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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2017-2020 Intel Corporation. All rights reserved.
// Copyright (C) 2009 Akinobu Mita. All rights reserved.
/* originally copied from the Linux kernel bitmap implementation */
#include <stdlib.h>
#include <util/size.h>
#include <util/util.h>
#include <util/bitmap.h>
#include <ccan/endian/endian.h>
#include <ccan/minmax/minmax.h>
#include <ccan/short_types/short_types.h>
unsigned long *bitmap_alloc(unsigned long nbits)
{
return calloc(BITS_TO_LONGS(nbits), sizeof(unsigned long));
}
void bitmap_set(unsigned long *map, unsigned int start, int len)
{
unsigned long *p = map + BIT_WORD(start);
const unsigned int size = start + len;
int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
while (len - bits_to_set >= 0) {
*p |= mask_to_set;
len -= bits_to_set;
bits_to_set = BITS_PER_LONG;
mask_to_set = ~0UL;
p++;
}
if (len) {
mask_to_set &= BITMAP_LAST_WORD_MASK(size);
*p |= mask_to_set;
}
}
void bitmap_clear(unsigned long *map, unsigned int start, int len)
{
unsigned long *p = map + BIT_WORD(start);
const unsigned int size = start + len;
int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
while (len - bits_to_clear >= 0) {
*p &= ~mask_to_clear;
len -= bits_to_clear;
bits_to_clear = BITS_PER_LONG;
mask_to_clear = ~0UL;
p++;
}
if (len) {
mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
*p &= ~mask_to_clear;
}
}
/**
* test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*/
int test_bit(unsigned int nr, const volatile unsigned long *addr)
{
return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}
/*
* This is a common helper function for find_next_bit and
* find_next_zero_bit. The difference is the "invert" argument, which
* is XORed with each fetched word before searching it for one bits.
*/
static unsigned long _find_next_bit(const unsigned long *addr,
unsigned long nbits, unsigned long start, unsigned long invert)
{
unsigned long tmp;
if (!nbits || start >= nbits)
return nbits;
tmp = addr[start / BITS_PER_LONG] ^ invert;
/* Handle 1st word. */
tmp &= BITMAP_FIRST_WORD_MASK(start);
start = round_down(start, BITS_PER_LONG);
while (!tmp) {
start += BITS_PER_LONG;
if (start >= nbits)
return nbits;
tmp = addr[start / BITS_PER_LONG] ^ invert;
}
return min(start + __builtin_ffsl(tmp), nbits);
}
/*
* Find the next set bit in a memory region.
*/
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
return _find_next_bit(addr, size, offset, 0UL);
}
unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
return _find_next_bit(addr, size, offset, ~0UL);
}
int bitmap_full(const unsigned long *src, unsigned int nbits)
{
if (small_const_nbits(nbits))
return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
return find_next_zero_bit(src, nbits, 0UL) == nbits;
}
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