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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef RUNTIME_VM_HASH_MAP_H_
#define RUNTIME_VM_HASH_MAP_H_
#include "vm/growable_array.h" // For Malloc, EmptyBase
#include "vm/zone.h"
namespace dart {
template <typename KeyValueTrait, typename B, typename Allocator = Zone>
class BaseDirectChainedHashMap : public B {
public:
explicit BaseDirectChainedHashMap(Allocator* allocator)
: array_size_(0),
lists_size_(0),
count_(0),
array_(NULL),
lists_(NULL),
free_list_head_(kNil),
allocator_(allocator) {
ResizeLists(kInitialSize);
Resize(kInitialSize);
}
BaseDirectChainedHashMap(const BaseDirectChainedHashMap& other);
virtual ~BaseDirectChainedHashMap() {
allocator_->template Free<HashMapListElement>(array_, array_size_);
allocator_->template Free<HashMapListElement>(lists_, lists_size_);
}
void Insert(typename KeyValueTrait::Pair kv);
bool Remove(typename KeyValueTrait::Key key);
typename KeyValueTrait::Value LookupValue(
typename KeyValueTrait::Key key) const;
typename KeyValueTrait::Pair* Lookup(typename KeyValueTrait::Key key) const;
bool HasKey(typename KeyValueTrait::Key key) const {
return Lookup(key) != NULL;
}
intptr_t Size() const { return count_; }
bool IsEmpty() const { return count_ == 0; }
virtual void Clear() {
if (!IsEmpty()) {
count_ = 0;
InitArray(array_, array_size_);
InitArray(lists_, lists_size_);
lists_[0].next = kNil;
for (intptr_t i = 1; i < lists_size_; ++i) {
lists_[i].next = i - 1;
}
free_list_head_ = lists_size_ - 1;
}
}
class Iterator {
public:
typename KeyValueTrait::Pair* Next();
void Reset() {
array_index_ = 0;
list_index_ = kNil;
}
private:
explicit Iterator(const BaseDirectChainedHashMap& map)
: map_(map), array_index_(0), list_index_(kNil) {}
const BaseDirectChainedHashMap& map_;
intptr_t array_index_;
intptr_t list_index_;
template <typename T, typename Bs, typename A>
friend class BaseDirectChainedHashMap;
};
Iterator GetIterator() const { return Iterator(*this); }
protected:
// A linked list of T values. Stored in arrays.
struct HashMapListElement {
HashMapListElement() : kv(), next(kNil) {}
typename KeyValueTrait::Pair kv;
intptr_t next; // Index in the array of the next list element.
};
static const intptr_t kNil = -1; // The end of a linked list
static void InitArray(HashMapListElement* array, intptr_t size) {
for (intptr_t i = 0; i < size; ++i) {
array[i] = HashMapListElement();
}
}
// Must be a power of 2.
static const intptr_t kInitialSize = 16;
void Resize(intptr_t new_size);
void ResizeLists(intptr_t new_size);
uword Bound(uword value) const { return value & (array_size_ - 1); }
intptr_t array_size_;
intptr_t lists_size_;
intptr_t count_; // The number of values stored in the HashMap.
HashMapListElement* array_; // Primary store - contains the first value
// with a given hash. Colliding elements are stored in linked lists.
HashMapListElement* lists_; // The linked lists containing hash collisions.
intptr_t free_list_head_; // Unused elements in lists_ are on the free list.
