Merge pull request #5490

6bd0dc2 arith_uint256: remove initialization from byte vector (Wladimir J. van der Laan)
30007fd Remove now-unused methods from arith_uint256 and base_uint (Wladimir J. van der Laan)
edc7204 Remove arith_uint160 (Wladimir J. van der Laan)
dba2e91 Add tests for new uint256 (Wladimir J. van der Laan)
92cdb1a Add conversion functions arith_uint256<->uint_256 (Wladimir J. van der Laan)
bfc6070 uint256->arith_uint256 blob256->uint256 (Wladimir J. van der Laan)
734f85c Use arith_uint256 where necessary (Wladimir J. van der Laan)
34cdc41 String conversions uint256 -> uint256S (Wladimir J. van der Laan)
2eae315 Replace uint256(1) with static constant (Wladimir J. van der Laan)
8076585 Replace GetLow64 with GetCheapHash (Wladimir J. van der Laan)
4f15249 Replace direct use of 0 with SetNull and IsNull (Wladimir J. van der Laan)
5d3064b Temporarily add SetNull/IsNull/GetCheapHash to base_uint (Wladimir J. van der Laan)

1 files changed, 290 insertions, 0 deletions

diff --git a/src/arith_uint256.h b/src/arith_uint256.h
new file mode 100644
index 0000000000..b6ba3a1087
--- /dev/null
+++ b/src/arith_uint256.h
@@ -0,0 +1,290 @@
+// 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
+
+#include <assert.h>
+#include <cstring>
+#include <stdexcept>
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+class uint256;
+
+class uint_error : public std::runtime_error {
+public:
+    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);
+
+    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 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;
+    }
+};
+
+/** 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) {}
+
+    /**
+     * 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;
+
+    friend uint256 ArithToUint256(const arith_uint256 &);
+    friend arith_uint256 UintToArith256(const uint256 &);
+};
+
+uint256 ArithToUint256(const arith_uint256 &);
+arith_uint256 UintToArith256(const uint256 &);
+
+#endif // BITCOIN_UINT256_H