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-rw-r--r--src/uint256.h339
1 files changed, 72 insertions, 267 deletions
diff --git a/src/uint256.h b/src/uint256.h
index 8189b27cb3..6d016ab164 100644
--- a/src/uint256.h
+++ b/src/uint256.h
@@ -13,217 +13,37 @@
#include <string>
#include <vector>
-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 base class for fixed-sized opaque blobs. */
template<unsigned int BITS>
-class base_uint
+class base_blob
{
protected:
- enum { WIDTH=BITS/32 };
- uint32_t pn[WIDTH];
+ enum { WIDTH=BITS/8 };
+ uint8_t data[WIDTH];
public:
-
- base_uint()
+ base_blob()
{
- for (int i = 0; i < WIDTH; i++)
- pn[i] = 0;
+ memset(data, 0, sizeof(data));
}
- 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;
- }
+ explicit base_blob(const std::vector<unsigned char>& vch);
- 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
+ bool IsNull() const
{
for (int i = 0; i < WIDTH; i++)
- if (pn[i] != 0)
+ if (data[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)
+ void SetNull()
{
- // postfix operator
- const base_uint ret = *this;
- --(*this);
- return ret;
+ memset(data, 0, sizeof(data));
}
- 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); }
+ friend inline bool operator==(const base_blob& a, const base_blob& b) { return memcmp(a.data, b.data, sizeof(a.data)) == 0; }
+ friend inline bool operator!=(const base_blob& a, const base_blob& b) { return memcmp(a.data, b.data, sizeof(a.data)) != 0; }
+ friend inline bool operator<(const base_blob& a, const base_blob& b) { return memcmp(a.data, b.data, sizeof(a.data)) < 0; }
std::string GetHex() const;
void SetHex(const char* psz);
@@ -232,122 +52,107 @@ public:
unsigned char* begin()
{
- return (unsigned char*)&pn[0];
+ return &data[0];
}
unsigned char* end()
{
- return (unsigned char*)&pn[WIDTH];
+ return &data[WIDTH];
}
const unsigned char* begin() const
{
- return (unsigned char*)&pn[0];
+ return &data[0];
}
const unsigned char* end() const
{
- return (unsigned char*)&pn[WIDTH];
+ return &data[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;
+ return sizeof(data);
}
unsigned int GetSerializeSize(int nType, int nVersion) const
{
- return sizeof(pn);
+ return sizeof(data);
}
template<typename Stream>
void Serialize(Stream& s, int nType, int nVersion) const
{
- s.write((char*)pn, sizeof(pn));
+ s.write((char*)data, sizeof(data));
}
template<typename Stream>
void Unserialize(Stream& s, int nType, int nVersion)
{
- s.read((char*)pn, sizeof(pn));
- }
-
- // Temporary for migration to opaque uint160/256
- 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;
+ s.read((char*)data, sizeof(data));
}
};
-/** 160-bit unsigned big integer. */
-class uint160 : public base_uint<160> {
+/** 160-bit opaque blob.
+ * @note This type is called uint160 for historical reasons only. It is an opaque
+ * blob of 160 bits and has no integer operations.
+ */
+class uint160 : public base_blob<160> {
public:
uint160() {}
- uint160(const base_uint<160>& b) : base_uint<160>(b) {}
- uint160(uint64_t b) : base_uint<160>(b) {}
- explicit uint160(const std::string& str) : base_uint<160>(str) {}
- explicit uint160(const std::vector<unsigned char>& vch) : base_uint<160>(vch) {}
+ uint160(const base_blob<160>& b) : base_blob<160>(b) {}
+ explicit uint160(const std::vector<unsigned char>& vch) : base_blob<160>(vch) {}
};
-/** 256-bit unsigned big integer. */
-class uint256 : public base_uint<256> {
+/** 256-bit opaque blob.
+ * @note This type is called uint256 for historical reasons only. It is an
+ * opaque blob of 256 bits and has no integer operations. Use arith_uint256 if
+ * those are required.
+ */
+class uint256 : public base_blob<256> {
public:
uint256() {}
- uint256(const base_uint<256>& b) : base_uint<256>(b) {}
- uint256(uint64_t b) : base_uint<256>(b) {}
- explicit uint256(const std::string& str) : base_uint<256>(str) {}
- explicit 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.
+ uint256(const base_blob<256>& b) : base_blob<256>(b) {}
+ explicit uint256(const std::vector<unsigned char>& vch) : base_blob<256>(vch) {}
+
+ /** A cheap hash function that just returns 64 bits from the result, it can be
+ * used when the contents are considered uniformly random. It is not appropriate
+ * when the value can easily be influenced from outside as e.g. a network adversary could
+ * provide values to trigger worst-case behavior.
+ * @note The result of this function is not stable between little and big endian.
*/
- uint256& SetCompact(uint32_t nCompact, bool *pfNegative = NULL, bool *pfOverflow = NULL);
- uint32_t GetCompact(bool fNegative = false) const;
+ uint64_t GetCheapHash() const
+ {
+ uint64_t result;
+ memcpy((void*)&result, (void*)data, 8);
+ return result;
+ }
+ /** A more secure, salted hash function.
+ * @note This hash is not stable between little and big endian.
+ */
uint64_t GetHash(const uint256& salt) const;
};
-// Temporary for migration to opaque uint160/256
-inline uint256 uint256S(const std::string &x) { return uint256(x); }
+/* uint256 from const char *.
+ * This is a separate function because the constructor uint256(const char*) can result
+ * in dangerously catching uint256(0).
+ */
+inline uint256 uint256S(const char *str)
+{
+ uint256 rv;
+ rv.SetHex(str);
+ return rv;
+}
+/* uint256 from std::string.
+ * This is a separate function because the constructor uint256(const std::string &str) can result
+ * in dangerously catching uint256(0) via std::string(const char*).
+ */
+inline uint256 uint256S(const std::string& str)
+{
+ uint256 rv;
+ rv.SetHex(str);
+ return rv;
+}
#endif // BITCOIN_UINT256_H