quadrilateralcowboy/idlib/containers/BinSearch.h
2020-06-12 14:06:25 -07:00

138 lines
3.7 KiB
C++

/*
===========================================================================
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__ */