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gcc/libstdc++-v3/include/tr1/hashtable
Paolo Carlini 909a9d44ff functional: Fix License to GPL with exception. 
2005-02-22  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/functional: Fix License to GPL with exception.
	* include/tr1/hashtable: Likewise.
	* include/tr1/tuple: Likewise.
	* include/tr1/type_traits: Likewise.
	* include/tr1/type_traits_fwd.h: Likewise.
	* include/tr1/unordered_map: Likewise.
	* include/tr1/unordered_set: Likewise.
	* include/tr1/utility: Likewise.

From-SVN: r95398
2005-02-22 17:07:07 +00:00

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// Internal header for TR1 unordered_set and unordered_map -*- C++ -*-
// Copyright (C) 2005 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING. If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.
// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License. This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
/** @file
* This is a TR1 C++ Library header.
*/
// This header file defines std::tr1::hashtable, which is used to
// implement std::tr1::unordered_set, std::tr1::unordered_map,
// std::tr1::unordered_multiset, and std::tr1::unordered_multimap.
// hashtable has many template parameters, partly to accommodate
// the differences between those four classes and partly to
// accommodate policy choices that go beyond what TR1 calls for.
// ??? Arguably this should be Internal::hashtable, not std::tr1::hashtable.
// Class template hashtable attempts to encapsulate all reasonable
// variation among hash tables that use chaining. It does not handle
// open addressing.
// References:
// M. Austern, "A Proposal to Add Hash Tables to the Standard
// Library (revision 4)," WG21 Document N1456=03-0039, 2003.
// D. E. Knuth, The Art of Computer Programming, v. 3, Sorting and Searching.
// A. Tavori and V. Dreizin, "Generic Associative Containers", 2004.
// ??? Full citation?
#ifndef GNU_LIBSTDCXX_TR1_HASHTABLE_
#define GNU_LIBSTDCXX_TR1_HASHTABLE_
#include <utility> // For std::pair
#include <iterator>
#include <cstddef>
#include <cstdlib>
#include <cmath>
#include <tr1/type_traits> // For true_type and false_type
//----------------------------------------------------------------------
// General utilities
namespace Internal {
template <bool Flag, typename IfTrue, typename IfFalse> struct IF;
template <typename IfTrue, typename IfFalse>
struct IF <true, IfTrue, IfFalse> { typedef IfTrue type; };
template <typename IfTrue, typename IfFalse>
struct IF <false, IfTrue, IfFalse> { typedef IfFalse type; };
// Helper function: return distance(first, last) for forward
// iterators, or 0 for input iterators.
template <class Iterator>
inline typename std::iterator_traits<Iterator>::difference_type
distance_fw (Iterator first, Iterator last, std::input_iterator_tag)
{
return 0;
}
template <class Iterator>
inline typename std::iterator_traits<Iterator>::difference_type
distance_fw (Iterator first, Iterator last, std::forward_iterator_tag)
{
return std::distance(first, last);
}
template <class Iterator>
inline typename std::iterator_traits<Iterator>::difference_type
distance_fw (Iterator first, Iterator last)
{
typedef typename std::iterator_traits<Iterator>::iterator_category tag;
return distance_fw(first, last, tag());
}
} // namespace Internal
//----------------------------------------------------------------------
// Auxiliary types used for all instantiations of hashtable: nodes
// and iterators.
// Nodes, used to wrap elements stored in the hash table. A policy
// template parameter of class template hashtable controls whether
// nodes also store a hash code. In some cases (e.g. strings) this may
// be a performance win.
namespace Internal {
template <typename Value, bool cache_hash_code> struct hash_node;
template <typename Value>
struct hash_node<Value, true> {
Value m_v;
std::size_t hash_code;
hash_node* m_next;
};
template <typename Value>
struct hash_node<Value, false> {
Value m_v;
hash_node* m_next;
};
// Local iterators, used to iterate within a bucket but not between
// buckets.
template <typename Value, bool cache>
struct node_iterator_base {
node_iterator_base(hash_node<Value, cache>* p) : m_cur(p) { }
void incr() { m_cur = m_cur->m_next; }
hash_node<Value, cache>* m_cur;
};
template <typename Value, bool cache>
inline bool operator== (const node_iterator_base<Value, cache>& x,
const node_iterator_base<Value, cache>& y)
{
return x.m_cur == y.m_cur;
}
template <typename Value, bool cache>
inline bool operator!= (const node_iterator_base<Value, cache>& x,
const node_iterator_base<Value, cache>& y)
{
return x.m_cur != y.m_cur;
}
template <typename Value, bool is_const, bool cache>
struct node_iterator : public node_iterator_base<Value, cache> {
typedef Value value_type;
typedef typename IF<is_const, const Value*, Value*>::type pointer;
typedef typename IF<is_const, const Value&, Value&>::type reference;
typedef std::ptrdiff_t difference_type;
typedef std::forward_iterator_tag iterator_category;
explicit node_iterator (hash_node<Value, cache>* p = 0)
: node_iterator_base<Value, cache>(p) { }
node_iterator (const node_iterator<Value, true, cache>& x)
: node_iterator_base<Value, cache>(x.m_cur) { }
reference operator*() const { return this->m_cur->m_v; }
pointer operator->() const { return &this->m_cur->m_v; }
node_iterator& operator++() { this->incr(); return *this; }
node_iterator operator++(int)
{ node_iterator tmp(*this); this->incr(); return tmp; }
};
template <typename Value, bool cache>
struct hashtable_iterator_base {
hashtable_iterator_base(hash_node<Value, cache>* node,
hash_node<Value, cache>** bucket)
: m_cur_node (node), m_cur_bucket (bucket)
{ }
void incr() {
m_cur_node = m_cur_node->m_next;
if (!m_cur_node)
m_incr_bucket();
}
void m_incr_bucket();
hash_node<Value, cache>* m_cur_node;
hash_node<Value, cache>** m_cur_bucket;
};
// Global iterators, used for arbitrary iteration within a hash
// table. Larger and more expensive than local iterators.
