bitmap: add a generic bitmap and bitops library

[qemu.git] / bitmap.h

/*
 * Bitmap Module
 *
 * Copyright (C) 2010 Corentin Chary <[email protected]>
 *
 * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
 *
 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
 * See the COPYING.LIB file in the top-level directory.
 */

#ifndef BITMAP_H
#define BITMAP_H

#include "qemu-common.h"
#include "bitops.h"

/*
 * 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_empty(src, nbits)			Are all bits zero in *src?
 * bitmap_full(src, nbits)			Are all bits set in *src?
 * 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
 */

/*
 * Also the following operations 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
 */

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

#define DECLARE_BITMAP(name,bits)                  \
	unsigned long name[BITS_TO_LONGS(bits)]

#define small_nbits(nbits)                      \
	((nbits) <= BITS_PER_LONG)

int slow_bitmap_empty(const unsigned long *bitmap, int bits);
int slow_bitmap_full(const unsigned long *bitmap, int bits);
int slow_bitmap_equal(const unsigned long *bitmap1,
                   const unsigned long *bitmap2, int bits);
void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
                         int bits);
void slow_bitmap_shift_right(unsigned long *dst,
                          const unsigned long *src, int shift, int bits);
void slow_bitmap_shift_left(unsigned long *dst,
                         const unsigned long *src, int shift, int bits);
int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
                 const unsigned long *bitmap2, int bits);
void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
                 const unsigned long *bitmap2, int bits);
void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
                  const unsigned long *bitmap2, int bits);
int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
                    const unsigned long *bitmap2, int bits);
int slow_bitmap_intersects(const unsigned long *bitmap1,
			const unsigned long *bitmap2, int bits);

static inline unsigned long *bitmap_new(int nbits)
{
    int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
    return qemu_mallocz(len);
}

static inline void bitmap_zero(unsigned long *dst, int nbits)
{
    if (small_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_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_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_nbits(nbits)) {
        return (*dst = *src1 & *src2) != 0;
    }
    return slow_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_nbits(nbits)) {
        *dst = *src1 | *src2;
    } else {
        slow_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_nbits(nbits)) {
        *dst = *src1 ^ *src2;
    } else {
        slow_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_nbits(nbits)) {
        return (*dst = *src1 & ~(*src2)) != 0;
    }
    return slow_bitmap_andnot(dst, src1, src2, nbits);
}

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

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

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

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

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

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

#endif /* BITMAP_H */