flexnbd-c/bitset.h

#ifndef __BITSET_H
#define __BITSET_H

#include <inttypes.h>
#include <string.h>

static inline char char_with_bit_set(int num) { return 1<<(num%8); }

static inline int bit_is_set(char* b, int idx) {
	return (b[idx/8] & char_with_bit_set(idx)) != 0;
}
static inline int bit_is_clear(char* b, int idx) {
	return !bit_is_set(b, idx);
}
static inline int bit_has_value(char* b, int idx, int value) {
	if (value)
		return bit_is_set(b, idx);
	else
		return bit_is_clear(b, idx);
}
static inline void bit_set(char* b, int idx) {
	b[idx/8] |= char_with_bit_set(idx);
}
static inline void bit_clear(char* b, int idx) {
	b[idx/8] &= ~char_with_bit_set(idx);
}
static inline void bit_set_range(char* b, int from, int len) {
	for (; from%8 != 0 && len > 0; len--)
		bit_set(b, from++);
	if (len >= 8)
		memset(b+(from/8), 255, len/8);
	for (; len > 0; len--)
		bit_set(b, from++);
}
static inline void bit_clear_range(char* b, int from, int len) {
	for (; from%8 != 0 && len > 0; len--)
		bit_clear(b, from++);
	if (len >= 8)
		memset(b+(from/8), 0, len/8);
	for (; len > 0; len--)
		bit_clear(b, from++);
}

static inline int bit_run_count(char* b, int from, int len) {
	int count;
	int first_value = bit_is_set(b, from);

	for (count=0; len > 0 && bit_has_value(b, from+count, first_value); count++, len--)
		;

	/* FIXME: debug this later */
	/*for (; (from+count) % 64 != 0 && len > 0; len--)
		if (bit_has_value(b, from+count, first_value))
			count++;
		else
			return count;
	for (; len >= 64; len-=64) {
		if (*((uint64_t*)(b + ((from+count)/8))) == UINT64_MAX)
			count += 64;
		else
			break;
	}
	for (; len > 0; len--)
		if (bit_is_set(b, from+count))
			count++;*/

	return count;
}

#endif