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tdelibs/khtml/misc/multimap.h

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/*
* This file is part of the DOM implementation for KDE.
*
* Copyright (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef _MultiMap_h_
#define _MultiMap_h_
#include <qptrdict.h>
#include <qptrlist.h>
#include <assert.h>
#include <stdlib.h>
template<class T> class MultiMapPtrList;
// KMultiMap is an implementaition of a Map with multiple entries per key.
// It is originally designed to work like a shell for QPtrDict<QPtrList>, but
// QPtrList have been replaced with a much faster hash set.
template<class T>
class KMultiMap {
public:
KMultiMap() : dict(257) { dict.setAutoDelete(true); }
~KMultiMap() {};
typedef MultiMapPtrList<T> List;
void append(void* key, T* element) {
List *list = dict.find(key);
if (!list){
list = new List(8);
dict.insert(key, list);
}
list->append(element);
}
void remove(void* key, T* element) {
List *list = dict.find(key);
if (list) {
list->remove(element);
if (list->isEmpty()) dict.remove(key);
}
}
void remove(void* key) {
dict.remove(key);
}
List* find(void* key) {
return dict.find(key);
}
private:
QPtrDict<List> dict;
};
static inline unsigned int stupidHash(void* ptr)
{
unsigned long val = (unsigned long)ptr;
// remove alignment and multiply by a prime unlikely to be a factor of size
val = (val >> 4) * 1237;
return val;
}
#define START_PTRLIST_SIZE 4
#define MAX_PTRLIST_SIZE 27
class PtrListEntry {
public:
PtrListEntry(unsigned int log_size) : count(0), log_size(log_size), search(log_size), next(0) {
// entry = new T* [size];
assert(log_size < MAX_PTRLIST_SIZE);
entry = (void**)calloc ((1<<log_size), sizeof(void*));
}
~PtrListEntry() {
// delete[] entry;
free(entry);
}
bool insert(void* e) {
unsigned int t_size = size();
if (count == t_size) return false;
unsigned int hash = stupidHash(e);
void** firstFree = 0;
// Only let elements be placed 'search' spots from their hash
for(unsigned int j=0; j<search; j++) {
unsigned int i = (hash + j) & (t_size-1); // modulo size
// We need check to all hashes in 'search' to garuantee uniqueness
if (entry[i] == 0) {
if (!firstFree)
firstFree = entry + i;
} else
if (entry[i] == e)
return true;
}
if (firstFree) {
*firstFree = e;
count++;
return true;
}
// We had more than 'search' collisions
if (count < (t_size/3)*2) {
// only 2/3 full => increase search
unsigned int s = search *2;
if (s >= t_size) s = t_size;
search = s;
return insert(e);
}
return false;
}
// Insert another smaller set into this one
// Is only garuantied to succede when this PtrList is new
void insert(PtrListEntry* listEntry) {
assert(size() >= listEntry->count * 2);
unsigned int old_size = 1U << listEntry->log_size;
for(unsigned int i = 0; i < old_size; i++) {
bool s = true;
void *e = listEntry->entry[i];
if (e) s = insert(e);
assert(s);
}
}
bool remove(void* e) {
if (count == 0) return false;
unsigned int size = (1U<<log_size);
unsigned int hash = stupidHash(e);
// Elements are at most placed 'search' spots from their hash
for(unsigned int j=0; j<search; j++) {
unsigned int i = (hash + j) & (size-1); // modulo size
if (entry[i] == e) {
entry[i] = 0;
count--;
return true;
}
}
return false;
}
bool contains(void* e) {
if (count == 0) return false;
unsigned int t_size = size();
unsigned int hash = stupidHash(e);
// Elements are at most placed 'search' spots from their hash
for(unsigned int j=0; j<search; j++) {
unsigned int i = (hash + j) & (t_size-1); // modulo size
if (entry[i] == e) return true;
}
return false;
}
void* at(unsigned int i) const {
assert (i < (1U<<log_size));
return entry[i];
}
bool isEmpty() const {
return count == 0;
}
bool isFull() const {
return count == size();
}
