Move CScript class and dependencies to script/script

2 files changed, 940 insertions, 0 deletions

diff --git a/src/script/script.cpp b/src/script/script.cpp
new file mode 100644
index 0000000000..60d1beac95
--- /dev/null
+++ b/src/script/script.cpp
@@ -0,0 +1,295 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "script.h"
+
+#include <boost/foreach.hpp>
+
+using namespace std;
+
+const char* GetOpName(opcodetype opcode)
+{
+    switch (opcode)
+    {
+    // push value
+    case OP_0                      : return "0";
+    case OP_PUSHDATA1              : return "OP_PUSHDATA1";
+    case OP_PUSHDATA2              : return "OP_PUSHDATA2";
+    case OP_PUSHDATA4              : return "OP_PUSHDATA4";
+    case OP_1NEGATE                : return "-1";
+    case OP_RESERVED               : return "OP_RESERVED";
+    case OP_1                      : return "1";
+    case OP_2                      : return "2";
+    case OP_3                      : return "3";
+    case OP_4                      : return "4";
+    case OP_5                      : return "5";
+    case OP_6                      : return "6";
+    case OP_7                      : return "7";
+    case OP_8                      : return "8";
+    case OP_9                      : return "9";
+    case OP_10                     : return "10";
+    case OP_11                     : return "11";
+    case OP_12                     : return "12";
+    case OP_13                     : return "13";
+    case OP_14                     : return "14";
+    case OP_15                     : return "15";
+    case OP_16                     : return "16";
+
+    // control
+    case OP_NOP                    : return "OP_NOP";
+    case OP_VER                    : return "OP_VER";
+    case OP_IF                     : return "OP_IF";
+    case OP_NOTIF                  : return "OP_NOTIF";
+    case OP_VERIF                  : return "OP_VERIF";
+    case OP_VERNOTIF               : return "OP_VERNOTIF";
+    case OP_ELSE                   : return "OP_ELSE";
+    case OP_ENDIF                  : return "OP_ENDIF";
+    case OP_VERIFY                 : return "OP_VERIFY";
+    case OP_RETURN                 : return "OP_RETURN";
+
+    // stack ops
+    case OP_TOALTSTACK             : return "OP_TOALTSTACK";
+    case OP_FROMALTSTACK           : return "OP_FROMALTSTACK";
+    case OP_2DROP                  : return "OP_2DROP";
+    case OP_2DUP                   : return "OP_2DUP";
+    case OP_3DUP                   : return "OP_3DUP";
+    case OP_2OVER                  : return "OP_2OVER";
+    case OP_2ROT                   : return "OP_2ROT";
+    case OP_2SWAP                  : return "OP_2SWAP";
+    case OP_IFDUP                  : return "OP_IFDUP";
+    case OP_DEPTH                  : return "OP_DEPTH";
+    case OP_DROP                   : return "OP_DROP";
+    case OP_DUP                    : return "OP_DUP";
+    case OP_NIP                    : return "OP_NIP";
+    case OP_OVER                   : return "OP_OVER";
+    case OP_PICK                   : return "OP_PICK";
+    case OP_ROLL                   : return "OP_ROLL";
+    case OP_ROT                    : return "OP_ROT";
+    case OP_SWAP                   : return "OP_SWAP";
+    case OP_TUCK                   : return "OP_TUCK";
+
+    // splice ops
+    case OP_CAT                    : return "OP_CAT";
+    case OP_SUBSTR                 : return "OP_SUBSTR";
+    case OP_LEFT                   : return "OP_LEFT";
+    case OP_RIGHT                  : return "OP_RIGHT";
+    case OP_SIZE                   : return "OP_SIZE";