Allocator* allocator_;
};
template <typename KeyValueTrait, typename B, typename Allocator>
BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::BaseDirectChainedHashMap(
const BaseDirectChainedHashMap& other)
: B(),
array_size_(other.array_size_),
lists_size_(other.lists_size_),
count_(other.count_),
array_(other.allocator_->template Alloc<HashMapListElement>(
other.array_size_)),
lists_(other.allocator_->template Alloc<HashMapListElement>(
other.lists_size_)),
free_list_head_(other.free_list_head_),
allocator_(other.allocator_) {
memmove(array_, other.array_, array_size_ * sizeof(HashMapListElement));
memmove(lists_, other.lists_, lists_size_ * sizeof(HashMapListElement));
}
template <typename KeyValueTrait, typename B, typename Allocator>
typename KeyValueTrait::Pair*
BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::Lookup(
typename KeyValueTrait::Key key) const {
const typename KeyValueTrait::Value kNoValue =
KeyValueTrait::ValueOf(typename KeyValueTrait::Pair());
uword hash = static_cast<uword>(KeyValueTrait::Hashcode(key));
uword pos = Bound(hash);
if (KeyValueTrait::ValueOf(array_[pos].kv) != kNoValue) {
if (KeyValueTrait::IsKeyEqual(array_[pos].kv, key)) {
return &array_[pos].kv;
}
intptr_t next = array_[pos].next;
while (next != kNil) {
if (KeyValueTrait::IsKeyEqual(lists_[next].kv, key)) {
return &lists_[next].kv;
}
next = lists_[next].next;
}
}
return NULL;
}
template <typename KeyValueTrait, typename B, typename Allocator>
typename KeyValueTrait::Value
BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::LookupValue(
typename KeyValueTrait::Key key) const {
const typename KeyValueTrait::Value kNoValue =
KeyValueTrait::ValueOf(typename KeyValueTrait::Pair());
typename KeyValueTrait::Pair* pair = Lookup(key);
return (pair == NULL) ? kNoValue : KeyValueTrait::ValueOf(*pair);
}
template <typename KeyValueTrait, typename B, typename Allocator>
typename KeyValueTrait::Pair*
BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::Iterator::Next() {
const typename KeyValueTrait::Value kNoValue =
KeyValueTrait::ValueOf(typename KeyValueTrait::Pair());
if (array_index_ < map_.array_size_) {
// If we're not in the middle of a list, find the next array slot.
if (list_index_ == kNil) {
while ((array_index_ < map_.array_size_) &&
KeyValueTrait::ValueOf(map_.array_[array_index_].kv) == kNoValue) {
array_index_++;
}
if (array_index_ < map_.array_size_) {
// When we're done with the list, we'll continue with the next array
// slot.
const intptr_t old_array_index = array_index_;
array_index_++;
list_index_ = map_.array_[old_array_index].next;
return &map_.array_[old_array_index].kv;
} else {
return NULL;
}
}
// Otherwise, return the current lists_ entry, advancing list_index_.
intptr_t current = list_index_;
list_index_ = map_.lists_[current].next;
return &map_.lists_[current].kv;
}
return NULL;
}
template <typename KeyValueTrait, typename B, typename Allocator>
void BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::Resize(
intptr_t new_size) {
const typename KeyValueTrait::Value kNoValue =
KeyValueTrait::ValueOf(typename KeyValueTrait::Pair());
ASSERT(new_size > count_);
// Hashing the values into the new array has no more collisions than in the
// old hash map, so we can use the existing lists_ array, if we are careful.
// Make sure we have at least one free element.
if (free_list_head_ == kNil) {
ResizeLists(lists_size_ << 1);
}
HashMapListElement* new_array =
allocator_->template Alloc<HashMapListElement>(new_size);
InitArray(new_array, new_size);
HashMapListElement* old_array = array_;
intptr_t old_size = array_size_;
intptr_t old_count = count_;
count_ = 0;
array_size_ = new_size;
array_ = new_array;
if (old_array != NULL) {
// Iterate over all the elements in lists, rehashing them.
for (intptr_t i = 0; i < old_size; ++i) {
if (KeyValueTrait::ValueOf(old_array[i].kv) != kNoValue) {
intptr_t current = old_array[i].next;
while (current != kNil) {
Insert(lists_[current].kv);
intptr_t next = lists_[current].next;
lists_[current].next = free_list_head_;
free_list_head_ = current;
current = next;
}
// Rehash the directly stored value.
