xenia-canary/third_party/crunch/crnlib/crn_hash_map.h

877 lines
23 KiB
C++

// File: crn_hash_map.h
// See Copyright Notice and license at the end of inc/crnlib.h
//
// Notes:
// stl-like hash map/hash set, with predictable performance across platforms/compilers/C run times/etc.
// Hash function ref: http://www.brpreiss.com/books/opus4/html/page215.html
// Compared for performance against VC9's std::hash_map.
// Linear probing, auto resizes on ~50% load factor.
// Uses Knuth's multiplicative method (Fibonacci hashing).
#pragma once
#include "crn_sparse_array.h"
#include "crn_sparse_bit_array.h"
#include "crn_hash.h"
namespace crnlib
{
template <typename T>
struct hasher
{
inline size_t operator() (const T& key) const { return static_cast<size_t>(key); }
};
template <typename T>
struct bit_hasher
{
inline size_t operator() (const T& key) const { return static_cast<size_t>(fast_hash(&key, sizeof(key))); }
};
template <typename T>
struct equal_to
{
inline bool operator()(const T& a, const T& b) const { return a == b; }
};
// Important: The Hasher and Equals objects must be bitwise movable!
template<typename Key, typename Value = empty_type, typename Hasher = hasher<Key>, typename Equals = equal_to<Key> >
class hash_map
{
friend class iterator;
friend class const_iterator;
enum state
{
cStateInvalid = 0,
cStateValid = 1
};
enum
{
cMinHashSize = 4U
};
public:
typedef hash_map<Key, Value, Hasher, Equals> hash_map_type;
typedef std::pair<Key, Value> value_type;
typedef Key key_type;
typedef Value referent_type;
typedef Hasher hasher_type;
typedef Equals equals_type;
hash_map() :
m_hash_shift(32), m_num_valid(0), m_grow_threshold(0)
{
}
hash_map(const hash_map& other) :
m_values(other.m_values),
m_hash_shift(other.m_hash_shift),
m_hasher(other.m_hasher),
m_equals(other.m_equals),
m_num_valid(other.m_num_valid),
m_grow_threshold(other.m_grow_threshold)
{
}
hash_map& operator= (const hash_map& other)
{
if (this == &other)
return *this;
clear();
m_values = other.m_values;
m_hash_shift = other.m_hash_shift;
m_num_valid = other.m_num_valid;
m_grow_threshold = other.m_grow_threshold;
m_hasher = other.m_hasher;
m_equals = other.m_equals;
return *this;
}
inline ~hash_map()
{
clear();
}
const Equals& get_equals() const { return m_equals; }
Equals& get_equals() { return m_equals; }
void set_equals(const Equals& equals) { m_equals = equals; }
const Hasher& get_hasher() const { return m_hasher; }
Hasher& get_hasher() { return m_hasher; }
void set_hasher(const Hasher& hasher) { m_hasher = hasher; }
inline void clear()
{
if (!m_values.empty())
{
if (CRNLIB_HAS_DESTRUCTOR(Key) || CRNLIB_HAS_DESTRUCTOR(Value))
{
node* p = &get_node(0);
node* p_end = p + m_values.size();
uint num_remaining = m_num_valid;
while (p != p_end)
{
if (p->state)
{
destruct_value_type(p);
num_remaining--;
if (!num_remaining)
break;
}
p++;
}
}
m_values.clear_no_destruction();
m_hash_shift = 32;
m_num_valid = 0;
m_grow_threshold = 0;
}
}
inline void reset()
{
if (!m_num_valid)
return;
if (CRNLIB_HAS_DESTRUCTOR(Key) || CRNLIB_HAS_DESTRUCTOR(Value))
{
node* p = &get_node(0);
node* p_end = p + m_values.size();
uint num_remaining = m_num_valid;
while (p != p_end)
{
if (p->state)
{
destruct_value_type(p);
p->state = cStateInvalid;
num_remaining--;
if (!num_remaining)
break;
}
p++;
}
}
else if (sizeof(node) <= 32)
{
memset(&m_values[0], 0, m_values.size_in_bytes());
}
else
{
node* p = &get_node(0);
node* p_end = p + m_values.size();
uint num_remaining = m_num_valid;
while (p != p_end)
{
if (p->state)
{
p->state = cStateInvalid;
num_remaining--;
if (!num_remaining)
break;
}
p++;
}
}
m_num_valid = 0;
}
inline uint size()
{
return m_num_valid;
}
inline uint get_table_size()
{
return m_values.size();
}
inline bool empty()
{
return !m_num_valid;
}
inline void reserve(uint new_capacity)
{
uint new_hash_size = math::maximum(1U, new_capacity);
new_hash_size = new_hash_size * 2U;
if (!math::is_power_of_2(new_hash_size))
new_hash_size = math::next_pow2(new_hash_size);
