/**
* Novacoin classes library
* Copyright (C) 2015 Alex D. (balthazar.ad@gmail.com)
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*/
using System;
using System.Text;
using System.Collections.Generic;
using System.IO;
using System.Diagnostics.Contracts;
using System.Numerics;
namespace Novacoin
{
[Serializable]
public class TransactionConstructorException : Exception
{
public TransactionConstructorException()
{
}
public TransactionConstructorException(string message)
: base(message)
{
}
public TransactionConstructorException(string message, Exception inner)
: base(message, inner)
{
}
}
///
/// Represents the transaction.
///
public class CTransaction
{
///
/// One cent = 10000 satoshis.
///
public const long nCent = 10000;
///
/// One coin = 1000000 satoshis.
///
public const long nCoin = 1000000;
///
/// Sanity checking threshold.
///
public const long nMaxMoney = 2000000000 * nCoin;
public const long nMinTxFee = nCent / 10;
public const long nMinRelayTxFee = nCent / 50;
public const long nMinTxoutAmount = nCent / 100;
///
/// Maximum transaction size is 250Kb
///
public const uint nMaxTxSize = 250000;
public enum MinFeeMode
{
GMF_BLOCK,
GMF_RELAY,
GMF_SEND,
}
///
/// Version of transaction schema.
///
public uint nVersion;
///
/// Transaction timestamp.
///
public uint nTime;
///
/// Array of transaction inputs
///
public CTxIn[] vin;
///
/// Array of transaction outputs
///
public CTxOut[] vout;
///
/// Block height or timestamp when transaction is final
///
public uint nLockTime;
///
/// Initialize an empty instance
///
public CTransaction()
{
// Initialize empty input and output arrays. Please note that such
// configuration is not valid for real transaction, you have to supply
// at least one input and one output.
nVersion = 1;
nTime = 0;
vin = new CTxIn[0];
vout = new CTxOut[0];
nLockTime = 0;
}
///
/// Initialize new instance as a copy of another transaction
///
/// Transaction to copy from
public CTransaction(CTransaction tx)
{
nVersion = tx.nVersion;
nTime = tx.nTime;
vin = new CTxIn[tx.vin.Length];
for (int i = 0; i < vin.Length; i++)
{
vin[i] = new CTxIn(tx.vin[i]);
}
vout = new CTxOut[tx.vout.Length];
for (int i = 0; i < vout.Length; i++)
{
vout[i] = new CTxOut(tx.vout[i]);
}
nLockTime = tx.nLockTime;
}
///
/// Attempts to execute all transaction scripts and validate the results.
///
/// Checking result.
public bool VerifyScripts()
{
if (IsCoinBase)
{
return true;
}
for (int i = 0; i < vin.Length; i++)
{
var outpoint = vin[i].prevout;
TxOutItem txOutCursor;
if (!CBlockStore.Instance.GetTxOutCursor(outpoint, out txOutCursor))
return false;
if (!ScriptCode.VerifyScript(vin[i].scriptSig, txOutCursor.scriptPubKey, this, i, (int)scriptflag.SCRIPT_VERIFY_P2SH, 0))
return false;
}
return true;
}
///
/// Calculate amount of signature operations without trying to properly evaluate P2SH scripts.
///
public uint LegacySigOpCount
{
get
{
uint nSigOps = 0;
if (!IsCoinBase)
{
// http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2012-July/001718.html
foreach (var txin in vin)
{
nSigOps += txin.scriptSig.GetSigOpCount(false);
}
}
foreach (var txout in vout)
{
nSigOps += txout.scriptPubKey.GetSigOpCount(false);
}
return nSigOps;
}
}
///
/// Basic sanity checkings
///
/// Checking result
public bool CheckTransaction()
{
if (Size > nMaxTxSize || vin.Length == 0 || vout.Length == 0)
{
return false;
}
// Check for empty or overflow output values
long nValueOut = 0;
for (int i = 0; i < vout.Length; i++)
{
CTxOut txout = vout[i];
if (txout.IsEmpty && !IsCoinBase && !IsCoinStake)
{
// Empty outputs aren't allowed for user transactions.
return false;
}
nValueOut += txout.nValue;
if (!MoneyRange(nValueOut))
{
return false;
}
}
// Check for duplicate inputs
var InOutPoints = new List();
foreach (var txin in vin)
{
if (InOutPoints.IndexOf(txin.prevout) != -1)
{
// Duplicate input.
return false;
}
InOutPoints.Add(txin.prevout);
}
if (IsCoinBase)
{
if (vin[0].scriptSig.Size < 2 || vin[0].scriptSig.Size > 100)
{
// Script size is invalid
return false;
}
}
else
{
foreach (var txin in vin)
{
if (txin.prevout.IsNull)
{
// Null input in non-coinbase transaction.
return false;
}
}
}
return true;
}
public bool IsFinal(uint nBlockHeight = 0, uint nBlockTime = 0)
{
// Time based nLockTime
if (nLockTime == 0)
{
return true;
}
if (nBlockHeight == 0)
{
nBlockHeight = uint.MaxValue; // TODO: stupid stub here, should be best height instead.
