Replace scriptnum_test's normative ScriptNum implementation

Compare against the scriptnum from Bitcoin Core 0.10 instead of OpenSSL.
Closes #7086.

4 files changed, 206 insertions, 200 deletions

diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index 2328d0b4cc..fafc1a2944 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -35,7 +35,7 @@ GENERATED_TEST_FILES = $(JSON_TEST_FILES:.json=.json.h) $(RAW_TEST_FILES:.raw=.r
 
 BITCOIN_TESTS =\
   test/arith_uint256_tests.cpp \
-  test/bignum.h \
+  test/scriptnum10.h \
   test/addrman_tests.cpp \
   test/alert_tests.cpp \
   test/allocator_tests.cpp \
diff --git a/src/test/bignum.h b/src/test/bignum.h
deleted file mode 100644
index e7aeee9db6..0000000000
--- a/src/test/bignum.h
+++ /dev/null
@@ -1,180 +0,0 @@
-// Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2013 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_TEST_BIGNUM_H
-#define BITCOIN_TEST_BIGNUM_H
-
-#include <algorithm>
-#include <limits>
-#include <stdexcept>
-#include <stdint.h>
-#include <string>
-#include <vector>
-
-#include <openssl/bn.h>
-
-class bignum_error : public std::runtime_error
-{
-public:
-    explicit bignum_error(const std::string& str) : std::runtime_error(str) {}
-};
-
-
-/** C++ wrapper for BIGNUM (OpenSSL bignum) */
-class CBigNum : public BIGNUM
-{
-public:
-    CBigNum()
-    {
-        BN_init(this);
-    }
-
-    CBigNum(const CBigNum& b)
-    {
-        BN_init(this);
-        if (!BN_copy(this, &b))
-        {
-            BN_clear_free(this);
-            throw bignum_error("CBigNum::CBigNum(const CBigNum&): BN_copy failed");
-        }
-    }
-
-    CBigNum& operator=(const CBigNum& b)
-    {
-        if (!BN_copy(this, &b))
-            throw bignum_error("CBigNum::operator=: BN_copy failed");
-        return (*this);
-    }
-
-    ~CBigNum()
-    {
-        BN_clear_free(this);
-    }
-
-    CBigNum(long long n)          { BN_init(this); setint64(n); }
-
-    explicit CBigNum(const std::vector<unsigned char>& vch)
-    {
-        BN_init(this);
-        setvch(vch);
-    }
-
-    int getint() const
-    {
-        BN_ULONG n = BN_get_word(this);
-        if (!BN_is_negative(this))
-            return (n > (BN_ULONG)std::numeric_limits<int>::max() ? std::numeric_limits<int>::max() : n);
-        else
-            return (n > (BN_ULONG)std::numeric_limits<int>::max() ? std::numeric_limits<int>::min() : -(int)n);
-    }
-
-    void setint64(int64_t sn)
-    {
-        unsigned char pch[sizeof(sn) + 6];
-        unsigned char* p = pch + 4;
-        bool fNegative;
-        uint64_t n;
-
-        if (sn < (int64_t)0)
-        {
-            // Since the minimum signed integer cannot be represented as positive so long as its type is signed, 
-            // and it's not well-defined what happens if you make it unsigned before negating it,
-            // we instead increment the negative integer by 1, convert it, then increment the (now positive) unsigned integer by 1 to compensate
-            n = -(sn + 1);
-            ++n;
-            fNegative = true;
-        } else {
-            n = sn;
-            fNegative = false;
-        }
-
-        bool fLeadingZeroes = true;
-        for (int i = 0; i < 8; i++)
-        {
-            unsigned char c = (n >> 56) & 0xff;
-            n <<= 8;
-            if (fLeadingZeroes)
-            {
-                if (c == 0)
-                    continue;
-                if (c & 0x80)
-                    *p++ = (fNegative ? 0x80 : 0);
-                else if (fNegative)
