3d796f8996
The implementation of each class' serialization/deserialization is no longer
passed within a macro. The implementation now lies within a template of form:
template <typename T, typename Stream, typename Operation>
inline static size_t SerializationOp(T thisPtr, Stream& s, Operation ser_action, int nType, int nVersion) {
size_t nSerSize = 0;
/* CODE */
return nSerSize;
}
In cases when codepath should depend on whether or not we are just deserializing
(old fGetSize, fWrite, fRead flags) an additional clause can be used:
bool fRead = boost::is_same<Operation, CSerActionUnserialize>();
The IMPLEMENT_SERIALIZE macro will now be a freestanding clause added within
class' body (similiar to Qt's Q_OBJECT) to implement GetSerializeSize,
Serialize and Unserialize. These are now wrappers around
the "SerializationOp" template.
99 lines
3.6 KiB
C++
99 lines
3.6 KiB
C++
// Copyright (c) 2012 The Bitcoin developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_BLOOM_H
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#define BITCOIN_BLOOM_H
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#include "serialize.h"
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#include <vector>
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class COutPoint;
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class CTransaction;
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class uint256;
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// 20,000 items with fp rate < 0.1% or 10,000 items and <0.0001%
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static const unsigned int MAX_BLOOM_FILTER_SIZE = 36000; // bytes
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static const unsigned int MAX_HASH_FUNCS = 50;
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// First two bits of nFlags control how much IsRelevantAndUpdate actually updates
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// The remaining bits are reserved
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enum bloomflags
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{
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BLOOM_UPDATE_NONE = 0,
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BLOOM_UPDATE_ALL = 1,
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// Only adds outpoints to the filter if the output is a pay-to-pubkey/pay-to-multisig script
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BLOOM_UPDATE_P2PUBKEY_ONLY = 2,
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BLOOM_UPDATE_MASK = 3,
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};
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/**
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* BloomFilter is a probabilistic filter which SPV clients provide
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* so that we can filter the transactions we sends them.
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*
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* This allows for significantly more efficient transaction and block downloads.
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*
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* Because bloom filters are probabilistic, an SPV node can increase the false-
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* positive rate, making us send them transactions which aren't actually theirs,
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* allowing clients to trade more bandwidth for more privacy by obfuscating which
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* keys are owned by them.
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*/
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class CBloomFilter
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{
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private:
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std::vector<unsigned char> vData;
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bool isFull;
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bool isEmpty;
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unsigned int nHashFuncs;
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unsigned int nTweak;
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unsigned char nFlags;
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unsigned int Hash(unsigned int nHashNum, const std::vector<unsigned char>& vDataToHash) const;
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public:
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// Creates a new bloom filter which will provide the given fp rate when filled with the given number of elements
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// Note that if the given parameters will result in a filter outside the bounds of the protocol limits,
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// the filter created will be as close to the given parameters as possible within the protocol limits.
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// This will apply if nFPRate is very low or nElements is unreasonably high.
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// nTweak is a constant which is added to the seed value passed to the hash function
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// It should generally always be a random value (and is largely only exposed for unit testing)
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// nFlags should be one of the BLOOM_UPDATE_* enums (not _MASK)
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CBloomFilter(unsigned int nElements, double nFPRate, unsigned int nTweak, unsigned char nFlagsIn);
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CBloomFilter() : isFull(true), isEmpty(false), nHashFuncs(0), nTweak(0), nFlags(0) {}
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IMPLEMENT_SERIALIZE
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template <typename T, typename Stream, typename Operation>
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inline static size_t SerializationOp(T thisPtr, Stream& s, Operation ser_action, int nType, int nVersion) {
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size_t nSerSize = 0;
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READWRITE(thisPtr->vData);
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READWRITE(thisPtr->nHashFuncs);
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READWRITE(thisPtr->nTweak);
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READWRITE(thisPtr->nFlags);
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return nSerSize;
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}
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void insert(const std::vector<unsigned char>& vKey);
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void insert(const COutPoint& outpoint);
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void insert(const uint256& hash);
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bool contains(const std::vector<unsigned char>& vKey) const;
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bool contains(const COutPoint& outpoint) const;
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bool contains(const uint256& hash) const;
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void clear();
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// True if the size is <= MAX_BLOOM_FILTER_SIZE and the number of hash functions is <= MAX_HASH_FUNCS
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// (catch a filter which was just deserialized which was too big)
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bool IsWithinSizeConstraints() const;
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// Also adds any outputs which match the filter to the filter (to match their spending txes)
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bool IsRelevantAndUpdate(const CTransaction& tx);
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// Checks for empty and full filters to avoid wasting cpu
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void UpdateEmptyFull();
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};
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#endif /* BITCOIN_BLOOM_H */
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