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/* multiply 8-bit fixpoint (0..1) so that 0*0==0 and 255*255==255 */
static inline unsigned char fz_mul255(unsigned char a, unsigned char b)
{
return ((a + 1) * b) >> 8;
}
/* floor / ceil towards/from +/- inf */
static inline float fz_floor(float x)
{
if (x > 0)
return floor(x);
return ceil(x);
}
static inline float fz_ceil(float x)
{
if (x > 0)
return ceil(x);
return floor(x);
}
/* divide and floor towards -inf */
static inline int fz_idiv(int a, int b)
{
return a < 0 ? (a - b + 1) / b : a / b;
}
/* from python */
static inline void fz_idivmod(int x, int y, int *d, int *m)
{
int xdivy = x / y;
int xmody = x - xdivy * y;
/* If the signs of x and y differ, and the remainder is non-0,
* C89 doesn't define whether xdivy is now the floor or the
* ceiling of the infinitely precise quotient. We want the floor,
* and we have it iff the remainder's sign matches y's.
*/
if (xmody && ((y ^ xmody) < 0)) {
xmody += y;
xdivy --;
}
*d = xdivy;
*m = xmody;
}
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