new_hash_size = math::maximum<uint>(cMinHashSize, new_hash_size);
if (new_hash_size > m_values.size())
rehash(new_hash_size);
}
class const_iterator;
class iterator
{
friend class hash_map<Key, Value, Hasher, Equals>;
friend class hash_map<Key, Value, Hasher, Equals>::const_iterator;
public:
inline iterator() : m_pTable(NULL), m_index(0) { }
inline iterator(hash_map_type& table, uint index) : m_pTable(&table), m_index(index) { }
inline iterator(const iterator& other) : m_pTable(other.m_pTable), m_index(other.m_index) { }
inline iterator& operator= (const iterator& other)
{
m_pTable = other.m_pTable;
m_index = other.m_index;
return *this;
}
// post-increment
inline iterator operator++(int)
{
iterator result(*this);
++*this;
return result;
}
// pre-increment
inline iterator& operator++()
{
probe();
return *this;
}
inline value_type& operator*() const { return *get_cur(); }
inline value_type* operator->() const { return get_cur(); }
inline bool operator == (const iterator& b) const { return (m_pTable == b.m_pTable) && (m_index == b.m_index); }
inline bool operator != (const iterator& b) const { return !(*this == b); }
inline bool operator == (const const_iterator& b) const { return (m_pTable == b.m_pTable) && (m_index == b.m_index); }
inline bool operator != (const const_iterator& b) const { return !(*this == b); }
private:
hash_map_type* m_pTable;
uint m_index;
inline value_type* get_cur() const
{
CRNLIB_ASSERT(m_pTable && (m_index < m_pTable->m_values.size()));
CRNLIB_ASSERT(m_pTable->get_node_state(m_index) == cStateValid);
return &m_pTable->get_node(m_index);
}
inline void probe()
{
CRNLIB_ASSERT(m_pTable);
m_index = m_pTable->find_next(m_index);
}
};
class const_iterator
{
friend class hash_map<Key, Value, Hasher, Equals>;
friend class hash_map<Key, Value, Hasher, Equals>::iterator;
public:
inline const_iterator() : m_pTable(NULL), m_index(0) { }
inline const_iterator(const hash_map_type& table, uint index) : m_pTable(&table), m_index(index) { }
inline const_iterator(const iterator& other) : m_pTable(other.m_pTable), m_index(other.m_index) { }
inline const_iterator(const const_iterator& other) : m_pTable(other.m_pTable), m_index(other.m_index) { }
inline const_iterator& operator= (const const_iterator& other)
{
m_pTable = other.m_pTable;
m_index = other.m_index;
return *this;
}
inline const_iterator& operator= (const iterator& other)
{
m_pTable = other.m_pTable;
m_index = other.m_index;
return *this;
}
// post-increment
inline const_iterator operator++(int)
{
const_iterator result(*this);
++*this;
return result;
}
// pre-increment
inline const_iterator& operator++()
{
probe();
return *this;
}
inline const value_type& operator*() const { return *get_cur(); }
inline const value_type* operator->() const { return get_cur(); }
inline bool operator == (const const_iterator& b) const { return (m_pTable == b.m_pTable) && (m_index == b.m_index); }
inline bool operator != (const const_iterator& b) const { return !(*this == b); }
inline bool operator == (const iterator& b) const { return (m_pTable == b.m_pTable) && (m_index == b.m_index); }
inline bool operator != (const iterator& b) const { return !(*this == b); }
private:
const hash_map_type* m_pTable;
uint m_index;
inline const value_type* get_cur() const
{
CRNLIB_ASSERT(m_pTable && (m_index < m_pTable->m_values.size()));
CRNLIB_ASSERT(m_pTable->get_node_state(m_index) == cStateValid);
return &m_pTable->get_node(m_index);
}
inline void probe()
{
CRNLIB_ASSERT(m_pTable);
m_index = m_pTable->find_next(m_index);
}
};
inline const_iterator begin() const
{
if (!m_num_valid)
return end();
return const_iterator(*this, find_next(-1));
}
inline const_iterator end() const
{
return const_iterator(*this, m_values.size());
}
inline iterator begin()
{
if (!m_num_valid)
return end();
return iterator(*this, find_next(-1));
}
inline iterator end()
{
return iterator(*this, m_values.size());
}
// insert_result.first will always point to inserted key/value (or the already existing key/value).