-                    c |= 0x80;
-                fLeadingZeroes = false;
-            }
-            *p++ = c;
-        }
-        unsigned int nSize = p - (pch + 4);
-        pch[0] = (nSize >> 24) & 0xff;
-        pch[1] = (nSize >> 16) & 0xff;
-        pch[2] = (nSize >> 8) & 0xff;
-        pch[3] = (nSize) & 0xff;
-        BN_mpi2bn(pch, p - pch, this);
-    }
-
-    void setvch(const std::vector<unsigned char>& vch)
-    {
-        std::vector<unsigned char> vch2(vch.size() + 4);
-        unsigned int nSize = vch.size();
-        // BIGNUM's byte stream format expects 4 bytes of
-        // big endian size data info at the front
-        vch2[0] = (nSize >> 24) & 0xff;
-        vch2[1] = (nSize >> 16) & 0xff;
-        vch2[2] = (nSize >> 8) & 0xff;
-        vch2[3] = (nSize >> 0) & 0xff;
-        // swap data to big endian
-        reverse_copy(vch.begin(), vch.end(), vch2.begin() + 4);
-        BN_mpi2bn(&vch2[0], vch2.size(), this);
-    }
-
-    std::vector<unsigned char> getvch() const
-    {
-        unsigned int nSize = BN_bn2mpi(this, NULL);
-        if (nSize <= 4)
-            return std::vector<unsigned char>();
-        std::vector<unsigned char> vch(nSize);
-        BN_bn2mpi(this, &vch[0]);
-        vch.erase(vch.begin(), vch.begin() + 4);
-        reverse(vch.begin(), vch.end());
-        return vch;
-    }
-
-    friend inline const CBigNum operator-(const CBigNum& a, const CBigNum& b);
-};
-
-
-
-inline const CBigNum operator+(const CBigNum& a, const CBigNum& b)
-{
-    CBigNum r;
-    if (!BN_add(&r, &a, &b))
-        throw bignum_error("CBigNum::operator+: BN_add failed");
-    return r;
-}
-
-inline const CBigNum operator-(const CBigNum& a, const CBigNum& b)
-{
-    CBigNum r;
-    if (!BN_sub(&r, &a, &b))
-        throw bignum_error("CBigNum::operator-: BN_sub failed");
-    return r;
-}
-
-inline const CBigNum operator-(const CBigNum& a)
-{
-    CBigNum r(a);
-    BN_set_negative(&r, !BN_is_negative(&r));
-    return r;
-}
-
-inline bool operator==(const CBigNum& a, const CBigNum& b) { return (BN_cmp(&a, &b) == 0); }
-inline bool operator!=(const CBigNum& a, const CBigNum& b) { return (BN_cmp(&a, &b) != 0); }
-inline bool operator<=(const CBigNum& a, const CBigNum& b) { return (BN_cmp(&a, &b) <= 0); }
-inline bool operator>=(const CBigNum& a, const CBigNum& b) { return (BN_cmp(&a, &b) >= 0); }
-inline bool operator<(const CBigNum& a, const CBigNum& b)  { return (BN_cmp(&a, &b) < 0); }
-inline bool operator>(const CBigNum& a, const CBigNum& b)  { return (BN_cmp(&a, &b) > 0); }
-
-#endif // BITCOIN_TEST_BIGNUM_H
diff --git a/src/test/scriptnum10.h b/src/test/scriptnum10.h
new file mode 100644
index 0000000000..00419746b7
--- /dev/null
+++ b/src/test/scriptnum10.h
@@ -0,0 +1,183 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 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_TEST_SCRIPTNUM10_H
+#define BITCOIN_TEST_SCRIPTNUM10_H
+
+#include <algorithm>
+#include <limits>
+#include <stdexcept>
+#include <stdint.h>
+#include <string>
+#include <vector>
+#include "assert.h"
+
+class scriptnum10_error : public std::runtime_error
+{
+public:
+    explicit scriptnum10_error(const std::string& str) : std::runtime_error(str) {}
+};
+
+class CScriptNum10
+{
+/**
+ * The ScriptNum implementation from Bitcoin Core 0.10.0, for cross-comparison.
+ */
+public:
+
+    explicit CScriptNum10(const int64_t& n)
+    {
+        m_value = n;
+    }
+
+    static const size_t nDefaultMaxNumSize = 4;
+