template <typename Value, bool cache>
void hashtable_iterator_base<Value, cache>::m_incr_bucket()
{
++m_cur_bucket;
// This loop requires the bucket array to have a non-null sentinel
while (!*m_cur_bucket)
++m_cur_bucket;
m_cur_node = *m_cur_bucket;
}
template <typename Value, bool cache>
inline bool operator== (const hashtable_iterator_base<Value, cache>& x,
const hashtable_iterator_base<Value, cache>& y)
{
return x.m_cur_node == y.m_cur_node;
}
template <typename Value, bool cache>
inline bool operator!= (const hashtable_iterator_base<Value, cache>& x,
const hashtable_iterator_base<Value, cache>& y)
{
return x.m_cur_node != y.m_cur_node;
}
template <typename Value, bool is_const, bool cache>
struct hashtable_iterator : public hashtable_iterator_base<Value, cache>
{
typedef Value value_type;
typedef typename IF<is_const, const Value*, Value*>::type pointer;
typedef typename IF<is_const, const Value&, Value&>::type reference;
typedef std::ptrdiff_t difference_type;
typedef std::forward_iterator_tag iterator_category;
hashtable_iterator (hash_node<Value, cache>* p, hash_node<Value, cache>** b)
: hashtable_iterator_base<Value, cache>(p, b) { }
hashtable_iterator (hash_node<Value, cache>** b)
: hashtable_iterator_base<Value, cache>(*b, b) { }
hashtable_iterator (const hashtable_iterator<Value, true, cache>& x)
: hashtable_iterator_base<Value, cache>(x.m_cur_node, x.m_cur_bucket) { }
reference operator*() const { return this->m_cur_node->m_v; }
pointer operator->() const { return &this->m_cur_node->m_v; }
hashtable_iterator& operator++() { this->incr(); return *this; }
hashtable_iterator operator++(int)
{ hashtable_iterator tmp(*this); this->incr(); return tmp; }
};
} // namespace Internal
// ----------------------------------------------------------------------
// Many of class template hashtable's template parameters are policy
// classes. These are defaults for the policies.
namespace Internal {
// The two key extraction policies used by the *set and *map variants.
template <typename T>
struct identity {
T operator()(const T& t) const { return t; }
};
template <typename Pair>
struct extract1st {
typename Pair::first_type operator()(const Pair& p) const { return p.first; }
};
// Default range hashing function: use division to fold a large number
// into the range [0, N).
struct mod_range_hashing
{
typedef std::size_t first_argument_type;
typedef std::size_t second_argument_type;
typedef std::size_t result_type;
result_type operator() (first_argument_type r, second_argument_type N) const
{ return r % N; }
};
// Default ranged hash function H. In principle it should be a
// function object composed from objects of type H1 and H2 such that
// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
// h1 and h2. So instead we'll just use a tag to tell class template
// hashtable to do that composition.
struct default_ranged_hash { };
// Default value for rehash policy. Bucket size is (usually) the
// smallest prime that keeps the load factor small enough.
struct prime_rehash_policy
{
prime_rehash_policy (float z = 1.0);
float max_load_factor() const;
// Return a bucket size no smaller than n.
std::size_t next_bkt (std::size_t n) const;
// Return a bucket count appropriate for n elements
std::size_t bkt_for_elements (std::size_t n) const;
// n_bkt is current bucket count, n_elt is current element count,
// and n_ins is number of elements to be inserted. Do we need to
// increase bucket count? If so, return make_pair(true, n), where n
// is the new bucket count. If not, return make_pair(false, 0).
std::pair<bool, std::size_t>
need_rehash (std::size_t n_bkt, std::size_t n_elt, std::size_t n_ins) const;
float m_max_load_factor;
float m_growth_factor;
mutable std::size_t m_next_resize;
};
// XXX This is a hack. prime_rehash_policy's member functions, and
// certainly the list of primes, should be defined in a .cc file.
// We're temporarily putting them in a header because we don't have a
// place to put TR1 .cc files yet. There's no good reason for any of
// prime_rehash_policy's member functions to be inline, and there's
// certainly no good reason for X<> to exist at all.
