bitmap.h

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#ifndef _PERF_BITOPS_H
#define _PERF_BITOPS_H

#include <string.h>
#include <linux/bitops.h>

int __bitmap_weight(const unsigned long *bitmap, int bits);
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
         const unsigned long *bitmap2, int bits);

#define BITMAP_LAST_WORD_MASK(nbits)                    \
(                                   \
    ((nbits) % BITS_PER_LONG) ?                 \
        (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL       \
)

#define small_const_nbits(nbits) \
    (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)

static inline void bitmap_zero(unsigned long *dst, int nbits)
{
    if (small_const_nbits(nbits))
        *dst = 0UL;
    else {
        int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
        memset(dst, 0, len);
    }
}

static inline int bitmap_weight(const unsigned long *src, int nbits)
{
    if (small_const_nbits(nbits))
        return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
    return __bitmap_weight(src, nbits);
}

static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
                 const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        *dst = *src1 | *src2;
    else
        __bitmap_or(dst, src1, src2, nbits);
}

#endif /* _PERF_BITOPS_H */