
|
//
|
|
// This is just a very thin wrapper over densehashtable.h, just
|
|
// like sgi stl's stl_hash_map is a very thin wrapper over
|
|
// stl_hashtable. The major thing we define is operator[], because
|
|
// we have a concept of a data_type which stl_hashtable doesn't
|
|
// (it only has a key and a value).
|
|
//
|
|
// NOTE: this is exactly like sparse_hash_map.h, with the word
|
|
// "sparse" replaced by "dense", except for the addition of
|
|
// set_empty_key().
|
|
//
|
|
// YOU MUST CALL SET_EMPTY_KEY() IMMEDIATELY AFTER CONSTRUCTION.
|
|
//
|
|
// Otherwise your program will die in mysterious ways. (Note if you
|
|
// use the constructor that takes an InputIterator range, you pass in
|
|
// the empty key in the constructor, rather than after. As a result,
|
|
// this constructor differs from the standard STL version.)
|
|
//
|
|
// In other respects, we adhere mostly to the STL semantics for
|
|
// hash-map. One important exception is that insert() may invalidate
|
|
// iterators entirely -- STL semantics are that insert() may reorder
|
|
// iterators, but they all still refer to something valid in the
|
|
// hashtable. Not so for us. Likewise, insert() may invalidate
|
|
// pointers into the hashtable. (Whether insert invalidates iterators
|
|
// and pointers depends on whether it results in a hashtable resize).
|
|
// On the plus side, delete() doesn't invalidate iterators or pointers
|
|
// at all, or even change the ordering of elements.
|
|
//
|
|
// Here are a few "power user" tips:
|
|
//
|
|
// 1) set_deleted_key():
|
|
// If you want to use erase() you *must* call set_deleted_key(),
|
|
// in addition to set_empty_key(), after construction.
|
|
// The deleted and empty keys must differ.
|
|
//
|
|
// 2) resize(0):
|
|
// When an item is deleted, its memory isn't freed right
|
|
// away. This allows you to iterate over a hashtable,
|
|
// and call erase(), without invalidating the iterator.
|
|
// To force the memory to be freed, call resize(0).
|
|
// For tr1 compatibility, this can also be called as rehash(0).
|
|
//
|
|
// 3) min_load_factor(0.0)
|
|
// Setting the minimum load factor to 0.0 guarantees that
|
|
// the hash table will never shrink.
|
|
//
|
|
// Roughly speaking:
|
|
// (1) dense_hash_map: fastest, uses the most memory unless entries are small
|
|
// (2) sparse_hash_map: slowest, uses the least memory
|
|
// (3) hash_map / unordered_map (STL): in the middle
|
|
//
|
|
// Typically I use sparse_hash_map when I care about space and/or when
|
|
// I need to save the hashtable on disk. I use hash_map otherwise. I
|
|
// don't personally use dense_hash_set ever; some people use it for
|
|
// small sets with lots of lookups.
|
|
//
|
|
// - dense_hash_map has, typically, about 78% memory overhead (if your
|
|
// data takes up X bytes, the hash_map uses .78X more bytes in overhead).
|
|
// - sparse_hash_map has about 4 bits overhead per entry.
|
|
// - sparse_hash_map can be 3-7 times slower than the others for lookup and,
|
|
// especially, inserts. See time_hash_map.cc for details.
|
|
//
|
|
// See /usr/(local/)?doc/sparsehash-*/dense_hash_map.html
|
|
// for information about how to use this class.
