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serenity/Userland/Applications/Calculator/Keypad.h
Max Wipfli 7b53ca5309 Calculator: Use Checked to ensure entered values do not overflow
This replaces the types of m_int_value and m_frac_value with
Checked<u64> which makes it possible to check if the value overflowed
when entering a digit. If that happens, the digit will just be ignored.

This fixes #1263.
2021-05-23 23:18:54 +01:00

49 lines
1,022 B
C++

/*
* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/String.h>
// This type implements number typing and
// displaying mechanics. It does not perform
// any arithmetic operations or anything on
// the values it deals with.
class Keypad final {
public:
Keypad();
~Keypad();
void type_digit(int digit);
void type_decimal_point();
void type_backspace();
double value() const;
void set_value(double);
String to_string() const;
private:
// Internal representation of the current decimal value.
bool m_negative { false };
Checked<u64> m_int_value { 0 };
Checked<u64> m_frac_value { 0 };
u8 m_frac_length { 0 };
// E.g. for -35.004200,
// m_negative = true
// m_int_value = 35
// m_frac_value = 4200
// m_frac_length = 6
enum class State {
External,
TypingInteger,
TypingDecimal
};
State m_state { State::External };
};