qemu-e2k/include/qemu/bitmap.h
Peter Xu d7788151a0 bitmap: provide to_le/from_le helpers
Provide helpers to convert bitmaps to little endian format. It can be
used when we want to send one bitmap via network to some other hosts.

One thing to mention is that, these helpers only solve the problem of
endianess, but it does not solve the problem of different word size on
machines (the bitmaps managing same count of bits may contains different
size when malloced). So we need to take care of the size alignment issue
on the callers for now.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2017-09-22 14:11:25 +02:00

258 lines
8.9 KiB
C

/*
* Bitmap Module
*
* Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
*
* 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/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_set_atomic(dst, pos, nbits) Set specified bit area with atomic ops
* bitmap_clear(dst, pos, nbits) Clear specified bit area
* bitmap_test_and_clear_atomic(dst, pos, nbits) Test and clear area
* bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
* bitmap_to_le(dst, src, nbits) Convert bitmap to little endian
* bitmap_from_le(dst, src, nbits) Convert bitmap from little endian
*/
/*
* 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_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
#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, long bits);
int slow_bitmap_full(const unsigned long *bitmap, long bits);
int slow_bitmap_equal(const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
long bits);
int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
int slow_bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
long slow_bitmap_count_one(const unsigned long *bitmap, long nbits);
static inline unsigned long *bitmap_try_new(long nbits)
{
long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
return g_try_malloc0(len);
}
static inline unsigned long *bitmap_new(long nbits)
{
unsigned long *ptr = bitmap_try_new(nbits);
if (ptr == NULL) {
abort();
}
return ptr;
}
static inline void bitmap_zero(unsigned long *dst, long nbits)
{
if (small_nbits(nbits)) {
*dst = 0UL;
} else {
long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
memset(dst, 0, len);
}
}
static inline void bitmap_fill(unsigned long *dst, long nbits)
{
size_t nlongs = BITS_TO_LONGS(nbits);
if (!small_nbits(nbits)) {
long 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,
long nbits)
{
if (small_nbits(nbits)) {
*dst = *src;
} else {
long 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, long 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, long 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, long 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, long 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,
long 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, long 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, long 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, long 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, long nbits)
{
if (small_nbits(nbits)) {
return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
} else {
return slow_bitmap_intersects(src1, src2, nbits);
}
}
static inline long bitmap_count_one(const unsigned long *bitmap, long nbits)
{
if (small_nbits(nbits)) {
return ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits));
} else {
return slow_bitmap_count_one(bitmap, nbits);
}
}
void bitmap_set(unsigned long *map, long i, long len);
void bitmap_set_atomic(unsigned long *map, long i, long len);
void bitmap_clear(unsigned long *map, long start, long nr);
bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr);
void bitmap_copy_and_clear_atomic(unsigned long *dst, unsigned long *src,
long nr);
unsigned long bitmap_find_next_zero_area(unsigned long *map,
unsigned long size,
unsigned long start,
unsigned long nr,
unsigned long align_mask);
static inline unsigned long *bitmap_zero_extend(unsigned long *old,
long old_nbits, long new_nbits)
{
long new_len = BITS_TO_LONGS(new_nbits) * sizeof(unsigned long);
unsigned long *new = g_realloc(old, new_len);
bitmap_clear(new, old_nbits, new_nbits - old_nbits);
return new;
}
void bitmap_to_le(unsigned long *dst, const unsigned long *src,
long nbits);
void bitmap_from_le(unsigned long *dst, const unsigned long *src,
long nbits);
#endif /* BITMAP_H */