+
+    // bit logic
+    case OP_INVERT                 : return "OP_INVERT";
+    case OP_AND                    : return "OP_AND";
+    case OP_OR                     : return "OP_OR";
+    case OP_XOR                    : return "OP_XOR";
+    case OP_EQUAL                  : return "OP_EQUAL";
+    case OP_EQUALVERIFY            : return "OP_EQUALVERIFY";
+    case OP_RESERVED1              : return "OP_RESERVED1";
+    case OP_RESERVED2              : return "OP_RESERVED2";
+
+    // numeric
+    case OP_1ADD                   : return "OP_1ADD";
+    case OP_1SUB                   : return "OP_1SUB";
+    case OP_2MUL                   : return "OP_2MUL";
+    case OP_2DIV                   : return "OP_2DIV";
+    case OP_NEGATE                 : return "OP_NEGATE";
+    case OP_ABS                    : return "OP_ABS";
+    case OP_NOT                    : return "OP_NOT";
+    case OP_0NOTEQUAL              : return "OP_0NOTEQUAL";
+    case OP_ADD                    : return "OP_ADD";
+    case OP_SUB                    : return "OP_SUB";
+    case OP_MUL                    : return "OP_MUL";
+    case OP_DIV                    : return "OP_DIV";
+    case OP_MOD                    : return "OP_MOD";
+    case OP_LSHIFT                 : return "OP_LSHIFT";
+    case OP_RSHIFT                 : return "OP_RSHIFT";
+    case OP_BOOLAND                : return "OP_BOOLAND";
+    case OP_BOOLOR                 : return "OP_BOOLOR";
+    case OP_NUMEQUAL               : return "OP_NUMEQUAL";
+    case OP_NUMEQUALVERIFY         : return "OP_NUMEQUALVERIFY";
+    case OP_NUMNOTEQUAL            : return "OP_NUMNOTEQUAL";
+    case OP_LESSTHAN               : return "OP_LESSTHAN";
+    case OP_GREATERTHAN            : return "OP_GREATERTHAN";
+    case OP_LESSTHANOREQUAL        : return "OP_LESSTHANOREQUAL";
+    case OP_GREATERTHANOREQUAL     : return "OP_GREATERTHANOREQUAL";
+    case OP_MIN                    : return "OP_MIN";
+    case OP_MAX                    : return "OP_MAX";
+    case OP_WITHIN                 : return "OP_WITHIN";
+
+    // crypto
+    case OP_RIPEMD160              : return "OP_RIPEMD160";
+    case OP_SHA1                   : return "OP_SHA1";
+    case OP_SHA256                 : return "OP_SHA256";
+    case OP_HASH160                : return "OP_HASH160";
+    case OP_HASH256                : return "OP_HASH256";
+    case OP_CODESEPARATOR          : return "OP_CODESEPARATOR";
+    case OP_CHECKSIG               : return "OP_CHECKSIG";
+    case OP_CHECKSIGVERIFY         : return "OP_CHECKSIGVERIFY";
+    case OP_CHECKMULTISIG          : return "OP_CHECKMULTISIG";
+    case OP_CHECKMULTISIGVERIFY    : return "OP_CHECKMULTISIGVERIFY";
+
+    // expanson
+    case OP_NOP1                   : return "OP_NOP1";
+    case OP_NOP2                   : return "OP_NOP2";
+    case OP_NOP3                   : return "OP_NOP3";
+    case OP_NOP4                   : return "OP_NOP4";
+    case OP_NOP5                   : return "OP_NOP5";
+    case OP_NOP6                   : return "OP_NOP6";
+    case OP_NOP7                   : return "OP_NOP7";
+    case OP_NOP8                   : return "OP_NOP8";
+    case OP_NOP9                   : return "OP_NOP9";
+    case OP_NOP10                  : return "OP_NOP10";
+
+    case OP_INVALIDOPCODE          : return "OP_INVALIDOPCODE";
+
+    // Note:
+    //  The template matching params OP_SMALLDATA/etc are defined in opcodetype enum
+    //  as kind of implementation hack, they are *NOT* real opcodes.  If found in real
+    //  Script, just let the default: case deal with them.