Insert(old_array[i].kv);
}
}
}
USE(old_count);
ASSERT(count_ == old_count);
allocator_->template Free<HashMapListElement>(old_array, old_size);
}
template <typename KeyValueTrait, typename B, typename Allocator>
void BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::ResizeLists(
intptr_t new_size) {
ASSERT(new_size > lists_size_);
HashMapListElement* new_lists =
allocator_->template Alloc<HashMapListElement>(new_size);
InitArray(new_lists, new_size);
HashMapListElement* old_lists = lists_;
intptr_t old_size = lists_size_;
lists_size_ = new_size;
lists_ = new_lists;
if (old_lists != NULL) {
memmove(lists_, old_lists, old_size * sizeof(HashMapListElement));
}
for (intptr_t i = old_size; i < lists_size_; ++i) {
lists_[i].next = free_list_head_;
free_list_head_ = i;
}
allocator_->template Free<HashMapListElement>(old_lists, old_size);
}
template <typename KeyValueTrait, typename B, typename Allocator>
void BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::Insert(
typename KeyValueTrait::Pair kv) {
const typename KeyValueTrait::Value kNoValue =
KeyValueTrait::ValueOf(typename KeyValueTrait::Pair());
ASSERT(KeyValueTrait::ValueOf(kv) != kNoValue);
// Resizing when half of the hashtable is filled up.
if (count_ >= array_size_ >> 1) Resize(array_size_ << 1);
ASSERT(count_ < array_size_);
count_++;
uword pos = Bound(
static_cast<uword>(KeyValueTrait::Hashcode(KeyValueTrait::KeyOf(kv))));
if (KeyValueTrait::ValueOf(array_[pos].kv) == kNoValue) {
array_[pos].kv = kv;
array_[pos].next = kNil;
} else {
if (free_list_head_ == kNil) {
ResizeLists(lists_size_ << 1);
}
intptr_t new_element_pos = free_list_head_;
ASSERT(new_element_pos != kNil);
free_list_head_ = lists_[free_list_head_].next;
lists_[new_element_pos].kv = kv;
lists_[new_element_pos].next = array_[pos].next;
ASSERT(array_[pos].next == kNil ||
KeyValueTrait::ValueOf(lists_[array_[pos].next].kv) != kNoValue);
array_[pos].next = new_element_pos;
}
}
template <typename KeyValueTrait, typename B, typename Allocator>
bool BaseDirectChainedHashMap<KeyValueTrait, B, Allocator>::Remove(
typename KeyValueTrait::Key key) {
uword pos = Bound(static_cast<uword>(KeyValueTrait::Hashcode(key)));
// Check to see if the first element in the bucket is the one we want to
// remove.
if (KeyValueTrait::KeyOf(array_[pos].kv) == key) {
if (array_[pos].next == kNil) {
array_[pos] = HashMapListElement();
} else {
intptr_t next = array_[pos].next;
array_[pos] = lists_[next];
lists_[next] = HashMapListElement();
lists_[next].next = free_list_head_;
free_list_head_ = next;
}
count_--;
return true;
}
intptr_t current = array_[pos].next;
// If there's only the single element in the bucket and it does not match the
// key to be removed, just return.
if (current == kNil) {
return false;
}
// Check the case where the second element in the bucket is the one to be
// removed.
if (KeyValueTrait::KeyOf(lists_[current].kv) == key) {
array_[pos].next = lists_[current].next;
lists_[current] = HashMapListElement();
lists_[current].next = free_list_head_;
free_list_head_ = current;
count_--;
return true;
}
// Finally, iterate through the rest of the bucket to see if we can find the
// entry that matches our key.
intptr_t previous;
while (KeyValueTrait::KeyOf(lists_[current].kv) != key) {
previous = current;
current = lists_[current].next;
if (current == kNil) {
// Could not find entry with provided key to remove.
