/* 
 * Copyright 2005-2007 Gerald Schmidt.
 * 
 * This file is part of Xml Copy Editor.
 * 
 * Xml Copy Editor 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; version 2 of the License.
 * 
 * Xml Copy Editor 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 Xml Copy Editor; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef STRINGSET_H
#define STRINGSET_H

#include <string>
#include <stdexcept>
#include <cmath>
#include <climits>
#ifdef __WXMSW__
#include <mem.h>
#endif

template<class T>
class StringSetNode
{
public:
    StringSetNode ( T *keyParameter, size_t lenParameter )
    {
        next = NULL;
        len = lenParameter;
        key = new T[len];
        memcpy ( key, keyParameter, len * sizeof ( T ) );
    }
    ~StringSetNode()
    {
        delete[] key;
    }
    StringSetNode<T> *next;
    T *key;
    size_t len;
};

template<class T>
class StringSet
{
public:
    StringSet (
        int hashSizePower = 19
    );
    ~StringSet();
    StringSet ( const StringSet<T>& );
    StringSet& operator= ( const StringSet<T>& );
    inline bool empty();
    inline int count();
    StringSetNode<T> *insert ( std::basic_string<T> &s );
    StringSetNode<T> *insert ( T *s, size_t len, uint32_t hash = UINT_MAX );
    StringSetNode<T> *find ( std::basic_string<T> &s );
    StringSetNode<T> *find ( T *s, size_t len, uint32_t hash = UINT_MAX );
    void clear();
private:
    bool emptyFlag;
    uint32_t hashSize, hashMask, nodeCount;
    StringSetNode<T> **table;
    uint32_t hash ( const char *s, size_t len );
    void allocateHashTable ( uint32_t hashSize );
};

template<class T>
StringSet<T>::StringSet ( int hashSizePower )
{
    if ( hashSizePower < 1 )
        throw std::runtime_error ( "StringSet: invalid parameter" );
    hashSize = ( int ) pow ( ( double ) 2, ( double ) hashSizePower );
    hashMask = hashSize - 1;
    nodeCount = 0;
    allocateHashTable ( hashSize );
}

template<class T>
StringSet<T>::~StringSet()
{
    if ( !empty() )
        clear();
    delete[] table;
}

template<class T>
StringSet<T>::StringSet ( const StringSet<T>& d )
{
    hashSize = d.hashSize;
    hashMask = hashSize - 1;
    nodeCount = 0;
    allocateHashTable ( hashSize );
    StringSetNode<T> *np;
    for ( uint32_t i = 0; i < d.hashSize; ++i )
        for ( np = d.table[i]; np != NULL; np = np->next )
            insert ( np->key, np->len, i );
}

template<class T>
StringSet<T>& StringSet<T>::operator= ( const StringSet<T>& d )
{
    if ( this != &d )
    {
        clear();
        StringSetNode<T> *np;
        for ( uint32_t i = 0; i < d.hashSize; ++i )
            for ( np = d.table[i]; np != NULL; np = np->next )
                insert ( np->key, np->len, i );
    }
    return *this;
}

// see 'one-at-a-time hash' (http://burtleburtle.net/bob/hash/doobs.html)
template<class T>
uint32_t StringSet<T>::hash ( const char *key, size_t len )
{
    uint32_t hash;
    for ( hash = 0; len--; ++key )
    {
        hash += *key;
        hash += ( hash << 10 );
        hash ^= ( hash >> 6 );
    }
    hash += ( hash << 3 );
    hash ^= ( hash >> 11 );
    hash += ( hash << 15 );
    return ( hash & hashMask );
}

template<class T>
StringSetNode<T> *StringSet<T>::find ( std::basic_string<T> &s )
{
    return find ( ( T * ) s.data(), s.size() );
}

template<class T>
StringSetNode<T> *StringSet<T>::find ( T *s, size_t len, uint32_t hashValue )
{
    if ( hashValue == UINT_MAX )
        hashValue = hash ( ( const char* ) s, len * sizeof ( T ) );
    StringSetNode<T> *np;
    for ( np = table[hashValue]; np != NULL; np = np->next )
        if ( len == np->len && ( memcmp ( s, np->key, len ) == 0 ) )
            return np;
    return NULL;
}

template<class T>
StringSetNode<T> *StringSet<T>::insert ( std::basic_string<T> &s )
{
    return insert ( ( T * ) s.data(), s.size() );
}

template<class T>
StringSetNode<T> *StringSet<T>::insert ( T *s, size_t len, uint32_t hashValue )
{
    if ( hashValue == UINT_MAX )
        hashValue = hash ( ( const char* ) s, len * sizeof ( T ) );
    StringSetNode<T> *np;
    if ( ( np = find ( s, len, hashValue ) ) == NULL )
    {
        np = new StringSetNode<T> ( s, len );
        np->next = table[hashValue];
        table[hashValue] = np;
        ++nodeCount;
    }
    return np;
}

template<class T>
void StringSet<T>::clear()
{
    if ( !nodeCount )
        return;
    StringSetNode<T> *np, *memory;
    for ( uint32_t i = 0; i < hashSize; ++i )
    {
        for ( np = table[i]; np != NULL; np = memory )
        {
            memory = np->next;
            delete np;
        }
        table[i] = NULL;
    }
    nodeCount = 0;
}

template<class T>
int StringSet<T>::count()
{
    return nodeCount;
}

template<class T>
bool StringSet<T>::empty()
{
    return ( nodeCount ) ? false : true;
}

template<class T>
void StringSet<T>::allocateHashTable ( uint32_t hashSize )
{
    table = new StringSetNode<T> *[hashSize];
    memset ( table, 0, sizeof ( StringSetNode<T> * ) * hashSize );
}

#endif