+#include <stdlib.h>
+#include <inttypes.h>
+
+#include "bloom.h"
+#include "../hash.h"
+
+struct bloom {
+ uint64_t nentries;
+
+ uint32_t *map;
+};
+
+#define BITS_PER_INDEX (sizeof(uint32_t) * 8)
+#define BITS_INDEX_MASK (BITS_PER_INDEX - 1)
+
+static unsigned int jhash_init[] = { 0, 0x12db635, 0x2a4a53 };
+#define N_HASHES 3
+
+struct bloom *bloom_new(uint64_t entries)
+{
+ struct bloom *b;
+ size_t no_uints;
+
+ b = malloc(sizeof(*b));
+ b->nentries = entries;
+ no_uints = (entries + BITS_PER_INDEX - 1) / BITS_PER_INDEX;
+ b->map = calloc(no_uints, sizeof(uint32_t));
+ if (!b->map) {
+ free(b);
+ return NULL;
+ }
+
+ return b;
+}
+
+void bloom_free(struct bloom *b)
+{
+ free(b->map);
+ free(b);
+}
+
+static int __bloom_check(struct bloom *b, uint32_t *data, unsigned int nwords,
+ int set)
+{
+ uint32_t hashes[N_HASHES];
+ int i, was_set;
+
+ for (i = 0; i < N_HASHES; i++)
+ hashes[i] = jhash(data, nwords, jhash_init[i]) % b->nentries;
+
+ was_set = 0;
+ for (i = 0; i < N_HASHES; i++) {
+ const unsigned int index = hashes[i] / BITS_PER_INDEX;
+ const unsigned int bit = hashes[i] & BITS_INDEX_MASK;
+
+ if (b->map[index] & (1U << bit))
+ was_set++;
+ if (set)
+ b->map[index] |= 1U << bit;
+ }
+
+ return was_set == N_HASHES;
+}
+
+int bloom_check(struct bloom *b, uint32_t *data, unsigned int nwords)
+{
+ return __bloom_check(b, data, nwords, 0);
+}
+
+int bloom_set(struct bloom *b, uint32_t *data, unsigned int nwords)
+{
+ return __bloom_check(b, data, nwords, 1);
+}