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+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef H_BITCOIN_CHAIN
+#define H_BITCOIN_CHAIN
+
+#include "core.h"
+#include "pow.h"
+#include "uint256.h"
+
+#include <vector>
+
+#include <boost/foreach.hpp>
+
+struct CDiskBlockPos
+{
+ int nFile;
+ unsigned int nPos;
+
+ ADD_SERIALIZE_METHODS;
+
+ template <typename Stream, typename Operation>
+ inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+ READWRITE(VARINT(nFile));
+ READWRITE(VARINT(nPos));
+ }
+
+ CDiskBlockPos() {
+ SetNull();
+ }
+
+ CDiskBlockPos(int nFileIn, unsigned int nPosIn) {
+ nFile = nFileIn;
+ nPos = nPosIn;
+ }
+
+ friend bool operator==(const CDiskBlockPos &a, const CDiskBlockPos &b) {
+ return (a.nFile == b.nFile && a.nPos == b.nPos);
+ }
+
+ friend bool operator!=(const CDiskBlockPos &a, const CDiskBlockPos &b) {
+ return !(a == b);
+ }
+
+ void SetNull() { nFile = -1; nPos = 0; }
+ bool IsNull() const { return (nFile == -1); }
+};
+
+enum BlockStatus {
+ BLOCK_VALID_UNKNOWN = 0,
+ BLOCK_VALID_HEADER = 1, // parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future
+ BLOCK_VALID_TREE = 2, // parent found, difficulty matches, timestamp >= median previous, checkpoint
+ BLOCK_VALID_TRANSACTIONS = 3, // only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids, sigops, size, merkle root
+ BLOCK_VALID_CHAIN = 4, // outputs do not overspend inputs, no double spends, coinbase output ok, immature coinbase spends, BIP30
+ BLOCK_VALID_SCRIPTS = 5, // scripts/signatures ok
+ BLOCK_VALID_MASK = BLOCK_VALID_HEADER | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS |
+ BLOCK_VALID_CHAIN | BLOCK_VALID_SCRIPTS,
+
+ BLOCK_HAVE_DATA = 8, // full block available in blk*.dat
+ BLOCK_HAVE_UNDO = 16, // undo data available in rev*.dat
+ BLOCK_HAVE_MASK = BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO,
+
+ BLOCK_FAILED_VALID = 32, // stage after last reached validness failed
+ BLOCK_FAILED_CHILD = 64, // descends from failed block
+ BLOCK_FAILED_MASK = BLOCK_FAILED_VALID | BLOCK_FAILED_CHILD,
+};
+
+/** The block chain is a tree shaped structure starting with the
+ * genesis block at the root, with each block potentially having multiple
+ * candidates to be the next block. A blockindex may have multiple pprev pointing
+ * to it, but at most one of them can be part of the currently active branch.
+ */
+class CBlockIndex
+{
+public:
+ // pointer to the hash of the block, if any. memory is owned by this CBlockIndex
+ const uint256* phashBlock;
+
+ // pointer to the index of the predecessor of this block
+ CBlockIndex* pprev;
+
+ // pointer to the index of some further predecessor of this block
+ CBlockIndex* pskip;
+
+ // height of the entry in the chain. The genesis block has height 0
+ int nHeight;
+
+ // Which # file this block is stored in (blk?????.dat)
+ int nFile;
+
+ // Byte offset within blk?????.dat where this block's data is stored
+ unsigned int nDataPos;
+
+ // Byte offset within rev?????.dat where this block's undo data is stored
+ unsigned int nUndoPos;
+
+ // (memory only) Total amount of work (expected number of hashes) in the chain up to and including this block
+ uint256 nChainWork;
+
+ // Number of transactions in this block.
+ // Note: in a potential headers-first mode, this number cannot be relied upon
+ unsigned int nTx;
+
+ // (memory only) Number of transactions in the chain up to and including this block
+ unsigned int nChainTx; // change to 64-bit type when necessary; won't happen before 2030
+
+ // Verification status of this block. See enum BlockStatus
+ unsigned int nStatus;
+
+ // block header
+ int nVersion;
+ uint256 hashMerkleRoot;
+ unsigned int nTime;
+ unsigned int nBits;
+ unsigned int nNonce;
+
+ // (memory only) Sequencial id assigned to distinguish order in which blocks are received.