}
if (nBlockTime == 0)
{
nBlockTime = NetInfo.GetAdjustedTime();
}
if (nLockTime < (nLockTime < NetInfo.nLockTimeThreshold ? nBlockHeight : nBlockTime))
{
return true;
}
foreach (var txin in vin)
{
if (!txin.IsFinal)
{
return false;
}
}
return true;
}
///
/// Parse byte sequence and initialize new instance of CTransaction
///
/// Byte sequence
public CTransaction(byte[] txBytes)
{
try
{
var stream = new MemoryStream(txBytes);
var reader = new BinaryReader(stream);
nVersion = reader.ReadUInt32();
nTime = reader.ReadUInt32();
int nInputs = (int)VarInt.ReadVarInt(ref reader);
vin = new CTxIn[nInputs];
for (int nCurrentInput = 0; nCurrentInput < nInputs; nCurrentInput++)
{
// Fill inputs array
vin[nCurrentInput] = new CTxIn();
vin[nCurrentInput].prevout = new COutPoint(reader.ReadBytes(36));
int nScriptSigLen = (int)VarInt.ReadVarInt(ref reader);
vin[nCurrentInput].scriptSig = new CScript(reader.ReadBytes(nScriptSigLen));
vin[nCurrentInput].nSequence = reader.ReadUInt32();
}
int nOutputs = (int)VarInt.ReadVarInt(ref reader);
vout = new CTxOut[nOutputs];
for (int nCurrentOutput = 0; nCurrentOutput < nOutputs; nCurrentOutput++)
{
// Fill outputs array
vout[nCurrentOutput] = new CTxOut();
vout[nCurrentOutput].nValue = reader.ReadInt64();
int nScriptPKLen = (int)VarInt.ReadVarInt(ref reader);
vout[nCurrentOutput].scriptPubKey = new CScript(reader.ReadBytes(nScriptPKLen));
}
nLockTime = reader.ReadUInt32();
}
catch (Exception e)
{
throw new TransactionConstructorException("Deserialization failed", e);
}
}
///
/// Serialized size
///
public uint Size
{
get
{
uint nSize = 12; // nVersion, nTime, nLockLime
nSize += VarInt.GetEncodedSize(vin.Length);
nSize += VarInt.GetEncodedSize(vout.Length);
foreach (var input in vin)
{
nSize += input.Size;
}
foreach (var output in vout)
{
nSize += output.Size;
}
return nSize;
}
}
///
/// Read transactions array which is encoded in the block body.
///
/// Bytes sequence
/// Transactions array
internal static CTransaction[] ReadTransactionsList(ref BinaryReader reader)
{
try
{
// Read amount of transactions
int nTransactions = (int)VarInt.ReadVarInt(ref reader);
var tx = new CTransaction[nTransactions];
for (int nTx = 0; nTx < nTransactions; nTx++)
{
// Fill the transactions array
tx[nTx] = new CTransaction();
tx[nTx].nVersion = reader.ReadUInt32();
tx[nTx].nTime = reader.ReadUInt32();
// Inputs array
tx[nTx].vin = CTxIn.ReadTxInList(ref reader);
// outputs array
tx[nTx].vout = CTxOut.ReadTxOutList(ref reader);
tx[nTx].nLockTime = reader.ReadUInt32();
}
return tx;
}
catch (Exception e)
{
throw new TransactionConstructorException("Deserialization failed", e);
}
}
public bool IsCoinBase
{
get { return (vin.Length == 1 && vin[0].prevout.IsNull && vout.Length >= 1); }
}
public bool IsCoinStake
{
get
{
return (vin.Length > 0 && (!vin[0].prevout.IsNull) && vout.Length >= 2 && vout[0].IsEmpty);
}
}
///
/// Transaction hash
///
public uint256 Hash
{
get { return CryptoUtils.ComputeHash256(this); }
}
///
/// Amount of novacoins spent by this transaction.
///
public long nValueOut
{
get
{
long nValueOut = 0;
foreach (var txout in vout)
{
nValueOut += txout.nValue;
Contract.Assert(MoneyRange(txout.nValue) && MoneyRange(nValueOut));
}
return nValueOut;
}
}
///
/// A sequence of bytes, which corresponds to the current state of CTransaction.
