68 lines
1.2 KiB
C
68 lines
1.2 KiB
C
#include <arpa/inet.h> /* For htonl() */
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#include <math.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "bhash.h"
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void bhash_init(bhash_t *bh, const void *data, size_t data_len)
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{
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memset(bh, 0, sizeof(*bh));
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bh->bh_data = malloc(data_len);
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memcpy(bh->bh_data, data, data_len);
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bh->bh_len = data_len;
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bh->bh_bits_avail = data_len * 8.0;
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}
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void bhash_fini(bhash_t *bh)
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{
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free(bh->bh_data);
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}
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uint32_t bhash_mod32(bhash_t *bh, uint32_t mod)
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{
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uint32_t *pi;
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uint32_t *pend;
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uint64_t n;
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uint32_t rv = 0;
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if ((bh->bh_len % sizeof(uint32_t)) != 0)
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{
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return BHASH_MOD32_ERR;
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}
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pend = (uint32_t *)(bh->bh_data + bh->bh_len);
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for (pi = (uint32_t *)bh->bh_data; pi < pend; pi++)
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{
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n = (uint64_t)rv << (sizeof(uint32_t) * 8);
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n |= htonl(*pi);
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*pi = ntohl(n / mod);
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rv = n % mod;
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}
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bh->bh_bits_used += log(mod) / log(2);
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if (bh->bh_bits_used > bh->bh_bits_avail)
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{
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return BHASH_MOD32_ERR;
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}
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return rv;
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}
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double bhash_bits_avail(bhash_t *bh)
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{
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return bh->bh_bits_avail;
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}
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double bhash_bits_used(bhash_t *bh)
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{
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return bh->bh_bits_used;
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}
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