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add sparsehash/densehashmap headers - a faster hashmap impl for our p…

…urposes - refs #1629
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commit 05aa5e41191a7922a1f81d9441804341bea96c5b 1 parent db80da4
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369 deps/sparsehash/dense_hash_map
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+// 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_ */
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1,319 deps/sparsehash/internal/densehashtable.h
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+// 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.
+
+// ---
+//
+// A dense hashtable is a particular implementation of
+// a hashtable: one that is meant to minimize memory allocation.
+// It does this by using an array to store all the data. We
+// steal a value from the key space to indicate "empty" array
+// elements (ie indices where no item lives) and another to indicate
+// "deleted" elements.
+//
+// (Note it is possible to change the value of the delete key
+// on the fly; you can even remove it, though after that point
+// the hashtable is insert_only until you set it again. The empty
+// value however can't be changed.)
+//
+// To minimize allocation and pointer overhead, we use internal
+// probing, in which the hashtable is a single table, and collisions
+// are resolved by trying to insert again in another bucket. The
+// most cache-efficient internal probing schemes are linear probing
+// (which suffers, alas, from clumping) and quadratic probing, which
+// is what we implement by default.
+//
+// Type requirements: value_type is required to be Copy Constructible
+// and Default Constructible. It is not required to be (and commonly
+// isn't) Assignable.
+//
+// You probably shouldn't use this code directly. Use dense_hash_map<>
+// or dense_hash_set<> instead.
+
+// You can change the following below:
+// HT_OCCUPANCY_PCT -- how full before we double size
+// HT_EMPTY_PCT -- how empty before we halve size
+// HT_MIN_BUCKETS -- default smallest bucket size
+//
+// You can also change enlarge_factor (which defaults to
+// HT_OCCUPANCY_PCT), and shrink_factor (which defaults to
+// HT_EMPTY_PCT) with set_resizing_parameters().
+//
+// How to decide what values to use?
+// shrink_factor's default of .4 * OCCUPANCY_PCT, is probably good.
+// HT_MIN_BUCKETS is probably unnecessary since you can specify
+// (indirectly) the starting number of buckets at construct-time.
+// For enlarge_factor, you can use this chart to try to trade-off
+// expected lookup time to the space taken up. By default, this
+// code uses quadratic probing, though you can change it to linear
+// via JUMP_ below if you really want to.
+//
+// From http://www.augustana.ca/~mohrj/courses/1999.fall/csc210/lecture_notes/hashing.html
+// NUMBER OF PROBES / LOOKUP Successful Unsuccessful
+// Quadratic collision resolution 1 - ln(1-L) - L/2 1/(1-L) - L - ln(1-L)
+// Linear collision resolution [1+1/(1-L)]/2 [1+1/(1-L)2]/2
+//
+// -- enlarge_factor -- 0.10 0.50 0.60 0.75 0.80 0.90 0.99
+// QUADRATIC COLLISION RES.
+// probes/successful lookup 1.05 1.44 1.62 2.01 2.21 2.85 5.11
+// probes/unsuccessful lookup 1.11 2.19 2.82 4.64 5.81 11.4 103.6
+// LINEAR COLLISION RES.
+// probes/successful lookup 1.06 1.5 1.75 2.5 3.0 5.5 50.5
+// probes/unsuccessful lookup 1.12 2.5 3.6 8.5 13.0 50.0 5000.0
+
+#ifndef _DENSEHASHTABLE_H_
+#define _DENSEHASHTABLE_H_
+
+#include <sparsehash/internal/sparseconfig.h>
+#include <assert.h>
+#include <stdio.h> // for FILE, fwrite, fread
+#include <algorithm> // For swap(), eg
+#include <iterator> // For iterator tags
+#include <limits> // for numeric_limits
+#include <memory> // For uninitialized_fill
+#include <utility> // for pair
+#include <sparsehash/internal/hashtable-common.h>
+#include <sparsehash/internal/libc_allocator_with_realloc.h>
+#include <sparsehash/type_traits.h>
+#include <stdexcept> // For length_error
+
+_START_GOOGLE_NAMESPACE_
+
+namespace base { // just to make google->opensource transition easier
+using GOOGLE_NAMESPACE::true_type;
+using GOOGLE_NAMESPACE::false_type;
+using GOOGLE_NAMESPACE::integral_constant;
+using GOOGLE_NAMESPACE::is_same;
+using GOOGLE_NAMESPACE::remove_const;
+}
+
+// The probing method
+// Linear probing
+// #define JUMP_(key, num_probes) ( 1 )
+// Quadratic probing
+#define JUMP_(key, num_probes) ( num_probes )
+
+// Hashtable class, used to implement the hashed associative containers
+// hash_set and hash_map.
+
+// Value: what is stored in the table (each bucket is a Value).
+// Key: something in a 1-to-1 correspondence to a Value, that can be used
+// to search for a Value in the table (find() takes a Key).
+// HashFcn: Takes a Key and returns an integer, the more unique the better.
+// ExtractKey: given a Value, returns the unique Key associated with it.
+// Must inherit from unary_function, or at least have a
+// result_type enum indicating the return type of operator().
+// SetKey: given a Value* and a Key, modifies the value such that
+// ExtractKey(value) == key. We guarantee this is only called
+// with key == deleted_key or key == empty_key.
+// EqualKey: Given two Keys, says whether they are the same (that is,
+// if they are both associated with the same Value).
+// Alloc: STL allocator to use to allocate memory.
+
+template <class Value, class Key, class HashFcn,
+ class ExtractKey, class SetKey, class EqualKey, class Alloc>
+class dense_hashtable;
+
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+struct dense_hashtable_iterator;
+
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+struct dense_hashtable_const_iterator;
+
+// We're just an array, but we need to skip over empty and deleted elements
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+struct dense_hashtable_iterator {
+ private:
+ typedef typename A::template rebind<V>::other value_alloc_type;
+
+ public:
+ typedef dense_hashtable_iterator<V,K,HF,ExK,SetK,EqK,A> iterator;
+ typedef dense_hashtable_const_iterator<V,K,HF,ExK,SetK,EqK,A> const_iterator;
+
+ typedef std::forward_iterator_tag iterator_category; // very little defined!
+ typedef V value_type;
+ typedef typename value_alloc_type::difference_type difference_type;
+ typedef typename value_alloc_type::size_type size_type;
+ typedef typename value_alloc_type::reference reference;
+ typedef typename value_alloc_type::pointer pointer;
+
+ // "Real" constructor and default constructor
+ dense_hashtable_iterator(const dense_hashtable<V,K,HF,ExK,SetK,EqK,A> *h,
+ pointer it, pointer it_end, bool advance)
+ : ht(h), pos(it), end(it_end) {
+ if (advance) advance_past_empty_and_deleted();
+ }
+ dense_hashtable_iterator() { }
+ // The default destructor is fine; we don't define one
+ // The default operator= is fine; we don't define one
+
+ // Happy dereferencer
+ reference operator*() const { return *pos; }
+ pointer operator->() const { return &(operator*()); }
+
+ // Arithmetic. The only hard part is making sure that
+ // we're not on an empty or marked-deleted array element
+ void advance_past_empty_and_deleted() {
+ while ( pos != end && (ht->test_empty(*this) || ht->test_deleted(*this)) )
+ ++pos;
+ }
+ iterator& operator++() {
+ assert(pos != end); ++pos; advance_past_empty_and_deleted(); return *this;
+ }
+ iterator operator++(int) { iterator tmp(*this); ++*this; return tmp; }
+
+ // Comparison.
+ bool operator==(const iterator& it) const { return pos == it.pos; }
+ bool operator!=(const iterator& it) const { return pos != it.pos; }
+
+
+ // The actual data
+ const dense_hashtable<V,K,HF,ExK,SetK,EqK,A> *ht;
+ pointer pos, end;
+};
+
+
+// Now do it all again, but with const-ness!
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+struct dense_hashtable_const_iterator {
+ private:
+ typedef typename A::template rebind<V>::other value_alloc_type;
+
+ public:
+ typedef dense_hashtable_iterator<V,K,HF,ExK,SetK,EqK,A> iterator;
+ typedef dense_hashtable_const_iterator<V,K,HF,ExK,SetK,EqK,A> const_iterator;
+
+ typedef std::forward_iterator_tag iterator_category; // very little defined!
+ typedef V value_type;
+ typedef typename value_alloc_type::difference_type difference_type;
+ typedef typename value_alloc_type::size_type size_type;
+ typedef typename value_alloc_type::const_reference reference;
+ typedef typename value_alloc_type::const_pointer pointer;
+
+ // "Real" constructor and default constructor
+ dense_hashtable_const_iterator(
+ const dense_hashtable<V,K,HF,ExK,SetK,EqK,A> *h,
+ pointer it, pointer it_end, bool advance)
+ : ht(h), pos(it), end(it_end) {
+ if (advance) advance_past_empty_and_deleted();
+ }
+ dense_hashtable_const_iterator()
+ : ht(NULL), pos(pointer()), end(pointer()) { }
+ // This lets us convert regular iterators to const iterators
+ dense_hashtable_const_iterator(const iterator &it)
+ : ht(it.ht), pos(it.pos), end(it.end) { }
+ // The default destructor is fine; we don't define one
+ // The default operator= is fine; we don't define one
+
+ // Happy dereferencer
+ reference operator*() const { return *pos; }
+ pointer operator->() const { return &(operator*()); }
+
+ // Arithmetic. The only hard part is making sure that
+ // we're not on an empty or marked-deleted array element
+ void advance_past_empty_and_deleted() {
+ while ( pos != end && (ht->test_empty(*this) || ht->test_deleted(*this)) )
+ ++pos;
+ }
+ const_iterator& operator++() {
+ assert(pos != end); ++pos; advance_past_empty_and_deleted(); return *this;
+ }
+ const_iterator operator++(int) { const_iterator tmp(*this); ++*this; return tmp; }
+
+ // Comparison.
