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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 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_CHAIN_H
#define BITCOIN_CHAIN_H
#include "arith_uint256.h"
#include "primitives/block.h"
#include "pow.h"
#include "tinyformat.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); }
std::string ToString() const
{
return strprintf("CBlockDiskPos(nFile=%i, nPos=%i)", nFile, nPos);
}
};
enum BlockStatus {
//! Unused.
BLOCK_VALID_UNKNOWN = 0,
//! Parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future
BLOCK_VALID_HEADER = 1,
//! All parent headers found, difficulty matches, timestamp >= median previous, checkpoint. Implies all parents
//! are also at least TREE.
BLOCK_VALID_TREE = 2,
/**
* Only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids,
* sigops, size, merkle root. Implies all parents are at least TREE but not necessarily TRANSACTIONS. When all
* parent blocks also have TRANSACTIONS, CBlockIndex::nChainTx will be set.
*/
BLOCK_VALID_TRANSACTIONS = 3,
//! Outputs do not overspend inputs, no double spends, coinbase output ok, no immature coinbase spends, BIP30.
//! Implies all parents are also at least CHAIN.
BLOCK_VALID_CHAIN = 4,
//! Scripts & signatures ok. Implies all parents are also at least SCRIPTS.
BLOCK_VALID_SCRIPTS = 5,
//! All validity bits.
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
arith_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.
//! This value will be non-zero only if and only if transactions for this block and all its parents are available.
//! Change to 64-bit type when necessary; won't happen before 2030
unsigned int nChainTx;
//! 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) Sequential 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 = arith_uint256();
nTx = 0;
nChainTx = 0;
nStatus = 0;
nSequenceId = 0;
nVersion = 0;
hashMerkleRoot = uint256();
nTime = 0;
nBits = 0;
nNonce = 0;
}
CBlockIndex()
{
SetNull();
}
CBlockIndex(const 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;
}
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];
}
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 = uint256();
}
explicit CDiskBlockIndex(const CBlockIndex* pindex) : CBlockIndex(*pindex) {
hashPrev = (pprev ? pprev->GetBlockHash() : uint256());
}
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. */
void 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 // BITCOIN_CHAIN_H

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