+
+    default:
+        return "OP_UNKNOWN";
+    }
+}
+
+unsigned int CScript::GetSigOpCount(bool fAccurate) const
+{
+    unsigned int n = 0;
+    const_iterator pc = begin();
+    opcodetype lastOpcode = OP_INVALIDOPCODE;
+    while (pc < end())
+    {
+        opcodetype opcode;
+        if (!GetOp(pc, opcode))
+            break;
+        if (opcode == OP_CHECKSIG || opcode == OP_CHECKSIGVERIFY)
+            n++;
+        else if (opcode == OP_CHECKMULTISIG || opcode == OP_CHECKMULTISIGVERIFY)
+        {
+            if (fAccurate && lastOpcode >= OP_1 && lastOpcode <= OP_16)
+                n += DecodeOP_N(lastOpcode);
+            else
+                n += 20;
+        }
+        lastOpcode = opcode;
+    }
+    return n;
+}
+
+unsigned int CScript::GetSigOpCount(const CScript& scriptSig) const
+{
+    if (!IsPayToScriptHash())
+        return GetSigOpCount(true);
+
+    // This is a pay-to-script-hash scriptPubKey;
+    // get the last item that the scriptSig
+    // pushes onto the stack:
+    const_iterator pc = scriptSig.begin();
+    vector<unsigned char> data;
+    while (pc < scriptSig.end())
+    {
+        opcodetype opcode;
+        if (!scriptSig.GetOp(pc, opcode, data))
+            return 0;
+        if (opcode > OP_16)
+            return 0;
+    }
+
+    /// ... and return its opcount:
+    CScript subscript(data.begin(), data.end());
+    return subscript.GetSigOpCount(true);
+}
+
+bool CScript::IsPayToScriptHash() const
+{
+    // Extra-fast test for pay-to-script-hash CScripts:
+    return (this->size() == 23 &&
+            this->at(0) == OP_HASH160 &&
+            this->at(1) == 0x14 &&
+            this->at(22) == OP_EQUAL);
+}
+
+bool CScript::IsPushOnly() const
+{
+    const_iterator pc = begin();
+    while (pc < end())
+    {
+        opcodetype opcode;
+        if (!GetOp(pc, opcode))
+            return false;
+        // Note that IsPushOnly() *does* consider OP_RESERVED to be a
+        // push-type opcode, however execution of OP_RESERVED fails, so
+        // it's not relevant to P2SH as the scriptSig would fail prior to
+        // the P2SH special validation code being executed.
+        if (opcode > OP_16)
+            return false;
+    }
+    return true;
+}
+
+bool CScript::HasCanonicalPushes() const
+{
+    const_iterator pc = begin();
+    while (pc < end())
+    {
+        opcodetype opcode;
+        std::vector<unsigned char> data;
+        if (!GetOp(pc, opcode, data))
+            return false;
+        if (opcode > OP_16)
+            continue;
+        if (opcode < OP_PUSHDATA1 && opcode > OP_0 && (data.size() == 1 && data[0] <= 16))
+            // Could have used an OP_n code, rather than a 1-byte push.
+            return false;
+        if (opcode == OP_PUSHDATA1 && data.size() < OP_PUSHDATA1)
+            // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
+            return false;
+        if (opcode == OP_PUSHDATA2 && data.size() <= 0xFF)
+            // Could have used an OP_PUSHDATA1.
+            return false;
+        if (opcode == OP_PUSHDATA4 && data.size() <= 0xFFFF)
+            // Could have used an OP_PUSHDATA2.
+            return false;
+    }
+    return true;
+}
+
+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 << keyID << OP_EQUALVERIFY << OP_CHECKSIG;
+        return true;
+    }
+
+    bool operator()(const CScriptID &scriptID) const {
+        script->clear();
+        *script << OP_HASH160 << scriptID << OP_EQUAL;
+        return true;
+    }
+};
+
+void CScript::SetDestination(const CTxDestination& dest)
+{
+    boost::apply_visitor(CScriptVisitor(this), dest);
+}
+
+void CScript::SetMultisig(int nRequired, const std::vector<CPubKey>& keys)
+{
+    this->clear();
+
+    *this << EncodeOP_N(nRequired);
+    BOOST_FOREACH(const CPubKey& key, keys)