+ bool operator==(const const_iterator& it) const { return pos == it.pos; }
+ bool operator!=(const const_iterator& it) const { return pos != it.pos; }
+
+
+ // The actual data
+ const dense_hashtable<V,K,HF,ExK,SetK,EqK,A> *ht;
+ pointer pos, end;
+};
+
+template <class Value, class Key, class HashFcn,
+ class ExtractKey, class SetKey, class EqualKey, class Alloc>
+class dense_hashtable {
+ private:
+ typedef typename Alloc::template rebind<Value>::other value_alloc_type;
+
+ public:
+ typedef Key key_type;
+ typedef Value value_type;
+ typedef HashFcn hasher;
+ typedef EqualKey key_equal;
+ typedef Alloc allocator_type;
+
+ typedef typename value_alloc_type::size_type size_type;
+ typedef typename value_alloc_type::difference_type difference_type;
+ typedef typename value_alloc_type::reference reference;
+ typedef typename value_alloc_type::const_reference const_reference;
+ typedef typename value_alloc_type::pointer pointer;
+ typedef typename value_alloc_type::const_pointer const_pointer;
+ typedef dense_hashtable_iterator<Value, Key, HashFcn,
+ ExtractKey, SetKey, EqualKey, Alloc>
+ iterator;
+
+ typedef dense_hashtable_const_iterator<Value, Key, HashFcn,
+ ExtractKey, SetKey, EqualKey, Alloc>
+ const_iterator;
+
+ // These come from tr1. For us they're the same as regular iterators.
+ typedef iterator local_iterator;
+ typedef const_iterator const_local_iterator;
+
+ // How full we let the table get before we resize, by default.
+ // Knuth says .8 is good -- higher causes us to probe too much,
+ // though it saves memory.
+ static const int HT_OCCUPANCY_PCT; // defined at the bottom of this file
+
+ // How empty we let the table get before we resize lower, by default.
+ // (0.0 means never resize lower.)
+ // It should be less than OCCUPANCY_PCT / 2 or we thrash resizing
+ static const int HT_EMPTY_PCT; // defined at the bottom of this file
+
+ // Minimum size we're willing to let hashtables be.
+ // Must be a power of two, and at least 4.
+ // Note, however, that for a given hashtable, the initial size is a
+ // function of the first constructor arg, and may be >HT_MIN_BUCKETS.
+ static const size_type HT_MIN_BUCKETS = 4;
+
+ // By default, if you don't specify a hashtable size at
+ // construction-time, we use this size. Must be a power of two, and
+ // at least HT_MIN_BUCKETS.
+ static const size_type HT_DEFAULT_STARTING_BUCKETS = 32;
+
+ // ITERATOR FUNCTIONS
+ iterator begin() { return iterator(this, table,
+ table + num_buckets, true); }
+ iterator end() { return iterator(this, table + num_buckets,
+ table + num_buckets, true); }
+ const_iterator begin() const { return const_iterator(this, table,
+ table+num_buckets,true);}
+ const_iterator end() const { return const_iterator(this, table + num_buckets,
+ table+num_buckets,true);}
+
+ // These come from tr1 unordered_map. They iterate over 'bucket' n.
+ // We'll just consider bucket n to be the n-th element of the table.
+ local_iterator begin(size_type i) {
+ return local_iterator(this, table + i, table + i+1, false);
+ }
+ local_iterator end(size_type i) {
+ local_iterator it = begin(i);
+ if (!test_empty(i) && !test_deleted(i))
+ ++it;
+ return it;
+ }
+ const_local_iterator begin(size_type i) const {
+ return const_local_iterator(this, table + i, table + i+1, false);
+ }
+ const_local_iterator end(size_type i) const {
+ const_local_iterator it = begin(i);
+ if (!test_empty(i) && !test_deleted(i))
+ ++it;
+ return it;
+ }
+
+ // ACCESSOR FUNCTIONS for the things we templatize on, basically
+ hasher hash_funct() const { return settings; }
+ key_equal key_eq() const { return key_info; }
+ allocator_type get_allocator() const {
+ return allocator_type(val_info);
+ }
+
+ // Accessor function for statistics gathering.
+ int num_table_copies() const { return settings.num_ht_copies(); }
+
+ private:
+ // Annoyingly, we can't copy values around, because they might have
+ // const components (they're probably pair<const X, Y>). We use
+ // explicit destructor invocation and placement new to get around
+ // this. Arg.
+ void set_value(pointer dst, const_reference src) {
+ dst->~value_type(); // delete the old value, if any
+ new(dst) value_type(src);
+ }
+
+ void destroy_buckets(size_type first, size_type last) {
+ for ( ; first != last; ++first)
+ table[first].~value_type();
+ }
+
+ // DELETE HELPER FUNCTIONS
+ // This lets the user describe a key that will indicate deleted
+ // table entries. This key should be an "impossible" entry --
+ // if you try to insert it for real, you won't be able to retrieve it!
+ // (NB: while you pass in an entire value, only the key part is looked
+ // at. This is just because I don't know how to assign just a key.)
+ private:
+ void squash_deleted() { // gets rid of any deleted entries we have
+ if ( num_deleted ) { // get rid of deleted before writing
+ dense_hashtable tmp(*this); // copying will get rid of deleted
+ swap(tmp); // now we are tmp
+ }
+ assert(num_deleted == 0);
+ }
+
+ // Test if the given key is the deleted indicator. Requires
+ // num_deleted > 0, for correctness of read(), and because that
+ // guarantees that key_info.delkey is valid.
+ bool test_deleted_key(const key_type& key) const {
+ assert(num_deleted > 0);
+ return equals(key_info.delkey, key);
+ }
+
+ public:
+ void set_deleted_key(const key_type &key) {
+ // the empty indicator (if specified) and the deleted indicator
+ // must be different
+ assert((!settings.use_empty() || !equals(key, get_key(val_info.emptyval)))
+ && "Passed the empty-key to set_deleted_key");
+ // It's only safe to change what "deleted" means if we purge deleted guys
+ squash_deleted();
+ settings.set_use_deleted(true);
+ key_info.delkey = key;
+ }
+ void clear_deleted_key() {
+ squash_deleted();
+ settings.set_use_deleted(false);
+ }
+ key_type deleted_key() const {
+ assert(settings.use_deleted()
+ && "Must set deleted key before calling deleted_key");
+ return key_info.delkey;
+ }
+
+ // These are public so the iterators can use them
+ // True if the item at position bucknum is "deleted" marker
+ bool test_deleted(size_type bucknum) const {
+ // Invariant: !use_deleted() implies num_deleted is 0.
+ assert(settings.use_deleted() || num_deleted == 0);
+ return num_deleted > 0 && test_deleted_key(get_key(table[bucknum]));
+ }
+ bool test_deleted(const iterator &it) const {
+ // Invariant: !use_deleted() implies num_deleted is 0.
+ assert(settings.use_deleted() || num_deleted == 0);
+ return num_deleted > 0 && test_deleted_key(get_key(*it));
+ }
+ bool test_deleted(const const_iterator &it) const {
+ // Invariant: !use_deleted() implies num_deleted is 0.
+ assert(settings.use_deleted() || num_deleted == 0);
+ return num_deleted > 0 && test_deleted_key(get_key(*it));
+ }
+
+ private:
+ void check_use_deleted(const char* caller) {
+ (void)caller; // could log it if the assert failed
+ assert(settings.use_deleted());
+ }
+
+ // Set it so test_deleted is true. true if object didn't used to be deleted.
+ bool set_deleted(iterator &it) {
+ check_use_deleted("set_deleted()");
+ bool retval = !test_deleted(it);
+ // &* converts from iterator to value-type.
+ set_key(&(*it), key_info.delkey);
+ return retval;
+ }
+ // Set it so test_deleted is false. true if object used to be deleted.
+ bool clear_deleted(iterator &it) {
+ check_use_deleted("clear_deleted()");
+ // Happens automatically when we assign something else in its place.
+ return test_deleted(it);
+ }
+
+ // We also allow to set/clear the deleted bit on a const iterator.
+ // We allow a const_iterator for the same reason you can delete a
+ // const pointer: it's convenient, and semantically you can't use
+ // 'it' after it's been deleted anyway, so its const-ness doesn't
+ // really matter.
+ bool set_deleted(const_iterator &it) {
+ check_use_deleted("set_deleted()");
+ bool retval = !test_deleted(it);
+ set_key(const_cast<pointer>(&(*it)), key_info.delkey);
+ return retval;
+ }
+ // Set it so test_deleted is false. true if object used to be deleted.
+ bool clear_deleted(const_iterator &it) {
+ check_use_deleted("clear_deleted()");
+ return test_deleted(it);
+ }
+
+ // EMPTY HELPER FUNCTIONS
+ // This lets the user describe a key that will indicate empty (unused)
+ // table entries. This key should be an "impossible" entry --
+ // if you try to insert it for real, you won't be able to retrieve it!
+ // (NB: while you pass in an entire value, only the key part is looked
+ // at. This is just because I don't know how to assign just a key.)
+ public:
+ // These are public so the iterators can use them
+ // True if the item at position bucknum is "empty" marker
+ bool test_empty(size_type bucknum) const {
+ assert(settings.use_empty()); // we always need to know what's empty!
+ return equals(get_key(val_info.emptyval), get_key(table[bucknum]));
+ }
+ bool test_empty(const iterator &it) const {
+ assert(settings.use_empty()); // we always need to know what's empty!
+ return equals(get_key(val_info.emptyval), get_key(*it));
+ }
+ bool test_empty(const const_iterator &it) const {
+ assert(settings.use_empty()); // we always need to know what's empty!
+ return equals(get_key(val_info.emptyval), get_key(*it));
+ }
+
+ private:
+ void fill_range_with_empty(pointer table_start, pointer table_end) {
+ std::uninitialized_fill(table_start, table_end, val_info.emptyval);
+ }
+
+ public:
+ // TODO(csilvers): change all callers of this to pass in a key instead,
+ // and take a const key_type instead of const value_type.