// insert_resutt.second will be true if a new key/value was inserted, or false if the key already existed (in which case first will point to the already existing value).
typedef std::pair<iterator, bool> insert_result;
inline insert_result insert(const Key& k, const Value& v = Value())
{
insert_result result;
if (!insert_no_grow(result, k, v))
{
grow();
// This must succeed.
if (!insert_no_grow(result, k, v))
{
CRNLIB_FAIL("insert() failed");
}
}
return result;
}
inline insert_result insert(const value_type& v)
{
return insert(v.first, v.second);
}
inline const_iterator find(const Key& k) const
{
return const_iterator(*this, find_index(k));
}
inline iterator find(const Key& k)
{
return iterator(*this, find_index(k));
}
inline bool erase(const Key& k)
{
int i = find_index(k);
if (i >= static_cast<int>(m_values.size()))
return false;
node* pDst = &get_node(i);
destruct_value_type(pDst);
pDst->state = cStateInvalid;
m_num_valid--;
for ( ; ; )
{
int r, j = i;
node* pSrc = pDst;
do
{
if (!i)
{
i = m_values.size() - 1;
pSrc = &get_node(i);
}
else
{
i--;
pSrc--;
}
if (!pSrc->state)
return true;
r = hash_key(pSrc->first);
} while ((i <= r && r < j) || (r < j && j < i) || (j < i && i <= r));
move_node(pDst, pSrc);
pDst = pSrc;
}
}
inline void swap(hash_map_type& other)
{
m_values.swap(other.m_values);
utils::swap(m_hash_shift, other.m_hash_shift);
utils::swap(m_num_valid, other.m_num_valid);
utils::swap(m_grow_threshold, other.m_grow_threshold);
utils::swap(m_hasher, other.m_hasher);
utils::swap(m_equals, other.m_equals);
}
private:
struct node : public value_type
{
uint8 state;
};
static inline void construct_value_type(value_type* pDst, const Key& k, const Value& v)
{
if (CRNLIB_IS_BITWISE_COPYABLE(Key))
memcpy(&pDst->first, &k, sizeof(Key));
else
scalar_type<Key>::construct(&pDst->first, k);
if (CRNLIB_IS_BITWISE_COPYABLE(Value))
memcpy(&pDst->second, &v, sizeof(Value));
else
scalar_type<Value>::construct(&pDst->second, v);
}
static inline void construct_value_type(value_type* pDst, const value_type* pSrc)
{
if ((CRNLIB_IS_BITWISE_COPYABLE(Key)) && (CRNLIB_IS_BITWISE_COPYABLE(Value)))
{
memcpy(pDst, pSrc, sizeof(value_type));
}
else
{
if (CRNLIB_IS_BITWISE_COPYABLE(Key))
memcpy(&pDst->first, &pSrc->first, sizeof(Key));
else
scalar_type<Key>::construct(&pDst->first, pSrc->first);
if (CRNLIB_IS_BITWISE_COPYABLE(Value))
memcpy(&pDst->second, &pSrc->second, sizeof(Value));
else
scalar_type<Value>::construct(&pDst->second, pSrc->second);
}
}
static inline void destruct_value_type(value_type* p)
{
scalar_type<Key>::destruct(&p->first);
scalar_type<Value>::destruct(&p->second);
}
// Moves *pSrc to *pDst efficiently.