return false;
}
}
lists_[previous].next = lists_[current].next;
lists_[current] = HashMapListElement();
lists_[current].next = free_list_head_;
free_list_head_ = current;
count_--;
return true;
}
template <typename KeyValueTrait>
class DirectChainedHashMap
: public BaseDirectChainedHashMap<KeyValueTrait, ValueObject> {
public:
DirectChainedHashMap()
: BaseDirectChainedHashMap<KeyValueTrait, ValueObject>(
ASSERT_NOTNULL(Thread::Current()->zone())) {}
explicit DirectChainedHashMap(Zone* zone)
: BaseDirectChainedHashMap<KeyValueTrait, ValueObject>(
ASSERT_NOTNULL(zone)) {}
};
template <typename KeyValueTrait>
class MallocDirectChainedHashMap
: public BaseDirectChainedHashMap<KeyValueTrait, EmptyBase, Malloc> {
public:
MallocDirectChainedHashMap()
: BaseDirectChainedHashMap<KeyValueTrait, EmptyBase, Malloc>(NULL) {}
};
template <typename T>
class PointerKeyValueTrait {
public:
typedef T* Value;
typedef T* Key;
typedef T* Pair;
static Key KeyOf(Pair kv) { return kv; }
static Value ValueOf(Pair kv) { return kv; }
static inline intptr_t Hashcode(Key key) { return key->Hashcode(); }
static inline bool IsKeyEqual(Pair kv, Key key) { return kv->Equals(key); }
};
template <typename T>
class NumbersKeyValueTrait {
public:
typedef T Value;
typedef intptr_t Key;
typedef T Pair;
static intptr_t KeyOf(Pair kv) { return kv.first(); }
static T ValueOf(Pair kv) { return kv; }
static inline intptr_t Hashcode(Key key) { return key; }
static inline bool IsKeyEqual(Pair kv, Key key) { return kv.first() == key; }
};
template <typename K, typename V>
class RawPointerKeyValueTrait {
public:
typedef K* Key;
typedef V Value;
struct Pair {
Key key;
Value value;
Pair() : key(NULL), value() {}
Pair(const Key key, const Value& value) : key(key), value(value) {}
Pair(const Pair& other) : key(other.key), value(other.value) {}
};
static Key KeyOf(Pair kv) { return kv.key; }
static Value ValueOf(Pair kv) { return kv.value; }
static intptr_t Hashcode(Key key) { return reinterpret_cast<intptr_t>(key); }
static bool IsKeyEqual(Pair kv, Key key) { return kv.key == key; }
};
template <typename V>
class IntKeyRawPointerValueTrait {
public:
typedef intptr_t Key;
typedef V Value;
struct Pair {
Key key;
Value value;
Pair() : key(NULL), value() {}
Pair(const Key key, const Value& value) : key(key), value(value) {}
Pair(const Pair& other) : key(other.key), value(other.value) {}
};
static Key KeyOf(Pair kv) { return kv.key; }
static Value ValueOf(Pair kv) { return kv.value; }
static intptr_t Hashcode(Key key) { return key; }
static bool IsKeyEqual(Pair kv, Key key) { return kv.key == key; }
};
template <typename V>
class IntMap : public DirectChainedHashMap<IntKeyRawPointerValueTrait<V> > {
public:
typedef typename IntKeyRawPointerValueTrait<V>::Key Key;
typedef typename IntKeyRawPointerValueTrait<V>::Value Value;
typedef typename IntKeyRawPointerValueTrait<V>::Pair Pair;
inline void Insert(const Key& key, const Value& value) {
Pair pair(key, value);
DirectChainedHashMap<IntKeyRawPointerValueTrait<V> >::Insert(pair);
}
inline V Lookup(const Key& key) {
Pair* pair =
DirectChainedHashMap<IntKeyRawPointerValueTrait<V> >::Lookup(key);
if (pair == NULL) {
return V();
} else {
return pair->value;
}
}
inline Pair* LookupPair(const Key& key) {
return DirectChainedHashMap<IntKeyRawPointerValueTrait<V> >::Lookup(key);
}
};
} // namespace dart
#endif // RUNTIME_VM_HASH_MAP_H_