+ void set_empty_key(const_reference val) {
+ // Once you set the empty key, you can't change it
+ assert(!settings.use_empty() && "Calling set_empty_key multiple times");
+ // The deleted indicator (if specified) and the empty indicator
+ // must be different.
+ assert((!settings.use_deleted() || !equals(get_key(val), key_info.delkey))
+ && "Setting the empty key the same as the deleted key");
+ settings.set_use_empty(true);
+ set_value(&val_info.emptyval, val);
+
+ assert(!table); // must set before first use
+ // num_buckets was set in constructor even though table was NULL
+ table = val_info.allocate(num_buckets);
+ assert(table);
+ fill_range_with_empty(table, table + num_buckets);
+ }
+ // TODO(user): return a key_type rather than a value_type
+ value_type empty_key() const {
+ assert(settings.use_empty());
+ return val_info.emptyval;
+ }
+
+ // FUNCTIONS CONCERNING SIZE
+ public:
+ size_type size() const { return num_elements - num_deleted; }
+ size_type max_size() const { return val_info.max_size(); }
+ bool empty() const { return size() == 0; }
+ size_type bucket_count() const { return num_buckets; }
+ size_type max_bucket_count() const { return max_size(); }
+ size_type nonempty_bucket_count() const { return num_elements; }
+ // These are tr1 methods. Their idea of 'bucket' doesn't map well to
+ // what we do. We just say every bucket has 0 or 1 items in it.
+ size_type bucket_size(size_type i) const {
+ return begin(i) == end(i) ? 0 : 1;
+ }
+
+ private:
+ // Because of the above, size_type(-1) is never legal; use it for errors
+ static const size_type ILLEGAL_BUCKET = size_type(-1);
+
+ // Used after a string of deletes. Returns true if we actually shrunk.
+ // TODO(csilvers): take a delta so we can take into account inserts
+ // done after shrinking. Maybe make part of the Settings class?
+ bool maybe_shrink() {
+ assert(num_elements >= num_deleted);
+ assert((bucket_count() & (bucket_count()-1)) == 0); // is a power of two
+ assert(bucket_count() >= HT_MIN_BUCKETS);
+ bool retval = false;
+
+ // If you construct a hashtable with < HT_DEFAULT_STARTING_BUCKETS,
+ // we'll never shrink until you get relatively big, and we'll never
+ // shrink below HT_DEFAULT_STARTING_BUCKETS. Otherwise, something
+ // like "dense_hash_set<int> x; x.insert(4); x.erase(4);" will
+ // shrink us down to HT_MIN_BUCKETS buckets, which is too small.
+ const size_type num_remain = num_elements - num_deleted;
+ const size_type shrink_threshold = settings.shrink_threshold();
+ if (shrink_threshold > 0 && num_remain < shrink_threshold &&
+ bucket_count() > HT_DEFAULT_STARTING_BUCKETS) {
+ const float shrink_factor = settings.shrink_factor();
+ size_type sz = bucket_count() / 2; // find how much we should shrink
+ while (sz > HT_DEFAULT_STARTING_BUCKETS &&
+ num_remain < sz * shrink_factor) {
+ sz /= 2; // stay a power of 2
+ }
+ dense_hashtable tmp(*this, sz); // Do the actual resizing
+ swap(tmp); // now we are tmp
+ retval = true;
+ }
+ settings.set_consider_shrink(false); // because we just considered it
+ return retval;
+ }
+
+ // We'll let you resize a hashtable -- though this makes us copy all!
+ // When you resize, you say, "make it big enough for this many more elements"
+ // Returns true if we actually resized, false if size was already ok.
+ bool resize_delta(size_type delta) {
+ bool did_resize = false;
+ if ( settings.consider_shrink() ) { // see if lots of deletes happened
+ if ( maybe_shrink() )
+ did_resize = true;
+ }
+ if (num_elements >=
+ (std::numeric_limits<size_type>::max)() - delta) {
+ throw std::length_error("resize overflow");
+ }
+ if ( bucket_count() >= HT_MIN_BUCKETS &&
+ (num_elements + delta) <= settings.enlarge_threshold() )
+ return did_resize; // we're ok as we are
+
+ // Sometimes, we need to resize just to get rid of all the
+ // "deleted" buckets that are clogging up the hashtable. So when
+ // deciding whether to resize, count the deleted buckets (which
+ // are currently taking up room). But later, when we decide what
+ // size to resize to, *don't* count deleted buckets, since they
+ // get discarded during the resize.
+ const size_type needed_size = settings.min_buckets(num_elements + delta, 0);
+ if ( needed_size <= bucket_count() ) // we have enough buckets
+ return did_resize;
+
+ size_type resize_to =
+ settings.min_buckets(num_elements - num_deleted + delta, bucket_count());
+
+ if (resize_to < needed_size && // may double resize_to
+ resize_to < (std::numeric_limits<size_type>::max)() / 2) {
+ // This situation means that we have enough deleted elements,
+ // that once we purge them, we won't actually have needed to
+ // grow. But we may want to grow anyway: if we just purge one
+ // element, say, we'll have to grow anyway next time we
+ // insert. Might as well grow now, since we're already going
+ // through the trouble of copying (in order to purge the
+ // deleted elements).
+ const size_type target =
+ static_cast<size_type>(settings.shrink_size(resize_to*2));
+ if (num_elements - num_deleted + delta >= target) {
+ // Good, we won't be below the shrink threshhold even if we double.
+ resize_to *= 2;
+ }
+ }
+ dense_hashtable tmp(*this, resize_to);
+ swap(tmp); // now we are tmp
+ return true;
+ }
+
+ // We require table be not-NULL and empty before calling this.
+ void resize_table(size_type /*old_size*/, size_type new_size,
+ base::true_type) {
+ table = val_info.realloc_or_die(table, new_size);
+ }
+
+ void resize_table(size_type old_size, size_type new_size, base::false_type) {
+ val_info.deallocate(table, old_size);
+ table = val_info.allocate(new_size);
+ }
+
+ // Used to actually do the rehashing when we grow/shrink a hashtable
+ void copy_from(const dense_hashtable &ht, size_type min_buckets_wanted) {
+ clear_to_size(settings.min_buckets(ht.size(), min_buckets_wanted));
+
+ // We use a normal iterator to get non-deleted bcks from ht
+ // We could use insert() here, but since we know there are
+ // no duplicates and no deleted items, we can be more efficient
+ assert((bucket_count() & (bucket_count()-1)) == 0); // a power of two
+ for ( const_iterator it = ht.begin(); it != ht.end(); ++it ) {
+ size_type num_probes = 0; // how many times we've probed
+ size_type bucknum;
+ const size_type bucket_count_minus_one = bucket_count() - 1;
+ for (bucknum = hash(get_key(*it)) & bucket_count_minus_one;
+ !test_empty(bucknum); // not empty
+ bucknum = (bucknum + JUMP_(key, num_probes)) & bucket_count_minus_one) {
+ ++num_probes;
+ assert(num_probes < bucket_count()
+ && "Hashtable is full: an error in key_equal<> or hash<>");
+ }
+ set_value(&table[bucknum], *it); // copies the value to here
+ num_elements++;
+ }
+ settings.inc_num_ht_copies();
+ }
+
+ // Required by the spec for hashed associative container
+ public:
+ // Though the docs say this should be num_buckets, I think it's much
+ // more useful as num_elements. As a special feature, calling with
+ // req_elements==0 will cause us to shrink if we can, saving space.
+ void resize(size_type req_elements) { // resize to this or larger
+ if ( settings.consider_shrink() || req_elements == 0 )
+ maybe_shrink();
+ if ( req_elements > num_elements )
+ resize_delta(req_elements - num_elements);
+ }
+
+ // Get and change the value of shrink_factor and enlarge_factor. The
+ // description at the beginning of this file explains how to choose
+ // the values. Setting the shrink parameter to 0.0 ensures that the
+ // table never shrinks.
+ void get_resizing_parameters(float* shrink, float* grow) const {
+ *shrink = settings.shrink_factor();
+ *grow = settings.enlarge_factor();
+ }
+ void set_resizing_parameters(float shrink, float grow) {
+ settings.set_resizing_parameters(shrink, grow);
+ settings.reset_thresholds(bucket_count());
+ }
+
+ // CONSTRUCTORS -- as required by the specs, we take a size,
+ // but also let you specify a hashfunction, key comparator,
+ // and key extractor. We also define a copy constructor and =.
+ // DESTRUCTOR -- needs to free the table
+ explicit dense_hashtable(size_type expected_max_items_in_table = 0,
+ const HashFcn& hf = HashFcn(),
+ const EqualKey& eql = EqualKey(),
+ const ExtractKey& ext = ExtractKey(),
+ const SetKey& set = SetKey(),
+ const Alloc& alloc = Alloc())
+ : settings(hf),
+ key_info(ext, set, eql),
+ num_deleted(0),
+ num_elements(0),
+ num_buckets(expected_max_items_in_table == 0
+ ? HT_DEFAULT_STARTING_BUCKETS
+ : settings.min_buckets(expected_max_items_in_table, 0)),
+ val_info(alloc_impl<value_alloc_type>(alloc)),
+ table(NULL) {
+ // table is NULL until emptyval is set. However, we set num_buckets
+ // here so we know how much space to allocate once emptyval is set
+ settings.reset_thresholds(bucket_count());
+ }
+
+ // As a convenience for resize(), we allow an optional second argument
+ // which lets you make this new hashtable a different size than ht
+ dense_hashtable(const dense_hashtable& ht,
+ size_type min_buckets_wanted = HT_DEFAULT_STARTING_BUCKETS)
+ : settings(ht.settings),
+ key_info(ht.key_info),
+ num_deleted(0),
+ num_elements(0),
+ num_buckets(0),
+ val_info(ht.val_info),
+ table(NULL) {
+ if (!ht.settings.use_empty()) {
+ // If use_empty isn't set, copy_from will crash, so we do our own copying.
