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/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
*
* This file is released under the LGPL.
*/
#include "bitset.h"
#include "dbg_malloc.h"
#include <stdlib.h>
/* FIXME: calculate this. */
#define INT_SHIFT 5
bitset_t bitset_create(struct pool *mem, unsigned num_bits)
{
int n = (num_bits / BITS_PER_INT) + 2;
int size = sizeof(int) * n;
unsigned *bs = pool_zalloc(mem, size);
if (!bs)
return NULL;
*bs = num_bits;
return bs;
}
void bitset_destroy(bitset_t bs)
{
dbg_free(bs);
}
void bit_union(bitset_t out, bitset_t in1, bitset_t in2)
{
int i;
for(i = (in1[0] / BITS_PER_INT) + 1; i; i--)
out[i] = in1[i] | in2[i];
}
/*
* FIXME: slow
*/
static inline int _test_word(uint32_t test, int bit)
{
while (bit < BITS_PER_INT) {
if (test & (0x1 << bit))
return bit;
bit++;
}
return -1;
}
int bit_get_next(bitset_t bs, int last_bit)
{
int bit, word;
uint32_t test;
last_bit++; /* otherwise we'll return the same bit again */
while(last_bit < bs[0]) {
word = last_bit >> INT_SHIFT;
test = bs[word + 1];
bit = last_bit & (BITS_PER_INT - 1);
if ((bit = _test_word(test, bit)) >= 0)
return (word * BITS_PER_INT) + bit;
last_bit = last_bit - (last_bit & (BITS_PER_INT - 1)) +
BITS_PER_INT;
}
return -1;
}
int bit_get_first(bitset_t bs)
{
return bit_get_next(bs, -1);
}
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