/* Public domain. */

#ifndef _LINUX_AVERAGE_H
#define _LINUX_AVERAGE_H

#include <sys/types.h>
#include <lib/libkern/libkern.h>

#define DECLARE_EWMA(name, precision, recip)                    \
struct ewma_##name {                                            \
        u_long value;                                           \
};                                                              \
                                                                \
static inline void                                              \
ewma_##name##_init(struct ewma_##name *p)                       \
{                                                               \
        p->value = 0;                                           \
}                                                               \
                                                                \
static inline void                                              \
ewma_##name##_add(struct ewma_##name *p, u_long value)          \
{                                                               \
        u_long shift = fls(recip) - 1;                          \
                                                                \
        if (p->value == 0)                                      \
                p->value = (value << (precision));              \
        else                                                    \
                p->value = ((((p->value << shift) - p->value) + \
                    (value << (precision))) >> shift);          \
}                                                               \
                                                                \
static inline u_long                                            \
ewma_##name##_read(struct ewma_##name *p)                       \
{                                                               \
        return (p->value >> (precision));                       \
}

#endif