+ assert(ht.empty());
+ num_buckets = settings.min_buckets(ht.size(), min_buckets_wanted);
+ settings.reset_thresholds(bucket_count());
+ return;
+ }
+ settings.reset_thresholds(bucket_count());
+ copy_from(ht, min_buckets_wanted); // copy_from() ignores deleted entries
+ }
+
+ dense_hashtable& operator= (const dense_hashtable& ht) {
+ if (&ht == this) return *this; // don't copy onto ourselves
+ if (!ht.settings.use_empty()) {
+ assert(ht.empty());
+ dense_hashtable empty_table(ht); // empty table with ht's thresholds
+ this->swap(empty_table);
+ return *this;
+ }
+ settings = ht.settings;
+ key_info = ht.key_info;
+ set_value(&val_info.emptyval, ht.val_info.emptyval);
+ // copy_from() calls clear and sets num_deleted to 0 too
+ copy_from(ht, HT_MIN_BUCKETS);
+ // we purposefully don't copy the allocator, which may not be copyable
+ return *this;
+ }
+
+ ~dense_hashtable() {
+ if (table) {
+ destroy_buckets(0, num_buckets);
+ val_info.deallocate(table, num_buckets);
+ }
+ }
+
+ // Many STL algorithms use swap instead of copy constructors
+ void swap(dense_hashtable& ht) {
+ std::swap(settings, ht.settings);
+ std::swap(key_info, ht.key_info);
+ std::swap(num_deleted, ht.num_deleted);
+ std::swap(num_elements, ht.num_elements);
+ std::swap(num_buckets, ht.num_buckets);
+ { value_type tmp; // for annoying reasons, swap() doesn't work
+ set_value(&tmp, val_info.emptyval);
+ set_value(&val_info.emptyval, ht.val_info.emptyval);
+ set_value(&ht.val_info.emptyval, tmp);
+ }
+ std::swap(table, ht.table);
+ settings.reset_thresholds(bucket_count()); // also resets consider_shrink
+ ht.settings.reset_thresholds(ht.bucket_count());
+ // we purposefully don't swap the allocator, which may not be swap-able
+ }
+
+ private:
+ void clear_to_size(size_type new_num_buckets) {
+ if (!table) {
+ table = val_info.allocate(new_num_buckets);
+ } else {
+ destroy_buckets(0, num_buckets);
+ if (new_num_buckets != num_buckets) { // resize, if necessary
+ typedef base::integral_constant<bool,
+ base::is_same<value_alloc_type,
+ libc_allocator_with_realloc<value_type> >::value>
+ realloc_ok;
+ resize_table(num_buckets, new_num_buckets, realloc_ok());
+ }
+ }
+ assert(table);
+ fill_range_with_empty(table, table + new_num_buckets);
+ num_elements = 0;
+ num_deleted = 0;
+ num_buckets = new_num_buckets; // our new size
+ settings.reset_thresholds(bucket_count());
+ }
+
+ public:
+ // It's always nice to be able to clear a table without deallocating it
+ void clear() {
+ // If the table is already empty, and the number of buckets is
+ // already as we desire, there's nothing to do.
+ const size_type new_num_buckets = settings.min_buckets(0, 0);
+ if (num_elements == 0 && new_num_buckets == num_buckets) {
+ return;
+ }
+ clear_to_size(new_num_buckets);
+ }
+
+ // Clear the table without resizing it.
+ // Mimicks the stl_hashtable's behaviour when clear()-ing in that it
+ // does not modify the bucket count
+ void clear_no_resize() {
+ if (num_elements > 0) {
+ assert(table);
+ destroy_buckets(0, num_buckets);
+ fill_range_with_empty(table, table + num_buckets);
+ }
+ // don't consider to shrink before another erase()
+ settings.reset_thresholds(bucket_count());
+ num_elements = 0;
+ num_deleted = 0;
+ }
+
+ // LOOKUP ROUTINES
+ private:
+ // Returns a pair of positions: 1st where the object is, 2nd where
+ // it would go if you wanted to insert it. 1st is ILLEGAL_BUCKET
+ // if object is not found; 2nd is ILLEGAL_BUCKET if it is.
+ // Note: because of deletions where-to-insert is not trivial: it's the
+ // first deleted bucket we see, as long as we don't find the key later
+ std::pair<size_type, size_type> find_position(const key_type &key) const {
+ size_type num_probes = 0; // how many times we've probed
+ const size_type bucket_count_minus_one = bucket_count() - 1;
+ size_type bucknum = hash(key) & bucket_count_minus_one;
+ size_type insert_pos = ILLEGAL_BUCKET; // where we would insert
+ while ( 1 ) { // probe until something happens
+ if ( test_empty(bucknum) ) { // bucket is empty
+ if ( insert_pos == ILLEGAL_BUCKET ) // found no prior place to insert
+ return std::pair<size_type,size_type>(ILLEGAL_BUCKET, bucknum);
+ else
+ return std::pair<size_type,size_type>(ILLEGAL_BUCKET, insert_pos);
+
+ } else if ( test_deleted(bucknum) ) {// keep searching, but mark to insert
+ if ( insert_pos == ILLEGAL_BUCKET )
+ insert_pos = bucknum;
+
+ } else if ( equals(key, get_key(table[bucknum])) ) {
+ return std::pair<size_type,size_type>(bucknum, ILLEGAL_BUCKET);
+ }
+ ++num_probes; // we're doing another probe
+ bucknum = (bucknum + JUMP_(key, num_probes)) & bucket_count_minus_one;
+ assert(num_probes < bucket_count()
+ && "Hashtable is full: an error in key_equal<> or hash<>");
+ }
+ }
+
+ public:
+
+ iterator find(const key_type& key) {
+ if ( size() == 0 ) return end();
+ std::pair<size_type, size_type> pos = find_position(key);
+ if ( pos.first == ILLEGAL_BUCKET ) // alas, not there
+ return end();
+ else
+ return iterator(this, table + pos.first, table + num_buckets, false);
+ }
+
+ const_iterator find(const key_type& key) const {
+ if ( size() == 0 ) return end();
+ std::pair<size_type, size_type> pos = find_position(key);
+ if ( pos.first == ILLEGAL_BUCKET ) // alas, not there
+ return end();
+ else
+ return const_iterator(this, table + pos.first, table+num_buckets, false);
+ }
+
+ // This is a tr1 method: the bucket a given key is in, or what bucket
+ // it would be put in, if it were to be inserted. Shrug.
+ size_type bucket(const key_type& key) const {
+ std::pair<size_type, size_type> pos = find_position(key);
+ return pos.first == ILLEGAL_BUCKET ? pos.second : pos.first;
+ }
+
+ // Counts how many elements have key key. For maps, it's either 0 or 1.
+ size_type count(const key_type &key) const {
+ std::pair<size_type, size_type> pos = find_position(key);
+ return pos.first == ILLEGAL_BUCKET ? 0 : 1;
+ }
+
+ // Likewise, equal_range doesn't really make sense for us. Oh well.
+ std::pair<iterator,iterator> equal_range(const key_type& key) {
+ iterator pos = find(key); // either an iterator or end
+ if (pos == end()) {
+ return std::pair<iterator,iterator>(pos, pos);
+ } else {
+ const iterator startpos = pos++;
+ return std::pair<iterator,iterator>(startpos, pos);
+ }
+ }
+ std::pair<const_iterator,const_iterator> equal_range(const key_type& key)
+ const {
+ const_iterator pos = find(key); // either an iterator or end
+ if (pos == end()) {
+ return std::pair<const_iterator,const_iterator>(pos, pos);
+ } else {
+ const const_iterator startpos = pos++;
+ return std::pair<const_iterator,const_iterator>(startpos, pos);
+ }
+ }
+
+
+ // INSERTION ROUTINES
+ private:
+ // Private method used by insert_noresize and find_or_insert.
+ iterator insert_at(const_reference obj, size_type pos) {
+ if (size() >= max_size()) {
+ throw std::length_error("insert overflow");
+ }
+ if ( test_deleted(pos) ) { // just replace if it's been del.
+ // shrug: shouldn't need to be const.
+ const_iterator delpos(this, table + pos, table + num_buckets, false);
+ clear_deleted(delpos);
+ assert( num_deleted > 0);
+ --num_deleted; // used to be, now it isn't
+ } else {
+ ++num_elements; // replacing an empty bucket
+ }
+ set_value(&table[pos], obj);
+ return iterator(this, table + pos, table + num_buckets, false);
+ }
+
+ // If you know *this is big enough to hold obj, use this routine
+ std::pair<iterator, bool> insert_noresize(const_reference obj) {
+ // First, double-check we're not inserting delkey or emptyval
+ assert((!settings.use_empty() || !equals(get_key(obj),
+ get_key(val_info.emptyval)))
+ && "Inserting the empty key");
+ assert((!settings.use_deleted() || !equals(get_key(obj), key_info.delkey))
+ && "Inserting the deleted key");
+ const std::pair<size_type,size_type> pos = find_position(get_key(obj));
+ if ( pos.first != ILLEGAL_BUCKET) { // object was already there
+ return std::pair<iterator,bool>(iterator(this, table + pos.first,
+ table + num_buckets, false),
+ false); // false: we didn't insert
+ } else { // pos.second says where to put it
+ return std::pair<iterator,bool>(insert_at(obj, pos.second), true);
+ }
+ }
+
+ // Specializations of insert(it, it) depending on the power of the iterator:
+ // (1) Iterator supports operator-, resize before inserting
+ template <class ForwardIterator>
+ void insert(ForwardIterator f, ForwardIterator l, std::forward_iterator_tag) {
+ size_t dist = std::distance(f, l);
+ if (dist >= (std::numeric_limits<size_type>::max)()) {
+ throw std::length_error("insert-range overflow");
+ }
+ resize_delta(static_cast<size_type>(dist));
+ for ( ; dist > 0; --dist, ++f) {
+ insert_noresize(*f);
+ }
+ }
+
+ // (2) Arbitrary iterator, can't tell how much to resize
+ template <class InputIterator>
+ void insert(InputIterator f, InputIterator l, std::input_iterator_tag) {
+ for ( ; f != l; ++f)
+ insert(*f);
+ }
+
+ public:
+ // This is the normal insert routine, used by the outside world
+ std::pair<iterator, bool> insert(const_reference obj) {
+ resize_delta(1); // adding an object, grow if need be
+ return insert_noresize(obj);
+ }
+
+ // When inserting a lot at a time, we specialize on the type of iterator
+ template <class InputIterator>
+ void insert(InputIterator f, InputIterator l) {
+ // specializes on iterator type
+ insert(f, l,
+ typename std::iterator_traits<InputIterator>::iterator_category());
+ }
+
+ // DefaultValue is a functor that takes a key and returns a value_type
+ // representing the default value to be inserted if none is found.
