251     *
252     * Bitcoin only uses this "compact" format for encoding difficulty
253     * targets, which are unsigned 256bit quantities.  Thus, all the
254     * complexities of the sign bit and using base 256 are probably an
255     * implementation accident.
256     */
257    arith_uint256& SetCompact(uint32_t nCompact, bool *pfNegative = nullptr, bool *pfOverflow = nullptr);
258    uint32_t GetCompact(bool fNegative = false) const;
259
260    friend uint256 ArithToUint256(const arith_uint256 &);
261    friend arith_uint256 UintToArith256(const uint256 &);
262};
263
264// Keeping the trivially copyable property is beneficial for performance
265static_assert(std::is_trivially_copyable_v<arith_uint256>);
266
267uint256 ArithToUint256(const arith_uint256 &);
268arith_uint256 UintToArith256(const uint256 &);
269
270extern template class base_uint<256>;
271
272#endif // BITCOIN_ARITH_UINT256_H
273