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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.
#include "script/standard.h"
#include "script/script.h"
#include "util.h"
#include <boost/foreach.hpp>
using namespace std;
typedef vector<unsigned char> valtype;
CScriptID::CScriptID(const CScript& in) : uint160(in.size() ? Hash160(in.begin(), in.end()) : 0) {}
const char* GetTxnOutputType(txnouttype t)
{
switch (t)
{
case TX_NONSTANDARD: return "nonstandard";
case TX_PUBKEY: return "pubkey";
case TX_PUBKEYHASH: return "pubkeyhash";
case TX_SCRIPTHASH: return "scripthash";
case TX_MULTISIG: return "multisig";
case TX_NULL_DATA: return "nulldata";
}
return NULL;
}
//
// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
//
bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsigned char> >& vSolutionsRet)
{
// Templates
static multimap<txnouttype, CScript> mTemplates;
if (mTemplates.empty())
{
// Standard tx, sender provides pubkey, receiver adds signature
mTemplates.insert(make_pair(TX_PUBKEY, CScript() << OP_PUBKEY << OP_CHECKSIG));
// Bitcoin address tx, sender provides hash of pubkey, receiver provides signature and pubkey
mTemplates.insert(make_pair(TX_PUBKEYHASH, CScript() << OP_DUP << OP_HASH160 << OP_PUBKEYHASH << OP_EQUALVERIFY << OP_CHECKSIG));
// Sender provides N pubkeys, receivers provides M signatures
mTemplates.insert(make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));
// Empty, provably prunable, data-carrying output
if (GetBoolArg("-datacarrier", true))
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN << OP_SMALLDATA));
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN));
}
// Shortcut for pay-to-script-hash, which are more constrained than the other types:
// it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
if (scriptPubKey.IsPayToScriptHash())
{
typeRet = TX_SCRIPTHASH;
vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
vSolutionsRet.push_back(hashBytes);
return true;
}
// Scan templates
const CScript& script1 = scriptPubKey;
BOOST_FOREACH(const PAIRTYPE(txnouttype, CScript)& tplate, mTemplates)
{
const CScript& script2 = tplate.second;
vSolutionsRet.clear();
opcodetype opcode1, opcode2;
vector<unsigned char> vch1, vch2;
// Compare
CScript::const_iterator pc1 = script1.begin();
CScript::const_iterator pc2 = script2.begin();
while (true)
{
if (pc1 == script1.end() && pc2 == script2.end())
{
// Found a match
typeRet = tplate.first;
if (typeRet == TX_MULTISIG)
{
// Additional checks for TX_MULTISIG:
unsigned char m = vSolutionsRet.front()[0];
unsigned char n = vSolutionsRet.back()[0];
if (m < 1 || n < 1 || m > n || vSolutionsRet.size()-2 != n)
return false;
}
return true;
}
if (!script1.GetOp(pc1, opcode1, vch1))
break;
if (!script2.GetOp(pc2, opcode2, vch2))
break;
// Template matching opcodes:
if (opcode2 == OP_PUBKEYS)
{
while (vch1.size() >= 33 && vch1.size() <= 65)
{
vSolutionsRet.push_back(vch1);
if (!script1.GetOp(pc1, opcode1, vch1))
break;
}
if (!script2.GetOp(pc2, opcode2, vch2))
break;
// Normal situation is to fall through
// to other if/else statements
}
if (opcode2 == OP_PUBKEY)
{
if (vch1.size() < 33 || vch1.size() > 65)
break;
vSolutionsRet.push_back(vch1);
}
else if (opcode2 == OP_PUBKEYHASH)
{
if (vch1.size() != sizeof(uint160))
break;
vSolutionsRet.push_back(vch1);
}
else if (opcode2 == OP_SMALLINTEGER)
{ // Single-byte small integer pushed onto vSolutions
if (opcode1 == OP_0 ||
(opcode1 >= OP_1 && opcode1 <= OP_16))
{
char n = (char)CScript::DecodeOP_N(opcode1);
