33 lines
917 B
C++
33 lines
917 B
C++
/*
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* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include "Tar.h"
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namespace Archive {
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unsigned TarFileHeader::expected_checksum() const
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{
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auto checksum = 0u;
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const u8* u8_this = reinterpret_cast<const u8*>(this);
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const u8* u8_m_checksum = reinterpret_cast<const u8*>(&m_checksum);
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for (auto i = 0u; i < sizeof(TarFileHeader); ++i) {
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if (u8_this + i >= u8_m_checksum && u8_this + i < u8_m_checksum + sizeof(m_checksum)) {
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checksum += ' ';
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} else {
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checksum += u8_this[i];
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}
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}
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return checksum;
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}
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void TarFileHeader::calculate_checksum()
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{
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memset(m_checksum, ' ', sizeof(m_checksum));
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VERIFY(String::formatted("{:06o}", expected_checksum()).copy_characters_to_buffer(m_checksum, sizeof(m_checksum)));
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}
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}
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