+ uint32_t nSequenceId;
+
+ void SetNull()
+ {
+ phashBlock = NULL;
+ pprev = NULL;
+ pskip = NULL;
+ nHeight = 0;
+ nFile = 0;
+ nDataPos = 0;
+ nUndoPos = 0;
+ nChainWork = 0;
+ nTx = 0;
+ nChainTx = 0;
+ nStatus = 0;
+ nSequenceId = 0;
+
+ nVersion = 0;
+ hashMerkleRoot = 0;
+ nTime = 0;
+ nBits = 0;
+ nNonce = 0;
+ }
+
+ CBlockIndex()
+ {
+ SetNull();
+ }
+
+ CBlockIndex(CBlockHeader& block)
+ {
+ SetNull();
+
+ nVersion = block.nVersion;
+ hashMerkleRoot = block.hashMerkleRoot;
+ nTime = block.nTime;
+ nBits = block.nBits;
+ nNonce = block.nNonce;
+ }
+
+ CDiskBlockPos GetBlockPos() const {
+ CDiskBlockPos ret;
+ if (nStatus & BLOCK_HAVE_DATA) {
+ ret.nFile = nFile;
+ ret.nPos = nDataPos;
+ }
+ return ret;
+ }
+
+ CDiskBlockPos GetUndoPos() const {
+ CDiskBlockPos ret;
+ if (nStatus & BLOCK_HAVE_UNDO) {
+ ret.nFile = nFile;
+ ret.nPos = nUndoPos;
+ }
+ return ret;
+ }
+
+ CBlockHeader GetBlockHeader() const
+ {
+ CBlockHeader block;
+ block.nVersion = nVersion;
+ if (pprev)
+ block.hashPrevBlock = pprev->GetBlockHash();
+ block.hashMerkleRoot = hashMerkleRoot;
+ block.nTime = nTime;
+ block.nBits = nBits;
+ block.nNonce = nNonce;
+ return block;
+ }
+
+ uint256 GetBlockHash() const
+ {
+ return *phashBlock;
+ }
+
+ int64_t GetBlockTime() const
+ {
+ return (int64_t)nTime;
+ }
+
+ uint256 GetBlockWork() const
+ {
+ return GetProofIncrement(nBits);
+ }
+
+ enum { nMedianTimeSpan=11 };
+
+ int64_t GetMedianTimePast() const
+ {
+ int64_t pmedian[nMedianTimeSpan];
+ int64_t* pbegin = &pmedian[nMedianTimeSpan];
+ int64_t* pend = &pmedian[nMedianTimeSpan];
+
+ const CBlockIndex* pindex = this;
+ for (int i = 0; i < nMedianTimeSpan && pindex; i++, pindex = pindex->pprev)
+ *(--pbegin) = pindex->GetBlockTime();
+
+ std::sort(pbegin, pend);
+ return pbegin[(pend - pbegin)/2];
+ }
+
+ /**
+ * Returns true if there are nRequired or more blocks of minVersion or above
+ * in the last Params().ToCheckBlockUpgradeMajority() blocks, starting at pstart
+ * and going backwards.
+ */
+ static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart,
+ unsigned int nRequired);
+
+ std::string ToString() const
+ {
+ return strprintf("CBlockIndex(pprev=%p, nHeight=%d, merkle=%s, hashBlock=%s)",
+ pprev, nHeight,
+ hashMerkleRoot.ToString(),
+ GetBlockHash().ToString());
+ }
+
+ // Check whether this block index entry is valid up to the passed validity level.
+ bool IsValid(enum BlockStatus nUpTo = BLOCK_VALID_TRANSACTIONS) const
+ {
+ assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
+ if (nStatus & BLOCK_FAILED_MASK)
+ return false;
+ return ((nStatus & BLOCK_VALID_MASK) >= nUpTo);
+ }
+
+ // Raise the validity level of this block index entry.
+ // Returns true if the validity was changed.
+ bool RaiseValidity(enum BlockStatus nUpTo)
+ {
+ assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
+ if (nStatus & BLOCK_FAILED_MASK)
+ return false;
+ if ((nStatus & BLOCK_VALID_MASK) < nUpTo) {
+ nStatus = (nStatus & ~BLOCK_VALID_MASK) | nUpTo;
+ return true;
+ }
+ return false;
+ }
+
+ // Build the skiplist pointer for this entry.
+ void BuildSkip();
+
+ // Efficiently find an ancestor of this block.
