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authorPieter Wuille <pieter.wuille@gmail.com>2012-06-15 15:27:09 +0200
committerPieter Wuille <pieter.wuille@gmail.com>2012-10-20 23:08:56 +0200
commit10fd8604d74a18607a7061500783e384758b02c7 (patch)
tree5564890a276d522b6f01295aaa6e360aefd3030d /src
parent0fa593d0fb3a6f731a31610e98ce6bfd6a50a96c (diff)
downloadbitcoin-10fd8604d74a18607a7061500783e384758b02c7.tar.xz
Add CCoins: pruned list of transaction outputs
The CCoins class represents a pruned set of transaction outputs from a given transaction. It only retains information about its height in the block chain, whether it was a coinbase transaction, and its unspent outputs (script + amount). It has a custom serializer that has very low redundancy.
Diffstat (limited to 'src')
-rw-r--r--src/main.h234
1 files changed, 233 insertions, 1 deletions
diff --git a/src/main.h b/src/main.h
index 4286880c9f..833fd49230 100644
--- a/src/main.h
+++ b/src/main.h
@@ -337,7 +337,7 @@ public:
scriptPubKey.clear();
}
- bool IsNull()
+ bool IsNull() const
{
return (nValue == -1);
}
@@ -673,6 +673,238 @@ public:
});)
};
+/** pruned version of CTransaction: only retains metadata and unspent transaction outputs
+ *
+ * Serialized format:
+ * - VARINT(nVersion)
+ * - VARINT(nCode)
+ * - unspentness bitvector, for vout[2] and further; least significant byte first
+ * - the non-spent CTxOuts (via CTxOutCompressor)
+ * - VARINT(nHeight)
+ *
+ * The nCode value consists of:
+ * - bit 1: IsCoinBase()
+ * - bit 2: vout[0] is not spent
+ * - bit 4: vout[1] is not spent
+ * - The higher bits encode N, the number of non-zero bytes in the following bitvector.
+ * - In case both bit 2 and bit 4 are unset, they encode N-1, as there must be at
+ * least one non-spent output).
+ *
+ * Example: 0104835800816115944e077fe7c803cfa57f29b36bf87c1d358bb85e
+ * <><><--------------------------------------------><---->
+ * | \ | /
+ * version code vout[1] height
+ *
+ * - version = 1
+ * - code = 4 (vout[1] is not spent, and 0 non-zero bytes of bitvector follow)
+ * - unspentness bitvector: as 0 non-zero bytes follow, it has length 0
+ * - vout[1]: 835800816115944e077fe7c803cfa57f29b36bf87c1d35
+ * * 8358: compact amount representation for 60000000000 (600 BTC)
+ * * 00: special txout type pay-to-pubkey-hash
+ * * 816115944e077fe7c803cfa57f29b36bf87c1d35: address uint160
+ * - height = 203998
+ *
+ *
+ * Example: 0109044086ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4eebbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa486af3b
+ * <><><--><--------------------------------------------------><----------------------------------------------><---->
+ * / \ \ | | /
+ * version code unspentness vout[4] vout[16] height
+ *
+ * - version = 1
+ * - code = 9 (coinbase, neither vout[0] or vout[1] are unspent,
+ * 2 (1, +1 because both bit 2 and bit 4 are unset) non-zero bitvector bytes follow)
+ * - unspentness bitvector: bits 2 (0x04) and 14 (0x4000) are set, so vout[2+2] and vout[14+2] are unspent
+ * - vout[4]: 86ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4ee
