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- // Copyright (c) 2009-2010 Satoshi Nakamoto
- // Copyright (c) 2009-2014 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_UINT256_H
- #define BITCOIN_UINT256_H
- #include <assert.h>
- #include <cstring>
- #include <stdexcept>
- #include <stdint.h>
- #include <string>
- #include <vector>
- /** Template base class for fixed-sized opaque blobs. */
- template<unsigned int BITS>
- class base_blob
- {
- protected:
- enum { WIDTH=BITS/8 };
- alignas(uint32_t) uint8_t data[WIDTH];
- public:
- base_blob()
- {
- memset(data, 0, sizeof(data));
- }
- explicit base_blob(const std::vector<unsigned char>& vch);
- bool IsNull() const
- {
- for (int i = 0; i < WIDTH; i++)
- if (data[i] != 0)
- return false;
- return true;
- }
- void SetNull()
- {
- memset(data, 0, sizeof(data));
- }
- 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);
- void SetHex(const std::string& str);
- std::string ToString() const;
- unsigned char* begin()
- {
- return &data[0];
- }
- unsigned char* end()
- {
- return &data[WIDTH];
- }
- const unsigned char* begin() const
- {
- return &data[0];
- }
- const unsigned char* end() const
- {
- return &data[WIDTH];
- }
- unsigned int size() const
- {
- return sizeof(data);
- }
- unsigned int GetSerializeSize(int nType, int nVersion) const
- {
- return sizeof(data);
- }
- template<typename Stream>
- void Serialize(Stream& s, int nType, int nVersion) const
- {
- s.write((char*)data, sizeof(data));
- }
- template<typename Stream>
- void Unserialize(Stream& s, int nType, int nVersion)
- {
- s.read((char*)data, sizeof(data));
- }
- };
- /** 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_blob<160>& b) : base_blob<160>(b) {}
- explicit uint160(const std::vector<unsigned char>& vch) : base_blob<160>(vch) {}
- };
- /** 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_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.
- */
- 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;
- };
- /* 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
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