bloom.h

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// Copyright (c) 2012-2015 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_BLOOM_H
#define BITCOIN_BLOOM_H

#include <serialize.h>

#include <vector>

class COutPoint;
class CScript;
class CTransaction;
class uint256;
class uint160;

static const unsigned int MAX_BLOOM_FILTER_SIZE = 36000; // bytes
static const 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;
    bool isFull;
    bool isEmpty;
    unsigned int nHashFuncs;
    unsigned int nTweak;
    unsigned char nFlags;

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

    // Private constructor for CRollingBloomFilter, no restrictions on size
    CBloomFilter(const unsigned int nElements, const double nFPRate, const unsigned int nTweak);
    friend class CRollingBloomFilter;

    // Check matches for arbitrary script data elements
    bool CheckScript(const CScript& script) const;
    // Check additional matches for special transactions
    bool CheckSpecialTransactionMatchesAndUpdate(const CTransaction& tx);
public:
    CBloomFilter(const unsigned int nElements, const double nFPRate, const unsigned int nTweak, unsigned char nFlagsIn);
    CBloomFilter() : isFull(true), isEmpty(false), nHashFuncs(0), nTweak(0), nFlags(0) {}

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        READWRITE(vData);
        READWRITE(nHashFuncs);
        READWRITE(nTweak);
        READWRITE(nFlags);
    }

    void insert(const std::vector<unsigned char>& vKey);
    void insert(const COutPoint& outpoint);
    void insert(const uint256& hash);

    bool contains(const std::vector<unsigned char>& vKey) const;
    bool contains(const COutPoint& outpoint) const;
    bool contains(const uint256& hash) const;
    bool contains(const uint160& hash) const;

    void clear();
    void reset(const unsigned int nNewTweak);

    bool IsWithinSizeConstraints() const;

    bool IsRelevantAndUpdate(const CTransaction& tx);

    void UpdateEmptyFull();
};

class CRollingBloomFilter
{
public:
    // A random bloom filter calls GetRand() at creation time.
    // Don't create global CRollingBloomFilter objects, as they may be
    // constructed before the randomizer is properly initialized.
    CRollingBloomFilter(const unsigned int nElements, const double nFPRate);

    void insert(const std::vector<unsigned char>& vKey);
    void insert(const uint256& hash);
    bool contains(const std::vector<unsigned char>& vKey) const;
    bool contains(const uint256& hash) const;

    void reset();

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

#endif // BITCOIN_BLOOM_H