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/*
* DDS GIMP plugin
*
* Copyright (C) 2004-2012 Shawn Kirst <skirst@gmail.com>,
* with parts (C) 2003 Arne Reuter <homepage@arnereuter.de> where specified.
*
* This program 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.
*
* This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef __IMATH_H__
#define __IMATH_H__
#ifndef MIN
# ifdef __GNUC__
# define MIN(a, b) ({typeof(a) _a=(a); typeof(b) _b=(b); _a < _b ? _a : _b;})
# else
# define MIN(a, b) ((a) < (b) ? (a) : (b))
# endif
#endif
#ifndef MAX
# ifdef __GNUC__
# define MAX(a, b) ({typeof(a) _a=(a); typeof(b) _b=(b); _a > _b ? _a : _b;})
# else
# define MAX(a, b) ((a) > (b) ? (a) : (b))
# endif
#endif
#define IS_POW2(x) (!((x) & ((x) - 1)))
#define IS_MUL4(x) (((x) & 3) == 0)
/* round integer x up to next multiple of 4 */
#define RND_MUL4(x) ((x) + (4 - ((x) & 3)))
static inline int
mul8bit (int a,
int b)
{
int t = a * b + 128;
return (t + (t >> 8)) >> 8;
}
static inline int
blerp (int a,
int b,
int x)
{
return a + mul8bit(b - a, x);
}
static inline int
icerp (int a,
int b,
int c,
int d,
int x)
{
int p = (d - c) - (a - b);
int q = (a - b) - p;
int r = c - a;
return (x * (x * (x * p + (q << 7)) + (r << 14)) + (b << 21)) >> 21;
}
#endif /* __IMATH_H__ */
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