// pDst should NOT be constructed on entry.
static inline void move_node(node* pDst, node* pSrc)
{
CRNLIB_ASSERT(!pDst->state);
if (CRNLIB_IS_BITWISE_COPYABLE_OR_MOVABLE(Key) && CRNLIB_IS_BITWISE_COPYABLE_OR_MOVABLE(Value))
{
memcpy(pDst, pSrc, sizeof(node));
}
else
{
if (CRNLIB_IS_BITWISE_COPYABLE_OR_MOVABLE(Key))
memcpy(&pDst->first, &pSrc->first, sizeof(Key));
else
{
scalar_type<Key>::construct(&pDst->first, pSrc->first);
scalar_type<Key>::destruct(&pSrc->first);
}
if (CRNLIB_IS_BITWISE_COPYABLE_OR_MOVABLE(Value))
memcpy(&pDst->second, &pSrc->second, sizeof(Value));
else
{
scalar_type<Value>::construct(&pDst->second, pSrc->second);
scalar_type<Value>::destruct(&pSrc->second);
}
pDst->state = cStateValid;
}
pSrc->state = cStateInvalid;
}
struct raw_node
{
inline raw_node()
{
node* p = reinterpret_cast<node*>(this);
p->state = cStateInvalid;
}
inline ~raw_node()
{
node* p = reinterpret_cast<node*>(this);
if (p->state)
hash_map_type::destruct_value_type(p);
}
inline raw_node(const raw_node& other)
{
node* pDst = reinterpret_cast<node*>(this);
const node* pSrc = reinterpret_cast<const node*>(&other);
if (pSrc->state)
{
hash_map_type::construct_value_type(pDst, pSrc);
pDst->state = cStateValid;
}
else
pDst->state = cStateInvalid;
}
inline raw_node& operator= (const raw_node& rhs)
{
if (this == &rhs)
return *this;
node* pDst = reinterpret_cast<node*>(this);
const node* pSrc = reinterpret_cast<const node*>(&rhs);
if (pSrc->state)
{
if (pDst->state)
{
pDst->first = pSrc->first;
pDst->second = pSrc->second;
}
else
{
hash_map_type::construct_value_type(pDst, pSrc);
pDst->state = cStateValid;
}
}
else if (pDst->state)
{
hash_map_type::destruct_value_type(pDst);
pDst->state = cStateInvalid;
}
return *this;
}
uint8 m_bits[sizeof(node)];
};
typedef crnlib::vector<raw_node> node_vector;
node_vector m_values;
uint m_hash_shift;
Hasher m_hasher;
Equals m_equals;
uint m_num_valid;
uint m_grow_threshold;
inline int hash_key(const Key& k) const
{
CRNLIB_ASSERT((1U << (32U - m_hash_shift)) == m_values.size());
uint hash = static_cast<uint>(m_hasher(k));
// Fibonacci hashing
hash = (2654435769U * hash) >> m_hash_shift;
CRNLIB_ASSERT(hash < m_values.size());
return hash;
}
inline const node& get_node(uint index) const
{
return *reinterpret_cast<const node*>(&m_values[index]);
}
inline node& get_node(uint index)
{
return *reinterpret_cast<node*>(&m_values[index]);
}
inline state get_node_state(uint index) const
{
return static_cast<state>(get_node(index).state);
}
inline void set_node_state(uint index, bool valid)
{
get_node(index).state = valid;
}
inline void grow()
{
rehash(math::maximum<uint>(cMinHashSize, m_values.size() * 2U));
}
inline void rehash(uint new_hash_size)
{
CRNLIB_ASSERT(new_hash_size >= m_num_valid);
CRNLIB_ASSERT(math::is_power_of_2(new_hash_size));
if ((new_hash_size < m_num_valid) || (new_hash_size == m_values.size()))
return;
hash_map new_map;
new_map.m_values.resize(new_hash_size);
