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tdemultimedia/juk/stringhash.h

313 lines
6.7 KiB

/***************************************************************************
begin : Sun Feb 2 2003
copyright : (C) 2003 - 2004 by Scott Wheeler
email : wheeler@kde.org
***************************************************************************/
/***************************************************************************
* *
* This program 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 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef STRINGHASH_H
#define STRINGHASH_H
#include <tqptrvector.h>
#include "filehandle.h"
/**
* A simple hash representing an (un-mapped) set of data.
*/
template <class T> class Hash
{
friend class Iterator;
public:
Hash() : m_table(m_tableSize) {}
~Hash();
/**
* To combine two operations into one (that takes the same amount as each
* independantly) this inserts an item and returns true if the item was
* already in the set or false if it did not.
*/
bool insert(T value);
/**
* Returns true if the set contains the item \a value.
*/
bool contains(T value) const;
/**
* Removes an item. Returns true if the item was present and false if not.
*/
bool remove(T value);
TQValueList<T> values() const;
int hash(T key) const;
static inline int tableSize() { return m_tableSize; }
protected:
struct Node
{
Node(T value) : key(value), next(0) {}
T key;
Node *next;
};
public:
class Iterator
{
friend class Hash<T>;
public:
Iterator(const Hash<T> &hash) : m_hash(hash), m_index(0), m_node(hash.m_table[0]) {}
const T &operator*() const { return m_node->key; }
T &operator*() { return m_node->key; }
bool operator==(const Iterator &it) const { return m_index == it.m_index && m_node == it.m_node; }
bool operator!=(const Iterator &it) const { return !(it == *this); }
T &operator++();
private:
const Hash<T> &m_hash;
int m_index;
Node *m_node;
};
Iterator begin() const
{
Iterator it(*this);
while(!it.m_node && it.m_index < m_tableSize - 1) {
it.m_index++;
it.m_node = m_table[it.m_index];
}
return it;
}
Iterator end() const
{
Iterator it(*this);
it.m_node = 0;
it.m_index = m_tableSize - 1;
return it;
}
protected:
void deleteNode(Node *n);
TQPtrVector<Node> m_table;
static const int m_tableSize = 5003;
};
////////////////////////////////////////////////////////////////////////////////
// helper functions
////////////////////////////////////////////////////////////////////////////////
inline char hashStringAccess(const TQString &in, int index)
{
return in.tqunicode()[index].cell();
}
inline char hashStringAccess(const TQCString &in, int index)
{
return in[index];
}
// Based on TQGDict's hash functions, Copyright (C) 1992-2000 Trolltech AS
template <typename StringType>
inline int hashString(const StringType &s)
{
uint h = 0;
uint g;
for(uint i = 0; i < s.length(); i++)
{
h = (h << 4) + hashStringAccess(s, i);
if((g = h & 0xf0000000))
h ^= g >> 24;
h &= ~g;
}
int index = h;
if(index < 0)
index = -index;
return index;
}
////////////////////////////////////////////////////////////////////////////////
// specializations
////////////////////////////////////////////////////////////////////////////////
// StringHash
template<> inline int Hash<TQString>::hash(TQString key) const
{
return hashString(key) % tableSize();
}
typedef Hash<TQString> StringHash;
// PtrHash
template<> inline int Hash<void *>::hash(void *key) const
{
return long(key) % tableSize();
}
typedef Hash<void *> PtrHash;
// FileHandleHash
template<> inline int Hash<FileHandle>::hash(FileHandle key) const
{
return hashString(key.absFilePath()) % tableSize();
}
class FileHandleHash : public Hash<FileHandle>
{
public:
FileHandleHash() : Hash<FileHandle>() {}
FileHandle value(const TQString &key) const
{
int h = hashString(key) % tableSize();
Node *i = m_table[h];
while(i && i->key.absFilePath() != key)
i = i->next;
return i ? i->key : FileHandle::null();
}
};
////////////////////////////////////////////////////////////////////////////////
// template method implementations
////////////////////////////////////////////////////////////////////////////////
template <class T>
Hash<T>::~Hash()
{
for(int i = 0; i < m_tableSize; i++)
deleteNode(m_table[i]);
}
template <class T>
bool Hash<T>::insert(T value)
{
int h = hash(value);
Node *i = m_table[h];
Node *j = 0;
while(i) {
if(i->key == value)
return true;
else {
j = i;
i = i->next;
}
}
if(j)
j->next = new Node(value);
else
m_table.insert(h, new Node(value));
return false;
}
template <class T>
bool Hash<T>::contains(T value) const
{
int h = hash(value);
Node *i = m_table[h];
while(i && i->key != value)
i = i->next;
return bool(i);
}
template <class T>
bool Hash<T>::remove(T value)
{
int h = hash(value);
Node *previous = 0;
Node *i = m_table[h];
while(i && i->key != value) {
previous = i;
i = i->next;
}
if(!i)
return false;
if(previous)
previous->next = i->next;
else {
if(i->next)
m_table.insert(h, i->next);
else
m_table.remove(h);
}
delete i;
return true;
}
template <class T>
TQValueList<T> Hash<T>::values() const
{
TQValueList<T> l;
Node *n;
for(int i = 0; i < tableSize(); i++) {
n = m_table[i];
while(n) {
l.append(n->key);
n = n->next;
}
}
return l;
}
template <class T>
void Hash<T>::deleteNode(Node *n)
{
if(n) {
deleteNode(n->next);
delete n;
}
}
template <class T>
T &Hash<T>::Iterator::operator++()
{
if(m_node)
m_node = m_node->next;
while(!m_node && m_index < m_tableSize - 1) {
m_index++;
m_node = m_hash.m_table[m_index];
}
return m_node->key;
}
#endif