bitmap.h

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#ifndef __LINUX_BITMAP_H
#define __LINUX_BITMAP_H

#ifndef __ASSEMBLY__

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

/*
 * bitmaps provide bit arrays that consume one or more unsigned
 * longs.  The bitmap interface and available operations are listed
 * here, in bitmap.h
 *
 * Function implementations generic to all architectures are in
 * lib/bitmap.c.  Functions implementations that are architecture
 * specific are in various include/asm-<arch>/bitops.h headers
 * and other arch/<arch> specific files.
 *
 * See lib/bitmap.c for more details.
 */

/*
 * The available bitmap operations and their rough meaning in the
 * case that the bitmap is a single unsigned long are thus:
 *
 * Note that nbits should be always a compile time evaluable constant.
 * Otherwise many inlines will generate horrible code.
 *
 * bitmap_zero(dst, nbits)          *dst = 0UL
 * bitmap_fill(dst, nbits)          *dst = ~0UL
 * bitmap_copy(dst, src, nbits)         *dst = *src
 * bitmap_and(dst, src1, src2, nbits)       *dst = *src1 & *src2
 * bitmap_or(dst, src1, src2, nbits)        *dst = *src1 | *src2
 * bitmap_xor(dst, src1, src2, nbits)       *dst = *src1 ^ *src2
 * bitmap_andnot(dst, src1, src2, nbits)    *dst = *src1 & ~(*src2)
 * bitmap_complement(dst, src, nbits)       *dst = ~(*src)
 * bitmap_equal(src1, src2, nbits)      Are *src1 and *src2 equal?
 * bitmap_intersects(src1, src2, nbits)     Do *src1 and *src2 overlap?
 * bitmap_subset(src1, src2, nbits)     Is *src1 a subset of *src2?
 * bitmap_empty(src, nbits)         Are all bits zero in *src?
 * bitmap_full(src, nbits)          Are all bits set in *src?
 * bitmap_weight(src, nbits)            Hamming Weight: number set bits
 * bitmap_set(dst, pos, nbits)          Set specified bit area
 * bitmap_clear(dst, pos, nbits)        Clear specified bit area
 * bitmap_find_next_zero_area(buf, len, pos, n, mask)   Find bit free area
 * bitmap_shift_right(dst, src, n, nbits)   *dst = *src >> n
 * bitmap_shift_left(dst, src, n, nbits)    *dst = *src << n
 * bitmap_remap(dst, src, old, new, nbits)  *dst = map(old, new)(src)
 * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
 * bitmap_onto(dst, orig, relmap, nbits)    *dst = orig relative to relmap
 * bitmap_fold(dst, orig, sz, nbits)        dst bits = orig bits mod sz
 * bitmap_scnprintf(buf, len, src, nbits)   Print bitmap src to buf
 * bitmap_parse(buf, buflen, dst, nbits)    Parse bitmap dst from kernel buf
 * bitmap_parse_user(ubuf, ulen, dst, nbits)    Parse bitmap dst from user buf
 * bitmap_scnlistprintf(buf, len, src, nbits)   Print bitmap src as list to buf
 * bitmap_parselist(buf, dst, nbits)        Parse bitmap dst from kernel buf
 * bitmap_parselist_user(buf, dst, nbits)   Parse bitmap dst from user buf
 * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
 * bitmap_release_region(bitmap, pos, order)    Free specified bit region
 * bitmap_allocate_region(bitmap, pos, order)   Allocate specified bit region
 */

/*
 * Also the following operations in asm/bitops.h apply to bitmaps.
 *
 * set_bit(bit, addr)           *addr |= bit
 * clear_bit(bit, addr)         *addr &= ~bit
 * change_bit(bit, addr)        *addr ^= bit
 * test_bit(bit, addr)          Is bit set in *addr?
 * test_and_set_bit(bit, addr)      Set bit and return old value
 * test_and_clear_bit(bit, addr)    Clear bit and return old value
 * test_and_change_bit(bit, addr)   Change bit and return old value
 * find_first_zero_bit(addr, nbits) Position first zero bit in *addr
 * find_first_bit(addr, nbits)      Position first set bit in *addr
 * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
 * find_next_bit(addr, nbits, bit)  Position next set bit in *addr >= bit
 */

/*
 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
 * to declare an array named 'name' of just enough unsigned longs to
 * contain all bit positions from 0 to 'bits' - 1.
 */

