Sort.h

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/******************************************************************************************[Sort.h]
Copyright (c) 2003-2007, Niklas Een, Niklas Sorensson
Copyright (c) 2007-2010, Niklas Sorensson
 
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#ifndef Minisat_Sort_h
#define Minisat_Sort_h
 
#include "Vec.h"
 
//=================================================================================================
// Some sorting algorithms for vec's
 
namespace Minisat
{
    template<class T>
    struct LessThan_default
    {
        bool operator ()( T x, T y )
        {
            return x < y;
        }
    };
 
    template<class T, class LessThan>
    void selectionSort( T* array, int size, LessThan lt )
    {
        int i, j, best_i;
        T   tmp;
 
        for( i = 0; i < size - 1; i++ )
        {
            best_i = i;
            for( j = i + 1; j < size; j++ )
            {
                if( lt( array[j], array[best_i] ) )
                    best_i = j;
            }
            tmp           = array[i];
            array[i]      = array[best_i];
            array[best_i] = tmp;
        }
    }
 
    template<class T>
    static inline void selectionSort( T* array, int size )
    {
        selectionSort( array, size, LessThan_default<T>() );
    }
 
    template<class T, class LessThan>
    void sort( T* array, int size, LessThan lt )
    {
        if( size <= 15 )
            selectionSort( array, size, lt );
 
        else
        {
            T pivot = array[size / 2];
            T   tmp;
            int i = -1;
            int j = size;
 
            for( ; ; )
            {
                do
                    i++;
                while( lt( array[i], pivot ) );
                do
                    j--;
                while( lt( pivot, array[j] ) );
 
                if( i >= j )
                    break;
 
                tmp      = array[i];
                array[i] = array[j];
                array[j] = tmp;
            }
 
            sort( array, i, lt );
            sort( &array[i], size - i, lt );
        }
    }
 
    template<class T>
    static inline void sort( T* array, int size )
    {
        sort( array, size, LessThan_default<T>() );
    }
 
    //=================================================================================================
    // For 'vec's:
 
    template<class T, class LessThan>
    void sort( vec<T>& v, LessThan lt )
    {
        sort( (T*)v, v.size(), lt );
    }
 
    template<class T>
    void sort( vec<T>& v )
    {
        sort( v, LessThan_default<T>() );
    }
 
    //=================================================================================================
}
 
#endif