+ * * 86ef97d579: compact amount representation for 234925952 (2.35 BTC)
+ * * 00: special txout type pay-to-pubkey-hash
+ * * 61b01caab50f1b8e9c50a5057eb43c2d9563a4ee: address uint160
+ * - vout[16]: bbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa4
+ * * bbd123: compact amount representation for 110397 (0.001 BTC)
+ * * 00: special txout type pay-to-pubkey-hash
+ * * 8c988f1a4a4de2161e0f50aac7f17e7f9555caa4: address uint160
+ * - height = 120891
+ */
+class CCoins
+{
+public:
+ // whether transaction is a coinbase
+ bool fCoinBase;
+
+ // unspent transaction outputs; spent outputs are .IsNull(); spent outputs at the end of the array are dropped
+ std::vector<CTxOut> vout;
+
+ // at which height this transaction was included in the active blockchain
+ int nHeight;
+
+ // version of the CTransaction; accesses to this value should probably check for nHeight as well,
+ // as new tx version will probably only be introduced at certain heights
+ int nVersion;
+
+ // construct a CCoins from a CTransaction, at a given height
+ CCoins(const CTransaction &tx, int nHeightIn) : fCoinBase(tx.IsCoinBase()), vout(tx.vout), nHeight(nHeightIn), nVersion(tx.nVersion) { }
+
+ // empty constructor
+ CCoins() : fCoinBase(false), vout(0), nHeight(0), nVersion(0) { }
+
+ // remove spent outputs at the end of vout
+ void Cleanup() {
+ while (vout.size() > 0 && vout.back().IsNull())
+ vout.pop_back();
+ }
+
+ // equality test
+ friend bool operator==(const CCoins &a, const CCoins &b) {
+ return a.fCoinBase == b.fCoinBase &&
+ a.nHeight == b.nHeight &&
+ a.nVersion == b.nVersion &&
+ a.vout == b.vout;
+ }
+ friend bool operator!=(const CCoins &a, const CCoins &b) {
+ return !(a == b);
+ }
+
+ // calculate number of bytes for the bitmask, and its number of non-zero bytes
+ // each bit in the bitmask represents the availability of one output, but the
+ // availabilities of the first two outputs are encoded separately
+ void CalcMaskSize(unsigned int &nBytes, unsigned int &nNonzeroBytes) const {
+ unsigned int nLastUsedByte = 0;
+ for (unsigned int b = 0; 2+b*8 < vout.size(); b++) {
+ bool fZero = true;
+ for (unsigned int i = 0; i < 8 && 2+b*8+i < vout.size(); i++) {
+ if (!vout[2+b*8+i].IsNull()) {
+ fZero = false;
+ continue;
+ }
+ }
+ if (!fZero) {
+ nLastUsedByte = b + 1;
+ nNonzeroBytes++;
+ }
+ }
+ nBytes += nLastUsedByte;
+ }
+
+ bool IsCoinBase() const {
+ return fCoinBase;
+ }
+
+ unsigned int GetSerializeSize(int nType, int nVersion) const {
+ unsigned int nSize = 0;
+ unsigned int nMaskSize = 0, nMaskCode = 0;
+ CalcMaskSize(nMaskSize, nMaskCode);
+ bool fFirst = vout.size() > 0 && !vout[0].IsNull();
+ bool fSecond = vout.size() > 1 && !vout[1].IsNull();
+ assert(fFirst || fSecond || nMaskCode);
+ unsigned int nCode = 8*(nMaskCode - (fFirst || fSecond ? 0 : 1)) + (fCoinBase ? 1 : 0) + (fFirst ? 2 : 0) + (fSecond ? 4 : 0);
+ // version
+ nSize += ::GetSerializeSize(VARINT(this->nVersion), nType, nVersion);
+ // size of header code
+ nSize += ::GetSerializeSize(VARINT(nCode), nType, nVersion);
+ // spentness bitmask
+ nSize += nMaskSize;
