OP_MASK

int FindAndMask(CScript& script)
{
    int masked = 0;
    bool skip_next = false;
    CScript result;
    CScript::const_iterator pc = script.begin(), pc2 = script.begin();
    opcodetype opcode;

    while (script.GetOp(pc, opcode)) {
        if (opcode == OP_MASK) {
            result.insert(result.end(), pc2, pc);
            skip_next = true;
            pc2 = pc;
        }
        else if (skip_next == true) {
            result.insert(result.end(), (unsigned char)OP_VERIF);
            skip_next = false;
            pc2 = pc;
            ++masked;
        }
    }

    if (skip_next == true) {
        script = CScript();
        return -1;
    }
    if (masked > 0) {
        result.insert(result.end(), pc2, static_cast<CScript::const_iterator>(script.end()));
        script = std::move(result);
    }

    return masked;
}

BOOST_AUTO_TEST_CASE(script_op_mask)
{
    // Exercise the FindAndMask functionality
    CScript s;
    CScript d;
    CScript e;

    s = CScript() << OP_1 << OP_2 << OP_3;
    e = s;
    BOOST_CHECK_EQUAL(FindAndMask(s), 0);
    BOOST_CHECK(s == e);

    s = ScriptFromHex("5101bd02febd");
    e = s;
    BOOST_CHECK_EQUAL(FindAndMask(s), 0);
    BOOST_CHECK(s == e);

    s = ScriptFromHex("5101bd02bd"); // invalid: incomplete push
    e = s;
    BOOST_CHECK_EQUAL(FindAndMask(s), 0);
    BOOST_CHECK(s == e);

    e = CScript() << OP_1 << OP_MASK << OP_VERIF;
    s = CScript() << OP_1 << OP_MASK << OP_DUP;
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);
    s = ScriptFromHex("51bd02feed");
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);
    s = ScriptFromHex("51bd02febd");
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);
    s = ScriptFromHex("51bd4e02000000feed");
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);
    s = CScript() << OP_1 << OP_MASK << OP_VERIF; // invalid: OP_VERIF
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);

    s = ScriptFromHex("51bd4e02000000feed02bdbd");
    e = ScriptFromHex("51bd6502bdbd");
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);

    s = ScriptFromHex("51bd4e02000000feed02bd"); // invalid: incomplete push
    e = ScriptFromHex("51bd6502bd");
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);

    s = CScript() << OP_1 << OP_IF << OP_MASK << OP_NOP8 << OP_ELSE << OP_MASK << OP_NOP9 << OP_ENDIF;
    e = CScript() << OP_1 << OP_IF << OP_MASK << OP_VERIF << OP_ELSE << OP_MASK << OP_VERIF << OP_ENDIF;
    BOOST_CHECK_EQUAL(FindAndMask(s), 2);
    BOOST_CHECK(s == e);

    s = CScript() << OP_1 << OP_MASK << OP_MASK << OP_3;
    e = CScript() << OP_1 << OP_MASK << OP_MASK << OP_VERIF;
    BOOST_CHECK_EQUAL(FindAndMask(s), 1);
    BOOST_CHECK(s == e);

    s = CScript() << OP_1 << OP_MASK << OP_MASK << OP_3 << OP_MASK;
    BOOST_CHECK_EQUAL(FindAndMask(s), -1);
    BOOST_CHECK(s == CScript());
    s = CScript() << OP_1 << OP_2 << OP_3 << OP_MASK << OP_MASK;
    BOOST_CHECK_EQUAL(FindAndMask(s), -1);
    BOOST_CHECK(s == CScript());
    s = CScript() << OP_1 << OP_2 << OP_3 << OP_MASK;
    BOOST_CHECK_EQUAL(FindAndMask(s), -1);
    BOOST_CHECK(s == CScript());
    s = CScript() << OP_1 << OP_2 << OP_NOTIF << OP_MASK; // invalid: inbalance condition
    BOOST_CHECK_EQUAL(FindAndMask(s), -1);
    BOOST_CHECK(s == CScript());
    s = ScriptFromHex("51bd02fe"); // invalid: incomplete push
    BOOST_CHECK_EQUAL(FindAndMask(s), -1);
    BOOST_CHECK(s == CScript());
}