+        *this << key;
+    *this << EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
+}
diff --git a/src/script/script.h b/src/script/script.h
new file mode 100644
index 0000000000..21847c09bd
--- /dev/null
+++ b/src/script/script.h
@@ -0,0 +1,645 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef H_BITCOIN_SCRIPT
+#define H_BITCOIN_SCRIPT
+
+#include "key.h"
+#include "tinyformat.h"
+#include "utilstrencodings.h"
+
+#include <stdexcept>
+
+#include <boost/variant.hpp>
+
+static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520; // bytes
+
+/** Script opcodes */
+enum opcodetype
+{
+    // push value
+    OP_0 = 0x00,
+    OP_FALSE = OP_0,
+    OP_PUSHDATA1 = 0x4c,
+    OP_PUSHDATA2 = 0x4d,
+    OP_PUSHDATA4 = 0x4e,
+    OP_1NEGATE = 0x4f,
+    OP_RESERVED = 0x50,
+    OP_1 = 0x51,
+    OP_TRUE=OP_1,
+    OP_2 = 0x52,
+    OP_3 = 0x53,
+    OP_4 = 0x54,
+    OP_5 = 0x55,
+    OP_6 = 0x56,
+    OP_7 = 0x57,
+    OP_8 = 0x58,
+    OP_9 = 0x59,
+    OP_10 = 0x5a,
+    OP_11 = 0x5b,
+    OP_12 = 0x5c,
+    OP_13 = 0x5d,
+    OP_14 = 0x5e,
+    OP_15 = 0x5f,
+    OP_16 = 0x60,
+
+    // control
+    OP_NOP = 0x61,
+    OP_VER = 0x62,
+    OP_IF = 0x63,
+    OP_NOTIF = 0x64,
+    OP_VERIF = 0x65,
+    OP_VERNOTIF = 0x66,
+    OP_ELSE = 0x67,
+    OP_ENDIF = 0x68,
+    OP_VERIFY = 0x69,
+    OP_RETURN = 0x6a,
+
+    // stack ops
+    OP_TOALTSTACK = 0x6b,
+    OP_FROMALTSTACK = 0x6c,
+    OP_2DROP = 0x6d,
+    OP_2DUP = 0x6e,
+    OP_3DUP = 0x6f,
+    OP_2OVER = 0x70,
+    OP_2ROT = 0x71,
+    OP_2SWAP = 0x72,
+    OP_IFDUP = 0x73,
+    OP_DEPTH = 0x74,
+    OP_DROP = 0x75,
+    OP_DUP = 0x76,
+    OP_NIP = 0x77,
+    OP_OVER = 0x78,
+    OP_PICK = 0x79,
+    OP_ROLL = 0x7a,
+    OP_ROT = 0x7b,
+    OP_SWAP = 0x7c,
+    OP_TUCK = 0x7d,
+
+    // splice ops
+    OP_CAT = 0x7e,
+    OP_SUBSTR = 0x7f,
+    OP_LEFT = 0x80,
+    OP_RIGHT = 0x81,
+    OP_SIZE = 0x82,
+
+    // bit logic
+    OP_INVERT = 0x83,
+    OP_AND = 0x84,
+    OP_OR = 0x85,
+    OP_XOR = 0x86,
+    OP_EQUAL = 0x87,
+    OP_EQUALVERIFY = 0x88,
+    OP_RESERVED1 = 0x89,
+    OP_RESERVED2 = 0x8a,
+
+    // numeric
+    OP_1ADD = 0x8b,
+    OP_1SUB = 0x8c,
+    OP_2MUL = 0x8d,
+    OP_2DIV = 0x8e,
+    OP_NEGATE = 0x8f,
+    OP_ABS = 0x90,
+    OP_NOT = 0x91,
+    OP_0NOTEQUAL = 0x92,
+
+    OP_ADD = 0x93,
+    OP_SUB = 0x94,
+    OP_MUL = 0x95,
+    OP_DIV = 0x96,
+    OP_MOD = 0x97,
+    OP_LSHIFT = 0x98,
+    OP_RSHIFT = 0x99,
+
+    OP_BOOLAND = 0x9a,
+    OP_BOOLOR = 0x9b,
+    OP_NUMEQUAL = 0x9c,
+    OP_NUMEQUALVERIFY = 0x9d,
+    OP_NUMNOTEQUAL = 0x9e,
+    OP_LESSTHAN = 0x9f,
+    OP_GREATERTHAN = 0xa0,
+    OP_LESSTHANOREQUAL = 0xa1,
+    OP_GREATERTHANOREQUAL = 0xa2,
+    OP_MIN = 0xa3,
+    OP_MAX = 0xa4,
+
+    OP_WITHIN = 0xa5,
+
+    // crypto
+    OP_RIPEMD160 = 0xa6,
+    OP_SHA1 = 0xa7,
+    OP_SHA256 = 0xa8,
+    OP_HASH160 = 0xa9,
+    OP_HASH256 = 0xaa,
+    OP_CODESEPARATOR = 0xab,
+    OP_CHECKSIG = 0xac,
+    OP_CHECKSIGVERIFY = 0xad,
+    OP_CHECKMULTISIG = 0xae,
+    OP_CHECKMULTISIGVERIFY = 0xaf,
+
+    // expansion
+    OP_NOP1 = 0xb0,
+    OP_NOP2 = 0xb1,
+    OP_NOP3 = 0xb2,
+    OP_NOP4 = 0xb3,
+    OP_NOP5 = 0xb4,
+    OP_NOP6 = 0xb5,
+    OP_NOP7 = 0xb6,
+    OP_NOP8 = 0xb7,
+    OP_NOP9 = 0xb8,
+    OP_NOP10 = 0xb9,
+
+
+    // template matching params
+    OP_SMALLDATA = 0xf9,
+    OP_SMALLINTEGER = 0xfa,
+    OP_PUBKEYS = 0xfb,
+    OP_PUBKEYHASH = 0xfd,
+    OP_PUBKEY = 0xfe,
+
+    OP_INVALIDOPCODE = 0xff,
+};
+
+const char* GetOpName(opcodetype opcode);
+
+class scriptnum_error : public std::runtime_error
+{
+public:
+    explicit scriptnum_error(const std::string& str) : std::runtime_error(str) {}
+};
+
+class CScriptNum
+{
+// Numeric opcodes (OP_1ADD, etc) are restricted to operating on 4-byte integers.