+ template <class DefaultValue>
+ value_type& find_or_insert(const key_type& key) {
+ // First, double-check we're not inserting emptykey or delkey
+ assert((!settings.use_empty() || !equals(key, get_key(val_info.emptyval)))
+ && "Inserting the empty key");
+ assert((!settings.use_deleted() || !equals(key, key_info.delkey))
+ && "Inserting the deleted key");
+ const std::pair<size_type,size_type> pos = find_position(key);
+ DefaultValue default_value;
+ if ( pos.first != ILLEGAL_BUCKET) { // object was already there
+ return table[pos.first];
+ } else if (resize_delta(1)) { // needed to rehash to make room
+ // Since we resized, we can't use pos, so recalculate where to insert.
+ return *insert_noresize(default_value(key)).first;
+ } else { // no need to rehash, insert right here
+ return *insert_at(default_value(key), pos.second);
+ }
+ }
+
+
+ // DELETION ROUTINES
+ size_type erase(const key_type& key) {
+ // First, double-check we're not trying to erase delkey or emptyval.
+ assert((!settings.use_empty() || !equals(key, get_key(val_info.emptyval)))
+ && "Erasing the empty key");
+ assert((!settings.use_deleted() || !equals(key, key_info.delkey))
+ && "Erasing the deleted key");
+ const_iterator pos = find(key); // shrug: shouldn't need to be const
+ if ( pos != end() ) {
+ assert(!test_deleted(pos)); // or find() shouldn't have returned it
+ set_deleted(pos);
+ ++num_deleted;
+ settings.set_consider_shrink(true); // will think about shrink after next insert
+ return 1; // because we deleted one thing
+ } else {
+ return 0; // because we deleted nothing
+ }
+ }
+
+ // We return the iterator past the deleted item.
+ void erase(iterator pos) {
+ if ( pos == end() ) return; // sanity check
+ if ( set_deleted(pos) ) { // true if object has been newly deleted
+ ++num_deleted;
+ settings.set_consider_shrink(true); // will think about shrink after next insert
+ }
+ }
+
+ void erase(iterator f, iterator l) {
+ for ( ; f != l; ++f) {
+ if ( set_deleted(f) ) // should always be true
+ ++num_deleted;
+ }
+ settings.set_consider_shrink(true); // will think about shrink after next insert
+ }
+
+ // We allow you to erase a const_iterator just like we allow you to
+ // erase an iterator. This is in parallel to 'delete': you can delete
+ // a const pointer just like a non-const pointer. The logic is that
+ // you can't use the object after it's erased anyway, so it doesn't matter
+ // if it's const or not.
+ void erase(const_iterator pos) {
+ if ( pos == end() ) return; // sanity check
+ if ( set_deleted(pos) ) { // true if object has been newly deleted
+ ++num_deleted;
+ settings.set_consider_shrink(true); // will think about shrink after next insert
+ }
+ }
+ void erase(const_iterator f, const_iterator l) {
+ for ( ; f != l; ++f) {
+ if ( set_deleted(f) ) // should always be true
+ ++num_deleted;
+ }
+ settings.set_consider_shrink(true); // will think about shrink after next insert
+ }
+
+
+ // COMPARISON
+ bool operator==(const dense_hashtable& ht) const {
+ if (size() != ht.size()) {
+ return false;
+ } else if (this == &ht) {
+ return true;
+ } else {
+ // Iterate through the elements in "this" and see if the
+ // corresponding element is in ht
+ for ( const_iterator it = begin(); it != end(); ++it ) {
+ const_iterator it2 = ht.find(get_key(*it));
+ if ((it2 == ht.end()) || (*it != *it2)) {
+ return false;
+ }
+ }
+ return true;
+ }
+ }
+ bool operator!=(const dense_hashtable& ht) const {
+ return !(*this == ht);
+ }
+
+
+ // I/O
+ // We support reading and writing hashtables to disk. Alas, since
+ // I don't know how to write a hasher or key_equal, you have to make
+ // sure everything but the table is the same. We compact before writing.
+ private:
+ // Every time the disk format changes, this should probably change too
+ typedef unsigned long MagicNumberType;
+ static const MagicNumberType MAGIC_NUMBER = 0x13578642;
+
+ public:
+ // I/O -- this is an add-on for writing hash table to disk
+ //
+ // INPUT and OUTPUT must be either a FILE, *or* a C++ stream
+ // (istream, ostream, etc) *or* a class providing
+ // Read(void*, size_t) and Write(const void*, size_t)
+ // (respectively), which writes a buffer into a stream
+ // (which the INPUT/OUTPUT instance presumably owns).
+
+ typedef sparsehash_internal::pod_serializer<value_type> NopointerSerializer;
+
+ // ValueSerializer: a functor. operator()(OUTPUT*, const value_type&)
+ template <typename ValueSerializer, typename OUTPUT>
+ bool serialize(ValueSerializer serializer, OUTPUT *fp) {
+ squash_deleted(); // so we don't have to worry about delkey
+ if ( !sparsehash_internal::write_bigendian_number(fp, MAGIC_NUMBER, 4) )
+ return false;
+ if ( !sparsehash_internal::write_bigendian_number(fp, num_buckets, 8) )
+ return false;
+ if ( !sparsehash_internal::write_bigendian_number(fp, num_elements, 8) )
+ return false;
+ // Now write a bitmap of non-empty buckets.
+ for ( size_type i = 0; i < num_buckets; i += 8 ) {
+ unsigned char bits = 0;
+ for ( int bit = 0; bit < 8; ++bit ) {
+ if ( i + bit < num_buckets && !test_empty(i + bit) )
+ bits |= (1 << bit);
+ }
+ if ( !sparsehash_internal::write_data(fp, &bits, sizeof(bits)) )
+ return false;
+ for ( int bit = 0; bit < 8; ++bit ) {
+ if ( bits & (1 << bit) ) {
+ if ( !serializer(fp, table[i + bit]) ) return false;
+ }
+ }
+ }
+ return true;
+ }
+
+ // INPUT: anything we've written an overload of read_data() for.
+ // ValueSerializer: a functor. operator()(INPUT*, value_type*)
+ template <typename ValueSerializer, typename INPUT>
+ bool unserialize(ValueSerializer serializer, INPUT *fp) {
+ assert(settings.use_empty() && "empty_key not set for read");
+
+ clear(); // just to be consistent
+ MagicNumberType magic_read;
+ if ( !sparsehash_internal::read_bigendian_number(fp, &magic_read, 4) )
+ return false;
+ if ( magic_read != MAGIC_NUMBER ) {
+ return false;
+ }
+ size_type new_num_buckets;
+ if ( !sparsehash_internal::read_bigendian_number(fp, &new_num_buckets, 8) )
+ return false;
+ clear_to_size(new_num_buckets);
+ if ( !sparsehash_internal::read_bigendian_number(fp, &num_elements, 8) )
+ return false;
+
+ // Read the bitmap of non-empty buckets.
+ for (size_type i = 0; i < num_buckets; i += 8) {
+ unsigned char bits;
+ if ( !sparsehash_internal::read_data(fp, &bits, sizeof(bits)) )
+ return false;
+ for ( int bit = 0; bit < 8; ++bit ) {
+ if ( i + bit < num_buckets && (bits & (1 << bit)) ) { // not empty
+ if ( !serializer(fp, &table[i + bit]) ) return false;
+ }
+ }
+ }
+ return true;
+ }
+
+ private:
+ template <class A>
+ class alloc_impl : public A {
+ public:
+ typedef typename A::pointer pointer;
+ typedef typename A::size_type size_type;
+
+ // Convert a normal allocator to one that has realloc_or_die()
+ alloc_impl(const A& a) : A(a) { }
+
+ // realloc_or_die should only be used when using the default
+ // allocator (libc_allocator_with_realloc).
+ pointer realloc_or_die(pointer /*ptr*/, size_type /*n*/) {
+ fprintf(stderr, "realloc_or_die is only supported for "
+ "libc_allocator_with_realloc\n");
+ exit(1);
+ return NULL;
+ }
+ };
+
+ // A template specialization of alloc_impl for
+ // libc_allocator_with_realloc that can handle realloc_or_die.
+ template <class A>
+ class alloc_impl<libc_allocator_with_realloc<A> >
+ : public libc_allocator_with_realloc<A> {
+ public:
+ typedef typename libc_allocator_with_realloc<A>::pointer pointer;
+ typedef typename libc_allocator_with_realloc<A>::size_type size_type;
+
+ alloc_impl(const libc_allocator_with_realloc<A>& a)
+ : libc_allocator_with_realloc<A>(a) { }
+
+ pointer realloc_or_die(pointer ptr, size_type n) {
+ pointer retval = this->reallocate(ptr, n);
+ if (retval == NULL) {
+ fprintf(stderr, "sparsehash: FATAL ERROR: failed to reallocate "
+ "%lu elements for ptr %p", static_cast<unsigned long>(n), ptr);
+ exit(1);
+ }
+ return retval;
+ }
+ };
+
+ // Package allocator with emptyval to eliminate memory needed for
+ // the zero-size allocator.
