#include "siphash24.h"
#include "bus-bloom.h"
-static inline void set_bit(uint64_t filter[], unsigned b) {
+static inline void set_bit(uint64_t filter[], unsigned long b) {
filter[b >> 6] |= 1ULL << (b & 63);
}
-#define HASH_KEY1 SD_ID128_MAKE(b9,66,0b,f0,46,70,47,c1,88,75,c4,9c,54,b9,bd,15)
-#define HASH_KEY2 SD_ID128_MAKE(aa,a1,54,a2,e0,71,4b,39,bf,e1,dd,2e,9f,c5,4a,3b)
-
-static void bloom_add_data(uint64_t filter[BLOOM_SIZE/8], const void *data, size_t n) {
- uint8_t a[8], b[8];
- unsigned k = 0;
-
- /*
- * Our bloom filter has the following parameters:
- *
- * m=512 (bits in the filter)
- * k=8 (hash functions)
- *
- * We calculate a two 64bit SipHash values (for two fixed but
- * randomly generated hash keys) of which we use 8 parts of 9 bits
- * as individual hash functions.
- *
- */
-
- siphash24(a, data, n, HASH_KEY1.bytes);
- siphash24(b, data, n, HASH_KEY2.bytes);
-
- assert_cc(BLOOM_SIZE*8 == 512);
-
- for (k = 0; k < 8; k++)
- set_bit(filter, ((uint16_t) a[k] << 1) ^ (uint16_t) b[k]);
+static const sd_id128_t hash_keys[] = {
+ SD_ID128_ARRAY(b9,66,0b,f0,46,70,47,c1,88,75,c4,9c,54,b9,bd,15),
+ SD_ID128_ARRAY(aa,a1,54,a2,e0,71,4b,39,bf,e1,dd,2e,9f,c5,4a,3b),
+ SD_ID128_ARRAY(63,fd,ae,be,cd,82,48,12,a1,6e,41,26,cb,fa,a0,c8),
+ SD_ID128_ARRAY(23,be,45,29,32,d2,46,2d,82,03,52,28,fe,37,17,f5),
+ SD_ID128_ARRAY(56,3b,bf,ee,5a,4f,43,39,af,aa,94,08,df,f0,fc,10),
+ SD_ID128_ARRAY(31,80,c8,73,c7,ea,46,d3,aa,25,75,0f,9e,4c,09,29),
+ SD_ID128_ARRAY(7d,f7,18,4b,7b,a4,44,d5,85,3c,06,e0,65,53,96,6d),
+ SD_ID128_ARRAY(f2,77,e9,6f,93,b5,4e,71,9a,0c,34,88,39,25,bf,35),
+};
+
+static void bloom_add_data(
+ uint64_t filter[], /* The filter bits */
+ size_t size, /* Size of the filter in bytes */
+ unsigned k, /* Number of hash functions */
+ const void *data, /* Data to hash */
+ size_t n) { /* Size of data to hash in bytes */
+
+ uint8_t h[8];
+ uint64_t m;
+ unsigned w, i, c = 0;
+ unsigned hash_index;
+
+ assert(size > 0);
+ assert(k > 0);
+
+ /* Determine bits in filter */
+ m = size * 8;
+
+ /* Determine how many bytes we need to generate a bit index 0..m for this filter */
+ w = (u64log2(m) + 7) / 8;
+
+ assert(w <= sizeof(uint64_t));
+
+ /* Make sure we have enough hash keys to generate m * k bits
+ * of hash value. Note that SipHash24 generates 64 bits of
+ * hash value for each 128 bits of hash key. */
+ assert(k * w <= ELEMENTSOF(hash_keys) * 8);
+
+ for (i = 0, hash_index = 0; i < k; i++) {
+ uint64_t p = 0;
+ unsigned d;
+
+ for (d = 0; d < w; d++) {
+ if (c <= 0) {
+ siphash24(h, data, n, hash_keys[hash_index++].bytes);
+ c += 8;
+ }
+
+ p = (p << 8ULL) | (uint64_t) h[8 - c];
+ c--;
+ }
+
+ p &= m - 1;
+ set_bit(filter, p);
+ }
/* log_debug("bloom: adding <%.*s>", (int) n, (char*) data); */
}
-void bloom_add_pair(uint64_t filter[BLOOM_SIZE/8], const char *a, const char *b) {
+void bloom_add_pair(uint64_t filter[], size_t size, unsigned k, const char *a, const char *b) {
size_t n;
char *c;
c = alloca(n + 1);
strcpy(stpcpy(stpcpy(c, a), ":"), b);
- bloom_add_data(filter, c, n);
+ bloom_add_data(filter, size, k, c, n);
}
-void bloom_add_prefixes(uint64_t filter[BLOOM_SIZE/8], const char *a, const char *b, char sep) {
+void bloom_add_prefixes(uint64_t filter[], size_t size, unsigned k, const char *a, const char *b, char sep) {
size_t n;
char *c, *p;
break;
*e = 0;
- bloom_add_data(filter, c, e - c);
+ bloom_add_data(filter, size, k, c, e - c);
}
}
+
+bool bloom_validate_parameters(size_t size, unsigned k) {
+ uint64_t m;
+ unsigned w;
+
+ if (size <= 0)
+ return false;
+
+ if (k <= 0)
+ return false;
+
+ m = size * 8;
+ w = (u64log2(m) + 7) / 8;
+ if (w > sizeof(uint64_t))
+ return false;
+
+ if (k * w > ELEMENTSOF(hash_keys) * 8)
+ return false;
+
+ return true;
+}
~ianmdlvl / elogind.git / blobdiff