uint256->arith_uint256 blob256->uint256

Introduce new opaque implementation of `uint256`, move old
"arithmetic" implementation to `arith_uint256.

1 files changed, 341 insertions, 10 deletions

diff --git a/src/arith_uint256.h b/src/arith_uint256.h
index 3bb384ca8a..9e32b124c2 100644
--- a/src/arith_uint256.h
+++ b/src/arith_uint256.h
@@ -1,19 +1,350 @@
+// 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.
+
 #ifndef BITCOIN_ARITH_UINT256_H
 #define BITCOIN_ARITH_UINT256_H
 
-// Temporary for migration to opaque uint160/256
-#include "uint256.h"
+#include <assert.h>
+#include <cstring>
+#include <stdexcept>
+#include <stdint.h>
+#include <string>
+#include <vector>
 
-class arith_uint256 : public uint256 {
+class uint_error : public std::runtime_error {
 public:
-    arith_uint256() {}
-    arith_uint256(const base_uint<256>& b) : uint256(b) {}
-    arith_uint256(uint64_t b) : uint256(b) {}
-    explicit arith_uint256(const std::string& str) : uint256(str) {}
-    explicit arith_uint256(const std::vector<unsigned char>& vch) : uint256(vch) {}
+    explicit uint_error(const std::string& str) : std::runtime_error(str) {}
+};
+
+/** Template base class for unsigned big integers. */
+template<unsigned int BITS>
+class base_uint
+{
+protected:
+    enum { WIDTH=BITS/32 };
+    uint32_t pn[WIDTH];
+public:
+
+    base_uint()
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] = 0;
+    }
+
+    base_uint(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] = b.pn[i];
+    }
+
+    base_uint& operator=(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] = b.pn[i];
+        return *this;
+    }
+
+    base_uint(uint64_t b)
+    {
+        pn[0] = (unsigned int)b;
+        pn[1] = (unsigned int)(b >> 32);
+        for (int i = 2; i < WIDTH; i++)
+            pn[i] = 0;
+    }
+
+    explicit base_uint(const std::string& str);
+    explicit base_uint(const std::vector<unsigned char>& vch);
+
+    bool operator!() const
+    {
+        for (int i = 0; i < WIDTH; i++)
+            if (pn[i] != 0)
+                return false;
+        return true;
+    }
+
+    const base_uint operator~() const
+    {
+        base_uint ret;
+        for (int i = 0; i < WIDTH; i++)
+            ret.pn[i] = ~pn[i];
+        return ret;
+    }
+
+    const base_uint operator-() const
+    {
+        base_uint ret;
+        for (int i = 0; i < WIDTH; i++)
+            ret.pn[i] = ~pn[i];
+        ret++;
+        return ret;
+    }
+
+    double getdouble() const;
+
+    base_uint& operator=(uint64_t b)
+    {
+        pn[0] = (unsigned int)b;
+        pn[1] = (unsigned int)(b >> 32);
+        for (int i = 2; i < WIDTH; i++)
+            pn[i] = 0;
+        return *this;
+    }
+
+    base_uint& operator^=(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] ^= b.pn[i];
+        return *this;
+    }
+
+    base_uint& operator&=(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] &= b.pn[i];
+        return *this;
+    }
+
+    base_uint& operator|=(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] |= b.pn[i];
+        return *this;
+    }
+
+    base_uint& operator^=(uint64_t b)
+    {
+        pn[0] ^= (unsigned int)b;
+        pn[1] ^= (unsigned int)(b >> 32);
+        return *this;
+    }
+
+    base_uint& operator|=(uint64_t b)
+    {
+        pn[0] |= (unsigned int)b;
+        pn[1] |= (unsigned int)(b >> 32);
+        return *this;
+    }
+
+    base_uint& operator<<=(unsigned int shift);
+    base_uint& operator>>=(unsigned int shift);
+
+    base_uint& operator+=(const base_uint& b)
+    {
+        uint64_t carry = 0;
+        for (int i = 0; i < WIDTH; i++)
+        {
+            uint64_t n = carry + pn[i] + b.pn[i];
+            pn[i] = n & 0xffffffff;
+            carry = n >> 32;
+        }
+        return *this;
+    }
+
+    base_uint& operator-=(const base_uint& b)
+    {
+        *this += -b;
+        return *this;
+    }
+
+    base_uint& operator+=(uint64_t b64)
+    {
+        base_uint b;
+        b = b64;
+        *this += b;
+        return *this;
+    }
+
+    base_uint& operator-=(uint64_t b64)
+    {
+        base_uint b;
+        b = b64;
+        *this += -b;
+        return *this;
+    }
+
+    base_uint& operator*=(uint32_t b32);
+    base_uint& operator*=(const base_uint& b);
+    base_uint& operator/=(const base_uint& b);
+
+    base_uint& operator++()
+    {
+        // prefix operator
+        int i = 0;
+        while (++pn[i] == 0 && i < WIDTH-1)
+            i++;
+        return *this;
+    }
+
+    const base_uint operator++(int)
+    {
+        // postfix operator
+        const base_uint ret = *this;
+        ++(*this);
+        return ret;
+    }
+
+    base_uint& operator--()
+    {
+        // prefix operator
+        int i = 0;
+        while (--pn[i] == (uint32_t)-1 && i < WIDTH-1)
+            i++;
+        return *this;
+    }
+
+    const base_uint operator--(int)
+    {
+        // postfix operator
+        const base_uint ret = *this;
+        --(*this);
+        return ret;
+    }
+
+    int CompareTo(const base_uint& b) const;
+    bool EqualTo(uint64_t b) const;
+
+    friend inline const base_uint operator+(const base_uint& a, const base_uint& b) { return base_uint(a) += b; }
+    friend inline const base_uint operator-(const base_uint& a, const base_uint& b) { return base_uint(a) -= b; }
+    friend inline const base_uint operator*(const base_uint& a, const base_uint& b) { return base_uint(a) *= b; }
+    friend inline const base_uint operator/(const base_uint& a, const base_uint& b) { return base_uint(a) /= b; }
+    friend inline const base_uint operator|(const base_uint& a, const base_uint& b) { return base_uint(a) |= b; }
+    friend inline const base_uint operator&(const base_uint& a, const base_uint& b) { return base_uint(a) &= b; }
+    friend inline const base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
+    friend inline const base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
+    friend inline const base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }
+    friend inline const base_uint operator*(const base_uint& a, uint32_t b) { return base_uint(a) *= b; }
+    friend inline bool operator==(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0; }
+    friend inline bool operator!=(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0; }
+    friend inline bool operator>(const base_uint& a, const base_uint& b) { return a.CompareTo(b) > 0; }
+    friend inline bool operator<(const base_uint& a, const base_uint& b) { return a.CompareTo(b) < 0; }
+    friend inline bool operator>=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) >= 0; }
+    friend inline bool operator<=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) <= 0; }
+    friend inline bool operator==(const base_uint& a, uint64_t b) { return a.EqualTo(b); }
+    friend inline bool operator!=(const base_uint& a, uint64_t b) { return !a.EqualTo(b); }
+
+    std::string GetHex() const;
+    void SetHex(const char* psz);
+    void SetHex(const std::string& str);
+    std::string ToString() const;
+
+    unsigned char* begin()
+    {
+        return (unsigned char*)&pn[0];
+    }
+
+    unsigned char* end()
+    {
+        return (unsigned char*)&pn[WIDTH];
+    }
+
+    const unsigned char* begin() const
+    {
+        return (unsigned char*)&pn[0];
+    }
+
+    const unsigned char* end() const
+    {
+        return (unsigned char*)&pn[WIDTH];
+    }
+
+    unsigned int size() const
+    {
+        return sizeof(pn);
+    }
+
+    /**
+     * Returns the position of the highest bit set plus one, or zero if the
+     * value is zero.
+     */
+    unsigned int bits() const;
+
+    uint64_t GetLow64() const
+    {
+        assert(WIDTH >= 2);
+        return pn[0] | (uint64_t)pn[1] << 32;
+    }
+
+    unsigned int GetSerializeSize(int nType, int nVersion) const
+    {
+        return sizeof(pn);
+    }
+
+    template<typename Stream>
+    void Serialize(Stream& s, int nType, int nVersion) const
+    {
+        s.write((char*)pn, sizeof(pn));
+    }
+
+    template<typename Stream>
+    void Unserialize(Stream& s, int nType, int nVersion)
+    {
+        s.read((char*)pn, sizeof(pn));
+    }
+
+    // Temporary for migration to blob160/256
+    uint64_t GetCheapHash() const
+    {
+        return GetLow64();
+    }
+    void SetNull()
+    {
+        memset(pn, 0, sizeof(pn));
+    }
+    bool IsNull() const
+    {
+        for (int i = 0; i < WIDTH; i++)
+            if (pn[i] != 0)
+                return false;
+        return true;
+    }
 };
 