+ // txouts themself
+ for (unsigned int i = 0; i < vout.size(); i++)
+ if (!vout[i].IsNull())
+ nSize += ::GetSerializeSize(CTxOutCompressor(REF(vout[i])), nType, nVersion);
+ // height
+ nSize += ::GetSerializeSize(VARINT(nHeight), nType, nVersion);
+ return nSize;
+ }
+
+ template<typename Stream>
+ void Serialize(Stream &s, int nType, int nVersion) const {
+ unsigned int nMaskSize = 0, nMaskCode = 0;
+ CalcMaskSize(nMaskSize, nMaskCode);
+ bool fFirst = vout.size() > 0 && !vout[0].IsNull();
+ bool fSecond = vout.size() > 1 && !vout[1].IsNull();
+ assert(fFirst || fSecond || nMaskCode);
+ unsigned int nCode = 8*(nMaskCode - (fFirst || fSecond ? 0 : 1)) + (fCoinBase ? 1 : 0) + (fFirst ? 2 : 0) + (fSecond ? 4 : 0);
+ // version
+ ::Serialize(s, VARINT(this->nVersion), nType, nVersion);
+ // header code
+ ::Serialize(s, VARINT(nCode), nType, nVersion);
+ // spentness bitmask
+ for (unsigned int b = 0; b<nMaskSize; b++) {
+ unsigned char chAvail = 0;
+ for (unsigned int i = 0; i < 8 && 2+b*8+i < vout.size(); i++)
+ if (!vout[2+b*8+i].IsNull())
+ chAvail |= (1 << i);
+ ::Serialize(s, chAvail, nType, nVersion);
+ }
+ // txouts themself
+ for (unsigned int i = 0; i < vout.size(); i++) {
+ if (!vout[i].IsNull())
+ ::Serialize(s, CTxOutCompressor(REF(vout[i])), nType, nVersion);
+ }
+ // coinbase height
+ ::Serialize(s, VARINT(nHeight), nType, nVersion);
+ }
+
+ template<typename Stream>
+ void Unserialize(Stream &s, int nType, int nVersion) {
+ unsigned int nCode = 0;
+ // version
+ ::Unserialize(s, VARINT(this->nVersion), nType, nVersion);
+ // header code
+ ::Unserialize(s, VARINT(nCode), nType, nVersion);
+ fCoinBase = nCode & 1;
+ std::vector<bool> vAvail(2, false);
+ vAvail[0] = nCode & 2;
+ vAvail[1] = nCode & 4;
+ unsigned int nMaskCode = (nCode / 8) + ((nCode & 6) != 0 ? 0 : 1);
+ // spentness bitmask
+ while (nMaskCode > 0) {
+ unsigned char chAvail = 0;
+ ::Unserialize(s, chAvail, nType, nVersion);
+ for (unsigned int p = 0; p < 8; p++) {
+ bool f = (chAvail & (1 << p)) != 0;
+ vAvail.push_back(f);
+ }
+ if (chAvail != 0)
+ nMaskCode--;
+ }
+ // txouts themself
+ vout.assign(vAvail.size(), CTxOut());
+ for (unsigned int i = 0; i < vAvail.size(); i++) {
+ if (vAvail[i])
+ ::Unserialize(s, REF(CTxOutCompressor(vout[i])), nType, nVersion);
+ }
+ // coinbase height
+ ::Unserialize(s, VARINT(nHeight), nType, nVersion);
+ Cleanup();
+ }
+
+ // mark an outpoint spent
+ bool Spend(const COutPoint &out) {
+ if (out.n >= vout.size())
+ return false;
+ if (vout[out.n].IsNull())
+ return false;
+ vout[out.n].SetNull();
+ Cleanup();
+ return true;
+ }
+
+ // mark a vout spent
+ bool Spend(int nPos) {
+ COutPoint out(0, nPos);
+ return Spend(out);
+ }
+
+ // check whether a particular output is still available
+ bool IsAvailable(unsigned int nPos) const {
+ return (nPos < vout.size() && !vout[nPos].IsNull());
+ }
+
+ // check whether the entire CCoins is spent
+ // note that only !IsPruned() CCoins can be serialized
+ bool IsPruned() const {
+ BOOST_FOREACH(const CTxOut &out, vout)
+ if (!out.IsNull())
+ return false;
+ return true;
+ }
+};