/*
 * lib/bitmap.c provides these functions:
 */

extern int __bitmap_empty(const unsigned long *bitmap, int bits);
extern int __bitmap_full(const unsigned long *bitmap, int bits);
extern int __bitmap_equal(const unsigned long *bitmap1,
                    const unsigned long *bitmap2, int bits);
extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
            int bits);
extern void __bitmap_shift_right(unsigned long *dst,
                        const unsigned long *src, int shift, int bits);
extern void __bitmap_shift_left(unsigned long *dst,
                        const unsigned long *src, int shift, int bits);
extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern int __bitmap_intersects(const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern int __bitmap_subset(const unsigned long *bitmap1,
            const unsigned long *bitmap2, int bits);
extern int __bitmap_weight(const unsigned long *bitmap, int bits);

extern void bitmap_set(unsigned long *map, int i, int len);
extern void bitmap_clear(unsigned long *map, int start, int nr);
extern unsigned long bitmap_find_next_zero_area(unsigned long *map,
                     unsigned long size,
                     unsigned long start,
                     unsigned int nr,
                     unsigned long align_mask);

extern int bitmap_scnprintf(char *buf, unsigned int len,
            const unsigned long *src, int nbits);
extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
            unsigned long *dst, int nbits);
extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
            unsigned long *dst, int nbits);
extern int bitmap_scnlistprintf(char *buf, unsigned int len,
            const unsigned long *src, int nbits);
extern int bitmap_parselist(const char *buf, unsigned long *maskp,
            int nmaskbits);
extern int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
            unsigned long *dst, int nbits);
extern void bitmap_remap(unsigned long *dst, const unsigned long *src,
        const unsigned long *old, const unsigned long *new, int bits);
extern int bitmap_bitremap(int oldbit,
        const unsigned long *old, const unsigned long *new, int bits);
extern void bitmap_onto(unsigned long *dst, const unsigned long *orig,
        const unsigned long *relmap, int bits);
extern void bitmap_fold(unsigned long *dst, const unsigned long *orig,
        int sz, int bits);
extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
extern void bitmap_copy_le(void *dst, const unsigned long *src, int nbits);
extern int bitmap_ord_to_pos(const unsigned long *bitmap, int n, int bits);

#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
#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 void bitmap_fill(unsigned long *dst, int nbits)
{
    size_t nlongs = BITS_TO_LONGS(nbits);
    if (!small_const_nbits(nbits)) {
        int len = (nlongs - 1) * sizeof(unsigned long);
        memset(dst, 0xff,  len);
    }
    dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
}

static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
            int nbits)
{
    if (small_const_nbits(nbits))
        *dst = *src;
    else {
        int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
        memcpy(dst, src, len);
    }
}

static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        return (*dst = *src1 & *src2) != 0;
    return __bitmap_and(dst, src1, src2, 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);
}

static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        *dst = *src1 ^ *src2;
    else
        __bitmap_xor(dst, src1, src2, nbits);
}

static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        return (*dst = *src1 & ~(*src2)) != 0;
    return __bitmap_andnot(dst, src1, src2, nbits);
}

static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
            int nbits)
{
    if (small_const_nbits(nbits))
        *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
    else
        __bitmap_complement(dst, src, nbits);
}

static inline int bitmap_equal(const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
    else
        return __bitmap_equal(src1, src2, nbits);
}

static inline int bitmap_intersects(const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
    else
        return __bitmap_intersects(src1, src2, nbits);
}

static inline int bitmap_subset(const unsigned long *src1,
            const unsigned long *src2, int nbits)
{
    if (small_const_nbits(nbits))
        return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
    else
        return __bitmap_subset(src1, src2, nbits);
}

static inline int bitmap_empty(const unsigned long *src, int nbits)
{
    if (small_const_nbits(nbits))
        return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
    else
        return __bitmap_empty(src, nbits);
}

static inline int bitmap_full(const unsigned long *src, int nbits)
{
    if (small_const_nbits(nbits))
        return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
    else
        return __bitmap_full(src, nbits);
}

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_shift_right(unsigned long *dst,
            const unsigned long *src, int n, int nbits)
{
    if (small_const_nbits(nbits))
        *dst = *src >> n;
    else
        __bitmap_shift_right(dst, src, n, nbits);
}

static inline void bitmap_shift_left(unsigned long *dst,
            const unsigned long *src, int n, int nbits)
{
    if (small_const_nbits(nbits))
        *dst = (*src << n) & BITMAP_LAST_WORD_MASK(nbits);
    else
        __bitmap_shift_left(dst, src, n, nbits);
}

static inline int bitmap_parse(const char *buf, unsigned int buflen,
            unsigned long *maskp, int nmaskbits)
{
    return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
}

#endif /* __ASSEMBLY__ */

#endif /* __LINUX_BITMAP_H */