r1

src/bloom.cpp

@@ -0,0 +1,246 @@
+// Copyright (c) 2012-2014 The Bitcoin developers
+// Copyright (c) 2017-2019 The PIVX developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "bloom.h"
+
+
+#include "chainparams.h"
+#include "hash.h"
+#include "libzerocoin/bignum.h"
+#include "libzerocoin/CoinSpend.h"
+#include "primitives/transaction.h"
+#include "script/script.h"
+#include "script/standard.h"
+#include "streams.h"
+
+#include <math.h>
+#include <stdlib.h>
+
+
+#define LN2SQUARED 0.4804530139182014246671025263266649717305529515945455
+#define LN2 0.6931471805599453094172321214581765680755001343602552
+
+using namespace std;
+
+CBloomFilter::CBloomFilter(unsigned int nElements, double nFPRate, unsigned int nTweakIn, unsigned char nFlagsIn) :
+ /**	
+ * The ideal size for a bloom filter with a given number of elements and false positive rate is:
+ * - nElements * log(fp rate) / ln(2)^2
+ * We ignore filter parameters which will create a bloom filter larger than the protocol limits
+ */
+	vData(min((unsigned int)(-1 / LN2SQUARED * nElements * log(nFPRate)), MAX_BLOOM_FILTER_SIZE * 8) / 8),
+ /**
+ * The ideal number of hash functions is filter size * ln(2) / number of elements
+ * Again, we ignore filter parameters which will create a bloom filter with more hash functions than the protocol limits
+ * See https://en.wikipedia.org/wiki/Bloom_filter for an explanation of these formulas
+ */
+	isFull(false),
+	isEmpty(false),
+  nHashFuncs(min((unsigned int)(vData.size() * 8 / nElements * LN2), MAX_HASH_FUNCS)),
+  nTweak(nTweakIn),
+  nFlags(nFlagsIn)
+{
+}
+
+inline unsigned int CBloomFilter::Hash(unsigned int nHashNum, const std::vector<unsigned char>& vDataToHash) const
+{
+    // 0xFBA4C795 chosen as it guarantees a reasonable bit difference between nHashNum values.
+    return MurmurHash3(nHashNum * 0xFBA4C795 + nTweak, vDataToHash) % (vData.size() * 8);
+}
+
+void CBloomFilter::setNotFull()
+{
+    isFull = false;
+}
+
+void CBloomFilter::insert(const vector<unsigned char>& vKey)
+{
+    if (isFull)
+        return;
+    for (unsigned int i = 0; i < nHashFuncs; i++) {
+        unsigned int nIndex = Hash(i, vKey);
+        // Sets bit nIndex of vData
+        vData[nIndex >> 3] |= (1 << (7 & nIndex));
+    }
+    isEmpty = false;
+}
+
+void CBloomFilter::insert(const COutPoint& outpoint)
+{
+    CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
+    stream << outpoint;
+    vector<unsigned char> data(stream.begin(), stream.end());
+    insert(data);
+}
+
+void CBloomFilter::insert(const uint256& hash)
+{
+    vector<unsigned char> data(hash.begin(), hash.end());
+    insert(data);
+}
+
+bool CBloomFilter::contains(const vector<unsigned char>& vKey) const
+{
+    if (isFull) {
+        return true;
+    }
+    if (isEmpty) {
+        return false;
+    }
+    for (unsigned int i = 0; i < nHashFuncs; i++) {
+        unsigned int nIndex = Hash(i, vKey);
+        // Checks bit nIndex of vData
+        if (!(vData[nIndex >> 3] & (1 << (7 & nIndex))))
+            return false;
+    }
+    return true;
+}
+
+bool CBloomFilter::contains(const COutPoint& outpoint) const
+{
+    CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
+    stream << outpoint;
+    vector<unsigned char> data(stream.begin(), stream.end());
+    return contains(data);
+}
+
+bool CBloomFilter::contains(const uint256& hash) const
+{
+    vector<unsigned char> data(hash.begin(), hash.end());
+    return contains(data);
+}
+
+void CBloomFilter::clear()
+{
+    vData.assign(vData.size(), 0);
+    isFull = false;
+    isEmpty = true;
+}
+
+bool CBloomFilter::IsWithinSizeConstraints() const
+{
+    return vData.size() <= MAX_BLOOM_FILTER_SIZE && nHashFuncs <= MAX_HASH_FUNCS;
+}
+
+/**
+ * Returns true if this filter will match anything. See {@link org.agrarianj.core.BloomFilter#setMatchAll()}
+ * for when this can be a useful thing to do.