struct lt {
template <typename X, typename Y> bool operator()(X x, Y y) { return x < y; }
};
template <int dummy>
struct X {
static const int n_primes = 256;
static const unsigned long primes[n_primes + 1];
};
template <int dummy>
const int X<dummy>::n_primes;
template <int dummy>
const unsigned long X<dummy>::primes[n_primes + 1] =
{
2ul, 3ul, 5ul, 7ul, 11ul, 13ul, 17ul, 19ul, 23ul, 29ul, 31ul,
37ul, 41ul, 43ul, 47ul, 53ul, 59ul, 61ul, 67ul, 71ul, 73ul, 79ul,
83ul, 89ul, 97ul, 103ul, 109ul, 113ul, 127ul, 137ul, 139ul, 149ul,
157ul, 167ul, 179ul, 193ul, 199ul, 211ul, 227ul, 241ul, 257ul,
277ul, 293ul, 313ul, 337ul, 359ul, 383ul, 409ul, 439ul, 467ul,
503ul, 541ul, 577ul, 619ul, 661ul, 709ul, 761ul, 823ul, 887ul,
953ul, 1031ul, 1109ul, 1193ul, 1289ul, 1381ul, 1493ul, 1613ul,
1741ul, 1879ul, 2029ul, 2179ul, 2357ul, 2549ul, 2753ul, 2971ul,
3209ul, 3469ul, 3739ul, 4027ul, 4349ul, 4703ul, 5087ul, 5503ul,
5953ul, 6427ul, 6949ul, 7517ul, 8123ul, 8783ul, 9497ul, 10273ul,
11113ul, 12011ul, 12983ul, 14033ul, 15173ul, 16411ul, 17749ul,
19183ul, 20753ul, 22447ul, 24281ul, 26267ul, 28411ul, 30727ul,
33223ul, 35933ul, 38873ul, 42043ul, 45481ul, 49201ul, 53201ul,
57557ul, 62233ul, 67307ul, 72817ul, 78779ul, 85229ul, 92203ul,
99733ul, 107897ul, 116731ul, 126271ul, 136607ul, 147793ul,
159871ul, 172933ul, 187091ul, 202409ul, 218971ul, 236897ul,
256279ul, 277261ul, 299951ul, 324503ul, 351061ul, 379787ul,
410857ul, 444487ul, 480881ul, 520241ul, 562841ul, 608903ul,
658753ul, 712697ul, 771049ul, 834181ul, 902483ul, 976369ul,
1056323ul, 1142821ul, 1236397ul, 1337629ul, 1447153ul, 1565659ul,
1693859ul, 1832561ul, 1982627ul, 2144977ul, 2320627ul, 2510653ul,
2716249ul, 2938679ul, 3179303ul, 3439651ul, 3721303ul, 4026031ul,
4355707ul, 4712381ul, 5098259ul, 5515729ul, 5967347ul, 6456007ul,
6984629ul, 7556579ul, 8175383ul, 8844859ul, 9569143ul, 10352717ul,
11200489ul, 12117689ul, 13109983ul, 14183539ul, 15345007ul,
16601593ul, 17961079ul, 19431899ul, 21023161ul, 22744717ul,
24607243ul, 26622317ul, 28802401ul, 31160981ul, 33712729ul,
36473443ul, 39460231ul, 42691603ul, 46187573ul, 49969847ul,
54061849ul, 58488943ul, 63278561ul, 68460391ul, 74066549ul,
80131819ul, 86693767ul, 93793069ul, 101473717ul, 109783337ul,
118773397ul, 128499677ul, 139022417ul, 150406843ul, 162723577ul,
176048909ul, 190465427ul, 206062531ul, 222936881ul, 241193053ul,
260944219ul, 282312799ul, 305431229ul, 330442829ul, 357502601ul,
386778277ul, 418451333ul, 452718089ul, 489790921ul, 529899637ul,
573292817ul, 620239453ul, 671030513ul, 725980837ul, 785430967ul,
849749479ul, 919334987ul, 994618837ul, 1076067617ul, 1164186217ul,
1259520799ul, 1362662261ul, 1474249943ul, 1594975441ul,
1725587117ul, 1866894511ul, 2019773507ul, 2185171673ul,
2364114217ul, 2557710269ul, 2767159799ul, 2993761039ul,
3238918481ul, 3504151727ul, 3791104843ul, 4101556399ul,
4294967291ul,
4294967291ul // sentinel so we don't have to test result of lower_bound
};
inline prime_rehash_policy::prime_rehash_policy (float z)
: m_max_load_factor(z),
m_growth_factor (2.f),
m_next_resize (0)
{ }
inline float prime_rehash_policy::max_load_factor() const
{
return m_max_load_factor;
}
// Return a prime no smaller than n.
inline std::size_t prime_rehash_policy::next_bkt (std::size_t n) const
{
const unsigned long* const last = X<0>::primes + X<0>::n_primes;
const unsigned long* p = std::lower_bound (X<0>::primes, last, n);
m_next_resize = static_cast<std::size_t>(std::ceil(*p * m_max_load_factor));
return *p;
}
// Return the smallest prime p such that alpha p >= n, where alpha
// is the load factor.
inline std::size_t prime_rehash_policy::bkt_for_elements (std::size_t n) const
{
const unsigned long* const last = X<0>::primes + X<0>::n_primes;
const float min_bkts = n / m_max_load_factor;
const unsigned long* p = std::lower_bound (X<0>::primes, last, min_bkts, lt());
m_next_resize = static_cast<std::size_t>(std::ceil(*p * m_max_load_factor));
return *p;
}
// Finds the smallest prime p such that alpha p > n_elt + n_ins.
// If p > n_bkt, return make_pair(true, p); otherwise return
// make_pair(false, 0). In principle this isn't very different from
// bkt_for_elements.
// The only tricky part is that we're caching the element count at
// which we need to rehash, so we don't have to do a floating-point
// multiply for every insertion.
inline std::pair<bool, std::size_t>
prime_rehash_policy
::need_rehash (std::size_t n_bkt, std::size_t n_elt, std::size_t n_ins) const
{
if (n_elt + n_ins > m_next_resize) {
float min_bkts = (float(n_ins) + float(n_elt)) / m_max_load_factor;
if (min_bkts > n_bkt) {
min_bkts = std::max (min_bkts, m_growth_factor * n_bkt);
const unsigned long* const last = X<0>::primes + X<0>::n_primes;
const unsigned long* p = std::lower_bound (X<0>::primes, last, min_bkts, lt());
m_next_resize = static_cast<std::size_t>(std::ceil(*p * m_max_load_factor));
return std::make_pair(true, *p);
}
else {
m_next_resize = static_cast<std::size_t>(std::ceil(n_bkt * m_max_load_factor));
return std::make_pair(false, 0);
}
}
else
return std::make_pair(false, 0);
}
} // namespace Internal
//----------------------------------------------------------------------
// Base classes for std::tr1::hashtable. We define these base classes
// because in some cases we want to do different things depending on
// the value of a policy class. In some cases the policy class affects
// which member functions and nested typedefs are defined; we handle that
// by specializing base class templates. Several of the base class templates
// need to access other members of class template hashtable, so we use
// the "curiously recurring template pattern" for them.
namespace Internal {
// class template map_base. If the hashtable has a value type of the
// form pair<T1, T2> and a key extraction policy that returns the
// first part of the pair, the hashtable gets a mapped_type typedef.