+    explicit CScriptNum10(const std::vector<unsigned char>& vch, bool fRequireMinimal,
+                        const size_t nMaxNumSize = nDefaultMaxNumSize)
+    {
+        if (vch.size() > nMaxNumSize) {
+            throw scriptnum10_error("script number overflow");
+        }
+        if (fRequireMinimal && vch.size() > 0) {
+            // Check that the number is encoded with the minimum possible
+            // number of bytes.
+            //
+            // If the most-significant-byte - excluding the sign bit - is zero
+            // then we're not minimal. Note how this test also rejects the
+            // negative-zero encoding, 0x80.
+            if ((vch.back() & 0x7f) == 0) {
+                // One exception: if there's more than one byte and the most
+                // significant bit of the second-most-significant-byte is set
+                // it would conflict with the sign bit. An example of this case
+                // is +-255, which encode to 0xff00 and 0xff80 respectively.
+                // (big-endian).
+                if (vch.size() <= 1 || (vch[vch.size() - 2] & 0x80) == 0) {
+                    throw scriptnum10_error("non-minimally encoded script number");
+                }
+            }
+        }
+        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 CScriptNum10& rhs) const { return operator==(rhs.m_value); }
+    inline bool operator!=(const CScriptNum10& rhs) const { return operator!=(rhs.m_value); }
+    inline bool operator<=(const CScriptNum10& rhs) const { return operator<=(rhs.m_value); }
+    inline bool operator< (const CScriptNum10& rhs) const { return operator< (rhs.m_value); }
+    inline bool operator>=(const CScriptNum10& rhs) const { return operator>=(rhs.m_value); }
+    inline bool operator> (const CScriptNum10& rhs) const { return operator> (rhs.m_value); }
+
+    inline CScriptNum10 operator+(   const int64_t& rhs)    const { return CScriptNum10(m_value + rhs);}
+    inline CScriptNum10 operator-(   const int64_t& rhs)    const { return CScriptNum10(m_value - rhs);}
+    inline CScriptNum10 operator+(   const CScriptNum10& rhs) const { return operator+(rhs.m_value);   }
+    inline CScriptNum10 operator-(   const CScriptNum10& rhs) const { return operator-(rhs.m_value);   }
+
+    inline CScriptNum10& operator+=( const CScriptNum10& rhs)       { return operator+=(rhs.m_value);  }
+    inline CScriptNum10& operator-=( const CScriptNum10& rhs)       { return operator-=(rhs.m_value);  }
+
+    inline CScriptNum10 operator-()                         const
+    {
+        assert(m_value != std::numeric_limits<int64_t>::min());
+        return CScriptNum10(-m_value);
+    }
+
+    inline CScriptNum10& operator=( const int64_t& rhs)
+    {
+        m_value = rhs;
+        return *this;
+    }
+
+    inline CScriptNum10& 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 CScriptNum10& 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;
+    }
+
+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 -((int64_t)(result & ~(0x80ULL << (8 * (vch.size() - 1)))));
+
+      return result;
+    }
+
+    int64_t m_value;
+};
+
+
+#endif // BITCOIN_TEST_BIGNUM_H
diff --git a/src/test/scriptnum_tests.cpp b/src/test/scriptnum_tests.cpp
index d95724dbe1..2405ab3ffc 100644
--- a/src/test/scriptnum_tests.cpp
+++ b/src/test/scriptnum_tests.cpp
@@ -2,7 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include "bignum.h"
+#include "scriptnum10.h"
 #include "script/script.h"
 #include "test/test_bitcoin.h"
 