+ CBlockIndex* GetAncestor(int height);
+ const CBlockIndex* GetAncestor(int height) const;
+};
+
+/** Used to marshal pointers into hashes for db storage. */
+class CDiskBlockIndex : public CBlockIndex
+{
+public:
+ uint256 hashPrev;
+
+ CDiskBlockIndex() {
+ hashPrev = 0;
+ }
+
+ explicit CDiskBlockIndex(CBlockIndex* pindex) : CBlockIndex(*pindex) {
+ hashPrev = (pprev ? pprev->GetBlockHash() : 0);
+ }
+
+ ADD_SERIALIZE_METHODS;
+
+ template <typename Stream, typename Operation>
+ inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+ if (!(nType & SER_GETHASH))
+ READWRITE(VARINT(nVersion));
+
+ READWRITE(VARINT(nHeight));
+ READWRITE(VARINT(nStatus));
+ READWRITE(VARINT(nTx));
+ if (nStatus & (BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO))
+ READWRITE(VARINT(nFile));
+ if (nStatus & BLOCK_HAVE_DATA)
+ READWRITE(VARINT(nDataPos));
+ if (nStatus & BLOCK_HAVE_UNDO)
+ READWRITE(VARINT(nUndoPos));
+
+ // block header
+ READWRITE(this->nVersion);
+ READWRITE(hashPrev);
+ READWRITE(hashMerkleRoot);
+ READWRITE(nTime);
+ READWRITE(nBits);
+ READWRITE(nNonce);
+ }
+
+ uint256 GetBlockHash() const
+ {
+ CBlockHeader block;
+ block.nVersion = nVersion;
+ block.hashPrevBlock = hashPrev;
+ block.hashMerkleRoot = hashMerkleRoot;
+ block.nTime = nTime;
+ block.nBits = nBits;
+ block.nNonce = nNonce;
+ return block.GetHash();
+ }
+
+
+ std::string ToString() const
+ {
+ std::string str = "CDiskBlockIndex(";
+ str += CBlockIndex::ToString();
+ str += strprintf("\n hashBlock=%s, hashPrev=%s)",
+ GetBlockHash().ToString(),
+ hashPrev.ToString());
+ return str;
+ }
+};
+
+/** An in-memory indexed chain of blocks. */
+class CChain {
+private:
+ std::vector<CBlockIndex*> vChain;
+
+public:
+ /** Returns the index entry for the genesis block of this chain, or NULL if none. */
+ CBlockIndex *Genesis() const {
+ return vChain.size() > 0 ? vChain[0] : NULL;
+ }
+
+ /** Returns the index entry for the tip of this chain, or NULL if none. */
+ CBlockIndex *Tip() const {
+ return vChain.size() > 0 ? vChain[vChain.size() - 1] : NULL;
+ }
+
+ /** Returns the index entry at a particular height in this chain, or NULL if no such height exists. */
+ CBlockIndex *operator[](int nHeight) const {
+ if (nHeight < 0 || nHeight >= (int)vChain.size())
+ return NULL;
+ return vChain[nHeight];
+ }
+
+ /** Compare two chains efficiently. */
+ friend bool operator==(const CChain &a, const CChain &b) {
+ return a.vChain.size() == b.vChain.size() &&
+ a.vChain[a.vChain.size() - 1] == b.vChain[b.vChain.size() - 1];
+ }
+
+ /** Efficiently check whether a block is present in this chain. */
+ bool Contains(const CBlockIndex *pindex) const {
+ return (*this)[pindex->nHeight] == pindex;
+ }
+
+ /** Find the successor of a block in this chain, or NULL if the given index is not found or is the tip. */
+ CBlockIndex *Next(const CBlockIndex *pindex) const {
+ if (Contains(pindex))
+ return (*this)[pindex->nHeight + 1];
+ else
+ return NULL;
+ }
+
+ /** Return the maximal height in the chain. Is equal to chain.Tip() ? chain.Tip()->nHeight : -1. */
+ int Height() const {
+ return vChain.size() - 1;
+ }
+
+ /** Set/initialize a chain with a given tip. Returns the forking point. */
+ CBlockIndex *SetTip(CBlockIndex *pindex);
+
+ /** Return a CBlockLocator that refers to a block in this chain (by default the tip). */
+ CBlockLocator GetLocator(const CBlockIndex *pindex = NULL) const;
+
+ /** Find the last common block between this chain and a block index entry. */
+ const CBlockIndex *FindFork(const CBlockIndex *pindex) const;
+};
+
+#endif // H_BITCOIN_CHAIN