// If it satisfies those criteria and also has unique keys, then it
// also gets an operator[].
template <typename K, typename V, typename Ex, bool unique, typename Hashtable>
struct map_base { };
template <typename K, typename Pair, typename Hashtable>
struct map_base<K, Pair, extract1st<Pair>, false, Hashtable>
{
typedef typename Pair::second_type mapped_type;
};
template <typename K, typename Pair, typename Hashtable>
struct map_base<K, Pair, extract1st<Pair>, true, Hashtable>
{
typedef typename Pair::second_type mapped_type;
mapped_type& operator[](const K& k) {
Hashtable* h = static_cast<Hashtable*>(this);
typename Hashtable::iterator it = h->insert(std::make_pair(k, mapped_type())).first;
return it->second;
}
};
// class template rehash_base. Give hashtable the max_load_factor
// functions iff the rehash policy is prime_rehash_policy.
template <typename RehashPolicy, typename Hashtable>
struct rehash_base { };
template <typename Hashtable>
struct rehash_base<prime_rehash_policy, Hashtable>
{
float max_load_factor() const {
const Hashtable* This = static_cast<const Hashtable*>(this);
return This->rehash_policy()->max_load_factor();
}
void max_load_factor(float z) {
Hashtable* This = static_cast<Hashtable*>(this);
This->rehash_policy(prime_rehash_policy(z));
}
};
// Class template hash_code_base. Encapsulates two policy issues that
// aren't quite orthogonal.
// (1) the difference between using a ranged hash function and using
// the combination of a hash function and a range-hashing function.
// In the former case we don't have such things as hash codes, so
// we have a dummy type as placeholder.
// (2) Whether or not we cache hash codes. Caching hash codes is
// meaningless if we have a ranged hash function.
// We also put the key extraction and equality comparison function
// objects here, for convenience.
// Primary template: unused except as a hook for specializations.
template <typename Key, typename Value,
typename ExtractKey, typename Equal,
typename H1, typename H2, typename H,
bool cache_hash_code>
struct hash_code_base;
// Specialization: ranged hash function, no caching hash codes. H1
// and H2 are provided but ignored. We define a dummy hash code type.
template <typename Key, typename Value,
typename ExtractKey, typename Equal,
typename H1, typename H2, typename H>
struct hash_code_base <Key, Value, ExtractKey, Equal, H1, H2, H, false>
{
protected:
hash_code_base (const ExtractKey& ex, const Equal& eq,
const H1&, const H2&, const H& h)
: m_extract(ex), m_eq(eq), m_ranged_hash(h) { }
typedef void* hash_code_t;
hash_code_t m_hash_code (const Key& k) const { return 0; }
std::size_t bucket_index (const Key& k, hash_code_t, std::size_t N) const
{ return m_ranged_hash (k, N); }
std::size_t bucket_index (const hash_node<Value, false>* p, std::size_t N) const {
return m_ranged_hash (m_extract (p->m_v), N);
}
bool compare (const Key& k, hash_code_t, hash_node<Value, false>* n) const
{ return m_eq (k, m_extract(n->m_v)); }
void copy_code (hash_node<Value, false>*, const hash_node<Value, false>*) const { }
void m_swap(hash_code_base& x) {
m_extract.m_swap(x);
m_eq.m_swap(x);
m_ranged_hash.m_swap(x);
}
protected:
ExtractKey m_extract;
Equal m_eq;
H m_ranged_hash;
};
// No specialization for ranged hash function while caching hash codes.
// That combination is meaningless, and trying to do it is an error.
// Specialization: ranged hash function, cache hash codes. This
// combination is meaningless, so we provide only a declaration
// and no definition.
template <typename Key, typename Value,
typename ExtractKey, typename Equal,
typename H1, typename H2, typename H>
struct hash_code_base <Key, Value, ExtractKey, Equal, H1, H2, H, true>;
// Specialization: hash function and range-hashing function, no
// caching of hash codes. H is provided but ignored. Provides
// typedef and accessor required by TR1.
template <typename Key, typename Value,
typename ExtractKey, typename Equal,
typename H1, typename H2>
struct hash_code_base <Key, Value, ExtractKey, Equal, H1, H2, default_ranged_hash, false>
{
typedef H1 hasher;
hasher hash_function() const { return m_h1; }
protected:
hash_code_base (const ExtractKey& ex, const Equal& eq,
const H1& h1, const H2& h2, const default_ranged_hash&)
: m_extract(ex), m_eq(eq), m_h1(h1), m_h2(h2) { }
typedef std::size_t hash_code_t;
hash_code_t m_hash_code (const Key& k) const { return m_h1(k); }
std::size_t bucket_index (const Key&, hash_code_t c, std::size_t N) const
{ return m_h2 (c, N); }
std::size_t bucket_index (const hash_node<Value, false>* p, std::size_t N) const {
return m_h2 (m_h1 (m_extract (p->m_v)), N);
}
bool compare (const Key& k, hash_code_t, hash_node<Value, false>* n) const
{ return m_eq (k, m_extract(n->m_v)); }
void copy_code (hash_node<Value, false>*, const hash_node<Value, false>*) const { }
void m_swap(hash_code_base& x) {
m_extract.m_swap(x);
m_eq.m_swap(x);
m_h1.m_swap(x);
m_h2.m_swap(x);
}
protected:
ExtractKey m_extract;
Equal m_eq;
H1 m_h1;
H2 m_h2;
};
// Specialization: hash function and range-hashing function,
// caching hash codes. H is provided but ignored. Provides
// typedef and accessor required by TR1.
