banan-os/bootloader/installer/GUID.cpp

75 lines
1.9 KiB
C++

#include "GUID.h"
#include <iomanip>
#include <cstring>
std::optional<uint64_t> parse_hex(std::string_view hex_string)
{
uint64_t result = 0;
for (char c : hex_string)
{
if (!isxdigit(c))
return {};
uint8_t nibble = 0;
if ('0' <= c && c <= '9')
nibble = c - '0';
else if ('a' <= c && c <= 'f')
nibble = c - 'a' + 10;
else
nibble = c - 'A' + 10;
result = (result << 4) | nibble;
}
return result;
}
std::optional<GUID> GUID::from_string(std::string_view guid_string)
{
if (guid_string.size() != 36)
return {};
if (guid_string[8] != '-' || guid_string[13] != '-' || guid_string[18] != '-' || guid_string[23] != '-')
return {};
auto comp1 = parse_hex(guid_string.substr(0, 8));
auto comp2 = parse_hex(guid_string.substr(9, 4));
auto comp3 = parse_hex(guid_string.substr(14, 4));
auto comp4 = parse_hex(guid_string.substr(19, 4));
auto comp5 = parse_hex(guid_string.substr(24, 12));
if (!comp1.has_value() || !comp2.has_value() || !comp3.has_value() || !comp4.has_value() || !comp5.has_value())
return {};
GUID result;
result.component1 = *comp1;
result.component2 = *comp2;
result.component3 = *comp3;
for (int i = 0; i < 2; i++)
result.component45[i + 0] = *comp4 >> ((2-1) * 8 - i * 8);
for (int i = 0; i < 6; i++)
result.component45[i + 2] = *comp5 >> ((6-1) * 8 - i * 8);
return result;
}
bool GUID::operator==(const GUID& other) const
{
return std::memcmp(this, &other, sizeof(GUID)) == 0;
}
std::ostream& operator<<(std::ostream& out, const GUID& guid)
{
auto flags = out.flags();
out << std::hex << std::setfill('0');
out << std::setw(8) << guid.component1 << '-';
out << std::setw(4) << guid.component2 << '-';
out << std::setw(4) << guid.component3 << '-';
out << std::setw(2);
for (int i = 0; i < 2; i++) out << +guid.component45[i];
out << '-';
for (int i = 2; i < 8; i++) out << +guid.component45[i];
out.flags(flags);
return out;
}