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Also switch BloomFilters from H3 to siphash.

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This removes all dependencies on H3 in our source tree.
This commit is contained in:
Johanna Amann 2016-07-13 09:04:10 -07:00
parent e1218cc7fa
commit f1bae871e9
8 changed files with 78 additions and 178 deletions
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39
src/probabilistic/Hasher.h
View file

@ -4,7 +4,6 @@
#define PROBABILISTIC_HASHER_H
#include "Hash.h"
#include "H3.h"
#include "SerialObj.h"
namespace probabilistic {
@ -17,6 +16,15 @@ class Hasher : public SerialObj {
public:
typedef hash_t digest;
typedef std::vector<digest> digest_vector;
struct seed_t {
uint64_t h1;
uint64_t h2;
friend seed_t operator+(seed_t lhs, const uint64_t rhs) {
lhs.h1 += rhs;
return lhs;
}
};
/**
* Creates a valid hasher seed from an arbitrary string.
@ -30,7 +38,7 @@ public:
*
* @return A seed suitable for hashers.
*/
static uint64 MakeSeed(const void* data, size_t size);
static seed_t MakeSeed(const void* data, size_t size);
/**
* Destructor.
@ -89,7 +97,7 @@ public:
/**
* Returns the seed used to construct the hasher.
*/
size_t Seed() const { return seed; }
seed_t Seed() const { return seed; }
bool Serialize(SerialInfo* info) const;
static Hasher* Unserialize(UnserialInfo* info);
@ -106,11 +114,11 @@ protected:
*
* @param arg_seed The seed for the hasher.
*/
Hasher(size_t arg_k, size_t arg_seed);
Hasher(size_t arg_k, seed_t arg_seed);
private:
size_t k;
size_t seed;
seed_t seed;
};
/**
@ -120,12 +128,17 @@ private:
class UHF {
public:
/**
* Constructs an H3 hash function seeded with a given seed and an
* Default constructor with zero seed.
*/
UHF();
/**
* Constructs an hash function seeded with a given seed and an
* optional extra seed to replace the initial Bro seed.
*
* @param arg_seed The seed to use for this instance.
*/
UHF(size_t arg_seed = 0);
UHF(Hasher::seed_t arg_seed);
template <typename T>
Hasher::digest operator()(const T& x) const
@ -159,7 +172,8 @@ public:
friend bool operator==(const UHF& x, const UHF& y)
{
return x.h == y.h;
return (x.seed.h1 == y.seed.h1) &&
(x.seed.h2 == y.seed.h2);
}
friend bool operator!=(const UHF& x, const UHF& y)
@ -168,10 +182,9 @@ public:
}
private:
static size_t compute_seed(size_t seed);
static size_t compute_seed(Hasher::seed_t seed);
H3<Hasher::digest, UHASH_KEY_SIZE> h;
size_t seed;
Hasher::seed_t seed;
};
@ -188,7 +201,7 @@ public:
*
* @param seed The seed for the hasher.
*/
DefaultHasher(size_t k, size_t seed);
DefaultHasher(size_t k, Hasher::seed_t seed);
// Overridden from Hasher.
virtual digest_vector Hash(const void* x, size_t n) const final;
@ -216,7 +229,7 @@ public:
*
* @param seed The seed for the hasher.
*/
DoubleHasher(size_t k, size_t seed);
DoubleHasher(size_t k, Hasher::seed_t seed);
// Overridden from Hasher.
virtual digest_vector Hash(const void* x, size_t n) const final;