template <typename Key, typename Value,
typename ExtractKey, typename Equal,
typename H1, typename H2>
struct hash_code_base <Key, Value, ExtractKey, Equal, H1, H2, default_ranged_hash, true>
{
typedef H1 hasher;
hasher hash_function() const { return m_h1; }
protected:
hash_code_base (const ExtractKey& ex, const Equal& eq,
const H1& h1, const H2& h2, const default_ranged_hash&)
: m_extract(ex), m_eq(eq), m_h1(h1), m_h2(h2) { }
typedef std::size_t hash_code_t;
hash_code_t m_hash_code (const Key& k) const { return m_h1(k); }
std::size_t bucket_index (const Key&, hash_code_t c, std::size_t N) const
{ return m_h2 (c, N); }
std::size_t bucket_index (const hash_node<Value, true>* p, std::size_t N) const {
return m_h2 (p->hash_code, N);
}
bool compare (const Key& k, hash_code_t c, hash_node<Value, true>* n) const
{ return c == n->hash_code && m_eq (k, m_extract(n->m_v)); }
void copy_code (hash_node<Value, true>* to, const hash_node<Value, true>* from) const
{ to->hash_code = from->hash_code; }
void m_swap(hash_code_base& x) {
m_extract.m_swap(x);
m_eq.m_swap(x);
m_h1.m_swap(x);
m_h2.m_swap(x);
}
protected:
ExtractKey m_extract;
Equal m_eq;
H1 m_h1;
H2 m_h2;
};
} // namespace internal
namespace std { namespace tr1 {
//----------------------------------------------------------------------
// Class template hashtable, class definition.
// Meaning of class template hashtable's template parameters
// Key and Value: arbitrary CopyConstructible types.
// Allocator: an allocator type ([lib.allocator.requirements]) whose
// value type is Value.
// ExtractKey: function object that takes a object of type Value
// and returns a value of type Key.
// Equal: function object that takes two objects of type k and returns
// a bool-like value that is true if the two objects are considered equal.
// H1: the hash function. A unary function object with argument type
// Key and result type size_t. Return values should be distributed
// over the entire range [0, numeric_limits<size_t>:::max()].
// H2: the range-hashing function (in the terminology of Tavori and
// Dreizin). A binary function object whose argument types and result
// type are all size_t. Given arguments r and N, the return value is
// in the range [0, N).
// H: the ranged hash function (Tavori and Dreizin). A binary function
// whose argument types are Key and size_t and whose result type is
// size_t. Given arguments k and N, the return value is in the range
// [0, N). Default: h(k, N) = h2(h1(k), N). If H is anything other
// than the default, H1 and H2 are ignored.
// RehashPolicy: Policy class with three members, all of which govern
// the bucket count. n_bkt(n) returns a bucket count no smaller
// than n. bkt_for_elements(n) returns a bucket count appropriate
// for an element count of n. need_rehash(n_bkt, n_elt, n_ins)
// determines whether, if the current bucket count is n_bkt and the
// current element count is n_elt, we need to increase the bucket
// count. If so, returns make_pair(true, n), where n is the new
// bucket count. If not, returns make_pair(false, <anything>).
// ??? Right now it is hard-wired that the number of buckets never
// shrinks. Should we allow RehashPolicy to change that?
// cache_hash_code: bool. true if we store the value of the hash
// function along with the value. This is a time-space tradeoff.
// Storing it may improve lookup speed by reducing the number of times
// we need to call the Equal function.
// mutable_iterators: bool. true if hashtable::iterator is a mutable
// iterator, false if iterator and const_iterator are both const
// iterators. This is true for unordered_map and unordered_multimap,
// false for unordered_set and unordered_multiset.
// unique_keys: bool. true if the return value of hashtable::count(k)
// is always at most one, false if it may be an arbitrary number. This
// true for unordered_set and unordered_map, false for unordered_multiset
// and unordered_multimap.
template <typename Key, typename Value,
typename Allocator,
typename ExtractKey, typename Equal,
typename H1, typename H2,
typename H, typename RehashPolicy,
bool cache_hash_code,
bool mutable_iterators,
bool unique_keys>
class hashtable
: public Internal::rehash_base<RehashPolicy, hashtable<Key, Value, Allocator, ExtractKey, Equal, H1, H2, H, RehashPolicy, cache_hash_code, mutable_iterators, unique_keys> >,
public Internal::hash_code_base<Key, Value, ExtractKey, Equal, H1, H2, H, cache_hash_code>,
public Internal::map_base<Key, Value, ExtractKey, unique_keys, hashtable<Key, Value, Allocator, ExtractKey, Equal, H1, H2, H, RehashPolicy, cache_hash_code, mutable_iterators, unique_keys> >
{
public:
typedef Allocator allocator_type;
typedef Value value_type;
typedef Key key_type;
typedef Equal key_equal;
// mapped_type, if present, comes from map_base.