new_map.m_hash_shift = 32U - math::floor_log2i(new_hash_size);
CRNLIB_ASSERT(new_hash_size == (1U << (32U - new_map.m_hash_shift)));
new_map.m_grow_threshold = UINT_MAX;
node* pNode = reinterpret_cast<node*>(m_values.begin());
node* pNode_end = pNode + m_values.size();
while (pNode != pNode_end)
{
if (pNode->state)
{
new_map.move_into(pNode);
if (new_map.m_num_valid == m_num_valid)
break;
}
pNode++;
}
new_map.m_grow_threshold = (new_hash_size + 1U) >> 1U;
m_values.clear_no_destruction();
m_hash_shift = 32;
swap(new_map);
}
inline uint find_next(int index) const
{
index++;
if (index >= static_cast<int>(m_values.size()))
return index;
const node* pNode = &get_node(index);
for ( ; ; )
{
if (pNode->state)
break;
if (++index >= static_cast<int>(m_values.size()))
break;
pNode++;
}
return index;
}
inline uint find_index(const Key& k) const
{
if (m_num_valid)
{
int index = hash_key(k);
const node* pNode = &get_node(index);
if (pNode->state)
{
if (m_equals(pNode->first, k))
return index;
const int orig_index = index;
for ( ; ; )
{
if (!index)
{
index = m_values.size() - 1;
pNode = &get_node(index);
}
else
{
index--;
pNode--;
}
if (index == orig_index)
break;
if (!pNode->state)
break;
if (m_equals(pNode->first, k))
return index;
}
}
}
return m_values.size();
}
inline bool insert_no_grow(insert_result& result, const Key& k, const Value& v = Value())
{
if (!m_values.size())
return false;
int index = hash_key(k);
node* pNode = &get_node(index);
if (pNode->state)
{
if (m_equals(pNode->first, k))
{
result.first = iterator(*this, index);
result.second = false;
return true;
}
const int orig_index = index;
for ( ; ; )
{
if (!index)
{
index = m_values.size() - 1;
pNode = &get_node(index);
}
else
{
index--;
pNode--;
}
if (orig_index == index)
return false;
if (!pNode->state)
break;
if (m_equals(pNode->first, k))
{
result.first = iterator(*this, index);
result.second = false;
return true;
}
}
}
if (m_num_valid >= m_grow_threshold)
return false;
construct_value_type(pNode, k, v);
pNode->state = cStateValid;
m_num_valid++;
CRNLIB_ASSERT(m_num_valid <= m_values.size());
result.first = iterator(*this, index);
result.second = true;
return true;
}
inline void move_into(node* pNode)
{
int index = hash_key(pNode->first);
node* pDst_node = &get_node(index);
if (pDst_node->state)
{
const int orig_index = index;
for ( ; ; )
{
if (!index)
{
index = m_values.size() - 1;
pDst_node = &get_node(index);
}
else
{
index--;
pDst_node--;
}
if (index == orig_index)
{
CRNLIB_ASSERT(false);
return;
}
if (!pDst_node->state)
break;
}
}
move_node(pDst_node, pNode);
m_num_valid++;
}
};
template<typename Key, typename Value, typename Hasher, typename Equals>
struct bitwise_movable< hash_map<Key, Value, Hasher, Equals> > { enum { cFlag = true }; };
template<typename Key, typename Value, typename Hasher, typename Equals>
inline void swap(hash_map<Key, Value, Hasher, Equals>& a, hash_map<Key, Value, Hasher, Equals>& b)
{
a.swap(b);
}
extern void hash_map_test();
} // namespace crnlib