+ // If new fields are added to this class, we should add them to
+ // operator= and swap.
+ class ValInfo : public alloc_impl<value_alloc_type> {
+ public:
+ typedef typename alloc_impl<value_alloc_type>::value_type value_type;
+
+ ValInfo(const alloc_impl<value_alloc_type>& a)
+ : alloc_impl<value_alloc_type>(a), emptyval() { }
+ ValInfo(const ValInfo& v)
+ : alloc_impl<value_alloc_type>(v), emptyval(v.emptyval) { }
+
+ value_type emptyval; // which key marks unused entries
+ };
+
+
+ // Package functors with another class to eliminate memory needed for
+ // zero-size functors. Since ExtractKey and hasher's operator() might
+ // have the same function signature, they must be packaged in
+ // different classes.
+ struct Settings :
+ sparsehash_internal::sh_hashtable_settings<key_type, hasher,
+ size_type, HT_MIN_BUCKETS> {
+ explicit Settings(const hasher& hf)
+ : sparsehash_internal::sh_hashtable_settings<key_type, hasher,
+ size_type, HT_MIN_BUCKETS>(
+ hf, HT_OCCUPANCY_PCT / 100.0f, HT_EMPTY_PCT / 100.0f) {}
+ };
+
+ // Packages ExtractKey and SetKey functors.
+ class KeyInfo : public ExtractKey, public SetKey, public EqualKey {
+ public:
+ KeyInfo(const ExtractKey& ek, const SetKey& sk, const EqualKey& eq)
+ : ExtractKey(ek),
+ SetKey(sk),
+ EqualKey(eq) {
+ }
+
+ // We want to return the exact same type as ExtractKey: Key or const Key&
+ typename ExtractKey::result_type get_key(const_reference v) const {
+ return ExtractKey::operator()(v);
+ }
+ void set_key(pointer v, const key_type& k) const {
+ SetKey::operator()(v, k);
+ }
+ bool equals(const key_type& a, const key_type& b) const {
+ return EqualKey::operator()(a, b);
+ }
+
+ // Which key marks deleted entries.
+ // TODO(csilvers): make a pointer, and get rid of use_deleted (benchmark!)
+ typename base::remove_const<key_type>::type delkey;
+ };
+
+ // Utility functions to access the templated operators
+ size_type hash(const key_type& v) const {
+ return settings.hash(v);
+ }
+ bool equals(const key_type& a, const key_type& b) const {
+ return key_info.equals(a, b);
+ }
+ typename ExtractKey::result_type get_key(const_reference v) const {
+ return key_info.get_key(v);
+ }
+ void set_key(pointer v, const key_type& k) const {
+ key_info.set_key(v, k);
+ }
+
+ private:
+ // Actual data
+ Settings settings;
+ KeyInfo key_info;
+
+ size_type num_deleted; // how many occupied buckets are marked deleted
+ size_type num_elements;
+ size_type num_buckets;
+ ValInfo val_info; // holds emptyval, and also the allocator
+ pointer table;
+};
+
+
+// We need a global swap as well
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+inline void swap(dense_hashtable<V,K,HF,ExK,SetK,EqK,A> &x,
+ dense_hashtable<V,K,HF,ExK,SetK,EqK,A> &y) {
+ x.swap(y);
+}
+
+#undef JUMP_
+
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+const typename dense_hashtable<V,K,HF,ExK,SetK,EqK,A>::size_type
+ dense_hashtable<V,K,HF,ExK,SetK,EqK,A>::ILLEGAL_BUCKET;
+
+// How full we let the table get before we resize. Knuth says .8 is
+// good -- higher causes us to probe too much, though saves memory.
+// However, we go with .5, getting better performance at the cost of
+// more space (a trade-off densehashtable explicitly chooses to make).
+// Feel free to play around with different values, though, via
+// max_load_factor() and/or set_resizing_parameters().
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+const int dense_hashtable<V,K,HF,ExK,SetK,EqK,A>::HT_OCCUPANCY_PCT = 50;
+
+// How empty we let the table get before we resize lower.
+// It should be less than OCCUPANCY_PCT / 2 or we thrash resizing.
+template <class V, class K, class HF, class ExK, class SetK, class EqK, class A>
+const int dense_hashtable<V,K,HF,ExK,SetK,EqK,A>::HT_EMPTY_PCT
+ = static_cast<int>(0.4 *
+ dense_hashtable<V,K,HF,ExK,SetK,EqK,A>::HT_OCCUPANCY_PCT);
+
+_END_GOOGLE_NAMESPACE_
+
+#endif /* _DENSEHASHTABLE_H_ */
View
381 deps/sparsehash/internal/hashtable-common.h
@@ -0,0 +1,381 @@
+// Copyright (c) 2010, 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.
+
+// ---
+//
+// Provides classes shared by both sparse and dense hashtable.
+//
+// sh_hashtable_settings has parameters for growing and shrinking
+// a hashtable. It also packages zero-size functor (ie. hasher).
+//
+// Other functions and classes provide common code for serializing
+// and deserializing hashtables to a stream (such as a FILE*).
+
+#ifndef UTIL_GTL_HASHTABLE_COMMON_H_
+#define UTIL_GTL_HASHTABLE_COMMON_H_
+
+#include <sparsehash/internal/sparseconfig.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stddef.h> // for size_t
+#include <iosfwd>
+#include <stdexcept> // For length_error
+
+_START_GOOGLE_NAMESPACE_
+
+template <bool> struct SparsehashCompileAssert { };
+#define SPARSEHASH_COMPILE_ASSERT(expr, msg) \
+ typedef SparsehashCompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
+
+namespace sparsehash_internal {
+
+// Adaptor methods for reading/writing data from an INPUT or OUPTUT
+// variable passed to serialize() or unserialize(). For now we
+// have implemented INPUT/OUTPUT for FILE*, istream*/ostream* (note
+// they are pointers, unlike typical use), or else a pointer to
+// something that supports a Read()/Write() method.
+//
+// For technical reasons, we implement read_data/write_data in two
+// stages. The actual work is done in *_data_internal, which takes
+// the stream argument twice: once as a template type, and once with
+// normal type information. (We only use the second version.) We do
+// this because of how C++ picks what function overload to use. If we
+// implemented this the naive way:
+// bool read_data(istream* is, const void* data, size_t length);
+// template<typename T> read_data(T* fp, const void* data, size_t length);
+// C++ would prefer the second version for every stream type except
+// istream. However, we want C++ to prefer the first version for
+// streams that are *subclasses* of istream, such as istringstream.
+// This is not possible given the way template types are resolved. So
+// we split the stream argument in two, one of which is templated and
+// one of which is not. The specialized functions (like the istream
+// version above) ignore the template arg and use the second, 'type'
+// arg, getting subclass matching as normal. The 'catch-all'
+// functions (the second version above) use the template arg to deduce
+// the type, and use a second, void* arg to achieve the desired
+// 'catch-all' semantics.
+
+// ----- low-level I/O for FILE* ----
+
+template<typename Ignored>
+inline bool read_data_internal(Ignored*, FILE* fp,
+ void* data, size_t length) {
+ return fread(data, length, 1, fp) == 1;
+}
+
+template<typename Ignored>
+inline bool write_data_internal(Ignored*, FILE* fp,
+ const void* data, size_t length) {
+ return fwrite(data, length, 1, fp) == 1;
+}
+
+// ----- low-level I/O for iostream ----
+
+// We want the caller to be responsible for #including <iostream>, not
+// us, because iostream is a big header! According to the standard,
+// it's only legal to delay the instantiation the way we want to if
+// the istream/ostream is a template type. So we jump through hoops.
+template<typename ISTREAM>
+inline bool read_data_internal_for_istream(ISTREAM* fp,
+ void* data, size_t length) {
+ return fp->read(reinterpret_cast<char*>(data), length).good();
+}
+template<typename Ignored>
+inline bool read_data_internal(Ignored*, std::istream* fp,
+ void* data, size_t length) {
+ return read_data_internal_for_istream(fp, data, length);
+}
+
+template<typename OSTREAM>
+inline bool write_data_internal_for_ostream(OSTREAM* fp,
+ const void* data, size_t length) {
+ return fp->write(reinterpret_cast<const char*>(data), length).good();
+}
+template<typename Ignored>
+inline bool write_data_internal(Ignored*, std::ostream* fp,
+ const void* data, size_t length) {
+ return write_data_internal_for_ostream(fp, data, length);
+}
+
+// ----- low-level I/O for custom streams ----
+
+// The INPUT type needs to support a Read() method that takes a
+// buffer and a length and returns the number of bytes read.
+template <typename INPUT>
+inline bool read_data_internal(INPUT* fp, void*,
+ void* data, size_t length) {
+ return static_cast<size_t>(fp->Read(data, length)) == length;
+}
+
+// The OUTPUT type needs to support a Write() operation that takes
+// a buffer and a length and returns the number of bytes written.
+template <typename OUTPUT>
+inline bool write_data_internal(OUTPUT* fp, void*,
+ const void* data, size_t length) {
+ return static_cast<size_t>(fp->Write(data, length)) == length;
+}
+
+// ----- low-level I/O: the public API ----
+
+template <typename INPUT>
+inline bool read_data(INPUT* fp, void* data, size_t length) {
+ return read_data_internal(fp, fp, data, length);
+}
+
+template <typename OUTPUT>
+inline bool write_data(OUTPUT* fp, const void* data, size_t length) {
+ return write_data_internal(fp, fp, data, length);
+}
+
+// Uses read_data() and write_data() to read/write an integer.
+// length is the number of bytes to read/write (which may differ
+// from sizeof(IntType), allowing us to save on a 32-bit system
+// and load on a 64-bit system). Excess bytes are taken to be 0.
