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/*
* Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Tar.h"
namespace Archive {
unsigned TarFileHeader::expected_checksum() const
{
auto checksum = 0u;
u8 const* u8_this = reinterpret_cast<u8 const*>(this);
u8 const* u8_m_checksum = reinterpret_cast<u8 const*>(&m_checksum);
for (auto i = 0u; i < sizeof(TarFileHeader); ++i) {
if (u8_this + i >= u8_m_checksum && u8_this + i < u8_m_checksum + sizeof(m_checksum)) {
checksum += ' ';
} else {
checksum += u8_this[i];
}
}
return checksum;
}
ErrorOr<void> TarFileHeader::calculate_checksum()
{
memset(m_checksum, ' ', sizeof(m_checksum));
bool copy_successful = TRY(String::formatted("{:06o}", expected_checksum())).bytes_as_string_view().copy_characters_to_buffer(m_checksum, sizeof(m_checksum));
VERIFY(copy_successful);
return {};
}
bool TarFileHeader::is_zero_block() const
{
u8 const* buffer = reinterpret_cast<u8 const*>(this);
for (size_t i = 0; i < sizeof(TarFileHeader); ++i) {
if (buffer[i] != 0)
return false;
}
return true;
}
bool TarFileHeader::content_is_like_extended_header() const
{
return type_flag() == TarFileType::ExtendedHeader || type_flag() == TarFileType::GlobalExtendedHeader;
}
void TarFileHeader::set_filename_and_prefix(StringView filename)
{
// FIXME: Add support for extended tar headers for longer filenames.
VERIFY(filename.length() <= sizeof(m_filename) + sizeof(m_prefix));
if (filename.length() <= sizeof(m_filename)) {
set_prefix(""sv);
set_filename(filename);
return;
}
Optional<size_t> slash = filename.find('/', filename.length() - sizeof(m_filename));
VERIFY(slash.has_value());
set_prefix(filename.substring_view(0, slash.value() + 1));
set_filename(filename.substring_view(slash.value() + 1));
}
}
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