+// The semantics are subtle, though: operands must be in the range [-2^31 +1...2^31 -1],
+// but results may overflow (and are valid as long as they are not used in a subsequent
+// numeric operation). CScriptNum enforces those semantics by storing results as
+// an int64 and allowing out-of-range values to be returned as a vector of bytes but
+// throwing an exception if arithmetic is done or the result is interpreted as an integer.
+public:
+
+    explicit CScriptNum(const int64_t& n)
+    {
+        m_value = n;
+    }
+
+    explicit CScriptNum(const std::vector<unsigned char>& vch)
+    {
+        if (vch.size() > nMaxNumSize)
+            throw scriptnum_error("CScriptNum(const std::vector<unsigned char>&) : overflow");
+        m_value = set_vch(vch);
+    }
+
+    inline bool operator==(const int64_t& rhs) const    { return m_value == rhs; }
+    inline bool operator!=(const int64_t& rhs) const    { return m_value != rhs; }
+    inline bool operator<=(const int64_t& rhs) const    { return m_value <= rhs; }
+    inline bool operator< (const int64_t& rhs) const    { return m_value <  rhs; }
+    inline bool operator>=(const int64_t& rhs) const    { return m_value >= rhs; }
+    inline bool operator> (const int64_t& rhs) const    { return m_value >  rhs; }
+
+    inline bool operator==(const CScriptNum& rhs) const { return operator==(rhs.m_value); }
+    inline bool operator!=(const CScriptNum& rhs) const { return operator!=(rhs.m_value); }
+    inline bool operator<=(const CScriptNum& rhs) const { return operator<=(rhs.m_value); }
+    inline bool operator< (const CScriptNum& rhs) const { return operator< (rhs.m_value); }
+    inline bool operator>=(const CScriptNum& rhs) const { return operator>=(rhs.m_value); }
+    inline bool operator> (const CScriptNum& rhs) const { return operator> (rhs.m_value); }
+
+    inline CScriptNum operator+(   const int64_t& rhs)    const { return CScriptNum(m_value + rhs);}
+    inline CScriptNum operator-(   const int64_t& rhs)    const { return CScriptNum(m_value - rhs);}
+    inline CScriptNum operator+(   const CScriptNum& rhs) const { return operator+(rhs.m_value);   }
+    inline CScriptNum operator-(   const CScriptNum& rhs) const { return operator-(rhs.m_value);   }
+
+    inline CScriptNum& operator+=( const CScriptNum& rhs)       { return operator+=(rhs.m_value);  }
+    inline CScriptNum& operator-=( const CScriptNum& rhs)       { return operator-=(rhs.m_value);  }
+
+    inline CScriptNum operator-()                         const
+    {
+        assert(m_value != std::numeric_limits<int64_t>::min());
+        return CScriptNum(-m_value);
+    }
+
+    inline CScriptNum& operator=( const int64_t& rhs)
+    {
+        m_value = rhs;
+        return *this;
+    }
+
+    inline CScriptNum& operator+=( const int64_t& rhs)
+    {
+        assert(rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) ||
+                           (rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs));
+        m_value += rhs;
+        return *this;
+    }
+
+    inline CScriptNum& operator-=( const int64_t& rhs)
+    {
+        assert(rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) ||
+                           (rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs));
+        m_value -= rhs;
+        return *this;
+    }
+
+    int getint() const
+    {
+        if (m_value > std::numeric_limits<int>::max())
+            return std::numeric_limits<int>::max();
+        else if (m_value < std::numeric_limits<int>::min())
+            return std::numeric_limits<int>::min();
+        return m_value;
+    }
+
+    std::vector<unsigned char> getvch() const
+    {
+        return serialize(m_value);
+    }
+
+    static std::vector<unsigned char> serialize(const int64_t& value)
+    {
+        if(value == 0)
+            return std::vector<unsigned char>();
+
+        std::vector<unsigned char> result;
+        const bool neg = value < 0;
+        uint64_t absvalue = neg ? -value : value;
+
+        while(absvalue)
+        {
+            result.push_back(absvalue & 0xff);
+            absvalue >>= 8;
+        }
+
+//    - If the most significant byte is >= 0x80 and the value is positive, push a
+//    new zero-byte to make the significant byte < 0x80 again.