///
public static implicit operator byte[] (CTransaction tx)
{
var stream = new MemoryStream();
var writer = new BinaryWriter(stream);
writer.Write(tx.nVersion);
writer.Write(tx.nTime);
writer.Write(VarInt.EncodeVarInt(tx.vin.LongLength));
foreach (var input in tx.vin)
{
writer.Write(input);
}
writer.Write(VarInt.EncodeVarInt(tx.vout.LongLength));
foreach (var output in tx.vout)
{
writer.Write(output);
}
writer.Write(tx.nLockTime);
var resultBytes = stream.ToArray();
writer.Close();
return resultBytes;
}
public override string ToString()
{
var sb = new StringBuilder();
sb.AppendFormat("CTransaction(\n nVersion={0},\n nTime={1},\n", nVersion, nTime);
foreach (var txin in vin)
{
sb.AppendFormat(" {0},\n", txin);
}
foreach (var txout in vout)
{
sb.AppendFormat(" {0},\n", txout);
}
sb.AppendFormat("\nnLockTime={0}\n)", nLockTime);
return sb.ToString();
}
public static bool MoneyRange(long nValue) { return (nValue <= nMaxMoney); }
///
/// Get total sigops.
///
/// Inputs map.
/// Amount of sigops.
public uint GetP2SHSigOpCount(ref Dictionary inputs)
{
if (IsCoinBase)
{
return 0;
}
uint nSigOps = 0;
for (var i = 0; i < vin.Length; i++)
{
var prevout = GetOutputFor(vin[i], ref inputs);
if (prevout.scriptPubKey.IsPayToScriptHash)
{
nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
}
}
return nSigOps;
}
///
/// Get sum of inputs spent by this transaction.
///
/// Reference to innputs map.
/// Sum of inputs.
public long GetValueIn(ref Dictionary inputs)
{
if (IsCoinBase)
{
return 0;
}
long nResult = 0;
for (int i = 0; i < vin.Length; i++)
{
nResult += GetOutputFor(vin[i], ref inputs).nValue;
}
return nResult;
}
///
/// Helper method to find output in the map.
///
/// Transaction input.
/// eference to inuts map.
/// Parent output.
private CTxOut GetOutputFor(CTxIn input, ref Dictionary inputs)
{
if (!inputs.ContainsKey(input.prevout))
{
throw new Exception("No such input");
}
var outItem = inputs[input.prevout];
return new CTxOut(outItem.nValue, outItem.scriptPubKey);
}
///
/// Calculate coin*age.
///
/// Note, only those coins meeting minimum age requirement counts.
///
/// Inputs set.
/// Coin age calculation result.
/// Result
public bool GetCoinAge(ref Dictionary inputs, out long nCoinAge)
{
BigInteger bnCentSecond = 0; // coin age in the unit of cent-seconds
nCoinAge = 0;
if (IsCoinBase)
{
// Nothing spent by coinbase, coinage is always zero.
return true;
}
for( var i = 0; i nTime)
{
continue; // only count coins meeting min age requirement
}
long nValueIn = input.nValue;
bnCentSecond += new BigInteger(nValueIn) * (nTime - merkleItem.nTime) / nCent;
}
BigInteger bnCoinDay = bnCentSecond * nCent / nCoin / (24 * 60 * 60);
nCoinAge = (long)bnCoinDay;
return true;
}
public long GetMinFee(uint nBlockSize, bool fAllowFree, MinFeeMode mode)
{
long nMinTxFee = CTransaction.nMinTxFee, nMinRelayTxFee = CTransaction.nMinRelayTxFee;
uint nBytes = Size;
if (IsCoinStake)
{
// Enforce 0.01 as minimum fee for old approach or coinstake
nMinTxFee = nCent;
nMinRelayTxFee = nCent;
if (nTime < NetInfo.nStakeValidationSwitchTime)
{
// Enforce zero size for compatibility with old blocks.
nBytes = 0;
}
}
// Base fee is either nMinTxFee or nMinRelayTxFee
long nBaseFee = (mode == MinFeeMode.GMF_RELAY) ? nMinRelayTxFee : nMinTxFee;
uint nNewBlockSize = nBlockSize + nBytes;
long nMinFee = (1 + (long)nBytes / 1000) * nBaseFee;
if (fAllowFree)
{
if (nBlockSize == 1)
{
// Transactions under 1K are free
if (nBytes < 1000)
nMinFee = 0;
}
else
{
// Free transaction area
if (nNewBlockSize < 27000)
nMinFee = 0;
}
}
// To limit dust spam, require additional MIN_TX_FEE/MIN_RELAY_TX_FEE for
// each non empty output which is less than 0.01
//
// It's safe to ignore empty outputs here, because these inputs are allowed
// only for coinbase and coinstake transactions.
foreach (var txout in vout)
{
if (txout.nValue < nCent && !txout.IsEmpty)
{
nMinFee += nBaseFee;
}
}
var nMaxBlockSizeGen = CBlock.nMaxBlockSize / 2;
// Raise the price as the block approaches full
if (nBlockSize != 1 && nNewBlockSize >= nMaxBlockSizeGen / 2)
{
if (nNewBlockSize >= nMaxBlockSizeGen)
{
return nMaxMoney;
}
nMinFee *= nMaxBlockSizeGen / (nMaxBlockSizeGen - nNewBlockSize);
}
if (!MoneyRange(nMinFee))
{
nMinFee = nMaxMoney;
}
return nMinFee;
}
}
}