bloom.h

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// Copyright (c) 2012-2016 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 <cstdint>
#include <vector>
 
class COutPoint;
class CTransaction;
 
static const uint32_t MAX_BLOOM_FILTER_SIZE = 36000; // bytes
static const uint32_t 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<uint8_t> vData;
    uint32_t nHashFuncs;
    uint32_t nTweak;
    uint8_t nFlags;
 
    uint32_t Hash(uint32_t nHashNum, Span<const uint8_t> vDataToHash) const;
 
public:
    CBloomFilter(const uint32_t nElements, const double nFPRate,
                 const uint32_t nTweak, uint8_t nFlagsIn);
    CBloomFilter() : nHashFuncs(0), nTweak(0), nFlags(0) {}
 
    SERIALIZE_METHODS(CBloomFilter, obj) {
        READWRITE(obj.vData, obj.nHashFuncs, obj.nTweak, obj.nFlags);
    }
 
    void insert(Span<const uint8_t> vKey);
    void insert(const COutPoint &outpoint);
 
    bool contains(Span<const uint8_t> vKey) const;
    bool contains(const COutPoint &outpoint) const;
 
    bool IsWithinSizeConstraints() const;
 
    bool MatchAndInsertOutputs(const CTransaction &tx);
 
    bool MatchInputs(const CTransaction &tx);
 
    bool IsRelevantAndUpdate(const CTransaction &tx) {
        return MatchAndInsertOutputs(tx) || MatchInputs(tx);
    }
};
 
class CRollingBloomFilter {
public:
    CRollingBloomFilter(const uint32_t nElements, const double nFPRate);
 
    void insert(Span<const uint8_t> vKey);
    bool contains(Span<const uint8_t> vKey) const;
 
    void reset();
 
private:
    int nEntriesPerGeneration;
    int nEntriesThisGeneration;
    int nGeneration;
    std::vector<uint64_t> data;
    uint32_t nTweak;
    int nHashFuncs;
};
 
#endif // BITCOIN_COMMON_BLOOM_H