BinSearch.h

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/*
===========================================================================

Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  

Doom 3 Source Code 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 3 of the License, or
(at your option) any later version.

Doom 3 Source Code 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 Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

#ifndef __BINSEARCH_H__
#define __BINSEARCH_H__

/*
===============================================================================

        Binary Search templates

        The array elements have to be ordered in increasing order.

===============================================================================
*/

/*
====================
idBinSearch_GreaterEqual

        Finds the last array element which is smaller than the given value.
====================
*/
template< class type >
ID_INLINE int idBinSearch_Less( const type *array, const int arraySize, const type &value ) {
        int len = arraySize;
        int mid = len;
        int offset = 0;
        while( mid > 0 ) {
                mid = len >> 1;
                if ( array[offset+mid] < value ) {
                        offset += mid;
                }
                len -= mid;
        }
        return offset;
}

/*
====================
idBinSearch_GreaterEqual

        Finds the last array element which is smaller than or equal to the given value.
====================
*/
template< class type >
ID_INLINE int idBinSearch_LessEqual( const type *array, const int arraySize, const type &value ) {
        int len = arraySize;
        int mid = len;
        int offset = 0;
        while( mid > 0 ) {
                mid = len >> 1;
                if ( array[offset+mid] <= value ) {
                        offset += mid;
                }
                len -= mid;
        }
        return offset;
}

/*
====================
idBinSearch_Greater

        Finds the first array element which is greater than the given value.
====================
*/
template< class type >
ID_INLINE int idBinSearch_Greater( const type *array, const int arraySize, const type &value ) {
        int len = arraySize;
        int mid = len;
        int offset = 0;
        int res = 0;
        while( mid > 0 ) {
                mid = len >> 1;
                if ( array[offset+mid] > value ) {
                        res = 0;
                } else {
                        offset += mid;
                        res = 1;
                }
                len -= mid;
        }
        return offset+res;
}

/*
====================
idBinSearch_GreaterEqual

        Finds the first array element which is greater than or equal to the given value.
====================
*/
template< class type >
ID_INLINE int idBinSearch_GreaterEqual( const type *array, const int arraySize, const type &value ) {
        int len = arraySize;
        int mid = len;
        int offset = 0;
        int res = 0;
        while( mid > 0 ) {
                mid = len >> 1;
                if ( array[offset+mid] >= value ) {
                        res = 0;
                } else {
                        offset += mid;
                        res = 1;
                }
                len -= mid;
        }
        return offset+res;
}

#endif /* !__BINSEARCH_H__ */