Merge pull request bitcoin#3965

b1fdd54 script: Add test for CScriptNum (Cory Fields) 90320d6 script: add additional script tests (Cory Fields) 05e3ecf script: remove bignum dependency (Cory Fields) 4f497cd script: switch outside users to CScriptNum (Cory Fields) 27bff74 script: switch to CScriptNum usage for scripts (Cory Fields) 48d8eb1 script: add CScriptNum class (Cory Fields)
thams · May 9, 2014 · 1c0319b · 1c0319b
2 parents d54985f + b1fdd54
commit 1c0319b
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Showing 8 changed files with 387 additions and 73 deletions.
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
@@ -125,7 +125,7 @@ class CMainParams : public CChainParams {
         CTransaction txNew;
         txNew.vin.resize(1);
         txNew.vout.resize(1);
-        txNew.vin[0].scriptSig = CScript() << 486604799 << CBigNum(4) << vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
+        txNew.vin[0].scriptSig = CScript() << 486604799 << CScriptNum(4) << vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
         txNew.vout[0].nValue = 50 * COIN;
         txNew.vout[0].scriptPubKey = CScript() << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f") << OP_CHECKSIG;
         genesis.vtx.push_back(txNew);

diff --git a/src/miner.cpp b/src/miner.cpp
@@ -355,7 +355,7 @@ void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int&
     }
     ++nExtraNonce;
     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
-    pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CBigNum(nExtraNonce)) + COINBASE_FLAGS;
+    pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
     assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
 
     pblock->hashMerkleRoot = pblock->BuildMerkleTree();

diff --git a/src/script.cpp b/src/script.cpp
@@ -5,7 +5,6 @@
 
 #include "script.h"
 
-#include "bignum.h"
 #include "core.h"
 #include "hash.h"
 #include "key.h"
@@ -25,22 +24,13 @@ typedef vector<unsigned char> valtype;
 static const valtype vchFalse(0);
 static const valtype vchZero(0);
 static const valtype vchTrue(1, 1);
-static const CBigNum bnZero(0);
-static const CBigNum bnOne(1);
-static const CBigNum bnFalse(0);
-static const CBigNum bnTrue(1);
-static const size_t nMaxNumSize = 4;
+static const CScriptNum bnZero(0);
+static const CScriptNum bnOne(1);
+static const CScriptNum bnFalse(0);
+static const CScriptNum bnTrue(1);
 
 bool CheckSig(vector<unsigned char> vchSig, const vector<unsigned char> &vchPubKey, const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, int flags);
 
-CBigNum CastToBigNum(const valtype& vch)
-{
-    if (vch.size() > nMaxNumSize)
-        throw runtime_error("CastToBigNum() : overflow");
-    // Get rid of extra leading zeros
-    return CBigNum(CBigNum(vch).getvch());
-}
-
 bool CastToBool(const valtype& vch)
 {
     for (unsigned int i = 0; i < vch.size(); i++)
@@ -306,7 +296,6 @@ bool IsCanonicalSignature(const valtype &vchSig, unsigned int flags) {
 
 bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType)
 {
-    CAutoBN_CTX pctx;
     CScript::const_iterator pc = script.begin();
     CScript::const_iterator pend = script.end();
     CScript::const_iterator pbegincodehash = script.begin();
@@ -380,7 +369,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                 case OP_16:
                 {
                     // ( -- value)
-                    CBigNum bn((int)opcode - (int)(OP_1 - 1));
+                    CScriptNum bn((int)opcode - (int)(OP_1 - 1));
                     stack.push_back(bn.getvch());
                 }
                 break;
@@ -556,7 +545,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                 case OP_DEPTH:
                 {
                     // -- stacksize
-                    CBigNum bn(stack.size());
+                    CScriptNum bn(stack.size());
                     stack.push_back(bn.getvch());
                 }
                 break;
@@ -606,7 +595,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
                     if (stack.size() < 2)
                         return false;
-                    int n = CastToBigNum(stacktop(-1)).getint();
+                    int n = CScriptNum(stacktop(-1)).getint();
                     popstack(stack);
                     if (n < 0 || n >= (int)stack.size())
                         return false;
@@ -654,7 +643,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     // (in -- in size)
                     if (stack.size() < 1)
                         return false;
-                    CBigNum bn(stacktop(-1).size());
+                    CScriptNum bn(stacktop(-1).size());
                     stack.push_back(bn.getvch());
                 }
                 break;
@@ -705,7 +694,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     // (in -- out)
                     if (stack.size() < 1)
                         return false;
-                    CBigNum bn = CastToBigNum(stacktop(-1));
+                    CScriptNum bn(stacktop(-1));
                     switch (opcode)
                     {
                     case OP_1ADD:       bn += bnOne; break;
@@ -738,9 +727,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     // (x1 x2 -- out)
                     if (stack.size() < 2)
                         return false;
-                    CBigNum bn1 = CastToBigNum(stacktop(-2));
-                    CBigNum bn2 = CastToBigNum(stacktop(-1));
-                    CBigNum bn;
+                    CScriptNum bn1(stacktop(-2));
+                    CScriptNum bn2(stacktop(-1));
+                    CScriptNum bn(0);
                     switch (opcode)
                     {
                     case OP_ADD:
@@ -783,9 +772,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     // (x min max -- out)
                     if (stack.size() < 3)
                         return false;
-                    CBigNum bn1 = CastToBigNum(stacktop(-3));
-                    CBigNum bn2 = CastToBigNum(stacktop(-2));
-                    CBigNum bn3 = CastToBigNum(stacktop(-1));
+                    CScriptNum bn1(stacktop(-3));
+                    CScriptNum bn2(stacktop(-2));
+                    CScriptNum bn3(stacktop(-1));
                     bool fValue = (bn2 <= bn1 && bn1 < bn3);
                     popstack(stack);
                     popstack(stack);
@@ -882,7 +871,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     if ((int)stack.size() < i)
                         return false;
 