+// INPUT and OUTPUT must match legal inputs to read/write_data (above).
+template <typename INPUT, typename IntType>
+bool read_bigendian_number(INPUT* fp, IntType* value, size_t length) {
+ *value = 0;
+ unsigned char byte;
+ // We require IntType to be unsigned or else the shifting gets all screwy.
+ SPARSEHASH_COMPILE_ASSERT(static_cast<IntType>(-1) > static_cast<IntType>(0),
+ serializing_int_requires_an_unsigned_type);
+ for (size_t i = 0; i < length; ++i) {
+ if (!read_data(fp, &byte, sizeof(byte))) return false;
+ *value |= static_cast<IntType>(byte) << ((length - 1 - i) * 8);
+ }
+ return true;
+}
+
+template <typename OUTPUT, typename IntType>
+bool write_bigendian_number(OUTPUT* fp, IntType value, size_t length) {
+ unsigned char byte;
+ // We require IntType to be unsigned or else the shifting gets all screwy.
+ SPARSEHASH_COMPILE_ASSERT(static_cast<IntType>(-1) > static_cast<IntType>(0),
+ serializing_int_requires_an_unsigned_type);
+ for (size_t i = 0; i < length; ++i) {
+ byte = (sizeof(value) <= length-1 - i)
+ ? 0 : static_cast<unsigned char>((value >> ((length-1 - i) * 8)) & 255);
+ if (!write_data(fp, &byte, sizeof(byte))) return false;
+ }
+ return true;
+}
+
+// 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.
+// This is the type used for NopointerSerializer.
+template <typename value_type> struct pod_serializer {
+ template <typename INPUT>
+ bool operator()(INPUT* fp, value_type* value) const {
+ return read_data(fp, value, sizeof(*value));
+ }
+
+ template <typename OUTPUT>
+ bool operator()(OUTPUT* fp, const value_type& value) const {
+ return write_data(fp, &value, sizeof(value));
+ }
+};
+
+
+// Settings contains parameters for growing and shrinking the table.
+// It also packages zero-size functor (ie. hasher).
+//
+// It does some munging of the hash value in cases where we think
+// (fear) the original hash function might not be very good. In
+// particular, the default hash of pointers is the identity hash,
+// so probably all the low bits are 0. We identify when we think
+// we're hashing a pointer, and chop off the low bits. Note this
+// isn't perfect: even when the key is a pointer, we can't tell
+// for sure that the hash is the identity hash. If it's not, this
+// is needless work (and possibly, though not likely, harmful).
+
+template<typename Key, typename HashFunc,
+ typename SizeType, int HT_MIN_BUCKETS>
+class sh_hashtable_settings : public HashFunc {
+ public:
+ typedef Key key_type;
+ typedef HashFunc hasher;
+ typedef SizeType size_type;
+
+ public:
+ sh_hashtable_settings(const hasher& hf,
+ const float ht_occupancy_flt,
+ const float ht_empty_flt)
+ : hasher(hf),
+ enlarge_threshold_(0),
+ shrink_threshold_(0),
+ consider_shrink_(false),
+ use_empty_(false),
+ use_deleted_(false),
+ num_ht_copies_(0) {
+ set_enlarge_factor(ht_occupancy_flt);
+ set_shrink_factor(ht_empty_flt);
+ }
+
+ size_type hash(const key_type& v) const {
+ // We munge the hash value when we don't trust hasher::operator().
+ return hash_munger<Key>::MungedHash(hasher::operator()(v));
+ }
+
+ float enlarge_factor() const {
+ return enlarge_factor_;
+ }
+ void set_enlarge_factor(float f) {
+ enlarge_factor_ = f;
+ }
+ float shrink_factor() const {
+ return shrink_factor_;
+ }
+ void set_shrink_factor(float f) {
+ shrink_factor_ = f;
+ }
+
+ size_type enlarge_threshold() const {
+ return enlarge_threshold_;
+ }
+ void set_enlarge_threshold(size_type t) {
+ enlarge_threshold_ = t;
+ }
+ size_type shrink_threshold() const {
+ return shrink_threshold_;
+ }
+ void set_shrink_threshold(size_type t) {
+ shrink_threshold_ = t;
+ }
+
+ size_type enlarge_size(size_type x) const {
+ return static_cast<size_type>(x * enlarge_factor_);
+ }
+ size_type shrink_size(size_type x) const {
+ return static_cast<size_type>(x * shrink_factor_);
+ }
+
+ bool consider_shrink() const {
+ return consider_shrink_;
+ }
+ void set_consider_shrink(bool t) {
+ consider_shrink_ = t;
+ }
+
+ bool use_empty() const {
+ return use_empty_;
+ }
+ void set_use_empty(bool t) {
+ use_empty_ = t;
+ }
+
+ bool use_deleted() const {
+ return use_deleted_;
+ }
+ void set_use_deleted(bool t) {
+ use_deleted_ = t;
+ }
+
+ size_type num_ht_copies() const {
+ return static_cast<size_type>(num_ht_copies_);
+ }
+ void inc_num_ht_copies() {
+ ++num_ht_copies_;
+ }
+
+ // Reset the enlarge and shrink thresholds
+ void reset_thresholds(size_type num_buckets) {
+ set_enlarge_threshold(enlarge_size(num_buckets));
+ set_shrink_threshold(shrink_size(num_buckets));
+ // whatever caused us to reset already considered
+ set_consider_shrink(false);
+ }
+
+ // Caller is resposible for calling reset_threshold right after
+ // set_resizing_parameters.
+ void set_resizing_parameters(float shrink, float grow) {
+ assert(shrink >= 0.0);
+ assert(grow <= 1.0);
+ if (shrink > grow/2.0f)
+ shrink = grow / 2.0f; // otherwise we thrash hashtable size
+ set_shrink_factor(shrink);
+ set_enlarge_factor(grow);
+ }
+
+ // This is the smallest size a hashtable can be without being too crowded
+ // If you like, you can give a min #buckets as well as a min #elts
+ size_type min_buckets(size_type num_elts, size_type min_buckets_wanted) {
+ float enlarge = enlarge_factor();
+ size_type sz = HT_MIN_BUCKETS; // min buckets allowed
+ while ( sz < min_buckets_wanted ||
+ num_elts >= static_cast<size_type>(sz * enlarge) ) {
+ // This just prevents overflowing size_type, since sz can exceed
+ // max_size() here.
+ if (static_cast<size_type>(sz * 2) < sz) {
+ throw std::length_error("resize overflow"); // protect against overflow
+ }
+ sz *= 2;
+ }
+ return sz;
+ }
+
+ private:
+ template<class HashKey> class hash_munger {
+ public:
+ static size_t MungedHash(size_t hash) {
+ return hash;
+ }
+ };
+ // This matches when the hashtable key is a pointer.
+ template<class HashKey> class hash_munger<HashKey*> {
+ public:
+ static size_t MungedHash(size_t hash) {
+ // TODO(csilvers): consider rotating instead:
+ // static const int shift = (sizeof(void *) == 4) ? 2 : 3;
+ // return (hash << (sizeof(hash) * 8) - shift)) | (hash >> shift);
+ // This matters if we ever change sparse/dense_hash_* to compare
+ // hashes before comparing actual values. It's speedy on x86.
+ return hash / sizeof(void*); // get rid of known-0 bits
+ }
+ };
+
+ size_type enlarge_threshold_; // table.size() * enlarge_factor
+ size_type shrink_threshold_; // table.size() * shrink_factor
+ float enlarge_factor_; // how full before resize
+ float shrink_factor_; // how empty before resize
+ // consider_shrink=true if we should try to shrink before next insert
+ bool consider_shrink_;
+ bool use_empty_; // used only by densehashtable, not sparsehashtable
+ bool use_deleted_; // false until delkey has been set
+ // num_ht_copies is a counter incremented every Copy/Move
+ unsigned int num_ht_copies_;
+};
+
+} // namespace sparsehash_internal
+
+#undef SPARSEHASH_COMPILE_ASSERT
+_END_GOOGLE_NAMESPACE_
+
+#endif // UTIL_GTL_HASHTABLE_COMMON_H_
View
119 deps/sparsehash/internal/libc_allocator_with_realloc.h
@@ -0,0 +1,119 @@
+// Copyright (c) 2010, 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.
+
+// ---
+
+#ifndef UTIL_GTL_LIBC_ALLOCATOR_WITH_REALLOC_H_
+#define UTIL_GTL_LIBC_ALLOCATOR_WITH_REALLOC_H_
+
+#include <sparsehash/internal/sparseconfig.h>
+#include <stdlib.h> // for malloc/realloc/free
+#include <stddef.h> // for ptrdiff_t
+#include <new> // for placement new
+
+_START_GOOGLE_NAMESPACE_
+
+template<class T>
+class libc_allocator_with_realloc {
+ public:
+ typedef T value_type;
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+
+ typedef T* pointer;
+ typedef const T* const_pointer;
+ typedef T& reference;
+ typedef const T& const_reference;
+
+ libc_allocator_with_realloc() {}
+ libc_allocator_with_realloc(const libc_allocator_with_realloc&) {}
+ ~libc_allocator_with_realloc() {}
+
+ pointer address(reference r) const { return &r; }
+ const_pointer address(const_reference r) const { return &r; }
+
+ pointer allocate(size_type n, const_pointer = 0) {
+ return static_cast<pointer>(malloc(n * sizeof(value_type)));
+ }
+ void deallocate(pointer p, size_type) {
+ free(p);
+ }
+ pointer reallocate(pointer p, size_type n) {
+ return static_cast<pointer>(realloc(p, n * sizeof(value_type)));
+ }
+
+ size_type max_size() const {
+ return static_cast<size_type>(-1) / sizeof(value_type);
+ }
+
+ void construct(pointer p, const value_type& val) {
+ new(p) value_type(val);
+ }
+ void destroy(pointer p) { p->~value_type(); }
+
+ template <class U>
+ libc_allocator_with_realloc(const libc_allocator_with_realloc<U>&) {}
+
+ template<class U>
+ struct rebind {
+ typedef libc_allocator_with_realloc<U> other;
+ };
+};
+
+// libc_allocator_with_realloc<void> specialization.