vSolutionsRet.push_back(valtype(1, n));
}
else
break;
}
else if (opcode2 == OP_SMALLDATA)
{
// small pushdata, <= MAX_OP_RETURN_RELAY bytes
if (vch1.size() > MAX_OP_RETURN_RELAY)
break;
}
else if (opcode1 != opcode2 || vch1 != vch2)
{
// Others must match exactly
break;
}
}
}
vSolutionsRet.clear();
typeRet = TX_NONSTANDARD;
return false;
}
int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned char> >& vSolutions)
{
switch (t)
{
case TX_NONSTANDARD:
case TX_NULL_DATA:
return -1;
case TX_PUBKEY:
return 1;
case TX_PUBKEYHASH:
return 2;
case TX_MULTISIG:
if (vSolutions.size() < 1 || vSolutions[0].size() < 1)
return -1;
return vSolutions[0][0] + 1;
case TX_SCRIPTHASH:
return 1; // doesn't include args needed by the script
}
return -1;
}
bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
{
vector<valtype> vSolutions;
if (!Solver(scriptPubKey, whichType, vSolutions))
return false;
if (whichType == TX_MULTISIG)
{
unsigned char m = vSolutions.front()[0];
unsigned char n = vSolutions.back()[0];
// Support up to x-of-3 multisig txns as standard
if (n < 1 || n > 3)
return false;
if (m < 1 || m > n)
return false;
}
return whichType != TX_NONSTANDARD;
}
bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet)
{
vector<valtype> vSolutions;
txnouttype whichType;
if (!Solver(scriptPubKey, whichType, vSolutions))
return false;
if (whichType == TX_PUBKEY)
{
CPubKey pubKey(vSolutions[0]);
if (!pubKey.IsValid())
return false;
addressRet = pubKey.GetID();
return true;
}
else if (whichType == TX_PUBKEYHASH)
{
addressRet = CKeyID(uint160(vSolutions[0]));
return true;
}
else if (whichType == TX_SCRIPTHASH)
{
addressRet = CScriptID(uint160(vSolutions[0]));
return true;
}
// Multisig txns have more than one address...
return false;
}
bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, vector<CTxDestination>& addressRet, int& nRequiredRet)
{
addressRet.clear();
typeRet = TX_NONSTANDARD;
vector<valtype> vSolutions;
if (!Solver(scriptPubKey, typeRet, vSolutions))
return false;
if (typeRet == TX_NULL_DATA){
// This is data, not addresses
return false;
}
if (typeRet == TX_MULTISIG)
{
nRequiredRet = vSolutions.front()[0];
for (unsigned int i = 1; i < vSolutions.size()-1; i++)
{
CPubKey pubKey(vSolutions[i]);
if (!pubKey.IsValid())
continue;
CTxDestination address = pubKey.GetID();
addressRet.push_back(address);
}
if (addressRet.empty())
return false;
}
else
{
nRequiredRet = 1;
CTxDestination address;
if (!ExtractDestination(scriptPubKey, address))
return false;
addressRet.push_back(address);
}
return true;
}
namespace
{
class CScriptVisitor : public boost::static_visitor<bool>
{
private:
CScript *script;
public:
CScriptVisitor(CScript *scriptin) { script = scriptin; }
bool operator()(const CNoDestination &dest) const {
script->clear();
return false;
}
bool operator()(const CKeyID &keyID) const {
script->clear();
*script << OP_DUP << OP_HASH160 << ToByteVector(keyID) << OP_EQUALVERIFY << OP_CHECKSIG;
return true;
}
bool operator()(const CScriptID &scriptID) const {
script->clear();
*script << OP_HASH160 << ToByteVector(scriptID) << OP_EQUAL;
return true;
}
};
}
CScript GetScriptForDestination(const CTxDestination& dest)
{
CScript script;
boost::apply_visitor(CScriptVisitor(&script), dest);
return script;
}
CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys)
{
CScript script;
script << CScript::EncodeOP_N(nRequired);
BOOST_FOREACH(const CPubKey& key, keys)
script << ToByteVector(key);
script << CScript::EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
return script;
}