-                    int nKeysCount = CastToBigNum(stacktop(-i)).getint();
+                    int nKeysCount = CScriptNum(stacktop(-i)).getint();
                     if (nKeysCount < 0 || nKeysCount > 20)
                         return false;
                     nOpCount += nKeysCount;
@@ -893,7 +882,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co
                     if ((int)stack.size() < i)
                         return false;
 
-                    int nSigsCount = CastToBigNum(stacktop(-i)).getint();
+                    int nSigsCount = CScriptNum(stacktop(-i)).getint();
                     if (nSigsCount < 0 || nSigsCount > nKeysCount)
                         return false;
                     int isig = ++i;

diff --git a/src/script.h b/src/script.h
@@ -6,7 +6,6 @@
 #ifndef H_BITCOIN_SCRIPT
 #define H_BITCOIN_SCRIPT
 
-#include "bignum.h"
 #include "key.h"
 #include "util.h"
 
@@ -25,6 +24,155 @@ class CTransaction;
 static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520; // bytes
 static const unsigned int MAX_OP_RETURN_RELAY = 40;      // bytes
 
+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 & ~(0x80 << (8 * (vch.size() - 1))));
+
+      return result;
+    }
+
+    int64_t m_value;
+};
+
 /** Signature hash types/flags */
 enum
 {
@@ -225,7 +373,7 @@ const char* GetOpName(opcodetype opcode);
 inline std::string ValueString(const std::vector<unsigned char>& vch)
 {
     if (vch.size() <= 4)
-        return strprintf("%d", CBigNum(vch).getint());
+        return strprintf("%d", CScriptNum(vch).getint());
     else
         return HexStr(vch);
 }
@@ -261,26 +409,10 @@ class CScript : public std::vector<unsigned char>
         }
         else
         {
-            CBigNum bn(n);
-            *this << bn.getvch();
+            *this << CScriptNum::serialize(n);
         }
         return *this;
     }
-
-    CScript& push_uint64(uint64_t n)
-    {
-        if (n >= 1 && n <= 16)
-        {
-            push_back(n + (OP_1 - 1));
-        }
-        else
-        {
-            CBigNum bn(n);
-            *this << bn.getvch();
-        }
-        return *this;
-    }
-
 public:
     CScript() { }
     CScript(const CScript& b) : std::vector<unsigned char>(b.begin(), b.end()) { }
@@ -303,35 +435,15 @@ class CScript : public std::vector<unsigned char>
     }
 
 
-    //explicit CScript(char b) is not portable.  Use 'signed char' or 'unsigned char'.
-    explicit CScript(signed char b)        { operator<<(b); }
-    explicit CScript(short b)              { operator<<(b); }
-    explicit CScript(int b)                { operator<<(b); }
-    explicit CScript(long b)               { operator<<(b); }
-    explicit CScript(long long b)          { operator<<(b); }
-    explicit CScript(unsigned char b)      { operator<<(b); }
-    explicit CScript(unsigned int b)       { operator<<(b); }
-    explicit CScript(unsigned short b)     { operator<<(b); }
-    explicit CScript(unsigned long b)      { operator<<(b); }
-    explicit CScript(unsigned long long b) { operator<<(b); }
+    CScript(int64_t b)        { operator<<(b); }
 
     explicit CScript(opcodetype b)     { operator<<(b); }
     explicit CScript(const uint256& b) { operator<<(b); }
-    explicit CScript(const CBigNum& b) { operator<<(b); }
+    explicit CScript(const CScriptNum& b) { operator<<(b); }
     explicit CScript(const std::vector<unsigned char>& b) { operator<<(b); }
 
 
-    //CScript& operator<<(char b) is not portable.  Use 'signed char' or 'unsigned char'.
-    CScript& operator<<(signed char b)        { return push_int64(b); }
-    CScript& operator<<(short b)              { return push_int64(b); }
-    CScript& operator<<(int b)                { return push_int64(b); }
-    CScript& operator<<(long b)               { return push_int64(b); }
-    CScript& operator<<(long long b)          { return push_int64(b); }
-    CScript& operator<<(unsigned char b)      { return push_uint64(b); }
-    CScript& operator<<(unsigned int b)       { return push_uint64(b); }
-    CScript& operator<<(unsigned short b)     { return push_uint64(b); }
-    CScript& operator<<(unsigned long b)      { return push_uint64(b); }
-    CScript& operator<<(unsigned long long b) { return push_uint64(b); }
+    CScript& operator<<(int64_t b) { return push_int64(b); }
 
     CScript& operator<<(opcodetype opcode)
     {
@@ -363,7 +475,7 @@ class CScript : public std::vector<unsigned char>
         return *this;
     }
 
-    CScript& operator<<(const CBigNum& b)
+    CScript& operator<<(const CScriptNum& b)
     {
         *this << b.getvch();
         return *this;