/*************************************************************************
 *
 * Copyright (C) 2018-2020 Ruilin Peng (Nick) <pymumu@gmail.com>.
 *
 * smartdns is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * smartdns is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#ifndef _PERF_BITOPS_H
#define _PERF_BITOPS_H

#include <string.h>
#include <stdlib.h>
#include "bitops.h"
#include "findbit.h"


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

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);
int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
		 const unsigned long *bitmap2, unsigned int bits);

#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))

#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, unsigned int nbits)
{
	unsigned int nlongs = BITS_TO_LONGS(nbits);
	if (!small_const_nbits(nbits)) {
		unsigned int len = (nlongs - 1) * sizeof(unsigned long);
		memset(dst, 0xff,  len);
	}
	dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
}

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

	return find_first_bit(src, nbits) == nbits;
}

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

	return find_first_zero_bit(src, nbits) == 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_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);
}

/**
 * test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 */
static inline int test_and_set_bit(int nr, unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
	unsigned long old;

	old = *p;
	*p = old | mask;

	return (old & mask) != 0;
}

/**
 * bitmap_alloc - Allocate bitmap
 * @nbits: Number of bits
 */
static inline unsigned long *bitmap_alloc(int nbits)
{
	return (unsigned long *)calloc(1, BITS_TO_LONGS(nbits) * sizeof(unsigned long));
}

/*
 * bitmap_scnprintf - print bitmap list into buffer
 * @bitmap: bitmap
 * @nbits: size of bitmap
 * @buf: buffer to store output
 * @size: size of @buf
 */
size_t bitmap_scnprintf(unsigned long *bitmap, int nbits,
			char *buf, size_t size);

/**
 * bitmap_and - Do logical and on bitmaps
 * @dst: resulting bitmap
 * @src1: operand 1
 * @src2: operand 2
 * @nbits: size of bitmap
 */
static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
			     const unsigned long *src2, unsigned int nbits)
{
	if (small_const_nbits(nbits))
		return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
	return __bitmap_and(dst, src1, src2, nbits);
}

#endif /* _PERF_BITOPS_H */