+
+//    - If the most significant byte is >= 0x80 and the value is negative, push a
+//    new 0x80 byte that will be popped off when converting to an integral.
+
+//    - If the most significant byte is < 0x80 and the value is negative, add
+//    0x80 to it, since it will be subtracted and interpreted as a negative when
+//    converting to an integral.
+
+        if (result.back() & 0x80)
+            result.push_back(neg ? 0x80 : 0);
+        else if (neg)
+            result.back() |= 0x80;
+
+        return result;
+    }
+
+    static const size_t nMaxNumSize = 4;
+
+private:
+    static int64_t set_vch(const std::vector<unsigned char>& vch)
+    {
+      if (vch.empty())
+          return 0;
+
+      int64_t result = 0;
+      for (size_t i = 0; i != vch.size(); ++i)
+          result |= static_cast<int64_t>(vch[i]) << 8*i;
+
+      // If the input vector's most significant byte is 0x80, remove it from
+      // the result's msb and return a negative.
+      if (vch.back() & 0x80)
+          return -(result & ~(0x80ULL << (8 * (vch.size() - 1))));
+
+      return result;
+    }
+
+    int64_t m_value;
+};
+
+inline std::string ValueString(const std::vector<unsigned char>& vch)
+{
+    if (vch.size() <= 4)
+        return strprintf("%d", CScriptNum(vch).getint());
+    else
+        return HexStr(vch);
+}
+
+class CNoDestination {
+public:
+    friend bool operator==(const CNoDestination &a, const CNoDestination &b) { return true; }
+    friend bool operator<(const CNoDestination &a, const CNoDestination &b) { return true; }
+};
+
+/** A txout script template with a specific destination. It is either:
+ *  * CNoDestination: no destination set
+ *  * CKeyID: TX_PUBKEYHASH destination
+ *  * CScriptID: TX_SCRIPTHASH destination
+ *  A CTxDestination is the internal data type encoded in a CBitcoinAddress
+ */
+typedef boost::variant<CNoDestination, CKeyID, CScriptID> CTxDestination;
+
+/** Serialized script, used inside transaction inputs and outputs */
+class CScript : public std::vector<unsigned char>
+{
+protected:
+    CScript& push_int64(int64_t n)
+    {
+        if (n == -1 || (n >= 1 && n <= 16))
+        {
+            push_back(n + (OP_1 - 1));
+        }
+        else
+        {
+            *this << CScriptNum::serialize(n);
+        }
+        return *this;
+    }
+public:
+    CScript() { }
+    CScript(const CScript& b) : std::vector<unsigned char>(b.begin(), b.end()) { }
+    CScript(const_iterator pbegin, const_iterator pend) : std::vector<unsigned char>(pbegin, pend) { }
+#ifndef _MSC_VER
+    CScript(const unsigned char* pbegin, const unsigned char* pend) : std::vector<unsigned char>(pbegin, pend) { }
+#endif
+
+    CScript& operator+=(const CScript& b)
+    {
+        insert(end(), b.begin(), b.end());
+        return *this;
+    }
+
+    friend CScript operator+(const CScript& a, const CScript& b)
+    {
+        CScript ret = a;
+        ret += b;
+        return ret;
+    }
+
+    CScript(int64_t b)        { operator<<(b); }
+
+    explicit CScript(opcodetype b)     { operator<<(b); }
+    explicit CScript(const uint256& b) { operator<<(b); }
+    explicit CScript(const CScriptNum& b) { operator<<(b); }
+    explicit CScript(const std::vector<unsigned char>& b) { operator<<(b); }
+
+
+    CScript& operator<<(int64_t b) { return push_int64(b); }
+
+    CScript& operator<<(opcodetype opcode)
+    {
+        if (opcode < 0 || opcode > 0xff)
+            throw std::runtime_error("CScript::operator<<() : invalid opcode");
+        insert(end(), (unsigned char)opcode);
+        return *this;
+    }
+
+    CScript& operator<<(const uint160& b)
+    {
+        insert(end(), sizeof(b));