+template<>
+class libc_allocator_with_realloc<void> {
+ public:
+ typedef void value_type;
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+ typedef void* pointer;
+ typedef const void* const_pointer;
+
+ template<class U>
+ struct rebind {
+ typedef libc_allocator_with_realloc<U> other;
+ };
+};
+
+template<class T>
+inline bool operator==(const libc_allocator_with_realloc<T>&,
+ const libc_allocator_with_realloc<T>&) {
+ return true;
+}
+
+template<class T>
+inline bool operator!=(const libc_allocator_with_realloc<T>&,
+ const libc_allocator_with_realloc<T>&) {
+ return false;
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#endif // UTIL_GTL_LIBC_ALLOCATOR_WITH_REALLOC_H_
View
46 deps/sparsehash/internal/sparseconfig.h
@@ -0,0 +1,46 @@
+/*
+ * NOTE: This file is for internal use only.
+ * Do not use these #defines in your own program!
+ */
+
+/* Namespace for Google classes */
+#define GOOGLE_NAMESPACE ::google
+
+/* the location of the header defining hash functions */
+#define HASH_FUN_H <tr1/functional>
+
+/* the namespace of the hash<> function */
+#define HASH_NAMESPACE std::tr1
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define HAVE_INTTYPES_H 1
+
+/* Define to 1 if the system has the type `long long'. */
+#define HAVE_LONG_LONG 1
+
+/* Define to 1 if you have the `memcpy' function. */
+#define HAVE_MEMCPY 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if the system has the type `uint16_t'. */
+#define HAVE_UINT16_T 1
+
+/* Define to 1 if the system has the type `u_int16_t'. */
+#define HAVE_U_INT16_T 1
+
+/* Define to 1 if the system has the type `__uint16'. */
+/* #undef HAVE___UINT16 */
+
+/* The system-provided hash function including the namespace. */
+#define SPARSEHASH_HASH HASH_NAMESPACE::hash
+
+/* Stops putting the code inside the Google namespace */
+#define _END_GOOGLE_NAMESPACE_ }
+
+/* Puts following code inside the Google namespace */
+#define _START_GOOGLE_NAMESPACE_ namespace google {
View
134 deps/sparsehash/template_util.h
@@ -0,0 +1,134 @@
+// Copyright 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.
+
+// ----
+//
+// Template metaprogramming utility functions.
+//
+// This code is compiled directly on many platforms, including client
+// platforms like Windows, Mac, and embedded systems. Before making
+// any changes here, make sure that you're not breaking any platforms.
+//
+//
+// The names choosen here reflect those used in tr1 and the boost::mpl
+// library, there are similar operations used in the Loki library as
+// well. I prefer the boost names for 2 reasons:
+// 1. I think that portions of the Boost libraries are more likely to
+// be included in the c++ standard.
+// 2. It is not impossible that some of the boost libraries will be
+// included in our own build in the future.
+// Both of these outcomes means that we may be able to directly replace
+// some of these with boost equivalents.
+//
+#ifndef BASE_TEMPLATE_UTIL_H_
+#define BASE_TEMPLATE_UTIL_H_
+
+#include <sparsehash/internal/sparseconfig.h>
+_START_GOOGLE_NAMESPACE_
+
+// Types small_ and big_ are guaranteed such that sizeof(small_) <
+// sizeof(big_)
+typedef char small_;
+
+struct big_ {
+ char dummy[2];
+};
+
+// Identity metafunction.
+template <class T>
+struct identity_ {
+ typedef T type;
+};
+
+// integral_constant, defined in tr1, is a wrapper for an integer
+// value. We don't really need this generality; we could get away
+// with hardcoding the integer type to bool. We use the fully
+// general integer_constant for compatibility with tr1.
+
+template<class T, T v>
+struct integral_constant {
+ static const T value = v;
+ typedef T value_type;
+ typedef integral_constant<T, v> type;
+};
+
+template <class T, T v> const T integral_constant<T, v>::value;
+
+
+// Abbreviations: true_type and false_type are structs that represent boolean
+// true and false values. Also define the boost::mpl versions of those names,
+// true_ and false_.
+typedef integral_constant<bool, true> true_type;
+typedef integral_constant<bool, false> false_type;
+typedef true_type true_;
+typedef false_type false_;
+
+// if_ is a templatized conditional statement.
+// if_<cond, A, B> is a compile time evaluation of cond.
+// if_<>::type contains A if cond is true, B otherwise.
+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;
+};
+
+
+// type_equals_ is a template type comparator, similar to Loki IsSameType.
+// type_equals_<A, B>::value is true iff "A" is the same type as "B".
+//
+// New code should prefer base::is_same, defined in base/type_traits.h.
+// It is functionally identical, but is_same is the standard spelling.
+template<typename A, typename B>
+struct type_equals_ : public false_ {
+};
+
+template<typename A>
+struct type_equals_<A, A> : public true_ {
+};
+
+// and_ is a template && operator.
+// and_<A, B>::value evaluates "A::value && B::value".
+template<typename A, typename B>
+struct and_ : public integral_constant<bool, (A::value && B::value)> {
+};
+
+// or_ is a template || operator.
+// or_<A, B>::value evaluates "A::value || B::value".
+template<typename A, typename B>
+struct or_ : public integral_constant<bool, (A::value || B::value)> {
+};
+
+
+_END_GOOGLE_NAMESPACE_
+
+#endif // BASE_TEMPLATE_UTIL_H_
View
342 deps/sparsehash/type_traits.h
@@ -0,0 +1,342 @@
+// Copyright (c) 2006, 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 code is compiled directly on many platforms, including client
+// platforms like Windows, Mac, and embedded systems. Before making
+// any changes here, make sure that you're not breaking any platforms.
+//
+// Define a small subset of tr1 type traits. The traits we define are:
+// is_integral
+// is_floating_point
+// is_pointer
+// is_enum
+// is_reference
+// is_pod
+// has_trivial_constructor
+// has_trivial_copy
+// has_trivial_assign
+// has_trivial_destructor
+// remove_const
+// remove_volatile
+// remove_cv
+// remove_reference
+// add_reference
+// remove_pointer
+// is_same
+// is_convertible
+// We can add more type traits as required.
+
+#ifndef BASE_TYPE_TRAITS_H_
+#define BASE_TYPE_TRAITS_H_
+
+#include <sparsehash/internal/sparseconfig.h>
+#include <utility> // For pair
+
+#include <sparsehash/template_util.h> // For true_type and false_type
+
+_START_GOOGLE_NAMESPACE_
+
+template <class T> struct is_integral;
+template <class T> struct is_floating_point;
+template <class T> struct is_pointer;
+// MSVC can't compile this correctly, and neither can gcc 3.3.5 (at least)
+#if !defined(_MSC_VER) && !(defined(__GNUC__) && __GNUC__ <= 3)
+// is_enum uses is_convertible, which is not available on MSVC.
+template <class T> struct is_enum;
+#endif
+template <class T> struct is_reference;
+template <class T> struct is_pod;
+template <class T> struct has_trivial_constructor;
+template <class T> struct has_trivial_copy;
+template <class T> struct has_trivial_assign;
+template <class T> struct has_trivial_destructor;
+template <class T> struct remove_const;
+template <class T> struct remove_volatile;
+template <class T> struct remove_cv;
+template <class T> struct remove_reference;
+template <class T> struct add_reference;
+template <class T> struct remove_pointer;
+template <class T, class U> struct is_same;
+#if !defined(_MSC_VER) && !(defined(__GNUC__) && __GNUC__ <= 3)
+template <class From, class To> struct is_convertible;
+#endif
+
+// is_integral is false except for the built-in integer types. A
+// cv-qualified type is integral if and only if the underlying type is.
+template <class T> struct is_integral : false_type { };
+template<> struct is_integral<bool> : true_type { };
+template<> struct is_integral<char> : true_type { };
+template<> struct is_integral<unsigned char> : true_type { };
+template<> struct is_integral<signed char> : true_type { };
+#if defined(_MSC_VER)
+// wchar_t is not by default a distinct type from unsigned short in
+// Microsoft C.
+// See http://msdn2.microsoft.com/en-us/library/dh8che7s(VS.80).aspx
+template<> struct is_integral<__wchar_t> : true_type { };
+#else
+template<> struct is_integral<wchar_t> : true_type { };
+#endif
+template<> struct is_integral<short> : true_type { };
+template<> struct is_integral<unsigned short> : true_type { };
+template<> struct is_integral<int> : true_type { };
+template<> struct is_integral<unsigned int> : true_type { };
+template<> struct is_integral<long> : true_type { };
+template<> struct is_integral<unsigned long> : true_type { };
+#ifdef HAVE_LONG_LONG
+template<> struct is_integral<long long> : true_type { };
+template<> struct is_integral<unsigned long long> : true_type { };
+#endif
+template <class T> struct is_integral<const T> : is_integral<T> { };
+template <class T> struct is_integral<volatile T> : is_integral<T> { };
+template <class T> struct is_integral<const volatile T> : is_integral<T> { };
+
+// is_floating_point is false except for the built-in floating-point types.
+// A cv-qualified type is integral if and only if the underlying type is.
+template <class T> struct is_floating_point : false_type { };
+template<> struct is_floating_point<float> : true_type { };
+template<> struct is_floating_point<double> : true_type { };
+template<> struct is_floating_point<long double> : true_type { };
+template <class T> struct is_floating_point<const T>
+ : is_floating_point<T> { };
+template <class T> struct is_floating_point<volatile T>
+ : is_floating_point<T> { };
+template <class T> struct is_floating_point<const volatile T>
+ : is_floating_point<T> { };
+
+// is_pointer i