|
|
|
|
#ifndef _DENSE_HASH_MAP_H_
|
|
#define _DENSE_HASH_MAP_H_
|
|
|
|
#include <sparsehash/internal/sparseconfig.h>
|
|
#include <algorithm> // needed by stl_alloc
|
|
#include <functional> // for equal_to<>, select1st<>, etc
|
|
#include <memory> // for alloc
|
|
#include <utility> // for pair<>
|
|
#include <sparsehash/internal/densehashtable.h> // IWYU pragma: export
|
|
#include <sparsehash/internal/libc_allocator_with_realloc.h>
|
|
#include HASH_FUN_H // for hash<>
|
|
_START_GOOGLE_NAMESPACE_
|
|
|
|
template <class Key, class T,
|
|
class HashFcn = SPARSEHASH_HASH<Key>, // defined in sparseconfig.h
|
|
class EqualKey = std::equal_to<Key>,
|
|
class Alloc = libc_allocator_with_realloc<std::pair<const Key, T> > >
|
|
class dense_hash_map {
|
|
private:
|
|
// Apparently select1st is not stl-standard, so we define our own
|
|
struct SelectKey {
|
|
typedef const Key& result_type;
|
|
const Key& operator()(const std::pair<const Key, T>& p) const {
|
|
return p.first;
|
|
}
|
|
};
|
|
struct SetKey {
|
|
void operator()(std::pair<const Key, T>* value, const Key& new_key) const {
|
|
*const_cast<Key*>(&value->first) = new_key;
|
|
// It would be nice to clear the rest of value here as well, in
|
|
// case it's taking up a lot of memory. We do this by clearing
|
|
// the value. This assumes T has a zero-arg constructor!
|
|
value->second = T();
|
|
}
|
|
};
|
|
// For operator[].
|
|
struct DefaultValue {
|
|
std::pair<const Key, T> operator()(const Key& key) {
|
|
return std::make_pair(key, T());
|
|
}
|
|
};
|
|
|
|
// The actual data
|
|
typedef dense_hashtable<std::pair<const Key, T>, Key, HashFcn, SelectKey,
|
|
SetKey, EqualKey, Alloc> ht;
|
|
ht rep;
|
|
|
|
public:
|
|
typedef typename ht::key_type key_type;
|
|
typedef T data_type;
|
|
typedef T mapped_type;
|
|
typedef typename ht::value_type value_type;
|
|
typedef typename ht::hasher hasher;
|
|
typedef typename ht::key_equal key_equal;
|
|
typedef Alloc allocator_type;
|
|
|
|
typedef typename ht::size_type size_type;
|
|
typedef typename ht::difference_type difference_type;
|
|
typedef typename ht::pointer pointer;
|
|
typedef typename ht::const_pointer const_pointer;
|
|
typedef typename ht::reference reference;
|
|
typedef typename ht::const_reference const_reference;
|
|
|
|
typedef typename ht::iterator iterator;
|
|
typedef typename ht::const_iterator const_iterator;
|
|
typedef typename ht::local_iterator local_iterator;
|
|
typedef typename ht::const_local_iterator const_local_iterator;
|
|
|
|
// Iterator functions
|
|
iterator begin() { return rep.begin(); }
|
|
iterator end() { return rep.end(); }
|
|
const_iterator begin() const { return rep.begin(); }
|
|
const_iterator end() const { return rep.end(); }
|
|
|
|
|
|
// These come from tr1's unordered_map. For us, a bucket has 0 or 1 elements.
|
|
local_iterator begin(size_type i) { return rep.begin(i); }
|
|
local_iterator end(size_type i) { return rep.end(i); }
|
|
const_local_iterator begin(size_type i) const { return rep.begin(i); }
|
|
const_local_iterator end(size_type i) const { return rep.end(i); }
|
|
|
|
// Accessor functions
|
|
allocator_type get_allocator() const { return rep.get_allocator(); }
|
|
hasher hash_funct() const { return rep.hash_funct(); }
|
|
hasher hash_function() const { return hash_funct(); }
|
|
key_equal key_eq() const { return rep.key_eq(); }
|
|
|
|
|
|
// Constructors
|
|
explicit dense_hash_map(size_type expected_max_items_in_table = 0,
|
|
const hasher& hf = hasher(),
|
|
const key_equal& eql = key_equal(),
|
|
const allocator_type& alloc = allocator_type())
|
|
: rep(expected_max_items_in_table, hf, eql, SelectKey(), SetKey(), alloc) {
|
|
}
|
|
|
|
template <class InputIterator>
|
|
dense_hash_map(InputIterator f, InputIterator l,
|
|
const key_type& empty_key_val,
|
|
size_type expected_max_items_in_table = 0,
|
|
const hasher& hf = hasher(),
|
|
const key_equal& eql = key_equal(),
|
|
const allocator_type& alloc = allocator_type())
|
|
: rep(expected_max_items_in_table, hf, eql, SelectKey(), SetKey(), alloc) {
|
|
set_empty_key(empty_key_val);
|
|
rep.insert(f, l);
|
|
}
|
|
// We use the default copy constructor
|
|
// We use the default operator=()
|
|
// We use the default destructor
|
|
|
|
void clear() { rep.clear(); }
|
|
// This clears the hash map without resizing it down to the minimum
|
|
// bucket count, but rather keeps the number of buckets constant
|
|
void clear_no_resize() { rep.clear_no_resize(); }
|
|
void swap(dense_hash_map& hs) { rep.swap(hs.rep); }
|
|
|
|
|
|
// Functions concerning size
|
|
size_type size() const { return rep.size(); }
|
|
size_type max_size() const { return rep.max_size(); }
|
|
bool empty() const { return rep.empty(); }
|
|
size_type bucket_count() const { return rep.bucket_count(); }
|
|
size_type max_bucket_count() const { return rep.max_bucket_count(); }
|
|
|
|
// These are tr1 methods. bucket() is the bucket the key is or would be in.