// hasher, if present, comes from hash_code_base.
typedef typename Allocator::difference_type difference_type;
typedef typename Allocator::size_type size_type;
typedef typename Allocator::reference reference;
typedef typename Allocator::const_reference const_reference;
typedef Internal::node_iterator<value_type, !mutable_iterators, cache_hash_code>
local_iterator;
typedef Internal::node_iterator<value_type, false, cache_hash_code>
const_local_iterator;
typedef Internal::hashtable_iterator<value_type, !mutable_iterators, cache_hash_code>
iterator;
typedef Internal::hashtable_iterator<value_type, false, cache_hash_code>
const_iterator;
private:
typedef Internal::hash_node<Value, cache_hash_code> node;
typedef typename Allocator::template rebind<node>::other node_allocator_t;
typedef typename Allocator::template rebind<node*>::other bucket_allocator_t;
private:
node_allocator_t m_node_allocator;
node** m_buckets;
size_type m_bucket_count;
size_type m_element_count;
RehashPolicy m_rehash_policy;
node* m_allocate_node (const value_type& v);
void m_deallocate_node (node* n);
void m_deallocate_nodes (node**, size_type);
node** m_allocate_buckets (size_type n);
void m_deallocate_buckets (node**, size_type n);
public: // Constructor, destructor, assignment, swap
hashtable(size_type bucket_hint,
const H1&, const H2&, const H&,
const Equal&, const ExtractKey&,
const allocator_type&);
template <typename InIter>
hashtable(InIter first, InIter last,
size_type bucket_hint,
const H1&, const H2&, const H&,
const Equal&, const ExtractKey&,
const allocator_type&);
hashtable(const hashtable&);
hashtable& operator=(const hashtable&);
~hashtable();
void swap(hashtable&);
public: // Basic container operations
iterator begin() {
iterator i(m_buckets);
if (!i.m_cur_node)
i.m_incr_bucket();
return i;
}
const_iterator begin() const {
const_iterator i(m_buckets);
if (!i.m_cur_node)
i.m_incr_bucket();
return i;
}
iterator end()
{ return iterator(m_buckets + m_bucket_count); }
const_iterator end() const
{ return const_iterator(m_buckets + m_bucket_count); }
size_type size() const { return m_element_count; }
bool empty() const { return size() == 0; }
allocator_type get_allocator() const { return m_node_allocator; }
size_type max_size() const { return m_node_allocator.max_size(); }
public: // Bucket operations
size_type bucket_count() const
{ return m_bucket_count; }
size_type max_bucket_count() const
{ return max_size(); }
size_type bucket_size (size_type n) const
{ return std::distance(begin(n), end(n)); }
size_type bucket (const key_type& k) const
{ return this->bucket_index (k, this->m_hash_code, this->m_bucket_count); }
local_iterator begin(size_type n)
{ return local_iterator(m_buckets[n]); }
local_iterator end(size_type n)
{ return local_iterator(0); }
const_local_iterator begin(size_type n) const
{ return const_local_iterator(m_buckets[n]); }
const_local_iterator end(size_type n) const
{ return const_local_iterator(0); }
float load_factor() const
{ return static_cast<float>(size()) / static_cast<float>(bucket_count()); }
// max_load_factor, if present, comes from rehash_base.
// Generalization of max_load_factor. Extension, not found in TR1. Only
// useful if RehashPolicy is something other than the default.
const RehashPolicy& rehash_policy() const { return m_rehash_policy; }
void rehash_policy (const RehashPolicy&);
public: // lookup
iterator find(const key_type&);
const_iterator find(const key_type& k) const;
size_type count(const key_type& k) const;
std::pair<iterator, iterator> equal_range(const key_type& k);
std::pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
private: // Insert and erase helper functions
// ??? This dispatching is a workaround for the fact that we don't
// have partial specialization of member templates; it would be
// better to just specialize insert on unique_keys. There may be a
// cleaner workaround.
typedef typename Internal::IF<unique_keys, std::pair<iterator, bool>, iterator>::type
Insert_Return_Type;
node* find_node (node* p, const key_type& k, typename hashtable::hash_code_t c);
std::pair<iterator, bool> insert (const value_type&, std::tr1::true_type);
iterator insert (const value_type&, std::tr1::false_type);
public: // Insert and erase
Insert_Return_Type insert (const value_type& v)
{ return this->insert (v, std::tr1::integral_constant<bool, unique_keys>()); }
Insert_Return_Type insert (const_iterator, const value_type& v)
{ return this->insert(v); }
template <typename InIter> void insert(InIter first, InIter last);
void erase(const_iterator);
size_type erase(const key_type&);
void erase(const_iterator, const_iterator);
void clear();
public:
// Set number of buckets to be apropriate for container of n element.
void rehash (size_type n);
private:
// Unconditionally change size of bucket array to n.
void m_rehash (size_type n);
};
//----------------------------------------------------------------------
// Definitions of class template hashtable's out-of-line member functions.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::node*
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::m_allocate_node (const value_type& v)
{
node* n = m_node_allocator.allocate(1);
try {
get_allocator().construct(&n->m_v, v);
n->m_next = 0;
return n;
}
catch(...) {
m_node_allocator.deallocate(n, 1);
throw;
}
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::m_deallocate_node (node* n)
{
get_allocator().destroy(&n->m_v);
m_node_allocator.deallocate(n, 1);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::m_deallocate_nodes (node** array, size_type n)
{
for (size_type i = 0; i < n; ++i) {
node* p = array[i];
while (p) {
node* tmp = p;
p = p->m_next;
m_deallocate_node (tmp);
}
array[i] = 0;
}
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::node**
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::m_allocate_buckets (size_type n)
{
bucket_allocator_t alloc(m_node_allocator);
// We allocate one extra bucket to hold a sentinel, an arbitrary
// non-null pointer. Iterator increment relies on this.