+        insert(end(), (unsigned char*)&b, (unsigned char*)&b + sizeof(b));
+        return *this;
+    }
+
+    CScript& operator<<(const uint256& b)
+    {
+        insert(end(), sizeof(b));
+        insert(end(), (unsigned char*)&b, (unsigned char*)&b + sizeof(b));
+        return *this;
+    }
+
+    CScript& operator<<(const CPubKey& key)
+    {
+        assert(key.size() < OP_PUSHDATA1);
+        insert(end(), (unsigned char)key.size());
+        insert(end(), key.begin(), key.end());
+        return *this;
+    }
+
+    CScript& operator<<(const CScriptNum& b)
+    {
+        *this << b.getvch();
+        return *this;
+    }
+
+    CScript& operator<<(const std::vector<unsigned char>& b)
+    {
+        if (b.size() < OP_PUSHDATA1)
+        {
+            insert(end(), (unsigned char)b.size());
+        }
+        else if (b.size() <= 0xff)
+        {
+            insert(end(), OP_PUSHDATA1);
+            insert(end(), (unsigned char)b.size());
+        }
+        else if (b.size() <= 0xffff)
+        {
+            insert(end(), OP_PUSHDATA2);
+            unsigned short nSize = b.size();
+            insert(end(), (unsigned char*)&nSize, (unsigned char*)&nSize + sizeof(nSize));
+        }
+        else
+        {
+            insert(end(), OP_PUSHDATA4);
+            unsigned int nSize = b.size();
+            insert(end(), (unsigned char*)&nSize, (unsigned char*)&nSize + sizeof(nSize));
+        }
+        insert(end(), b.begin(), b.end());
+        return *this;
+    }
+
+    CScript& operator<<(const CScript& b)
+    {
+        // I'm not sure if this should push the script or concatenate scripts.
+        // If there's ever a use for pushing a script onto a script, delete this member fn
+        assert(!"Warning: Pushing a CScript onto a CScript with << is probably not intended, use + to concatenate!");
+        return *this;
+    }
+
+
+    bool GetOp(iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet)
+    {
+         // Wrapper so it can be called with either iterator or const_iterator
+         const_iterator pc2 = pc;
+         bool fRet = GetOp2(pc2, opcodeRet, &vchRet);
+         pc = begin() + (pc2 - begin());
+         return fRet;
+    }
+
+    bool GetOp(iterator& pc, opcodetype& opcodeRet)
+    {
+         const_iterator pc2 = pc;
+         bool fRet = GetOp2(pc2, opcodeRet, NULL);
+         pc = begin() + (pc2 - begin());
+         return fRet;
+    }
+
+    bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
+    {
+        return GetOp2(pc, opcodeRet, &vchRet);
+    }
+
+    bool GetOp(const_iterator& pc, opcodetype& opcodeRet) const
+    {
+        return GetOp2(pc, opcodeRet, NULL);
+    }
+
+    bool GetOp2(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>* pvchRet) const
+    {
+        opcodeRet = OP_INVALIDOPCODE;
+        if (pvchRet)
+            pvchRet->clear();
+        if (pc >= end())
+            return false;
+
+        // Read instruction
+        if (end() - pc < 1)
+            return false;
+        unsigned int opcode = *pc++;
+
+        // Immediate operand
+        if (opcode <= OP_PUSHDATA4)
+        {
+            unsigned int nSize = 0;
+            if (opcode < OP_PUSHDATA1)
+            {
+                nSize = opcode;
+            }
+            else if (opcode == OP_PUSHDATA1)
+            {
+                if (end() - pc < 1)
+                    return false;
+                nSize = *pc++;
+            }
+            else if (opcode == OP_PUSHDATA2)
+            {
+                if (end() - pc < 2)
+                    return false;
+                nSize = 0;
+                memcpy(&nSize, &pc[0], 2);
+                pc += 2;
+            }