unsigned int size() const {
return (1U << log_size);
}
unsigned int count;
const unsigned short log_size;
unsigned short search;
PtrListEntry *next;
void** entry;
};
// An unsorted and unique PtrList that is implement as a linked list of hash-sets
// Optimized for fast insert and fast lookup
template<class T>
class MultiMapPtrList {
public:
MultiMapPtrList(unsigned int init_size= 16) : m_first(0), m_current(0), m_pos(0) {
assert(init_size > 0);
unsigned int s = init_size - 1;
unsigned int log_size = 0;
while (s > 0) {
log_size++;
s = s >> 1;
}
m_first = new PtrListEntry(log_size);
}
MultiMapPtrList(const MultiMapPtrList& ptrList) : m_first(0), m_current(0), m_pos(0) {
unsigned int t_count = ptrList.count();
unsigned int log_size = 0;
while (t_count > 0) {
log_size++;
t_count = t_count >> 1;
}
// At least as large as the largest ptrListEntry in the original
if (t_count < ptrList.m_first->log_size) log_size = ptrList.m_first->log_size;
m_first = new PtrListEntry(log_size);
PtrListEntry *t_current = ptrList.m_first;
while (t_current) {
unsigned int t_size = t_current->size();
for(unsigned int i=0; i < t_size; i++) {
void* e = t_current->at(i);
if (e != 0) {
bool t = m_first->insert(e);
if (!t) {
// Make a new, but keep the size
PtrListEntry *t_new = new PtrListEntry(log_size);
t_new->insert(e);
t_new->next = m_first;
m_first = t_new;
}
}
}
t_current = t_current->next;
}
}
~MultiMapPtrList() {
PtrListEntry *t_next, *t_current = m_first;
while (t_current) {
t_next = t_current->next;
delete t_current;
t_current = t_next;
}
}
void append(T* e) {
PtrListEntry *t_last = 0, *t_current = m_first;
int count = 0;
while (t_current) {
if (t_current->insert(e)) return;
t_last = t_current;
t_current = t_current->next;
count++;
}
// Create new hash-set
unsigned int newsize = m_first->log_size+1;
if (newsize > MAX_PTRLIST_SIZE) newsize = MAX_PTRLIST_SIZE;
t_current = new PtrListEntry(newsize);
bool t = t_current->insert(e);
assert(t);
// Prepend it to the list, for insert effeciency
t_current->next = m_first;
m_first = t_current;
// ### rehash some of the smaller sets
/*
if (count > 4) {
// rehash the last in the new
t_current->insert(t_last);
}*/
}
void remove(T* e) {
PtrListEntry *t_next, *t_last = 0, *t_current = m_first;
// Remove has to check every PtrEntry.
while (t_current) {
t_next = t_current->next;
if (t_current->remove(e) && t_current->isEmpty()) {
if (t_last) {
t_last->next = t_current->next;
}
else {
assert (m_first == t_current);
m_first = t_current->next;
}
delete t_current;
} else {
t_last = t_current;
}
t_current = t_next;
}
}
bool contains(T* e) {
PtrListEntry *t_current = m_first;
while (t_current) {
if (t_current->contains(e)) return true;
t_current = t_current->next;
}
return false;
}
bool isEmpty() {
if (!m_first) return true;
PtrListEntry *t_current = m_first;
while (t_current) {
if (!t_current->isEmpty()) return false;
t_current = t_current->next;
}
return true;
}
unsigned int count() const {
unsigned int t_count = 0;
PtrListEntry *t_current = m_first;
while (t_current) {
t_count += t_current->count;
t_current = t_current->next;
}
return t_count;
}
// Iterator functions:
T* first() {
m_current = m_first;
m_pos = 0;
// skip holes
if (m_current && !m_current->at(m_pos))
return next();
else
return current();
}
T* current() {
if (!m_current)
return (T*)0;
else
return (T*)m_current->at(m_pos);
}
T* next() {
if (!m_current) return (T*)0;
m_pos++;
if (m_pos >= m_current->size()) {
m_current = m_current->next;
m_pos = 0;
}
// skip holes
if (m_current && !m_current->at(m_pos))
return next();
else
return current();
}
private:
PtrListEntry *m_first;
// iteration:
PtrListEntry *m_current;
unsigned int m_pos;
};
#undef START_PTRLIST_SIZE
#undef MAX_PTRLIST_SIZE
#endif