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https://github.com/RGBCube/serenity
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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.
117 lines
2.8 KiB
C++
117 lines
2.8 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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#include "Calculator.h"
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#include <AK/Assertions.h>
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#include <AK/Math.h>
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#include <LibCrypto/BigFraction/BigFraction.h>
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Crypto::BigFraction Calculator::begin_operation(Operation operation, Crypto::BigFraction argument)
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{
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Crypto::BigFraction res {};
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switch (operation) {
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case Operation::None:
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VERIFY_NOT_REACHED();
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case Operation::Add:
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case Operation::Subtract:
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case Operation::Multiply:
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case Operation::Divide:
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m_saved_argument = argument;
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m_operation_in_progress = operation;
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return argument;
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case Operation::Sqrt:
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if (argument < Crypto::BigFraction {}) {
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m_has_error = true;
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return argument;
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}
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res = argument.sqrt();
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clear_operation();
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break;
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case Operation::Inverse:
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if (argument == Crypto::BigFraction {}) {
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m_has_error = true;
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return argument;
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}
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res = argument.invert();
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clear_operation();
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break;
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case Operation::Percent:
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res = argument * Crypto::BigFraction { 1, 100 };
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break;
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case Operation::ToggleSign:
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res = -argument;
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break;
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case Operation::MemClear:
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m_mem.set_to_0();
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res = argument;
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break;
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case Operation::MemRecall:
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res = m_mem;
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break;
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case Operation::MemSave:
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m_mem = argument;
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res = argument;
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break;
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case Operation::MemAdd:
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m_mem = m_mem + argument; // avoids the need for operator+=()
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res = m_mem;
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break;
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}
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return res;
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}
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Crypto::BigFraction Calculator::finish_operation(Crypto::BigFraction argument)
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{
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Crypto::BigFraction res {};
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switch (m_operation_in_progress) {
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case Operation::None:
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return argument;
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case Operation::Add:
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res = m_saved_argument + argument;
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break;
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case Operation::Subtract:
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res = m_saved_argument - argument;
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break;
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case Operation::Multiply:
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res = m_saved_argument * argument;
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break;
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case Operation::Divide:
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if (argument == Crypto::BigFraction {}) {
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m_has_error = true;
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return argument;
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}
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res = m_saved_argument / argument;
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break;
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case Operation::Sqrt:
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case Operation::Inverse:
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case Operation::Percent:
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case Operation::ToggleSign:
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case Operation::MemClear:
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case Operation::MemRecall:
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case Operation::MemSave:
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case Operation::MemAdd:
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VERIFY_NOT_REACHED();
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}
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clear_operation();
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return res;
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}
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void Calculator::clear_operation()
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{
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m_operation_in_progress = Operation::None;
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m_saved_argument.set_to_0();
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clear_error();
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}
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