+ */
+bool CBloomFilter::MatchesAll() const {
+    for (unsigned char b : vData)
+        if (b !=  0xff)
+            return false;
+    return true;
+}
+
+/**
+ * Copies filter into this. Filter must have the same size, hash function count and nTweak or an
+ * IllegalArgumentException will be thrown.
+ */
+bool CBloomFilter::Merge(const CBloomFilter& filter) {
+    if (!this->MatchesAll() && !filter.MatchesAll()) {
+        if(! (filter.vData.size() == this->vData.size() &&
+                filter.nHashFuncs == this->nHashFuncs &&
+                filter.nTweak == this->nTweak)){
+            return false;
+        }
+        for (unsigned int i = 0; i < vData.size(); i++)
+            this->vData[i] |= filter.vData[i];
+    } else {
+        // TODO: Check this.
+        this->vData.clear();
+        this->vData[0] = 0xff;
+    }
+    return true;
+}
+
+bool CBloomFilter::IsRelevantAndUpdate(const CTransaction& tx)
+{
+    bool fFound = false;
+    // Match if the filter contains the hash of tx
+    //  for finding tx when they appear in a block
+    if (isFull)
+        return true;
+    if (isEmpty)
+        return false;
+    const uint256& hash = tx.GetHash();
+    if (contains(hash))
+        fFound = true;
+
+    for (unsigned int i = 0; i < tx.vout.size(); i++) {
+        const CTxOut& txout = tx.vout[i];
+        // Match if the filter contains any arbitrary script data element in any scriptPubKey in tx
+        // If this matches, also add the specific output that was matched.
+        // This means clients don't have to update the filter themselves when a new relevant tx
+        // is discovered in order to find spending transactions, which avoids round-tripping and race conditions.
+        CScript::const_iterator pc = txout.scriptPubKey.begin();
+        vector<unsigned char> data;
+        while (pc < txout.scriptPubKey.end()) {
+            opcodetype opcode;
+            if (!txout.scriptPubKey.GetOp(pc, opcode, data)){
+                break;
+            }
+
+            if (txout.IsZerocoinMint()){
+                data = vector<unsigned char>(txout.scriptPubKey.begin() + 6, txout.scriptPubKey.begin() + txout.scriptPubKey.size());
+            }
+
+            if (data.size() != 0 && contains(data)) {
+                fFound = true;
+                if ((nFlags & BLOOM_UPDATE_MASK) == BLOOM_UPDATE_ALL)
+                    insert(COutPoint(hash, i));
+                else if ((nFlags & BLOOM_UPDATE_MASK) == BLOOM_UPDATE_P2PUBKEY_ONLY) {
+                    txnouttype type;
+                    vector<vector<unsigned char> > vSolutions;
+                    if (Solver(txout.scriptPubKey, type, vSolutions) &&
+                        (type == TX_PUBKEY || type == TX_MULTISIG))
+                        insert(COutPoint(hash, i));
+                }
+                break;
+            }
+        }
+    }
+
+    if (fFound)
+        return true;
+
+    for (const CTxIn& txin : tx.vin) {
+        // Match if the filter contains an outpoint tx spends
+        if (contains(txin.prevout))
+            return true;
+
+        // Match if the filter contains any arbitrary script data element in any scriptSig in tx
+        CScript::const_iterator pc = txin.scriptSig.begin();
+        vector<unsigned char> data;
+        while (pc < txin.scriptSig.end()) {
+            opcodetype opcode;
+            if (!txin.scriptSig.GetOp(pc, opcode, data))
+                break;
+            if (txin.IsZerocoinSpend()) {
+                CDataStream s(vector<unsigned char>(txin.scriptSig.begin() + 44, txin.scriptSig.end()),
+                        SER_NETWORK, PROTOCOL_VERSION);
+
+                data = libzerocoin::CoinSpend::ParseSerial(s);
+            }
+            if (data.size() != 0 && contains(data)) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+void CBloomFilter::UpdateEmptyFull()
+{
+    bool full = true;
+    bool empty = true;
+    for (unsigned int i = 0; i < vData.size(); i++) {
+        full &= vData[i] == 0xff;
+        empty &= vData[i] == 0;
+    }
+    isFull = full;
+    isEmpty = empty;
+}