|
|
size_type bucket_size(size_type i) const { return rep.bucket_size(i); }
|
|
size_type bucket(const key_type& key) const { return rep.bucket(key); }
|
|
float load_factor() const {
|
|
return size() * 1.0f / bucket_count();
|
|
}
|
|
float max_load_factor() const {
|
|
float shrink, grow;
|
|
rep.get_resizing_parameters(&shrink, &grow);
|
|
return grow;
|
|
}
|
|
void max_load_factor(float new_grow) {
|
|
float shrink, grow;
|
|
rep.get_resizing_parameters(&shrink, &grow);
|
|
rep.set_resizing_parameters(shrink, new_grow);
|
|
}
|
|
// These aren't tr1 methods but perhaps ought to be.
|
|
float min_load_factor() const {
|
|
float shrink, grow;
|
|
rep.get_resizing_parameters(&shrink, &grow);
|
|
return shrink;
|
|
}
|
|
void min_load_factor(float new_shrink) {
|
|
float shrink, grow;
|
|
rep.get_resizing_parameters(&shrink, &grow);
|
|
rep.set_resizing_parameters(new_shrink, grow);
|
|
}
|
|
// Deprecated; use min_load_factor() or max_load_factor() instead.
|
|
void set_resizing_parameters(float shrink, float grow) {
|
|
rep.set_resizing_parameters(shrink, grow);
|
|
}
|
|
|
|
void resize(size_type hint) { rep.resize(hint); }
|
|
void rehash(size_type hint) { resize(hint); } // the tr1 name
|
|
|
|
// Lookup routines
|
|
iterator find(const key_type& key) { return rep.find(key); }
|
|
const_iterator find(const key_type& key) const { return rep.find(key); }
|
|
|
|
data_type& operator[](const key_type& key) { // This is our value-add!
|
|
// If key is in the hashtable, returns find(key)->second,
|
|
// otherwise returns insert(value_type(key, T()).first->second.
|
|
// Note it does not create an empty T unless the find fails.
|
|
return rep.template find_or_insert<DefaultValue>(key).second;
|
|
}
|
|
|
|
size_type count(const key_type& key) const { return rep.count(key); }
|
|
|
|
std::pair<iterator, iterator> equal_range(const key_type& key) {
|
|
return rep.equal_range(key);
|
|
}
|
|
std::pair<const_iterator, const_iterator> equal_range(const key_type& key)
|
|
const {
|
|
return rep.equal_range(key);
|
|
}
|
|
|
|
|
|
// Insertion routines
|
|
std::pair<iterator, bool> insert(const value_type& obj) {
|
|
return rep.insert(obj);
|
|
}
|
|
template <class InputIterator> void insert(InputIterator f, InputIterator l) {
|
|
rep.insert(f, l);
|
|
}
|
|
void insert(const_iterator f, const_iterator l) {
|
|
rep.insert(f, l);
|
|
}
|
|
// Required for std::insert_iterator; the passed-in iterator is ignored.