-#define ArithToUint256(x) (x)
-#define UintToArith256(x) (x)
+/** 160-bit unsigned big integer. */
+class arith_uint160 : public base_uint<160> {
+public:
+    arith_uint160() {}
+    arith_uint160(const base_uint<160>& b) : base_uint<160>(b) {}
+    arith_uint160(uint64_t b) : base_uint<160>(b) {}
+    explicit arith_uint160(const std::string& str) : base_uint<160>(str) {}
+    explicit arith_uint160(const std::vector<unsigned char>& vch) : base_uint<160>(vch) {}
+};
+
+/** 256-bit unsigned big integer. */
+class arith_uint256 : public base_uint<256> {
+public:
+    arith_uint256() {}
+    arith_uint256(const base_uint<256>& b) : base_uint<256>(b) {}
+    arith_uint256(uint64_t b) : base_uint<256>(b) {}
+    explicit arith_uint256(const std::string& str) : base_uint<256>(str) {}
+    explicit arith_uint256(const std::vector<unsigned char>& vch) : base_uint<256>(vch) {}
+
+    /**
+     * The "compact" format is a representation of a whole
+     * number N using an unsigned 32bit number similar to a
+     * floating point format.
+     * The most significant 8 bits are the unsigned exponent of base 256.
+     * This exponent can be thought of as "number of bytes of N".
+     * The lower 23 bits are the mantissa.
+     * Bit number 24 (0x800000) represents the sign of N.
+     * N = (-1^sign) * mantissa * 256^(exponent-3)
+     *
+     * Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
+     * MPI uses the most significant bit of the first byte as sign.
+     * Thus 0x1234560000 is compact (0x05123456)
+     * and  0xc0de000000 is compact (0x0600c0de)
+     *
+     * Bitcoin only uses this "compact" format for encoding difficulty
+     * targets, which are unsigned 256bit quantities.  Thus, all the
+     * complexities of the sign bit and using base 256 are probably an
+     * implementation accident.
+     */
+    arith_uint256& SetCompact(uint32_t nCompact, bool *pfNegative = NULL, bool *pfOverflow = NULL);
+    uint32_t GetCompact(bool fNegative = false) const;
+
+    uint64_t GetHash(const arith_uint256& salt) const;
+};
 
 #endif // BITCOIN_UINT256_H