@@ -16,45 +16,48 @@ static const int64_t values[] = \
 { 0, 1, CHAR_MIN, CHAR_MAX, UCHAR_MAX, SHRT_MIN, USHRT_MAX, INT_MIN, INT_MAX, UINT_MAX, LONG_MIN, LONG_MAX };
 static const int64_t offsets[] = { 1, 0x79, 0x80, 0x81, 0xFF, 0x7FFF, 0x8000, 0xFFFF, 0x10000};
 
-static bool verify(const CBigNum& bignum, const CScriptNum& scriptnum)
+static bool verify(const CScriptNum10& bignum, const CScriptNum& scriptnum)
 {
     return bignum.getvch() == scriptnum.getvch() && bignum.getint() == scriptnum.getint();
 }
 
 static void CheckCreateVch(const int64_t& num)
 {
-    CBigNum bignum(num);
+    CScriptNum10 bignum(num);
     CScriptNum scriptnum(num);
     BOOST_CHECK(verify(bignum, scriptnum));
 
-    CBigNum bignum2(bignum.getvch());
+    std::vector<unsigned char> vch = bignum.getvch();
+
+    CScriptNum10 bignum2(bignum.getvch(), false);
+    vch = scriptnum.getvch();
     CScriptNum scriptnum2(scriptnum.getvch(), false);
     BOOST_CHECK(verify(bignum2, scriptnum2));
 
-    CBigNum bignum3(scriptnum2.getvch());
+    CScriptNum10 bignum3(scriptnum2.getvch(), false);
     CScriptNum scriptnum3(bignum2.getvch(), false);
     BOOST_CHECK(verify(bignum3, scriptnum3));
 }
 
 static void CheckCreateInt(const int64_t& num)
 {
-    CBigNum bignum(num);
+    CScriptNum10 bignum(num);
     CScriptNum scriptnum(num);
     BOOST_CHECK(verify(bignum, scriptnum));
-    BOOST_CHECK(verify(bignum.getint(), CScriptNum(scriptnum.getint())));
-    BOOST_CHECK(verify(scriptnum.getint(), CScriptNum(bignum.getint())));
-    BOOST_CHECK(verify(CBigNum(scriptnum.getint()).getint(), CScriptNum(CScriptNum(bignum.getint()).getint())));
+    BOOST_CHECK(verify(CScriptNum10(bignum.getint()), CScriptNum(scriptnum.getint())));
+    BOOST_CHECK(verify(CScriptNum10(scriptnum.getint()), CScriptNum(bignum.getint())));
+    BOOST_CHECK(verify(CScriptNum10(CScriptNum10(scriptnum.getint()).getint()), CScriptNum(CScriptNum(bignum.getint()).getint())));
 }
 
 
 static void CheckAdd(const int64_t& num1, const int64_t& num2)
 {
-    const CBigNum bignum1(num1);
-    const CBigNum bignum2(num2);
+    const CScriptNum10 bignum1(num1);
+    const CScriptNum10 bignum2(num2);
     const CScriptNum scriptnum1(num1);
     const CScriptNum scriptnum2(num2);
-    CBigNum bignum3(num1);
-    CBigNum bignum4(num1);
+    CScriptNum10 bignum3(num1);
+    CScriptNum10 bignum4(num1);
     CScriptNum scriptnum3(num1);
     CScriptNum scriptnum4(num1);
 
@@ -71,7 +74,7 @@ static void CheckAdd(const int64_t& num1, const int64_t& num2)
 
 static void CheckNegate(const int64_t& num)
 {
-    const CBigNum bignum(num);
+    const CScriptNum10 bignum(num);
     const CScriptNum scriptnum(num);
 
     // -INT64_MIN is undefined
@@ -81,8 +84,8 @@ static void CheckNegate(const int64_t& num)
 
 static void CheckSubtract(const int64_t& num1, const int64_t& num2)
 {
-    const CBigNum bignum1(num1);
-    const CBigNum bignum2(num2);
+    const CScriptNum10 bignum1(num1);
+    const CScriptNum10 bignum2(num2);
     const CScriptNum scriptnum1(num1);
     const CScriptNum scriptnum2(num2);
     bool invalid = false;
@@ -107,8 +110,8 @@ static void CheckSubtract(const int64_t& num1, const int64_t& num2)
 
 static void CheckCompare(const int64_t& num1, const int64_t& num2)
 {
-    const CBigNum bignum1(num1);
-    const CBigNum bignum2(num2);
+    const CScriptNum10 bignum1(num1);
+    const CScriptNum10 bignum2(num2);
     const CScriptNum scriptnum1(num1);
     const CScriptNum scriptnum2(num2);
 
@@ -149,7 +152,7 @@ static void RunCreate(const int64_t& num)
         CheckCreateVch(num);
     else
     {
-        BOOST_CHECK_THROW (CheckCreateVch(num), scriptnum_error);
+        BOOST_CHECK_THROW (CheckCreateVch(num), scriptnum10_error);
     }
 }