bloom.h

Go to the documentation of this file.

// Copyright (c) 2012-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_COMMON_BLOOM_H
#define BITCOIN_COMMON_BLOOM_H

#include <serialize.h>
#include <span.h>

#include <vector>

class COutPoint;
class CTransaction;

static constexpr unsigned int MAX_BLOOM_FILTER_SIZE = 36000; // bytes
static constexpr unsigned int MAX_HASH_FUNCS = 50;

enum bloomflags
{
    BLOOM_UPDATE_NONE = 0,
    BLOOM_UPDATE_ALL = 1,
    // Only adds outpoints to the filter if the output is a pay-to-pubkey/pay-to-multisig script
    BLOOM_UPDATE_P2PUBKEY_ONLY = 2,
    BLOOM_UPDATE_MASK = 3,
};

class CBloomFilter
{
private:
    std::vector<unsigned char> vData;
    unsigned int nHashFuncs;
    unsigned int nTweak;
    unsigned char nFlags;

    unsigned int Hash(unsigned int nHashNum, std::span<const unsigned char> vDataToHash) const;

public:
    CBloomFilter(unsigned int nElements, double nFPRate, unsigned int nTweak, unsigned char nFlagsIn);
    CBloomFilter() : nHashFuncs(0), nTweak(0), nFlags(0) {}

    SERIALIZE_METHODS(CBloomFilter, obj) { READWRITE(obj.vData, obj.nHashFuncs, obj.nTweak, obj.nFlags); }

    void insert(std::span<const unsigned char> vKey);
    void insert(const COutPoint& outpoint);

    bool contains(std::span<const unsigned char> vKey) const;
    bool contains(const COutPoint& outpoint) const;

    bool IsWithinSizeConstraints() const;

    bool IsRelevantAndUpdate(const CTransaction& tx);
};

class CRollingBloomFilter
{
public:
    CRollingBloomFilter(unsigned int nElements, double nFPRate);

    void insert(std::span<const unsigned char> vKey);
    bool contains(std::span<const unsigned char> vKey) const;

    void reset();

private:
    int nEntriesPerGeneration;
    int nEntriesThisGeneration;
    int nGeneration;
    std::vector<uint64_t> data;
    unsigned int nTweak;
    int nHashFuncs;
};

#endif // BITCOIN_COMMON_BLOOM_H