Repository: bitcoin/bitcoin
File: src/script/script.h (C/C++)

Code before:
        {
            insert(end(), OP_PUSHDATA2);
            uint8_t _data[2];
            WriteLE16(_data, b.size());
            insert(end(), _data, _data + sizeof(_data));
        }
        else
        {
            insert(end(), OP_PUSHDATA4);
            uint8_t _data[4];
            WriteLE32(_data, b.size());
            insert(end(), _data, _data + sizeof(_data));
        }
        insert(end(), b.begin(), b.end());
        return *this;
    }

    bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
    {
        return GetScriptOp(pc, end(), opcodeRet, &vchRet);
    }

    bool GetOp(const_iterator& pc, opcodetype& opcodeRet) const
    {
        return GetScriptOp(pc, end(), opcodeRet, nullptr);
    }

    /** Encode/decode small integers: */
    static int DecodeOP_N(opcodetype opcode)
    {
        if (opcode == OP_0)
            return 0;
        assert(opcode >= OP_1 && opcode <= OP_16);
        return (int)opcode - (int)(OP_1 - 1);
    }
    static opcodetype EncodeOP_N(int n)
    {
        assert(n >= 0 && n <= 16);
        if (n == 0)
            return OP_0;
        return (opcodetype)(OP_1+n-1);
    }

    /**
     * Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
     * as 20 sigops. With pay-to-script-hash, that changed:
     * CHECKMULTISIGs serialized in scriptSigs are
     * counted more accurately, assuming they are of the form
     *  ... OP_N CHECKMULTISIG ...
     */
    unsigned int GetSigOpCount(bool fAccurate) const;

Review comment (suggestion):
In commit "Add std::byte span overload to CScript" (e6c02b9f2544032481743b4f8d3148622ccc73dd)

If code is moving away from `char` and `uint8_t` and towards `std::byte`, it would seem better for the `uint8_t` overload to call the `std::byte` overload (with `UInt8sToBytes`) instead of vice versa so the uint8_t overload could be dropped in the future without having to change this code again.

Code after:

    CScript& operator<<(opcodetype opcode) LIFETIMEBOUND
    {
        if (opcode < 0 || opcode > 0xff)
            throw std::runtime_error("CScript::operator<<(): invalid opcode");
        insert(end(), (unsigned char)opcode);
        return *this;
    }

    CScript& operator<<(const CScriptNum& b) LIFETIMEBOUND
    {
        *this << b.getvch();
        return *this;
    }

    CScript& operator<<(std::span<const std::byte> b) LIFETIMEBOUND
    {
        AppendDataSize(b.size());
        AppendData({reinterpret_cast<const value_type*>(b.data()), b.size()});
        return *this;
    }

    // For compatibility reasons. In new code, prefer using std::byte instead of uint8_t.
    CScript& operator<<(std::span<const value_type> b) LIFETIMEBOUND
    {
        return *this << std::as_bytes(b);
    }

    bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
    {
        return GetScriptOp(pc, end(), opcodeRet, &vchRet);
    }

    bool GetOp(const_iterator& pc, opcodetype& opcodeRet) const
    {
        return GetScriptOp(pc, end(), opcodeRet, nullptr);
    }

    /** Encode/decode small integers: */
    static int DecodeOP_N(opcodetype opcode)
    {
        if (opcode == OP_0)
            return 0;
        assert(opcode >= OP_1 && opcode <= OP_16);
        return (int)opcode - (int)(OP_1 - 1);
    }
    static opcodetype EncodeOP_N(int n)
    {
        assert(n >= 0 && n <= 16);
        if (n == 0)
            return OP_0;