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53eb35caba
The purpose of this patch is to support addition, subtraction, multiplication and division without using conversion to double. To this end, we use the BigFraction class of LibCrypto. With this solution, we can store values without any losses and forward rounding as the last step before displaying.
56 lines
1.4 KiB
C++
56 lines
1.4 KiB
C++
/*
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* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
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* Copyright (c) 2022, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/String.h>
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#include <LibCrypto/BigFraction/BigFraction.h>
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#include <LibCrypto/BigInt/UnsignedBigInteger.h>
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// This type implements number typing and
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// displaying mechanics. It does not perform
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// any arithmetic operations or anything on
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// the values it deals with.
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class Keypad final {
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public:
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Keypad() = default;
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~Keypad() = default;
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void type_digit(int digit);
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void type_decimal_point();
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void type_backspace();
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Crypto::BigFraction value() const;
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void set_value(Crypto::BigFraction);
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void set_to_0();
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String to_string() const;
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private:
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// Internal representation of the current decimal value.
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// Those variables are only used when the user is entering a value.
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// Otherwise, the BigFraction m_internal_value is used.
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Crypto::UnsignedBigInteger m_int_value { 0 };
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Crypto::UnsignedBigInteger m_frac_value { 0 };
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Crypto::UnsignedBigInteger m_frac_length { 0 };
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// E.g. for -35.004200,
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// m_negative = true
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// m_int_value = 35
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// m_frac_value = 4200
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// m_frac_length = 6
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mutable Crypto::BigFraction m_internal_value {};
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enum class State {
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External,
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TypingInteger,
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TypingDecimal
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};
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State m_state { State::External };
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};
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