node** p = alloc.allocate(n+1);
std::fill(p, p+n, (node*) 0);
p[n] = reinterpret_cast<node*>(0x1000);
return p;
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::m_deallocate_buckets (node** p, size_type n)
{
bucket_allocator_t alloc(m_node_allocator);
alloc.deallocate(p, n+1);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::hashtable(size_type bucket_hint,
const H1& h1, const H2& h2, const H& h,
const Eq& eq, const Ex& exk,
const allocator_type& a)
: Internal::rehash_base<RP,hashtable> (),
Internal::hash_code_base<K,V,Ex,Eq,H1,H2,H,c> (exk, eq, h1, h2, h),
Internal::map_base<K,V,Ex,u,hashtable> (),
m_node_allocator(a),
m_bucket_count (0),
m_element_count (0),
m_rehash_policy ()
{
m_bucket_count = m_rehash_policy.next_bkt(bucket_hint);
m_buckets = m_allocate_buckets (m_bucket_count);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
template <typename InIter>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::hashtable(InIter f, InIter l,
size_type bucket_hint,
const H1& h1, const H2& h2, const H& h,
const Eq& eq, const Ex& exk,
const allocator_type& a)
: Internal::rehash_base<RP,hashtable> (),
Internal::hash_code_base<K,V,Ex,Eq,H1,H2,H,c> (exk, eq, h1, h2, h),
Internal::map_base<K,V,Ex,u,hashtable> (),
m_node_allocator(a),
m_bucket_count (0),
m_element_count (0),
m_rehash_policy ()
{
m_bucket_count = std::max(m_rehash_policy.next_bkt(bucket_hint),
m_rehash_policy.bkt_for_elements(Internal::distance_fw(f, l)));
m_buckets = m_allocate_buckets (m_bucket_count);
try {
for (; f != l; ++f)
this->insert (*f);
}
catch(...) {
clear();
m_deallocate_buckets (m_buckets, m_bucket_count);
throw;
}
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::hashtable(const hashtable& ht)
: Internal::rehash_base<RP,hashtable> (ht),
Internal::hash_code_base<K,V,Ex,Eq,H1,H2,H,c> (ht),
Internal::map_base<K,V,Ex,u,hashtable> (ht),
m_node_allocator(ht.get_allocator()),
m_bucket_count (ht.m_bucket_count),
m_element_count (ht.m_element_count),
m_rehash_policy (ht.m_rehash_policy)
{
m_buckets = m_allocate_buckets (m_bucket_count);
try {
for (size_t i = 0; i < ht.m_bucket_count; ++i) {
node* n = ht.m_buckets[i];
node** tail = m_buckets + i;
while (n) {
*tail = m_allocate_node (n);
(*tail).copy_code_from (n);
tail = &((*tail)->m_next);
n = n->m_next;
}
}
}
catch (...) {
clear();
m_deallocate_buckets (m_buckets, m_bucket_count);
throw;
}
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>&
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::operator= (const hashtable& ht)
{
hashtable tmp(ht);
this->swap(tmp);
return *this;
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::~hashtable()
{
clear();
m_deallocate_buckets(m_buckets, m_bucket_count);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::swap (hashtable& x)
{
// The only base class with member variables is hash_code_base. We
// define hash_code_base::m_swap because different specializations
// have different members.
Internal::hash_code_base<K, V, Ex, Eq, H1, H2, H, c>::m_swap(x);
// open LWG issue 431
// std::swap(m_node_allocator, x.m_node_allocator);
std::swap (m_rehash_policy, x.m_rehash_policy);
std::swap (m_buckets, x.m_buckets);
std::swap (m_bucket_count, x.m_bucket_count);
std::swap (m_element_count, x.m_element_count);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::rehash_policy (const RP& pol)
{
m_rehash_policy = pol;
size_type n_bkt = pol.bkt_for_elements(m_element_count);
if (n_bkt > m_bucket_count)
m_rehash (n_bkt);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::iterator
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::find (const key_type& k)
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
std::size_t n = this->bucket_index (k, code, this->bucket_count());
node* p = find_node (m_buckets[n], k, code);
return p ? iterator(p, m_buckets + n) : this->end();
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::const_iterator
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::find (const key_type& k) const
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
std::size_t n = this->bucket_index (k, code, this->bucket_count());
node* p = find_node (m_buckets[n], k, code);
return p ? const_iterator(p, m_buckets + n) : this->end();
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::size_type
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::count (const key_type& k) const
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
std::size_t n = this->bucket_index (k, code, this->bucket_count());
size_t result = 0;
for (node* p = m_buckets[n]; p ; p = p->m_next)
if (this->compare (k, code, p))
++result;
return result;
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
std::pair<typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::iterator,
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::iterator>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::equal_range (const key_type& k)
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
std::size_t n = this->bucket_index (k, code, this->bucket_count());
node** head = m_buckets + n;
node* p = find_node (*head, k, code);
if (p) {
node* p1 = p->m_next;
for (; p1 ; p1 = p1->m_next)
if (!this->compare (k, code, p1))
break;
iterator first(p, head);
iterator last(p1, head);
if (!p1)
last.m_incr_bucket();
return std::make_pair(first, last);
}
else
return std::make_pair (this->end(), this->end());
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
std::pair<typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::const_iterator,
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::const_iterator>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::equal_range (const key_type& k) const
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
std::size_t n = this->bucket_index (k, code, this->bucket_count());
node** head = m_buckets + n;
node* p = find_node (*head, k, code);
if (p) {
node* p1 = p->m_next;
for (; p1 ; p1 = p1->m_next)
if (!this->compare (k, code, p1))
break;
const_iterator first(p, head);
const_iterator last(p1, head);
if (!p1)
last.m_incr_bucket();
return std::make_pair(first, last);
}
else
return std::make_pair (this->end(), this->end());
}
// Find the node whose key compares equal to k, beginning the search
// at p (usually the head of a bucket). Return nil if no node is found.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::node*
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::find_node (node* p, const key_type& k, typename hashtable::hash_code_t code)
{
for ( ; p ; p = p->m_next)
if (this->compare (k, code, p))
return p;
return false;
}
// Insert v if no element with its key is already present.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
std::pair<typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::iterator, bool>
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::insert (const value_type& v, std::tr1::true_type)
{
const key_type& k = this->m_extract(v);
typename hashtable::hash_code_t code = this->m_hash_code (k);
size_type n = this->bucket_index (k, code, m_bucket_count);
if (node* p = find_node (m_buckets[n], k, code))
return std::make_pair(iterator(p, m_buckets + n), false);
std::pair<bool, size_t> do_rehash
= m_rehash_policy.need_rehash(m_bucket_count, m_element_count, 1);
// Allocate the new node before doing the rehash so that we don't
// do a rehash if the allocation throws.