|
|
iterator insert(iterator, const value_type& obj) {
|
|
return insert(obj).first;
|
|
}
|
|
|
|
// Deletion and empty routines
|
|
// THESE ARE NON-STANDARD! I make you specify an "impossible" key
|
|
// value to identify deleted and empty buckets. You can change the
|
|
// deleted key as time goes on, or get rid of it entirely to be insert-only.
|
|
void set_empty_key(const key_type& key) { // YOU MUST CALL THIS!
|
|
rep.set_empty_key(value_type(key, data_type())); // rep wants a value
|
|
}
|
|
key_type empty_key() const {
|
|
return rep.empty_key().first; // rep returns a value
|
|
}
|
|
|
|
void set_deleted_key(const key_type& key) { rep.set_deleted_key(key); }
|
|
void clear_deleted_key() { rep.clear_deleted_key(); }
|
|
key_type deleted_key() const { return rep.deleted_key(); }
|
|
|
|
// These are standard
|
|
size_type erase(const key_type& key) { return rep.erase(key); }
|
|
void erase(iterator it) { rep.erase(it); }
|
|
void erase(iterator f, iterator l) { rep.erase(f, l); }
|
|
|
|
|
|
// Comparison
|
|
bool operator==(const dense_hash_map& hs) const { return rep == hs.rep; }
|
|
bool operator!=(const dense_hash_map& hs) const { return rep != hs.rep; }
|
|
|
|
|
|
// I/O -- this is an add-on for writing hash map to disk
|
|
//
|
|
// For maximum flexibility, this does not assume a particular
|
|
// file type (though it will probably be a FILE *). We just pass
|
|
// the fp through to rep.
|
|
|
|
// If your keys and values are simple enough, you can pass this
|
|
// serializer to serialize()/unserialize(). "Simple enough" means
|
|
// value_type is a POD type that contains no pointers. Note,
|
|
// however, we don't try to normalize endianness.
|
|
typedef typename ht::NopointerSerializer NopointerSerializer;
|
|
|
|
// serializer: a class providing operator()(OUTPUT*, const value_type&)
|
|
// (writing value_type to OUTPUT). You can specify a
|
|
// NopointerSerializer object if appropriate (see above).
|
|
// fp: either a FILE*, OR an ostream*/subclass_of_ostream*, OR a
|
|
// pointer to a class providing size_t Write(const void*, size_t),
|
|
// which writes a buffer into a stream (which fp presumably
|
|
// owns) and returns the number of bytes successfully written.
|
|
// Note basic_ostream<not_char> is not currently supported.
|
|
template <typename ValueSerializer, typename OUTPUT>
|
|
bool serialize(ValueSerializer serializer, OUTPUT* fp) {
|
|
return rep.serialize(serializer, fp);
|
|
}
|
|
|
|
// serializer: a functor providing operator()(INPUT*, value_type*)
|
|
// (reading from INPUT and into value_type). You can specify a
|
|
// NopointerSerializer object if appropriate (see above).
|
|
// fp: either a FILE*, OR an istream*/subclass_of_istream*, OR a
|
|
// pointer to a class providing size_t Read(void*, size_t),
|
|
// which reads into a buffer from a stream (which fp presumably
|
|
// owns) and returns the number of bytes successfully read.
|
|
// Note basic_istream<not_char> is not currently supported.
|
|
// NOTE: Since value_type is std::pair<const Key, T>, ValueSerializer
|
|
// may need to do a const cast in order to fill in the key.
|
|
template <typename ValueSerializer, typename INPUT>
|
|
bool unserialize(ValueSerializer serializer, INPUT* fp) {
|
|
return rep.unserialize(serializer, fp);
|
|
}
|
|
};
|
|
|
|
// We need a global swap as well
|
|
template <class Key, class T, class HashFcn, class EqualKey, class Alloc>
|
|
inline void swap(dense_hash_map<Key, T, HashFcn, EqualKey, Alloc>& hm1,
|
|
dense_hash_map<Key, T, HashFcn, EqualKey, Alloc>& hm2) {
|
|
hm1.swap(hm2);
|
|
}
|
|
|
|
_END_GOOGLE_NAMESPACE_
|
|
|
|
#endif /* _DENSE_HASH_MAP_H_ */
|