+            else if (opcode == OP_PUSHDATA4)
+            {
+                if (end() - pc < 4)
+                    return false;
+                memcpy(&nSize, &pc[0], 4);
+                pc += 4;
+            }
+            if (end() - pc < 0 || (unsigned int)(end() - pc) < nSize)
+                return false;
+            if (pvchRet)
+                pvchRet->assign(pc, pc + nSize);
+            pc += nSize;
+        }
+
+        opcodeRet = (opcodetype)opcode;
+        return true;
+    }
+
+    // Encode/decode small integers:
+    static int DecodeOP_N(opcodetype opcode)
+    {
+        if (opcode == OP_0)
+            return 0;
+        assert(opcode >= OP_1 && opcode <= OP_16);
+        return (int)opcode - (int)(OP_1 - 1);
+    }
+    static opcodetype EncodeOP_N(int n)
+    {
+        assert(n >= 0 && n <= 16);
+        if (n == 0)
+            return OP_0;
+        return (opcodetype)(OP_1+n-1);
+    }
+
+    int FindAndDelete(const CScript& b)
+    {
+        int nFound = 0;
+        if (b.empty())
+            return nFound;
+        iterator pc = begin();
+        opcodetype opcode;
+        do
+        {
+            while (end() - pc >= (long)b.size() && memcmp(&pc[0], &b[0], b.size()) == 0)
+            {
+                erase(pc, pc + b.size());
+                ++nFound;
+            }
+        }
+        while (GetOp(pc, opcode));
+        return nFound;
+    }
+    int Find(opcodetype op) const
+    {
+        int nFound = 0;
+        opcodetype opcode;
+        for (const_iterator pc = begin(); pc != end() && GetOp(pc, opcode);)
+            if (opcode == op)
+                ++nFound;
+        return nFound;
+    }
+
+    // Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
+    // as 20 sigops. With pay-to-script-hash, that changed:
+    // CHECKMULTISIGs serialized in scriptSigs are
+    // counted more accurately, assuming they are of the form
+    //  ... OP_N CHECKMULTISIG ...
+    unsigned int GetSigOpCount(bool fAccurate) const;
+
+    // Accurately count sigOps, including sigOps in
+    // pay-to-script-hash transactions:
+    unsigned int GetSigOpCount(const CScript& scriptSig) const;
+
+    bool IsPayToScriptHash() const;
+
+    // Called by IsStandardTx and P2SH VerifyScript (which makes it consensus-critical).
+    bool IsPushOnly() const;
+
+    // Called by IsStandardTx.
+    bool HasCanonicalPushes() const;
+
+    // Returns whether the script is guaranteed to fail at execution,
+    // regardless of the initial stack. This allows outputs to be pruned
+    // instantly when entering the UTXO set.
+    bool IsUnspendable() const
+    {
+        return (size() > 0 && *begin() == OP_RETURN);
+    }
+
+    void SetDestination(const CTxDestination& address);
+    void SetMultisig(int nRequired, const std::vector<CPubKey>& keys);
+
+    std::string ToString() const
+    {
+        std::string str;
+        opcodetype opcode;
+        std::vector<unsigned char> vch;
+        const_iterator pc = begin();
+        while (pc < end())
+        {
+            if (!str.empty())
+                str += " ";
+            if (!GetOp(pc, opcode, vch))
+            {
+                str += "[error]";
+                return str;
+            }
+            if (0 <= opcode && opcode <= OP_PUSHDATA4)
+                str += ValueString(vch);
+            else
+                str += GetOpName(opcode);
+        }
+        return str;
+    }
+
+    CScriptID GetID() const
+    {
+        return CScriptID(Hash160(*this));
+    }
+
+    void clear()
+    {
+        // The default std::vector::clear() does not release memory.
+        std::vector<unsigned char>().swap(*this);
+    }
+};
+
+#endif