node* new_node = m_allocate_node (v);
try {
if (do_rehash.first) {
n = this->bucket_index (k, code, do_rehash.second);
m_rehash(do_rehash.second);
}
new_node->m_next = m_buckets[n];
m_buckets[n] = new_node;
++m_element_count;
return std::make_pair(iterator (new_node, m_buckets + n), true);
}
catch (...) {
m_deallocate_node (new_node);
throw;
}
}
// Insert v unconditionally.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::iterator
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::insert (const value_type& v, std::tr1::false_type)
{
std::pair<bool, std::size_t> do_rehash
= m_rehash_policy.need_rehash(m_bucket_count, m_element_count, 1);
if (do_rehash.first)
m_rehash(do_rehash.second);
const key_type& k = this->m_extract(v);
typename hashtable::hash_code_t code = this->m_hash_code (k);
size_type n = this->bucket_index (k, code, m_bucket_count);
node* new_node = m_allocate_node (v);
node* prev = find_node (m_buckets[n], k, code);
if (prev) {
new_node->m_next = prev->m_next;
prev->m_next = new_node;
}
else {
new_node->m_next = m_buckets[n];
m_buckets[n] = new_node;
}
++m_element_count;
return iterator (new_node, m_buckets + n);
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
template <typename InIter>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::insert(InIter first, InIter last)
{
size_type n_elt = Internal::distance_fw (first, last);
std::pair<bool, std::size_t> do_rehash
= m_rehash_policy.need_rehash(m_bucket_count, m_element_count, n_elt);
if (do_rehash.first)
m_rehash(do_rehash.second);
for (; first != last; ++first)
this->insert (*first);
}
// XXX We're following the TR in giving this a return type of void,
// but that ought to change. The return type should be const_iterator,
// and it should return the iterator following the one we've erased.
// That would simplify range erase.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::erase (const_iterator i)
{
node* p = i.m_cur_node;
node* cur = *i.m_cur_bucket;
if (cur == p)
*i.m_cur_bucket = cur->m_next;
else {
node* next = cur->m_next;
while (next != p) {
cur = next;
next = cur->m_next;
}
cur->m_next = next->m_next;
}
m_deallocate_node (p);
--m_element_count;
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
typename hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::size_type
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::erase(const key_type& k)
{
typename hashtable::hash_code_t code = this->m_hash_code (k);
size_type n = this->bucket_index (k, code, m_bucket_count);
node** slot = m_buckets + n;
while (*slot && ! this->compare (k, code, *slot))
slot = &((*slot)->m_next);
while (*slot && this->compare (k, code, *slot)) {
node* n = *slot;
*slot = n->m_next;
m_deallocate_node (n);
--m_element_count;
}
}
// ??? This could be optimized by taking advantage of the bucket
// structure, but it's not clear that it's worth doing. It probably
// wouldn't even be an optimization unless the load factor is large.
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>
::erase(const_iterator first, const_iterator last)
{
while (first != last) {
const_iterator next = first;
++next;
this->erase(first);
first = next;
}
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::clear()
{
m_deallocate_nodes (m_buckets, m_bucket_count);
m_element_count = 0;
}
template <typename K, typename V,
typename A, typename Ex, typename Eq,
typename H1, typename H2, typename H, typename RP,
bool c, bool m, bool u>
void
hashtable<K,V,A,Ex,Eq,H1,H2,H,RP,c,m,u>::m_rehash (size_type N)
{
node** new_array = m_allocate_buckets (N);
try {
for (size_type i = 0; i < m_bucket_count; ++i)
while (node* p = m_buckets[i]) {
size_type new_index = this->bucket_index (p, N);
m_buckets[i] = p->m_next;
p->m_next = new_array[new_index];
new_array[new_index] = p;
}
m_deallocate_buckets (m_buckets, m_bucket_count);
m_bucket_count = N;
m_buckets = new_array;
}
catch (...) {
// A failure here means that a hash function threw an exception.
// We can't restore the previous state without calling the hash
// function again, so the only sensible recovery is to delete
// everything.
m_deallocate_nodes (new_array, N);
m_deallocate_buckets (new_array, N);
m_deallocate_nodes (m_buckets, m_bucket_count);
m_element_count = 0;
throw;
}
}
} } // Namespace std::tr1
#endif /* GNU_LIBSTDCXX_TR1_HASHTABLE_ */
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