ladybird/AK/UUID.cpp
Liav A 308e54bc19 AK+Kernel: Implement UUID mixed endianness support
This is being used by GUID partitions so the first three dash-delimited
fields of the GUID are stored in little endian order but the last two
fields are stored in big endian order, hence it's a representation which
is mixed.
2022-01-29 13:35:54 +02:00

109 lines
3.8 KiB
C++

/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/AllOf.h>
#include <AK/Hex.h>
#include <AK/StringBuilder.h>
#include <AK/UUID.h>
namespace AK {
UUID::UUID(Array<u8, 16> uuid_buffer)
{
uuid_buffer.span().copy_to(m_uuid_buffer);
}
void UUID::convert_string_view_to_little_endian_uuid(StringView uuid_string_view)
{
VERIFY(uuid_string_view.length() == 36);
auto first_unit = MUST(decode_hex(uuid_string_view.substring_view(0, 8)));
auto second_unit = MUST(decode_hex(uuid_string_view.substring_view(9, 4)));
auto third_unit = MUST(decode_hex(uuid_string_view.substring_view(14, 4)));
auto fourth_unit = MUST(decode_hex(uuid_string_view.substring_view(19, 4)));
auto fifth_unit = MUST(decode_hex(uuid_string_view.substring_view(24, 12)));
VERIFY(first_unit.size() == 4 && second_unit.size() == 2
&& third_unit.size() == 2 && fourth_unit.size() == 2
&& fifth_unit.size() == 6);
m_uuid_buffer.span().overwrite(0, first_unit.data(), first_unit.size());
m_uuid_buffer.span().overwrite(4, second_unit.data(), second_unit.size());
m_uuid_buffer.span().overwrite(6, third_unit.data(), third_unit.size());
m_uuid_buffer.span().overwrite(8, fourth_unit.data(), fourth_unit.size());
m_uuid_buffer.span().overwrite(10, fifth_unit.data(), fifth_unit.size());
}
void UUID::convert_string_view_to_mixed_endian_uuid(StringView uuid_string_view)
{
VERIFY(uuid_string_view.length() == 36);
auto first_unit = MUST(decode_hex(uuid_string_view.substring_view(0, 8)));
auto second_unit = MUST(decode_hex(uuid_string_view.substring_view(9, 4)));
auto third_unit = MUST(decode_hex(uuid_string_view.substring_view(14, 4)));
auto fourth_unit = MUST(decode_hex(uuid_string_view.substring_view(19, 4)));
auto fifth_unit = MUST(decode_hex(uuid_string_view.substring_view(24, 12)));
VERIFY(first_unit.size() == 4 && second_unit.size() == 2
&& third_unit.size() == 2 && fourth_unit.size() == 2
&& fifth_unit.size() == 6);
// Revert endianness for first 4 bytes
for (size_t index = 0; index < 4; index++) {
m_uuid_buffer[3 - index] = first_unit[index];
}
// Revert endianness for second 2 bytes and again for 2 bytes
for (size_t index = 0; index < 2; index++) {
m_uuid_buffer[3 + 2 - index] = second_unit[index];
m_uuid_buffer[5 + 2 - index] = third_unit[index];
}
m_uuid_buffer.span().overwrite(8, fourth_unit.data(), fourth_unit.size());
m_uuid_buffer.span().overwrite(10, fifth_unit.data(), fifth_unit.size());
}
UUID::UUID(StringView uuid_string_view, Endianness endianness)
{
if (endianness == Endianness::Little) {
convert_string_view_to_little_endian_uuid(uuid_string_view);
return;
} else if (endianness == Endianness::Mixed) {
convert_string_view_to_mixed_endian_uuid(uuid_string_view);
return;
}
VERIFY_NOT_REACHED();
}
String UUID::to_string() const
{
StringBuilder builder(36);
builder.append(encode_hex(m_uuid_buffer.span().trim(4)).view());
builder.append('-');
builder.append(encode_hex(m_uuid_buffer.span().slice(4).trim(2)).view());
builder.append('-');
builder.append(encode_hex(m_uuid_buffer.span().slice(6).trim(2)).view());
builder.append('-');
builder.append(encode_hex(m_uuid_buffer.span().slice(8).trim(2)).view());
builder.append('-');
builder.append(encode_hex(m_uuid_buffer.span().slice(10).trim(6)).view());
return builder.to_string();
}
bool UUID::operator==(const UUID& other) const
{
for (size_t index = 0; index < 16; index++) {
if (m_uuid_buffer[index] != other.m_uuid_buffer[index])
return false;
}
return true;
}
bool UUID::is_zero() const
{
return all_of(m_uuid_buffer, [](const auto octet) { return octet == 0; });
}
}