60 lines
2.1 KiB
C
60 lines
2.1 KiB
C
|
/**
|
||
|
|
* @file modadd.h
|
||
|
|
* @author Ambroz Bizjak <ambrop7@gmail.com>
|
||
|
|
*
|
||
|
|
* @section LICENSE
|
||
|
|
*
|
||
|
|
* Redistribution and use in source and binary forms, with or without
|
||
|
|
* modification, are permitted provided that the following conditions are met:
|
||
|
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer.
|
||
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
|
* documentation and/or other materials provided with the distribution.
|
||
|
|
* 3. Neither the name of the author nor the
|
||
|
|
* names of its contributors may be used to endorse or promote products
|
||
|
|
* derived from this software without specific prior written permission.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
|
||
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
||
|
|
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||
|
|
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
|
||
|
|
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
||
|
|
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||
|
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
||
|
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
||
|
|
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
*
|
||
|
|
* @section DESCRIPTION
|
||
|
|
*
|
||
|
|
* Modular addition macro.
|
||
|
|
*
|
||
|
|
* Calculates (x + y) mod m, assuming
|
||
|
|
* 0 <= x < m and 0 <= y < m.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef BADVPN_MISC_MODADD_H
|
||
|
|
#define BADVPN_MISC_MODADD_H
|
||
|
|
|
||
|
|
#include <misc/debug.h>
|
||
|
|
|
||
|
|
#define DECLARE_BMODADD(type, name) \
|
||
|
|
static type bmodadd_##name (type x, type y, type m) \
|
||
|
|
{ \
|
||
|
|
ASSERT(x >= 0) \
|
||
|
|
ASSERT(x < m) \
|
||
|
|
ASSERT(y >= 0) \
|
||
|
|
ASSERT(y < m) \
|
||
|
|
\
|
||
|
|
if (y >= m - x) { \
|
||
|
|
return (y - (m - x)); \
|
||
|
|
} else { \
|
||
|
|
return (x + y); \
|
||
|
|
} \
|
||
|
|
} \
|
||
|
|
|
||
|
|
DECLARE_BMODADD(int, int)
|
||
|
|
|
||
|
|
#endif
|